[Comparison of various imaging in the diagnosis of renal cell carcinoma with inferior vena cava tumor thrombus combined with bland thrombus].

OBJECTIVE: To analyse the clinical and imaging data of patients with renal cell carcinoma (RCC) with inferior vena cava tumor thrombus (IVCTT), and to assess the diagnostic efficacy of ultrasound, enhanced computed tomography (CT) and enhanced magnetic resonance imaging (MRI) in the diagnosis of RCC with IVCTT combined with bland thrombus was assessed. METHODS: We retrospectively analyzed the clinical and imaging data of 56 RCC patients with IVCTT who underwent radical nephrectomy and IVC thrombectomy between January 2014 and July 2018 in Department of Urology, Peking University Third Hospital. All the patients underwent US, enhanced CT and enhanced MRI preoperatively, and all the cases were confirmed with RCC with IVCTT by histological evaluation. RESULTS: The criteria of RCC with IVCTT combined with bland thrombus was confirmed by intraoperative observation and postoperative pathology. The 56 patients were divided into bland thrombus group (n=18) and non bland thrombus group (n=38). Compared the two groups, it was found that the length of IVCTT was longer [(10.50 ± 5.55) cm vs.(6.66 ± 3.73) cm, P=0.014]; the ratio of diameter of IVCTT to maximum coronal diameter of IVC was closer to 1 [1.0 (0.7, 1.0) vs. 0.9 (0.2, 1.0), P=0.004]; the proportion of lower limb edema was higher [66.7(12/8)% vs.5.3%(2/36), P=0.005]；the proportion of segmental resection or interrupt of IVC was higher [66.7%(12/18) vs.15.8%(6/38), P<0.001], with statistical significance. Compared with the three imaging methods of US, enhanced CT and MRI, the highest sensitivity was MRI (77.8%), the highest specificity was enhanced MRI and enhanced CT (97.4%), the highest accuracy was enhanced CT and enhanced MRI (83.9%), the highest positive predictive value was enhanced CT (90.9%) and the highest negative predictive value was enhanced MRI (89.2%). CONCLUSION: For the patients that RCC with IVCTT combined with bland thrombus, the length of IVCTT is longer, and the ratio of the diameter of IVCTT to the maximum corona diameter of IVC is closer to 1, and more likely to cause lower limb edema. Preoperative comprehensive evaluation of multiple images is needed to improve the accuracy of diagnosis.