Diagnostic Value of Low-Dose 256-Slice Spiral CT Angiography, MR Angiography, and 3D-DSA in Cerebral Aneurysms.

OBJECTIVE: To evaluate the diagnostic value of low-dose 256-slice CT angiography (CTA), MR angiography (MRA), and three dimensional-digital subtraction angiography (3D-DSA) in cerebral aneurysms. METHODS: CTA, MRA, and 3D-DSA were performed in all enrolled patients to explore the diagnostic significance of the three different examinations. RESULTS: There were 92 aneurysms confirmed during DSA and surgery in 79 patients. The diagnostic coincidence rates of DSA, CTA, and MRA were 96.7%, 89.1%, and 86%, respectively. The diagnostic coincidence rates of CTA and MRA were lower than those of DSA. The detection rate of CTA for aneurysms less than 3 mm in diameter was higher than that of MRA. CONCLUSION: CTA, DSA, and MRA have their own advantages and disadvantages in the diagnosis of cerebral aneurysms. They all have the diagnostic value for aneurysms.

Diagnostic value of 64-slice spiral computed tomography imaging of the urinary tract during the excretory phase for urinary tract obstruction.

The present study aimed to assess the diagnostic value of 64-slice spiral computed tomography (CT) imaging of the urinary tract during the excretory phase for urinary tract obstruction. CT imaging of the urinary tract during the excretory phase was performed in 46 patients that had been diagnosed with urinary tract obstruction by B-mode ultrasound imaging or clinical manifestations. It was demonstrated that out of the 46 patients, 18 had pelvic and ureteral calculi, 12 cases had congenital malformations, 3 had ureteral stricture caused by urinary tract infection and 13 cases had malignant tumors of the urinary tract. The average X-ray dose planned for the standard CT scan of the urinary tract group 1 was 14.11±5.45 mSv, while the actual X-ray dose administered for the CT scan during the excretory phase group 2 was 9.01±4.56 mSv. The difference between the two groups was statistically significant (t=15.36; P<0.01). The results of the present study indicate that CT scanning of the urinary tract during the excretory phase has a high diagnostic value for urinary tract obstruction.

Optimization of the scanning technique and diagnosis of pulmonary nodules with first-pass 64-detector-row perfusion VCT.

OBJECTIVE: The aims of this study were to optimize the scanning technique of first-pass 64-detector-row perfusion volume computed tomography imaging, to evaluate the effectiveness and stability of this scan protocol, and lastly to evaluate the differential diagnosis ability of perfusion imaging in solitary pulmonary nodules (SPNs). METHODS: A total of 144 patients with SPNs underwent perfusion scan with 64-slice spiral CT scanner. The CT perfusion imaging was analyzed for time-density curve, perfusion parametric maps, and the respective perfusion parameters. We then analyzed the main factors concerning the imaging quality and evaluated the effectiveness of scan protocol by determining the receiver operating characteristic (ROC) curve, diagnostic efficacy, and odds ratio as well as the stability of scan protocol by consistency analysis. Immunohistochemical findings of microvessel density measurement and vascular endothelial growth factor expression were evaluated. RESULTS: The total sensitivity, specificity, accuracy, positive predictive value, negative predictive value, likelihood ratio, and the area under ROC curve during 5-45-s scan period were 78.95%, 82.4%, 80.6%, 83.3%, 77.8%, 4.620, 0.280, and 0.840, respectively, and Kappa value was 0.894. The diagnostic efficacy of CT pulmonary perfusion was significantly higher than during 0-40-s scan period. The parameter values in different nodules were different. CONCLUSION: The optimized 5-45-s scan period of CT pulmonary perfusion imaging is effective in pathologic diagnosis and has good stability, worthy of being popularized. Lung perfusion CT could be a promising and feasible method for differentiation of SPNs.

Functional CT for assessment of early vascular physiology in liver tumors.

BACKGROUND: CT perfusion has been reported to have great advantages in detecting hepatic diseases. However, currently there are no studies showing the potential value of multi-slice CT perfusion with the deconvolution model method in diagnosing early hemodynamic changes caused by liver tumors. This study was undertaken to determine if early hemodynamic changes caused by liver tumors can be depicted with the perfusion imaging of multi-slice CT. METHODS: Ten New Zealand white rabbits before and after VX2 liver tumor inoculation served as the experimental animals. Ten normal rabbits served as controls. All underwent multi-slice CT perfusion for the measurement of hepatic blood flow (HBF), hepatic blood volume (HBV), mean transit time (MTT), permeability of capillary vessel surface (PS) and hepatic artery index (HAI). RESULTS: With the exception of MTT, which decreased significantly at the tumor periphery, HBF, HBV, PS and HAI increased significantly compared with the surrounding normal tissue. All these changes occurred at days 5-9 after tumor inoculation. Statistically significant changes in these values were detected with tumor growth. CONCLUSIONS: The hemodynamic changes in the liver caused by rabbit VX2 liver tumor can be detected after tumor inoculation, and functional CT can evaluate the physiological characteristics of early tumor angiogenesis.