HIV, HIV-specific Factors and Myocardial Disease in Women.

BACKGROUND: People with HIV (PWH) have an increased risk of cardiovascular disease (CVD). Cardiac magnetic resonance (CMR) has documented higher myocardial fibrosis, inflammation and steatosis in PWH, but studies have mostly relied on healthy volunteers as comparators and focused on men. METHODS: We investigated the associations of HIV and HIV-specific factors with CMR phenotypes in female participants enrolled in the Women's Interagency HIV Study's New York and San Francisco sites. Primary phenotypes included myocardial native (n) T1 (fibro-inflammation), extracellular volume fraction (ECV, fibrosis) and triglyceride content (steatosis). Associations were evaluated with multivariable linear regression, and results pooled or meta-analyzed across centers. RESULTS: Among 261 women with HIV (WWH, total n = 362), 76.2% had undetectable viremia at CMR. For the 82.8% receiving continuous antiretroviral therapy (ART) in the preceding 5 years, adherence was 51.7%, and 71.3% failed to achieve persistent viral suppression (42.2% with peak viral load < 200 cp/mL). Overall, WWH showed higher nT1 than women without HIV (WWOH) after full adjustment. This higher nT1 was more pronounced in those with antecedent or current viremia or nadir CD4+ count < 200 cells/µL, the latter also associated with higher ECV. WWH and current CD4+ count < 200 cells/µL had less cardiomyocyte steatosis. Cumulative exposure to specific ART showed no associations. CONCLUSIONS: Compared with sociodemographically similar WWOH, WWH on ART exhibit higher myocardial fibro-inflammation, which is more prominent with unsuppressed viremia or CD4+ lymphopenia. These findings support the importance of improved ART adherence strategies, along with better understanding of latent infection, to mitigate cardiac end-organ damage in this population.

Deep learning of longitudinal chest X-ray and clinical variables predicts duration on ventilator and mortality in COVID-19 patients.

OBJECTIVES: To use deep learning of serial portable chest X-ray (pCXR) and clinical variables to predict mortality and duration on invasive mechanical ventilation (IMV) for Coronavirus disease 2019 (COVID-19) patients. METHODS: This is a retrospective study. Serial pCXR and serial clinical variables were analyzed for data from day 1, day 5, day 1-3, day 3-5, or day 1-5 on IMV (110 IMV survivors and 76 IMV non-survivors). The outcome variables were duration on IMV and mortality. With fivefold cross-validation, the performance of the proposed deep learning system was evaluated by receiver operating characteristic (ROC) analysis and correlation analysis. RESULTS: Predictive models using 5-consecutive-day data outperformed those using 3-consecutive-day and 1-day data. Prediction using data closer to the outcome was generally better (i.e., day 5 data performed better than day 1 data, and day 3-5 data performed better than day 1-3 data). Prediction performance was generally better for the combined pCXR and non-imaging clinical data than either alone. The combined pCXR and non-imaging data of 5 consecutive days predicted mortality with an accuracy of 85 ± 3.5% (95% confidence interval (CI)) and an area under the curve (AUC) of 0.87 ± 0.05 (95% CI) and predicted the duration needed to be on IMV to within 2.56 ± 0.21 (95% CI) days on the validation dataset. CONCLUSIONS: Deep learning of longitudinal pCXR and clinical data have the potential to accurately predict mortality and duration on IMV in COVID-19 patients. Longitudinal pCXR could have prognostic value if these findings can be validated in a large, multi-institutional cohort.

Epidemiology, Risk Factors and Outcomes of Pneumomediastinum in Patients with Coronavirus Disease 2019: A Case-Control Study.

