Efficacy of preoperative cine magnetic resonance imaging in evaluation of adhesion of renal cancer thrombus to inferior vena cava wall.

ABSTRACT

OBJECTIVE: In renal cell carcinoma with inferior vena cava (IVC) thrombus, adhesion to, or invasion into, the IVC wall will often increase the level of surgical difficulty and even necessitate resection of the IVC. It will generally be difficult to perform an accurate preoperative assessment using the standard imaging modalities of contrast-enhanced computed tomography and standard magnetic resonance imaging (MRI). Cine MRI is an MRI sequence that captures motion to produce detailed information on both the anatomy and the dynamic motion. In the present study, we evaluated the accuracy of preoperative cine MRI for determining the need for IVC wall resection, with validation of the imaging findings according to the intraoperative findings. METHODS: A total of 15 patients who had undergone radical nephrectomy and tumor thrombectomy from May 2018 to April 2020 met the inclusion criteria. The primary outcome of interest was the need for IVC resection because of adhesion or invasion of a venous tumor thrombus. Cine MRI was used to evaluate the blood flow between the tumor thrombus and the IVC wall and the presence of tumor thrombus mobility during free respiration. The sensitivity and specificity were calculated for preoperative cine MRI for determining the need for IVC wall resection. The Fisher exact test was used to determine the association between intraoperative IVC wall resection and the cine MRI findings. Furthermore, receiver operating characteristic curves and the area under the curve were used to compare the accuracy of conventional MRI and cine MRI. RESULTS: Of the 15 patients, 8 (53.3%) had undergone IVC resection. We found that the absence of both dynamic blood flow and tumor thrombus mobility on cine MRI could reliably predict for IVC resection with 100% (95% confidence interval, 51.8%-100%) sensitivity and 85.7% (95% confidence interval, 42.1%-1.00%) specificity. The area under the receiver operating characteristic curve was 0.821 for conventional MRI and 0.929 for cine MRI. CONCLUSIONS: In the preoperative setting, cine MRI could be a helpful examination modality to predict for the need for IVC wall resection for patients with renal cell carcinoma with venous tumor thrombus.