Brain and Spinal MR Imaging Findings in Mucopolysaccharidoses: A Review

Abstract

SUMMARY: MPS represents a group of rare hereditary disorders characterized by multisystem involvement due to intralysosomal GAG accumulation. Among various tissues, both the central and peripheral nervous system are affected in almost all types of the disease. Thus, brain and spinal MR imaging are valuable tools for the assessment of neurologic involvement, and there is evidence that they might be reliable markers demonstrating disease severity and efficacy of treatment options currently used in patients with MPS. We aimed to review the most prominent MR imaging features of patients with MPS, paying attention to the physiopathologic mechanisms responsible for these alterations. Along with the description of neuroimaging findings, existing data in relation to their correlation with the severity of neurologic involvement is discussed, while another topic of great importance is the effect of various therapeutic regimens in the progression of brain and spinal MR imaging alterations. Finally, recent data concerning MR spectroscopy studies in MPS are also critically discussed. ABBREVIATIONS:ERT ϭ enzyme replacement therapy; GAG ϭ glycosaminoglycan; HSCT ϭ hematopoietic stem cell transplantation; MPS ϭ mucopolysacchari-

The role of brain barriers in fluid movement in the CNS: is there a ‘glymphatic’ system?

“…Finally, it bears noting that an enlarged PVS has been identified (typically associated with larger caliber vessels such as perforating arterioles and venules) in a number of clinical MRI studies of patients with traumatic brain injuries [93], acute ischemic stroke [53], and multiple different types of mucopolysaccharidoses [115,198]. Enlarged perivascular spaces might simplistically suggest either increased water secretion by the BBB, decreased clearance of CSF, increased resistance to the circulation/transport and/or drainage of perivascular fluid, or a combination of all of the above.…”

Avaliação neurológica e de neuroimagem em pacientes com mucopolissacaridoses

“…However, some positive correlation attempts between imaging abnormalities and clinical symptoms have been failed. White matter lesions, dilated perivascular spaces and hydrocephalus are classically reported, while arachnoid cysts caused by meningeal GAG deposition are occasionally seen [ [23][24][25]. We also have noticed a questionable concept in the literature that MPS VI patients have no brain involvement or their lesions might not become apparent until adulthood [25].…”

“…MRI findings in patients with MPS VI also include pituitary sella abnormalities, dilatation of venous sinuses and thickening of the diploe, optic canal stenosis and optic nerve atrophy [18,25,27].…”

“…White matter lesions, dilated perivascular spaces and hydrocephalus are classically reported, while arachnoid cysts caused by meningeal GAG deposition are occasionally seen [ [23][24][25]. We also have noticed a questionable concept in the literature that MPS VI patients have no brain involvement or their lesions might not become apparent until adulthood [25]. In our small sample however, we have shown even in normal MPS VI patients, abnormalities in ventricular system (3/6), white matter (3/6) and perivascular spaces (3/6) were seen.…”

“…This overflow impairment in association with meningeal deposit of GAG may lead to ventricular enlargement and communicant hydrocephalus [26]. Spinal MRI features associated to MPS are canal stenosis with or without compressive myelopathy, odontoid hypoplasia, atlantoaxial instability, dural thickening, vertebral bodies degenerative signs and Smchö rl's nodes (intrasomatic disks abnormalities) [25]. As spinal cord compression onset is unknown for most patients and this abnormality has potentially risk of sudden death, physiopathology and treatment of this condition have been broadly discussed in literature [5].…”