Brain Magnetic Resonance in the Diagnostic Evaluation of Mitochondrial Encephalopathies |
| |
Authors: | Maria Cristina Bianchi Giuseppina Sgandurra Michela Tosetti Roberta Battini Giovanni Cioni |
| |
Institution: | (1) Department of Neuroradiology, Santa Chiara Hospital, Pisa, Italy;(2) Laboratory of Magnetic Resonance, IRCCS Stella Maris, Viale del Tirreno 331, Calambrone, 56018 Pisa, Italy;(3) Department of Developmental Neuroscience, IRCCS Stella Maris, Pisa, Italy;(4) Department of Child Neurology and Psychiatry, University of Pisa, Pisa, Italy |
| |
Abstract: | Brain MR imaging techniques are important ancillary tests in the diagnosis of a suspected mitochondrial encephalopathy since
they provide details on brain structural and metabolic abnormalities. This is particularly true in children where non-specific
neurologic symptoms are common, biochemical findings can be marginal and genetic defects may be not discovered. MR imaging
modalities include conventional, or structural, imaging (MRI) and functional, or ultrastructural, imaging (spectroscopy, MRS;
diffusion, DWI-ADC; perfusion, DSCI––ASL). Among them MRI and MRS are the main tools for diagnosis and work up of MD, and
this review will focus mainly on them. The MRI findings of MD are very heterogeneous, as they depend on the metabolic brain
defects, age of the patient, stage and severity of the disease. No correlation has been found between genetic defects and
neuroimaging picture; however, some relationships between MR findings and clinical phenotypes may be identified. Different
combinations of MRI signal abnormalities are often encountered but the most common findings may be summarized into three main
MR patterns: (i) non-specific; (ii) specific; (iii) leukodystrophic-like. Regarding the functional MR techniques, only proton
MRS plays an important role in demonstrating an oxidative metabolism impairment in the brain since it can show the accumulation
of lactate, present as a doublet peak at 1.33 ppm. Assessment of lactate should be always performed on brain tissue and on
the ventricular cerebral spinal fluid. As for MRI, metabolic MRS abnormalities can be of different types, and two distinct
patterns can be recognized: non-specific and specific. The specific metabolic profiles, although not frequent to find, are
highly pathognomonic of MD. The un-specific metabolic profiles add value to structural images in allowing to define the lesion
load and to monitor the response to therapy trials. |
| |
Keywords: | Mitochondrial disorders Magnetic Resonance Imaging Magnetic Resonance Spectroscopy Lactate |
本文献已被 PubMed SpringerLink 等数据库收录! |
|