WO2016141153A1 - Apparatuses, systems, and methods for phantoms - Google Patents

Abstract

An example phantom may include a phantom body comprising a porous material including a plurality of interconnected pores, the phantom body comprising an inflow cannel, which in some examples may be wall-less. The channels may have a width greater than a diameter of the pores. The porous material may be saturated with a fluid and enclosed within an enclosure. The enclosure may include an inlet fluidly coupling an inflow channel to an exterior of the enclosure and an outlet fluidly coupling an outflow channel to the exterior of the enclosure. In some examples, the enclosure may include an imaging window which may be formed of a flexible material. In some examples, the enclosure may define a first chamber which encloses the phantom body and at least one fluid-filled chamber fluidly connected to the first chamber.

Description

APPARATUSES, SYSTEMS, A METHODS FOR PHANTOMS BACKGROUND

J Ultrasound Is commonly used to image, diagnose, monitor, and treat- a wide array of disorders, and new techniques are continually being developed. One technique, contrast enhanced ultrasound fCBUS), uses contrast agents, such as mierobuhhSes, mixed with one or more liquids, to improve ultrasound imaging, In order to test new CEOS techniques in a preclinical setting (or to test, new pmbes- f r CEliS), phantoms may be used that mimic different organs and tissues, Including the vascular system. Other uses of phantoms may include calibration, quali y assurance and control, performance testing, and pre-purchasing testing and evaluation. Thus, phantoms m be an important part of research, instrument validation, and training. However, therfe are no standardized or commercially-available phantoms, for example for use in contrast .enhanced ultrasoun (CEUS) imaging. Researchers and s stem engineers have used tubes in water Of hytlrogeis for flow studies, or dialysis tubing to mimic perfesioa hi capillary beds. However, these -^'substitutes ma be unrealistic, and may not allow for Imaging of niierobub les as might be seen k the mfcroeircu!ation during CEUS ima ing, Also, these substitutes typically do not provide ¾ suitable phantom on which clinicians and imaging technicians may train, thns clinicians and imaging te h icians are -often limited to. training on annuals or patients, which may not be practical

1002-1 Techniques are .generally described that include -apparatuses, systems and methods relating to phantoms. An example- phantom may include a an om body comprising -a pqrous: -material which includes a plurality of interconnected pores. The^■ phantom body may include an inflow channel and an outflow channel, each terminating inside ihe porous material and each having a width greater than a diameter of the pores. The porous material may be -saturated- with a fluid. The phantom may further include an enclosure sealingS enclosin the phantom body. The enclosure- may include an inlet fkidly coupling the inflow channel to an exterior of the enclosure and an outlet flu idly coupling the outflow channel to the exterior of the enclosure,

I } A phantom in accordance with further examples may i nclude a phantom body whic includes a porous material including a plurality of interconnected pores. The phantom body may include wail-less inflow a d outflow channels, each having a width^' greater man a diameter of me pores. The porous material may be saturated with a fluid and sealfngiy enclosed in an enclosure, which ma include a imaging window formed of a flexible mii e ria.1.

}^' According to further examples, - a phantom may include- & phantom body which includes a sponge ^'and a plurality of channels Formed in the sponge. One end of each of the plurality of channels may open into a surface of the sponge, and the s onge may be degassed and saturated with a fluid. The phantom may further include enclosure defining a first chamber enclosing- the phantom body and at least one .fluid-filled chamber iluidly connected to the first chamber. The enclosure may further include an inlet and an outlet- for iluidiy coupling the phantom body to:a» exterior of the enclosure.

BRIEF .ES RI fiTION OF THE PR A WiNGS

j The foregoing and other features of the present disclosure will b come more fully apparent from . the. following description and .appended claims, taken in conjunction with -the accompanying drawings, Understan in that these drawings depict only several examples in accordance with the disclosure and are, therefore, not. to be considered limiting- ^'of its scope, the- disclosure will, be described with additional specificity and. detail through use- of {he accompanying drawings, in which:

1 FIG; I is a illustration of an apparatus in accordance with some examples disclosed herein;

} FIG, 2 is an illustration of an apparatus in accordance with further examples disclosed herein;

} FIG, 3 is an illustration of an apparatus- in. accordance with further examples disclosed herein;

} PIG. 4 is an Illustration of an apparatu in accordance with further examples disclosed herein;

} FiG, 5 is an illustration of a phantom bod in accordance with some examples disc ί osed her i n ;

f FIG. 6 is an illustration of a cross-section of the phantom body of the apparatus:, of FIG. 5: |#12| FIG, 7 is as illustration of an apparatus according to further examples disclosed herein;

(013} FIG. is an illustration of a system according to sotne examples di sclosed herein : ( I4{ FIG. 9 shows exampl contrast and B-rnode ultrasound images, obtain using the apparatus^' in. PIG. 7; a id

JMSj FIG, 10 is an il lustration of an apparatus with a removable phantom ^'chamber according to some examples disclosed, herei n,

|0Ϊ6| in the following detailed description, reference is made t the accompanying dra ings, which form a part hereof, In the drawings, similar symbols typically identi similar components., unless context dictates otherwise. The illustrative examples described in .th etailed description, drawings, and claims?, are_. not meant to be .limiting. Other examples may be utilized, and other changes may he made, without departing from the spirit or scope Of the subject matter presented herein. fi will be readily understood that the as ects of the present disclosure, as generally described herein, and illustrated in the Figures, can fee arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are implicitly contemplated herein,

(017} Ultrasound is commonly used to ima e* diagnose, treat and monitor a wide arm of disorders, and new imaging techniques "are continually being developed. One technique, contrast enhanced, ultrasound (CEOS), uses contrast agents mised with one or more liquids to improve the, quality of ultrasound images, CEUS is becoming a powerful clinical too! for tumor detection and tissue eharaeier saiietL Already approved in the U.S. in cardiology, CEUS is being applied in radiology to detect and characterise liver, prostate, kidney, and breast: lesions. In 201 1 _? the European Federation of Societies for Ultrasound in Medicine and Biology added guidelines on the- clinical use of CEUS tor non-hepatic and hepatic, applications, it is also suggested that contrast agents may be used for therapy monitoring of patients undergoing cytotoxic and anttangiogenio treatment.

JdiOf it may be desirable to test new- CEUS techniques- in a reclinical^' setting (e„g., to test sew; probes for CEUS), in viim using a phantom in lieu of animal or human studies.

(019} An In vitrv phantom suitable for use m CEUS imaging (e.g. , for -use with contrast agents snch a microbubbies} ma be implemented in accordance with, the examples disclosed herein. Phantoms in accordance with the present disclosure ma be configured to mimic different organs and tissues, including the -vascular system. The disclosed phantoms can be formed in any suitable dimension. Phantoms of different di ensions may be designed for use with different medical instrumentation, such as different p obes (e.g., linear an curvilinear arrays, prostate probes, or the like).

