Digital Rectal Exams Are Infrequently Performed Prior to Anorectal Manometry.

BACKGROUND: Digital rectal examination should be performed prior to anorectal manometry; however, real-world data is lacking. AIMS: Characterize real world rates of digital rectal and their sensitivity for detecting dyssynergia compared to anorectal manometry and balloon expulsion test. METHODS: A retrospective single-center study was conducted to examine all patients who underwent anorectal manometry for chronic constipation between 2021 and 2022 at one tertiary center with motility expertise. Primary outcomes consisted of the rate of digital rectal exam prior to anorectal manometry; and secondary outcomes included the sensitivity of digital rectal exam for dyssynergic defecation. RESULTS: Only 42.3% of 142 patients had digital rectal examinations prior to anorectal manometry. Overall sensitivity for detecting dyssynergic defecation was 46.4%, but significantly higher for gastroenterology providers (p = .004), and highest for gastroenterology attendings (82.6%). CONCLUSIONS: Digital rectal examination is infrequently performed when indicated for chronic constipation. Sensitivity for detecting dyssynergic defecation may be impacted by discipline and level of training.

Mitral valve surgery after failed transcatheter edge-to-edge repair: a review and word of caution.

PURPOSE OF REVIEW: As transcatheter edge-to-edge mitral valve repair (TEER) evolves and indications broaden to include younger and lower surgical risk patients, it is essential to understand TEER failure trends and potential impact on subsequent mitral valve surgery, especially when pertaining to feasibility of durable valve reconstruction as opposed to de-novo repair. RECENT FINDINGS: Results of the two largest series analysing mitral valve surgery following TEER have demonstrated remarkably low repairability rates with consequent need for valve replacement. Post TEER surgery was associated with high early and late mortalities, likely as a reflection of patient baseline characteristics and acuity of surgery. Presence and correction of concomitant cardiac pathologies were a frequent finding. Centre and surgeon volumes were important factors in optimizing the likelihood of salvage repair and reducing perioperative risks. SUMMARY: Surgical mitral valve repair in reference centres remain the gold standard and the most durable treatment for degenerative mitral disease with excellent perioperative safety outcomes. Given the high likelihood of needing high-risk mitral valve replacement when TEER fails, consideration for potentially less durable transcatheter alternatives should be taken with caution in younger or lower surgical risk patients.

Fast pulse shaping for a novel gated electron mirror.

We present the design and prototype of a switchable electron mirror, along with a technique for driving it with an arbitrary pulse shape. We employ a general technique for electronic pulse-shaping, where high fidelity of the pulse shape is required, but the characteristics of the system, which are possibly nonlinear, are not known. This driving technique uses an arbitrary waveform generator to pre-compensate the pulse, with a simple iterative algorithm used to generate the input waveform. This is a broadly applicable, general method for arbitrary pulse shaping. Driving our switchable electron mirror with a flat-top pulse, we demonstrate an improvement in rms error of roughly two orders of magnitude compared to an uncompensated waveform. Our results demonstrate the feasibility of high fidelity waveform reproduction in the presence of nonidealities, with immediate applications in the realization of novel electron optical components.

Design for a 10 keV multi-pass transmission electron microscope.

Multi-pass transmission electron microscopy (MPTEM) has been proposed as a way to reduce damage to radiation-sensitive materials. For the field of cryo-electron microscopy (cryo-EM), this would significantly reduce the number of projections needed to create a 3D model and would allow the imaging of lower-contrast, more heterogeneous samples. We have designed a 10 keV proof-of-concept MPTEM. The column features fast-switching gated electron mirrors which cause each electron to interrogate the sample multiple times. A linear approximation for the multi-pass contrast transfer function (CTF) is developed to explain how the resolution depends on the number of passes through the sample.

Quantum correlation enhanced super-resolution localization microscopy enabled by a fibre bundle camera.

Despite advances in low-light-level detection, single-photon methods such as photon correlation have rarely been used in the context of imaging. The few demonstrations, for example of subdiffraction-limited imaging utilizing quantum statistics of photons, have remained in the realm of proof-of-principle demonstrations. This is primarily due to a combination of low values of fill factors, quantum efficiencies, frame rates and signal-to-noise characteristic of most available single-photon sensitive imaging detectors. Here we describe an imaging device based on a fibre bundle coupled to single-photon avalanche detectors that combines a large fill factor, a high quantum efficiency, a low noise and scalable architecture. Our device enables localization-based super-resolution microscopy in a non-sparse non-stationary scene, utilizing information on the number of active emitters, as gathered from non-classical photon statistics.

Supersensitive polarization microscopy using NOON states of light.

A quantum polarized light microscope using entangled NOON states with N=2 and N=3 is shown to provide phase supersensitivity beyond the standard quantum limit. We constructed such a microscope and imaged birefringent objects at a very low light level of 50 photons per pixel, where shot noise seriously hampers classical imaging. The NOON light source is formed by combining a coherent state with parametric down-converted light. We were able to show improved phase images with sensitivity close to the Heisenberg limit.

Sub-Rayleigh lithography using high flux loss-resistant entangled states of light.

Quantum lithography achieves phase superresolution using fragile, experimentally challenging entangled states of light. We propose a scalable scheme for creating features narrower than classically achievable with reduced use of quantum resources and, consequently, enhanced resistance to loss. The scheme is an implementation of interferometric lithography using a mixture of a spontaneous parametric down-converted entangled state with intense classical coherent light. We measure coincidences of up to four photons mimicking multiphoton absorption. The results show a narrowing of the interference fringes of up to 30% with respect to the best analogous classical scheme using only 10% of the nonclassical light required for creating NOON states.