Clinical and in vitro magnetic resonance imaging of prostatic carcinoma.

Magnetic resonance imaging (MRI) of the prostate was accomplished in 10 patients who subsequently had surgical exploration for histologic confirmation and tumor staging. Eight patients were found to have carcinoma of the prostate. Two patients had malignancies of the urinary bladder and were treated with radical resection of the bladder and prostate. The prostatic glands in the latter two patients were free of tumor. One gland was entirely normal; the other had extensive acute and chronic prostatitis. Two resected prostates with carcinoma and one normal prostate were available for in vitro MRI in a clinical magnetic resonance unit. The MRI finding of prostatic carcinoma was heterogeneous signal patterns, seen best on T2-weighted studies. A similar pattern was identified in the gland with acute and chronic prostatitis. There was a homogeneous MRI signal pattern of the normal prostate gland examined in vitro. In two instances, the MRI studies were accurate for the identification of tumor spread to the seminal vesicles, not diagnosed at the time of surgical resection. Microscopic metastatic disease of the lymph nodes in four patients was not identified by MRI.