腹盆部巨大淋巴结增生症的CT及MRI表现和不同病理类型能谱CT特征

CT and MRI manifestations of abdominopelvic Castleman's disease and spectral CT appearances of different pathological patterns

目的探讨腹盆部巨大淋巴结增生症(Castleman病)的CT和MRI特征性表现,并对不同病理类型进行能谱CT分析。方法 13例患者均行CT平扫+动态增强检查,启用GSI viewer软件,在动脉期及门静脉期图像上综合观察,然后在动脉期图像上测量相关数据,其中10例患者采用3.0TGE Discovery MRI扫描仪行T1WI、T2WI横轴面及T2脂肪抑制轴位平扫,5例行T1WI动态三期增强。结果 CT平扫9例均呈类圆形等密度肿块,轻度分叶,边缘光滑清晰,4例肿块密度不均并伴有斑点状钙化,动态增强9例均见动脉期显著强化、门静脉期、延迟期持续均匀强化,4例伴有钙化的肿块呈不均匀持续强化,2例肿块周围可见子灶。10例行MRI检查,平扫呈等或稍长T2、长T2信号,T2脂肪抑制呈明显高信号,5例增强后病灶呈中度强化,瘤灶内均可见中央条索状及小片状低信号区。本组病例中均为局限型,7例位于腹膜后,3例位于肠系膜区,3例位于盆腔,其中1例合并左侧卵巢纤维瘤。10例病理类型为透明血管型,3例为浆细胞型。综合混合能量图像、单能量图像及碘基图图像三种图像能使病灶显示更清楚,不同病理类型在不同keV下其衰减程度不同,其能谱曲线图表现不同。在碘基图及水基图上可见10例透明血管型碘含量明显增高,而3例浆细胞型碘含量明显低于透明血管型,但含水量稍高于前者。结论腹盆部Castleman病具有一定特征性,CT动态增强及MRI对透明血管型诊断不难,而浆细胞型Castleman病临床表现复杂,影像学表现不典型,术前诊断仍较困难,需结合病理学检查,但能谱CT分析有助于病理分型。

Objective To analyze CT and MRI manifestations of abdominopelvic Castleman＇ s disease, and to make spectral CT analysis on different pathological patterns. Methods Plain and dynamic contrast-enhanced CT scans were performed in 13 patients： GSI viewer software was enabled to fully observe on AP and PVP images, followed by measurement of related data on AP images. Of them, horizontal T1-and T2-weighted and axial fat-suppressed T2-weighted MRIs were performed in 10 patients by GE Discovery MRI 3.0T scanner, and triphasic dynamic contrast-enhanced T1 -weighted MRI in 5. Results Plain CT scans revealed mildly-lobu- lated quasi-circular isodense masses with smooth, well defined margins in 9 patients, and nonhomogeneous density with stippled calcification in 4; dynamic contrast-enhanced CT scans revealed significant AP enhancement and continuously homogeneous PVP and DP enhancement in 9, calcification with continuously nonhomogeneous enhancement in 4, and satellite nodules around masses in 2. On plain MRI, l0 patients were iso-or slightly hyperintense, or hyperintense on T2WI with significant hyperintensities on T2- weighted fat-suppression images ; on contrast-enhanced CT, lesions in 5 patients showed moderate enhancement with centrally stripe and small patchy hypointensities within tumor lesions. Of those localized cases, 7 were located in the retroperitoneum, and 3 in the mesenterium, 3 in the pelvic cavity （ 1/3 complicated with left ovarian fibroma）. There were l0 hyaline-vascular type and 3 plasma cell type patients pathologically. Synthesis of 3 different images （ mixed-energy, single-energy and iodine-based contrast images） could depict lesions more clearly; for different pathological patterns, the degree of attenuation and the spectral curve varied with the keV value. Both iodine-and water-based images depicted a notable increase in iodine content in the l0 hyaline-vascular type patients, with notably lower iodine content in the 3 plasma cell type patients than in those l0 ones but slightly higher water content than the former. Conclusion Abdominopelvic Castleman＇ s disease is characteristic on both CT and M RI. Diagnosis of hyalinevascular type is confirmed easily, but as for plasma cell type, pathological examinations are needed due to its complicated clinical manifestations, atypical imaging findings and difficult preoperative diagnosis. However, spectral CT analysis contributes to the pathological type.