#^'28{ lii some examples., an apparatus for use as a phantom, for exa ple_s for use in CEUS imaging may include a phantem body which is made from a porous material having a plurality of mtereooneeted pores and which is saturated with a fluid, and a container sealingly enclosing the phantom body . The porous material may be a synthetic material and may function, as tissue parenchyma, in some examples, the phantom body ma be implemented using a sponge, sucfc as a sponge made from polyvinyl alcohol (PVA) or other commercially- available materials. The spong may have an open-cell structure defining a plurality -©F isfereo&nectsd pores. Sponges having different properties (e.g., porosity) may be readily available^' (e.g., easily made or commercially available) ibr mimicking different types of organs or tissues. Phantoms us ng materi al other th an sponges may be implemented, with the pores of the material essentially emulating microvesseis and Including channels emulating larger vessels its the. tissue parenchyma. In some examples* the phantoms may be homogeneous {e.g., having a same or substantial !y the same porosity throughout), in some exa pl s, phantoms with heterogeneous properties may be implemented usin ^■■ inclusions of porous materials with different ^'properties.

#211 The: acoustic properties of the phantom can be- fused to match that of human soft tissues. For example, in the case of a sponge, the material properties of the sponge cat) be selected to represent the acoustical properties of human soft tissues. S me example parameters to consider for tailoring the phantom may be the speed at which sound travels through the phantom, the density , and the sound attenuation of the phaptom. For example, for human, soft tissue, a preferred sound speed may be from about 1450 em/s io about S 600 em s, a preferred density may be density approximating tha of water, and a preferred attenuation may be from about 03 dB cni/MH to about 1.2 dB/cn / Hz, with a frequency po er dependence of -· I .. Baefecatte may also be another parameter and may be considered when- selecting .th porou material for the phantom.

'22| The phantom body may include a plurality of wail-less Inflow and outflow channels, each having a width that is greater than diameter of the pores. The term wali-less may be used to imply that the channels are defined b the materiel of the phantom body, which may not otherwise include a separate material for forming walls of the channels. The channels may be, formed in the phantom body (e.g., sponge) by known fabrication techniques (e.g., !maeMning, -drilling or^', milling), is some examples, the channe s. may b formed through a casting process, for example, by ^'expanding the material of the phantom body into a moid wi !): inserts for defining ilm channels. The channels may inflow and outflow channels which may be provided irt variety of patterns through the phsntoni body. in- some examples, one Of more inflow- and outflow channels may he axialiy aligned, offset, parallel, mterdigitaied, or Otherwise arranged- i some eXafnpies, one or more inflow and outflow channels ma terminate in the porous material of the phantom body. In some examples, one or more inflow- and outflow channels ma not terminate hut may instead he connected. The terms inflow and outflow are used to refer to a direction of fluid flow during use of the phaatom. That is, in use. the phantom may operably form part of a fhridie system in which fluid flo s through the phantom body from one or more of the inflow channels towards one or sn re of the outflow channels, to facilitate flow, visualization such, as through. CEIJS imaging,

)23] l« use,_. the phantom bod is ^'saturated with fluid and enclosed within a .container. The phantom body may be hard when it is dry which may facilitate the forming of the channels. The phantom body may be enclosed i an enclosure, such as a container, which may include an imaging window formed of a flexible ^'m larial to facilitate the placement of an ultrasound probe against the phantom body. The flexible material may be any flexible material, and it may be desirable that the flexible material does not increase t he atiemtation of the system and is sufficiently n-ong to resist rapture under ^' normal use (e.g,, pressure within the container, applied pressure and flow rate), I^'n some examples, the phantom may ^'include an attenuating layer, which may be configured to attenuate ultrasonic waves to mimic a greater depth of transmission at the actual physical depth within She phantom^' body. For example, one or more attenuating layers may be provided between the imaging window and me. channels, such that transmission of waves to a given depth (e.g., 2cm, 3cm, or other) within the phantom is perceived as transmission to a -greater depth (e.g., 5.cm, 6e:ra, 7cr»_s 8cm, ^' ra, idem or more), in some examples, the phantom bod may include multiple layers of material, one or more of which may be porous, so as to mimic passage of the ultrasonic waves through different tissue.

24} FIG. I shows ao illustration of an example apparatus 100 which may he used -as- a phantom for CEIJS imaging, it will be appreciated that the illustration, may be out of scale aad certain features ma he exaggerated to facilitate- an understanding of the present disclosure. The apparatus includes a. phantom body 1 10 made from a porous material 102. The phantom body 1 10 may be saturated with a fluid, in some examples, the phantom body «iay be. made- fro a sponge, such as a PVA sponge. Sponges made from PVA typically have pores of greater uniformity, (e.g., in terms of size and orientation) than other sponge mater al (e. .. polyester sponges), which may he _.advantageous; in some applications. In ther examples, the sponge may be made, by wa of example, from polyester or

Otter porous materials that may be used may include agar gel, alginate, poiyviny1ehlori.de (PV^'C). as examples. In some examples, lew and high density polvurethane loam sponges* w ich may have pore sizes of about .800 pjft, ma be used, in some examples, a FVA sponge having a pore size ranging from about 200 pa¾ (e.g., fine PVA sponge) to abauf SOOfim (e.g., course FVA sponge) may be used.

#25| The phantom body 1 10 may be sealed in an enclosure 1:20, The enclosure may be flexible- or rigid, in some examples, the enclosure may include a rigid container. The enclosure may include an inlet and an outlet, -which may be disposed on opposite sides of the container, in some examples, the enclosure may define a .volume which is smaller than a n min l volume defined by Site porous .material (e.g., a volume of the porous material absent the application <»f physical force). In s.ueh examples, the porous material may be compressed when enclosed by the enclosure 120, The enclosure may be made from a Osxib!e material and may ½ suitable for imaging through the flexible material (e.g„ a material which does not increase the attenuation of sound waves transmitted to the phantom body). In some examples, the enclosure may be formed of flexible materia! arid wherein the imaging window 'maybe defined by the flexible material of the enclosure.

