Comparison between multiparametric arterial spin labeling and [15O]H2O positron emission tomography in patients with moyamoya disease.

Purpose: Multiparametric arterial spin labeling (MP-ASL) using delays alternating with nutation for tailored excitation (DANTE) pulse (MP-ASL_DANTE) can noninvasively quantify arterial cerebral blood volume (CBV_a) and the residence time of labeled spins in the microvascular compartment (ΔTT). We hypothesized that MP-ASL_DANTE could identify the early stages of hemodynamic impairment in patients with moyamoya disease (MMD) by detecting autoregulatory vasodilation, specifically the elevation of CBV_a. However, the clinical relevance of MP-ASL_DANTE has not yet been fully evaluated. Therefore, we compared MP-ASL_DANTE with [¹⁵O]H₂O positron emission tomography (PET) to assess its clinical relevance in patients with MMD.

Methods: MP-ASL_DANTE was performed on 11 patients, and the parameters were estimated using simulation-based deep neural networks. Furthermore, cerebrovascular reactivity (CVR) was calculated from the cerebral blood flow (CBF) before and after acetazolamide challenge using [¹⁵O]H₂O PET. Spearman's correlation analyses and group comparisons were performed.

Results: Although CBV_a (ρ = 0.0288; p = 0.6876) did not significantly correlate with PET-CVR, ΔTT showed a significant correlation with PET-CVR (ρ = -0.2599; p = 0.0002). Moreover, CBV_a could not differentiate between the normal and reduced CVR groups, regardless of the CBF conditions. However, within the normal CBF group, the reduced CVR group exhibited a significantly longer ΔTT than the normal CVR group (p = 0.0069), suggesting its capability to differentiate CVR conditions even under normal CBF conditions.

Conclusion: The comprehensive use of MP-ASL_DANTE parameters enables a detailed noninvasive evaluation of cerebral hemodynamics in patients with MMD and potentially allows for the detection of early stages of hemodynamic impairment in these patients.