PET visualization of microglia in multiple sclerosis patients using [11C]PK11195

• Published in: European journal of neurology Vol. 10; no. 3; pp. 257 - 264
• Main Authors: Debruyne, J. C., Versijpt, J., Van Laere, K. J., De Vos, F., Keppens, J., Strijckmans, K., Achten, E., Slegers, G., Dierckx, R. A., Korf, J., De Reuck, J. L.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-05-2003
• Subjects: Adult; Age Factors; Antineoplastic Agents - metabolism; Antineoplastic Agents - therapeutic use; Brain Mapping; Cohort Studies; Female; Humans; inflammation; Isoquinolines - metabolism; Isoquinolines - therapeutic use; Magnetic Resonance Imaging - methods; Male; microglia; Microglia - diagnostic imaging; Microglia - metabolism; Middle Aged; multiple sclerosis; Multiple Sclerosis - diagnostic imaging; Multiple Sclerosis - metabolism; Multiple Sclerosis - physiopathology; Parietal Lobe - metabolism; Parietal Lobe - pathology; Parietal Lobe - physiopathology; peripheral benzodiazepine receptor; PK11195; positron emission tomography; Radioligand Assay - methods; Recurrence; Thalamus - diagnostic imaging; Thalamus - metabolism; Thalamus - pathology; Tomography, Emission-Computed - methods
• ISSN: 1351-5101; 1468-1331
• DOI: 10.1046/j.1468-1331.2003.00571.x

Activated microglia are involved in the immune response of multiple sclerosis (MS). The peripheral benzodiazepine receptor (PBR) is expressed on microglia and up‐regulated after neuronal injury. [11C]PK11195 is a positron emission tomography (PET) radioligand for the PBR. The objective of the present study was to investigate [11C]PK11195 imaging in MS patients and its additional value over magnetic resonance imaging (MRI) concerning the immuno‐pathophysiological process. Seven healthy and 22 MS subjects were included. Semiquantitative [11C]PK11195 uptake values were assessed with normalization on cortical grey matter. Uptake in Gadolinium‐lesions was significantly increased compared with normal white matter. Uptake in T2‐lesions was generally decreased, suggesting a PBR down‐regulation. However, uptake values increased whenever a clinical or MR‐relapse was present, suggestive for a dynamic process with a transient PBR up‐regulation. During disease progression, an increase of normal‐appearing white matter (NAWM) uptake was found, propagating NAWM as the possible real burden of disease. In conclusion, [11C]PK11195 and PET are able to demonstrate inflammatory processes with microglial involvement in MS.