3D X-ray Histology for the Investigation of Temporal Lobe Epilepsy in a Mouse Model.

The most common form of epilepsy among adults is mesial temporal lobe epilepsy (mTLE), with seizures often originating in the hippocampus due to abnormal electrical activity. The gold standard for the histopathological analysis of mTLE is histology, which is a two-dimensional technique. To fill this gap, we propose complementary three-dimensional (3D) X-ray histology.

Zebrafish (Danio rerio) larvae as a predictive model to study gentamicin-induced structural alterations of the kidney.

Nephrotoxicity is an important drug safety aspect to be assessed during drug discovery and development. To study renal toxicity, in vitro cell-based assays are often used. Unfortunately, translating the results of such cell assays to vertebrates including human remains challenging.

Three-dimensional analysis of aligner gaps and thickness distributions, using hard x-ray tomography with micrometer resolution.

Purpose: The morphology of a polymer aligner, designed according to an orthodontic treatment plan, determines clinical outcomes. A fundamental element of orthodontic tooth movement with aligner treatment is the fit of the aligner's surface to the individual teeth. Gaps between the aligner and teeth do occur because current aligner fabrication is not capable of completely reproducing the complex anatomy of the individual denture.

Comparative hard x-ray tomography for virtual histology of zebrafish larva, human tooth cementum, and porcine nerve.

Synchrotron radiation-based tomography yields microanatomical features in human and animal tissues without physical slicing. Recent advances in instrumentation have made laboratory-based phase tomography feasible. We compared the performance of three cutting-edge laboratory systems benchmarked by synchrotron radiation-based tomography for three specimens.

Virtual histology of an entire mouse brain from formalin fixation to paraffin embedding. Part 2: Volumetric strain fields and local contrast changes.

Background: Fixation and embedding of post mortem brain tissue is a pre-requisite for both gold-standard conventional histology and X-ray virtual histology. This process alters the morphology and density of the brain microanatomy.

New Method: To quantify these changes, we employed synchrotron radiation-based hard X-ray tomography with 3 μm voxel length to visualize the same mouse brain after fixation in 4% formalin, immersion in ethanol solutions (50%, 70%, 80%, 90%, and 100%), xylene, and finally after embedding in a paraffin block.

Virtual histology of an entire mouse brain from formalin fixation to paraffin embedding. Part 1: Data acquisition, anatomical feature segmentation, tracking global volume and density changes.

Background: Micrometer-resolution neuroimaging with gold-standard conventional histology requires tissue fixation and embedding. The exchange of solvents for the creation of sectionable paraffin blocks modifies tissue density and generates non-uniform brain shrinkage.

New Method: We employed synchrotron radiation-based X-ray microtomography for slicing- and label-free virtual histology of the mouse brain at different stages of the standard preparation protocol from formalin fixation via ascending ethanol solutions and xylene to paraffin embedding.

Ultrasound simulation with deformable and patient-specific scatterer maps.

Purpose: Ray-tracing-based simulations model ultrasound (US) interactions with a custom geometric anatomical model, where US texture can be emulated via real-time point-spread function convolutions of a tissue scatterer representation. Such scatterer representations for realistic appearance are difficult to parameterize or model manually and do not respond to volumetric deformations such as those caused with tissue compression by the probe. Herein we utilize brightness mode (B-mode) estimated scatterer maps for ray tracing and propose to enhance the realism of ray-tracing-based simulations by incorporating dynamic speckle patterns that change compliant with tissue deformation.

A comprehensive and volumetric musculoskeletal model for the dynamic simulation of the shoulder function.

We present a volumetric and extensive finite element model of the shoulder usable in the context of inverse control, in which the scapula is left unconstrained on the ribcage. Such a model allows for exploring various shoulder movements, which are essential for making patient-specific decisions. The proposed model consists of 23 volumetric muscles parts modelled using the finite element method.

An image interpolation approach for acquisition time reduction in navigator-based 4D MRI.

Navigated 2D multi-slice dynamic Magnetic Resonance (MR) imaging enables high contrast 4D MR imaging during free breathing and provides in-vivo observations for treatment planning and guidance. Navigator slices are vital for retrospective stacking of 2D data slices in this method. However, they also prolong the acquisition sessions.

ELPHA: Dynamically deformable liver phantom for real-time motion-adaptive radiotherapy treatments.

Purpose: Real-time motion-adaptive radiotherapy of intrahepatic tumors needs to account for motion and deformations of the liver and the target location within. Phantoms representative of anatomical deformations are required to investigate and improve dynamic treatments. A deformable phantom capable of testing motion detection and motion mitigation techniques is presented here.

Evaluation of 2D and 3D ultrasound tracking algorithms and impact on ultrasound-guided liver radiotherapy margins.

Purpose: Compensation for respiratory motion is important during abdominal cancer treatments. In this work we report the results of the 2015 MICCAI Challenge on Liver Ultrasound Tracking and extend the 2D results to relate them to clinical relevance in form of reducing treatment margins and hence sparing healthy tissues, while maintaining full duty cycle.

