Which imaging modality is most effective for confirming a diagnosis of multiple sclerosis?

MRI of the brain is the most effective imaging modality for confirming a diagnosis of multiple sclerosis (MS). This is primarily due to the sensitivity of MRI in detecting the characteristic lesions associated with MS, known as plaques or demyelinating lesions. These lesions typically appear as hyperintense areas on T2-weighted images or as enhancing lesions after the administration of contrast.

The ability of MRI to visualize these lesions in multiple locations in the central nervous system is pivotal in establishing the diagnosis, as MS is defined by the presence of neurological symptoms due to demyelination occurring in multiple areas over time. The McDonald criteria for MS diagnosis emphasize the importance of MRI findings in this context.

Other imaging modalities listed do not have the same level of utility for diagnosing MS. For instance, CT scans are less effective at detecting the subtle changes in the central nervous system associated with MS compared to MRI. PET scans are valuable for assessing metabolic activity and certain brain conditions but are not typically used for diagnosing MS. Transcranial Doppler ultrasound is primarily used to assess blood flow in the brain, which does not provide information relevant to diagnosing multiple sclerosis.