Background: Since the beginning of the ongoing Coronavirus Disease 2019 (COVID-19) pandemic, pneumomediastinum has been reported in patients with COVID-19 pneumonia and acute respiratory distress syndrome. It has been suggested that pneumomediastinum may portend a worse outcome in such patients although no investigation has established this association definitively. Research Question: We hypothesized that the finding of pneumomediastinum in the setting of COVID-19 disease may be associated with a worse clinical outcome. The purpose of this study was to determine if the presence of pneumomediastinum was predictive of increased mortality in patients with COVID-19. Study Design and Methods: A retrospective case-control study utilizing clinical data and imaging for COVID-19 patients seen at our institution from 3/7/2020 to 5/20/2020 was performed. 87 COVID-19 positive patients with pneumomediastinum were compared to 87 COVID-19 positive patients without pneumomediastinum and to a historical group of patients with pneumomediastinum during the same time frame in 2019. Results: The incidence of pneumomediastinum was increased more than 6-fold during the COVID-19 pandemic compared to 2019 (P = <.001). 1.5% of all COVID-19 patients and 11% of mechanically ventilated COVID-19 patients at our institution developed pneumomediastinum. Patients who developed pneumomediastinum had a significantly higher PEEP and lower P/F ratio than those who did not (P = .002 and .033, respectively). Pneumomediastinum was not found to be associated with increased mortality (P = .16, confidence interval [CI]: 0.89-2.09, 1.37). The presence of concurrent pneumothorax at the time of pneumomediastinum diagnosis was associated with increased mortality (P = .013 CI: 1.15-3.17, 1.91). Conclusion: Pneumomediastinum is not independently associated with a worse clinical prognosis in COVID-19 positive patients. The presence of concurrent pneumothorax was associated with increased mortality.

Prone Chest Radiographs: Distinguishing Features and Identification of Support Devices.

PURPOSE: Prone position is known to improve acute lung injury, and chest radiographs are often necessary to monitor disease and confirm support device placement. However, there is a paucity of literature regarding radiographs obtained in this position. We evaluated prone radiographs for distinguishing features and ability to identify support devices. METHODS: Pairs of prone and supine radiographs obtained during the COVID-19 pandemic were assessed retrospectively. IRB approval and waiver of informed consent were obtained. Radiographs were assessed for imaging adequacy, distinguishing features, and support device identification (endotracheal tube, enteric tube, or central line). Radiographs were reviewed by ≥ 2 cardiothoracic radiologists. RESULTS: Radiographs from 81 patients (63yo ± 13, 30% women) were reviewed. Prone and supine radiographs were comparable for imaging the lung bases (81% vs. 90%, p = 0.35) and apices (93% vs. 94%, p = 1); prone radiographs more frequently had significant rotation (36% vs. 19%, p = 0.021). To identify prone technique, scapula tip located beyond the rib border was 89% sensitive (95%CI 80-95%) and 85% specific (76-92%), and a fundal stomach bubble was 44% sensitive (33-56%) and 90% specific (81-96%). For women, displaced breast shadow was 46% sensitive (26-67%) and 92% specific (73-99%). Prone and supine radiographs each identified > 99% of support devices. Prone exams trended toward increased rate of malpositioned device (12% vs. 6%, p = 0.07). CONCLUSION: Scapula position reliably distinguishes prone from supine position; fundal stomach bubble or displaced breast shadow is specific for prone position. Prone radiographs reliably identify line and tube position, which is particularly important as prone patients appear at increased risk for malpositioned devices.

A Retrospective Multi-Site Academic Center Analysis of Pneumothorax and Associated Risk Factors after CT-Guided Percutaneous Lung Biopsy.

PURPOSE: To assess the risk factors, incidence and significance of pneumothorax in patients undergoing CT-guided lung biopsy. METHODS: Patients who underwent a CT-guided lung biopsy between August 10, 2010 and September 19, 2016 were retrospectively identified. Imaging was assessed for immediate and delayed pneumothorax. Records were reviewed for presence of risk factors and the frequency of complications requiring chest tube placement. 604 patients were identified. Patients who underwent chest wall biopsy (39) or had incomplete data (9) were excluded. RESULTS: Of 556 patients (average age 66 years, 50.2% women) 26.3% (146/556) had an immediate pneumothorax and 2.7% (15/556) required chest tube placement. 297/410 patients without pneumothorax had a delayed chest X-ray. Pneumothorax developed in 1% (3/297); one patient required chest tube placement. Pneumothorax risk was associated with smaller lesion sizes (OR 0.998; 95% CI (0.997, 0.999); [p = 0.002]) and longer intrapulmonary needle traversal (OR 1.055; 95% CI (1.033, 1.077); [p < 0.001]). Previous ipsilateral lung surgery (OR 0.12; 95% CI (0.031, 0.468); [p = 0.002]) and longer needle traversal through subcutaneous tissue (OR 0.976; 95% CI (0.96, 0.992); [p = 0.0034]) were protective of pneumothorax. History of lung cancer, biopsy technique, and smoking history were not significantly associated with pneumothorax risk. CONCLUSION: Delayed pneumothorax after CT-guided lung biopsy is rare, developing in 1% of our cohort. Pneumothorax is associated with smaller lesion size and longer intrapulmonary needle traversal. Previous ipsilateral lung surgery and longer needle traversal through subcutaneous tissues are protective of pneumothorax. Stratifying patients based on pneumothorax risk may safely obviate standard post-biopsy delayed chest radiographs.

