Prostatic MR imaging. Accuracy in differentiating cancer from other prostatic disorders.
OBJECTIVE
We assessed the accuracy of MR imaging in differentiating between cancer and other prostatic disorders, and evaluated the diagnostic criteria for various prostatic diseases.


METHODS
A total of 74 endorectal coil MR studies were performed on 72 patients. Twenty patients had prostatic cancer, 20 benign prostatic hyperplasia (BPH), 4 acute bacterial prostatitis, 5 chronic bacterial prostatitis (2 also belonging to the previous category), 19 chronic non-bacterial prostatitis/chronic pelvic pain syndrome, and 6 were symptomless voluntary controls. All studies were interpreted by two experienced radiologists in random order. Radiologists were blinded to all clinical data including the age of the patients. Based on MR findings, both radiologists filled in a form covering diagnostic criteria and diagnosis.


RESULTS
Accuracy in diagnosing prostate cancer was 74%. Sensitivity was 50% and specificity 83%, and positive and negative predictive values were 53 and 82%, respectively. Bacterial prostatitis showed some features similar to carcinoma. Abundant BPH rendered cancer detection more difficult. No diagnostic criterion was clearly better than the others. Interobserver agreement on the MR diagnosis ranged from moderate to good.


CONCLUSIONS
Without knowledge of accurate clinical data, MR seems to be too insensitive in detecting prostate cancer to be used as a primary diagnostic tool.
Ikonen
S
S
Department of Radiology, Helsinki University Central Hospital, and The Finnish Institute of Occupational Health, Helsinki, Finland.
Kivisaari
L
L
Tervahartiala
P
P
Vehmas
T
T
Taari
K
K
Rannikko
S
S
D000368:Aged; D001424:Bacterial Infections / Q000175:diagnosis; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011469:Prostatic Diseases / Q000175:diagnosis; D011470:Prostatic Hyperplasia / Q000175:diagnosis; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D011472:Prostatitis / Q000175:diagnosis; D012680:Sensitivity and Specificity