3D reconstruction

Studying the detailed biomechanics of flying animals requires accurate three-dimensional coordinates for key anatomical landmarks. Traditionally, this relies on manually digitizing animal videos, a labor-intensive task that scales poorly with increasing framerates and numbers of cameras. Here, we present a workflow that combines deep learning-powered automatic digitization with filtering and correction of mislabeled points using quality metrics from deep learning and 3D reconstruction. We tested our workflow using a particularly challenging scenario: bat flight...

PURPOSE: Surface reconstructions from laryngoscopic videos have the potential to assist clinicians in diagnosing, quantifying, and monitoring airway diseases using minimally invasive techniques. However, tissue movements and deformations make these reconstructions challenging using conventional pipelines. METHODS: To facilitate such reconstructions, we developed video frame pre-filtering and featureless dense matching steps to enhance the Alicevision Meshroom SfM pipeline...

PURPOSE OF REVIEW: In the ever-evolving field of medical imaging, this review highlights significant advancements in preoperative and postoperative imaging for Tetralogy of Fallot (TOF) and double outlet right ventricle (DORV) over the past 18 months. RECENT FINDINGS: This review showcases innovations in echocardiography such as 3D speckle tracking echocardiography (3DSTE) for assessing right ventricle-pulmonary artery coupling (RVPAC) and Doppler velocity reconstruction (DoVeR) for intracardiac flow fields evaluation...

The current use of intracorporeal left ventricular assist devices in children is still limited by small body dimensions. Many children weighing of less than 30 kg requiring durable mechanical circulatory support are implanted with the Berlin Heart EXCOR, a paracorporeal device. We present the case of a girl aged 10 years with a body surface area of 1.01 m2 undergoing a safe and effective HeartMate3 implantation despite extremely small thoracic dimensions. Using computed tomography-derived three-dimensional (3D) reconstruction, it was possible to simulate several device positions finding the best HeartMate3 lodging...

AIM: To improve the results of treatment of patients with urolithiasis who underwent endoscopic interventions using a ureteral access sheath (UAS) by developing a predictive model of ureteral dilatation without pre-stenting. MATERIALS AND METHODS: A total of 180 patients with kidney stones up to 20 mm were included in the study. They were divided into two groups: in the group 1 (n=79) UAS of 12/14 Ch was used, while in group II (n=101) UAS of 10/12 Ch was inserted...

PURPOSE: MRI using 3D stack-of-spirals (SoS) readout on a high-performance gradient system is subject to strong second-order, spatially varying concomitant fields, which can lead to signal dropout and blurring artifacts that become more significant at locations farther from the gradient isocenter. A method for compensating for second-order concomitant fields in 3D axial SoS image reconstruction is described. METHODS: We retrospectively correct for second-order concomitant field-induced phase error in the 3D SoS data by slice-dependent k-space phase compensation based on the nominal spiral readout trajectories...

BACKGROUND: Large field of view CZT SPECT cameras with a ring geometry are available for some years now. Thanks to their good sensitivity and high temporal resolution, general dynamic SPECT imaging may be performed more easily, without resorting to dedicated systems. To evaluate the dynamic SPECT imaging by such cameras, we have performed an in vivo pilot study to analyze the kidney function of a pig and compare the results to standard dynamic planar imaging by a conventional gamma camera...

Uterine myomas are the most common pelvic tumors in women, which can lead to abnormal uterine bleeding, abdominal pain, pelvic compression symptoms, infertility, or adverse pregnancy. In this article, we provide a dataset named uterine myoma MRI dataset (UMD), which can be used for clinical research on uterine myoma imaging. The UMD is the largest publicly available uterine MRI dataset to date including 300 cases of uterine myoma T2-weighted imaging (T2WI) sagittal patient images and their corresponding annotation files...

AIM: To compare the image quality of virtual noncontrast (VNC) and true noncontrast (TNC) CT images and to evaluate the clinical feasibility of VNC CT images for assessing osteochondral lesions of the talus (OLTs). MATERIALS AND METHODS: Forty-five OLT patients who underwent ankle CT arthrography (CTA) using dual-layer spectral detector CT were enrolled. Reconstruction of VNC and three-dimensional volume rendering images was performed. Afterward, image noise, the signal-to-noise ratio (SNR), and the contrast-to-noise ratio (CNR) were measured...

Surface reconstruction for point clouds is an important task in 3D computer vision. Most of the latest methods resolve this problem by learning signed distance functions from point clouds, which are limited to reconstructing closed surfaces. Some other methods tried to represent open surfaces using unsigned distance functions (UDF) which are learned from ground truth distances. However, the learned UDF is hard to provide smooth distance fields due to the discontinuous character of point clouds. In this paper, we propose CAP-UDF, a novel method to learn consistency-aware UDF from raw point clouds...

