The mucopolysaccharidoses: characterization by cranial MR imaging.

PURPOSE To characterize MR findings in mucopolysaccharidoses (MPS), to aid in diagnosis and categorization, and to define the role of MR in preoperative evaluation.

MATERIALS AND METHODS Six children with Hurler syndrome (MPS IH), five with Hunter syndrome (MPS II), and three with Sanfilippo A syndrome (MPS IIIA) were studied by routine T1-weighted and T2-weighted images at 1.5 T. MR findings were graded retrospectively.

RESULTS All had hallmark cribriform changes (sieve-like or multicystic) involving peri- and supraventricular, parietal, white matter (12), corpus callosum (8), and basal ganglia (4), which did not enhance. The cerebellum and brain stem were not involved with these cribriform changes. The most severe degree of cribriform changes occurred in children with Hunter and Hurler syndromes, correlating with non-central nervous system somatic involvement, but inversely related to degree of atrophy, ventricular enlargement, and white matter changes. Mental retardation was most severe in children with Hurler syndrome and correlated with chronicity of the disease. Severity of mental retardation did not correlate with severity of cribriform changes.

CONCLUSIONS Based on our observations, we postulate that in the natural course of MPS, cribriform changes occurred first, followed by white-matter changes and, last, atrophy. More severe degrees of cribriform changes plus involvement of the corpus callosum may suggest a poorer prognosis. Optimal therapeutic intervention may be at the time of cribriform changes before atrophy has occurred. MR can define and grade these changes.