Survey of maternal anxiety and perceptions towards foetal MRI and pre-scan education.

INTRODUCTION: Foetal MRI scans can induce feelings of fear, concern and anxiety in pregnant patients. The aim of this research was to determine if providing patients with an information leaflet reduced maternal anxiety regarding foetal MRI. METHODS: A prospective, three-arm comparative pilot study was performed in the MRI department of a quaternary public hospital in Brisbane, Australia. Three groups of 30 participants (total 90 participants) received differing levels of information about foetal MRI: Group A - no foetal-MRI specific information (current practice at the site); Group B - a basic information leaflet; Group C - a comprehensive information leaflet. All participants completed a survey that explored their pre-scan anxiety immediately after their MRI scan. RESULTS: Over 50% of participants in each group felt anxious before the MRI. Participants expressed anxiety towards the general process of the MRI, the outcome or results of the scan, and the safety of the modality. The basic and comprehensive leaflets were both efficacious in reducing anxiety for the majority of participants. CONCLUSIONS: Whilst not all patients express anxiety regarding MRI scans, emotional distress surrounding the entire process is prevalent. Providing patients with comprehensive information about what the MRI scan entails (including the scan environment and duration, positioning, breath-holding requirements, and foetal safety) reduces anxiety for most patients. These findings can be used to determine ways in which reduction of anxiety improves the patient experience.

Perforated intravenous catheter design is acceptable for the administration of contrast-enhanced computed tomography administration in cancer patients: Results of a pilot randomised controlled trial.

BACKGROUND: Optimising first time success of peripheral intravenous catheter (PIVC) insertion and reducing intravenous (IV) complications in cancer patients undergoing contrast-enhanced computed tomography (CT) is vital to ensure vascular access preservation and diagnostic accuracy. The aim of this study was to test the feasibility of a randomised controlled trial (RCT) evaluating a novel perforated PIVC compared to a standard PIVC. METHODS: A single centre, parallel-group, pilot RCT was conducted between March and May 2020. Adult participants diagnosed with cancer were randomised to a non-perforated PIVC (standard care) or a PIVC with a novel perforated design (intervention) for the administration of IV contrast. There were two primary outcomes: (1) feasibility of an adequately powered RCT with pre-established criteria; and (2) all-cause PIVC failure. Secondary outcomes included: first insertion success, modes of PIVC failure, dwell time, contrast injection parameters (volume and injection rate), contrast enhancement, radiographer satisfaction and adverse events. RESULTS: Feasibility outcomes were met, except for eligibility (⩾90%) and recruitment (⩾90%). In total, 166 participants were screened, 128 (77%) were eligible and of these 101/128 (79%) were randomised; 50 to standard care and 51 to intervention. First time insertion rate was 94% (47/50) in standard care and 90% (46/50) in intervention. The median dwell time was 37 minutes (interquartile range (IQR): 25-55) in standard care and 35 minutes (IQR: 25-60) in the intervention group. There was one PIVC failure, a contrast media extravasation, in the intervention group (1/51; 2%). The desired contrast injection rate was not achieved in 4/101 (4%) of participants; two from each group. Radiographers were satisfied with the contrast flow rate. CONCLUSIONS: This pilot RCT suggests perforated PIVCs provide expected flow rate, with no evidence of differences in contrast enhancement to non-perforated PIVCs. The feasibility of conducting a larger powered RCT was demonstrated.

Radiographic technique modification and evidence-based practice: A qualitative study.