Geometric Deep Learning has recently made striking progress with the advent of continuous deep implicit fields. They allow for detailed modeling of watertight surfaces of arbitrary topology while not relying on a 3D Euclidean grid, resulting in a learnable parameterization that is unlimited in resolution. Unfortunately, these methods are often unsuitable for applications that require an explicit mesh-based surface representation because converting an implicit field to such a representation relies on the Marching Cubes algorithm, which cannot be differentiated with respect to the underlying implicit field...

PURPOSE: Bayesian penalised likelihood (BPL) reconstruction, which incorporates point-spread-function (PSF) correction, provides higher signal-to-noise ratios and more accurate quantitation than conventional ordered subset expectation maximization (OSEM) reconstruction. However, applying PSF correction to brain PET imaging is controversial due to Gibbs artefacts that manifest as unpredicted cortical uptake enhancement. The present study aimed to validate whether BPL without PSF would be useful for amyloid PET imaging...

BACKGROUND: Herein, we present a proof-of-concept study of 3-dimensional (3D) pouchography using virtual and printed 3D models of ileal pouch-anal anastomosis (IPAA) in patients with normal pouches and in cases of mechanical pouch complications. MATERIALS & METHODS: We performed a retrospective, descriptive case series of a convenience sample of 10 pouch patients with or without pouch dysfunction who had CT scans appropriate for segmentation were identified from our pouch registry...

Conventional B-mode ultrasound imaging has difficulty in delineating homogeneous soft tissues with similar acoustic impedances, as the reflectivity depends on the acoustic impedance at the interface. As a quantitative imaging biomarker sensitive to alteration of biomechanical properties, speed-of-sound (SoS) holds promising potential for tissue and disease differentiation such as delineation of different breast tissue types with similar acoustic impedance. Compared to two-dimensional (2D) SoS images, three-dimensional (3D) volumetric SoS images achieved through a full-angle ultrasound scan can reveal more intricate morphological structures of tissues; however, they generally require a ring transducer...

Deuterium metabolic imaging (DMI) is an emerging magnetic resonance technique, for non-invasive mapping of human brain glucose metabolism following oral or intravenous administration of deuterium-labeled glucose. Regional differences in glucose metabolism can be observed in various brain pathologies, such as Alzheimer's disease, cancer, epilepsy or schizophrenia, but the achievable spatial resolution of conventional phase-encoded DMI methods is limited due to prolonged acquisition times rendering submilliliter isotropic spatial resolution for dynamic whole brain DMI not feasible...

Neuronal reconstruction-a process that transforms image volumes into 3D geometries and skeletons of cells- bottlenecks the study of brain function, connectomics and pathology. Unlike artistic domains with similar challenges (e.g., hair modeling), scientists need exact and complete segmentations to study subtle topological differences. Existing methods are diskbound, dense-access, coupled, single-threaded, algorithmically unscalable and require manual cropping of small windows and proofreading of skeletons due to low topological accuracy...

UNLABELLED: Across all electrical stimulation (neuromodulation) domains, conventional analysis of cell polarization involves two discrete steps: i) prediction of macroscopic electric field, ignoring presence of cells and; ii) prediction of cell polarization from tissue electric fields. The first step assumes that electric current flow is not distorted by the dense tortuous network of cell structures. The deficiencies of this assumption have long been recognized, but - except for trivial geometries - ignored, because it presented intractable computation hurdles...

While advances in single-particle cryoEM have enabled the structural determination of macromolecular complexes at atomic resolution, particle orientation bias (the so-called "preferred" orientation problem) remains a complication for most specimens. Existing solutions have relied on biochemical and physical strategies applied to the specimen and are often complex and challenging. Here, we develop spIsoNet, an end-to-end self-supervised deep-learning-based software to address the preferred orientation problem...

OrthoFusion, an intuitive super-resolution algorithm, is presented in this study to enhance the spatial resolution of clinical CT volumes. The efficacy of OrthoFusion is evaluated, relative to high-resolution CT volumes (ground truth), by assessing image volume and derived bone morphological similarity, as well as its performance in specific applications in 2D-3D registration tasks. Results demonstrate that OrthoFusion significantly reduced segmentation time, while improving structural similarity of bone images and relative accuracy of derived bone model geometries...

Bilateral Wilms tumour (BWT) is a surgically challenging condition. Virtual reality (VR) reconstruction aids surgeons to foresee the anatomy ahead of Nephron Sparing Surgery (NSS). Three-dimensional (3D) visualisation improves the anatomical orientation of surgeons performing NSS. We herewith report a case of BWT where VR planning and 3D printing were used to aid NSS. Conventional imaging is often found to be inadequate while assessing the tumour-organ-vascular anatomy. Advances like VR and 3D printing help surgeons plan better for complex surgeries like bilateral NSS...