Demonstrating the use of population level data to investigate trends in the rate, radiation dose and cost of Computed Tomography across clinical groups: Are there any areas of concern?

Introduction: Increases in computed tomography (CT) use may not always reflect clinical need or improve outcomes. This study aimed to demonstrate how population level data can be used to identify variations in care between patient groups, by analysing system-level changes in CT use around the diagnosis of new conditions.

Methods: Retrospective repeated cross-sectional observational study using West Australian linked administrative records, including 504,723 adults diagnosed with different conditions in 2006, 2012 and 2015.

Use of CT, ED presentation and hospitalisations 12 months before and after a diagnosis of cancer in Western Australia: a population-based retrospective cohort study.

Objective: To examine the use of CT, emergency department (ED)-presentation and hospitalisation and in 12 months before and after a diagnosis of cancer.

Design: Population-based retrospective cohort study.

Setting: West Australian linked administrative records at individual level.

Patterns of computed tomography utilisation in injury management: latent classes approach using linked administrative data in Western Australia.

Purpose: Whilst computed tomography (CT) imaging has been a vital component of injury management, its increasing use has raised concern regarding ionising radiation exposure. This study aims to identify latent classes (underlying patterns) of CT use over a 3-year period following the incidence of injury and factors predicting the observed patterns.

Method: A retrospective observational cohort study was conducted in 21,544 individuals aged 18 + years presenting to emergency departments (ED) of four tertiary public hospitals with new injury in Western Australia.

Trend in CT utilisation and its impact on length of stay, readmission and hospital mortality in Western Australia tertiary hospitals: an analysis of linked administrative data 2003-2015.

Objective: High use of CT scanning has raised concern due to the potential ionising radiation exposure. This study examined trends of CT during admission to tertiary hospitals and its associations with length of stay (LOS), readmission and mortality.

Design: Retrospective observational study from 2003 to 2015.

Factors driving CT utilisation in tertiary hospitals: a decomposition analysis using linked administrative data in Western Australia.

Objectives: While CT scanning plays a significant role in healthcare, its increasing use has raised concerns about inappropriate use. This study investigated factors driving the changing use of CT among people admitted to tertiary hospitals in Western Australia (WA).

Design And Setting: A repeated cross-sectional study of CT use in WA in 2003-2005 and 2013-2015 using linked administrative heath data at the individual patient level.

The use of computed tomography in the management of injury in tertiary emergency departments in Western Australia: Evidence of overtesting?

Background: This study investigated trends in computed tomography (CT) utilization across different triage categories of injury presentations to tertiary emergency departments (EDs) and associations with diagnostic yield measured by injury severity, hospitalization and length of stay (LOS), and mortality.

Methods: A total of 411,155 injury-related ED presentations extracted from linked records from Western Australia from 2004 to 2015 were included in the retrospective study. The use of CT scanning and diagnostic yield measured by rate of diagnosis with severe injury, hospitalizations and LOS, and mortality were captured annually for injury-related ED presentations.

Increasing use of CT requested by emergency department physicians in tertiary hospitals in Western Australia 2003-2015: an analysis of linked administrative data.

Objective: This study aimed to examine trends in number of CT scans requested by tertiary emergency department (ED) physicians in Western Australia (WA) from 2003 to 2015 across broad demographic and presentation characteristics, anatomical areas and presented symptoms.

Design: An observational cross-sectional study over study period from 2003 to 2015.

Setting: Linked administrative health service data at individual level from WA.

Muscle and bone dose in paediatric limb digital radiography: a Monte Carlo evaluation.

The proliferation of digital radiography (DR) has led to a re-evaluation of exposure parameters and image quality. Currently, there is a move towards reducing X-ray tube voltage (kVp) in paediatric exposures down to 40 kVp to achieve better images. However, the effect on patient dose of these modifications is uncertain.

How have advances in CT dosimetry software impacted estimates of CT radiation dose and cancer incidence? A comparison of CT dosimetry software: Implications for past and future research.

Objective: Organ radiation dose from a CT scan, calculated by CT dosimetry software, can be combined with cancer risk data to estimate cancer incidence resulting from CT exposure. We aim to determine to what extent the use of improved anatomical representation of the adult human body "phantom" in CT dosimetry software impacts estimates of radiation dose and cancer incidence, to inform comparison of past and future research.

Methods: We collected 20 adult cases for each of three CT protocols (abdomen/pelvis, chest and head) from each of five public hospitals (random sample) (January-April inclusive 2010) and three private clinics (self-report).

Detection of maturity and ligament injury using magic angle directional imaging.

Purpose: To investigate whether magnetic field-related anisotropies of collagen may be correlated with postmortem findings in animal models.

Methods: Optimized scan planning and new MRI data-processing methods were proposed and analyzed using Monte Carlo simulations. Six caprine and 10 canine knees were scanned at various orientations to the main magnetic field.

Comparison between diffusion-weighted MRI (DW-MRI) at 1.5 and 3 tesla: a phantom study.

Purpose: To compare DW-MRI between 1.5 and 3 Tesla (T) in terms of image quality, apparent diffusion coefficient (ADC), reproducibility, lesion-to-background contrast and signal-to-noise ratio (SNR), using a test object.

Materials And Methods: A spherical diffusion phantom was used for qualitatively assessing image quality and performing quantitative measurements between the two field strengths.

A phantom for diffusion-weighted MRI (DW-MRI).

Purpose: To develop tissue-equivalent diffusivity materials and build a spherical diffusion phantom which mimics the conditions typically found in biological tissues. Also, to assess the reproducibility of ADC measurements from a whole-body diffusion protocol.