INTRODUCTION: Evidence-based practice in radiography is an emerging practice, due to a lack of evidence. Beyond the diagnostic requirements of the examination, imaging technique decisions are guided by the radiographer's tertiary education and clinical experience. Imaging technique decisions should include all aspects of evidence-based practice: research-based evidence, patient circumstances and clinical experience. Previous research suggests radiographers do to not fully engage with the latter, which may jeopardise progress in the field and lead to outdated practices and suboptimal outcomes for patients. This study aimed to examine the motivators and influences involved in radiographers' decision-making when modifying imaging acquisition techniques. METHODS: An exploratory descriptive, inductive qualitative interview-based design was used with a convenience sample of radiographers from three public hospital sites in Queensland. Twelve one-on-one semi-structured interviews were performed via video conference, the data were analysed through thematic analysis. RESULTS: Five themes emerged from the data: advancement of technology; experience rather than evidence; radiology's influence on radiographic practice; information sources; and image quality. The pursuit of image quality was the key motivator and criterion that influenced radiographers' choices in imaging technique modification. Interviewees did not engage routinely with research-based evidence, preferring to rely on empirical observations and professional experience. CONCLUSION: The exclusion of research-based evidence can lead to outdated and ineffective clinical decisions. Further work is needed to promote more research in the field of radiography and increase the willingness and capacity of radiographers to follow the principles of evidence-based practice.

Sensitivity of virtual non-contrast dual-energy CT urogram for detection of urinary calculi: a systematic review and meta-analysis.

OBJECTIVE: To determine the sensitivity of dual-energy (DE) virtual non-contrast computed tomography (vNCT), generated from the excretory phase of a CT urogram, compared to true non-contrast CT (tNCT) for the detection of urinary calculi. METHODS: A search of multiple medical literature databases was performed using predetermined search terms. Inclusion and exclusion criteria were applied, and bias risk was assessed by two independent reviewers using the quality assessment of diagnostic accuracy studies (QUADAS) tool. Collated estimates of sensitivity were generated, and sources of heterogeneity were identified and reviewed. RESULTS: Thirteen studies (1760 patients; 1740 urinary calculi) were included for sensitivity assessment. Pooled sensitivity for urinary calculi on vNCT was 78.1% (95% CI: 70.2 to 85.0%); however, heterogeneity between studies was very high (I2 = 92.0%). Sources of heterogeneity between studies were explored through subgroup analysis by categorising studies according to slice thickness (≥ 2 mm and < 2 mm), use of oral hydration, and use of intravenous furosemide. Pooled sensitivity for detection of urinary calculi on vNCT for studies that used oral hydration and < 2 mm slice thickness was 92.2% (95% CI: 89.5 to 94.5%). Pooled specificity was not performed as true negatives were not reported in most studies. Potential sources of bias were identified in included studies. CONCLUSION: vNCT demonstrated a moderate pooled sensitivity compared to tNCT for the detection of urinary calculi in split bolus CT urogram protocols. However, subgroup analysis suggests higher sensitivity when employing oral hydration and < 2 mm slice thickness or increment. KEY POINTS: • vNCT demonstrated moderate pooled sensitivity for the detection of urinary calculi in split bolus CT urogram protocols. • Subgroup analysis suggested higher sensitivity with oral hydration and < 2 mm slice thickness or increment.

Virtual non-contrast detector-based spectral CT predictably overestimates tissue density for the characterisation of adrenal lesions compared to true non-contrast CT.

PURPOSE: To establish if virtual non-contrast (VNC) images generated from contrast-enhanced detector-based spectral CT could replace true non-contrast (TNC) imaging for the characterisation of adrenal masses. METHODS: TNC and VNC images were retrospectively reviewed for 39 patients with one or more adrenal lesions who underwent contrast-enhanced spectral CT of the upper abdomen. Lesions were categorised as either 'adenoma' or 'indeterminate/other lesion' based on current reference standards. The CT density of each lesion was measured on both image sets by two readers and compared using Wilcoxon signed-rank test. ROC analysis with Youden's J index method was performed to determine the optimal attenuation cut-off for diagnosing benign adenoma on VNC images. RESULTS: Forty-four lesions were included, 37 of which were diagnosed as adenomas. There were significant differences between TNC and VNC measurements for both readers (mean difference 9.1 HU for reader 1; 9.8 HU for reader 2; p < 0.01). Optimal attenuation thresholds for diagnosing adenomas on VNC were 25.3 HU (reader 1) and 23.9 HU (reader 2) for the entire population, and 18.3 HU (reader 1) and 19.7 HU (reader 2) for lipid-rich adenomas < 10 HU on TNC imaging. CONCLUSION: There is insufficient evidence to support the use of VNC as a substitute for TNC images in the characterisation of adrenal lesions. VNC using a detector-based spectral CT scanner shows a predictable increase in attenuation values compared to TNC. Thus, future studies might be better directed towards finding a new threshold value for diagnosing benign adrenal adenomas on VNC imaging.

