This report highlights the presence of extensive cerebral dysfunction in a patient with cerebral mitochondrial disorder.
The patient is a 10-year-old girl with a history of hemiparesis, encephalopathy, developmental delay, and seizures. She underwent 1H magnetic resonance spectroscopic imaging, magnetic resonance imaging (MRI), and high-resolution regional cerebral blood flow (rCBF) obtained through Tc-99m ethylcysteinate dimer brain SPECT. After 1 year, a follow-up rCBF SPECT scan was obtained.
Magnetic resonance spectroscopy showed a relative decrease in N-acetylaspartate in the cerebellar hemispheres and relatively increased choline, indicating increased cerebellar lipid accumulation. MRI findings showed a lack of myelination in the posterior limb of the internal capsule, whereas rCBF showed reduction in the associated gray matter. On parametric statistical analysis of rCBF using 3D-SSP, the reduction in blood flow in both initial and follow-up scans was found to be greater than 3 standard deviations below the mean in the occipital lobes. Cerebral dysfunction could be attributed to an intrinsic abnormality of the gray matter or diaschisis from dysfunctional white matter.
Quantitative assessment of imaging in patients with suspected mitochondrial disorder with only subtle changes on MRI may be better characterized using rCBF and parametric statistical mapping to localize and assess the extent of damage in the brain. Its utility is also valuable when follow-up scans are performed to determine the progression of cerebral change.
From the Department of Radiology, Division of Nuclear Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
Received for publication October 11, 2007; revision accepted March 15, 2008.
Reprints: James M. Mountz, MD, PhD, Division of Nuclear Medicine, University of Pittsburgh Medical Center, PET Facility, B-932, 200 Lothrop Street, Pittsburgh, PA 15213. E-mail: email@example.com.