Prospective assessment of MRI for imaging retroperitoneal metastases from testicular germ cell tumours.

AIM: To determine the sensitivity of magnetic resonance imaging (MRI) in the detection of retroperitoneal lymph nodes in patients with testicular germ cell tumours (TGCT).

METHODS AND MATERIALS: A prospective study of 52 patients (mean age 34 years, range 18-54 years) was performed. Imaging of the retroperitoneum was performed using multidetector computed tomography (CT) and 1.5 T MRI systems. The CT and MRI images were read independently by three observers. The number, size, and site of enlarged nodes (> or =10 mm maximum short axis diameter) were recorded. Retroperitoneal nodal detection on MRI was compared to CT.

RESULTS: Twenty-two (42%) of the 52 patients had no retroperitoneal disease; in remaining 30 patients 51 enlarged nodes were identified. On a per patient basis readers 1, 2, and 3 identified nodal disease in 28 of 29, 29 of 30, and 24 of 30 patients, respectively, using MRI compared to CT. Thus for experienced radiologists (readers 1 and 2) MRI is comparable to CT for nodal detection (i.e., this study excludes MRI being inferior to CT with 80% power and 5% type 1 error).

CONCLUSION: MRI offers an alternative method for staging the retroperitoneum in young patients being followed for TGCT and has the major advantage of avoiding exposure to ionizing radiation.