Brain-computer interfaces (BCI) are becoming increasingly popular as a tool to improve the quality of life of patients with brain injuries. Recently, time-resolved functional near-infrared spectroscopy (TR-fNIRS) based BCIs are gaining traction because of the enhanced depth sensitivity leading to lower signal contamination from the extracerebral layers. In this study, we present the first account of TR-fNIRS based BCI for 'mental communication' on healthy participants. 21 participants were recruited and were repeatedly asked a series of questions where they were instructed to imagine playing tennis for 'yes' and to stay relaxed for 'no'. The change in the mean-time of flight of photons was used to calculate the change in concentration of oxy-and deoxyhemoglobin since it provides a good compromise between depth sensitivity and signal-to-noise ratio. Features were extracted from the average oxyhemoglobin signals to classify them as a 'yes' or 'no' responses. A lineardiscriminant analysis (LDA) and a support vector machine (SVM) classifiers were used to classify the responses using the leave-one-out cross-validation method. The overall accuracies achieved for all participants were 75% and 76%, using LDA and SVM respectively. The results also reveal that there is no significant difference in accuracy between questions. In addition, physiological parameters (heart rate and mean arterial pressure) were recorded on seven of the twenty-one participants during motor imagery and rest to investigate changes in these parameters between conditions. No significant difference in these parameters was found between conditions. To our knowledge, this is the first report of TR-fNIRS being used as a BCI on healthy controls, and our work suggests that TR-fNIRS would be suitable as a BCI for patients with brain injuries.

During cardiac surgery with cardiopulmonary bypass (CPB), adequate maintenance of cerebral blood flow (CBF) is vital in preventing postoperative neurological injury – i.e. stroke, delirium, cognitive impairment. Reductions in CBF large enough to impact cerebral energy metabolism can lead to tissue damage and subsequent brain injury. Current methods for neuromonitoring during surgery are limited. This study presents the clinical translation of a hybrid optical neuromonitor for continuous intraoperative monitoring of cerebral perfusion and metabolism in ten patients undergoing non-emergent cardiac surgery with non-pulsatile CPB. The optical system combines broadband near-infrared spectroscopy (B-NIRS) to measure changes in the oxidation state of cytochrome c oxidase (oxCCO) – a direct marker of cellular energy metabolism – and diffuse correlation spectroscopy (DCS) to provide an index of cerebral blood flow (CBFi). As the heart was arrested and the CPB-pump started, increases in CBFi (88.5 ± 125.7%) and significant decreases in oxCCO (−0.5 ± 0.2 µM) were observed; no changes were noted during transitions off CPB. Fifteen hypoperfusion events, defined as large and sustained reductions in CPB-pump flow rate, were identified across all patients and resulted in significant decreases in perfusion and metabolism when mean arterial pressure dropped to 30 mmHg or below. The maximum reduction in cerebral blood flow preceded the corresponding metabolic reduction by 18.2 ± 15.0 s. Optical neuromonitoring provides a safe and non-invasive approach for assessing intraoperative perfusion and metabolism and has potential in guiding patient management to prevent adverse clinical outcomes.

Post-hemorrhagic ventricular dilatation (PHVD) is characterized by a build-up of cerebral spinal fluid (CSF) in the ventricles, which increases intracranial pressure and compresses brain tissue. Clinical interventions (i.e., ventricular taps, VT) work to mitigate these complications through CSF drainage; however, the timing of these procedures remains imprecise. This study presents Neonatal NeuroMonitor (NNeMo), a portable optical device that combines broadband near-infrared spectroscopy (B-NIRS) and diffuse correlation spectroscopy (DCS) to provide simultaneous assessments of cerebral blood flow (CBF), tissue saturation (S_tO₂), and the oxidation state of cytochrome c oxidase (oxCCO). In this study, NNeMo was used to monitor cerebral hemodynamics and metabolism in PHVD patients selected for a VT. Across multiple VTs in four patients, no significant changes were found in any of the three parameters: CBF increased by 14.6 ± 37.6% (p = 0.09), S_tO₂ by 1.9 ± 4.9% (p = 0.2), and oxCCO by 0.4 ± 0.6 µM (p = 0.09). However, removing outliers resulted in significant, but small, increases in CBF (6.0 ± 7.7%) and oxCCO (0.1 ± 0.1 µM). The results of this study demonstrate NNeMo’s ability to provide safe, non-invasive measurements of cerebral perfusion and metabolism for neuromonitoring applications in the neonatal intensive care unit.

The human organic anion–transporting polypeptide 1b3 gene can operate as a fluorescent and photoacoustic imaging reporter gene based on its ability to selectively take up indocyanine green. Purpose To develop a photoacoustic imaging (PAI) reporter gene that has high translational potential. Previous research has shown that human organic anion–transporting polypeptide 1b3 (OATP1B3) pro...

Photoacoustic tomography (PAT) is a three-dimensional (3D) imaging modality that uses a combination of diffuse laser light and ultrasonic detectors to provide soft tissue contrast comparable to MRI, in a format and cost comparable to ultrasound, all without using ionizing radiation. Over the last two decades, PAT has been proposed for a multitude of medical and animal use cases, including for breast cancer screening,^1,2 prostate treatment guidance,^3,4 tumor margin assessment,^5,6 and small limb imaging.⁷ Unfortunately, while recent technological and application developments have been impressive, PAT has yet to reach its full potential, in large part due to the difficulty in obtaining complete data coverage.

Breast shapes are affected by gravitational loads and deformities. Measurements obtained in the standing position may not correlate well with measurements in the supine position, which is more representative of patient position during breast surgery. A dual color 3D surface imaging system capable of scanning patients in both supine and standing positions was developed to evaluate the effect of changes in body posture on breast morphology. The system was evaluated with breast phantoms to assess accuracy, then tested on ten subjects in three body postures to assess its effectiveness as a clinical tool. The accuracy of the system was within 0.4 mm on average across the model. For the human study, there was no effect of body posture on breast volumes (p value > 0.05), but we observed an effect of completeness of breast scans on body posture (p value < 0.05). Post-hoc tests showed that the supine position and the standing position with hands at the waist differed significantly (p value < 0.05). This study shows that the system can quantitatively evaluate the effect of subject postures, and thereby has the potential to be used to investigate peri-operative changes in breast morphology.