Prostate cancer: metabolic response to cryosurgery as detected with 3D H-1 MR spectroscopic imaging.
OBJECTIVE
To determine, in patients with prostate cancer treated with cryosurgery, whether levels of choline and citrate measured at magnetic resonance (MR) spectroscopy can help discriminate regions of residual tumor from other prostatic tissues and necrosis.


METHODS
Combined MR imaging and three-dimensional proton spectroscopic imaging were performed in 25 patients (mean age, 69 years) with prostate cancer who underwent cryosurgery. Volume imaging and spectroscopic data were analytically corrected for the reception profile of the endorectal and pelvic phased-array coils. Spectral data were aligned with the MR imaging data and compared with serum prostate-specific antigen levels and biopsy results.


RESULTS
Histologically confirmed necrotic tissue (432 voxels) did not demonstrate any observable choline or citrate. The (choline + creatine)/ citrate values in regions of histologically confirmed benign prostatic hyperplasia (0.61 +/- 0.21 [standard deviation], 52 voxels) and cancer (2.4 +/- 1.0, 65 voxels) after cryosurgery were not statistically significantly different from those before therapy but were statistically significantly different from the ratio in necrotic tissue and from each other. The (choline + creatine)/citrate images threshold and overlaid in color on T2-weighted images yielded an estimate of the spatial extent of prostate cancer and benign prostatic hyperplasia.


CONCLUSIONS
Volume MR imaging with MR spectroscopic imaging provided a noninvasive assessment of the presence and location of residual cancer after unsuccessful therapy and helped identify successful cryosurgery in patients who still had an elevated prostate-specific antigen level.
Kurhanewicz
J
J
Department of Radiology, University of California, San Francisco 94143-0738, USA.
Vigneron
D B
DB
Hricak
H
H
Parivar
F
F
Nelson
S J
SJ
Shinohara
K
K
Carroll
P R
PR
D000368:Aged; D002794:Choline / Q000378:metabolism; D002951:Citrates / Q000378:metabolism; D019343:Citric Acid; D003401:Creatine / Q000378:metabolism; D003452:Cryosurgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018365:Neoplasm, Residual; D011446:Prospective Studies; D011467:Prostate / Q000737:chemistry* / Q000473:pathology / Q000601:surgery; D017430:Prostate-Specific Antigen / Q000097:blood; D011470:Prostatic Hyperplasia / Q000175:diagnosis / Q000378:metabolism / Q000601:surgery; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000601:surgery*
D002951:Citrates; D019343:Citric Acid; D017430:Prostate-Specific Antigen; D003401:Creatine; D002794:Choline