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Objective To explore the clinical value of dual-energy CT lung perfusion imaging and perfusion scintigraphy in acute pulmonary embolism (PE) rabbit models. Methods Acute PE models were established in 20 rabbits with femoral vein injection of sponge as embolus materials, and 4 rabbits were injected saline as control group. Two hours after embolization, dual-energy CT and perfusion scintigraphy imaging were performed respectively. Taking the pathologicall findings as the reference standards, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of both imaging methods were compared. CT values and enhancement degree (overlay value) of the embolic areas and normal pulmonary parenchyma were measured in DEPI image after embolization. Results Normal lung was color-coded as homogeneously yellowish red, perfusion scintigraphy displayed rarefaction or absence. The sensitivity, specificity, PPV, NPV of DEPI was 100%, 97.50%, 95.24%, 100%, and of perfusion scintigraphy was 67.50%, 81.25%, 64.29%, 83.33%, respectively. Increased CT values and overlay values of embolism areas in DEPI images were lower than those of normal pulmonary parenchyma (P<0.05). Conclusion DEPI has higher sensitivity and specificity than perfusion scintigraphy for detection of pulmonary emboli in an acute PE rabbit models.
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Objective Different grades of glioma lead to different clinical course,treatments and prognosis,thus it is important to predict histological grades of glioma preoperatively.18F-FDG PET/CT imaging and MR perfusion imaging is considered a promising method to evaluate glioma,and the present study was to evaluated the contribution of 18F-FDG PET/CT imaging and MR perfusion imaging in grading intracranial glioma.Methods Eighteen consecutive patients with suspected primary brain glioma underwent 18F-FDG PET/CT scanning and MR perfusion scanning in our hospital.To evaluate the relative sensitivity among standardized uptake value (SUV),L/W,and rCBV,the PET/CT imaging were analyzed,and the SUV and Lesion-to-white matter ratio (L/W) were calculated.The rCBV ratios of lesions were calculated relative to the region of interest (ROI) values in contra lateral normal white matter.Results Eighteen brain gliomas were confirmed by pathologic diagnosis,including 7 WHOⅡ tumors,6 WHOⅢ tumors,and 5 WHOⅣ tumors.SUV and rCBV could not differentiate between WHOⅡ tumor and WHOⅢ tumor,however significant difference could be found among the three using L/W.Conclusion 18F-FDG PET/CT imaging and MR perfusion imaging could offer more diagnostic information than conventional MRI.All of the three semiquantitative data offer some contribution in grading intracranial gliomas,and L/W might be the best one.
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Objective: To investigate the value of positron emission tomography/computerized tomography(PET/CT) with fluorine-18-labeled fluorodeoxyglucose(18FDG) for gastric carcinoma.Methods: Thirty-two patients(25 males,7 females,aged 31-82 years) suspected of gastric carcinoma underwent whole-body PET/CT after taking in 600 ml of water to distend the gastral cavity.The maximal standard uptake value(SUVmax) of the region of interest(ROI) in PET and the maximum width of the gastric wall in CT were analyzed.Pathological specimens were obtained from all the patients during surgery or gastroscopy.Results: 18FDG PET/CT found gastric carcinoma in 24 of the patients.The rates of positive and negative prediction and the accuracy of PET/CT in the diagnosis of the disease were 92.3%,100% and 93.8%.SUVmax was positively correlated with the maximum width of the gastric wall,but they exhibited no statistically significant differences between the patients with involved lymph nodes and those without.Based on the PET/CT findings,the 24 gastric carcinoma patients were clinically classified as follows: 9 in stage Ⅰ,1 in stage Ⅰ-Ⅱ,3 in stage Ⅱ,1 in stage Ⅲ and 10 in stage Ⅳ.Conclusion: 18FDG PET/CT is highly valuable for gastric carcinoma in its diagnosis,the evaluation of its biological behavior and determination of its treatment strategies.