Impact of Effective Detector Pixel and CT Voxel Size on Accurate Estimation of Blood Volume in Opacified Microvasculature

Mahya Sheikhzadeh, Andrew J. Vercnocke, Shengzhen Tao, Kishore Rajendran, Shuai Leng, Erik L. Ritman, Cynthia H McCollough

Research output: Contribution to journalArticle

Abstract

Rationale and Objectives: The purpose of this study was to determine the impact of effective detector-pixel-size and image voxel size on the accurate estimation of microvessel density (ratio of microvascular lumen volume/tissue volume) in an excised porcine myocardium specimen using microcomputed tomography (CT), and the ability of whole-body energy-integrating-detector (EID) CT and photon-counting-detector (PCD) CT to measure microvessel density in the same ex vivo specimen. Materials and Methods: Porcine myocardial tissue in which the microvessels contained radio-opaque material was scanned using a micro-CT scanner and data were generated with a range of detector pixel sizes and image voxel sizes from 20 to 260 microns, to determine the impact of these parameters on the accuracy of microvessel density estimates. The same specimen was scanned in a whole-body EID CT and PCD CT system and images reconstructed with 600 and 250 micron slice thicknesses, respectively. Fraction of tissue volume that is filled with opacified microvessels was determined by first subtracting the mean background attenuation value from all voxels, and then by summing the remaining attenuation. Results: Microvessel density data were normalized to the value measured at 20 µm voxel size, which was considered reference truth for this study. For emulated micro-CT voxels up to 260 µm, the microvessel density was underestimated by at most 11%. For whole-body EID CT and PCD CT, microvessel density was underestimated by 9.5% and overestimated by 0.1%, respectively. Conclusion: Our data indicate that microvessel density can be accurately calculated from the larger detector pixels used in clinical CT scanners by measuring the increase of CT attenuation caused by these opacified microvessels.

Original languageEnglish (US)
JournalAcademic Radiology
DOIs
StateAccepted/In press - Jan 1 2018

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Microvessels
Blood Volume
Photons
Swine
X-Ray Microtomography
Myocardium

Keywords

  • Computed tomography (CT)
  • CT image voxel size
  • Detector pixel size
  • Microvessel
  • Spatial resolution

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this

Impact of Effective Detector Pixel and CT Voxel Size on Accurate Estimation of Blood Volume in Opacified Microvasculature. / Sheikhzadeh, Mahya; Vercnocke, Andrew J.; Tao, Shengzhen; Rajendran, Kishore; Leng, Shuai; Ritman, Erik L.; McCollough, Cynthia H.

In: Academic Radiology, 01.01.2018.

Research output: Contribution to journalArticle

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title = "Impact of Effective Detector Pixel and CT Voxel Size on Accurate Estimation of Blood Volume in Opacified Microvasculature",
abstract = "Rationale and Objectives: The purpose of this study was to determine the impact of effective detector-pixel-size and image voxel size on the accurate estimation of microvessel density (ratio of microvascular lumen volume/tissue volume) in an excised porcine myocardium specimen using microcomputed tomography (CT), and the ability of whole-body energy-integrating-detector (EID) CT and photon-counting-detector (PCD) CT to measure microvessel density in the same ex vivo specimen. Materials and Methods: Porcine myocardial tissue in which the microvessels contained radio-opaque material was scanned using a micro-CT scanner and data were generated with a range of detector pixel sizes and image voxel sizes from 20 to 260 microns, to determine the impact of these parameters on the accuracy of microvessel density estimates. The same specimen was scanned in a whole-body EID CT and PCD CT system and images reconstructed with 600 and 250 micron slice thicknesses, respectively. Fraction of tissue volume that is filled with opacified microvessels was determined by first subtracting the mean background attenuation value from all voxels, and then by summing the remaining attenuation. Results: Microvessel density data were normalized to the value measured at 20 µm voxel size, which was considered reference truth for this study. For emulated micro-CT voxels up to 260 µm, the microvessel density was underestimated by at most 11{\%}. For whole-body EID CT and PCD CT, microvessel density was underestimated by 9.5{\%} and overestimated by 0.1{\%}, respectively. Conclusion: Our data indicate that microvessel density can be accurately calculated from the larger detector pixels used in clinical CT scanners by measuring the increase of CT attenuation caused by these opacified microvessels.",
keywords = "Computed tomography (CT), CT image voxel size, Detector pixel size, Microvessel, Spatial resolution",
author = "Mahya Sheikhzadeh and Vercnocke, {Andrew J.} and Shengzhen Tao and Kishore Rajendran and Shuai Leng and Ritman, {Erik L.} and McCollough, {Cynthia H}",
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T1 - Impact of Effective Detector Pixel and CT Voxel Size on Accurate Estimation of Blood Volume in Opacified Microvasculature

