Date: Sunday, October 21, 2018
Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Background/Purpose: Muscle ultrasound (MUS) offers a cost effective, accessible option for detection of muscle inflammation and atrophy in patients with Idiopathic Inflammatory Myopathies (IIM). The goal of this study was to compare several MUS parameters in patients with IIM vs. healthy controls (CON), to examine their correlates with measures of IIM disease activity and damage, and to compare the sensitivity and specificity of MUS to magnetic resonance imaging (MRI).
Methods: MUS of the right mid-rectus femoris (RF) using the Acuson Sequoia was performed in 26 IIM patients (PTS) meeting probable or definite Bohan and Peter criteria (20 with juvenile dermatomyositis [JDM], 2 DM, 2 juvenile polymyositis [PM], and 2 juvenile overlap myositis) and compared to 30 age-, gender- and race-matched controls (CON). MUS parameters of IIM patients, evaluated by digital image processing software within regions of interest identified by radiologists, were correlated (Spearman rank) with IIM disease activity and damage assessments and semi-quantitative MRI short tau inversion recovery (STIR) and T1 scores. The area under the receiver operating characteristic (ROC) was used to compare sensitivity and specificity of MUS to MRI.
Results: The median age at diagnosis of IIM was 12.8 years, 69% were female, 77% were Caucasian. The median age of CON was 14.5 years, with similar genders and races as PTS. Median MD Global Disease Activity was 4.0 cm (10 cm VAS) and MD Global Disease Damage was 1.8 cm. There was a significant increase in RF echogenicity [median 48.5 in PTS vs. 39.3 CON, p=0.0004], but decrease in RF area (median 9.0 PTS vs 10.6 CON, p=0.038), RF contracted area (median 7.9 PTS vs. 9.9 CON, p=0.005) and vascular power Doppler (median 4.0 PTS vs. 1.0 CON, p=0.032) in IIM vs. CON. Mean echogenicity of MUS correlated with MD Global Activity (rs 0.46, p=0.04) and inversely with proximal MMT (rs -0.54, p=0.01). RF area inversely correlated with MD global activity (rs -0.46, p= 0.04) and correlated with proximal MMT (rs 0.57, p=0.009). Contracted RF area inversely correlated with MD Global Activity (rs -0.56, p=0.009) and correlated with proximal MMT (rs 0.76, p<0.0001) and CMAS (rs 0.80, p <0.0001). MUS echogenicity correlated with both STIR (rs 0.44 p=0.03) and T1 MRI sequences (rs 0.46, p=0.02). T1 MRI correlated with the difference in RF area between the contracted and resting states (rs 0.67, p=0.002). Several MUS measures inversely correlated with muscle atrophy on T1 MRI, including vascular color Doppler (rs -0.49, p=0.01), RF contracted mean AP area (rs -0.57, p=0.003), and RF contracted area (rs -0.43, p=0.03). The area under the curve by ROC analysis of MUS echogenicity vs. STIR MRI was 0.75, and using an average of STIR and T1 MRI, improved to 0.81.
Conclusion: Several MUS parameters of RF differed between IIM vs. CON, including increased echogenicity, decreased resting and contracted area, and decreased vascular power Doppler. MUS also had moderate to strong construct validity with IIM disease activity, strength and MRI measures. MUS echogenicity has strong sensitivity and specificity compared to MRI, and is a promising imaging modality for IIM patients.
To cite this abstract in AMA style:McBride E, Mamyrova G, Harris-Love M, Premkumar A, Koziol D, Yao J, Yao L, Shrader J, Jain M, Curiel R, Miller FW, Rider LG. Preliminary Validation of Rectus Femoris Muscle Ultrasound in Idiopathic Inflammatory Myopathy Patients [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 10). https://acrabstracts.org/abstract/preliminary-validation-of-rectus-femoris-muscle-ultrasound-in-idiopathic-inflammatory-myopathy-patients/. Accessed October 25, 2021.
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