Clinical feasibility of using effective atomic number maps derived from non-contrast spectral computed tomography to identify non-calcified atherosclerotic plaques: a preliminary study.

Background To assess the clinical feasibility of using effective atomic number (Zeff) maps derived from non-contrast-enhanced computed tomography (NCECT) scans obtained by dual-layer spectral computed tomography (DLCT) to identify non-calcified atherosclerotic plaques. Methods A total of 37 patients with 86 non-calcified atherosclerotic plaques confirmed by contrast-enhanced CT (CECT) were enrolled in this retrospective study. Both spectral-based-images (SBI) and conventional images (CI) were reconstructed from NCECT and CECT scans. The presence of plaques on NCECT Zeff maps and CIs were independently assessed by 2 radiologists. In CECT scans, plaques and regions of interest (ROIs) in vessel lumens were assessed with CT attenuation and Zeff values, and the proportion of plaques was determined as Area (plaque)/Area (vessel). The CT and Zeff values for plaques and blood were recorded from both CECT and NCECT scans. Contrast-to-noise ratios (CNRs) of the plaques were calculated and compared using CT attenuation and Zeff values. Finally, interobserver agreement was evaluated. Results A total of 47 of the 86 (54.7%) plaques were identified on Zeff map images derived from the NCECT scans while only 7 (8.1%) plaques were identified on the CI. There was no significant difference between the mean vessel ROI area measured on CIs and that measured on Zeff map images (502.19 vs. 498.14 mm2; P=0.28), while the mean plaque ROI area was larger (81.45 vs. 75.46 mm2). The observer consensus of vessel and plaque ROI area measurements using both methods was excellent, with interclass correlation coefficients (ICCs) of 0.99 and 0.94, respectively. For the 7 plaques detected both by NCECT CI and Zeff mapping, the CT attenuation and Zeff blood values were both larger than the plaque values [42.00 vs. 25.67 Hounsfield unit (HU); 7.33 vs. 7.19 HU; both P<0.05]; the plaque ROI area measurement on the NCE Zeff map was smaller than that on the CE CI (48.73 vs. 77.76 mm2), but was much larger than that on the NCE CI (18.39 mm2). For all 47 plaques detected by NCE Zeff mapping, the CT attenuation and Zeff values of blood and plaques on the NCECT images showed no significant differences (42.53 vs. 35.14 HU; P=0.18; 7.32 vs. 7.31, P=0.71); however, the CNR of Zeff was significantly higher than the CT attenuation value (1.69 vs. 1.12; P<0.05) derived from the NCECT scans. Inter-reviewer agreement was good (ICC =0.78). Conclusions Zeff map images derived from NCECT SBI with DLCT provide a potentially feasible approach for identifying non-calcified atherosclerotic plaques, which might be clinically useful for the screening of asymptomatic at-risk patients.

[1]  Yue Ma,et al.  The optimal monoenergetic spectral image level of coronary computed tomography (CT) angiography on a dual-layer spectral detector CT with half-dose contrast media. , 2020, Quantitative imaging in medicine and surgery.

[2]  D. Maintz,et al.  Technical background of a novel detector-based approach to dual-energy computed tomography. , 2020, Diagnostic and interventional radiology.

[3]  D. Maintz,et al.  Low-Dose Characterization of Kidney Stones Using Spectral Detector Computed Tomography: An Ex Vivo Study , 2018, Investigative radiology.

[4]  T. Merchant,et al.  Accuracy of electron density, effective atomic number, and iodine concentration determination with a dual‐layer dual‐energy computed tomography system , 2018, Medical physics.

[5]  P. Rajiah,et al.  Benefit and clinical significance of retrospectively obtained spectral data with a novel detector-based spectral computed tomography - Initial experiences and results. , 2018, Clinical imaging.

[6]  Y. Yamashita,et al.  Advanced parametric imaging for evaluation of Crohn's disease using dual-energy computed tomography enterography , 2018, Radiology case reports.