Diagnostic accuracy of prospectively gated, 128-slice or greater CTCA at high heart rates: a systematic review and meta-analysis.

INTRODUCTION: Prospectively gated 64-slice CT coronary angiography (CTCA) may be contraindicated for heart rates (HRs) over 65 beats per minute (bpm) due to reduced diagnostic sensitivity. Newer CT scanners typically provide 128 or more slices and superior temporal resolution compared with older models; consequently, diagnostic accuracy for current technology prospectively gated CTCA may be adequate at HRs above 65 bpm. The aim of this systematic review was to investigate the diagnostic accuracy of CTCA using 128-slice or greater CT technology when compared with conventional coronary angiography for patients with HRs >65 bpm. METHODS: A systematic search of PubMed, CINAHL, EMBASE and Scopus was performed as well as unpublished databases, sources and reference lists. Titles and abstracts were screened by two independent reviewers. Full-text screening was then performed. Studies that determined diagnostic accuracy of coronary artery stenosis in adult patients with high heart rates utilising prospectively gated 128 detector or greater scanners were included. Studies that were included in the review underwent critical appraisal using the QUADAS-2 tool. RESULTS: Ten studies were included in the systematic review, with nine of these included in a diagnostic test accuracy meta-analysis, including six of which reported data at the patient level. Meta-analysis indicated very high pooled sensitivity 100% (95% CI 0.99, 1.00); however, pooled specificity was less at 79% (95% CI 0.69, 0.88). CONCLUSIONS: Prospectively gated CT coronary angiography may be justifiable at heart rates above 65 bpm if performed on a 128-slice or greater CT unit. Caution regarding the implication of a positive result is recommended due to reduced specificity. Further evidence is required before consideration of a new higher heart threshold.

Diagnostic accuracy of computed tomography coronary angiography utilizing recent advances in technology in patients with high heart rates: a systematic review protocol.

OBJECTIVE: The objective of this review is to determine the diagnostic accuracy of computed tomography coronary angiography (CTCA) using recent scan technologies for detecting coronary artery disease (CAD) in adults with high heart rates. INTRODUCTION: Invasive coronary angiography is the gold standard for detecting significant CAD, but it is costly and carries risks of complications. Computed tomography coronary angiography has a high sensitivity for diagnosing CAD, although image quality may be affected by elevated heart rates. Recent technological advances in scanner design may increase the diagnostic accuracy of CTCA. INCLUSION CRITERIA: This review will consider diagnostic test accuracy studies that include adults 18 years and older with a heart rate greater than 65 beats per minute who have undergone CTCA to diagnose CAD (greater than 50% stenosis). Eligible studies will compare invasive coronary angiography with computed tomography scanner technologies that use either single- or dual-source scanner configuration in prospective electrocardiogram scan acquisition mode, and with a total scanner coverage equal to or greater than 128 detector-rows. Studies published in English from 2007 will be considered. METHODS: PubMed, Embase, CINAHL and Scopus will be searched, along with Google Scholar, the NIHR-HTA register, computed tomography vendors and conference abstracts. Screening of potential titles and abstracts, retrieval of full-text studies, assessment of methodological quality and data extraction will be performed independently by two reviewers. Meta-analyses will be performed, if possible, and a Grading of Recommendations, Assessment, Development and Evaluation (GRADE) Summary of Findings presented.

Exposure (mAs) optimisation of a multi-detector CT protocol for hepatic lesion detection: Are thinner slices better?

