Tom W.J. Scheenen, Presenter: Research collaboration, Siemens AG, Erlangen, Germany

Elisabeth Weiland, Abstract Co-Author: Employee, Siemens AG, Erlangen, Germany

Paul Van Hecke, Abstract Co-Author: Nothing to Disclose

Marc Paul Lemort MD, Abstract Co-Author: Nothing to Disclose

Peter Bachert, Abstract Co-Author: Nothing to Disclose

Heinz-Peter Wilhelm Schlemmer MD, PhD, Abstract Co-Author: Nothing to Disclose

Dale Robert Broome MD, Abstract Co-Author: Nothing to Disclose

Geert M. Villeirs MD, PhD, Abstract Co-Author: Nothing to Disclose

Jian-ping Lu PhD, Abstract Co-Author: Nothing to Disclose

Jurgen J. Futterer MD, Abstract Co-Author: Nothing to Disclose

Jelle O. Barentsz MD, PhD, Abstract Co-Author: Nothing to Disclose

Stefan Roell PhD, Abstract Co-Author: Employee, Siemens AG, Erlangen, Germany

Arend Heerschap PhD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

The IMAPS trial was set up to investigate the value of 1H-Magnetic Resonance Spectroscopic Imaging (1H-MRSI) at 1.5 Tesla in localizing prostate carcinoma in both the peripheral zone and the central gland of the prostate of patients with prostate cancer

99 patients with proven prostate cancer and 10 age-matched volunteers (from 8 institutions) were measured with 3D spectroscopic imaging (Magn Reson Med 2004;52:80-88) on 1.5T Siemens Magnetom scanners. Two radiologists independently classified voxels to 4 different tissues in the prostate, blinded to the spectra, on the basis of the histopathological analyses of 99 resected prostates and the MRSI matrices overlaid on T2-weighted images. Spectra from these voxels were automatically fitted and the (Choline+Creatine)/Citrate ratios (CC/C) were calculated as a marker for cancer tissue. Cancer voxels were additionally classified according to tumor size and matching certainty.

Overall 400/569 benign, and 204/226 assigned cancer voxels contained spectra of sufficient quality for a correct automated fit. Mean CC/C values (± SD) in patients were: 0.31 ± 0.13 for benign peripheral zone, 0.38 ± 0.15 for benign central gland, and 0.44 ± 0.21 for benign (peri-)urethral area. Cancer tissue was characterized by a mean CC/C of 0.91 (median 0.68). Cancer CC/C increased with tumor size and matching certainty. No significant differences in CC/C values of benign tissues were found between different participating institutions. In an ROC analysis of the discrimination between cancer and benign tissue with all correctly fitted benign voxels and cancer voxels classified as probably or definitely inside cancer tissue as the unit of analysis, the area under the curve was 0.88 for the peripheral zone and 0.76 for the combined central gland and urethra.

1H-MRSI of the prostate provides consistent data across different institutions, with the ability of separating cancer from benign tissue in both the central gland and the peripheral zone of the prostate.

Validation of in vivo 1H-MRSI of the prostate in discriminating cancer from benign tissue across patients from multiple institutions.

Scheenen, T, Weiland, E, Van Hecke, P, Lemort, M, Bachert, P, Schlemmer, H, Broome, D, Villeirs, G, Lu, J, Futterer, J, Barentsz, J, Roell, S, Heerschap, A, et al, , Final Results of IMAPS: An International Multi-Centre Assessment of Prostate MR Spectroscopy.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6016154.html