(Radiology Review) Combined T2-weighted MRI and diffusion-weighted imaging (DWI) is significantly better than T2-weighted imaging alone for detecting peripheral zone prostate cancer, according to a report in the August issue of American Journal of Roentgenology.
In this prospective study by Dr. Masoom Haider and colleagues at the University of Toronto in Ontario, 49 patients underwent T2-weighted MRI and DWI using a 1.5-tesla endorectal coil, prior to radical prostatectomy.
T2-weighted images alone as well as the T2-weighted images with apparent diffusion coefficient (ADC) maps were assessed for prostate cancer, and these findings were compared with whole-mount histology results, they stated.
Although DWI is more typically used in neuroradiology, recent research has shown that the ADCs calculated from DWI parametric maps are lower for prostate cancer compared with normal peripheral zone of the prostate.
"Only tumors with an area of more than 0.13 cm² (> 4 mm diameter) and a Gleason score of ≥ 6 were considered significant. The area under the receiver operating characteristic curve was used to assess accuracy," they wrote (AJR, August 2007, Vol. 189:2, pp. 323-328).
The authors reported that both T2-weighted imaging plus DWI and T2-weighted imaging alone were poorer at detecting cancer in the transitional zone, compared with detection in the peripheral zone. "For the whole prostate, sensitivity was significantly higher with T2 plus DWI (81%) than with T2 imaging alone (54%)," they wrote. For the whole prostate, T2 MRI alone was slightly more specific (91%) compared with T2 plus DWI (84%).
"Combined T2 and DWI MRI is better than T2 imaging alone in the detection of significant cancer (Gleason score ≥ 6 and diameter > 4 mm) within the peripheral zone of the prostate," they concluded.
"Combined T2-Weighted and Diffusion-Weighted MRI for Localization of Prostate Cancer"
Masoom A. Haider et al
Joint Department of Medical Imaging, Princess Margaret Hospital, University Health Network and Mount Sinai Hospital, University of Toronto, 610 University Ave., Toronto, ON M5G 2M9, Canada
AJR 2007 (August); 189:323-328
By Radiology Review
September 21, 2007
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