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Objective To explore the clinical value of dual-source CT (DSCT) dual-energy imaging for in vivo diagnosis of gallstone composition. Methods Totally 200 patients with gallstone undergoing cholecystectomy were collected. DSCT dual energy examination was performed preoperatively to analyze the detection rate of 80 kV and 140 kV images for gallbladder negative stones. Taken the results of micro-infrared spectroscopy as golden standards, the 80 kV images CT value, 140 kV images CT value, CT value difference and CT value ratio among different stone composition were compared. The diagnostic efficacy of each indicator in differentiating cholesterol from non-cholesterol gallstone was calculated using ROC curves. Results The detection rate of 80 kV images, 140 kV images and the combined application of both for gallbladder negative stones was 88.89% (80/90), 76.67% (69/90) and 100% (90/90), respectively. The 80 kV images CT value, 140 kV images CT value, CT value difference and CT value ratio of cholesterol composition were all lower than those of bilirubin calcium and rare composition (all P0.05). Taken 62 HU and -2 HU as the threshold of 80 kV images CT value and CT value difference, the sensitivity and specificity in diagnosis of cholesterol and non-cholesterol composition stones were both 100%. Conclusion DSCT dual-energy imaging can be used in accurate identification of gallbladder cholesterol gallstones and non-cholesterol gallstones.
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Objective: To explore the value of spectral CT in differentiating pure and impure cholesterol stones. Methods: Spectral CT was used to scan in vitro gallstones, and infrared spectroscopy spectrum was used to observe the composition and classification of gallstones. ROIs were outlined in the axial, coronal and sagittal maximum planes of gallstones. Spectral CT indexes, including spectral curves, CT value, CT slope, effective atomic number (Zeff) and calcium-water ratio (CWR)) of the stones were acquired. Mann-Whitney U test was used to analyze the differences of parameters among different gallstone groups and subgroups. ROC curve was used to determine the diagnostic threshold, sensitivity, specificity, positive predictive value and negative predictive value of pure and impure cholesterol stone group. Results: There were significant differences of CT parameters between pure and impure cholesterol stone groups (all P0.05). Conclusion: The parameters of pure and impure cholesterol stones have good diagnostic efficacies. There are differences of energy spectrum curves of gallstones with different compositions.
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Objective To analyze the impact of dual energy monochromatic reconstructions (50-160 keV) on coronary calcified plaque stenosis quantification in a cardiac phantom with the real stenosis as standard of reference.Methods Signal-to-noise(SNR)and contrast-to-noise ratios(CNR)were calculated. In conventional 120 kV coronary CT angiography (CCTA) images as well as 12 monochromatic series(50-160 keV),luminal narrowing of calcified plaque was measured and compared to the real stenosis. Bland-Altman plots were performed to analyze the correlation of reference standard with conventional 120 kV and 12 monochromatic series (50-160 keV). The sensitivity, specificity, and accuracy of CCTA for detection of≥50% stenosis were calculated and receiver operating characteristic(ROC)curve was analyzed with the real stenosis as reference standard.Results The SNR and CNR were decreased with the increase of keV from 70 keV.The SNR and CNR of monochromatic imaging were lower compared with conventional 120 kV images(SNR:76.4±16.1;CNR:274.7±54.1)(P<0.05).The Bland-Altman plots presented a smaller measurement bias towards 90-160 keV than conventional 120 kV, and smallest measurement bias was revealed in 100-130 keV imaging(100-130 keV:bias 17.2% vs 120 kV:21.4%).Using the stenosis≥50% as cut-off value, the specificity were higher in the monochromatic series (70-160 keV) than conventional 120 kV CCTA.The specificity(75.0%)were the highest in the 120 keV and 130 keV images.The area under the ROC curve(AUC)of 90-130 keV(0.991-0.995)was higher than that in conventional 120 kV imaging (0.990). Conclusions The use of monochromatic imaging improves the overall accuracy of stenosis evaluation in coronary calcified plaques. Reconstructions at 100-130 keV for calcified lesions yielded the optimal results.
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PurposeTo analyze the urinary stone chemical composition using dual source CT (DSCT) dual energy imaging.Materials and MethodsNinety-seven stone samples with known chemical composition were placed in fresh swine kidneys and examined with DSCT dual energy scan, including 55 calcium oxalate stones, 13 hydroxyapatite stones, 9 uric acid stones, 4 cystine stones, 2 struvite stones and 14 mixed stones. The mean attenuation values and dual energy index (DEI) were measured at 80 kV and 140 kV. The stone composition was analyzed to determine the sensitivity, specificity and accuracy.ResultsDual energy analysis showed 59 calcium oxalate stones, 11 hydroxyapatite stones, 9 uric acid stones, 4 cystine stones and 14 mixed stones. 2 hydroxyapatite stones were erroneously marked as calcium oxalate stones and 2 struvite stones as calcium oxalate stones. The accuracy was 95.88% (93/97). The difference CT value at 80 kV and 140 kV and DEI value were statistically significant (P<0.05). The sensitivity for detecting calcium oxalate stones, hydroxyapatite stones, uric acid stones and cysteine stones were 100.00%, 84.60%, 100.00% and 100.00%, respectively; with specificity of 85.70%, 100.00%, 100.00% and 100.00%, respectively; and the accuracy were 95.18%, 97.59%, 100.00% and 100.00%, respectively.ConclusionDSCT dual energy imaging accurately analyzes the chemical composition of urinary stone in vitro, which provides important clinical value in analyzing the urinary stonesin vivo.
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Objective To investigate the principle and its clinical initial application of the dual-energy imaging with the dual-source CT and increase the realization of it. Methods According to the research results of the dual-energy imaging with the dual-source CT and the course of development of the dual-energy imaging to analyze and summarize the basis radiological physics, the principles, the correlation parameters and the clinical initial application of the dual -energy imaging with the dual -source CT. Results The dual -energy imaging with the dual -source CT is different from other common dual-energy imaging, it has its own special feature. Conclusion According to the analysis of the dual-energy imaging with the dual-source CT, greatly increase the realization of the dual-energy imaging with the dual-source CT.