MicroCT scanner performance and considerations for vascular specimen imaging

Marxen, Michael; Thornton, Michael; Chiarot, Cameron B.; Klement, Giannoula; Koprivnikar, Janet; Sled, John G.; Henkelman, R. Mark

doi:10.1118/1.1637971

Cited by 117 publications

(104 citation statements)

References 19 publications

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“…15,19,20 However, contrast enhancement of vasculature could be uneven, especially in non-tree-like microvascular beds, owing to incomplete perfusion as well as inhomogeneous dispersion, settling, or clumping of contrast materials during infusion. 27 Given that vascular image intensity is spatially heterogeneous and not so very different locally from bone image intensity, segmentation into microvasculature and bone is not straightforward even by synchrotron radiation mCT.…”

Section: Discussionmentioning

confidence: 99%

Subtraction micro-computed tomography of angiogenesis and osteogenesis during bone repair using synchrotron radiation with a novel contrast agent

Matsumoto

Goto

Sato

2013

Laboratory Investigation

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Quantitative three-dimensional (3D) imaging of angiogenesis during bone repair remains an experimental challenge. We developed a novel contrast agent containing 0.07-to 0.1-mm particles of zirconium dioxide (ZrCA) and established subtraction mCT using synchrotron radiation (sSRCT) for quantitative imaging of angiogenesis and bone repair. This method was applied to a rat model of tibial bone repair 3 days (DAY3; n ¼ 2), 5 days (DAY5; n ¼ 8), or 10 days (DAY10; n ¼ 8) after drill-hole injury. Using the same drill-hole defect model, its potential use was illustrated by comparison of bone repair between hindlimbs subjected to mechanical unloading (n ¼ 6) and normal weight bearing (n ¼ 6) for 10 days. Following vascular casting with ZrCA, the defect site was scanned with 17.9-and 18.1-keV X-rays. In the latter, image contrast between ZrCA-filled vasculature and bone was enhanced owing to the sharp absorption jump of zirconium dioxide at 18.0 keV (k-edge). The two scan data sets were reconstructed with 2.74-mm voxel resolution, registered by mutual information, and digitally subtracted to extract the contrast-enhanced vascular image. K 2 HPO 4 phantom solutions were scanned at 17.9 keV for quantitative evaluation of bone mineral. Angiogenesis had already started, but new bone formation was not found on DAY3. New bone emerged near the defect boundary on DAY5 and took the form of trabecular-like structure invaded by microvessels on DAY10. Vascular and bone volume fractions, blood vessel and bone thicknesses, and mineralization were higher on DAY10 than on DAY5. All these parameters were found to be decreased after 10 days of hindlimb unloading, indicating the possible involvement of angiogenesis in bone repair impairment caused by reduced mechanical stimuli. In conclusion, the combined technique of sSRCT and ZrCA vascular casting is suitable for quantitative 3D imaging of angiogenesis and its surrounding bone regeneration. This method will be useful for better understanding the linkage between angiogenesis and bone repair.

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Section: Discussionmentioning

confidence: 99%

Subtraction micro-computed tomography of angiogenesis and osteogenesis during bone repair using synchrotron radiation with a novel contrast agent

Matsumoto

Goto

Sato

2013

Laboratory Investigation

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“…Following a published protocol, 9 the descending aorta was cannulated and heparinized phosphatebuffered saline (5 U/mL) was perfused at a constant pressure of 100 mmHg until the blood was flushed from the vascular system. Animals were then perfused with 25 mL of Microfil Ò solution (MV-122; Flow-Tech, Carver, MA).…”

Section: Perfusion Studiesmentioning

confidence: 99%

Chimeric Vessel Tissue Engineering Driven by Endothelialized Modules in Immunosuppressed Sprague-Dawley Rats

Chamberlain

Gupta

Sefton

2011

Tissue Engineering Part A

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Modular tissue engineering is a means of building functional, vascularized tissues using small (*1 mm long 0.5 mm diameter) components. While this approach is being explored for its utility in adipose and cardiac tissue engineering and in islet transplantation, the initial question in this study was to assess the fate of the endothelial cells (EC) after transplantation delivered on the surface of modules, without an embedded cell. Rat aortic ECcovered collagen gel modules were transplanted into the omental pouch of allogeneic (outbred) Sprague-Dawley rats with and without immunosuppressive drug treatment (atorvastatin and tacrolimus) for 3-60 days. There was a significant increase in vessel density at all time points in the drug treated rats as compared to untreated rats. Green fluorescent protein (GFP)-positive donor rat aortic EC migrated from the surface of the modules and formed primitive vessels by day 7. In the untreated rats, the GFP-positive cells were not seen after day 7. In drugtreated rats, GFP-positive vessels matured over time, accumulated erythrocytes, were supported by host smooth muscle cells, and formed chimeric vessels that survived until day 60. This resulted in the formation of a densely vascularized, perfusable network by day 60. To our knowledge, this is the first study that demonstrates that primary unmodified EC, without the addition of supporting cells, form a chimeric and stable vascular bed in allogeneic, although drug-treated, animals.

