Enhanced fetal MRI diagnosis of esophageal atresia using super-resolution slice-to-volume reconstruction.

Background: Prenatal diagnosis of esophageal atresia remains challenging, with indirect signs such as polyhydramnios, a small or absent stomach bubble, and a dilated upper esophageal pouch often inconsistently present. Only 10-40% of EA cases are diagnosed prenatally. Fetal MRI can overcome ultrasound limitations; however, constraints like motion can hinder evaluation of the esophagus.

Technical Feasibility of Delineating the Thalamic Gustatory Tract Using Tractography.

Background And Objectives: Magnetic resonance-guided focused ultrasound (MRgFUS) has been increasingly performed in recent years as a minimally invasive treatment of essential tremor and tremor-dominant Parkinson disease. One of the side effects after treatment is dysgeusia. Some centers use tractography to facilitate the treatment planning.

Four-dimensional fetal cardiac imaging in a cohort of fetuses with suspected congenital heart disease.

Background: Fetal cardiac magnetic resonance imaging (MRI) requires high spatial and temporal resolution and robustness to random fetal motion to capture the dynamics of the beating fetal heart. Slice-to-volume reconstruction techniques can produce high-resolution isotropic images while compensating for random fetal motion.

Objective: The objective of this study was to evaluate image quality for slice-to-volume reconstruction of four-dimensional balanced steady-state free precession (bSSFP) imaging of the fetal heart.

Radial sequences and compressed sensing in pediatric body magnetic resonance imaging.

Magnetic resonance imaging (MRI) is often an ideal imaging modality for children of any age for any anatomy and for many pathologies. MRI sequences can be prescribed to produce high-resolution images of anatomical structures, characterize tissue composition, and detect physiological states and organ function. Shortening imaging sequences in any manner possible has been a topic of research and development in MRI since its emergence.

Data Quality Assessment for Super-Resolution Fetal Brain MR Imaging: A Retrospective 1.5 T Study.

Background: Super-resolution is a promising technique to create isotropic image volumes from stacks of two-dimensional (2D) motion-corrupted images in fetal magnetic resonance imaging (MRI).

Purpose: To determine an acquisition quality metric and correlate that metric with radiologist perception of three-dimensional (3D) image quality.

Study Type: Retrospective.

Activated brown adipose tissue and its relationship to adiposity and metabolic markers: an exploratory study.

: To explore relationships between PET/CT characteristics of cold-activated brown adipose tissue (BAT), measures of adiposity and metabolic markers.: We conducted a post-hoc analysis of a study which utilized PET/CT to characterize BAT. 25 men ages 18-24 (BMI 19.

Evaluation of low-contrast detectability for iterative reconstruction in pediatric abdominal computed tomography: a phantom study.

Background: Iterative reconstruction is offered by all vendors to achieve similar or better CT image quality at lower doses than images reconstructed with filtered back-projection.

Objective: The purpose of this study was to investigate the dose-reduction potential for pediatric abdominal CT imaging when using either a commercially available hybrid or a commercially available model-based iterative reconstruction algorithm from a single manufacturer.

Materials And Methods: A phantom containing four low-contrast inserts and a uniform background with total attenuation equivalent to the abdomen of an average 8-year-old child was imaged on a CT scanner (IQon; Philips Healthcare, Cleveland, OH).

MRI characterization of brown adipose tissue under thermal challenges in normal weight, overweight, and obese young men.

Purpose: To implement quantitative Dixon magnetic resonance imaging (MRI) methods for brown adipose tissue (BAT) characterization at inactive and cold-activated states in normal weight, overweight, and obese subjects. The hypotheses are that MRI characteristics of BAT would differentiate between nonobese and obese subjects, and activation of BAT in response to thermal challenges that are detected by MRI would be correlated with BAT activity measured by positron emission tomography / computed tomography (PET/CT).

Materials And Methods: Fifteen male subjects (20.

Post-Procedure Evaluation of Microwave Ablations of Hepatocellular Carcinomas Using Electrode Displacement Elastography.

Microwave ablation has been used clinically as an alternative to surgical resection. However, lack of real-time imaging to assess treated regions may compromise treatment outcomes. We previously introduced electrode displacement elastography (EDE) for strain imaging and verified its feasibility in vivo on porcine animal models.

Improvement in CT image resolution due to the use of focal spot deflection and increased sampling.

When patient anatomy is positioned away from a CT scanner's isocenter, scans of limited diagnostic value may result. Yet in some cases, positioning of patient anatomy far from isocenter is unavoidable. This study examines the effect of posi-tion and reconstruction algorithm on image resolution achieved by a CT scanner operating in a high resolution (HR) scan mode which incorporates focal spot deflection and acquires an increased number of projections per rotation.

