Bedside Imaging of Intracranial Hemorrhage in the Neonate Using Light: Comparison with Ultrasound, Computed Tomography, and Magnetic Resonance Imaging

Abstract

Medical optical imaging (MOI) uses light emitted into opaque tissues to determine the interior structure. Previous reports detailed a portable time-of-flight and absorbance system emitting pulses of near infrared light into tissues and measuring the emerging light. Using this system, optical images of phantoms, whole rats, and pathologic neonatal brain specimens have been tomographically reconstructed. We have now modified the existing instrumentation into a clinically relevant headband-based system to be used for optical imaging of structure in the neonatal brain at the bedside. Eight medical optical imaging studies in the neonatal intensive care unit were performed in a blinded clinical comparison of optical images with ultrasound, computed tomography, and magnetic resonance imaging. Optical images were interpreted as correct in six of eight cases, with one error attributed to the age of the clot, and one small clot not seen. In addition, one disagreement with ultrasound, not reported as an error, was found to be the result of a mislabeled ultrasound report rather than because of an inaccurate optical scan. Optical scan correlated well with computed tomography and magnetic resonance imaging findings in one patient. We conclude that light-based imaging using a portable time-of-flight system is feasible and represents an important new noninvasive diagnostic technique, with potential for continuous monitoring of critically ill neonates at risk for intraventricular hemorrhage or stroke. Further studies are now underway to further investigate the functional imaging capabilities of this new diagnostic tool.

Infrared imaging of subcutaneous veins

“…Despite a long history of medical IR photography, this technique is not widely used in medicine because of time considerations [3][4][5][6][7][8][9][10]. Prior experiments provided some interesting data using other near-IR detectors [11][12][13][14][15][16][17][18][19][20][28][29][30][31]. However, the device parameters were empirically selected without detailed experimental studies leaving the clinical prospects unclear.…”

Retinotopic mapping of adult human visual cortex with high-density diffuse optical tomography

“…However, due to the large range in measured light levels, this approach places very stringent requirements on dynamic range and channel cross-talk. Despite these challenges, initial reports on DOT of the human brain demonstrate the feasibility of detecting lateralization of motor cortex activation (24,27,34), cerebral hemorrhage, decreased brain oxygenation in neonates after acute stroke (35), and vascular responsivity during the Valsalva maneuver (36). The breadth of these applications highlights the promise of the tomographic approach to optical neuroimaging.…”

Optical tomography of the neonatal brain

“…Scans performed on infants at a variety of gestational ages successfully identified intracranial hemorrhage [30,34] and focal regions of low oxygenation after acute stroke [29]. Figure 3 shows an image obtained on an infant with large bilateral intraventricular hemorrhages (confirmed by ultrasound), which clearly indicates the lesions.…”

“…Figure 3 shows an image obtained on an infant with large bilateral intraventricular hemorrhages (confirmed by ultrasound), which clearly indicates the lesions. The grayscale is proportional to the total optical absorbance at 785 nm [34]. A major drawback is the prolonged scan times (up to several hours), which is a consequence of the low source power (100 μW average) and the use of a single electronic detector.…”