Methods: We describe methodologies for estimating and temporally predicting respiratory liver motion from continuous ultrasound imaging, used during ultrasound-guided radiation therapy.

Reducing Navigators in Free-Breathing Abdominal MRI via Temporal Interpolation Using Convolutional Neural Networks.

Navigated 2-D multi-slice dynamic magnetic resonance imaging (MRI) acquisitions are essential for MR guided therapies. This technique yields time-resolved volumetric images during free-breathing, which are ideal for visualizing and quantifying breathing induced motion. To achieve this, navigated dynamic imaging requires acquiring multiple navigator slices.

Registration of 3D freehand ultrasound to a bone model for orthopedic procedures of the forearm.

Purpose: For guidance of orthopedic surgery, the registration of preoperative images and corresponding surgical plans with the surgical setting can be of great value. Ultrasound (US) is an ideal modality for surgical guidance, as it is non-ionizing, real time, easy to use, and requires minimal (magnetic/radiation) safety limitations. By extracting bone surfaces from 3D freehand US and registering these to preoperative bone models, complementary information from these modalities can be fused and presented in the surgical realm.

Care coordination: Identifying and connecting the most appropriate care to the patients.

Although nurses are increasingly expected to fulfill the role of care coordinator, the knowledge and skills required to be an effective care coordinator are not well understood. The purpose of this study was to describe the knowledge and skills required in care coordination practice using an interpretive phenomenological approach. Fifteen care coordinators from 10 programs were interviewed over a 6-month period.

Automatic registration of 2D histological sections to 3D microCT volumes: Trabecular bone.

Histomorphometry and microCT are the two dominant imaging techniques to study bone structure and quality to evaluate repair, regeneration, and disease. These two methods are complementary; where histology provides highly resolved tissue properties on a cellular level in 2D, microCT provides spatial information of bone micro-structure in 3D. For this reason, both of these modalities are commonly used in bone studies.

A focused ultrasound treatment system for moving targets (part I): generic system design and in-silico first-stage evaluation.

Background: Focused ultrasound (FUS) is entering clinical routine as a treatment option. Currently, no clinically available FUS treatment system features automated respiratory motion compensation. The required quality standards make developing such a system challenging.

Consistent reconstruction of 4D fetal heart ultrasound images to cope with fetal motion.

Purpose: 4D ultrasound imaging of the fetal heart relies on reconstructions from B-mode images. In the presence of fetal motion, current approaches suffer from artifacts, which are unrecoverable for single sweeps.

Methods: We propose to use many sweeps and exploit the resulting redundancy to automatically recover from motion by reconstructing a 4D image which is consistent in phase, space, and time.

Robust motion tracking in liver from 2D ultrasound images using supporters.

Purpose: Effectiveness of image-guided radiation therapy with precise dose delivery depends highly on accurate target localization, which may involve motion during treatment due to, e.g., breathing and drift.

Isotropic Total Variation Regularization of Displacements in Parametric Image Registration.

Spatial regularization is essential in image registration, which is an ill-posed problem. Regularization can help to avoid both physically implausible displacement fields and local minima during optimization. Tikhonov regularization (squared l -norm) is unable to correctly represent non-smooth displacement fields, that can, for example, occur at sliding interfaces in the thorax and abdomen in image time-series during respiration.

Pursuing Improvement in Clinical Reasoning: Development of the Clinical Coaching Interactions Inventory.

Background: Clinical coaching has been identified as a signature pedagogy in nursing education. Recent findings indicate that clinical coaching interactions in the clinical learning environment fail to engage students in the higher order thinking skills believed to promote clinical reasoning.

Method: The Clinical Coaching Interactions Inventory (CCII) was based on evidence of supervisor questioning techniques, the Tanner clinical judgment model, Bloom's Taxonomy, and simulation evaluation tools.

Estimation of Large-Scale Organ Motion in B-Mode Ultrasound Image Sequences: A Survey.

Reviewed here are methods developed for following (i.e., tracking) structures in medical B-mode ultrasound time sequences during large-scale motion.

An integrated model-based software for FUS in moving abdominal organs.

Focused ultrasound surgery (FUS) is a non-invasive method for tissue ablation that has the potential for complete and controlled local tumour destruction with minimal side effects. The treatment of abdominal organs such as the liver, however, requires particular technological support in order to enable a safe, efficient and effective treatment. As FUS is applied from outside the patient's body, suitable imaging methods, such as magnetic resonance imaging or diagnostic ultrasound, are needed to guide and track the procedure.

Detection and registration of ribs in MRI using geometric and appearance models.

Magnetic resonance guided high intensity focused ultrasound (MRgHIFU) is a new type of minimally invasive therapy for treating malignant liver tissues. Since the ribs on the beam path can compromise an effective therapy, detecting them and tracking their motion on MR images is of great importance. However, due to poor magnetic signal emission of bones, ribs cannot be entirely observed in MR.