Reduction of missed thoracic findings in emergency whole-body computed tomography using artificial intelligence assistance.

BACKGROUND: Radiology reporting of emergency whole-body computed tomography (CT) scans is time-critical and therefore involves a significant risk of pathology under-detection. We hypothesize a relevant number of initially missed secondary thoracic findings that would have been detected by an artificial intelligence (AI) software platform including several pathology-specific AI algorithms. METHODS: This retrospective proof-of-concept-study consecutively included 105 shock-room whole-body CT scans. Image data was analyzed by platform-bundled AI-algorithms, findings were reviewed by radiology experts and compared with the original radiologist's reports. We focused on secondary thoracic findings, such as cardiomegaly, coronary artery plaques, lung lesions, aortic aneurysms and vertebral fractures. RESULTS: We identified a relevant number of initially missed findings, with their quantification based on 105 analyzed CT scans as follows: up to 25 patients (23.8%) with cardiomegaly or borderline heart size, 17 patients (16.2%) with coronary plaques, 34 patients (32.4%) with aortic ectasia, 2 patients (1.9%) with lung lesions classified as "recommended to control" and 13 initially missed vertebral fractures (two with an acute traumatic origin). A high number of false positive or non-relevant AI-based findings remain problematic especially regarding lung lesions and vertebral fractures. CONCLUSIONS: We consider AI to be a promising approach to reduce the number of missed findings in clinical settings with a necessary time-critical radiological reporting. Nevertheless, algorithm improvement is necessary focusing on a reduction of "false positive" findings and on algorithm features assessing the finding relevance, e.g., fracture age or lung lesion malignancy.

Macrophage ablation significantly reduces uptake of imaging probe into organs of the reticuloendothelial system.

BACKGROUND: Macrophages engulf particulate contrast media, which is pivotal for biomedical imaging. PURPOSE: To introduce a macrophage ablation animal model by showing its power to manipulate the kinetics of imaging probes. MATERIAL AND METHODS: The kinetics of a particulate computed tomography (CT) contrast media was compared in macrophage ablative mice and normal mice. Liposomes (size 220 µg), loaded with clodronate, were injected into the peritoneum of three C57BL/6 mice. On the third day, 200 µL of the particulate agent ExiTron nano 6000 were injected into three macrophage-ablative mice and three control mice. CT scans were acquired before and 3 min, 1 h, 6 h, and 24 h after the ExiTron application. The animals were sacrificed, and their spleens and livers removed. Relative CT values (CTV) were measured and analyzed. RESULTS: Liver and spleen enhancement of treated mice and controls were increasing over time. The median peak values were different with 225 CTV for treated mice and 582 CTV for controls in the liver (P = 0.032) and 431 CTV for treated and 974 CTV in controls in the spleen (P = 0.016). CONCLUSION: Macrophage ablation leads to a decrease of enhancement in organs containing high numbers of macrophages, but only marginal changes in macrophage-poor organs. Macrophage ablation can influence the phagocytic activity and thus opens new potentials to investigate and manipulate the uptake of imaging probes.

Structured Reporting of CT Angiography Runoff Examinations of the Lower Extremities.

OBJECTIVES: The aim was to evaluate the effect of structured reporting of computed tomography angiography (CTA) runoff studies on clarity, completeness, clinical relevance, usefulness of the radiology reports, further testing, and therapy in patients with known or suspected peripheral arterial disease. METHODS: Conventional reports (CRs) and structured reports (SRs) were generated for 52 patients who had been examined with a CTA runoff examination of the lower extremities. The sample size was based on power calculations with a power of 95% and a significance level of .007 (adjusted for multiple testing). CRs were dictated in a free text form; SRs contained a consistent ordering of observations with standardised subheadings. CRs were compared with SRs. Two vascular medicine specialists and two vascular surgeons rated the reports regarding their satisfaction with clarity, completeness, clinical relevance, and usefulness as well as overall satisfaction. Additionally, they made hypothetical decisions on further testing and therapy. Median ratings were compared using the Wilcoxon signed rank test and generalised linear mixed effects models. RESULTS: SRs received higher ratings for satisfaction with clarity (median rating 9.0 vs. 7.0, p < .0001) and completeness (median rating 9.0 vs. 7.5, p < .0001) and were judged to be of greater clinical relevance (median rating 9.0 vs. 8.0, p < .0001) and usefulness (median rating 9.0 vs. 8.0, p < .0001). Overall satisfaction was also higher for SRs (median rating 9.0 vs. 7.0, p < .0001) than CRs. There were no significant differences in further testing or therapy. CONCLUSION: Referring clinicians perceive SRs of CTA runoff examinations of the lower extremities as offering superior clarity, completeness, clinical relevance, and usefulness than CRs. Structured reporting does not appear to alter further testing or therapy in patients with known or suspected peripheral arterial disease.

Early Imaging Prediction of Malignant Cerebellar Edema Development in Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Malignant cerebellar edema (MCE) is a life-threatening complication of acute ischemic stroke that requires timely diagnosis and management. Aim of this study was to identify imaging predictors in initial multiparametric computed tomography (CT), including whole-brain CT perfusion (WB-CTP). METHODS: We consecutively selected all subjects with cerebellar ischemic WB-CTP deficits and follow-up-confirmed cerebellar infarction from an initial cohort of 2635 patients who had undergone multiparametric CT because of suspected stroke. Follow-up imaging was assessed for the presence of MCE, measured using an established 10-point scale, of which scores ≥4 are considered malignant. Posterior circulation-Acute Stroke Prognosis Early CT Score (pc-ASPECTS) was determined to assess ischemic changes on noncontrast CT, CT angiography (CTA), and parametric WB-CTP maps (cerebellar blood flow [CBF]; cerebellar blood volume; mean transit time; time to drain). Fisher's exact tests, Mann-Whitney U tests, and receiver operating characteristics analyses were performed for statistical analyses. RESULTS: Out of a total of 51 patients who matched the inclusion criteria, 42 patients (82.4%) were categorized as MCE- and 9 (17.6%) as MCE+. MCE+ patients had larger CBF, cerebellar blood volume, mean transit time, and time to drain deficit volumes (all with P<0.001) and showed significantly lower median pc-ASPECTS assessed using WB-CTP (CBF, cerebellar blood volume, mean transit time, time to drain; all with P<0.001) compared with MCE- patients, while median pc-ASPECTS on noncontrast CT and CTA was not significantly different (both P>0.05). Receiver operating characteristics analyses yielded the largest area under the curve values for the prediction of MCE development for CBF (0.979) and cerebellar blood volume deficit volumes (0.956) and pc-ASPECTS on CBF (0.935), whereas pc-ASPECTS on noncontrast CT (0.648) and CTA (0.684) had less diagnostic value. The optimal cutoff value for CBF deficit volume was 22 mL, yielding 100% sensitivity and 90% specificity for MCE classification. CONCLUSIONS: WB-CTP provides added diagnostic value for the early identification of patients at risk for MCE development in acute cerebellar stroke.