CIRM: high-resolution T1w and dual-echo pCASL in coronary artery disease and controls

Dual-echo pseudo-continuous arterial spin labeling (pCASL) acquired during a prospectively targeted respiratory gas challenge, with an anatomical T1w and a separate M0 calibration image, in older adults with coronary artery disease (CAD) and age- and sex-matched healthy controls. The dual-echo readout yields perfusion and BOLD signals from the same acquisition, so cerebrovascular reactivity can be estimated in both CBF and BOLD units from a single breathing manipulation. Participants ------------ 84 participants aged 51-84 (mean 66.8): 46 CAD and 38 controls, 66 male and 18 female. Age, sex, and diagnostic group are in participants.tsv. Ages over 89 would be reported as "89+"; none occur here. Contents -------- sub-<label>/anat/ T1w anatomical reference sub-<label>/perf/ echo-1 asl perfusion-weighted (short TE) echo-2 asl BOLD-weighted (long TE) m0scan calibration, 3 repeats, TR 10 s aslcontext.tsv control/label order per volume recording-gas physio end-tidal PCO2 and PO2 sourcedata/respiract/ raw RespirAct exports 82 participants have both echoes; one has only the long-TE echo, which was the only one reconstructed at the scanner. 83 have an aslcontext.tsv. 64 have gas traces; the remainder either did not tolerate the hypercapnia challenge or the RespirAct record does not cover the imaging run. Acquisition ----------- 3 T Siemens MAGNETOM Skyra, 32-channel head coil. pCASL: 2D EPI, 12 slices, 3.4375 x 3.4375 x 7.0 mm, 15% slice gap, TR 4000 ms, TE 10 / 30 ms, flip 90 deg, GRAPPA 2, labeling offset 80 mm, no background suppression, no vascular crushing. Labeling duration 1517 ms. Post-labeling delay 1800 ms in the earliest protocol and 1300 ms thereafter; the value used is recorded per file in PostLabelingDelay, with PostLabelingDelaySource noting its origin. M0: identical geometry, TR 10 s for full magnetization recovery, 3 repeats. T1w: MPRAGE. Most participants have a 0.9 mm isotropic scan; the remainder have 1.5 mm, which was the highest resolution acquired for them. A low-resolution T1w was also collected with the gas mask in place to aid pCASL slab registration, and is not included here. Gas challenge: three conditions were targeted for 2 min each, preceded and followed by 2 min of air -- hypercapnia (+5 mmHg end-tidal PCO2), isocapnic hyperoxia (150 mmHg end-tidal PO2), and the two combined. Run length varies with protocol: most series are 210 volumes (840 s) or 227 volumes (891 s). Shorter series are participants who received only the 5-minute resting-perfusion scan because they could not tolerate hypercapnia, plus a small number of runs stopped early. Acquisition parameters come from the scanner protocol and from the published methods (https://doi.org/10.1007/s11357-026-02128-8). Echo times, repetition times, and slice timing are taken from each series' own DICOM-derived sidecar rather than assumed, since the protocol changed over the study. Processing applied ------------------ Images are otherwise unprocessed. Two things were done: Skull stripping, with FreeSurfer mri_synthstrip. The T1w and M0 were stripped directly. mri_synthstrip accepts single-frame input only, so the 4D pCASL series were masked with the brain mask derived from the M0 of the same session; where M0 and pCASL geometry disagreed, the mask came from the pCASL series' own temporal mean instead. Gas traces resampled to 1 Hz. RespirAct records end-tidal values once per breath, at a median interval of 3.8 s across this cohort, so the series is irregular. It was linearly interpolated onto a regular 1 Hz grid; gaps wider than 20 s are left as n/a rather than interpolated across. StartTime is relative to the SequenceStart event in the RespirAct log, which shares a clock with the end-tidal samples, and is negative because recording begins during the preparation phase before the imaging run. The raw exports are in sourcedata/. Reference --------- Sanami S, et al. Cardiorespiratory fitness in relation to cerebral vascular and metabolic health in older adults with coronary artery disease. GeroScience. https://doi.org/10.1007/s11357-026-02128-8