ft∑&i The-. hantom body may include a plurality of channels; J 12. One or more channels may be provided on an inflow side 121. These channels may be referred to as inflow channels- 1 14, One or more channels may be provided on an outflow side 123, which channels m be referred to as outflow channels 1 16. The terms inflow and outflow may he used to refer to the direction of fluid flow through the phantom body. The inflow and outflow sides may be arbitrar m that, in some examples, -the: pparatus may function equally well regardles of the ^'direction of fluid flow. In some examples, the apparatus and/or the phantom body itself may be symmetric and the inflow and outflow sides may be arbitrarily selected (e.g., flow may be created, through the apparatus either -from the inflow to the outflow side- or in the reverse direction). In same examples, channels may also be provided In transverse directions and/or fluid may be flowed transversely to simulate different tissue or conditions. In yet further examples, the phantom body 1 10- may include at least one transverse channel to the inflow and/or outflow channels and materials (e.g., porous -materials) having different properties from the porous material 102 may be provided within one or more^' of the- transverse channels. The phantom body 1 i 0 may include at least one manifold channel 18 formed -(e>g., machined, cast) in a surface of the porous material 102, The manifold channel 1 18 ma extend along, at leas a ortion of, a side (e.g., the outflow side 123 sod/or the inflow side 121} of the phantom body 1 10. The inflow channels 1 14 may be Ouidly connected a manifold channel 1 IS on the inflow side 121 and the outflow channels 1 16 may be fiuidly connected to a manifold channel 1 18 on the outflow side 123. In use, the manifold channel 1 18 may act to direct fluid towards the inflow channels 1 14 and outflow channels Π_.6. la some examples, ihe phantom body may not include -.a »anifoid channel 1 18.

| 2?{ its some examples, each of the channels 1 12 may open into a surface of the phantom body 1 10. That is, each channel 1 12 may have an opening at one end, which opening i!uidiy connects the interior of the channel to. the exterior of the phantom body 1 12. in some examples. Inflow a d outflow channels may open into opposite surfaces, of the phantom body i 10. in. other examples, inflow and outflow channels may open into adjacent surfaces of the phantom body 1 10, An Opening of an inflow channel may also fee referred to as inlet of the Inflow channel and an opening of the outflow channel may be referred to as as outlet of the outflow channel, in exam l s, In which the -phantom bod 1 10 includes a manifold channel 1 18, the itrflov? channels and the outflow channels m y open into- a respective manifold channel formed in a respective surface of the porous material 102.

|il2S In some examples, the channels may terminate at another end opposit the. opening at an interior portion of the phantom body 1 10. For example, referring to a first inflow channel 1 14a, the inflow channel 114a ma include an inlet 1 14a-! at on end of the inflow .channel 1 14a and an inflow channel terminus 1 14a-2 at the opposite end of the inflow channel 1 14. The terminus may be defined by a wall formed of the porous material.. Similarly, referrin to a first outflow channel 1 16a, the outflow channel 1 16a may include an outlet 1 i fia-l at one end of the outflow channel 1 16a and an outflow channel terminus 1 16a~2 at the opposite end of the^{■ .}outflow channel 1 16a. The terminus 116a-.2 may be defined by a wall formed of the porous material. The termini of the inflow and outflow channel may b spaced apart. In this manner, fluid flowing from the inflow channel 114a toward the outflow channel i f 6a, such as during use of the apparatus, may he: forced to pass through the porous material, disposed between the inflow and; outflow channels 1 14a, 1 16a, which ma emulate small vessel perfusion, i other examples, one or more of the channels may be connected forming one or more continuous channels through the porous material 102,

{02£| The inflow and outflow channels 1 14a and 3 16a, respectively, may be spaced by a region 1 17 of porous material disposed between the inflow and outflow channels 114a and 1 16a, During use, contrast agent -flowing from the inflow channel 1 14a towards the outflo channel 116a ay fee caused to perfuse through the -porous material of at ^'least a portion of the region 117. Images of flow through the channels 1 34a. 116a ami perfusion .through .region. 1 17, which ma be enhanced by the contrast agent, may be imaged for example using a contrast imaging- mode of an ujtrasoond imaging system, is some exam les, the channels may be axia!ly aligned and thus termini of the channel may be asiaily spaced. hi other example, as described below- with reference to PIG, 2, the channels ma be laterally spaced.

|β3*)| la some examples, the inflo and outflow channels- ^:-rjrtay be generally axfel!y aligned.

In the ilinstrated embodiment in FIG. I, the terminus i !4a-2 of the inflow channel 1 1.4a is aligned with the terminus 1 f6a-2 of the outflow channel 11 a, In some xamples, the inflow and outflow channels may be offset as will be described further, e.g., with reference to FIG, 2. in some examples, as in the illustrated embodiment in FICi. 1 , the phantom body may include a plurality of i nflow channels and a plurali of outflow channels. However, other number and combinations of channels are contemplated, so as to -mimic different Organs or parts of organ or tissues that may be of interest. Parameters of the chan nels, such as length, width of path, ma be tailored as may be appropriate for a particular application (e.g., to mimic different types of tissue^ In some examples, the channels may have a. circular ^'cross- section. In other examples, the channels may have a different cross-section (e.g., oval, square, or rectangular cross-section). In some examples, the shape of one or more of the c annels 120 may foe arbitrary .

{03 1 The: enclosure: 120 -.may include an inlet and an outlet for coupling at least" one of the inflow and outflow channels to an exterior of the enclosure. In some examples, the enclosure 1,20 may include an opening on eac of the inflo and outflow sides, which may be selectively sealed (e,g,, with a valve) and which may fanctioo as an inlet 124 and outlet 126, respectively, of the apparatus 100. The- apparatus 100 may be connected to a fluidic system an exam le of which is described with reference to FIG . 8. The flukiie system may include a bubble trap provided upstream of the inlet, a pump for circulating a fluid through the system and/or a reservoir for supplying a fluid and/or a. contrast agent, fewer or greater number of components, may be included. In some examples, the enclosure 120 may not include an inlet and an outlet and the enclosure 120 may -primarily be used for transport of the phanio body f032| FIG. 2 shows an illustration of an. example apparatus 200 which may be used as a phantom for CBUS imaging. The apparatus 200 may include components, features, or functionality which may be similar or the same as that of apparatus 100, and the description Of such components, features, or functionality may not be repeated. The apparatus 200 m include a phantom body 210 sealed ithin, an enclosure 220. -The phantom body 210 way he muds- from a porous material, such as sponge (e.g.. a. PVA sponge), which may be de assed and satu ated with a fluid (e.g., water, saline, or a body-mimicking fluid (BMF)}.. In this embodiment, the phantom body 2 I f) includes a plurality of sateidigitaied (or interleaved) channels 12. The channels 212 may include at leasi: one inflow channel 21.4 and ai least one Outflow^' channel 216, The channels 21 m She illustrated example are substantially (plus or minus 5 degrees) parallel In some exa ples, the -channels may be ngled relative to one another- For example, the distance between adjacent follow or outflow channels may increase or decrease along their respecti ve lengths.

i 33| The channels 212 may he imerdigitated but not intersecting. For example, & terminus portion 21 -2 of inflow channel 214 and term os. portion 21.6-2 of outflow channel 216 may be laterally spaced (e.g., by a distance d) from one another. In this manner, fluid flowing from an inflow channel toward atr outflow channel may be forced through the porous material - between she terminus portions of the inflow and outflow -channel. A region of porous material feg,, -region. 217} may be disposed between adjacent terminus portions of the channels- (e.g., between terminus portions 214-2 and 216-2), During use, contrast agent flowing from the inflow channel 214 towards the- outflow channel .216 may be caused to perfuse through the porous materia! of at least a portion of the region.217, and images of the flow through the cha nels and perfusion through region 21?, which may be enhanced by the contrast agent, may be imaged lor example using a. contrast imaging mode of an ultrasound imaging system. The widths. lengths, overlap (e.g., interdi itation), spacing, and other parameters of the channels- within the . phantom bod 10 may be tailored to suit a ^'particular application (e.g._» to mimic a particular organ or- tissue as may be desired). The phantom body 2.10 may include at least one manifold channel 218 which ma extend along, at least a portion of, a side of the -phantom -body 210. The Inflow and outflo channels may be fktkily connected a respecti ve manifold chan nel s 218 on respective sides of the phantom body 210.

