Abstract
1079
Introduction: QSM detects paramagnetic signals mainly caused by iron accumulation in the brain. Recently, we found different QSM patterns in dementia patients depending on the presence of β-amyloid pathology [1]. A post-mortem study demonstrated a lower iron load in the caudate nucleus in specific variants of FTD [2]. Thus, the aim of this study was to investigate whether these iron changes are detectable in bvFTD patients using QSM. Methods: 17 patients with clinical diagnosis of bvFTD (63±11yrs; m:10) and 11 healthy controls (HCs) (65±3yrs; m:4) were examined using dual-time point (perfusion and β-amyloid (n=13, all β-amyloid PET negative) or tau (n=4) pathology) PET/MRI (Siemens Biograph mMR). QSM data were determined using the 3D high-resolution spoiled gradient echo sequence. The QSM signals in the basal ganglia and the relative perfusion in the frontotemporal cortical regions were analyzed using PMOD. Results: QSM values of the bilateral caudate nucleus did not differ between the bvFTD patients and the HCs (left: 0.036±0.023 vs. 0.060±0.056 ppm, p=0.128; right: 0.042±0.039 vs. 0.039±0.029 ppm, p=0.800). However, the putamina showed higher QSM values in bvFTD patients compared to HCs (left: 0.025±0.030 vs. 0.002±0.021 ppm, p=0.033; right: 0.019±0.024 vs. -0.001±0.029ppm, p=0.054). Furthermore, a negative correlation between QSM values of the left putamen and relative perfusion in the midfrontal cortex (r= -0.580, p=0.048) as well as respective trends in other frontal brain region were detected. Conclusion: Against our hypothesis, we could not find differences in QSM values of the caudate nuclei in patients with bvFTD compared to HCs. However, higher QSM values were observed in the putamina of bvFTD patients compared to HCs. These QSM values partially/negatively correlated with blood flow in the frontal cortex. These results point to a disruption of the iron homoeostasis in bvFTD potentially being associated with neuronal injury. However, the detected QSM changes were only moderate. Thus, the potential of QSM to serve as supportive (in addition to the PET readouts) bvFTD biomarker remains doubtful.