NEW METHOD OF EVALUATING MUSCLE FUNCTION WITH MAGNETIC RESONANCE IMAGER

• Project/Area Number: 15500365
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Rehabilitation science/Welfare engineering
• Research Institution: Kyushu University
• Principal Investigator: HATAKENAKA Masamitsu Kyushu University, University Hospital, Radiology, Assistant professor, 大学病院, 講師 (40253413)
• Co-Investigator(Kenkyū-buntansha): HONDA Hiroshi Kyushu University, Faculty of Medicine, Clinical Radiology, Professor, 大学院・医学研究院, 教授 (90145433) ; YOSHIMITSU Kengo Kyushu University, University Hospital, Radiology, Assistant professor, 大学病院, 講師 (20274467) ; YABUUCHI Hidetake Kyushu University, University Hospital, Radiology, Assistant, 大学病院, 助手 (70380623) ; 薮内 英剛 九州大学, 大学院・医学研究院, 助手 ; 高橋 直幹 九州大学, 大学病院, 医員 ; 足立 利貞 九州大学, 大学病院, 助手 (10335979) ; 前田 豊樹 九州大学, 生体防御医学研究所, 助手 (30264112)
• Project Period (FY): 2003 – 2005
• Project Status: Completed (Fiscal Year 2005)
• Budget Amount: ¥3,500,000 (Direct Cost: ¥3,500,000); Fiscal Year 2005: ¥900,000 (Direct Cost: ¥900,000); Fiscal Year 2004: ¥1,000,000 (Direct Cost: ¥1,000,000); Fiscal Year 2003: ¥1,600,000 (Direct Cost: ¥1,600,000)
• Keywords: steroid / myopathy / MR / relaxation time / diffusion / MRI / ADC

Research Abstract

Purpose :
To determine whether muscle fiber atrophy associated with steroid myopathy can be detected with T2 relaxation time.
Materials and Methods:
Animal and human studies were approved by the ethics committee. Informed consent was obtained. Twelve rabbits were divided into a group that received 3 mg/kg of triamcinolone subcutaneously each day for 10 consecutive days (n_6) and a control group that received saline (n_6). Magnetic resonance (MR) imaging was performed before and after treatment. T2 and fat deposition ratio (FDR) of soleus and gastrocnemius muscles before and after treatment and between control rabbits and rabbits treated with steroids were compared by using two-way repeated analysis of variance and Bonferroni post hoc test to evaluate effects of steroid treatment. After imaging, rabbits were sacrificed. Extracellular space ratio (ECSR) and fiber diameter were examined. Correlation among T2, ECSR, and diameter of type 2 muscle fibers was analyzed with a Pearson correlation test with Bonferroni correction in gastrocnemius to determine factors affecting T2. In humans, T2 relaxation time and FDR of both muscles were compared between volunteers not treated with steroids and patients treated with steroids by using an unpaired t test to evaluate the effects of steroids.
Results :
In rabbits, T2 of gastrocnemius muscle was significantly (P_.01) longer after steroid treatment than before steroid treatment and was also significantly (P_.01) longer than after saline administration. T2 of the gastrocnemius showed no significant difference in control rabbits before or after saline administration or in control rabbits and rabbits before steroid administration. T2 of the soleus muscle or FDR of either muscle showed no significant difference. There was a significant correlation (P_.01) among T2, ECSR, and diameter of type 2 muscle fibers in the gastrocnemius. In humans, T2 of the gastrocnemius was significantly (P_.01) longer in patients than in volunteers. T2 of the soleus or FDR of eithermuscle showed no significant difference.
Conclusion :
Muscle fiber atrophy associated with steroid myopathy is detectable as prolongation of T2 relaxation time in the gastrocnemius muscle ; the authors believe prolongation of T2 relaxation time is mainly due to increased ECSR reflecting type 2 muscle fiber atrophy.

Research Products

• [Journal Article] Steroid Myopathy : Evaluation of Fiber Atrophy with T2 Relaxation Time-Rabbit and Human Study (2006)
  • Author(s): Hatakenaka M et al.
  • Journal Title: Radiology 238 Pages: 650-657
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Steroid Myopathy : Evaluation of Fiber Atrophy with T2 Relaxation Time-Rabbit and Human Study (2006)
  • Author(s): Masamitsu Hatakenaka, MD, PhD, Hiroyasu Soeda, MD, Takashi Okafuji, MD, Hidetake Yabuuchi, MD, PhD, Satoshi Shiokawa, MD, PhD, Junji Nishimura, MD, PhD, Hiroshi Honda, MD, PhD
  • Journal Title: Radiology 238, 2 Pages: 650-657
  • Description: 「研究成果報告書概要(欧文)」より