Ichiro Yamada1, Norio Yoshino2, Keigo Hikishima3, Junichiro Sakamoto2, Misaki Yokokawa4, Yu Oikawa4, Hiroyuki Harada4, Tohru Kurabayashi2, Yukihisa Saida5, Ukihide Tateishi5, Akane Yukimori6, Toshiyuki Izumo6, Shun Asahina7. 1. Department of Diagnostic Radiology and Nuclear Medicine, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. Electronic address: yamada.crad@tmd.ac.jp. 2. Department of Oral and Maxillofacial Radiology, Tokyo Medical and Dental University, Tokyo, Japan. 3. Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan. 4. Department of Oral and Maxillofacial Surgery, Tokyo Medical and Dental University, Tokyo, Japan. 5. Department of Diagnostic Radiology and Nuclear Medicine, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. 6. Department of Oral Pathology, Tokyo Medical and Dental University, Tokyo, Japan. 7. Siemens Healthcare K.K., Tokyo, Japan.
Abstract
PURPOSE: In this study, we aimed to determine the usefulness of diffusion kurtosis imaging (DKI) as a noninvasive method for evaluation of the histologic grade and lymph node metastasis in patients with oral carcinoma. MATERIALS AND METHODS: Twenty-seven patients with oral carcinoma were examined with a 3-T MR system and 16-channel coil. DKI data were obtained by a single-shot echo-planar imaging sequence with repetition time, 10,000 ms; echo time, 94 ms; field of view, 250 × 204.25 ms; matrix, 120 × 98; section thickness, 4 mm; four b values of 0, 500, 1000, and 2000 s/mm2; and motion-probing gradients in three orthogonal directions. Diffusivity (D) and kurtosis (K) were calculated using the equation: S = S0 ∙ exp(-b ∙ D + b2 ∙ D2 ∙ K/6). Conventional apparent diffusion coefficient (ADC) was also calculated. The MR images were compared with the histopathologic findings. RESULTS: Relative to the histologic grades (Grades 1, 2, and 3) of the 27 oral carcinomas, D values showed a significant inverse correlation (r = -0.885; P < 0.001) and K values showed a significant positive correlation (r = 0.869; P < 0.001), whereas ADC values showed no significant correlation (r = -0.311; P = 0.115). When comparing between metastatic and non-metastatic lymph nodes, significant differences in the D values (P < 0.001) and K values (P < 0.001), but not the ADC values (P = 0.110) became apparent. CONCLUSIONS: In patients with oral carcinoma, DKI seems to be clinically useful for the evaluation of histologic grades and lymph node metastasis.
PURPOSE: In this study, we aimed to determine the usefulness of diffusion kurtosis imaging (DKI) as a noninvasive method for evaluation of the histologic grade and lymph node metastasis in patients with oral carcinoma. MATERIALS AND METHODS: Twenty-seven patients with oral carcinoma were examined with a 3-T MR system and 16-channel coil. DKI data were obtained by a single-shot echo-planar imaging sequence with repetition time, 10,000 ms; echo time, 94 ms; field of view, 250 × 204.25 ms; matrix, 120 × 98; section thickness, 4 mm; four b values of 0, 500, 1000, and 2000 s/mm2; and motion-probing gradients in three orthogonal directions. Diffusivity (D) and kurtosis (K) were calculated using the equation: S = S0 ∙ exp(-b ∙ D + b2 ∙ D2 ∙ K/6). Conventional apparent diffusion coefficient (ADC) was also calculated. The MR images were compared with the histopathologic findings. RESULTS: Relative to the histologic grades (Grades 1, 2, and 3) of the 27 oral carcinomas, D values showed a significant inverse correlation (r = -0.885; P < 0.001) and K values showed a significant positive correlation (r = 0.869; P < 0.001), whereas ADC values showed no significant correlation (r = -0.311; P = 0.115). When comparing between metastatic and non-metastatic lymph nodes, significant differences in the D values (P < 0.001) and K values (P < 0.001), but not the ADC values (P = 0.110) became apparent. CONCLUSIONS: In patients with oral carcinoma, DKI seems to be clinically useful for the evaluation of histologic grades and lymph node metastasis.