Hypercapnic BOLD MRI compared to H$_{2}$$^{15}$O PET/CT for the hemodynamic evaluation of patients with Moyamoya Disease

Abstract

BACKGROUND AND PURPOSE

Patients with Moyamoya Disease (MMD) need hemodynamic evaluation of vascular territories at risk of stroke. Today's investigative standards include H$_{2}$$^{15}$O PET/CT with pharmacological challenges with acetazolamide (ACZ). Recent developments suggest that CO$_{2}$-triggered blood‑oxygen-level-dependent (BOLD) functional MRI might provide comparable results to current standard methods for evaluation of territorial hemodynamics, while being a more widely available and easily implementable method. This study examines results of a newly developed quantifiable analysis algorithm for CO$_{2}$-triggered BOLD MRI in Moyamoya patients and correlates the results with H$_{2}$$^{15}$O PET/CT with ACZ challenge to assess comparability between both modalities.

METHODS

CO$_{2}$-triggered BOLD MRI was performed and compared to H$_{2}$$^{15}$O PET/CT with ACZ challenge in patients with angiographically proven MMD. Images of both modalities were analyzed retrospectively in a blinded, standardized fashion by visual inspection, as well as with a semi-quantitative analysis using stimuli-induced approximated regional perfusion-weighted data and BOLD-signal changes with reference to cerebellum.

RESULTS

20 consecutive patients fulfilled the inclusion criteria, a total of 160 vascular territories were analyzed retrospectively. Visual analysis (4-step visual rating system) of standardized, color-coded cerebrovascular reserve/reactivity maps showed a very strong correlation (Spearman's rho = 0.9, P < 0.001) between both modalities. Likewise, comparison of approximated regional perfusion changes across vascular territories (normalized to cerebellar change) reveal a highly significant correlation between both methods (Pearson's r = 0.71, P < 0.001).

CONCLUSIONS

The present analysis indicates that CO$_{2}$-triggered BOLD MRI is a very promising tool for the hemodynamic evaluation of MMD patients with results comparable to those seen in H$_{2}$$^{15}$O PET/CT with ACZ challenge. It therefore holds future potential in becoming a routine examination in the pre- and postoperative evaluation of MMD patients after further prospective evaluation.