Artificial intelligence can detect left ventricular dilatation on contrast-enhanced thoracic computer tomography relative to cardiac magnetic resonance imaging.

OBJECTIVES: To assess the diagnostic accuracy of an automated algorithm to detect left ventricular (LV) dilatation on non-ECG gated CT, using cardiac magnetic resonance (CMR) as reference standard. METHODS: Consecutive patients with contrast-enhanced CT thorax and CMR within 31 days (2016-2020) were analysed (n = 84). LV dilatation was defined against age-, sex- and body surface area-specific values for CMR. CTs underwent automated artificial intelligence(AI)-derived analysis that segmented ventricular chambers, presenting maximal LV diameter and volume. Area under the receiver operator curve (AUC-ROC) analysis identified CT thresholds with ≥90% sensitivity and highest specificity and ≥90% specificity with highest sensitivity. Youden's Index was used to identify thresholds with optimised sensitivity and specificity. RESULTS: Automated diameter analysis was feasible in 92% of cases (77/84; 45 men, age 61 ± 14 years, mean CT to CMR interval 10 ± 8 days). Relative to CMR as a reference standard, 45% had LV dilatation. In males, an automated LV diameter measurement of ≥55.5 mm was ≥90% specific for CMR-defined LV dilatation (positive predictive value (PPV) 85.7%, negative predictive value (NPV) 61.2%, accuracy 68.9%). In females, an LV diameter of ≥49.7 mm was ≥90% specific for CMR-defined LV dilatation (PPV 66.7%, NPV 73.1%, accuracy 71.9%). AI CT volumetry data did not significantly improve AUC performance. CONCLUSION: Fully automated AI-derived analysis LV dilatation on routine unselected non-gated contrast-enhanced CT thorax studies is feasible. We have defined thresholds for the detection of LV dilatation on CT relative to CMR, which could be used to routinely screen for dilated cardiomyopathy at the time of CT. ADVANCES IN KNOWLEDGE: We show, for the first time, that a fully-automated AI-derived analysis of maximal LV chamber axial diameter on non-ECG-gated thoracic CT is feasible in unselected real-world cases and that the derived measures can predict LV dilatation relative to cardiac magnetic resonance imaging, the non-invasive reference standard for determining cardiac chamber size. We have derived sex-specific cut-off values to screen for LV dilatation on routine contrast-enhanced thoracic CT. Future work should validate these thresholds and determine if technology can alter clinical outcomes in a cost-effective manner.

Subacute combined degeneration of the cord secondary to nitrous oxide misuse: No laughing matter.

Nitrous oxide (N2O) has several traditional uses as a surgical and dental anaesthetic, as well as in aerosol spray propellants. It is the combination of analgesic and euphoric qualities coupled with accessibility as an over-the-counter household item that lends N2O to recreational use. Despite increasing evidence that prolonged use of N2O both medically and as a drug of abuse can cause disabling neurological side-effects, it remains widely used. We present the case of an 18-year-old male who was diagnosed with subacute combined degeneration of the cord (SCDC) secondary to acute, heavy recreational use of N2O. The patient presented with progressive paraesthesia affecting his hands and feet associated with distal weakness. MRI of the cervical spine revealed symmetric bilateral high T2 signal within the dorsal columns extending from the level of C2 to T2 with the inverted 'V' sign on axial T 2-weighted slices indicative of SCDC. Although vitamin B12 levels were within normal range, marked elevation of methylmalonic acid and homocysteine support the diagnosis of B12 inactivation and functional B12 deficiency, which fully resolved with treatment.

18FDG-PET/CT findings in COVID-19: a single centre retrospective radiological review.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the infectious disease COVID-19, was declared a global pandemic in March 2020. As radiology departments recommence 18FDG-PET/CT imaging, it is likely that both asymptomatic and specific symptomatic patients with COVID-19 infection will be imaged, particularly if the disease becomes endemic in the UK. We review the clinical scenarios where 18FDG-PET/CT could be performed in COVID-19 positive patients. Our local protocol for safely scanning known COVID-19 positive patients is described, highlighting considerations for other departments. We present the findings from a series of known COVID-19 positive patients and two further asymptomatic cases evaluated with18FDG-PET/CT. Classic, indeterminate, normal and non-COVID-19 manifestations on both the 18FDG-PETand low dose CT component are described as an aid for radiologists and nuclear medicine physicians when reporting 18FDG PET/CT.