Accuracy of a deep learning-based algorithm for the detection of thoracic aortic calcifications in chest computed tomography and cardiovascular surgery planning.

OBJECTIVES: To assess the accuracy of a deep learning-based algorithm for fully automated detection of thoracic aortic calcifications in chest computed tomography (CT) with a focus on the aortic clamping zone. METHODS: We retrospectively included 100 chest CT scans from 91 patients who were examined on second- or third-generation dual-source scanners. Subsamples comprised 47 scans with an electrocardiogram-gated aortic angiography and 53 unenhanced scans. A deep learning model performed aortic landmark detection and aorta segmentation to derive 8 vessel segments. Associated calcifications were detected and their volumes measured using a mean-based density thresholding. Algorithm parameters (calcium cluster size threshold, aortic mask dilatation) were varied to determine optimal performance for the upper ascending aorta that encompasses the aortic clamping zone. A binary visual rating served as a reference. Standard estimates of diagnostic accuracy and inter-rater agreement using Cohen's Kappa were calculated. RESULTS: Thoracic aortic calcifications were observed in 74% of patients with a prevalence of 27-70% by aorta segment. Using different parameter combinations, the algorithm provided binary ratings for all scans and segments. The best performing parameter combination for the presence of calcifications in the aortic clamping zone yielded a sensitivity of 93% and a specificity of 82%, with an area under the receiver operating characteristic curve of 0.874. Using these parameters, the inter-rater agreement ranged from κ 0.66 to 0.92 per segment. CONCLUSIONS: Fully automated segmental detection of thoracic aortic calcifications in chest CT performs with high accuracy. This includes the critical preoperative assessment of the aortic clamping zone.

Routine preoperative screening computed tomography of the thorax for cardiac surgery.

Introduction: This study aimed to evaluate the role of screening computed tomography (CT) of the thorax in cardiac surgery by analysing the presence of CT aortic calcifications in association with changes in operative strategy and postoperative stroke, and the CT features of emphysema with development of pneumonia. Methods: All patients who underwent cardiac surgery from January 2013 to October 2017 by a single surgeon were retrospectively studied. Patients who underwent screening CT thorax before cardiac surgery (CT group) were compared to those who did not (no CT group). Multivariate subgroup analyses were performed to determine significant association with postoperative outcomes. Results: A total of 392 patients were included, of which 156 patients underwent preoperative screening CT thorax. Patients in the CT group were older (63.9 vs. 59.0 years, P = 0.001), had fewer recent myocardial infarctions preoperatively (41% vs. 56.4%, P = 0.003) and had better ejection fraction (>30%; P = 0.02). Operative strategy was changed in 4.3% of patients, and 4.9% of patients suffered stroke postoperatively. The presence of CT aortic calcifications was significantly associated with change in operative strategy (P = 0.016) but not with postoperative stroke (P = 0.33). Age was an independent risk factor for change in operative strategy among patients with CT thorax (P = 0.02). Multivariate age-adjusted analysis showed only palpable plaque to be significantly associated with change in operative strategy (P < 0.001). None of the patients with CT emphysema features developed pneumonia. Conclusion: The results of this study do not support routine use of preoperative screening CT thorax. Contrasted CT may be advisable in older patients and for other operative planning purposes.

Aortic Calcification Affects Noninvasive Estimates of Central Blood Pressure in Patients with Severe Chronic Kidney Disease.

BACKGROUND: Central blood pressure (BP) assessed noninvasively considerably underestimates true invasively measured aortic BP in chronic kidney disease (CKD) patients. The difference between the estimated and the true aortic BP increases with decreasing estimated glomerular filtration rates (eGFR). The present study investigated whether aortic calcification affects noninvasive estimates of central BP. METHODS: Twenty-four patients with CKD stage 4-5 undergoing coronary angiography and an aortic computed tomography scan were included (63% males, age [mean ± SD ] 53 ± 11 years, and eGFR 9 ± 5 mL/min/1.73 m2). Invasive aortic BP was measured through the angiography catheter, while non-invasive central BP was obtained using radial artery tonometry with a SphygmoCor® device. The Agatston calcium score (CS) in the aorta was quantified on CT scans using the CS on CT scans. RESULTS: The invasive aortic systolic BP (SBP) was 152 ± 23 mm Hg, while the estimated central SBP was 133 ± 20 mm Hg. Ten patients had a CS of 0 in the aorta, while 14 patients had a CS >0 in the aorta. The estimated central SBP was lower than the invasive aortic SBP in patients with aortic calcification compared to patients without (mean difference 8 mm Hg, 95% CI 0.3-16; p = 0.04). The brachial SBP was lower than the aortic SBP in patients with aortic calcification compared to patients without (mean difference 10 mm Hg, 95% CI 2-19; p = 0.02). CONCLUSION: In patients with advanced CKD the presence of aortic calcification is associated with a higher difference between invasively measured central aortic BP and non-invasive estimates of central BP as compared to patients without calcifications.

