MRI Interpretation of T2/FLAIR Hyperintensities in Subcortical and Deep White Matter

Key Imaging Features

The American College of Radiology suggests that small lesion size, with multiple 0.3 cm lesions and one 0.6 cm periventricular lesion, is characteristic of age-related cerebral small vessel disease 1, 2
The presence of lesions in subcortical/deep white matter and periventricular regions in frontal and temporal/occipital lobes is consistent with cerebral small vessel disease 3, 4
The absence of restricted diffusion argues against acute ischemia, as noted by the Journal of the American College of Radiology 5
The absence of enhancement excludes active inflammation or breakdown of the blood-brain barrier, according to the Brain journal 4

The most common cause of scattered T2/FLAIR hyperintensities in subcortical and deep white matter is age-related cerebral small vessel disease, particularly when lesions are small, non-enhancing, and located in deep white matter, as stated by the Journal of the American College of Radiology 5
Lesions in deep and periventricular white matter are characteristic of ischemic small vessel disease, as reported by the Brain journal 3, 5

Multiple Sclerosis (MS) should be considered if there are specific clinical symptoms or if lesions meet specific imaging criteria, such as lesions ≥3 mm in longest axis, as suggested by the Brain journal 1, 2
MS diagnosis requires typical lesions in at least two characteristic regions: periventricular, juxtacortical, infratentorial, or spinal cord, according to Praxis Medical Insights 6
CADASIL (Cerebral Autosomal Dominant Arteriopathy) should be considered if there is a specific imaging pattern, such as bilateral lesions involving anterior temporal pole, external capsule, basal ganglia, and/or pons, as noted by the Brain journal 4

The Journal of the American College of Radiology recommends that the absence of T1 hypointensity suggests less severe tissue damage and potentially reversible injury rather than completed infarction 5

Praxis Medical Insights suggests that only pursue MS evaluation if clinical symptoms suggest demyelinating disease, patient is younger (<50 years) without vascular risk factors, or follow-up imaging shows new lesions in characteristic MS locations 6
The Brain journal recommends that lesions meet size criteria (≥3 mm) for MS diagnosis 1, 2

Praxis Medical Insights warns against over-interpreting small white matter hyperintensities as MS without clinical correlation and characteristic imaging patterns 6
The Journal of the American College of Radiology advises that not all white matter hyperintensities require extensive workup; clinical context determines next steps 5
The Brain journal notes that lesions <3 mm may not meet diagnostic criteria for MS even if other features are present 1, 2