腹部肾上腺外嗜铬细胞瘤:双期增强的影像学诊断价值

目的:分析腹部肾上腺外嗜铬细胞瘤的影像学表现及其动态增强特征,以提高其诊断准确性.方法:经手术病理证实的腹部肾上腺外嗜铬细胞瘤15例,12例术前经螺旋CT和多排螺旋CT平扫、动脉期和门脉期扫描.对比剂分别采用欧乃派克和优维显,注射流率3 ml/s.3例经MR SE-T1WI,FSE-T2WI,GRE动态增强扫描,对比剂为马根优维显,注射流率1.5～2ml/s.仔细复习CT和MR扫描结果并和手术病理作回顾性对照分析.结果:15例腹部肾上腺外嗜铬细胞瘤中,副神经节瘤13例,异位嗜铬细胞瘤2例.良性12例,恶性3例.病灶分别位于腹膜后(1 3例)和肾内(2例).肿瘤直径4.3～12.0 cm,其中病灶直径＜5.0 cm 2个,5.0～10.0 cm 12个,＞10 cm1个;肿瘤境界清楚.肿瘤实质成分平扫、动脉期和门脉期CT值分别为32.6～55.1 HU(平均43.8 HU)、57.8～87.9 HU(平均77.3 HU)和72.4～115.6 HU (平均93.7 HU).MR T1WI为低信号,T2WI为显著高信号,MR动态增强强化方式与CT动态增强类似.肿瘤囊变、坏死和钙化常见.结论:腹部肾上腺外嗜铬细胞瘤包括副神经节瘤和异位嗜铬细胞瘤,异位嗜铬细胞瘤可位于肾内.肿瘤中等大小,囊变、坏死和钙化较常见,囊变的识别对诊断有很大帮助.MR T2WI为显著高信号,动态增强为进行性延迟强化.强化不典型者与腹膜后其他肿瘤难以鉴别.

Abdomen Extraadrenal Pheochromocytomas: Imaging Features of Dynamic Enhancement

Objective:Exploring dynamic imaging features of abdomen extraadrenal pheochromocytomas and evaluating its clinical value.Methods:12 of 15 patients with abdomen extraadrenal pheochromocytomas confirmed by surgical pathology underwent spiral CT plain scanning and two phases dynamic enhancement scanning before operation,contrast injection was done by using nonionic omnipaque at a flow rate of 3ml/s with a power injector,3 underwent MR SE-T1WI,FSE-T2WI,GRE dynamic enhancement with Magnevist as contrast.The CT and MR date was reviewed and analyzed retrospectively in comparison with surgical and pathological results.Results 13,2 of 15 cases with 3 malignancies and 12 benignancy were paragangliomas in retroperitoneal,ectopic pheochromocytomas in the left kidney respectively.The diameter of the tumors was 4.3~12.0cm with 2 cases <5.0cm,12 cases 5.0~10.0cm and 1 cases >10cm.The attenuation of the plain scans,two phases contrast scans was 32.6~55.1HU (with a mean value of 43.8HU),57.8~87.9HU (mean value 77.3HU),72.4~115.6HU (mean value 93.7HU) respectively.The tumor presented low middle signal intensity on SE T1-weighted imaging,obvious high signal intensity on FSE T2-weighted imaging and similar dynamic enhancement to CT.Cysts,necrosis,calcifications and hemorrhage in the lesions were common.Conclusion:The imaging features of the abdomen extraadrenal pheochromocytomas,which include paragangliomas,and ectopic pheochromocytomas are similar to that of adrenal pheochromocytomas.It is important for the radiologist to recognize the typical imaging appearance of dynamic scan because they can be mistaken for other retroperitoneal tumours.