Imaging Deep Haemorrhage and Ischaemia in Preterm Infants' Heads with Time-Domain Near-Infrared Optical Tomography: Phantom Study.

Abstract

The occurrence of brain lesions in preterm infants is common and can result in lasting disabilities. To prevent these and to safeguard the brain through therapeutic measures or neuroprotective treatments, it is important to identify cerebral ischaemia/hypoxia and haemorrhage at an early stage. For this purpose, we have successfully developed a cutting-edge time-domain near-infrared optical tomography (TD-NIROT) system, which offers diagnostic imaging for neonatal brain oxygenation. Our objective is to validate the effectiveness of the TD-NIROT in detecting deep ischaemia/hypoxia and haemorrhages through phantom experiments. Spherical silicone phantoms were fabricated to replicate the head of preterm infant. To simulate the lesions, we made two head phantoms and embedded small inclusions mimicking ischaemia and haemorrhage at the depth of 30 mm. Additionally, a spherical interface was constructed to connect the spherical phantom to the imaging system, allowing us to collect time-domain data. Following the data acquisition, we proceeded with image reconstruction. Dice similarity was used as an indicator of the accuracy and similarity between the reconstructed images and the ground truth. The resulting images exhibited an accurate location of haemorrhage and detected the ischaemia with a slightly shifted position with Dice similarity of 0.47 and 0.27. Our experiment validates the capability of our TD-NIROT system in successfully detecting deep haemorrhages and ischaemia within the phantom model. The achieved results suggest a promising level of accuracy in the imaging process. These findings are encouraging to continue this work to ultimately achieve clinical application of the TD-NIROT system in diagnosing and monitoring neonatal brain injuries.