Brain MRI Diagnostic of Primary Angiitis of the CNS
Brain MRI Diagnostic of Primary Angiitis of the CNS
Introduction Primary angiitis of the central nervous system is a rare disease of unclear etiology. There is no single test diagnostic of primary angiitis of the central nervous system. We report an unusual pattern on brain magnetic resonance imaging that might be specific for primary angiitis of the central nervous system.
Case presentation A 47-year-old Caucasian man developed progressive bilateral hand tremor, difficulty walking, cognitive slowing and headache. A physical examination showed bilateral hand tremor with dysmetria, hyperreflexia and abnormal gait. Magnetic resonance imaging of his brain showed bilateral, symmetrical, increased intensity on T2-weighted images concurrent with linear contrast enhancement in a radial distribution throughout his white matter, sparing subcortical regions in his centrum semiovale, corona radiata, basal ganglia and brainstem. Magnetic resonance spectroscopy demonstrated elevated choline and decreased N-acetyl aspartate. Except for elevated protein and lymphocytic pleocytosis, examination of his cerebrospinal fluid showed no abnormalities. Serological tests for rheumatologic, vasculitic, paraneoplastic, infectious and peroxisomal disorders were negative. A brain biopsy revealed primary angiitis of the central nervous system. Our patient was treated with steroids and intravenous cyclophosphamide, with improvement in signs and symptoms as well as changes on magnetic resonance imaging.
Conclusion Bilateral, symmetrical, increased intensity on T2-weighted images concurrent with linear contrast enhancement in a radial distribution throughout the white matter on magnetic resonance imaging of the brain should be recognized as a feature of primary angiitis of the central nervous system, and might avoid the need for a brain biopsy to diagnose primary angiitis of the central nervous system.
Primary angiitis of the central nervous system (PACNS) can be defined as vasculitis affecting exclusively the central nervous system (CNS) without systemic disease. It is a rare disease of unclear etiology with an estimated incidence of 2.4 per 1,000,000. It manifests clinically with headache, altered mentation and a variety of focal neurological deficits. There is no specific test to diagnose PACNS. Magnetic resonance imaging (MRI) of the brain typically reveals multifocal white and gray matter signal abnormalities. Less commonly, leptomeningeal enhancement may occur. Magnetic resonance angiography is not useful in PACNS because it cannot demonstrate vasculitic changes in blood vessels smaller than the major intracranial arteries or their primary branches. Cerebral angiography can demonstrate ectasia and stenosis, however sensitivity is only 60%. Secondary causes of vasculitis need to be ruled out by thorough blood and cerebrospinal fluid (CSF) testing. A brain biopsy is still the gold standard for diagnosis of PACNS. Brain biopsies in PACNS can have a false negative rate of up to 25%. Brain biopsy is associated with a transient and permanent morbidity of 14% and 4% respectively.
We present the case of a patient with biopsy-proven PACNS in which the MRI abnormalities displayed a radial distribution of contrast enhancement, a rarely reported pattern that likely corresponds to inflamed cerebral vessels and perivascular regions.
Abstract and Introduction
Abstract
Introduction Primary angiitis of the central nervous system is a rare disease of unclear etiology. There is no single test diagnostic of primary angiitis of the central nervous system. We report an unusual pattern on brain magnetic resonance imaging that might be specific for primary angiitis of the central nervous system.
Case presentation A 47-year-old Caucasian man developed progressive bilateral hand tremor, difficulty walking, cognitive slowing and headache. A physical examination showed bilateral hand tremor with dysmetria, hyperreflexia and abnormal gait. Magnetic resonance imaging of his brain showed bilateral, symmetrical, increased intensity on T2-weighted images concurrent with linear contrast enhancement in a radial distribution throughout his white matter, sparing subcortical regions in his centrum semiovale, corona radiata, basal ganglia and brainstem. Magnetic resonance spectroscopy demonstrated elevated choline and decreased N-acetyl aspartate. Except for elevated protein and lymphocytic pleocytosis, examination of his cerebrospinal fluid showed no abnormalities. Serological tests for rheumatologic, vasculitic, paraneoplastic, infectious and peroxisomal disorders were negative. A brain biopsy revealed primary angiitis of the central nervous system. Our patient was treated with steroids and intravenous cyclophosphamide, with improvement in signs and symptoms as well as changes on magnetic resonance imaging.
Conclusion Bilateral, symmetrical, increased intensity on T2-weighted images concurrent with linear contrast enhancement in a radial distribution throughout the white matter on magnetic resonance imaging of the brain should be recognized as a feature of primary angiitis of the central nervous system, and might avoid the need for a brain biopsy to diagnose primary angiitis of the central nervous system.
Introduction
Primary angiitis of the central nervous system (PACNS) can be defined as vasculitis affecting exclusively the central nervous system (CNS) without systemic disease. It is a rare disease of unclear etiology with an estimated incidence of 2.4 per 1,000,000. It manifests clinically with headache, altered mentation and a variety of focal neurological deficits. There is no specific test to diagnose PACNS. Magnetic resonance imaging (MRI) of the brain typically reveals multifocal white and gray matter signal abnormalities. Less commonly, leptomeningeal enhancement may occur. Magnetic resonance angiography is not useful in PACNS because it cannot demonstrate vasculitic changes in blood vessels smaller than the major intracranial arteries or their primary branches. Cerebral angiography can demonstrate ectasia and stenosis, however sensitivity is only 60%. Secondary causes of vasculitis need to be ruled out by thorough blood and cerebrospinal fluid (CSF) testing. A brain biopsy is still the gold standard for diagnosis of PACNS. Brain biopsies in PACNS can have a false negative rate of up to 25%. Brain biopsy is associated with a transient and permanent morbidity of 14% and 4% respectively.
We present the case of a patient with biopsy-proven PACNS in which the MRI abnormalities displayed a radial distribution of contrast enhancement, a rarely reported pattern that likely corresponds to inflamed cerebral vessels and perivascular regions.
