T1 hyperintensity of bladder urine at prostate MRI: frequency and comparison with urinalysis findings

The purpose of this study was to assess the possible clinical significance of bladder urine T1 hyperintensity based upon comparison with urinalysis findings, using a cohort of patients who underwent prostate MRI and urinalysis at a similar point in time during preoperative work-up.

We identified 56 patients who underwent prostatectomy at our institution who obtained prostate MRI and urinalysis within 1 day of each other preoperatively. A control group of 160 consecutive adult men who underwent pelvic MRI during the same time period for other indications was also identified. Two radiologists independently and in consensus reviewed the T1-weighted images to assess the frequency of bladder urine T1 hyperintensity in both groups. The urinalyses in the 56 men undergoing prostatectomy were reviewed, with the results compared between patients with and without bladder urine T1 hyperintensity.

Four (7.1%) of 56 men with prostate cancer exhibited T1 hyperintense bladder urine, compared with six (3.8%) of 160 patients exhibiting this finding in the control group (P=.288). Of the four prostate cancer patients with this finding, all exhibited a normal urinalysis. An abnormal urinalysis was identified for four of the prostate cancer patients, all of whom exhibited normal urine T1 signal intensity.

Bladder urine T1 hyperintensity may be seen occasionally in patients with prostate cancer but is not associated with abnormal urinalysis and therefore should not be regarded as a sign of acute urinary pathology.