Takayuki Sakai1, Kunio Doi2, Masami Yoneyama3, Atsuya Watanabe4, Tosiaki Miyati5, Noriyuki Yanagawa6. 1. Department of Radiology, Eastern Chiba Medical Center, 3-6-2 Okayamadai, Togane, Chiba 2838686, Japan; Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 9200942, Japan. Electronic address: sakai@tkmedical.jp. 2. The University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA; Gunma Prefectural College of Health Sciences, 323-1 Kamioki-machi, Maebashi, Gunma 3710052, Japan. 3. Philips Japan, 2-13-37 Konan, Minato-ku, Tokyo 1088507, Japan. 4. Department of General Medical Services, Chiba University, Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 2600856, Japan; Department of Orthopedic Surgery, Eastern Chiba Medical Center, 3-6-2 Okayamadai, Togane, Chiba 2838686, Japan. 5. Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 9200942, Japan. 6. Department of Radiology, Eastern Chiba Medical Center, 3-6-2 Okayamadai, Togane, Chiba 2838686, Japan.
Abstract
PURPOSE: Diffusion tensor imaging (DTI) based on a single-shot echo planer imaging (EPI-DTI) is an established method that has been used for evaluation of lumbar nerve disorders in previous studies, but EPI-DTI has problems such as a long acquisition time, due to a lot of axial slices, and geometric distortion. To solve these problems, we attempted to apply DTI based on a single-shot turbo spin echo (TSE-DTI) with direct coronal acquisition. Our purpose in this study was to investigate whether TSE-DTI may be more useful for evaluation of lumbar nerve disorders than EPI-DTI. MATERIALS AND METHODS: First, lumbar nerve roots of five healthy volunteers were evaluated for optimization of imaging parameters with TSE-DTI including b-values and the number of motion proving gradient (MPG) directions. Subsequently, optimized TSE-DTI was quantitatively compared with conventional EPI-DTI by using fractional anisotropy (FA) values and visual scores in subjective visual evaluation of tractography. Lumbar nerve roots of six patients, who had unilateral neurologic symptoms in one leg, were evaluated by the optimized TSE-DTI. RESULTS: TSE-DTI with b-value of 400 s/mm2 and 32 diffusion-directions could reduce the image distortion compared with EPI-DTI, and showed that the average FA values on the symptomatic side for six patients were significantly lower than those on the non-symptomatic side (P < 0.05). CONCLUSION: Tractography with TSE-DTI might show damaged areas of lumbar nerve roots without severe image distortion. TSE-DTI might improve the reproducibility in measurements of FA values for quantification of a nerve disorder, and would become a useful tool for diagnosis of low back pain.
PURPOSE: Diffusion tensor imaging (DTI) based on a single-shot echo planer imaging (EPI-DTI) is an established method that has been used for evaluation of lumbar nerve disorders in previous studies, but EPI-DTI has problems such as a long acquisition time, due to a lot of axial slices, and geometric distortion. To solve these problems, we attempted to apply DTI based on a single-shot turbo spin echo (TSE-DTI) with direct coronal acquisition. Our purpose in this study was to investigate whether TSE-DTI may be more useful for evaluation of lumbar nerve disorders than EPI-DTI. MATERIALS AND METHODS: First, lumbar nerve roots of five healthy volunteers were evaluated for optimization of imaging parameters with TSE-DTI including b-values and the number of motion proving gradient (MPG) directions. Subsequently, optimized TSE-DTI was quantitatively compared with conventional EPI-DTI by using fractional anisotropy (FA) values and visual scores in subjective visual evaluation of tractography. Lumbar nerve roots of six patients, who had unilateral neurologic symptoms in one leg, were evaluated by the optimized TSE-DTI. RESULTS:TSE-DTI with b-value of 400 s/mm2 and 32 diffusion-directions could reduce the image distortion compared with EPI-DTI, and showed that the average FA values on the symptomatic side for six patients were significantly lower than those on the non-symptomatic side (P < 0.05). CONCLUSION: Tractography with TSE-DTI might show damaged areas of lumbar nerve roots without severe image distortion. TSE-DTI might improve the reproducibility in measurements of FA values for quantification of a nerve disorder, and would become a useful tool for diagnosis of low back pain.