[7]  Hirokazu Saito,et al.  Usefulness and limitations of dual-layer spectral detector computed tomography for diagnosing biliary stones not detected by conventional computed tomography: a report of three cases , 2018, Clinical Journal of Gastroenterology.

[8]  Kai Mei,et al.  Assessment of quantification accuracy and image quality of a full‐body dual‐layer spectral CT system , 2017, Journal of applied clinical medical physics.

[9]  J. Leipsic,et al.  Update on Cardiovascular Applications of Multienergy CT. , 2017, Radiographics : a review publication of the Radiological Society of North America, Inc.

[10]  B. Merkely,et al.  Plaque imaging with CT-a comprehensive review on coronary CT angiography based risk assessment. , 2017, Cardiovascular diagnosis and therapy.

[11]  Y. Yamashita,et al.  Clinical potential of retrospective on-demand spectral analysis using dual-layer spectral detector-computed tomography in ischemia complicating small-bowel obstruction , 2017, Emergency Radiology.

[12]  Terry K Koo,et al.  A Guideline of Selecting and Reporting Intraclass Correlation Coefficients for Reliability Research. , 2016, Journal Chiropractic Medicine.

[13]  R. Singh,et al.  DECT evaluation of noncalcified coronary artery plaque. , 2015, Medical physics.

[14]  C. McCollough,et al.  Dual- and Multi-Energy CT: Principles, Technical Approaches, and Clinical Applications. , 2015, Radiology.

[15]  J. Dehmeshki,et al.  CT Attenuation Values of Blood and Myocardium: Rationale for Accurate Coronary Artery Calcifications Detection with Multi-Detector CT , 2015, PloS one.

[16]  Fabian Bamberg,et al.  Coronary Computed Tomography Angiography Based Assessment of Endothelial Shear Stress and Its Association with Atherosclerotic Plaque Distribution In-Vivo , 2015, PloS one.

[17]  Hyuk-Jae Chang,et al.  Prevalence and Prognostic Implication of Non-Calcified Plaque in Asymptomatic Population with Coronary Artery Calcium Score of Zero , 2013, Korean circulation journal.

[18]  U. Schoepf,et al.  Can non-calcified coronary artery plaques be detected on non-contrast CT calcium scoring studies? , 2011, Academic radiology.

[19]  Mitchell M Goodsitt,et al.  Accuracies of the synthesized monochromatic CT numbers and effective atomic numbers obtained with a rapid kVp switching dual energy CT scanner. , 2011, Medical physics.

[20]  Marc Kachelrieß,et al.  Image-based dual energy CT using optimized precorrection functions: A practical new approach of material decomposition in image domain. , 2009, Medical physics.

[21]  R. Sacco,et al.  Atherosclerotic Disease of the Proximal Aorta and the Risk of Vascular Events in a Population-Based Cohort: The Aortic Plaques and Risk of Ischemic Stroke (APRIS) Study , 2009, Stroke.

[22]  C. McCollough,et al.  Quantitative imaging of element composition and mass fraction using dual-energy CT: three-material decomposition. , 2009, Medical physics.

[23]  Yujie Zhou,et al.  Identification and quantification of coronary atherosclerotic plaques: a comparison of 64-MDCT and intravascular ultrasound. , 2008, AJR. American journal of roentgenology.

[24]  D. Dey,et al.  Computer-aided detection and evaluation of lipid-rich plaque on noncontrast cardiac CT. , 2006, AJR. American journal of roentgenology.

[25]  Sanjiv Sharma,et al.  Non-invasive characterization of coronary artery atherosclerotic plaque using dual energy CT: Explanation in ex-vivo samples. , 2018, Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics.

[26]  Katia Parodi,et al.  Dual‐energy CT quantitative imaging: a comparison study between twin‐beam and dual‐source CT scanners , 2017, Medical physics.

[27]  P. Libby,et al.  Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 2-Volume Set, 9th Edition Expert Consult Premium Edition €“ Enhanced Online Features , 2011 .

[28]  R. A. Rutherford,et al.  Measurement of effective atomic number and electron density using an EMI scanner , 2004, Neuroradiology.