A systematic scoping review moral distress amongst medical students.

BACKGROUND: Characterised by feelings of helplessness in the face of clinical, organization and societal demands, medical students are especially prone to moral distress (MD). Despite risks of disillusionment and burnout, efforts to support them have been limited by a dearth of data and understanding of MD in medical students. Yet, new data on how healthcare professionals confront difficult care situations suggest that MD could be better understood through the lens of the Ring Theory of Personhood (RToP). A systematic scoping review (SSR) guided by the RToP is proposed to evaluate the present understanding of MD amongst medical students. METHODS: The Systematic Evidence-Based Approach (SEBA) is adopted to map prevailing accounts of MD in medical students. To enhance the transparency and reproducibility, the SEBA methodology employs a structured search approach, concurrent and independent thematic analysis and directed content analysis (Split Approach), the Jigsaw Perspective that combines complementary themes and categories, and the Funnelling Process that compares the results of the Jigsaw Perspective with tabulated summaries to ensure the accountability of these findings. The domains created guide the discussion. RESULTS: Two thousand six hundred seventy-one abstracts were identified from eight databases, 316 articles were reviewed, and 20 articles were included. The four domains identified include definitions, sources, recognition and, interventions for MD. CONCLUSIONS: MD in medical students may be explained as conflicts between the values, duties, and principles contained within the different aspects of their identity. These conflicts which are characterised as disharmony (within) and dyssynchrony (between) the rings of RToP underline the need for personalised and longitudinal evaluations and support of medical students throughout their training. This longitudinal oversight and support should be supported by the host organization that must also ensure access to trained faculty, a nurturing and safe environment for medical students to facilitate speak-up culture, anonymous reporting, feedback opportunities and supplementing positive role modelling and mentoring within the training program.

Sparsity-based reconstruction for super-resolved limited-view photoacoustic computed tomography deep in a scattering medium.

Delay-and-sum beamforming (DSB) of photoacoustic data does not incorporate a priori spatial sparsity of the imaging target. By incorporating this information into beamforming for limited-view photoacoustic computed tomography, we experimentally obtained enhanced resolution images of wires at a depth of 8.5 mm in a tissue mimicking scattering medium. Using a 21 MHz transducer, we improved the resolution from the 200 to 250 µm achieved by DSB to 75 µm. The sparsity-based technique also generated a cleaner image with a background signal level of roughly -50 dB, much lower than the roughly -18 dB background signal level of DSB.

3D photoacoustic imaging using Hadamard-bias encoding with a crossed electrode relaxor array.

A novel 3D photoacoustic imaging technique is experimentally demonstrated using a 64×64 element bias-sensitive crossed-electrode relaxor array. This technique allows for large 2D arrays to receive across all elements while using minimal channel counts. Hadamard-bias patterns are applied to column electrodes while signals are measured from row electrodes. Photoacoustic signals are measured from a crossed-wire phantom in an intralipid scattering medium. The Hadamard-bias-encoded imaging scheme showed a signal-to-noise (SNR) of 25.3 dB, while the single-column biasing strategy (or identity-matrix-bias pattern) showed a SNR of 8.8 dB.

The retrocaval ureter - A rare developmental cause for urinary tract obstruction.

Retrocaval ureter is a rare congenital anomaly with few reported cases worldwide. In this case report, we describe a clinical presentation that demonstrates the stereotypical imaging features of a retrocaval ureter on ultrasound, computed tomography and nuclear imaging studies in a 38-year-old male patient who fits the classic reported patient demographics.

Vascular compression syndromes in the abdomen and pelvis: a concise pictorial review.

Vascular compression syndromes are a diverse group of pathologies that can manifest asymptomatically and incidentally in otherwise healthy individuals or symptomatically with a spectrum of presentations. Due to their relative rarity, these syndromes are often poorly understood and overlooked. Early identification of these syndromes can have a significant impact on subsequent clinical management. This pictorial review provides a concise summary of seven vascular compression syndromes within the abdomen and pelvis including median arcuate ligament (MAL) syndrome, superior mesenteric artery (SMA) syndrome, nutcracker syndrome (NCS), May-Thurner syndrome (MTS), ureteropelvic junction obstruction (UPJO), vascular compression of the ureter, and portal biliopathy. The demographics, pathophysiology, predisposing factors, and expected treatment for each compression syndrome are reviewed. Salient imaging features of each entity are illustrated through imaging examples using multiple modalities including ultrasound, fluoroscopy, CT, and MRI.

Left Ventricular Ejection Fraction Association with Acute Ischemic Stroke Outcomes in Patients Undergoing Thrombolysis.

