Abstract Details

Title Less fatty infiltration of the quadriceps muscles in dysphagic inclusion body myositis

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) P15 - Poster Session 15 (5:30 PM-6:30 PM)

Poster/Presentation
Number 11-006

Background IBM having CP bar could be a subset of the patients, who showed dysphagia predominantly. The muscle involvement in dysphagic IBM patients has not been known well.

Objective

To characterize IBM with cricopharyngeal (CP) bar (IBM-CPB(+)), focusing on muscle Magnetic Resonance Imaging (MRI) in comparison with IBM without CP bar (IBM-CPB(-)).

Design/Methods In this study, 18 IBM-CPB(+) and 31 IBM-CPB(-) were included. Muscle MRI examinations for upper legs or upper arms were performed on a 3-T MRI system at diagnosis. The images were quantitatively analyzed using ImageJ software. Muscles were manually segmented. The examined muscles in the axial section were: (i) upper leg: rectus femoris (RF), vasti (vastus lateralis [VL], intermedius [VI], and medialis [VM]), sartorius, gracilis, semimembranosus and semitendinosus, biceps femoris, and adductors (adductor brevis, longus and magnus); (ii) shoulder region: deltoid, supraspinatus, infraspinatus, and subscapularis; and (iii) upper arm: biceps and triceps. The intramuscular adipose tissue (IntraMAT) content on T1-weighted MR images and the intramuscular edema-like changes (IntraMEC) content on STIR images were calculated for each muscle.

Results

Clinical features of IBM-CPB(+) were elderly onset and obstruction-related dysphagia. The levels of CK, IBMFRS, and the 6-minute walk test in IBM-CPB(+) was comparable to IBM-CPB(-). On MRI, IntraMAT content of the quadriceps muscles in IBM-CPB(+) was less than IBM-CPB(-): RF, 0% vs 2.8% (p=0.04); VL, 17.6% v.s. 61.9% (p=0.007); VI, 8.0% v.s. 40.9% (p=0.002); and VM, 3.3% v.s. 36.8% (p=0.003). There was no significant difference in IntraMEC content of the upper legs, and IntraMAT and IntraMEC content of the upper arm between IBM-CPB(+) and IBM-CPB(-).

Conclusions IBM-CPB(+) showed muscle inflammation but less fatty infiltration of the quadriceps muscles than IBM-CPB(-) on MRI.

Authors/Disclosures
Kenichiro Taira, MD, PhD (Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology) PRESENTER	Dr. Taira has nothing to disclose.
Madoka Mori-Yoshimura, MD, PhD (National Center Hospital, National Center of Neurology and Psychiatry)	Dr. Mori-Yoshimura has nothing to disclose.
Toshiyuki Yamamoto (National Center Hospital, National Center of Neurology and Psychiatry)	Dr. Yamamoto has nothing to disclose.
	No disclosure on file
Ichizo Nishino, MD, PhD, FAAN (National Institute of Neuroscience, NCNP)	The institution of Dr. Nishino has received research support from AMED.
Yuji Takahashi, MD, PhD (National Center of Neurology and Psychiatry)	The institution of Dr. Takahashi has received research support from Nihon Medi-Physics Co. Limit.. The institution of Dr. Takahashi has received research support from Takeda Pharmaceutical Company Limited.