&34f hi sonte examples, the enclosure 220 may be made from a -flexible material suitable lor imaging- through the flexible: material (e,g,, a material which does not increase the attenuation of sound waves transmitted to the phantom body), in some, examples, the enclosure 220 may include an opening on each, of the inflow and outflow sides, which may he selectively scaled e-.g., with a valve) and which may function as an inlet and outlet of the apparatus 200 such that the apparatus may be connected, to a fluidic system tor circulating a. flow and performing imaging operations, fits some examples, the enclosure 220 may sot include ah i nlet and an outlet and the enclosure 220 may primarily be used for transport of the phantom body 210.

¾35j FIG, 3 shows an illustration of an apparatus 300, which may provide a phantom, e.g., for use in CEUS imaging. The apparatus 300 includes a phantom body 310 and an enclosure (e.g., container 322). The p an om body 310 m&y he iwplemert!ed in ccordance with any of the examples herein (e.g., phantom body i 10, 210). in some examples, the phanto body 31.0 may be made from a porous material 302, such as a sponge and -may include a plurality of channels 312 (e.g., inflow and outflow channels. The channels 312 may be circular in cross-section. Parameters (e.g., length L, diameter D, taper, shape) of the channels 312, arrangement and number of the channels 312, as examples, may be tailored as may be appropriate for a particular application. Jt» some examples, the diameter of individual channels may be selected to correspond wit a diameter of large vessels within a tissue of interest (e.g., li er tissue, heart tissue, etc.) For ex m le* a channel having a diameter of about 0, cm may be used to emulate a large haptk vessel. Chatme!s_. having different dimensions, such as different widths or length, may be used to emulate vessels in different tissue, as well,

i\M\ The porous material may be selected to provide a desired ound speed, attenuation and power factor. For example, is the ease of a phantom for liver tissue, a PVA sponge w ich may provide attenuation from about 0,6 dB/cm/MIfe to about: 0,66 dB em/Mffe may be used io m re closely match the attenuation provided by liver tissue (e.g., about 0.6 dB/cnv^'Mife). In some examples, the inflow channels and the outflow channels may have the same, diameters and/or constant diameter along the lengths of the channels.. In some examples, individual ones of the channels may have different diameters along the length of the channels. In further examples., the diameter of one or more of the channels may vary (e.g., decrease) along a length of a channel such as to mimic a Harrowing of the diameter of large vessels towards smaller vessels. In some examples, the diameter may vary, continu usl or discontimtously along the length of a channel. Channels with a diseondnuousl varying diameter may- be formed, for example- by drilling concentric boreholes in the. phantom body, in some: examples, the channels.312 maybe ^'defined throug a casting- process, e.g., by expanding the material of the phantom body into a mold with inserts for defining the channels,

^'637} The- phantom body 31.0 may be -saturated with a fluid (e.g., water, saline, or a bod mimicking fluid) and may be- sealed within the container 322, Irs some examples, the container 322 may define one or m re chambers, including a phantom chamber 322- 1 , in which She phantom-body 310 may^' he disposed, in some examples, the phantom body 310 may he ked for a press fit- within the phantom chamber 322- 1 of the container 322. The container 322 may be mads from a rigid material such as acrylic or from a different type of materia!, in some examples, the container 322 may be made, at least partially, from a flexible material In some examples, the container or a portion thereof m be optically transparent, w scb may enable a use ^'to "visualize the flow of contrast agent. The container 322 may include walls 328 which may define the -a or more, chambers. In some examples, the container 322 may he manufactured as a Unitary body, for example as a monolithic component made ftom a single block of material by machining or by additive manufacturing, in some examples, the' container 322 may be constructed from separate components using conventional techniques, for example by mechanically fastening, adhering or laser welding plates of the materia! defining the walls 328. The container 322 may include as imaging windo 340 which may he configured for placing an imaging probe against th phantom body 310. The imaging window 340 may be implemented using a flexible materia; 342 such a a sheet of vinyl, which may he attached across an imaging opening 344 of the container 322. In some examples, the container 322 may include a removable access pane! 350, e.g., to enable the user to remove and/or replace the phantom body 31 , In some examples, the access panel 350 may be implemented in the form of a. removable cover of the container 322. in exa ples in which the container 322 is made from separable components (e.g., plana ^'or contoured walls), at least one of the waifs rnay be removably attached to other wails and ma function as the access panel 350,

!CiSj The phantom chamber 322- 1 may include an inlet opening 324 and an outlet opening 326, each fiuidly coupling the phantom body 310 with an exterior of the phantom chamber 322- ί . in some examples, the inlet opening 324, the outlet opening 326, or both may at least partially overlap an Met. (e.g., 3 i4a- i , 3 i4b- i ) or an outlet (e.g., 316a-L 3 ! f¾» i , 3 i 6c-l ) of one of the channels, in some examples, the inlet ^'opening and/or the outlet opening may be substantially aligned with one or more of the channels.

|»39 The apparatus 300 may be configured to reduce- the risk of bubble infiltration into the phantom body 310, targe bubble (e.g., bubbles greater than about ! Oum in diameter) may undesirably become lodged in the porous material 302, blocking fluid flow. To that end, the apparatus 300 may include a bubble trap 330 upstream from the inle opening 324, The bubble trap 330 may be implemented in the -form of a second chamber 322-2 defined by the container 322, The second chamber 322-2 ma be filled with a fluid to allow larger bubbles that may be introduced into the apparatus {^'e.g., through an inflow line) to float up in the

1 i fluid-filled chamber 322-2. The size of the second chamber 322-2 may be .determined, in part, on She arm of bubbles that may .need o be remo ed from the inflow of fluid. The second chamber may include an inlet opening 327 for eormecting an inflow line, as will be further descri ed; In this two chamber arrangement, the inlet opening 327 to the chambe 322-2 functions as the inlet of t e apparatus 300 and the outlet opening 326 irora the chamber 322-1. functions- as the outlet of the apparatus ^:3O0> The apparatus 300 may include a valve 325 across each of the ink-; d the outlet to flnidly seal the conte ts of the container 322. The valve 325 may be a one-way valve or another type of valve. When inflow -and -outflow lines ate connected to the apparatus 300, the valves 325 may be operable to allo -fluid to flow m one direction from the inflow side towards the outflow side (e.g., as shown by the arrows-Sol).

