Ates Fettahoglu

All Publications

• Early-Frame [18F]Florbetaben PET/MRI for Cerebral Blood Flow Quantification in Patients with Cognitive Impairment: Comparison to an [15O]Water Gold Standard. Journal of nuclear medicine : official publication, Society of Nuclear Medicine Fettahoglu, A., Zhao, M., Khalighi, M., Vossler, H., Jovin, M., Davidzon, G., Zeineh, M., Boada, F., Mormino, E., Henderson, V. W., Moseley, M., Chen, K. T., Zaharchuk, G. 2023

  Abstract

  Cerebral blood flow (CBF) may be estimated from early-frame PET imaging of lipophilic tracers, such as amyloid agents, enabling measurement of this important biomarker in participants with dementia and memory decline. Although previous methods could map relative CBF, quantitative measurement in absolute units (mL/100 g/min) remained challenging and has not been evaluated against the gold standard method of [15O]water PET. The purpose of this study was to develop and validate a minimally invasive quantitative CBF imaging method combining early [18F]florbetaben (eFBB) with phase-contrast MRI using simultaneous PET/MRI. Methods: Twenty participants (11 men and 9 women; 8 cognitively normal, 9 with mild cognitive impairment, and 3 with dementia; 10 β-amyloid negative and 10 β-amyloid positive; 69 ± 9 y old) underwent [15O]water PET, phase-contract MRI, and eFBB imaging in a single session on a 3-T PET/MRI scanner. Quantitative CBF images were created from the first 2 min of brain activity after [18F]florbetaben injection combined with phase-contrast MRI measurement of total brain blood flow. These maps were compared with [15O]water CBF using concordance correlation (CC) and Bland-Altman statistics for gray matter, white matter, and individual regions derived from the automated anatomic labeling (AAL) atlas. Results: The 2 methods showed similar results in gray matter ([15O]water, 55.2 ± 14.7 mL/100 g/min; eFBB, 55.9 ± 14.2 mL/100 g/min; difference, 0.7 ± 2.4 mL/100 g/min; P = 0.2) and white matter ([15O]water, 21.4 ± 5.6 mL/100 g/min; eFBB, 21.2 ± 5.3 mL/100 g/min; difference, -0.2 ± 1.0 mL/100 g/min; P = 0.4). The intrasubject CC for AAL-derived regions was high (0.91 ± 0.04). Intersubject CC in different AAL-derived regions was similarly high, ranging from 0.86 for midfrontal regions to 0.98 for temporal regions. There were no significant differences in performance between the methods in the amyloid-positive and amyloid-negative groups as well as participants with different cognitive statuses. Conclusion: We conclude that eFBB PET/MRI can provide robust CBF measurements, highlighting the capability of simultaneous PET/MRI to provide measurements of both CBF and amyloid burden in a single imaging session in participants with memory disorders.

  View details for DOI 10.2967/jnumed.123.266273

  View details for PubMedID 38071587

• Short- and Long-Term MRI Assessed Hemodynamic Changes in Pediatric Moyamoya Patients After Revascularization. Journal of magnetic resonance imaging : JMRI Zhao, M. Y., Tong, E., Duarte Armindo, R., Fettahoglu, A., Choi, J., Bagley, J., Yeom, K. W., Moseley, M., Steinberg, G. K., Zaharchuk, G. 2023

  Abstract

  Cerebrovascular reserve (CVR) reflects the capacity of cerebral blood flow (CBF) to change following a vasodilation challenge. Decreased CVR is associated with a higher stroke risk in patients with cerebrovascular diseases. While revascularization can improve CVR and reduce this risk in adult patients with vasculopathy such as those with Moyamoya disease, its impact on hemodynamics in pediatric patients remains to be elucidated. Arterial spin labeling (ASL) is a quantitative MRI technique that can measure CBF, CVR, and arterial transit time (ATT) non-invasively.To investigate the short- and long-term changes in hemodynamics after bypass surgeries in patients with Moyamoya disease.Longitudinal.Forty-six patients (11 months-18 years, 28 females) with Moyamoya disease.3-T, single- and multi-delay ASL, T1-weighted, T2-FLAIR, 3D MRA.Imaging was performed 2 weeks before and 1 week and 6 months after surgical intervention. Acetazolamide was employed to induce vasodilation during the imaging procedure. CBF and ATT were measured by fitting the ASL data to the general kinetic model. CVR was computed as the percentage change in CBF. The mean CBF, ATT, and CVR values were measured in the regions affected by vasculopathy.Pre- and post-revascularization CVR, CBF, and ATT were compared for different regions of the brain. P-values <0.05 were considered statistically significant.ASL-derived CBF in flow territories affected by vasculopathy significantly increased after bypass by 41 ± 31% within a week. At 6 months, CBF significantly increased by 51 ± 34%, CVR increased by 68 ± 33%, and ATT was significantly reduced by 6.6 ± 2.9%.There may be short- and long-term improvement in the hemodynamic parameters of pediatric Moyamoya patients after bypass surgery.4 TECHNICAL EFFICACY: Stage 2.

  View details for DOI 10.1002/jmri.28902

  View details for PubMedID 37515518

• Multimodal Perfusion PET/MR Imaging with [18F]-Labeled FDG, FBB and PI-2620 within the AT(N) Framework Fettahoglu, A., Zhao, M. Y., Mormino, E., Zeineh, M., Moseley, M., Zaharchuk, G. 2023

  View details for DOI 10.1007/s10334-023-01108-9

• Determination of PET Tracer Arrival Time (TAT) in the Brain Using Early-Phase Uptake Dynamics: Conmparison to Simultaneous ASL Arterial Transit Time (ATT) Fettahoglu, A., Khalighi, M., Zhao, M. Y., Moseley, M., Zaharchuk, G. ISMRM Workshop on PET/MRI. 2023
• Eddy-current characterization and pre-emphasis on a compact inside-out nonlinear gradient ISMRM Fettahoglu, A., Zhang, H., Elsaid, N., Galiana, G. ISMRM. 2023
• Validation of early-frame [18F]FDG PET for CBF quantification: Comparison to simultaneous eASL measurements in memory patients Fettahoglu, A., Zhao, M. Y., Chen, K., Khalighi, M., Zeineh, M., Mormino, E., Moseley, M., Zaharchuk, G. AAIC. 2023
• Dual-phase PET for Cerebral Blood Flow Quantification & Amyloid Imaging Using [18F]Florbetaben: Validation Against a Gold Standard [15O]Water ISMRM Workshop on PET/MRI Fettahoglu, A., Zhao, M. Y., Khalighi, M., Mormino, E., Chen, K., Moseley, M., Zaharchuk, G. Proc. ISMRM Workshop on PET/MRI 2023. 2023
• Analysis of gas breakdown and electrostatic simulation characteristics of a Spherical Inertial Electrostatic Confinement Fusion Chamber (SIEC-K) Journal of Nuclear Sciences Fettahoglu, A. 2021

  View details for DOI 10.1501/nuclear.2023.53