(1) Background: Little is known about how left ventricular systolic dysfunction (LVSD) affects functional and clinical outcomes in acute ischemic stroke (AIS) patients undergoing thrombolysis; (2) Methods: A retrospective observational study conducted between 2006 and 2018 included 937 consecutive AIS patients undergoing thrombolysis. LVSD was defined as left ventricular ejection fraction (LVEF) < 50%. Univariate and multivariate binary logistic regression analysis was performed for demographic characteristics. Ordinal shift regression was used for functional modified Rankin Scale (mRS) outcome at 3 months. Survival analysis of mortality, heart failure (HF) admission, myocardial infarction (MI) and stroke/transient ischemic attack (TIA) was evaluated with a Cox-proportional hazards model; (3) Results: LVSD patients in comparison with LVEF ≥ 50% patients accounted for 190 and 747 patients, respectively. LVSD patients had more comorbidities including diabetes mellitus (100 (52.6%) vs. 280 (37.5%), p < 0.001), atrial fibrillation (69 (36.3%) vs. 212 (28.4%), p = 0.033), ischemic heart disease (130 (68.4%) vs. 145 (19.4%), p < 0.001) and HF (150 (78.9%) vs. 46 (6.2%), p < 0.001). LVSD was associated with worse functional mRS outcomes at 3 months (adjusted OR 1.41, 95% CI 1.03-1.92, p = 0.030). Survival analysis identified LVSD to significantly predict all-cause mortality (adjusted HR [aHR] 3.38, 95% CI 1.74-6.54, p < 0.001), subsequent HF admission (aHR 4.23, 95% CI 2.17-8.26, p < 0.001) and MI (aHR 2.49, 95% CI 1.44-4.32, p = 0.001). LVSD did not predict recurrent stroke/TIA (aHR 1.15, 95% CI 0.77-1.72, p = 0.496); (4) Conclusions: LVSD in AIS patients undergoing thrombolysis was associated with increased all-cause mortality, subsequent HF admission, subsequent MI and poorer functional outcomes, highlighting a need to optimize LVEF.

Mechanical Unloading of Engineered Human Meniscus Models Under Simulated Microgravity: A Transcriptomic Study.

Osteoarthritis (OA) primarily affects mechanical load-bearing joints, with the knee being the most common. The prevalence, burden and severity of knee osteoarthritis (KOA) are disproportionately higher in females, but hormonal differences alone do not explain the disproportionate incidence of KOA in females. Mechanical unloading by spaceflight microgravity has been implicated in OA development in cartilaginous tissues. However, the mechanisms and sex-dependent differences in OA-like development are not well explored. In this study, engineered meniscus constructs were generated from healthy human meniscus fibrochondrocytes (MFC) seeded onto type I collagen scaffolds and cultured under normal gravity and simulated microgravity conditions. We report the whole-genome sequences of constructs from 4 female and 4 male donors, along with the evaluation of their phenotypic characteristics. The collected data could be used as valuable resources to further explore the mechanism of KOA development in response to mechanical unloading, and to investigate the molecular basis of the observed sex differences in KOA.

Systematic scoping review on moral distress among physicians.

BACKGROUND: Concepts of moral distress (MD) among physicians have evolved and extend beyond the notion of psychological distress caused by being in a situation in which one is constrained from acting on what one knows to be right. With many accounts involving complex personal, professional, legal, ethical and moral issues, we propose a review of current understanding of MD among physicians. METHODS: A systematic evidence-based approach guided systematic scoping review is proposed to map the current concepts of MD among physicians published in PubMed, Embase, PsycINFO, Web of Science, SCOPUS, ERIC and Google Scholar databases. Concurrent and independent thematic and direct content analysis (split approach) was conducted on included articles to enhance the reliability and transparency of the process. The themes and categories identified were combined using the jigsaw perspective to create domains that form the framework of the discussion that follows. RESULTS: A total of 30 156 abstracts were identified, 2473 full-text articles were reviewed and 128 articles were included. The five domains identified were as follows: (1) current concepts, (2) risk factors, (3) impact, (4) tools and (5) interventions. CONCLUSIONS: Initial reviews suggest that MD involves conflicts within a physician's personal beliefs, values and principles (personal constructs) caused by personal, ethical, moral, contextual, professional and sociocultural factors. How these experiences are processed and reflected on and then integrated into the physician's personal constructs impacts their self-concepts of personhood and identity and can result in MD. The ring theory of personhood facilitates an appreciation of how new experiences create dissonance and resonance within personal constructs. These insights allow the forwarding of a new broader concept of MD and a personalised approach to assessing and treating MD. While further studies are required to test these findings, they offer a personalised means of supporting a physician's MD and preventing burn-out.

In vivo photoacoustic difference-spectra imaging of bacteria using photoswitchable chromoproteins.

