Objectives Evidence suggests that while objective binge eating (OBE) and subjective binge eating (SBE) differ in the amount of food consumed, both are associated with impairment in people with eating disorders. However, only OBE is accounted for in the diagnostic criteria of eating disorders. This study compared the sociodemographic profile and burden of OBE versus SBE at a population level. Design Population-based survey. Participants A representative sample of 3028 men and women. Participants were categorised into four groups based on their reporting of binge eating in the past 3 months: non-binge eating group (no OBE or SBE), OBE group, SBE group and OSBE group (both OBE and SBE). Outcome measures Demographics (age, genderand body mass index, BMI), binge eating, distress, weight/shape overvaluation and health-related quality of life. Groups were compared on sociodemographic information, overvaluation and health-related quality of life. The OBE and SBE groups were also compared on the distress related to binge eating. Results No differences were found between the SBE group and OBE group in age, gender, BMI, mental health-related quality of life and overvaluation (all p>0.05). However, differences were found in the OSBE participants, namely that they were younger, had a higher mean BMI, lower mental health-related quality of life and higher overvaluation of weight/shape than the non-binge-eating participants (all p<0.001). Proportions of participants who reported distress related to binge eating in the OBE and SBE groups also did not differ (p=0.678). Conclusion There is little difference in the demographic profile or burden of people who engage in OBE versus SBE, supporting the proposed inclusion of SBE in the diagnostic criteria for eating disorders in International Classification of Diseases-11. People who experience both OBE and SBE may experience a relatively higher eating disorder severity and impairment.

While ultrasound (US) guidance has been used during central venous catheterization to reduce complications, including the puncturing of arteries, the rate of such problems remains non-negligible. To further reduce complication rates, mixed-reality systems have been proposed as part of the user interface for such procedures. We demonstrate the use of a surgical navigation system that renders a calibrated US image, and the needle and its trajectory, in a common frame of reference. We compare the effectiveness of this system, whereby images are rendered on a planar monitor and within a head-mounted display (HMD), to the standard-of-care US-only approach, via a phantom-based user study that recruited 31 expert clinicians and 20 medical students. These users performed needle-insertions into a phantom under the three modes of visualization. The success rates were significantly improved under HMD-guidance as compared to US-guidance, for both expert clinicians (94% vs. 70%) and medical students (70% vs. 25%). Users more consistently positioned their needle closer to the center of the vessel’s lumen under HMD-guidance compared to US-guidance. The performance of the clinicians when interacting with this monitor system was comparable to using US-only guidance, with no significant difference being observed across any metrics. The results suggest that the use of an HMD to align the clinician’s visual and motor fields promotes successful needle guidance, highlighting the importance of continued HMD-guidance research.

Near-infrared spectroscopy (NIRS) is now widely used for neuromonitoring owing to its portability, safety, and sensitivity to changes in cerebral blood oxygenation and metabolism.^{1 – 7} The technique is based on measuring the effects of light–tissue interaction, which can be used to quantify tissue optical properties, such as its absorption and scattering coefficients.⁸ In the NIR range (650 to 1100 nm), the tissue light absorbers (i.e., chromophores) of clinical importance are water, hemoglobin, lipid, and cytochrome-c-oxidase (CCO)—an enzyme involved in cellular oxidative metabolism.⁹ NIRS is highly sensitive to the oxygenation state of hemoglobin and can easily quantify changes in the concentrations of oxy- and deoxy-hemoglobin (HbO and Hb) using their distinct optical signatures.¹⁰ Although NIRS measures of blood oxygenation are commonly used as a surrogate for tissue oxygen metabolism,¹¹ the redox state of CCO is believed to be a superior biomarker as it reflects tissue oxygen metabolism at the cellular level.¹² Notably, CCO is the terminal electron acceptor in the mitochondrial electron transport chain, and its redox state is dependent on oxygen availability and electron supply.¹³ Further, hemoglobin deoxygenates readily with small reductions in oxygen tension, whereas CCO is relatively insensitive to the fluctuations that occur under normal physiological conditions.^{13 – 15} CCO reduces only under extreme hypoxic conditions;^{13 – 15} thus, it may be a better indicator of impending brain injury than blood oxygen saturation.¹²

