TY - JOUR
T1 - Steroid myopathy
T2 - Evaluation of fiber atrophy with T2 relaxation time - Rabbit and human study
AU - Hatakenaka, Masamitsu
AU - Soeda, Hiroyasu
AU - Okafuji, Takashi
AU - Yabuuchi, Hidetake
AU - Shiokawa, Satoshi
AU - Nishimura, Junji
AU - Honda, Hiroshi
PY - 2006/2
Y1 - 2006/2
N2 - 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 that 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 either muscle 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.
AB - 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 that 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 either muscle 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.
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U2 - 10.1148/radiol.2381041720
DO - 10.1148/radiol.2381041720
M3 - Article
C2 - 16371576
AN - SCOPUS:31144433581
SN - 0033-8419
VL - 238
SP - 650
EP - 657
JO - Radiology
JF - Radiology
IS - 2
ER -