Thoracic aortic dissection classification among radiologists and surgeons and management trends.

OBJECTIVE: To investigate the discrepancy rate in classification of newly diagnosed aortic dissection (AD) between radiologists and surgeons and explore patient management. METHODS: 3255 CTs performed for AD from June 2013 to June 2018 at our institution were retrospectively identified. CT reports and charts were reviewed to identify newly diagnosed AD or intramural hematoma (IMH). Radiology reports and electronic health records were reviewed for Stanford type A or B classification and surgical versus medical management. RESULTS: Newly diagnosed AD was diagnosed in 1.9% (62/3255) with one false positive, mean age 60 years. Discrepancy rate was 1.6% (1/61). Type A AD/IMH was treated surgically in 85% (23/27), medically in 15% (4/27). Type B AD/IMH was treated surgically in 56% (19/34) (endovascular 95% (18/19)), medically in 44% (15/34). CONCLUSIONS: Discrepancy rate between radiologists and surgeons in Stanford classification of aortic dissection was low. Management of type B AD/IMH was predominantly endovascular, reflecting a shift in practice from the historical binary management strategy of type A dissections being treated surgically and type B dissections medically.

Clinical significance of incidental findings on coronary CT angiography: Insights from a randomized controlled trial.

BACKGROUND: The effect of incidental findings from coronary computed tomography angiography (CCTA) on management has not been rigorously investigated. This study uses a control group to explore this relationship. METHODS: Analysis of data from a randomized controlled trial of acute chest pain patients admitted to telemetry was performed. Patients were randomized to undergo either CCTA (n = 200) or radionuclide myocardial perfusion imaging (MPI) (n = 200). Incidental findings were determined from imaging reports. Records were reviewed to determine subsequent management and imaging during and after hospitalization. Comparisons were performed using Fischer's exact tests. RESULTS: 386 incidental findings were found among 187 CCTA studies. No extra-cardiac incidental findings were noted in the MPI arm, which served as an effective control group. There were significantly more non-coronary medical workups during admission in the CCTA group compared to the MPI group [20% (39) vs. 12% (23), P = 0.038]. CCTA patients underwent significantly more resting echocardiography during the inpatient workup compared to the MPI group [38% (75) vs. 18% (55), P = 0.042]. CCTA patients underwent significantly more non-contrast chest CT exams in the year following admission compared to MPI patients [14% (27) vs. 7% (13) P = 0.029]. CONCLUSIONS: Incidental findings on inpatient CCTAs performed for chest pain have a significant impact on treatment and imaging during and following hospital admission.

Ventricular Myocardial Fat: An Unexpected Biomarker for Long-term Survival?

PURPOSE: To examine the association between myocardial fat, a poorly understood finding frequently observed on non-contrast CT, and all-cause mortality in patients with and without a history of prior MI. MATERIALS AND METHODS: A retrospective cohort from a diverse urban academic center was derived from chronic myocardial infarction (MI) patients (n = 265) and three age-matched patients without MI (n = 690) who underwent non-contrast chest CT between 1 January 2005-31 December 2008. CT images were reviewed for left and right ventricular fat. Electronic records identified clinical variables. Kaplan-Meier and Cox proportional hazard analyses assessed the association between myocardial fat and all-cause mortality. The net reclassification improvement assessed the utility of adding myocardial fat to traditional risk prediction models. RESULTS: Mortality was 40.1% for the no MI and 71.7% for the MI groups (median follow-up, 6.8 years; mean age, 73.7 ± 10.6 years). In the no MI group, 25.7% had LV and 49.9% RV fat. In the MI group, 32.8% had LV and 42.3% RV fat. LV and RV fat was highly associated (OR 5.3, p < 0.001). Ventricular fat was not associated with cardiovascular risk factors. Myocardial fat was associated with a reduction in the adjusted hazard of death for both the no MI (25%, p = 0.04) and the MI group (31%, p = 0.018). Myocardial fat resulted in the correct reclassification of 22% for the no MI group versus the Charlson score or calcium score (p = 0.004) and 47% for the MI group versus the Charlson score (p = 0.0006). CONCLUSIONS: Patients with myocardial fat have better survival, regardless of MI status, suggesting that myocardial fat is a beneficial biomarker and may improve risk stratification. KEY POINTS: • Myocardial fat is commonly found on chest CT, yet is poorly understood • Myocardial fat is associated with better survival in patients with and without prior MI and is not associated with traditional cardiovascular risk factors • This finding may provide clinically meaningful prognostic value in the risk stratification of patients.

