Molecular imaging of multiple sclerosis: from the clinical demand to novel radiotracers

Abstract

Background Brain PET imaging with different tracers is mainly clinically used in the field of neurodegenerative diseases and brain tumors. In recent years, the potential usefulness of PET has also gained attention in the field of MS. In fact, MS is a complex disease and several processes can be selected as a target for PET imaging. The use of PET with several different tracers has been mainly evaluated in the research setting to investigate disease pathophysiology (i.e. phenotypes, monitoring of progression) or to explore its use a surrogate end-point in clinical trials. Results We have reviewed PET imaging studies in MS in humans and animal models. Tracers have been grouped according to their pathophysiological targets (ie. tracers for myelin kinetic, neuroinflammation, and neurodegeneration). The emerging clinical indication for brain PET imaging in the differential diagnosis of suspected tumefactive demyelinated plaques as well as the clinical potential provided by PET images in view of the recent introduction of PET/MR technology are also addressed. Conclusion While several preclinical and fewer clinical studies have shown results, full-scale clinical development programs are needed to translate molecular imaging technologies into a clinical reality that could ideally fit into current precision medicine perspectives.

In Vivo Proton Exchange Rate (kex) MRI for the Characterization of Multiple Sclerosis Lesions in Patients

“…The results of this study have shown that nonenhanced MS lesions could be further classified into two patterns by k ex mapping, suggesting that k ex may be an alternative endogenous MRI contrast for separating slowly expanding MS lesions (chronic active lesions) from inactive ones. Recently, other imaging tracers and approaches based on specific pathology were also proposed to separate the nonenhanced MS lesions, such as positron emission tomography (PET) with 11C‐(R)‐PK11195, an isoquinoline carboxamide that binds selectively to the peripheral benzodiazepine receptor (targeting activated microglia or macrophages), and SWI (targeting abnormal iron deposit) 15,38,39 . With k ex MRI (potentially targeting ROS), the stage of Gd‐negative lesions may be further characterized for the better determination of the DIT of MS lesions, encouraging further validation by comparison with other imaging approaches and studies in preclinical MS models.…”

Digital Twins for Multiple Sclerosis

“…Finally, by measuring both volumetric and dynamic quantitative means (lesions and atrophy), different MRI phenotypes of individual patients can be described by MRI-categorization ( 152 ) which could be an important component of DTMS. In addition to MRI, data obtained through other imaging biomarkers such as OCT ( 153 ) or Positron emission tomography ( 154 ) can be used as well.…”

Neuroimaging Correlates of Cognitive Dysfunction in Adults with Multiple Sclerosis

“…Reprinted from EJNMMI Radiopharmacy and Chemistry Vol. 4, Issue 1, P6, 8 April 2019 [ 120 ]. Copyright: © 2021, with permission from Springer Open.…”