Prostate cancer: sextant localization with MR imaging, MR spectroscopy, and 11C-choline PET/CT.
OBJECTIVE
To retrospectively compare sensitivity and specificity of magnetic resonance (MR) imaging, three-dimensional (3D) MR spectroscopy, combined MR imaging and 3D MR spectroscopy, and carbon 11 (11C)-choline positron emission tomography (PET)/computed tomography (CT) for intraprostatic tumor sextant localization, with histologic findings as reference standard.


METHODS
The local ethics committee on human research provided approval and a waiver of informed consent for the retrospective study. MR imaging, 3D MR spectroscopy, and 11C-choline PET/CT results were retrospectively reviewed in 26 men with biopsy-proved prostate cancer (mean age, 64 years; range, 51-75 years) who underwent radical prostatectomy. Cancer was identified as areas of nodular low signal intensity on T2-weighted MR images. At 3D MR spectroscopy, choline-plus-creatine-to-citrate and choline-to-creatine ratios were used to distinguish healthy from malignant voxels. At PET/CT, focal uptake was visually assessed, and maximum standardized uptake values (SUVs) were recorded. Agreement between 3D MR spectroscopic and PET/CT results was calculated, and ability of maximum SUV to help localize cancer was assessed with receiver operating characteristic analysis. Significant differences between positive and negative sextants with respect to mean maximum SUV were calculated with a paired t test.


RESULTS
Sensitivity, specificity, and accuracy were, respectively, 55%, 86%, and 67% at PET/CT; 54%, 75%, and 61% at MR imaging; and 81%, 67%, and 76% at 3D MR spectroscopy. The highest sensitivity was obtained when either 3D MR spectroscopic or MR imaging results were positive (88%) at the expense of specificity (53%), while the highest specificity was obtained when results with both techniques were positive (90%) at the expense of sensitivity (48%). Concordance between 3D MR spectroscopic and PET/CT findings was slight (kappa=0.139).


CONCLUSIONS
In localizing cancer within the prostate, comparable specificity was obtained with either 3D MR spectroscopy and MR imaging or PET/CT; however, PET/CT had lower sensitivity relative to 3D MR spectroscopy alone or combined with MR imaging.
Testa
Claudia
C
Department of Clinical Medicine and Applied Biotechnology D. Campanacci, Diagnostic Imaging Section V. Bollini, Pathologic Anatomy Unit, Institute of Oncology F. Addarii, P.E.T. Center, Policlinico S. Orsola-Malpighi, University of Bologna, Italy.
Schiavina
Riccardo
R
Lodi
Raffaele
R
Salizzoni
Eugenio
E
Corti
Barbara
B
Farsad
Mohsen
M
Kurhanewicz
John
J
Manferrari
Fabio
F
Brunocilla
Eugenio
E
Tonon
Caterina
C
Monetti
Nino
N
Castellucci
Paolo
P
Fanti
Stefano
S
Coe
Manuela
M
Grigioni
Walter F
WF
Martorana
Giuseppe
G
Canini
Romeo
R
Barbiroli
Bruno
B
D000328:Adult; D000368:Aged; D001706:Biopsy; D002250:Carbon Radioisotopes; D002794:Choline; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
D002250:Carbon Radioisotopes; D002794:Choline