Can cerebral blood volume be measured reproducibly with an improved near infrared spectroscopy system?

In some circumstances, cerebral blood volume (CBV) can be used as a measure for cerebral blood flow. A new near infrared spectroscope was used for determining the reproducibility of CBV measurements assessed by the O-2-method. Twenty-seven healthy subjects were investigated. An intrasubject coefficient of variation (CV) was calculated. based on four identical episodes of desaturation-resaturation (O-2- method) procedures for CBV measurements. Two trials were performed, with (trial 1) and without (trial 2) disconnecting the equipment. A mean CV of 12.6% and 10.0% was found in trial I and 2. respectively. Cerebral blood volume values yield 3.60 +/- 0.82 mL 100 g(-1). Cerebral blood volume could be measured reproducible in adults using near infrared spectroscopy, if the arterial desaturation is limited to approximately 5% from baseline level.