Can Discrepancies Between Coronary Computed Tomography Angiography and Cardiac Catheterization in High-Risk Patients be Overcome With Consensus Reading?

OBJECTIVE: To assess the incidence and cause of discrepancies between coronary computed tomography angiography (CTA) and catheterization in a high-risk, diverse, predominantly overweight inner-city population. METHODS: Ninety-two patients who underwent coronary CTA and catheterization on March 2007 to December 2012 were retrospectively identified. Clinical coronary CTA interpretation and reinterpretation by a review panel was compared with catheterization results. RESULTS: Severe stenosis was present on catheterization in 65% (60/92). Clinical coronary CTA was concordant with catheterization for severe stenosis in 78% (72/92), whereas panel interpretation was concordant in 77% (70/91). Sensitivity and specificity of clinical and panel coronary CTA interpretations were 92% (55/60) and 53% (17/32) versus 82% (48/59) and 68% (22/32), respectively. CONCLUSIONS: Both coronary CTA interpretations were concordant with catheterization for severe stenosis in three quarters of patients. However, the diagnostic profile of the 2 interpretations differed, with higher sensitivity for the clinical report. This supports the clinical practice, which favored overestimation of difficult to quantify stenoses.

Prospective study of a non-restrictive decision rule for acute aortic syndrome.

OBJECTIVES: To determine the impact of a non-restrictive clinical decision rule on CT utilization for Emergency Department patients suspected of having an acute aortic syndrome (AAS). METHODS: We prospectively assessed the performance of a previously described, collaboratively designed, non-restrictive clinical decision rule for AAS. Emergency Department patients with suspected AAS were stratified into low and high-risk groups based on decision rule results, from July 2013-August 2014. Patients with acute trauma, prior AAS or aortic surgery were excluded. CT dose reduction protocols were concurrently implemented as a quality improvement measure. Bivariate analysis was performed to compare the prospective cohort with the historical derivation cohort for CT utilization rates, results of CT, AAS incidence and radiation exposure. The performance of the clinical decision rule was evaluated. RESULTS: Compared with the historic cohort, the study cohort demonstrated a lower CT utilization rate [0.344% (427/124,093) versus 0.477% (1465/306,961), (p<0.001)], a trend toward higher CT diagnostic yield [4.4% (19/427) versus 2.7% (40/1465), (p=0.08)]. AAS incidence was similar [0.015% (19/124,093) versus 0.013% (40/306,961), (p=0.57)]. The mean effective radiation dose was markedly lower [12±5.5mSv versus 43±20mSv, (p<0.0001)]. The clinical decision rule correctly stratified only 56% (10/18) of patients with AAS as high-risk. CONCLUSIONS: A non-restrictive, collaboratively designed, clinical decision rule for Emergency Department patients with suspected AAS performed poorly in risk-stratifying patients for AAS. However, its implementation was associated with a significant and safe decrease in CT utilization.

Coronary Computed Tomography Angiography Versus Radionuclide Myocardial Perfusion Imaging in Patients With Chest Pain Admitted to Telemetry: A Randomized Trial.

BACKGROUND: The role of coronary computed tomography angiography (CCTA) in the management of symptomatic patients suspected of having coronary artery disease is expanding. However, prospective intermediate-term outcomes are lacking. OBJECTIVE: To compare CCTA with conventional noninvasive testing. DESIGN: Randomized, controlled comparative effectiveness trial. (ClinicalTrials.gov: NCT00705458). SETTING: Telemetry-monitored wards of an inner-city medical center. PATIENTS: 400 patients with acute chest pain (mean age, 57 years); 63% women; 54% Hispanic and 37% African-American; and low socioeconomic status. INTERVENTION: CCTA or radionuclide stress myocardial perfusion imaging (MPI). MEASUREMENTS: The primary outcome was cardiac catheterization not leading to revascularization within 1 year. Secondary outcomes included length of stay, resource utilization, and patient experience. Safety outcomes included death, major cardiovascular events, and radiation exposure. RESULTS: Thirty (15%) patients who had CCTA and 32 (16%) who had MPI underwent cardiac catheterization within 1 year. Fifteen (7.5%) and 20 (10%) of these patients, respectively, did not undergo revascularization (difference, -2.5 percentage points [95% CI, -8.6 to 3.5 percentage points]; hazard ratio, 0.77 [CI, 0.40 to 1.49]; P = 0.44). Median length of stay was 28.9 hours for the CCTA group and 30.4 hours for the MPI group (P = 0.057). Median follow-up was 40.4 months. For the CCTA and MPI groups, the incidence of death (0.5% versus 3%; P = 0.12), nonfatal cardiovascular events (4.5% versus 4.5%), rehospitalization (43% versus 49%), emergency department visit (63% versus 58%), and outpatient cardiology visit (23% versus 21%) did not differ. Long-term, all-cause radiation exposure was lower for the CCTA group (24 versus 29 mSv; P < 0.001). More patients in the CCTA group graded their experience favorably (P = 0.001) and would undergo the examination again (P = 0.003). LIMITATION: This was a single-site study, and the primary outcome depended on clinical management decisions. CONCLUSION: The CCTA and MPI groups did not significantly differ in outcomes or resource utilization over 40 months. Compared with MPI, CCTA was associated with less radiation exposure and with a more positive patient experience. PRIMARY FUNDING SOURCE: American Heart Association.

