Cerebrospinal fluid pleocytosis in multiple sclerosis patients with lesions showing reduced diffusion

Area of Science:

• Neurology
• Radiology
• Neuroimmunology

Background:

• Acute lesions in multiple sclerosis (MS) can exhibit reduced apparent diffusion coefficient (ADC) on magnetic resonance imaging (MRI), but the cause is unknown.
• Understanding this phenomenon is crucial for diagnosing and monitoring MS activity.

Purpose of the Study:

• To investigate the relationship between cerebrospinal fluid (CSF) findings and diffusion MRI characteristics of acute lesions in patients with MS or clinically isolated syndrome (CIS).
• To explore the potential mechanisms underlying reduced ADC values in acute MS lesions.

Main Methods:

• Compared CSF analysis with diffusion MRI signal characteristics in 25 patients with MS or CIS.
• Analyzed intralesional ADC values and CSF pleocytosis in patients presenting early after symptom onset.

Main Results:

• A reduced intralesional ADC value (-15% to -51%) was observed in 9 out of 25 patients within 1-4 days of symptom onset.
• This ADC reduction was accompanied by marked CSF pleocytosis (11-46 leukocytes/µl).
• Both reduced ADC and CSF pleocytosis were transient phenomena observed only early after symptom onset.

Conclusions:

• Reduced ADC in acute MS lesions may be linked to an aggressive inflammatory process, as suggested by CSF pleocytosis.
• These findings indicate that ADC reduction and CSF pleocytosis are typically early and transient features of acute MS lesions.