Kajihara Hiroo, Hayashida Yoshiko, Murakami Ryuji, Katahira Kazuhiro, Nishimura Ryuichi, Hamada Yasuyuki, Kitani Kousuke, Kitaoka Mitsuhiko, Suzuki Yasuko, Kitajima Mika, Hirai Toshinori, Morishita Shoji, Awai Kazuo, Yamashita Yasuyuki
Department of Radiology, Kumamoto Chuo Hospital, Japan.
Int J Radiat Oncol Biol Phys. 2009 Jun 1;74(2):399-403. doi: 10.1016/j.ijrobp.2008.08.017. Epub 2008 Nov 18.
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.
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.
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.
Because the addition of DWI to T2WI improves the detectability of prostate cancer, DWI may offer a promising new approach for radiation therapy planning.
前列腺癌患者高精度放射治疗技术的进步使得能够选择性地提高对前列腺主要病灶的放射剂量，并提高治疗比。我们评估了扩散加权成像（DWI）在评估前列腺主要病灶方面的价值。
研究人群包括23例早期前列腺癌患者。在进行前列腺全切术前，他们接受了包括DWI在内的磁共振成像评估。由六名独立观察者对有和没有DWI的T2加权成像（T2WI）进行回顾性评估。将影像学表现与全前列腺标本的病理结果逐病灶进行比较。
病理研究在23例患者中发现了43个病灶。在磁共振成像中，六名观察者仅在T2WI上正确识别出43个病灶中的11 - 22个（敏感性，26 - 51%），在T2WI加DWI上正确识别出20 - 31个（敏感性，47 - 72%）。单独T2WI的阳性预测值为42 - 73%，T2WI加DWI的阳性预测值为58 - 80%。对于所有观察者来说，T2WI和DWI联合检测的结果高于单独T2WI检测。
由于在T2WI上增加DWI可提高前列腺癌的可检测性，DWI可能为放射治疗计划提供一种有前景的新方法。