[048| FIG. 4 illustrates an apparatus 400 according to further examples of the present dsseloswre, "fhe apparatus 400 may Include One or more components that ate similar to those of the examples described with reference to FIGS. I --3, the description of which .may not be .repealed. For example, the apparatus 400 may include a. phantom body 410 with a plurality of -channels 412_* arts! art enclosure (e,g,_t container 422), The phantom body 419 may be implemented i accordance with any of the examples herein (e.g., phantom body 1 30, 2 S O, 310). The apparatus 406 may be similar to the apparatus 300 but may include two bubble traps each provided o either side of the phantom chamber, hi. some examples, and by Virtue of this s mmetry, - the..apparatus · may be configured for use with the inflow · and .outflow lines connected to- either side- of the apparatus 400, which may increase the case of ase of the apparatus, i other examples, the apparatus may be configured for .unidirectional use, e.g., as may be determined by the arrangement of valves or other flow control devices of the apparatus.

[0 1} More specifically, the. apparatus 400 includes a -phantom .chamber 4224 which encloses a phantom body 410, and further includes -first and second fluids-filled chambers 4224a» 422~2h. Each of the two fluid-filled chambers 4224a, 4224b is provided adjacent to and is fksidly connected to the phantom chamber 422-1, The first and second fluid-filled chambers 4224s, 422.4b may be provided on opposite sides of the phantom chamber 422- F Similar to the previous example, the container 4.22 may include an inlet 405 and an outlet 407, In some examples, a valve 425 (e.g., a cheek valve, or a two-way valve) may be provided at each of the- inlet and the outlet. An imaging window 440 may be provided along a side of the phantom chamber 422- 1 , for example along a top side of the container 42 between the first and second tluid- titled chambers 4224a, 4224b. The imaging window 440 may formed of a .flexible- Material ^'provided across an o ening in a wail of t e eo .tain.er 422, in s me examples, the container 422 may include a removable access panel 450, e.g., to enable the user to remove and/or replace the phantom, bod 410, la some examples, the container 422 may be- made from components (e_?g„ planar or contoured walls):, at least one of which may be removably attached to oilier walls ami may function as the access panel 450.

|«42j During use inflow nd outflow lines may be connected to the inlet and outlet of the apparatus (e.g., apparatus 400), fo example using -quick -release cpnaectprs such as Luer fittings. A pump (e.g., a peristaltic pump, a pulsatile p m , or another type of pump) may he connected to the inflow and outflow lines to circulate the flow through the system, is some examples, the pump may be upstream from the inlet and supply positive pressure.. In other examples, the pump may be downstream and. apply negative- pressure (e.g., suction) which may more closely mimic blood flow through the heart. The inflow line may be used to inject contrast agent, such as micro ubbles, which -may be mixed with the flow introduced into the apparatus via the inlet. The fluid circulated through the system may be blood mimickiBg fluid (BMF), imaging may be performed using any ultrasonic imaging _.systems, such as the EFIQ ultrasoun system provided by Philips Healthcare.

[043 j FIGS. 5 and 6 illustrate a- phantom body 10 for an apparatus in accordance with further examples of the present disclosure. The phantom body 5.10 may be used m combination with any of the apparatuses described herein. The phantom body 510 may be configured- to provide a phantom with heterogeneou properties. For example, the phantom body 5-10 may be- formed using a first porous material 502 and may be provided with one or more inclusion (e.g., 504- 1. 504-2, 504-3) comprising porous -materials, having different properties than the first porous material 502. As an -example, one or more of the inclusions (e,g,, 5044, 504-2·, 504-3} may have different properties (eg., pore size, pore density) than the. first -porous material 502, in some examples, one or more of the inclusions (e.g., 504- 1 , 504-2, 504-3) may have the same properties. In some examples, each of the inclusions may have different properties,

|M4| The phantom body 510 may include one or more of the features of phantom ^'bodies described with reference to other examples herein. For example, the phantom body 510 nay include channels 51.2 including at least one inflow channel 514 and at least one outflow channel 516. The channels 512 may be formed (e.g., drilled, or cast} In the porous material 502 before the porous material 502 is saturated with the fluid and inserted into an enclosure <e.g.« container 322, 422 ^! of apparatus 300, or 400, respectively). The channels 512 may be axf&ii aligned., offset, parallel, or angled relative to one another, fe some examples, the channels 512 may he curved. The channels may lie substantially within a plans o hi different pit®®, aiong a_: thickness t of the p rous material 502. In the illustrated example, the channels each inflow channel is axial^'ly aligned with, a respective outflow chattel and an inclusion is provided between each pair of inflow and outflow channels, in other examples, different arrangements may be xtsed, for example the inflow and outflow channels may be Offset from one another and the inclusion may occupy the space defined by the offset distance. One or more -channels 12 may be arranged m adjacent plane -(e..g-., parallel planes) along the thickness of the porous materia! 502 and inclusions may be provided between the adjacent planes to connect or substantially connect at least one portion of an inflo channel with at least one portion of an outflow channel. Other arrangements and combinations will be appreciated in view of the present disclosure, as may be appropriate to match different types of organs or tissue.

045} The phantom body S 1 may include at. least one manifold chaime! 5 ! S formed (eg., machined, cast) in a surface of the porous material 502. In some examples, an ink! manifold channel 18-1 may be provided on an inflow side 521 and sn outlet manifold channel 518-2 may be provided on the .outflow side 523. The Mow channels^' (e.g., channel 514) and the outflow channels (e.g., channel 516} may be f y idly connected to the inlet manifold channel 518-1 and She outlet manifold channel 518-2, respectively. The manifold channel 518 may extend along a side (e.g., the outflow side 523 anoVor the inflow side 521) of the phantom body 510; The- manifold channel 518 may extend only partially along the side which may reduce the amount of fluid flowing around the edges of the phantom body 10. That is, ends of the manifold channel 51 S^' may be spaced from the edges of the phantom body 510, e.g., by a distance s. In some exam les, the distance of the ends of the manifold channel 518 to the respective edges of the phantom body 51 may be e ual, in some examples, the distance of the ends of the manifold channel 18 to the edges of the phant m bod 510 may be unequal The distance of the ends of the manifold channel 518 to the edges of the phantom bod 51 may depend on parameters of the phantom body 510 (e.g., size and porosity of the phantom body 510, channel dimensions, etc.) and/or flow parameters (e.g., pressure, flow rate),

