Screening power of STIR muscle MRI in Critical illness myo-neuropathy and GBS in the ICU

Introduction Critical illness myo-neuropathy [CIMN] or ICU acquired weakness [CIMN] is a common cause of weakness in ICU patients. It is diagnosed by clinical features, nerve conduction studies and muscle/nerve biopsies. Methods The MRI muscle STIR images of 7 patients with suspected CIMN and 7 GBS patients were reviewed. Results All 7 patients with CIMN showed diffuse muscle edema, predominating in the lower limbs. Only one patient with GBS showed abnormal MRI changes (14%) and MRI was normal in 86%. The sensitivity of MRI to detect CIMN was 100%, whereas the specificity was 85.7%. Thus, the positive predictive value of MRI in this situation was 87.5% and the negative predictive value was 100%. Conclusions Muscle STIR imaging may help to differentiate between CIMN and GBS and can modify the diagnostic algorithm of CIMN.