Quantification of cytochrome-c-oxidase (CCO) can directly inform about cerebral metabolic capacity and function, but limited options currently exist for its in vivo assessment. Near-infrared spectroscopy (NIRS) has the potential to quantify CCO and its redox states, but hyperspectral absorption measurements are required due to their broad absorption profiles and low concentrations relative to hemoglobin. While this may be achieved with continuous-wave broadband NIRS (bNIRS), separating the signal contributions of absorption and scattering remains a challenge. Alternatively, time-resolved NIRS (trNIRS) can directly disentangle absorption and scattering but is typically constrained to a few wavelengths. This work aimed to develop an approach for quantifying absolute CCO concentration using discrete-wavelength trNIRS to calibrate bNIRS, yielding calibrated bNIRS (cbNIRS). Monte-Carlo simulations were conducted to validate the algorithm. Subsequently, a hybrid cbNIRS system was assembled, and tissue-mimicking phantoms were prepared with blood, Intralipid, and either yeast or sodium dithionite for validation. The simulations demonstrated that the algorithm can accurately measure absorption across the spectral range (error = 0.8 ± 0.4%). Further, the concentrations of CCO and its different redox states were estimated with an error of 7.9% or less. In the phantom experiments, the measured HbT concentration increased with the addition of blood, but not yeast nor sodium dithionite, and the value agreed with the expected concentration estimated from the packed cell volume of blood. A large increase in total CCO was measured only after the addition of yeast (1.8 ± 0.4 µM). Transitions in the oxygenation state of hemoglobin and redox state of CCO followed the expected trends as the phantom was deoxygenated and reoxygenated. Additionally, the sodium dithionite experiments confirmed that the COO signal measured with cbNIRS is not a result of crosstalk with the hemoglobin signal. This work demonstrates that absolute concentrations of both redox states of CCO can be quantified with high accuracy using cbNIRS. Future work will assess the feasibility of in vivo CCO measurements.

Near-infrared spectroscopy (NIRS) is an effective technique for noninvasive monitoring of cerebral hemodynamics, especially in neonates due to their thinner scalp and skull.^{1 – 5} To quantify tissue blood content and oxygenation with NIRS, the effects of light scattering must be separated from those of absorption. This can be achieved with continuous-wave hyperspectral NIRS (h-NIRS), which estimates the concentrations of oxy- and deoxy-hemoglobin (HbO and Hb) from light attenuation at dozens of wavelengths rather than just a discrete few. In this approach, the contribution of scattering is dampened, and absolute absorption is estimated through spectral differentiation.^{6 – 15} Moreover, h-NIRS uses simple instrumentation and computationally efficient algorithms, unlike frequency-domain and time-resolved NIRS, making it a promising approach for wider clinical adoption.^{16 – 19} Currently, most h-NIRS devices for in vivo tissue monitoring are based on custom-built spectrometers^{12,20 – 26}; however, the development of low-cost, miniature, off-the-shelf spectrometers would offer several advantages, including greater accessibility, smaller footprint, and portability for point-of-care applications.

We developed a neck central line insertion guidance system that renders 3D ultrasound (US) surface reconstructions of the carotid artery (CA) and internal jugular vein (IJV), a tracked model of the needle, and needle trajectory on a 2D monitor. Twenty clinicians evaluated this system compared to US-only guidance on a phantom using time and insertion accuracy metrics. The 3D system had a 100% success rate compared to 70% for the US-only system. The average distance from the centre line of the US reconstructed IJV was $1.8\pm 0.9$ mm under $3$D guidance compared to $4.2\pm 2.9$ mm for US-only. Our system significantly improved needle insertion success rates and targeting accuracy compared to the US-only approach through a radiation-free surface reconstruction of the neck vascular structures. This work has the potential to provide a mobile 3D imaging and visualisation system for needle-based vascular interventions.