PELVIC ADENOPATHY IN PROSTATIC AND URINARY-BLADDER CARCINOMA - MR-IMAGING WITH A 3-DIMENSIONAL TI-WEIGHTED MAGNETIZATION-PREPARED RAPID GRADIENT-ECHO SEQUENCE

OBJECTIVE. The purpose of this study was to evaluate a magnetization-p repared-rapid gradient-echo (MP-RAGE) sequence as a three-dimensional (3D) T1-weighted MR imaging technique to reveal lymph node metastases from carcinoma of the bladder and the prostate. SUBJECTS AND METHODS. Using a 3D T1-weighted MP-RAGE sequence, MR images of 134 consecutive patients with prostatic carcinoma (n = 63) or urinary bladder carcinom a (n = 71) who were scheduled for radical prostatectomy or radical cys tectomy were correlated with histopathologic findings after fine-needl e aspiration biopsy (FNAB) (n = 6), open or laparoscopic pelvic lymph node dissection (n = 127), or autopsy (n = 1). MR imaging was used 10 times to guide FNAB in nine patients. RESULTS. The sensitivity, specif icity, accuracy, and positive predictive value of the technique were 7 5%, 98%, 90%, and 94%, respectively. Thin-slice (1.2-mm) multiplanar r econstructed images correctly revealed diseased nodes in 33 patients. However, MR imaging failed to reveal microscopic metastatic deposits i n normally sized nodes in 11 patients. Two other patients had enlarged nodes without metastasis. Furthermore, FNAB guided by MR imaging reve aled metastases in six of nine patients. CONCLUSION. MR imaging with a 3D MB-RAGE sequence was accurate in revealing nodal metastases from c arcinoma of the prostate and bladder. This imaging technique can be us ed to select patients for biopsy or laparoscopic pelvic lymph node dis section.