INTRODUCTION: The purpose of this work was to determine the exposure-optimised slice thickness for hepatic lesion detection with CT. METHODS: A phantom containing spheres (diameter 9.5, 4.8 and 2.4 mm) with CT density 10 HU below the background (50 HU) was scanned at 125, 100, 75 and 50 mAs. Data were reconstructed at 5-, 3- and 1-mm slice thicknesses. Noise, contrast-to-noise ratio (CNR), area under the curve (AUC) as calculated using receiver operating characteristic analysis and sensitivity representing lesion detection were calculated and compared. RESULTS: Compared with the 125 mAs/5 mm slice thickness setting, significant reductions in AUC were found for 75 mAs (P < 0.01) and 50 mAs (P < 0.05) at 1- and 3-mm thicknesses, respectively; sensitivity for the 9.5-mm sphere was significantly reduced for 75 (P < 0.05) and 50 mAs (P < 0.01) at 1-mm thickness; sensitivity for the 4.8-mm sphere was significantly lower for 100, 75 and 50 mAs at all three slice thicknesses (P < 0.05). The 2.4-mm sphere was rarely detected. At each slice thickness, noise at 100, 75 and 50 mAs exposures was approximately 10, 30 and 50% higher, respectively, than that at 125 mAs exposure. CNRs decreased in an irregular manner with reductions in exposure and slice thickness. CONCLUSION: This study demonstrated no advantage to using slices below 5 mm thickness, and consequently thinner slices are not necessarily better.

Optimization of computed tomography protocols: limitations of a methodology employing a phantom with location-known opacities.

This study aimed to determine if phantom-based methodologies for optimization of hepatic lesion detection with computed tomography (CT) require randomization of lesion placement and inclusion of normal images. A phantom containing fixed opacities of varying size (diameters, 2.4, 4.8, and 9.5 mm) was scanned at various exposure and slice thickness settings. Two image sets were compared: All images in the first image set contained opacities with known location; the second image set contained images with opacities in random locations. Following Institutional Review Board approval, nine experienced observers scored opacity visualization using a 4-point confidence scale. Comparisons between image sets were performed using Spearman, Kappa, and Wilcoxon techniques. Observer scores demonstrated strong correlation between both approaches when all opacity sizes were combined (r = 0.92, p < 0.0001), for the 9.5 mm opacity (r = 0.96, p < 0.0001) and for the 2.4 mm opacity (r = 0.64, p < 0.05). There was no significant correlation for the 4.8 mm opacity. A significantly higher sensitivity score for the known compared with the unknown location was found for the 9.5 mm opacity and 4.8 mm opacity for a single slice thickness and exposure condition (p < 0.05). Phantom-based optimization of CT hepatic examinations requires randomized lesion location when investigating challenging conditions; however, a standard phantom with fixed lesion location is suitable for the optimization of routine liver protocols. The development of more sophisticated phantoms or methods than those currently available is indicated for the optimization of CT protocols for diagnostic tasks involving the detection of subtle change.

Physician-performed ultrasound can accurately screen for a vulnerable intercostal artery prior to chest drainage procedures.

BACKGROUND AND OBJECTIVE: Laceration of the intercostal artery during pleural procedures is a rare but serious complication. This study evaluates the utility of thoracic ultrasound (US) to screen for a vulnerable vessel compared with the gold standard computed tomography (CT). METHODS: Before undergoing contrast-enhanced CT chest, thoracic US was performed on 50 patients with a high-end and portable machine, and an attempt made to visualize the vessel at three positions across the back to the axilla. These positions were labelled with radio-opaque fiducial markers. On both US and CT images, the location of the vessel at each position, relative to the overlying rib, was calculated and compared. RESULTS: The vessel was unshielded by a rib according to CT in 114 of the 133 positions. The sensitivity, specificity and negative predictive value of portable US to image the vessel, when it was within the intercostal space on CT, was 0.86, 0.30 and 0.27 respectively. The performance of a high-end machine was not significantly different. The median time required for a pulmonologist to locate the vessel was 42 s and 18 s for the portable and high-end US respectively. CONCLUSIONS: US can be used to screen for a vulnerable vessel prior to pleural procedures, in a time amenable to use in clinical practice. Further, it is achievable by a pulmonologist using a portable US machine. If thoracentesis or chest tube insertion is being performed on a patient at increased risk of bleeding, screening for a vulnerable vessel with US prior to beginning the procedure is recommended.