Background: Mitochondrial cytopathies (MCs) are a heterogeneous group of clinical entities, some of which have classic phenotypes. Magnetic resonance imaging (MRI) has been reported to be helpful in the diagnosis of MC.

Objective: To correlate the most common brain MRI findings reported in patients with MC with the clinical findings in patients in different MC subgroups.

Design: Case series.

Setting: Patients with MCs seen at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubiran, Mexico City, Mexico.

Patients: Twenty-one patients with MC with the following phenotypes: chronic progressive external ophthalmoplegia (n = 7), Kearns-Sayre syndrome (n = 7), mitochondrial neurogastrointestinal encephalopathy (n = 6), and myoclonic epilepsy with ragged red fiber myopathy (n = 1).

Results: Brain MRI abnormalities were found in 20 (95%) of 21 patients. The most frequent abnormalities were widespread white matter hyperintensity in 19 patients (90%), supratentorial cortical atrophy in 18 patients (86%), and cerebellar atrophy in 13 patients (62%). Widespread white matter hyperintensity (P<.001) and supratentorial cortical atrophy (P = .001) were each correlated significantly with MC. Subsequent subgroup analyses showed that the absence of basal ganglia hyperintensity was correlated with Kearns-Sayre syndrome (P < .001) and the presence of supratentorial cortical atrophy was correlated with mitochondrial neurogastrointestinal encephalopathy (P = .005).

Conclusions: The presence of widespread white matter hyperintensity and/or supratentorial cortical atrophy in brain MRI may help to establish the diagnosis of MC. The radiologist has a role to play in the workup of MC by confirming the diagnosis and possibly distinguishing different subgroups of MC.