M6 As described, in some examples, the phantom body 510 may be formed, of a porous material, such as a sponge. Typically, the sponge may be solid-like and relatively hard when dry, which may facilitate the. forming f the channels < .g<, channel^'s 12, manifold channels 518} via. conventional techniques (^'e.g., drilling_, or machining}. In other examples, the phantom body formed and channel defined through a molding or easting process, For example, the channels illustrated in the exam le i FIG. 6 may be formed by first drilling the inflow and outflow channels, (e.g., drilling into the porous material torn the inflow aide and then from- tpe outflow side). T^'he inflow and outflow channels may not be connected to one another but may terminate within the ioteiior of she porous material, thereby defining respective terminus portions of each channel. The manifold channels 318 may b formed by drillin or machining a relatively shallow (e.g., about: 1/16 to about ¼ of an inch deep) arid nerally elongate trench along a surface ^'of the inflow and outflow sides. The inclusions^' 504-1 , 504-2,, and 504-3 may e provided into transverse openin s 506 in the porous materia] 502. The transverse openings 506 may be drilled ftom the front side 50? or the back side 509 of ike phantom body 510, through the thickness i to enable the insertion of another, porous material thesrein. The width (e.g., diameter) of each ofthe-opeaing 506 may correspond to the distance between a _.pair of inflow and outflow channels. The termini of the inflow and outflow channels in a pair may open into the same transvers opening flaidly connectin the inflow to the outflow channel -through the transverse opening to force- a flow to pass through the transverse opening and thereby through the inclusion provided therein. It will be understood that any of the phantom bodies (e.g., phatvto.ni body 1 0, 210, 31.0, 410, 1.0) described herein may be: -used in combination with any of the containers in any of the examples described herein, and contemplated embodiments of the present disclosure are not limited to the specific illustrated examples.

[ ? { Referring now to FIG. 7, a non-limiting example of an apparatus 700 configured^' as a liver phantom is described, targe vessels of liver -tissue- were emulated, with a plurality of channels consistent wit . si¾e- of the. haptic . artery formed Ί» a phan tom body 710 made from a sponge having a substantially uniform pore size of approximately I SO pin, which is representative of the icrOvasculature of liver tissue, in the illustrated example, a 17 -cm deep x 7 cm w ide x 3,25 cm. thick PVA sponge 703 was used. The .sponge was selected^' to provide attenuation similar to thai f liver tissue. The size of the sponge and dimensions of the container were such as to provide a tight lit {press or compression fit) between the sponge and the walls of the container so as to force most or substantially all of the flow through the sponge and reduce flow around the sides of the sponge.

j$48| Sixteen .3-4 cm, w&H-iesS: inter igltated vessels or chatmeis were drilled into the sponge 703, with eight, of the channels provided on the inflow side 721 and referred to as inflow channels arid eight of the channels provided on the outflow side ?2.3 and referred to as outflow channels. The vessels or channels from the two sides (i.e., inflo and outflow) are off-set forcing the flow to go through the sponge. The channels were drilled into the sponge before soaking and sealing the s onge 703 within a middle chamber (e.g.. phantom chamber 722-1} of the container 722, Different arrangement of channels, dimensions for the sponge and Channels, properties (e.g.. porosity or density) of the sponge, md a different number of channels may be used io other examples, e.g., to mimic differen types of organs or tissue.

\949\ The container 72 was implemented in the form of a generally rectangular box defining three chambers^' (middle chamber serving as the phantom chamber ^'722- 1 , and outer chambers 722-2 serving as bubbl e traps 730 %. The Avail 728 of the confess tier were made from, clear acrylic (e.g., HJ!XIGLAS)- The outer -chambers 722-2 were filled with ater to capture any larger bubbles that may otherwise block the flow through the pores of sponge 703 , A purge valve 752 (e.g., one-way valve) was pro ided on a top wall of each of the outer chambers 722-2. Inlet 705 and outlet 707 of the apparatus 700 were implemented using Lue? valves 754 to seal the contents of the apparatus 7(X^'s and enable quick connect and release of inflow and outflow lines 156- \ , 756-2, respectively. The apparatus 700 included an Imaging window 740 defined: y aft aperture 744 is the top wall of the container. A flexible material (e. g.. a sheet of vinyl) was provided across the aperture 744.

|f5§{ FIG. 8 which shows a system 800 In accordance with the present disclosure. During use. and referring no also to FIG. 8, a pump 762 (e.g., a pulsatile or peristaltic pamp) may be connected to the apparatus 700 to apply pressure and velocity waveforms to the fluid in the chambers to represent physiological flow conditions. In some examples, the pump 762 is used to apply positive pressure (e.g., to push the fluid through the inlet 705) or oegative pressure (e.g., to pull the fluid through the outlet 707), Flow rates of up to about.400 rnl mm were used, which is consistent with Ho rates in the hepatic artery. The fluid with which the phantom, body 710 is saturated may he water, saline or BMF. A supply reservoir 764 (e.g., a BMP reservoir) may he lluidly connected to the system, e.g.. via quick connect inserts isrio the tubing of the inflow and/or outflow lines. The inflow line may be used to inject contrast agent, such as nncTobobfoies, which. -may he mixed- with the flow introduced into the apparatus vi the inlet. During. t least some operating conditions, the temperature of the recireuiadng lluid was maintained^' at about 37 degrees. A transducer probe 766, con¾nustcatjveiy connected to- an imaging system (no? shown) may be positioned against the phantom body 710 via. the. imaging window 740 and ultrasound echoes may be obtained or imaging a flow of the contrast agent through the phantom body 710.

f®Sl f As- will be appreciated, contrast flow through art organ (such as a liver) typically includes; large vessel vascular inflow, small vessel perfusion throughout the tissue, then vascular outflow. While existing phantoms may not be able to emulate both large and small vessel vasculature the small vessel perfusion in which tissue hsckseatter and contrast backscatler are mi ed in the same volume elem nt, the phanto s in accor ance with the present disclosure may solve one or .more of the shortcomings Of e isting phantoms. F l 9 shows ultrasound images of microbobbles Slowing through a phantom contracted in in accordance with the present disclosure. FIG, 9(A) shows a contrast image and. PiG, 9(B) shows a B-tnode i mage. The images were obtained using .a phantom thai includes a phantom body made^{' '}ftoin a Sponge with i o £e rd feita ted c annels drilled into the sponge. The inflow ars l outflow channels- are not connected and perfusion of contrast agent through the sponge material between adjacent inflo and outflow channels.

j#S2 Phantoms in accordance with the present disclosure ay useful to researchers for developing new C.EIJS imaging techniques, .manufacturers of ultrasound systems for instrument validation,. and/or clinicians and technicians .tor education and training. Phantoms in accordance with the present disclosure may be useful in research studies, for calibration, algorithm^' development, testing and demonstration, and many other applications. Phantoms in accordance with the present disclosure may be cosfigared tor CBUS imaging over a broad range of depth to mimic different clinical scenarios, showing effects such as neariteld destruction phenomena arid &r6eld acoustic penetrauo-n. Phantoms in accordance with the present disclosure may provide a good image contrast between larger vessels and the perfused parenchyma and may provide the ability to study bubble resolution, destruction reperfusion, bolus injection washin/ ashont and destruction-replenishment kinetics. Phantoms in accordance with som examples may provide one o more or none of the aforementioned advantages and uses.

