| Autor: |
Englund EK; Laboratory for Structural, Physiologic and Functional Imaging (LSPFI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA., Fernández-Seara MA; Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain., Rodríguez-Soto AE; Laboratory for Structural, Physiologic and Functional Imaging (LSPFI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA., Lee H; Laboratory for Structural, Physiologic and Functional Imaging (LSPFI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA., Rodgers ZB; Laboratory for Structural, Physiologic and Functional Imaging (LSPFI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA.; Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA., Vidorreta M; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA.; Siemens Healthineers, Madrid, Spain., Detre JA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA., Wehrli FW; Laboratory for Structural, Physiologic and Functional Imaging (LSPFI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA. |
| Abstrakt: |
Functional MRI (fMRI) can identify active foci in response to stimuli through BOLD signal fluctuations, which represent a complex interplay between blood flow and cerebral metabolic rate of oxygen (CMRO 2 ) changes. Calibrated fMRI can disentangle the underlying contributions, allowing quantification of the CMRO 2 response. Here, whole-brain venous oxygen saturation ( Y v ) was computed alongside ASL-measured CBF and BOLD-weighted data to derive the calibration constant, M , using the proposed Y v -based calibration. Data were collected from 10 subjects at 3T with a three-part interleaved sequence comprising background-suppressed 3D-pCASL, 2D BOLD-weighted, and single-slice dual-echo GRE (to measure Y v via susceptometry-based oximetry) acquisitions while subjects breathed normocapnic/normoxic, hyperoxic, and hypercapnic gases, and during a motor task. M was computed via Y v -based calibration from both hypercapnia and hyperoxia stimulus data, and results were compared to conventional hypercapnia or hyperoxia calibration methods. Mean M in gray matter did not significantly differ between calibration methods, ranging from 8.5 ± 2.8% (conventional hyperoxia calibration) to 11.7 ± 4.5% (Y v -based calibration in response to hyperoxia), with hypercapnia-based M values between ( p = 0.56). Relative CMRO 2 changes from finger tapping were computed from each M map. CMRO 2 increased by ∼20% in the motor cortex, and good agreement was observed between the conventional and proposed calibration methods. |
