Magnetic resonance imaging of skeletal muscles in idiopathic inflammatory myopathies of adults

Abstract

The purpose of the study was to describe typical MRI findings in various types of idiopathic inflammatory myopathies in adulthood and to correlate the MRI with histopathological and electromyographic findings, and the serum creatine kinase (CK) activity. A third goal was to assess the diagnostic value of the use of gadolinium-DTPA (Gd-DTPA). Fifty-eight patients (35 women, 23 men), aged 21-83 years (median age 59 years), suffering from idiopathic myositides (13 with acute and 45 chronic diseases; 25 with polymyositis, 14 with dermatomyositis, 8 with granulomatous and 11 with inclusion body myositides) were examined with MRI. Seventeen of them received an intravenous infusion of Gd-DTPA. Histopathological and MRI findings of 21 muscles of 18 patients were compared. MRI of skeletal muscles showed abnormal signal intensities in 56 (96.6%) of the 58 patients. MRI abnormalities were found more often than elevated CK activity (P < 0.001). The hyperintensity of T2-weighted images was more conspicuous than on T1-weighted images in 26 (44.8%) patients, indicating oedema-like abnormalities. MRI of 50 (86.2%) patients showed fat replacement. In acute myositides, oedema-like abnormalities were more often visible and in muscle lipomatosis less often visible than in chronic diseases (P < 0.05 each). In dermatomyositis oedema-like abnormalities were more and lipomatosis less frequent than in the other types of myositis (P < 0.005) and correlated with the acuteness of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of muscle involvement in inclusion body myositis: Clinical and magnetic resonance imaging study

“…They found changes predominantly in the anterior compartment of the thigh in IBM, but did not present quantitative data on T2 relaxation times. Reimers et al 25 also studied a mixed group of patients with IBM and other inflammatory myopathies and presented only semiquantitative data on changes in signal intensity on T2-weighted images. Sekul and Dalakas 26 presented nonquantitative observations on T1-and STIR-weighted images of the forearm muscles in a group of patients with sIBM and emphasized the involvement of the flexor digitorum profundus and relative sparing of the flexor digitorum sublimis.…”

Whole-Body MRI for Evaluation of the Entire Muscular System

“…Muscle fibers are grouped into fascicles, and the fascicles are grouped into muscles. At MR imaging, skeletal muscle has an intermediate to long T1 and short T2 relaxation time and so it has signal intensity higher than water and lower than fat on T1-weighted imaging and much lower than water and fat on T2-weighted imaging (Reimers et al 1994;Fleckenstein and Reimers 1996). Normal muscle fascicles are separated from one another by fat-containing septa, thus, normal skeletal muscle has a feathery or marbled appearance on non-fat suppressed images (Costa et al 2012).…”

Diagnosis of idiopathic myositis: value of 99m technetium pyrophosphate muscle scintigraphy and magnetic resonance imaging in targeted muscle biopsy

“…In addition to these criteria, technetium pyrophosphate scintigraphy ( 99m Tc-PYP) [17,18] and magnetic resonance imaging (MRI) [19,20] have been reported to be useful in the dignosis of myositis by demonstrating sites indicative of muscle inflammation. So far, only limited information on the value of either diagnostic procedure in the detection of histopathologic muscle inflammation is available.…”