A comparison of T1 measurements at 1.7 and 3.4 MHz in the diagnosis of prostatic carcinoma.

To compare the specificity of T1 measurement for the diagnosis of prostatic carcinoma in vivo, two groups of patients with clinically enlarged prostate glands have been imaged. One group comprising 25 patients was imaged at 1.7 MHz the other comprising 51 patients at 3.4 MHz. T1 measurements together with the gross anatomical appearances of the prostate gland were observed and compared with the clinical and histologic diagnoses. At 1.7 MHz it was found that the T1 measurement of carcinoma of the prostate and benign hypertrophy of the prostate fell into two distinct ranges with no overlap between the two conditions. Three false-positive diagnoses of carcinoma were made in patients with prostatitis where the T1 values fell in the upper part of the carcinoma range. T1 measurement in the group studied at 3.4 MHz demonstrated no specific value for either condition and diagnosis of malignancy had to be made from the morphologic appearances of the gland. Morphologically benign hypertrophy appeared homogeneous while carcinoma appeared heterogeneous with small areas of increased T1 in the malignant part of the gland.