Abstract
1467
Introduction: Leukodystrophies (LDs) are a group of rare, genetic metabolic disorders characterized by loss of white matter (WM) due to myelination disorders/demyelination. Recently, we were able to show that the beta-amyloid PET Tracer 18F-Florbetaben which in addition to the actual target also binds to myelin has a great potential for improved imaging of WM diseases. The aim of this current pilot study was to evaluate for the first time the suitability of hybrid 18F-Florbetaben PET/MRI for imaging LDs. So far, six male patients with LDs (age 48±10 yrs, diagnoses: X-linked adrenoleukodystrophy (X-ALD, n = 3), Alexander disease (n = 1), hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS, n = 1) and vanishing WM disease "(VWMD, n = 1)) were examined and compared to a sex- and age-matched control group (n = 12). 90-110 min p.i. after application of about 300MBq 18F-Florbetaben, PET (SUVRs) as well as DTI MRI (FA values) images were acquired on a Siemens mMR hybrid PET/MR system. The data of the WM was regionally analyzed using the JHU WM tractography atlas (48 VOIs). Structural MRI revealed findings typical for the different LD forms. In DTI, 28% of the WM VOIs showed pathologic signals for the X-ALDs and 47% in the remaining LD patients. For late PET, this was the case in 20% and 40% of WM ROIs. Interestingly, in the X-ALD patients, the regional WM SUVRs were significantly less correlated with the regional WM FA values than in the other LDs (r̄ = 0.43 vs. r̄ = 0.88, p <0.001). From these initial results it is concluded that multimodal 18F-Florbetaben WM PET/MRI could lead, depending on the LD subtype, to a more specific characterization of LDs compared to MRI. This would also be of great interest for monitoring re-myelination therapies. To confirm this assumption, however, larger case numbers are required.
