P.85 - Usefulness of MRI in cases of hyperCKemia

Abstract

Muscle MRI (mMRI) is an important tool for diagnosis and management in myopathies. However, its utility has not been comprehensively assessed on the study of asymptomatic or paucisymptomatic hyperCKemia (HCK). The objective is to evaluate the mMRI diagnostic performance and its predictive capacity in a large series of patients with HCK. We perform total body mMRI in 142 patients (80% male) diagnosed of asymptomatic or paucisymptomatic HCK (CK > 250 IU/L). T1 and STIR sequences were obtained on the axial plane from 6 segments (neck, shoulder girdle, trunk, pelvic, thighs and legs). Fat replacement was graded according to Mercuri scale (grades 1–4). All patients were studied using a protocol including blood enzymatic studies, muscle biopsy and genetic tests including dystrophin MLPA and iontorrent LGMD genepanel. Diagnoses were as follow: 7 dystrophinopathies, 37 LGMDs, 5 inflammatory myopathies, 6 glycogenosis, 6 neurogenic, 7 myofibrillar myopathies and 70 idiopathic. mMRI alterations were found in 67% of the patients, 34% of them showed a generalized muscle involvement and 33% a focal pattern. The most marked changes were located in pelvic, thigh and leg muscles. A specific mMRI signature of HCK was not found but a few profiles oriented to some diagnoses (dystrophin, LGMDs and glycogenosis). The extent of mMRI involvement was not length dependent but higher degree of mMRI involvement was detected in patients who developed long-term weakness. MRI can help to the diagnosis of HCK and can give information about prognosis. Its inclusion in an HCK algorithm investigation may help to optimize the diagnostic process.