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Radiology Research and Practice
Volume 2011, Article ID 616852, 9 pages
http://dx.doi.org/10.1155/2011/616852
Research Article

MR Imaging of Prostate Cancer: Diffusion Weighted Imaging and (3D) Hydrogen 1 (1H) MR Spectroscopy in Comparison with Histology

1Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
2Department of Urology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
3Siemens AG, 20099 Hamburg, Germany

Received 9 November 2009; Accepted 10 May 2010

Academic Editor: David Maintz

Copyright © 2011 J. Yamamura et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose. To evaluate retrospectively the impact of diffusion weighted imaging (DWI) and (3D) hydrogen 1 (1H) MR-spectroscopy (MRS) on the detection of prostatic cancer in comparison to histological examinations. Materials and Methods: 50 patients with suspicion of prostate cancer underwent a MRI examination at a 1.5T scanner. The prostate was divided into sextants. Regions of interest were placed in each sextant to evaluate the apparent diffusion coefficient (ADC)-values. The results of the DWI as well as MRS were compared retrospectively with the findings of the histological examination. Sensitivity and specificity of ADC and metabolic ratio (MET)—both separately and in combination—for identification of tumor tissue was computed for variable discrimination thresholds to evaluate its receiver operator characteristic (ROC). An association between ADC, MET and Gleason score was tested by the non-parametric Spearman 𝜌 -test. Results. The average ADC-value was 1 . 6 5 ± 0 . 3 2 mm2/s × 10-3 in normal tissue and 0.96±0.24 mm2/s × 10-3 in tumor tissue (mean ± 1 SD). MET was 0 . 4 1 8 ± 0 . 4 3 1 in normal tissue and 2 . 0 1 0 ± 1 . 6 4 9 in tumor tissue. The area under the ROC curve was 0.966 (95%-confidence interval 0.941–0.991) and 0.943 (0.918–0.968) for DWI and MRS, respectively. There was a highly significant negative correlation between ADC-value and the Gleason score in the tumor-positive tissue probes ( 𝑛 = 6 2 , 𝜌 = 0 . 4 0 5 , 𝑃 = . 0 0 1 ). MRS did not show a significant correlation with the Gleason score ( 𝜌 = 0 . 1 1 7 , 𝑃 = . 3 6 6 ). By using both the DWI and MRS, the regression model provided sensitivity and specificity for detection of tumor of 91.9% and 98.3%, respectively. Conclusion. The results of our study showed that both DWI and MRS should be considered as an additional and complementary tool to the T2-weighted MRI for detecting prostate cancer.