Magnetic resonance imaging and preoperative evaluation of cancer of the kidney. The results apropos of 60 cases

Sixty renal carcinomas confirmed at surgery or autopsy were studied. Capsular effraction, present in 17 cases, was well assessed in 8 cases, under staged in 8 cases and over staged in 5 cases (sensitivity 47%, specificity 88%). Renal vein involvement was present in 11 cases. In 8 of these 11 cases, a thrombus was present in the inferior vena cava. MRI detected a thrombus in the renal veins in 10/11 cases and in 7/8 cases of caval invasion. The false negative case was due to a huge right upper pole tumor laminating the inferior vena cava. The false positive case was due to an enlarged lymph node compressing the inferior vena cava. Cranial extension of the thrombus was well assessed in 6 of the 7 cases. One thrombus in the right atrium was missed. Lymph node involvement was present in 10 cases and correctly diagnosed by MRI in 7 cases. Three false negative cases were noted, because of microscopic invasion in non enlarged lymph nodes. Adjacent organ invasion, present in 2 cases, was detected in 1 case of liver invasion. Initial results of MRI seem very promising and at present, the best indications of MRI in pre-operative evaluation of a renal carcinoma are assessment of caval extension and spread to adjacent organs in patients with large tumors.