Estimation of regional cerebral blood flow distribution in infants by multichannel near-infrared spectroscopy with indocyanine green

This is the report on the use of multichannel near-infrared spectroscopy (MNIRS) with indocyanine green (ICG) to determine regional cerebral blood flow (rCBF) distribution disturbance in infants. We measured rCBF in an infant with subdural hemorrhage after surgical removal of a subdural hematoma. A probe consisting of 12 optical fibers, 6 for transmission and 6 for detection, was set on the right and then left temporal regions of the head of the infant, and 16 measuring points were determined. Changes in ICG concentration were recorded using MNIRS (Near infrared optical imaging system, OMM-2000, Shimadzu Corp., Japan). The light sources were three continuous laser diodes with wavelengths of 776, 804 and 828 nm. The rCBF was imaged on the basis of integrated signals during a specified interval after the first rapid rise in ICG response. Simultaneously, the arterial blood concentration of ICG was noninvasively measured by pulse dye densitometry using the general principles of pulse oximetry. rCBF was calculated from the modified Fick equation. It was found that rCBF in the area of intracerebral involvement was less than that in the contralateral hemisphere, as was also found by single photon emission computed tomography. We conclude that our method is useful for measuring rCBF distribution at the bedside in neonates with an illness in the acute phase.