小肾癌在64层螺旋CT多期增强扫描中的影像特征

Imaging features of small renal cell carcinomas during multiphasic 64-slice spiral CT scans

目的研究小肾癌在64层螺旋CT多期动态扫描中的影像特征。方法 20例经手术病理证实的小肾癌患者,包括透明细胞癌18例,嫌色细胞癌及乳头状细胞癌各1例,术前均经增强前与增强后皮质期、实质期以及排泄期扫描,全部操作是采用GELight-speed 64层螺旋CT机进行的。对所有患者的CT表现进行了回顾性分析。结果 20例小肾癌患者均为单发,左侧9例,右侧11例,肿瘤平均直径2.3±0.4 cm(范围1.6～2.9 cm)。局限于肾内4例,突出于肾轮廓外16例,但无1例伴发肾周、肾静脉或下腔静脉受侵及淋巴结转移。CT平扫检出16例,其中13例的瘤体呈低密度,增强后皮质期及实质期20例全部检出,其中18例的瘤体明显强化。皮质期瘤体CT值低于或达到对侧正常肾皮质,实质期瘤体CT值下降,排泄期瘤体CT值进一步下降,呈低密度影,表现为"快进快出"的强化形式。结论 64层螺旋CT多期扫描能直观、立体地显示小肾癌的部位、大小及其与周围结构的关系,尤其是它的时相特征对于术前确诊和制定手术方案至关重要。

Objective To investigate the imaging features of small renal cell carcinomas（SRCC） during multiphasic 64-slice spiral CT scans.Methods Twenty patients with surgically and pathologically proved SRCC which comprised 18 clear cell RCC,1 chromophobe RCC and 1 papillary RCC underwent precontrast and postcontrast cortical phase,parenchymal phase and excretory phase scans before the operation.All procedures were performed by using a GE Light-speed 64-slice spiral CT scanner.CT findings of all patients were analyzed retrospectively.Results The study demonstrated that there were 20 single SRCCs in 20 patients,which comprised 9 in the left kidney and 11 in the right one.The diameter of SRCCs ranged from 1.6 cm to 2.9 cm,mean diameter,2.3±0.4 cm.SRCCs localized in the renal contour and expanded out the renal contour were found in 4 and 16 cases,respectively,but no those associated with infiltrating of renal periphery,renal vein or inferior vena cava and lymph node metastasis were found in any case.Plain CT scans detected the masses of 16 cases in whom those of 13 cases appeared as hypodensity.Postcontrast cortical phase and parenchymal phase scans detected the masses of all 20 patients in whom those of 18 cases appeared as obvious enhancement.The CT value of SRCCs in cortical phase was lower than or equal to that of contralateral normal kidney cortex.The CT value of SRCCs in parenchymal phase was decreased and then farther decreased in excretory phase and appeared as hypodense shadows with enhanced pattern of ＂quick entrance-quick discharge＂.Conclusion Multiphasic 64-slice spiral CT scanning could stereoscopically and directly show the site and size of SRCCs and their relationship with peripheral structures,especially the enhanced patterns or phasic characteristics of SRCCs in multiphasic CT scans are particularly important for the preoperative definite diagnosis and planning of a partial nephrectomy.