Which findings on brain MRI are characteristic of multiple sclerosis (MS)?

Updated: Mar 27, 2019
  • Author: James A Wilson, MD, MSc, FRCPC; Chief Editor: James G Smirniotopoulos, MD  more...
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Answer

Answer

Because of the inflammation and breakdown of the blood-brain barrier in MS lesions, the presence of extravascular fluid leads to hyperintensity on T2-weighted images. Thus, in a patient with MS, MRI scans typically demonstrate more than 1 hyperintense white matter lesion. [33, 34, 35, 36, 37]

Lesions may be observed anywhere in the CNS white matter, including the supratentorium, infratentorium, and spinal cord; however, more typical locations for MS lesions include the periventricular white matter, brainstem, cerebellum, and spinal cord. Ovoid lesions perpendicular to the ventricles are common in MS and occasionally are called Dawson bars or fingers, which occur along the path of the deep medullary veins. Perhaps the most specific lesions in MS are noted in the corpus callosum at the interface with the septum pellucidum. [38]

(See the MRI scans below.)

Sagittal T1-weighted MRI depicts multiple hypointe Sagittal T1-weighted MRI depicts multiple hypointense lesions in the corpus callosum; this finding is characteristic of multiple sclerosis.
Axial T2-weighted MRI in a patient with multiple s Axial T2-weighted MRI in a patient with multiple sclerosis demonstrates numerous white matter plaques in a callosal and pericallosal white matter distribution.
Axial T1-weighted, gadolinium-enhanced MRI in a pa Axial T1-weighted, gadolinium-enhanced MRI in a patient with multiple sclerosis demonstrates several intensely enhancing pericallosal white matter lesions compatible with active disease.
Axial diffusion-weighted MRI in a patient with mul Axial diffusion-weighted MRI in a patient with multiple sclerosis shows several hyperintense lesions, a feature of inflammatory disease activity.
Axial proton density–weighted MRI through the post Axial proton density–weighted MRI through the posterior fossa in a patient with multiple sclerosis demonstrates multiple bright foci in the brainstem and cerebellum. Proton density–weighted sequences are highly sensitive for the detection of plaques in multiple sclerosis, especially in the posterior fossa.
Axial proton density–weighted MRI demonstrates mul Axial proton density–weighted MRI demonstrates multiple lesions in a distribution characteristic of multiple sclerosis. Specifically, the periventricular lesions and the more peripheral white matter lesions near the gray matter–white matter junction are typical MRI findings in multiple sclerosis.
Axial T1-weighted, gadolinium-enhanced MRI in a pa Axial T1-weighted, gadolinium-enhanced MRI in a patient with multiple sclerosis depicts enhancement of a plaque in the right temporo-occipital lobe, signifying disease activity. Note the C-shaped, or arclike, enhancement, which is fairly characteristic of multiple sclerosis.
Sagittal proton density–weighted MRI in a patient Sagittal proton density–weighted MRI in a patient with multiple sclerosis demonstrates the characteristic corpus callosal and pericallosal white matter lesions.
Axial T1-weighted, gadolinium-enhanced MRI in a pa Axial T1-weighted, gadolinium-enhanced MRI in a patient with multiple sclerosis depicts several enhancing lesions, at least 2 of which show characteristic C-shaped, or arclike, peripheral enhancement.
Axial diffusion-weighted MRI in a patient with mul Axial diffusion-weighted MRI in a patient with multiple sclerosis shows several hyperintense lesions, a feature of inflammatory disease activity.

Proton density (PD)–weighted MRI has an advantage over standard T2 imaging, because on PD series, MS lesions remain hyperintense, while the CSF signal is suppressed. Therefore, the lesions are easily identified. Depending on the PD technique, the CSF signal is suppressed to a variable degree, rendering it isointense to hypointense relative to the brain parenchyma. This sequence results in substantial suppression of Virchow-Robin spaces, which are perivascular CSF spaces that may penetrate to the subcortical white matter. These spaces may appear as hyperintense spots on standard T2-weighted MRI scans.

Compared with other techniques, nonenhanced T1-weighted MRI is far less sensitive in detecting MS lesions. Acute lesions usually are not depicted at all. With T1-weighted MRI, the clinician can gain a general appreciation of the global cerebral atrophy that occurs with advanced chronic MS. Global atrophy has been suggested to have the strongest imaging correlation with disability.

Chronic MS lesions usually result in localized leukomalacia, and they may appear as hypointense lesions that represent loss of tissue.

Gadolinium-enhanced T1-weighted MRI scans can depict acute, active MS lesions. These appear as enhancing white matter lesions; the presence of an enhancing lesion has been shown to increase the specificity for MS. [5, 28]


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