课件：肾上腺肿瘤影像学诊断策略.ppt

* Chemical Shift Imaging is to measure SI loss in opposed phase compared to in phase images The cutoff value is 10-15% Sensitivity of 91% , specificity of 94-% Qualitative diagnosis is as good as quantitative assessment * This is a adnomas showed obvious SI loss on opposed phase images * And Adrenal metastastes donot loss SI * There are exception, Lipid-poor adenoma do not have SI loss, too * So the final imaging model is Functional imaging, they are Washout ratio by DCE CT/MRI, CT perfusion ,PET-CT, MR spectrography and diffusion weighted is under investigated * IV contrast medium “wash out” much faster for adenomas than nonadenomas Percentage washout ratios APW(absolute percentage washout ) (Enhanced CT value- Delayed CT value)/(Enhanced CT value- unenhanced CT value) ×100% RPW relative percentage washout RPW =(Enhanced CT value- Delayed CT value)/ Enhanced CT × 100% Most accepted threshold 15-minute delayed scan 40% for RPW or 60% for APW Also recommended 10-minute delay scan RPW 50% Nearly 100% sensitive and specific ! * Type I Delayed enhanced Neurogenic tumors Type II Rapid washout Adenomas Type III Moderate washout Intimidate Type IV Slow washout Malignant tumors * BV can be used differentiating adenomas from nonadenomas BV can be used differentiating adenomas from nonadenomas * Metabolically active malignant lesions trapping 18F-FDG intracellularly, whereas most benign lesions do not Very early metastates could be detected Sensitivity 93%~ 100% and specificity 95% Some adenomas, inflammatory lesions demonstrate slightly increased uptake Necrotic or hemorrhagic malignant lesions may cause false-negative findings * DWI could not differentiate benign adrenal lesions from malignant lesions DWI could not help in distinguishing lipid-poor adenomas and non adenomas No discrepancies of ADC values among them * * [诊断与鉴别诊断] 临床考虑为嗜铬细胞瘤时，若超声、CT或MRI检查发现肾上腺较大肿块并具有上述表现，可诊断为肾上腺嗜铬细胞瘤。 　　若肾上腺区未发现异常，则应检查其它部位，有可能查出异位嗜铬细胞瘤，后者常位于腹主动脉旁，表现类似肾上腺嗜铬细胞瘤。 肾上腺皮质