2014 年 26 巻 3 号 p. 229-236
Endometrial cancer is the seventh most common human malignancy and the most common form of cancer treated in women by obstetrics and gynecology departments. Until now, magnetic resonance imaging (MRI) has been used for pre-surgical evaluation of endometrial cancer and evaluating the depth of myometrial invasion, in addition to being a valuable diagnostic tool. Diffusion-weighted imaging (DWI) has been reported as useful in distinguishing between benign and malignant tumors when observing lesions in the endometrium. Subsequent reports suggest that DWI is also effective in identifying malignancy and diagnosing local extension in a range of tissues. Based on this, we implemented a study of the effectiveness of DWI in identifying local extension of endometrial cancer. This study enrolled patients undergoing surgery at this hospital for cancer of the uterine body during the six years from January 2008 to February 2014. Cases in which images were unclear or the lesions were too small to be described by MRI examination were excluded, leaving 61 patients in the study. Using the results from pre-surgical MRI, a sequence comprising a T2-weighted axial view alone and a T2-weighted axial view to which a diffusion-weighted axial view had been added was created for each patient. Two radiologists then independently examined the image sequence to determine localized extension. Following surgery, the pre-surgical assessment was compared to the localized extension determined by histopathology of post-surgical samples to evaluate the effectiveness of adding diffusion-weighted imaging to the process. The first radiographic interpreter's rate of correct diagnosis using the T2-weighted axial view alone was 45 out of 55 cases (81.8%), while using the T2-weighted axial view to which a diffusion-weighted axial view had been added gave a correct diagnosis rate of 51 out of 55 cases (92.7%). The second radiographic interpreter's rate of correct diagnosis using the T2-weighted axial view alone was 41 out of 55 cases (74.5%), while using the T2-weighted axial view with diffusion-weighted axial view added gave a correct diagnosis rate of 51 out of 55 cases (92.7%). These differences were statistically significant based on the McNemar testing. This study confirmed that DWI is an effective means of diagnosing localized extension from images. It is anticipated that DWI will be used in the future clinical workplace to provide more accurate pre-surgical diagnoses.
