Localized prostate cancer: Effect of hormone deprivation therapy measured by using combined three-dimensional H-1 MR spectroscopy and MR imaging: Clinicopathologic case-controlled study

PURPOSE: To determine the accuracy of combined magnetic resonance (MR) imag ing and three-dimensional (3D) proton MR spectroscopic imaging in localizin g prostate cancer to a sextant of the gland in patients receiving hormone d eprivation therapy. MATERIALS AND METHODS: Combined MR imaging/3D MR spectroscopic imaging exam inations were performed in 16 hormone-treated patients and 48 nontreated ma tched control patients before radical prostatectomy and step-section histop athologic analysis. At MR imaging, cancer presence within the peripheral zo ne was assessed on a per sextant basis by two readers. At 3D MR spectroscop ic imaging, cancer was identified by using (choline plus creatine)-to-citra te ratios at cutoff values of 2 and 3 SDs above mean normal peripheral zone values. Data were compared by using receiver operating characteristic anal ysis. RESULTS: There was no significant difference in the ability of combined MR imaging/3D MR spectroscopic imaging to localize prostate cancer in treated versus control patients. For MR imaging alone, the sensitivity and specific ity were 91% and 48% (reader 1) and 75% and 60% (reader 2) in treated patie nts versus 79% and 60% (reader 1) and 84% and 43% (reader 2) in control pat ients. For 3D MR spectroscopic imaging alone (>3 SDs cutoff), higher specif icity (treated, 80%; controls, 73%) but lower sensitivity (treated, 56%; co ntrols, 53%) was attained. In treated patients, high sensitivity or specifi city (up to 92%) was achieved when either or both modalities indicated canc er. CONCLUSION: When performed within 4 months after initiating hormone depriva tion therapy, combined MR imaging/3D MR spectroscopic imaging had the same accuracy in localizing prostate cancer as in nontreated patients.