Usefulness of Diffusion-Weighted Imaging in the Localization of Prostate Cancer
Received 28 June 2008; received in revised form 11 August 2008; accepted 13 August 2008. published online 18 November 2008.
Purpose
Advances in high-precision radiation therapy techniques for patients with prostate cancer permit selective escalation of the radiation dose delivered to the dominant intraprostatic lesion and improve the therapeutic ratio. We evaluated the value of diffusion-weighted imaging (DWI) for dominant intraprostatic lesion assessment.
Methods and Materials
The study population consisted of 23 patients with early prostate cancer. Before undergoing total prostatectomy, they were evaluated by means of magnetic resonance imaging, including DWI. T2-weighted imaging (T2WI) with and without DWI were retrospectively assessed by six independent observers. Imaging findings were compared with pathologic results from whole prostate specimens on a lesion-by-lesion basis.
Results
Pathologic study identified 43 lesions in 23 patients. On magnetic resonance imaging, the six observers correctly identified 11–22 of 43 lesions (sensitivity, 26–51%) on T2WI alone and 20–31 (sensitivity, 47–72%) on T2WI plus DWI. Positive predictive values were 42–73% on T2WI alone and 58–80% on T2WI plus DWI. For all observers, detection was higher on combined T2WI and DWI than on T2WI alone.
Conclusion
Because the addition of DWI to T2WI improves the detectability of prostate cancer, DWI may offer a promising new approach for radiation therapy planning.
∗Department of Radiology, Kumamoto Chuo Hospital, Kumamoto, Japan
†Department of Urology, Kumamoto Chuo Hospital, Kumamoto, Japan
‡Department of Pathology, Kumamoto Chuo Hospital, Kumamoto, Japan
§Department of Radiology, University of Occupational and Environmental Health, Fukuoka, Japan
‖Department of Radiation Oncology, Kumamoto University Hospital, Kumamoto, Japan
¶Department of Diagnostic Radiology, Kumamoto University Hospital, Kumamoto, Japan
#Department of Radiology, Saiseikai Kumamoto Hospital, Kumamoto, Japan
Reprint requests to: Ryuji Murakami, M.D., Department of Radiation Oncology, Kumamoto University Hospital, 1-1-1 Honjo, Kumamoto 860-8556, Japan. Tel: (81) 96-373-5262; Fax: (81) 96-362-4330
H.K., Y.H., and R.M. chaired the study and designed it in collaboration with colleagues from various subspecialties (Y.H., Urology; M.K., Pathology; T.H. and K.A., Radiology; S.M. and R.N., Radiation Oncology). Y.Y., Chair, Diagnostic Radiology, reviewed the initial manuscript drafts and suggested helpful changes. K.K., M.K., Y.S., and K.K. were principal investigators and supplied the individual clinical data.
ABSTRACT