| Purpose To explore the diagnostic performance of different spectral images obtained from dual-layer spectral detector CT for detecting late iodine enhancement(LIE)compared with 3TMRIMethods Patients with having or suspected of myocardiopathy underwent cardiac LIE using dual-layer spectral detector CT and late gadolinium enhancement(LGE)MRI.CT-LIE images were constructed as iodine density map,40 to 80 keV monoenergetic images with 10 keV increment and conventional CT image.The subjective and objective image quality based on these images were compared.The diagnostic performance of CT-LIE based on these images were evaluated with MRI as the reference standard.Results 56 patients with 896 myocardial segments were finally enrolled in our study.Among 56 patients,38 patients with 302 segments had LGE on cardiac MRI.The subjective image quality score of iodine density map and 40-50 keV images were not significantly different(all P>0.05),but the score of these images were higher than that in 60-80keV images and conventional CT image(all P<0.001).The contrast to noise ratio(CNR)of iodine density map and 40-50 keV images were not significantly different(all P>0.05),but the CNR of these images were higher than that in 60-80keV image and conventional CT image(all P<0.001).On per-segment analysis,the accuracy,sensitivity,specificity,positive predictive value,and negative predictive value of iodine density map in detecting late enhancement were 85.0%,84.4%,85.4%,74.6%,and 91.5%.The receiver operating characteristic(ROC)curve analysis showed that the area under the curve(AUC)of iodine density map(AUC=0.932)was superior to those of monoenergetic images(40keV AUC=0.918;50keVAUC=0.904;60keV AUC=0.856;70keVAUC=0.833;80keV AUC=0.774)and conventional CT image(AUC=0.802)compared with MRI(all P<0.001).Conclusions Iodine density map and 40-50 keV images derived from dual-layer spectral CT improve image quality of myocardial delayed enhancement and the iodine density map provides high diagnostic performance in identifying myocardial delayed enhancement.Diagnostic performance of spectral reconstruction in detecting late iodine enhancement using dual-layer spectral detector CT:Comparison with 3-T MRIFeasibility of extracellular volume quantification using dual-layer spectral detector computed tomographyPurpose To evaluate the segmental myocardial extracellular volume(ECV)fraction and to define a threshold ECV value that can be used to distinguish positive late gadolinium enhancement(LGE)segments from negative myocardial segments using dual-layer spectral detector computed tomography,with magnetic resonance imaging(MRI)as a reference.Methods Subjects having or suspected of cardiac disease underwent both late iodine enhancement on CT(CT-LIE)scanning and late gadolinium enhancement on MRI(MRI-LGE)scanning.Global and segmental EC Vs of the left ventricle were measured by CT and MRI images.According to the location and pattern of delayed enhancement on MRI image,myocardial segments were classified into three groups:ischemic LGE segments(Group A),nonischemic LGE segments(Group B)and negative LGE segments(Group C).The correlation and agreement between CT-ECV and MRI-ECV were compared on a per-patient and per-segment basis.Receiver operating characteristic(ROC)curve analysis was performed to establish a threshold for late iodine enhancement detection.Results 56 patients were fmally enrolled in our study.Among the 56 patients,896 segments were analyzed;of these 73 segments were in Group A,229 segments were in Group B and 594 segments were in Group C.There was no significant difference between CT-ECV(28.7%;26.5-31.9)and MRI-ECV(28.4%;26.6-32.2)in the per-subject analysis(P=0.383).A good correlation was seen between CT-ECV and MRI-ECV(r=0.970,P<0.001).Bland-Altman analysis between CT-ECV and MRI-ECV showed a small bias(-0.1%),with 95%limits of agreement of-5.7%to 5.5%.On segmental analysis,CT-ECV in Group C(27.0%;24.9-28.9)was significantly lower than that in Group A(33.2%;30.7-36.3)and Group B(34.9%;32.3-39.8)(all P<0.001).Good correlations were seen between CT-ECV and MR-ECV for all groups(Group A:r=0.920;Group B:r=0.936 and Group C:r=0.799)(all P<0.001).Bland-Altman analysis between CT-ECV and MR-ECV showed a small bias in all three groups:Group A-2.1%(95%limits of agreement:-11.3,7.1),Group B-0.6%(95%limits of agreement:-13.1,11.9)and Group C 1.0%(95%limits of agreement:-12.7,14.7).CT-ECV could differentiate between LGE-positive and LGE-negative segments with 83.1%sensitivity and 93.3%specificity at a cutoff of 30.97%;the area under the curve of ROC was 0.957.Conclusions ECV values derived from dual-layer CT showed good correlation and agreement with MRI findings,and CT-ECV provided high diagnostic accuracy for discriminating between LGE-positive and LGE-negative segments.Thus,CT-ECV could be an alternative tool for the characterization of myocardial tissue.Quantitative evaluation of extracellular volume in heart failure using dual-layer spectral detector CT:a comparison with 3T MRIPurposes To evaluate extracellular volume(ECV)using dual-layer spectral detector CT in patients with heart failure compared with MR image.Methods 27 patients with heart failure in our hospital underwent both late iodine enhancement on CT scanning and late gadolinium enhancement on MRI scanning from July 2019 to January 2021.According to percentage of hyper-enhanced area on cardiac MR image,myocardial segments were classified into 3 groups:0-4%(group A),5-49%(group B)and 50%-100%(group C).The correlation and agreement between CT-ECV and MRI-ECV were compared in a per-patient and per-segment.Results Among the 27 patients,432 segments with 199 segments in group A,151 segments in group B and 82 segments in group C were analyzed.The mean of CT-ECV and MRI-ECV was 32.25(28.04,34.28)%and 32.27(28.35,34.77)%,respectively.A good correlation was seen between CT-ECV and MRI-ECV(r=0.969,P<0.001).Bland-Altman analysis between CT-ECV and MRI-ECV showed a small bias(0.4%),with 95%limits of agreement of-6.9%to 7.8%.Mean segmental CT-ECV was 28.23(26.18,29.92)%in group A,33.29(30.16,35.96)%in group B and 40.22(34.06,46.70)%in group C.There was statistically significant difference in ECV among three groups(all P<0.001).A good correlation between CT-ECV and MRI-ECV was found in group A(r=0.614,P<0.001),group B(r=0.852,P<0.001)and group C(r=0.953,P<0.001).Bland-Altman analysis between CT-ECV and MRI-ECV showed a small bias 2%(95%limits of agreement:-17.6%,21.6%)in group A,a small bias-0.4%(95%limits of agreement:-13.8%,12.9%)in group B and a small bias-1.8%(95%limits of agreement:-17.4%,13.9%)in group C.Conclusions ECV derived from CT and MRI showed stronger correlation with higher delayed enhancement percentage on myocardial segment.CT-ECV could be an alternative tool for characterizing myocardial tissue. |
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