MR-tomographische Bestimmung der zerebrovaskulären Reservekapazität bei Probanden und Patienten mittels BOLD-Kontrast
Background and Purpose Stenosing vascular disease can be associated with an impaired cerebrovascular reserve capacity (CVRC), a finding that predicts ischemic events. Here we have investigated whether breath-holding (BH) paradigms may constitute an effective and robust alternative to the laborious inhalation of a fixed percentage of CO2 when measuring CVRC. Materials and Methods Using blood oxygenation level dependent functional magnetic resonance imaging (BOLD fMRI), eleven healthy subjects were examined with dynamic T2*-weighted echo planar imaging at 3 Tesla. CVRC was measured during episodes of BH for 10 s and 20 s, both after deep inspiration and after extended expiration, and compared to the reactivity following inhalation of an air mixture with 5 % CO2-content. Results 20 s BH-challenges yielded higher reactivities represented by corresponding higher BOLD signal changes when compared to 10 s ones, as did expiratory paradigms when compared to inspiratory ones. Mean signal changes ranged from 2 % (10 s BH after inspiration) to 3 % (20 s BH after expiration). The CO2-challenge yielded an about threefold higher reactivity (6 %). Conclusion The BH tasks evoked BOLD signal increases which compare favorably to published data. They were well tolerated in our normal subject population and avoided the elaborate and time-consuming experimental set-up required for the inhalation of a CO2-mixture. The measurement of CVRC using a 20 s BH paradigm is feasible when tested by BOLD fMRI at 3 Tesla and yields robust results which are qualitatively comparable to the inhalation of a defined CO2-concentration.