i#S3| In sonic examples, it ma be desirable to provide a. eplacement phantom body for an apparatus according to the present disclosure. In such examples, a replacement kit may include a replacement phantom body with die plurality of channels formed therein {e.g., as shown in FIG. I and 5). The phantom body may he degassed and saturated with the thud prior to being sealed within an enclosure (e.g., enclosure 120, 220) e.g., for transport. The enclosure may be a rigid enclosure or a flexible (e.g., vinyl) enclosure. As the replacement phantom body is already degassed and. fully saturated, replacement may easily be performed by submerging both · the sealed replacement . phantom body and the apparatus in a tank full of the fluid, removing the replacement phantom body from its enclosure, and inserting it into the phantom chamber (e.g., via the access panel) -in place of the old phantom body.

[654J FIG. 10 shows an apparatus 1.000 according to further examples. One or more of the components of the apparatus 1000 may be similar to components of other apparatuses described herein. For example, the apparatus 1000 nsay include a phantom body 101.0 which

1.7 may be usee! as a phantom fo OB US imaging. The phantom body 1010 may be formed of a porous .materia! which may Include eharme-b_. 1012 formed therein. In further examples, th phantom- body 1010 may he saturated with a fluid and sealed within a substantially rigid enclosure- 1020 (e.g., except for a flexible material thai i ttetions as a imaging window 1(540), The rigid enclosure 1020 may function as the phantom chamber. Use : enclosure 1-020 jafty be reniovabiy eonriecsabie to one or more additional chambers that may provide the fun tional t of bubble . traps. For example, the enclosure 1020 may be insertable within an outer container 1022 that defines a single chamber. The enclosure 1020 may be posiisonable at iiuermediate location, between sidewaiis of the outer container 1.022-, to define bubble traps 1.030 on -either side of the phantom chamber, la some examples, the outer container $02:2 may he sized such that only a single bubble trap is provided on the- inflow side of- the phantom chamber. A fter the enclosure 1020 is inserted into the outer container 1022, a cover "1029 may fee position over the opening: of containe 102:2 and attached (e.g., bond d or fastened) to the container 1.022 aod or enclosure - 1020. A s aling gasket may be provided between the containers and the: cover to ensure a water tight seal Each of the enclosure 1 20 and. container 1022 ma be provided with Inflow and outflow openings- for ilnidly corineetkvg the apparatus 1000 to a pump, a reservoir, or both to enable the injection and circulation of fluids (e.g., BMP, contrast agent) through the system.

[M5{ As described, the phantom body 101,0 may include one or more channels 1012. The hannel pay be provided in a variety of patterns through the phantom body_* In some examples, the channels S012 may include one or more inflow and one or more outflow channels. Inflow and outflow channels may be aligned, offset,, parallel, interdigitated, or otherwise arranged. The spacing between channels may be regular or irregular, in some examples, one or more inflow and outflow channels may terminate in the porous material of the phantom body. Is some examples, one or more inflow and outflow channels may nor terminate but may instead be connected thereby formin one or more continuous channels through the porous material. The individual channel geometry and/or arrangement of the channels in the porous material may e: tailored to emulate a variety of tissues or organs. In some examples, one-: or more of the channels may have constan width along a length of the channel i n some examples, one or more of the channels may have a varying width, such as a decreasing width towards the center of the phantom body. -Channels - ith decreasin width may be implemented in the form of continuously tapering (e.g., inwardly tapering) channels or ia the form of concentric bores with decreasing diameter towards the center. Numerous other arrangements or combinations can. fee im lemented without departing from the scope of the reset^ disclosure,

[β56 The present disclosure is not to be limited in terms of the- particular examples described: in this application, which are intended as Illustrations of various aspects. Many modifications and examples can he made without departing from its spirit and scope, as will, be a parent to those skilled in the art Functionally equivalent methods and apparatuses within the scope of (he disclosure, in addition those enumerated herein, will b .apparent to_. those skilled the art from the foregoing descriptions. Such modifications and examples are intended to fall within the scope of the appended claims. The ptssent disclosure is to he limited only by the terms of the appended claims, -along with the full scope of equivalents to winch such claims are entitled. It. is. to be understood that this disclosure is not limited so particular methods, reagents, compounds compositions or biological systems, which can, of course, vary, it ts.alsqto.be understood that the terminology used herein Is for the purpose of describing particular examples only, and is not intended, to be limiting.

If 57 W th respect to the use of substantially any plural and/or singular terms herein, those having sfcill in the art can translate from the plural to the singular and/or (torn the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended, claims (e,g>, bodies of the -appended claims) are generally intended as "open" terms (e.g., the term "including" ^''should be interpreted as "including but not limited to," the term "having" should be Interpreted as "havin at least," the term "includes" should be interpreted as "includes but is not limited to," etc.).

[§59 j It will he further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" ami "one or more" to Introduce claim recitations. However, the use of sseh phrases .should- not be construed to imply that the introduction of a claim^' ecitation by the indefinite articles "a." or "art" limits any particular claim containing such introduced claim recitation to example containing' only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least, one" and indefinite articles such ax "a⁵* or "an" (e.g., "a" arid/or ^Man" should be interpreted to mean "at least one" or "one or more"}; the same holds true for the use of definite articles us d to intro uce claim recitations. in addition, even if a specific number of an -introduced claim recitation is explicitl recited, those skilled In the art will recognize that su h recitation should be inte reted to mean at least the recited number ie,g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or snore recitations).

As will be understood: by one skilled in the art, for any mid all purposes, such s iff terms of providing a -written description, ail ranges disclosed herein also encompass any md all -possible -subranges and combinations- of s branges thereof. Any Iked. -.range -can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can. be .readily broken down into a lower third, -middle third and upper third, etc. As will also be understood by one skilled in the art: all language such as "up to," "at least," "greater than," "less than," and the like include the number recited sod refer to ranges which can be subsequently broken down nto subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 items refers to groups having 1 , 2, or^' 3 items. Similarly, ^'a group-having: 1-5 - items refers to groups ¾aving 1. 2, 3, 4, or 5 itcrus, and. so forth.

[06 While the f regoing detailed description has set forth various- examples of apparatuses which may include one or more components or provide one or more functions, it will be understood b those within the- art^' that each component and/or unction of any of the examples herein may be implemented in combination with other components or functions of any of the other examples des cribed herei n.