Photoacoustic (PA) imaging offers great promise for deep molecular imaging of optical reporters but has difficulties in imaging multiple molecular probes simultaneously in a strong blood background. Photoswitchable chromoproteins like BphP1 have recently allowed for sensitive PA detection by reducing high-blood background signals but lack multiplexing capabilities. We propose a method known as difference-spectra demixing for multiplexing multiple photoswitchable chromoproteins and introduce a second photoswitchable chromoprotein, sGPC2. sGPC2 has a far-red and orange state with peaks at 700 and 630 nm, respectively. It is roughly one-tenth the size of BphP1 and photoswitches four times as fast (2.4% per mJ / cm2). We simultaneously image Escherichia coli expressing sGPC2 and BphP1 injected in mice in vivo. Difference-spectra demixing obtained successful multiplexed images of photoswitchable molecular probes, resulting in a 21.6-fold increase in contrast-to-noise ratio in vivo over traditional PA imaging and an 8% to 40% reduction in erroneously demixed signals in comparison with traditional spectral demixing. PA imaging and characterization were conducted using a custom-built photoswitching PA imaging system.

Multifrequency Interlaced CMUTs for Photoacoustic Imaging.

Multifrequency capacitive micromachined ultrasound transducers (CMUTs) are introduced consisting of interlaced 82- [Formula: see text] (low frequency) and 36- [Formula: see text] (high frequency) membranes. The membranes have been interlaced on a scale smaller than the shortest wavelength of operation allowing several advantages over other multifrequency transducer designs including aligned beam profiles, optimal imaging resolution, and minimal grating lobes. The low- and high-frequency CMUTs operate at 1.74 and 5.04 MHz in immersion, respectively. Multifrequency transducers have applications in wideband photoacoustic (PA) imaging where multifrequency transducers are better able to detect both high- and low-frequency PA frequency content. The PA frequency content is target size dependent, which means traditional high-frequency transducers have less sensitivity to larger objects such as diffuse contrast agents. We demonstrate that the low-frequency subarrays are able to better visualize diffuse agent distributions, while the high-frequency subarrays offer fine-resolution imaging important for microvascular imaging and structural navigation. Spectroscopically unmixed images superimpose high sensitivity images of agent concentrations (acquired using low-frequency subarrays) onto high-resolution images of microvessel-mimicking phantoms (acquired using high-frequency subarrays).

Feasibility of modulation-encoded TOBE CMUTS for real-time 3-D imaging.

Modulation-encoded top orthogonal to bottom electrode (TOBE) capacitive micromachined ultrasound transducers (CMUTs) are proposed 2-D ultrasound transducer arrays that could allow 3-D images to be acquired in a single acquisition using only N channels for an N × N array. In the proposed modulation-encoding scheme, columns are not only biased, but also modulated with a different frequency for each column. The modulation frequencies are higher than the passband of the CMUT membranes and mix nonlinearly in CMUT cells with acoustic signals to produce acoustic signal sidebands around the modulation carriers in the frequency domain. Thus, signals from elements along a row may be read out simultaneously via frequency-domain multiplexing. We present the theory and feasibility data behind modulation-encoded TOBE CMUTs. We also present experiments showing necessary modifications to the current TOBE design that would allow for crosstalk-mitigated modulation-encoding.

Top orthogonal to bottom electrode (TOBE) 2-D CMUT arrays for 3-D photoacoustic imaging.

Top orthogonal to bottom electrode (TOBE) capacitive micromachined ultrasound transducers (CMUTs) are a new transducer architecture that permits large 2-D arrays to be addressed using row-column addressing. Here, we demonstrate the feasibility of 3-D photoacoustic imaging using N laser pulses and N receive channels. We used a synthetic aperture approach to simulate a large 2 X 2 cm array using a smaller die. A hair phantom in an oil immersion medium was excited by a laser, and the received signal was dynamically focused to obtain high-resolution images. We found the TOBE CMUT to have a center frequency of 3.7 MHz with a bandwidth of 3.9 MHz. Lateral and axial resolutions were 866 ¿m and 296 µm, respectively.

Mosaic acquisition and processing for optical-resolution photoacoustic microscopy.

In optical-resolution photo-acoustic microscopy (OR-PAM), data acquisition time is limited by both laser pulse repetition rate (PRR) and scanning speed. Optical-scanning offers high speed, but limited, field of view determined by ultrasound transducer sensitivity. In this paper, we propose a hybrid optical and mechanical-scanning OR-PAM system with mosaic data acquisition and processing. The system employs fast-scanning mirrors and a diode-pumped, nanosecond-pulsed, Ytterbium-doped, 532-nm fiber laser with PRR up to 600 kHz. Data from a sequence of image mosaic patches is acquired systematically, at predetermined mechanical scanning locations, with optical scanning. After all imaging locations are covered, a large panoramic scene is generated by stitching the mosaic patches together. Our proposed system is proven to be at least 20 times faster than previous reported OR-PAM systems.