Abstract
Purpose
We retrospectively evaluated the imaging spectrum of Pelizaeus–Merzbacher disease
(PMD) in correlation with the clinical course and genetic abnormality.
Methods
We collected the magnetic resonance imaging (MRI) findings of 19 genetically proven
PMD patients (all males, aged 0–29 years old) using our integrated web-based MRI data collection system from 14 hospitals.
The patterns of hypomyelination were determined mainly by the signals of the cerebrum,
corticospinal tract, and brainstem on T2-weighted images (T2WI). We assessed the degree
of myelination age on T1-weighted images (T1WI) and T2WI independently, and we evaluated
cerebellar and callosal atrophy. The clinical severity and genetic abnormalities (causal
mutations of the proteolipid protein gene PLP1) were analyzed together with the imaging findings.
Results
The clinical stage tended to be more severe when the whole brainstem, or corticospinal
tract in the internal capsule showed abnormally high intensity on T2WI. Diffuse T2-high
signal of brainstem was observed only in the patients with PLP1 point mutation. Myelination age “before birth” on T1WI is a second manifestation
correlated with the clinically severe phenotypes. On the other hand, eight patients
whose myelination ages were > 4 months on T1WI were associated with mild clinical phenotypes. Four of them showed
almost complete myelination on T1WI with a discrepancy in myelination age between
T1WI and T2WI. A random and patchy pattern of myelination on T2WI was noted in one
patient with PLP1 point mutation. Advanced myelination was observed in three of the seven followed-up
patients. Four patients had atrophy of the cerebellum, and 17 patients had atrophy
of the corpus callosum.
Conclusion
Our multicenter study has demonstrated a wide variety of imaging findings of PMD.
Signal intensity of brainstem and corticospinal tract of internal capsule would be
the points to presume clinical severity in PMD patients. The spectrum of MRI findings
should be kept in mind to diagnose PMD and to differentiate from other demyelinating
leukodystrophies.
Keywords
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Article info
Publication history
Published online: January 13, 2016
Accepted:
December 10,
2015
Received in revised form:
December 9,
2015
Received:
August 26,
2015
Identification
Copyright
© 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.