\Q61{ The herein described subject matter sometimes Illustrates different components contained, within, or connected with, different other components, it is to be understood that such depicted architectures are merely examples, and that in fact many other architectures can be implemented which achieve the same functionality, in a conceptual sense, an arrangement of components to achieve the same functionality is. effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular lunctionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures: or intermedial components. Likewise, any two components so associated can also be viewed as being "operabiy connected", or "operabiy coupled", to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operabiy eoupiabie^;1, to each other to achieve the desired functionality. Specific examples of operabiy eooplable include but are not limited -^'to physically mateabie and/or- physically interacting com onents and/or wire!essiy mteractable and or wirelessly interacting components and/or logically interacting andV r logically ^'interaetable components.

While various aspects and examples have been disclosed herein, other aspects and examples will be apparent to those skilled in the art. The various- aspects tnid examples disclosed ^'herein are for urp ses of ilkislTaiion and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

What i claimed is;

1. A phantom comprising:

a phantom body comprising a porous material including .a plurality af interconnected ores, wherein the pha om body farther comprises an inflow channel and outflow channel, formed its the por us material each of the Inflow channel and the outflow channel tenrnnating insi.de the porous material and each having a width, greater than a diameter of the pores, and. herein the porous material is saturated with a fluid; and

an enclosure seslirsgiy enclosin -the- phantom -body, the enclosure comprising an inlet fliiidi coupling the inflow channel to an exterior of the enclosure- and an outlet: fiuidly coupling- She outflow channel to the exterior of the enclosure.

2. The phantom of claim I , wherein the phanfoai body is made from a sponge.

3 The phantom of claim -2, wherein the sponge is a. polyvinyl -alcohol- fPVA) sponge.

4. The phantom of any of claims 1-3, wherein each of the inflow channel and the ouiflow channel has a terminus, and wherein respective termini of the inflow and outflow channel are ax ί ally spaced apart by a region of porous materia!.

5. The phantom of any of claims 1.-3, wherein each of the inflow channel and the outflow channel ^'has a terminus portion, and wherein respective terminu portions of the inflow and^' .outflow chaanel are laterally spaced apart by a region of porous material.

6. The phantom of any of claims. 1-5, wherein the phantom body comprises a plurality of inflow channels interdigkated with a plurality of outflow channels,

7. The phantom of any of claims i-6, wherein the phantom body comprises a plurality of inflow channels and a plurality of outflow channels-, each of the plurality of inflow channels fiuidly connected to an inflow manifold channel which is fiuidly connecte to the inlet, sad each of the pluraHty of outflow channels fluidly connected to an ouiflow :maniibid channel which is fluidl connected to the outlet.

8. The haotom of any of claims 1.-7, wherein the enclosure defines a phantom chamber and wherein the phantom body is press fit into the phantom chamber.

9. The phantom of claim 8, wherein the enclosure further ^'d@ii.nes a iifst finid- fi!!ed chamber adjacent to arid ^' flu idly connected, to the phantom chamber.

10. The ^'phantom, of claim 9, wherein the enclosure further defines a second fhrid- Slied chamber adjacent to and fiuidly connecte to the phantom chamber, the second fluid- filled e!msnber disposed on the opposite side of^" die hantom chamber if om the first fluid- f led chamber.

1 ! . The phtmtom of claim 9 or !0, wherein the first iluid-fitfed chamber comprises a p¾rge valv .

12. The phantom of any of claims - i 1 , wherein the enclosure comprises a rigid container, the enclosure further comprising an imaging window formed of a flexible material. 3. A phantom comprising:

a phantom body comprising a porous material including a plurality of interconnected pores, the phantom, body comprising wall-les inflow, and outflow channels, each having a width greater ^'than a diameter of the poms, and wherein the porous material is saturated with a fluid; and

an enclosure sealingiy enclosing the phantom body, wherein the enclosure comprises an imaging window formed of a -flexible material.

14. The hantom of claim S 3_» wherein enclosure comprises an inlet and an outlet Xiuidiy coupled to the inflow and outflow channels, respectively,

15. The apparatus of claim. 13 or 14, wherein the enclosure comprises a rigid container and wherein the inlet and outlet are disposed on opposite sides of the container.

16. The phantom of claim 13 or 14, wherein^" the enclosure comprises a flexible materi l,. and wherein the Imaging window is defined by the flexible- material of the

17. The phantom of an ©f claims 3-1 , wherein the inflow and outflow channels are connected forming a continuous channel f rough th porous material.

18. The phantom of any of claims 13-17, wherein the phantom body is made from a sponge,

19. The phantom of any of claims 13-- 18, f rther comprising a- second porous material disposed between the inflow channel and the outflow channel, she second porous material .^'having different porosity than the porous material of the phantom body,

20. The p ant m of claim 19, wherein the porous material comprises a trans verse channel to the inflow ^'chanrie! and; the outflow channel, sod wherein- the second porous material is disposed within the transverse channel,

25 , The phantom of any of claims 13-20, wherein the phantom body comprises a plurality of inflow channels and s plurality -Of outflow ^.channels, the plurality of inflow channels rloidly connected to an mi ow manifold channel formed in the porous materia!, and wherein the plurality of outflow channels are fiuidiy connected to an outflow ^aHilbld channel formed io. fhe porous material.

2¾. The phantom of any of claims 13-21 , further comprising a. plurality of inclusions between adjacent inflow and outflow channels,: each of the plurality, of inclusion havi g different porosity, density, or both, lhan the porous materia!,

23, A phantom comprising:

a phanto body comprising a sponge and a plurality of channels formed in the sponge, one end f each of the _.plurality of channels openin into a- surface of fhe sponge, arid- whereio the sponge is degassed and saturated with a fluid; and an enclosure defining a first chamber enclosin the phantom, body and at least one f!ukMflfod chamber iluiMy connected tp the first chamber, she enclosure further comprising an inlet and an outlet for ilnidSy coupling the phantom body to an exterior of the enclosure.

24. The phantom of claim 23, wherein the plurality of channels included a plurality of inisrdSgi sd eharmeis.

25. The phantom, of la m 24, wherein the plurality f mterdigitated channels i»cl uctes parallel mtetdigitated channels.

26. The phantom of any of claims 23-25, further comprising., a valve operably ertgaged with each of the inlet and the outlet.

2.7, The phan om of any of claims 23-26, furthe coiriprisiag an inclusion inserted m the phantom body between two adjacent channels of lbs plurality of channels, wherein the ^•inclusion includes ¾ ^'porous -material having different properties ..from the sponge,

28. A system including a phantom of any of claims 1 -27, wherein the phantom is fkiidly coupled to a pump configured to generate a flow of fluid ^'through the phantom.

29. The system of claim 28, wherein the pump is d stre m from art. outlet of the. phantom.

30. The sy stent of claim 28 or 29, further configured to inject a eoiUrast agent into the fluid.