The Utility of Deformable Image Registration for Small Artery Visualisation in Contrast-Enhanced Whole Body MR Angiography

Purpose; An investigation was carried out into the effect of three image registration techniques on the diagnostic image quality of contrast-enhanced magnetic resonance angiography (CE-MRA) images. Methods Whole-body CE-MRA data from the lower legs of 27 patients recruited onto a study of asymptomatic atherosclerosis were processed using three deformable image registration algorithms. The resultant diagnostic image quality was evaluated qualitatively in a clinical evaluation by four expert observers, and quantitatively by measuring contrast-to-noise ratios and volumes of blood vessels, and assessing the techniques’ ability to correct for varying degrees of motion. Results The first registration algorithm (‘AIR’) introduced significant stenosis-mimicking artefacts into the blood vessels’ appearance, observed both qualitatively (clinical evaluation) and quantitatively (vessel volume measurements). The other two algorithms (‘Slicer’ and ‘SEMI’) based on the normalised mutual information (NMI) concept and designed specifically to deal with variations in signal intensity as found in contrast-enhanced image data, did not suffer from this serious issue but were rather found to significantly improve the diagnostic image quality both qualitatively and quantitatively, and demonstrated a significantly improved ability to deal with the common problem of patient motion. Conclusions This work highlights both the significant benefits to be gained through the use of suitable registration algorithms and the deleterious effects of an inappropriate choice of algorithm for contrast-enhanced MRI data. The maximum benefit was found in the lower legs, where the small arterial vessel diameters and propensity for leg movement during image acquisitions posed considerable problems in making accurate diagnoses from the un-registered images

Variation in Urgent Imaging Requests for Stroke during the Covid-19 pandemic. Review of a National Dataset

Introduction. The Covid-19 pandemic has been associated with a reduction in the number of Emergency presentations with acute stroke. Ireland operates a National Integrated Medical Imaging System (NIMIS) and has implemented a single order package, FAST CT, for suspected stroke incorporating non-contrast CT, multiphase cerebral angiography and CT perfusion. We examined the frequency of requests made during the pandemic to assess national changes in emergency stroke activity. Methods. Data were obtained from NIMIS as to numbers of CT FAST sequences performed per day from 1st December 2019 to 30th June 2020. Four periods were analysed; baseline (1st December 2019-29th February 2020), first case to lockdown (1st -24th March 2020), lockdown to first easing of restrictions (25th March-17th May) and gradual removal of lockdown restrictions (18th May -30th June). Data were compared to number of daily reported Covid-19 cases. Results. Data for 1849 individuals were assessed. An average of 9.32 (SD 1.40) daily urgent scans were performed during baseline. This fell 9.3% to 8.45 (SD 1.42) between 1st case and lockdown (p=0.06, t-test). During Lockdown the rate fell to 8.03/day (SD 2.71), a 13.8% reduction on baseline. During relaxation of lockdown numbers increased to 8.80/day (SD 3.44). The worst 7-day period was leading up to lockdown where numbers fell by 41.7%. Conclusion. Number of scans requested declined by a modest but statistically significant level over the period of the pandemic and lockdown. They began to recover as lockdown was eased. The maximal decline corresponded with the period immediately before lockdown

Pattern of Investigation Reflects Risk Profile in Emergency Medical Admissions

Demand for hospital resources may increase over time; we have examined all emergency admissions (51,136 episodes) from 2005 to 2013 for underlying trends and whether resource utilization and clinical risk are correlated. We used logistic regression of the resource indicator against 30-day in-hospital mortality and adjusted this risk estimate for other outcome predictors. Generally, resource indicators predicted an increased risk of a 30-day in-hospital death. For CT Brain the Odds Ratio (OR) was 1.37 (95% CI: 1.27, 1.50), CT Abdomen 3.48 (95% CI: 3.02, 4.02) and CT Chest, Thorax, Abdomen and Pelvis 2.50 (95% CI: 2.10, 2.97). Services allied to medicine including Physiotherapy 2.57 (95% CI: 2.35, 2.81), Dietetics 2.53 (95% CI: 2.27, 2.82), Speech and Language 5.29 (95% CI: 4.57, 6.05), Occupational Therapy 2.65 (95% CI: 2.38, 2.94) and Social Work 1.65 (95% CI: 1.48, 1.83) all predicted an increased risk. The in-hospital 30-day mortality increased with resource utilization, from 4.7% (none) to 27.0% (five resources). In acute medical illness, the use of radiological investigations and allied professionals increased over time. Resource utilization was calibrated from case complexity/30-day in-hospital mortality suggesting that complexity determined the need for and validated the use of these resources

CT coronary angiography and COVID-19: inpatient use in acute chest pain service

Objectives CT coronary angiography (CTCA) is a well-validated clinical tool in the evaluation of chest pain. In our institution, CTCA availability was increased in January 2020, and subsequently, expanded further to replace all exercise testing during the COVID-19 pandemic. Our objective was to assess the impact of increased utilisation of CTCA on length of stay in patients presenting with chest pain in the prepandemic era and during the COVID-19 pandemic.Methods Study design was retrospective. Patients referred for cardiology review between October 2019 and May 2020 with chest pain and/or dyspnoea were broken into three cohorts: a baseline cohort, a cohort with increased CTCA availability and a cohort with increased CTCA availability, but after the national lockdown due to COVID-19. Coronary angiography and revascularisation, length of stay and 30-day adverse outcomes were assessed.Results 513 patients (35.3% female) presented over cohorts 1 (n=179), 2 (n=182), and 3 (n=153). CTCA use increased from 7.8% overall in cohort 1% to 20.4% in cohort 3. Overall length of stay for the patients undergoing CTCA decreased from a median of 4.2 days in cohort 1 to 2.5 days in cohort 3, with no increase in 30 days adverse outcomes. Invasive coronary angiogram rates were 45.8%, 39% and 34.2% across the cohorts. 29.6% underwent revascularisation in cohort 1, 15.9% in cohort 2 and to 16.4% in cohort 3.Conclusions Increased CTCA availability was associated with a significantly reduced length of stay both pre-COVID-19 and post-COVID-19 lockdown, without any increase in 30-day adverse outcomes

Neoadjuvant crizotinib in advanced inflammatory myofibroblastic tumour with ALK gene rearrangement

Background Inflammatory myofibroblastic tumours (IMTs) are rare sarcomas that were first described in the lung. They are composed of myofibroblastic mesenchymal spindle cells accompanied by an inflammatory infiltrate of plasma cells. Complete resection is the treatment of choice. There is currently no standard treatment for inoperable or recurrent disease. Expression of ALK protein triggered by ALK gene rearrangement at chromosome 2p23 has been found in 36%-60% of IMTs. Case report We report a rapid early response to crizotinib as neoadjuvant therapy, enabling surgical excision of a large ALK-translocated IMT, which resulted in complete disease clearance. To the best of our knowledge, this is the first case in the literature of a patient with IMT in whom crizotinib was used successfully in the neoadjuvant or curative setting