Abstract: Objective To assess the role of 3T enhancement magnetic resonance imaging (MRI) in the prospective characterization of intratesticular tumors and pseudotumors. Methods A perspective study of 67 patients suspected of testicular disease was conducted. All patients were performed by using the 3.0T magnet.There were 65 consecutive patients with histologically confirmed, 2 patients with clinical follow-up. Via the histological characterization of testicular neoplasm as the reference standard, the diagnostic performance of MRI was compared. MR imaging allows localization of the mass (intratesticular or extratesticular)and further characterization of the lesion (solid or cystic, fat, hemorrhage, fibrosis). Gadolinium-enhanced MR imaging characteristics of tumors and pseudotumors(heterogeneous enhancement, fibrovascular septa enhancement, or no enhancement).Tumor local staging classification(invade into the tunica albuginea, epididymis, spermatic cord or scrotal wall). Results Totally 64 patients with 67 testicular lesions, 35(52.2%)of which were malignant and 32(47.8%)benign. The coherence between MRI and histologic diagnosis in differentiating benign from malignant intratesticular lesions was very well, Kappa=0.88,P value<0.001. The pathological diagnosis as the gold standard, the sensitivity of MRI in differentiating benign from malignant intratesticular lesions was 94.3%,specificity 93.8%, positive predictive value 94.3%, misdiagnosis rate 6.2%,rate of missed diagnosis 5.7%, MRI findings led to a correct histological diagnosis in 60(89.6%) of 67cases. Conclusion MRI is highly accurate in histologic characterization of testicular tumors and pseudotumors.

Key words: testis, magnetic resonance imaging, intratesticular neoplasm, diagnosis