A case of a 15-year evolution of a coral reef aortic lesion.

We are reporting here the 15-year history of a patient affected by a chronic and evolutive coral reef aorta successfully treated by repeated revascularization.

Effect of computed tomography before cardiac surgery on surgical strategy, mortality and stroke.

AIM: To investigate whether preoperative chest computed tomography (CT) decreases postoperative mortality and stroke rate in cardiac surgery by detection of calcifications and visualization of postoperative anatomy in redo cardiac surgery which can be used to optimize the surgical approach. METHODS: The PubMed, EMBASE and Cochrane databases were searched and articles concerning preoperative CT in cardiac surgery were included. Articles not reporting mortality, stroke rate or change in surgical approach were excluded. Studies concerning primary cardiac surgery as well as articles concerning redo cardiac surgery were both included. RESULTS: Eighteen studies were included (n=4057 patients) in which 2584 patients received a preoperative CT. Seven articles (n=1754 patients) concerned primary surgery and eleven articles (n=2303 patients) concerned redo cardiac surgery. None of the studies was randomized but 8 studies provided a comparison to a control group. Stroke rate decreased with 77-96% (primary surgery) and 18-100% (redo surgery) in patients receiving a preoperative CT. Mortality decreased up to 66% in studies investigating primary surgery while the effect on mortality in redo surgery varied widely. Change in surgical approach based on CT-findings consisted of choosing a different cannulation site, opting for off-pump surgery and cancellation of surgery. CONCLUSIONS: Current evidence suggests that preoperative CT imaging may lead to decreased stroke and mortality rate in patients undergoing primary cardiac surgery by optimizing surgical approach. In patients undergoing redo cardiac surgery stroke rate is also decreased but the effect on mortality is unclear. However, evidence is weak and included studies were of moderate quality.

Ultra low-dose chest ct with iterative reconstructions as an alternative to conventional chest x-ray prior to heart surgery (CRICKET study): Rationale and design of a multicenter randomized trial.

BACKGROUND: Stroke after cardiac surgery is a severe complication with a persistently high incidence of 1.4 - 9.7%. Postoperative strokes are mainly embolic and can be provoked by manipulation and clamping of the aorta during cardiac surgery, resulting in the mobilization of atherothrombotic material and calcifications from the aortic wall. Computed tomography (CT) can offer preoperative visualization of aortic calcifications with low radiation exposure. We hypothesize that preoperative knowledge regarding the location and extent of aortic calcifications can be used to optimize surgical strategy and decrease postoperative stroke rate. METHODS/DESIGN: The CRICKET study (ultra low-dose chest CT with iterative reconstructions as an alternative to conventional chest x-ray prior to heart surgery) is a prospective multicenter randomized clinical trial to evaluate whether non-contrast chest CT before cardiac surgery can decrease postoperative stroke rate by optimizing surgical strategy. Patients scheduled to undergo cardiac surgery aged 18 years and older are eligible for inclusion. Exclusion criteria are pregnancy, a chest/cardiac CT in the past three months, emergency surgery, concomitant or prior participation in a study with ionizing radiation and unwillingness to be informed about incidental findings. Subjects (n = 1.724) are randomized between routine care, including a chest x-ray, or routine care with an additional low dose chest CT. The primary objective is to investigate whether the postoperative in-hospital stroke rate is reduced in the CT arm compared to the routine care arm of the randomized trial. The secondary outcome measures are altered surgical approach based on CT findings and cost-effectiveness.

Association of lumbar fractures, abdominal aortic calcification, and osteopenia.

PURPOSE: The purpose was to assess if abdominal aortic calcification (AAC) and low bone mineral density (BMD) are associated with fractures on lumbar spine radiographs in trauma patients. METHODS: Retrospectively, 303 consecutive lumbar radiographs were independently reviewed by two radiologists for AAC, low BMD, and traumatic findings. RESULTS: Thirty-one percent of patients had low BMD, 34% had AAC, and 24% had both. Eleven percent of radiographs showed traumatic findings. Seventy-six percent of positive cases had low BMD (P<.001), and 64% had AAC (P<.001). CONCLUSION: A higher index of suspicion for fractures is warranted when AAC and low BMD are present.