AU - Sheikhzadeh, Mahya

AU - Vercnocke, Andrew J.

AU - Tao, Shengzhen

AU - Rajendran, Kishore

AU - Leng, Shuai

AU - Ritman, Erik L.

AU - McCollough, Cynthia H

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N2 - Rationale and Objectives: The purpose of this study was to determine the impact of effective detector-pixel-size and image voxel size on the accurate estimation of microvessel density (ratio of microvascular lumen volume/tissue volume) in an excised porcine myocardium specimen using microcomputed tomography (CT), and the ability of whole-body energy-integrating-detector (EID) CT and photon-counting-detector (PCD) CT to measure microvessel density in the same ex vivo specimen. Materials and Methods: Porcine myocardial tissue in which the microvessels contained radio-opaque material was scanned using a micro-CT scanner and data were generated with a range of detector pixel sizes and image voxel sizes from 20 to 260 microns, to determine the impact of these parameters on the accuracy of microvessel density estimates. The same specimen was scanned in a whole-body EID CT and PCD CT system and images reconstructed with 600 and 250 micron slice thicknesses, respectively. Fraction of tissue volume that is filled with opacified microvessels was determined by first subtracting the mean background attenuation value from all voxels, and then by summing the remaining attenuation. Results: Microvessel density data were normalized to the value measured at 20 µm voxel size, which was considered reference truth for this study. For emulated micro-CT voxels up to 260 µm, the microvessel density was underestimated by at most 11%. For whole-body EID CT and PCD CT, microvessel density was underestimated by 9.5% and overestimated by 0.1%, respectively. Conclusion: Our data indicate that microvessel density can be accurately calculated from the larger detector pixels used in clinical CT scanners by measuring the increase of CT attenuation caused by these opacified microvessels.

AB - Rationale and Objectives: The purpose of this study was to determine the impact of effective detector-pixel-size and image voxel size on the accurate estimation of microvessel density (ratio of microvascular lumen volume/tissue volume) in an excised porcine myocardium specimen using microcomputed tomography (CT), and the ability of whole-body energy-integrating-detector (EID) CT and photon-counting-detector (PCD) CT to measure microvessel density in the same ex vivo specimen. Materials and Methods: Porcine myocardial tissue in which the microvessels contained radio-opaque material was scanned using a micro-CT scanner and data were generated with a range of detector pixel sizes and image voxel sizes from 20 to 260 microns, to determine the impact of these parameters on the accuracy of microvessel density estimates. The same specimen was scanned in a whole-body EID CT and PCD CT system and images reconstructed with 600 and 250 micron slice thicknesses, respectively. Fraction of tissue volume that is filled with opacified microvessels was determined by first subtracting the mean background attenuation value from all voxels, and then by summing the remaining attenuation. Results: Microvessel density data were normalized to the value measured at 20 µm voxel size, which was considered reference truth for this study. For emulated micro-CT voxels up to 260 µm, the microvessel density was underestimated by at most 11%. For whole-body EID CT and PCD CT, microvessel density was underestimated by 9.5% and overestimated by 0.1%, respectively. Conclusion: Our data indicate that microvessel density can be accurately calculated from the larger detector pixels used in clinical CT scanners by measuring the increase of CT attenuation caused by these opacified microvessels.

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KW - Microvessel

KW - Spatial resolution

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