Materials And Methods: Nickel-doped agarose/sucrose gels were manufactured and used to build a spherical diffusion phantom with tissue-equivalent relaxation and diffusion compartments.

Pseudotumors in association with well-functioning metal-on-metal hip prostheses: a case-control study using three-dimensional computed tomography and magnetic resonance imaging.

Introduction: Many papers have been published recently on the subject of pseudotumors surrounding metal-on-metal hip resurfacing and replacement prostheses. These pseudotumors are sterile, inflammatory lesions within the periprosthetic tissues and have been variously termed masses, cysts, bursae, collections, or aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL). The prevalence of pseudotumors in patients with a well-functioning metal-on-metal hip prosthesis is not well known.

Numerical simulation of SAR induced around Co-Cr-Mo hip prostheses in situ exposed to RF fields associated with 1.5 and 3 T MRI body coils.

When patients with metallic prosthetic implants undergo an MR procedure, the interaction between the RF field and the prosthetic device may lead to an increase in specific absorption rate (SAR) in tissues surrounding the prosthesis. In this work, the distribution of SAR(10g) around bilateral CoCrMo alloy hip prostheses in situ in anatomically realistic voxel models of an adult male and female due to RF fields from a generic birdcage coil driven at 64 or 128 MHz are predicted using a time-domain finite integration technique. Results indicate that the spatial distribution and maximum values of SAR(10g) are dependent on body model, frequency, and the position of the coil relative to the body.

Functional MRI brain imaging studies using the Contact Heat Evoked Potential Stimulator (CHEPS) in a human volunteer topical capsaicin pain model.

Acute application of topical capsaicin produces spontaneous burning and stinging pain similar to that seen in some neuropathic states, with local hyperalgesia. Use of capsaicin applied topically or injected intradermally has been described as a model for neuropathic pain, with patterns of activation in brain regions assessed using functional magnetic resonance imaging (fMRI) and positron emission tomography. The Contact Heat Evoked Potential Stimulator (CHEPS) is a noninvasive clinically practical method of stimulating cutaneous A-delta nociceptors.

Return of spinal reflex after spinal cord surgery for brachial plexus avulsion injury.

Motor but not sensory function has been described after spinal cord surgery in patients with brachial plexus avulsion injury. In the featured case, motor-related nerve roots as well as sensory spinal nerves distal to the dorsal root ganglion were reconnected to neurons in the ventral and dorsal horns of the spinal cord by implanting nerve grafts. Peripheral and sensory functions were assessed 10 years after an accident and subsequent spinal cord surgery.

Biasing visual selection: functional neuroimaging of the interplay between spatial cueing and feature memory guidance.

The authors investigate the interplay between spatial attention and memory-based feature guidance of visual selection. Three types of guidance were tested: working memory, spatial cueing and passive memory. In all cases the memory-cue was not relevant to a subsequent search task, whilst the spatial cue always provided valid information.

In vivo-in vitro correlations: predicting pulmonary drug deposition from pharmaceutical aerosols.

In order to answer the question "what research remains to be done?" we review the current state of the art in pharmaceutical aerosol deposition modeling and explore possible in vivo- in vitro correlations (IVIVC) linking drug deposition in the human lung to predictions made using in vitro physical airway models and in silico computer models. The use of physical replicas of portions of the respiratory tract is considered, alongside the advantages and disadvantages of the different imaging methods used to obtain their dimensions. The use of airway replicas to determine drug deposition in vitro is discussed and compared with the predictions from different empirical curve fits to long-standing in vivo deposition data for monodisperse aerosols.

Robotic system for transrectal biopsy of the prostate: real-time guidance under MRI.

In this paper, to harness the possibility of real-time guidance of MRI, a robotic system has been developed to perform transrectal prostate biopsy inside a 1.5-T closed bore scanner. A specially developed MR pulse sequence is capable of tracking the needle location in real time while dynamically updating the scan planes to always include the needle and target.

Contact Heat Evoked Potentials Using Simultaneous Eeg And Fmri And Their Correlation With Evoked Pain.

Background: The Contact Heat Evoked Potential Stimulator (CHEPS) utilises rapidly delivered heat pulses with adjustable peak temperatures to stimulate the differential warm/heat thresholds of receptors expressed by Adelta and C fibres. The resulting evoked potentials can be recorded and measured, providing a useful clinical tool for the study of thermal and nociceptive pathways. Concurrent recording of contact heat evoked potentials using electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) has not previously been reported with CHEPS.

Sub-pixel localisation of passive micro-coil fiducial markers in interventional MRI.

Objective: Electromechanical devices enable increased accuracy in surgical procedures, and the recent development of MRI-compatible mechatronics permits the use of MRI for real-time image guidance. Integrated imaging of resonant micro-coil fiducials provides an accurate method of tracking devices in a scanner with increased flexibility compared to gradient tracking. Here we report on the ability of ten different image-processing algorithms to track micro-coil fiducials with sub-pixel accuracy.

A MR compatible mechatronic system to facilitate magic angle experiments in vivo.

When imaging tendons and cartilage in a MRI scanner, an increase in signal intensity is observed when they are oriented at 55 degrees with respect to Bo (the "magic angle"). There is a clear clinical importance for considering this effect as part of the diagnosis of orthopaedic and other injury. Experimental studies of this phenomenon have been made harder by practical difficulties of tissue positioning and orientation in the confined environment of cylindrical scanners.