螺旋CT双期扫描对不同肾癌亚型的诊断价值

目的 探讨各肾癌亚型在螺旋CT增强双期扫描中的表现特点,提高术前诊断准确率.方法 回顾性分析中国医学科学院肿瘤医院2001年1月至2008年12月间经手术病理证实的肾癌患者术前螺旋CT双期扫描图像460例.分别观察各肾癌亚型的瘤体大小、形态、边界、内部结构及强化特点等指标.结果 肿瘤强化程度、强化模式、动-静脉期的强化落差、伴有变性、坏死及密度变化在透明细胞癌与嫌色细胞癌和乳头状癌之间差异有统计学意义(P<0.05).透明细胞癌为高血供肿瘤,强化明显(80.9%),在皮髓质与实质期间的落差大,≥30 HU者占57.9%,以其为标准的敏感性及特异性为57.9%,91.9%.强化模式以周边环状及不均匀强化居多(66.3%,94.6%);密度不均匀(91.6%)及常伴有变性坏死(60.5%).嫌色细胞癌为中等血供肿瘤,中等强化(77.1%),落差小(<30 HU者占80.0%),以落差位于0～30 HU为诊断标准时,其敏感性、特异性为80.0%、66.1%,强化模式以均匀强化居多(60.0%),密度均匀(65.7%)为其突出特点.乳头状癌为低血供肿瘤,轻度或无强化占70.4%,落差小(<30 HU者占92.6%)其中63.0%延迟强化(CT值升高)为其特点,以落差<0 HU为诊断标准时,其敏感性、特异性为63.0%、91.8%,强化模式以均匀强化为多(48.1%),密度均匀(63.0%).未分类癌常以周边环状(9/12例)、明显(7/12例)强化、密度不均匀伴有变性坏死(9/12)为特点.多房囊性肾癌表现为多房囊肿样,增强后囊壁有强化可能是其诊断要点.结论 螺旋CT双期扫描对不同肾癌亚型的术前诊断中有重要作用,依据肾癌各亚型CT扫描特点的不同,术前大多能够做出正确诊断.

Differentiation of subtypes of renal cell carcinoma by double-phase helical computed tomography

Objective To evaluate the imaging features of different subtypes of renal cell carcinoma (RCC) by double-phase helical computed tomography (CT) and to enhance its pre-operative diagnosis level.Methods A total of 460 RCC were reviewed retrospectively.Tumor size,enhancement degree,enhancement drop between corticomedullary (CMP),nephrographic (NP),enhancement pattern,and tumor density (homogeneity,degeneration or necrosis,calcification) were observed respectively.The clear cell,chromophobe and papillary types were analyzed for statistical analysis.Results They had difference in enhancement pattern and tumor density of clear cell,chromophobe ( P<0.05 ) and papillary types ( P <0.05).There were differences in enhancement degree,enhancement drop and combine degeneration or necrosis in all subtypes of RCC ( P<0.05 ).The clear cell type was of hypervascular tumor and showed a stronger enhancement (80.9%) than other types.The enhancement drop was also higher than other types and 57.9% of it was ≥30 HU.As for ≥30 HU,the clear cell type was diagnosed with a 57.9% sensitivity and a 91.9% specificity.Clear cell type tended to appear as peripheral and heterogeneous enhancement (66.3%,94.6% );it was likely heterogeneous in density (91.6%) with frequent degeneration or necrosis (60.5%).The chromophobe type was of moderate vascular tumor and it exhibited middle-level enhancement (77.1%).The enhancement drop was low ( <30 HU,80.0%).As for 0-30 HU,the chromophobe type was diagnosed with an 80.0% sensitivity and a 66.1% specificity.Its pattern ended to appear as homogeneous enhancement (65.7%);Homogeneous density,degeneration and necrosis were characteristic signs of chromophobe type.The papillary type was of hypovascular tumor and it exhibited slight or no enhancement (70.4%).The enhancement drop was low ( <30 HU,92.6% ) and the gradual enhancement (63.0%) was characteristic of this type.As for 0 Hu,the papillary type was diagnosed with a 63.0% sensitivity and a 91.8% specificity.It tended to appear as homogeneous density (63.0% ).The unclassified type tended to appear as peripheral (9/12 cases) and stronger enhancement (7/12 cases) and heterogeneous density with degeneration or necrosis (9/12 cases).The multilocular cystic RCC appeared as complex cyst.And cystic wall enhancement was an important diagnostic point of cystic RCC.Conclusion Doublephase helical CT plays an important role in the pre-operative differentiation of subtypes of RCC.Each type of RCC has its own features.A clinician may reach a correct pre-operative diagnosis.