Uncertainty quantification in computed tomography pulmonary angiography.

Computed tomography (CT) imaging of the thorax is widely used for the detection and monitoring of pulmonary embolism (PE). However, CT images can contain artifacts due to the acquisition or the processes involved in image reconstruction. Radiologists often have to distinguish between such artifacts and actual PEs. We provide a proof of concept in the form of a scalable hypothesis testing method for CT, to enable quantifying uncertainty of possible PEs. In particular, we introduce a Bayesian Framework to quantify the uncertainty of an observed compact structure that can be identified as a PE. We assess the ability of the method to operate under high-noise environments and with insufficient data.

Non-pharmacological interventions for the treatment of post-stroke fatigue: A systematic review.

BACKGROUND: Post-stroke fatigue (PSF) affects 50% of stroke survivors. Current guidance on management of this condition is limited. AIMS: This systematic review and meta-analysis aimed to identify and analyze all randomized clinical trials (RCTs) of non-pharmacological interventions for the treatment of PSF. SUMMARY OF REVIEW: Six electronic databases were searched from inception to January 2023 for English-language RCTs investigating the efficacy of non-pharmacological interventions versus passive controls in patients with PSF. The primary outcome was fatigue severity at the end of the intervention. The Cochrane risk-of-bias (ROB)2 tool was used to assess evidence quality. A total of 7990 records were retrieved, 333 studies were scrutinized, and 13 completed RCTs (484 participants) were included. Interventions included psychological therapies, physical therapies, and brain stimulation. Nine studies provided sufficient data for meta-analysis, of which seven also had follow-up data. Fatigue severity was lower in the intervention groups at the end of the intervention compared with control (participants = 310, standardized mean difference (SMD) = -0.57, 95% confidence intervals (CIs) (-0.87 to -0.28)) and at follow-up (participants = 112, SMD = -0.36, 95% CIs (-0.83 to 0.10)). Certainty in the effect estimate was downgraded to low for a serious ROB and imprecision. Subgroup analysis revealed significant benefits with physical therapy and brain stimulation but not psychological therapies, though sample sizes were low. CONCLUSION: Non-pharmacological interventions improved fatigue but the quality of evidence was low. Further RCTs are needed for PSF management.

The Effect of Oral Laxatives on Rectal Distension and Image Quality in Magnetic Resonance Imaging of the Prostate.

Introduction Increasing rectal size is associated with increased artefacts on magnetic resonance imaging (MRI) of the prostate and has the potential to degrade image quality. The objective of this study was to analyse the effect of oral laxative medication on rectal distension and image quality in prostate MRI. Methods Eighty patients prospectively received either 15 mg of oral senna (laxative group) or no medication (control group). Patients underwent prostate MRI according to standard local protocol and seven rectal dimensions on axial and sagittal images were measured. A subjective assessment of rectal distension was also made using a five-point Likert scale. Finally, artefacts on diffusion-weighted sequences were assessed using a four-point Likert scale. Results There was a small reduction in rectal diameter on sagittal images in the laxative group compared to the control group, with mean diameters of 27.1 mm and 30.0 mm respectively, p=0.02. There was no significant difference in rectal measurements of anteroposterior diameter, transverse diameter, or rectal circumference on axial imaging. Subjective scoring also demonstrated no significant difference in diffusion-weighted imaging quality between the laxative group and control group, p=0.82. Conclusion Bowel preparation with the oral laxative, senna, provided only a marginal decrease in rectal distension on one measure and no reduction in artefacts on diffusion-weighted sequences. The findings of this study do not support the routine use of this medication in patients undergoing prostate MRI.

Whole-body single photon emission computed tomography/computed tomography for assessment of oncological bone disease - is an extended field of view (from vertex to toes) of clinical value?

OBJECTIVES: Whole-body single photon emission computed tomography/computed tomography (WB-SPECT/CT) is useful for diagnosing bone metastases. When performed on a dual-headed gamma camera, this may cover from clavicles to proximal femurs due to time constraints. In contrast, the novel 360 o cadmium-zinc-telluride scanner can perform WB-SPECT/CT (from vertex to toes) in approximately 20 min. The aim was to assess the prevalence of additional findings above the clavicles and below the lesser trochanters and the prevalence of incidental findings in the CT component. METHODS: Retrospective study of 117 WB-SPECT/CT scans for oncological bone assessment over a 4-month-period. Scan analysis was performed by two independent experienced radionuclide radiologists. RESULTS: The male:female ratio was 71:46 and the mean patient age was 68 years. The primary malignancies were predominantly prostate 65/117 (55.6%) and breast 40/117 (34.2%). There were additional findings of malignancy above the clavicles in 16/116 scans (13.8%) and below the lesser trochanters in 16/117 scans (13.7%). Two cases in the 'above the clavicles' group were suspected solitary metastases, whereas four cases in the 'below lesser trochanters' group were bone metastases at risk of pathological fracture. Incidental findings of clinical significance included suspected new malignancy in 11/117 (9.4%). CONCLUSION: A WB-SPECT/CT (from vertex to toes) oncological bone protocol is useful for the detection of additional findings of clinical significance above the clavicles and below the lesser trochanters. Reviewing and reporting the CT findings in SPECT/CT is important.

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.

Comparing the patient experience between a novel 360° gamma camera (VERITON-CT) and a conventional dual head gamma camera.

Aims: To explore whether the novel 360° gamma camera design of VERITON-CT adversely affects the rate of scan non-completion due to claustrophobia or other patient experience factors, when compared to a standard dual-headed gamma camera. Methods: Single centre prospective study of all nuclear medicine studies on either of two gamma cameras; the VERITON-CT (Spectrum Dynamics Medical) and Discovery NM/CT 670 (GE Healthcare). It was recorded whether the patient had completed the scan as protocoled or, due to claustrophobia, had a shortened scan or no scan. The patients were also offered a patient experience questionnaire, with domains of comfort, scan time, scan noise and claustrophobia assessed using a five-point Likert scale. Results: Over a four-month period, there were 296 patients scanned on the Discovery scanner and 274 patients scanned on the VERITON-CT scanner. There was a scan non-completion rate, due to claustrophobia, of 1.35 % for the Discovery and 1.46 % for the VERITON-CT scanner. 354/570 (62%) of all patients involved returned their questionnaires. There was no statistical difference between the responses for comfort, scan time, scan noise and feelings of claustrophobia. Conclusion: The study provides evidence that the novel 360° gamma camera design of VERITON-CT does not lead to a significantly increased scan failure rate due to claustrophobia and there is no change in the subjective experience for patients.