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Co-analysis of Brain Structure and Function using fMRI and Diffusion-weighted Imaging
Published on: November 8, 2012
Diffusion Tensor Imaging and Fiber Tractography Analysis in Patients with Pelizaeus-Merzbacher Disease
Hacı Ali Erdoğan1, Alp Dinçer2, Pınar Topaloğlu3
1Bakırköy Dr. Sadi Konuk Training and Research Hospital, Department of Neurology Istanbul, Türkiye.
Introduction:
Pelizaeus-Merzbacher Disease (PMD) is a hypomyelinating disorder with X-linked recessive inheritance caused by mutations in the proteolipid protein 1 (PLP1) gene on chromosome Xq22. In the early stages of PMD, head tremor and pendular nystagmus are observed, while in the later stages, psychomotor developmental delay, choreoathetosis, ataxia, and spasticity are added to the clinical presentation. This study aimed to investigate the relationship between diffusion tensor imaging-fiber tractography (DTI-FT) findings, the clinical and pathogenetic features in PMD patients.
Methods:
Nineteen patients diagnosed with PMD between 1995-2006 and 19 healthy controls were included in our study. Both patient and control groups underwent 3 Tesla Magnetic Resonance Imaging (MRI), DTI, and FT examinations. By using DTI regions of interest (ROI) were drawn in the corticospinal tract, right inferior occipitofrontal fasciculus (RIOFF), middle cerebellar peduncle, and right cingulum. The mean fractional anisotropy (FA) values of the tractographies which obtained from the ROIs were calculated. Clinical and genetic features were compared with mean FA values.
Results:
Significant differences were found between the PMD and control groups in the FA values of the corticospinal tract (CST), corpus callosum, right inferior occipitofrontal fasciculus, middle cerebellar peduncle and right cingulum. This patient group had significantly higher FA values. Patients with severe disabilities showed marked reductions in anisotropy at the corticospinal tract level.
Conclusion:
The significantly reduced FA values in the white matter regions in the patient group are sufficient to suggest predominantly white matter involvement in PMD. The markedly lower CST FA values in patients with severe disabilities indicate that CST may serve as an important localization for determining disease severity. Studies using DTI-FT in similar patient groups will non-invasively enhance our understanding of structural differences.
Insights
Pelizaeus-Merzbacher Disease (PMD) involves white matter abnormalities, as shown by diffusion tensor imaging-fiber tractography (DTI-FT). Reduced fractional anisotropy in the corticospinal tract correlates with disease severity in PMD patients.
Area of Science:
- Neurology
- Radiology
- Genetics
Background:
- Pelizaeus-Merzbacher Disease (PMD) is an X-linked hypomyelinating disorder caused by PLP1 gene mutations.
- Clinical presentation includes tremor, nystagmus, developmental delay, and spasticity.
Purpose of the Study:
- To investigate the relationship between DTI-FT findings and clinical/pathogenetic features in PMD.
- To assess white matter structural differences in PMD patients using advanced imaging techniques.
Main Methods:
- Nineteen PMD patients and 19 controls underwent 3 Tesla MRI, DTI, and FT.
- Regions of interest were defined in key white matter tracts, including the corticospinal tract.
- Mean fractional anisotropy (FA) values were calculated and compared between groups.
Main Results:
- Significant differences in FA values were observed in multiple white matter tracts between PMD patients and controls.
- PMD patients exhibited significantly reduced FA values, indicating white matter involvement.
- Severe disabilities in PMD patients correlated with markedly reduced FA values in the corticospinal tract.
Conclusions:
- DTI-FT reveals predominantly white matter involvement in PMD.
- Corticospinal tract FA values may serve as a biomarker for PMD disease severity.
- DTI-FT offers a non-invasive method to understand structural changes in PMD.
