A feasibility study for quantitative assessment of cerebrovascular malformations using flutriciclamide ([18F]GE-180) PET/MRI

Sally Ji Who Kim; Janine M Lupo; Yicheng Chen; Miguel H Pampaloni; Henry F VanBrocklin; Jared Narvid; Helen Kim; Youngho Seo

doi:10.3389/fmed.2023.1091463

A feasibility study for quantitative assessment of cerebrovascular malformations using flutriciclamide ([¹⁸F]GE-180) PET/MRI

Front Med (Lausanne). 2023 Apr 5:10:1091463. doi: 10.3389/fmed.2023.1091463. eCollection 2023.

Authors

Sally Ji Who Kim^{1

2}, Janine M Lupo¹, Yicheng Chen¹, Miguel H Pampaloni¹, Henry F VanBrocklin¹, Jared Narvid¹, Helen Kim³, Youngho Seo¹

Affiliations

¹ Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States.
² Cardiovascular Research Center, Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.
³ Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, San Francisco, CA, United States.

Abstract

Aim: Neuroinflammation plays a key role in both the pathogenesis and the progression of cerebral cavernous malformations (CCM). Flutriciclamide ([¹⁸F]GE-180) is a translocator protein (TSPO) targeting positron emission tomography (PET) tracer, developed for imaging neuroinflammation. The objectives of this study were to describe characteristics of flutriciclamide uptake in different brain tissue regions in CCM patients compared to controls, and to evaluate flutriciclamide uptake and iron deposition within CCM lesions.

Materials and methods: Five patients with CCM and six controls underwent a 60 or 90 min continuous PET/MRI scan following 315 ± 68.9 MBq flutriciclamide administration. Standardized uptake value (SUV) and standardized uptake value ratio (SUVr) were obtained using the striatum as a pseudo-reference. Quantitative susceptibility maps (QSM) were used to define the location of the vascular malformation and calculate the amount of iron deposition in each lesion.

Results: Increased flutriciclamide uptake was observed in all CCM lesions. The temporal pole demonstrated the highest radiotracer uptake; the paracentral lobule, cuneus and hippocampus exhibited moderate uptake; while the striatum had the lowest uptake, with average SUVs of 0.66, 0.55, 0.63, 0.55, and 0.33 for patient with CCM and 0.57, 0.50, 0.48, 0.42, and 0.32 for controls, respectively. Regional SUVr showed similar trends. The average SUV and QSM values in CCM lesions were 0.58 ± 0.23 g/ml and 0.30 ± 0.10 ppm. SUVs and QSM were positively correlated in CCM lesions (r = 0.53, p = 0.03).

Conclusion: The distribution of flutriciclamide ([¹⁸F]GE-180) in the human brain and CCM lesions demonstrated the potential of this TSPO PET tracer as a marker of neuroinflammation that may be relevant for characterizing CCM disease progression along with QSM.

Keywords: CCM; GE-180; PET/MRI; TSPO; flutriciclamide; neuroinflammation; quantitative susceptibility mapping (QSM); vascular malformation.

Grants and funding

U54 NS065705/NS/NINDS NIH HHS/United States