Application of dynamic contrast-enhanced magnetic resonance imaging in evaluating liver fibrosis / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the value of time-signal intensity curve (TIC) in dynamic contrast-enhanced magnetic resonance imaging (DEC-MRI) in the evaluation of liver fibrosis.</p><p><b>METHODS</b>Thirty-six consecutive patients and healthy volunteers were divided into 4 groups according to the stages of fibrosis, namely the normal group (n=9), mild fibrosis group (n=5), moderate to severe fibrosis group (n=7), and liver cirrhosis group (n=15). All the subjects underwent conventional and DEC-MRI, and the TIC was generated automatically to evaluate the peak height, TTP, MSI and MSD. The correlations between the TIC parameters and the stage of fibrosis were assessed. Receiver operating characteristic (ROC) curve analyses were conducted to evaluate the value of the TIC parameters in the evaluation of fibrosis stage.</p><p><b>RESULTS</b>Moderate but significant inverse correlations of the peak height, MSI, and to fibrosis stage were noted in these patients (P<0.05); the peak time was positively correlated to the fibrosis stage (P<0.05). In patients with a fibrosis stage ≥1, the AUC of the measured TIC parameters ranged from 0.747 to 0.783, with the MSD of the spleen had the highest AUC (0.783). For a fibrosis stage ≥3, the AUC of the indices ranged between 0.728 and 0.877, highest for liver MSI of the arterial phase, followed by the portal vein MSI, liver MSI of portal venous phase, liver MSD, splenic MSI of arterial phase and splenic MSD. In the diagnosis of liver cirrhosis, the AUC (range 0.742-0.821) decreased in the order of liver MSI of the portal venous phase, liver MSD, liver MSI of the arterial phase, the portal vein MSI, splenic MSI of the arterial phase and splenic MSD.</p><p><b>CONCLUSION</b>TIC of DEC-MRI can be used to evaluate hemodynamic changes in the liver, and may serve as a practical non-invasive functional imaging modality for assessing the severity of liver fibrosis.</p>

Value of multi-slice spiral CT in the diagnosis and therapeutic effect evaluation of gastrointestinal stromal tumors / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the CT manifestations of gastrointestinal stromal tumors, and explore the value of CT in the diagnosis and therapeutic effect evaluation of these tumors.</p><p><b>METHODS</b>A retrospectively analysis of the medical imaging data was conducted in 39 cases of gastrointestinal stromal tumors confirmed by surgery and pathology in comparison with the pathological findings.</p><p><b>RESULTS</b>Of the 39 patients with gastrointestinal stromal tumors, 2 had esophageal stromal tumors, 23 had gastric stromal tumor, 7 had duodenal stromal tumor, 4 had jejunal stromal tumors, 2 had ileal stromal tumors, and 1 had colon stromal tumor. Twenty-five patients were found to have highly malignant tumors, and 11 had low-grade tumors, with the other 3 having tumors of unidentifiable nature. CT displayed exogenous or endogenous mass in these cases, and the tumors had a maximum diameter ranging from 3 to 45 cm (<5 cm in 12 cases and >or=5 cm in 27 cases). Of the 27 cases with a tumor diameter over 5 cm, 23 had malignant stromal tumors, and the tumor mass showed heterogeneous density with central necrosis and cystic and the solid portion of the tumor exhibited mild to moderate enhancement. Six patients were found to have intratumoral punctate calcification, and 17 with malignant tumors showed high peripheral enhancement, with the solid portion of the tumors showing delayed enhancement. The 6 patients with unresectable tumors received chemotherapy resulting in significantly reduced tumor diameter and cystic and necrotic foci in the tumor.</p><p><b>CONCLUSION</b>Multi-slice spiral CT allows precise localization and qualitative assessment of gastrointestinal stromal tumors, and also helps in the evaluation of the therapeutic effect.</p>