Value of 3.0T magnetic resonance imaging in the diagnosis of retroperitoneal tumors

Background: To evaluate the diagnostic value of 3.0T MR for differentiating benign from malignant primary retroperitoneal tumors (RPTs). Methods: A total of 81 patients (44 males and 37 females; 31 benign and 50 malignant lesions) who underwent surgical resection for RPT were evaluated retrospectively. The MR features included lesion location, number, size, margin, surfaces, texture (solid or non-solid), MRhyperintense and MRhypointense signal intensity, apparent diffusion coefficient (ADC) value and the presence of fat, necrosis and hemorrhage. Categorical variables were tested with a chi(2) test or Fisher's exact test for the diagnostic indices and the sensitivity and specificity of MR characteristics. Results: Using six indices (ill-defined margins, irregular surface, major diameter >5.85 cm, minor diameter >5.35 cm, solid texture and ADC <1.2x10(-3) mm(2)/s) to diagnose malignant RPT, sensitivity and specificity were 36.0% vs. 93.5%, 68.0% vs. 58.1%, 80.0% vs. 64.5%, 64.0% vs. 90.3%, 65.0% vs. 63.5%, and 64.0% vs. 74.2%, respectively. Combining all those radiological features into a comprehensive evaluation, sensitivity and specificity were 82.0% and 77.4%, respectively (chi(2) =27.984, P<0.001) when scores >= 4. Other findings had no statistical significance. Conclusions: More accurate differential diagnosis of primary RPTs could be made through comprehensive analysis of combined diagnostic indices.