Measuring cerebrovascular reactivity with breath-hold fMRI in patients with Moyamoya angiopathy: MR perfusion based delay correction significantly improves agreement to [15O]water PET.

Abstract

Purpose: Breath-hold functional MRI (bh-fMRI) is able to quantify cerebrovascular reactivity. Vessel stenoses can lead to delayed hemodynamic responses. We aimed to investigate whether delay correction improves the quality of bh-fMRI compared to the diagnostic standard [¹⁵O]water PET.

Methods: The bh-fMRI data sets of 25 patients with Moyamoya Angiopathy were analyzed retrospectively without and with delay correction. Delay correction was calculated using time-to-peak (TTP) maps derived from dynamic susceptibility contrast (DSC) perfusion MRI. [¹⁵O]water PET maps and bh-fMRI maps without and with delay correction were presented blinded for delay correction to two neuroradiologists. The agreement between bh-fMRI without and with delay correction and [¹⁵O]water PET was independently and consensually rated on a 4-point-Likert scale (1 = poor, 2 = moderate, 3 = good, 4 = excellent) and compared with Wilcoxon signed-rank test.

Results: The agreement between bh-fMRI and [¹⁵O]water PET without delay correction was good/excellent (median = 3, modus = 4), and improved significantly after delay correction with medium effect size (median = 4, modus = 4, z = -2.121, p = 0.034, r = 0.42).

Conclusion: Delay correction improves the quality of bh-fMRI and seems to be helpful in clinical practice.