Usefulness of diffusion-weighted imaging in the localization of prostate cancer.
OBJECTIVE
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
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.


CONCLUSIONS
Because the addition of DWI to T2WI improves the detectability of prostate cancer, DWI may offer a promising new approach for radiation therapy planning.
Kajihara
Hiroo
H
Department of Radiology, Kumamoto Chuo Hospital, Japan.
Hayashida
Yoshiko
Y
Murakami
Ryuji
R
Katahira
Kazuhiro
K
Nishimura
Ryuichi
R
Hamada
Yasuyuki
Y
Kitani
Kousuke
K
Kitaoka
Mitsuhiko
M
Suzuki
Yasuko
Y
Kitajima
Mika
M
Hirai
Toshinori
T
Morishita
Shoji
S
Awai
Kazuo
K
Yamashita
Yasuyuki
Y
D000328:Adult; D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005189:False Positive Reactions; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D012189:Retrospective Studies; D012680:Sensitivity and Specificity