What percentage of confirmed MS patients initially present without brain lesions on an MRI?

The correct answer is 5%. In the context of multiple sclerosis (MS), it is recognized that a small percentage of patients can present with symptoms consistent with MS but lack visible lesions on their initial MRI scans. This phenomenon can occur during the early stages of the disease when the inflammation and demyelination have not yet resulted in detectable changes in brain structure, or the lesions may be present but too small to be identified. Understanding this percentage is crucial for clinicians as it highlights the importance of a thorough clinical evaluation and monitoring over time, as subsequent MRIs may reveal lesions that were not detectable at the outset.

This statistic also underscores the complexities of diagnosing MS, emphasizing that while MRI is a valuable diagnostic tool, it is not always definitive at the first presentation of symptoms. It is important for healthcare providers to take a comprehensive approach when assessing patients for MS, considering a range of clinical findings and potentially repeating imaging studies if warranted by symptom progression.