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“…28 Data were acquired using the following parameters: volumetric cone-beam acquisition, 80 kVp and 80 A, FOV 15 or 33 mm (depending on size of specimen), 360°a cquisition, 720 views, 0.5°angle increment, 3 averages, and 0.020-inch thick aluminum filter. Volumes were reconstructed using a Feldkamp cone beam algorithm, with typical resolution of 33-m isotropic voxels (voxel volume 3.59ϫ10 Ϫ5 mm 3 ).…”

Section: Ct Imagingmentioning

confidence: 99%

Mineral Volume and Morphology in Carotid Plaque Specimens Using High-Resolution MRI and CT

Wolf

Wehrli

Popescu

et al. 2005

ATVB

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Objective-High-resolution MRI methods have been used to evaluate carotid artery atherosclerotic plaque content. The purpose of this study was to assess the performance of high-resolution MRI in evaluation of the quantity and pattern of mineral deposition in carotid endarterectomy (CEA) specimens, with quantitative micro-CT as the gold standard. Methods and Results-High-resolution MRI and CT were compared in 20 CEA specimens. Linear regression comparing mineral volumes generated from CT (V CT ) and MRI (V MRI ) data demonstrated good correlation using simple thresholding (V MRI ϭϪ0.01ϩ0.98V CT ; R 2 ϭ0.90; thresholdϭ4ϫnoise) and k-means clustering methods (V MRI ϭϪ0.005ϩ1.38V CT ; R 2 ϭ0.93). Bone mineral density (BMD) and bone mineral content (BMC [mineral mass]) were calculated for CT data and BMC verified with ash weight. Patterns of mineralization like particles, granules, and sheets were more clearly depicted on CT. Conclusions-Mineral volumes generated from MRI or CT data were highly correlated. CT provided a more detailed depiction of mineralization patterns and provided BMD and BMC in addition to mineral volume. Key Words: magnetic resonance imaging Ⅲ computed tomography Ⅲ carotid arteries Ⅲ calcium A significant fraction of all ischemic strokes is caused by carotid atherosclerosis. Degree of stenosis is a major risk factor, but factors unrelated to the extent of vascular constriction play a role in causing neurological symptoms, including the morphology and composition of the atherosclerotic plaque. 1,2 Components of plaque associated with symptoms ("vulnerable plaque") include surface ulceration, thinning of fibrous cap, presence of hemorrhage, lipid core, and inflammation and neovascularity. [3][4][5][6] Dystrophic calcification (mineralization) and even lamellar bone have been described in carotid plaques. 7,8 There is evidence for an association between plaque lipid and dystrophic mineralization. 9 Using confocal microscopy, Sarig et al 10 found that cholesterol or associated lipids may act as a nucleus for hydroxyapatite crystal formation. It is unclear to what extent carotid plaque calcification affects the risk of embolic stroke. Certain patterns of calcification may help grade lesions and provide an indicator of stability. 11 The potential role of MRI for noninvasive assessment of plaque morphology and lesion burden quantification has been addressed in several investigations ex vivo and in vivo. [12][13][14][15][16][17][18][19][20][21][22][23][24] The appearance of plaque calcification has been described as uniformly dark in signal intensity on all MRI sequences. 18,25,26 However, there are other components of atherosclerotic plaque that may show decreased signal intensity on some or all pulse sequences; for example, solid cholesterol hydrate may be present and plaque lipids may exhibit T2 shortening secondary to liquid crystal behavior, depending on the lipid composition and cholesterol content. 20,27 Induced magnetic field inhomogeneities caused by differences in diamagnetic susceptibility betw...

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MicroCT scanner performance and considerations for vascular specimen imaging

Cited by 117 publications

References 19 publications

Subtraction micro-computed tomography of angiogenesis and osteogenesis during bone repair using synchrotron radiation with a novel contrast agent

Subtraction micro-computed tomography of angiogenesis and osteogenesis during bone repair using synchrotron radiation with a novel contrast agent

Chimeric Vessel Tissue Engineering Driven by Endothelialized Modules in Immunosuppressed Sprague-Dawley Rats

Mineral Volume and Morphology in Carotid Plaque Specimens Using High-Resolution MRI and CT

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