Technical Note: Confirming the prescribed angle of CT localizer radiographs and c-arm projection acquisitions.

Purpose: Accurate CT radiograph angle is not usually important in diagnostic CT. However, there are applications in radiation oncology and interventional radiology in which the orientation of the x-ray source and detector with respect to the patient is clinically important. The authors present a method for measuring the accuracy of the tube/detector assembly with respect to the prescribed tube/detector position for CT localizer, fluoroscopic, and general radiograph imaging using diagnostic, mobile, and c-arm based CT systems.

A Wiki Based CT Protocol Management System.

At the University of Wisconsin Madison Department of Radiology, CT protocol management requires maintenance of thousands of parameters for each scanner. Managing CT protocols is further complicated by the unique configurability of each scanner. Due to recent Joint Commission requirements, now all CT protocol changes must be documented and reviewed by a site's CT protocol optimization team.

CT protocol management: simplifying the process by using a master protocol concept.

This article explains a method for creating CT protocols for a wide range of patient body sizes and clinical indications, using detailed tube current information from a small set of commonly used protocols. Analytical expressions were created relating CT technical acquisition parameters which can be used to create new CT protocols on a given scanner or customize protocols from one scanner to another. Plots of mA as a function of patient size for specific anatomical regions were generated and used to identify the tube output needs for patients as a function of size for a single master protocol.

Alterations in Ultrasound Scattering Following Thermal Ablation in Bovine Liver.

Thermal ablation is a minimally invasive cancer treatment which has been rapidly gaining clinical acceptance. It is well known that thermal ablation increases the acoustic attenuation and shear modulus of tissue. In this work, we examine changes to the spatial distribution of scatterers in liver tissue following thermal ablation.

Mean scatterer spacing estimation using multi-taper coherence.

It has been hypothesized that estimates of mean scatterer spacing are useful indicators for pathological changes to the liver. A commonly employed estimator of the mean scatterer spacing is the location of the maximum of the collapsed average of coherence of the ultrasound radio-frequency signal. To date, in ultrasound, estimators for this quantity have been calculated with a single taper.

Scatterer number density considerations in reference phantom-based attenuation estimation.

Attenuation estimation and imaging have the potential to be a valuable tool for tissue characterization, particularly for indicating the extent of thermal ablation therapy in the liver. Often the performance of attenuation estimation algorithms is characterized with numerical simulations or tissue-mimicking phantoms containing a high scatterer number density (SND). This ensures an ultrasound signal with a Rayleigh distributed envelope and a signal-to-noise ratio (SNR) approaching 1.

Mean scatterer spacing estimation in normal and thermally coagulated ex vivo bovine liver.

The liver has been hypothesized to have a unique arrangement of microvasculature that presents as an arrangement of quasiperiodic scatterers to an interrogating ultrasound pulse. The mean scatterer spacing (MSS) of these quasiperiodic scatterers has been proposed as a useful quantitative ultrasound biomarker for characterizing liver tissue. Thermal ablation is an increasingly popular method for treating hepatic tumors, and ultrasonic imaging approaches for delineating the extent of thermal ablation are in high demand.

Coherence of Ultrasound Radiofrequency Echoes from the Liver Estimated Using Multi-Taper Calculation.

Acoustic scattering from the microvasculature in the liver is frequently modeled by a quasi-periodic distribution of point scatterers. The received echoes from such an arrangement of scatterers has random but correlated phase at frequency components corresponding to the average spacing of the quasi-periodic scatterers. The extent of the correlation between different frequency components is measured by calculating signal coherence.

Ultrasound attenuation measurements using a reference phantom with sound speed mismatch.

Ultrasonic attenuation may be measured accurately with clinical systems and array transducers by using reference phantom methods (RPM) to account for diffraction and other system dependencies on echo signals. Assumptions with the RPM are that the speeds of sound in the sample (c(sam)) and in the reference medium (c(ref)) are the same and that they match the speed assumed in the system beamformer (c(bf)). This work assesses the accuracy of attenuation measurements by the RPM when these assumptions are not met.

Bayesian regularization applied to ultrasound strain imaging.

Noise artifacts due to signal decorrelation and reverberation are a considerable problem in ultrasound strain imaging. For block-matching methods, information from neighboring matching blocks has been utilized to regularize the estimated displacements. We apply a recursive Bayesian regularization algorithm developed by Hayton et al.