White Matter Diseases with Radiologic-Pathologic Correlation

Abstract

White matter diseases include a wide spectrum of disorders that have in common impairment of normal myelination, either by secondary destruction of previously myelinated structures (demyelinating processes) or by primary abnormalities of myelin formation (dysmyelinating processes). The pathogenesis of many white matter diseases remains poorly understood. Demyelinating disorders are the object of this review and will be further divided into autoimmune, infectious, vascular, and toxic-metabolic processes. Autoimmune processes include multiple sclerosis and related diseases: tumefactive demyelinating lesions, Balo concentric sclerosis, Marburg and Schilder variants, neuromyelitis optica (Devic disease), acute disseminated encephalomyelitis, and acute hemorrhagic leukoencephalopathy (Hurst disease). Infectious processes include Lyme disease (neuroborreliosis), progressive multifocal leukoencephalopathy, and human immunodeficiency virus (HIV) encephalopathy. Vascular processes include different types of small-vessel disease: arteriolosclerosis, cerebral amyloid angiopathy, cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), primary angiitis of the central nervous system, Susac syndrome, and neurolupus. Toxic-metabolic processes include osmotic myelinolysis, methotrexate leukoencephalopathy, and posterior reversible encephalopathy syndrome. The imaging spectrum can vary widely from small multifocal white matter lesions to confluent or extensive white matter involvement. Understanding the pathologic substrate is fundamental for understanding the radiologic manifestations, and a systematic approach to the radiologic findings, in correlation with clinical and laboratory data, is crucial for narrowing the differential diagnosis. (©)RSNA, 2016.

Magnetic resonance imaging diagnosis of demyelinating diseases: An update

“…4). 45 The sensitivity of gadoliniumenhanced MRI for detecting disease activity is 5-10fold higher than that of clinical relapse, 12,46 and contrast enhancement thus offers an index of ongoing disease activity. Cortical lesions are rarely seen in NMOSD, migraine patients or healthy individuals, and are thus useful for differentiation from these diseases.…”

“…64 Tumefactive demyelinating lesions can be differentiated from tumors, such as glioblastoma or lymphoma, by the following points: (i) tumefactive lesions have less mass effect compared with tumors; 57 (ii) surrounding enhancement of tumefactive lesions is often discontinuous (open-ring sign); 64,65 (iii) a T2-hypointense rim is seen in approximately half of tumefactive lesions; 66 (iv) perilesional edema is mild or absent in 57% of tumefactive lesions; 66 (v) relative cerebral blood volume on perfusion MRI is lower in tumefactive lesions than tumors; 67 (vi) density on non-contrast-enhanced computed tomography of MRI enhancing portions is lower in tumefactive lesions than in tumors; 68 (vii) intralesional susceptibility signals (dot-like hypointensities) are not seen in tumefactive lesions, although these signals are almost always seen in glioblastomas; 69 and (viii) a dilated vein coursing within the lesion might be seen. 45 Bal o's concentric sclerosis This is a rare variant in which white matter is destroyed in concentric layers. 45 Bal o's concentric sclerosis This is a rare variant in which white matter is destroyed in concentric layers.…”

“…72,73 Bal o's concentric sclerosis has been reported in patients with NMOSD. 45,77 The cervical spinal cord is most frequently involved. 76 Spinal cord lesions Spinal cord lesions are seen in up to 90% of MS patients.…”

“…74,75 A recent study showed that Bal o's concentric sclerosis might be immunologically distinct from MS, and could be similar to NMOSD or MOG encephalomyelitis. 45 The lesions are typically well-circumscribed in the acute stage and often involve the periphery (Fig. 45,77 The cervical spinal cord is most frequently involved.…”

Pathological correlates of white matter hyperintensities in a case of progranulin mutation associated frontotemporal dementia

“…WMH appear in healthy aging as periventricular and deep white matter lesions associated with demyelination, microgliosis and vacuolation (Murray et al, 2012), and in patients with small vessel cerebrovascular disease, associated with white matter axonal loss, demyelination, gliosis, and arteriosclerosis (Wardlaw et al, 2015). WMH also occur in neuroinflammatory diseases such as multiple sclerosis (Sarbu et al, 2016), and in neurodegenerative diseases (Filley & Fields, 2016). Research into the pathological correlates of WMH in vascular dementia and sporadic and familial Alzheimer’s disease (AD) is well-established (McAleese et al, 2015, 2017; Ryan et al, 2015; Snyder et al, 2015).…”