Can non-contrast-enhanced CT (NECT) triage patients suspected of having non-traumatic acute aortic syndromes (AAS)?

This work was conducted to determine whether non-contrast-enhanced CT (NECT) of patients with suspected acute aortic syndrome (AAS) can identify patients with a very low likelihood of a positive diagnosis. In the derivation phase, patients who received both NECT and contrast-enhanced CT angiography (CTA) for suspected AAS were identified. Two readers blinded to CTA results analyzed NECTs from AAS positive and negative cases, recording maximal aortic diameters and qualitative findings of aortic disease. Logistic regression analysis was performed to identify independent positive predictors for AAS; those predictors were then used to create a decision rule. For the validation phase, NECTs from patients evaluated for AAS at a second institution were reviewed by two independent readers who recorded the presence of decision rule predictors while blinded to CTA results. In the derivation phase, 34 CTA positive and 83 CTA negative cases were reviewed. Measurements of aortic diameter alone achieved mean sensitivity and specificity of 82 % and of 83 %, respectively. Logistic regression identified aortic diameter, displaced calcifications, high attenuation aortic wall and abnormal aortic contour as independent predictors of AAS. The decision rule incorporating these findings achieved higher mean sensitivity (93 %), negative predictive value (96 %), and moderate reader agreement (kappa = 0.59). For the validation phase, application of the decision rule to 35 AAS positive and 45 AAS negative cases at the second institution yielded sensitivity of 100 % and specificity of 74 % for both readers. NECT can identify patients with a very low likelihood of AAS and potentially mitigate the urgency of performing CTA.

Evaluation of the cardiac chambers on axial CT: comparison with echocardiography.

OBJECTIVE: To evaluate qualitative and simple quantitative measures of all 4 cardiac chamber sizes on computed tomography (CT) in comparison with transthoracic echocardiography (TTE). METHODS: We retrospectively identified 104 adults with electrocardiographically gated cardiac CT and TTE within 3 months. Axial early diastolic (75% R-R) CT images were reviewed for qualitative chamber enlargement, and each chamber was measured linearly. Transthoracic echocardiography was reviewed for linear, area, and volume measurements. Interrater agreement was calculated using Cohen κ and Pearson correlation. RESULTS: There were significant correlations between linear left atrium and left ventricle sizes by CT and TTE (r = 0.686 and r = 0.709, respectively). Correlations for right atrium and right ventricle measurements were lower (r = 0.447 and r = 0.492, respectively). Agreement between CT and TTE for qualitative chamber enlargement was poor (highest κ = 0.35). Computed tomography sensitivity was ≤ 62% for enlargement of all chambers. CONCLUSIONS: Linear CT measurements of left-sided chamber sizes correlate well with TTE. Right heart measurements and qualitative assessments agreed poorly with TTE.

Rationale and design of a randomized trial comparing initial stress echocardiography versus coronary CT angiography in low-to-intermediate risk emergency department patients with chest pain.

BACKGROUND: Comparative effectiveness research (CER) has become a major focus of cardiovascular disease investigation to optimize diagnosis and treatment paradigms and decrease healthcare expenditures. Acute chest pain is a highly prevalent reason for evaluation in the Emergency Department (ED) that results in hospital admission for many patients and excess expense. Improvement in noninvasive diagnostic algorithms can potentially reduce unnecessary admissions. OBJECTIVE: To compare the performance of treadmill stress echocardiography (SE) and coronary computed tomography angiography (CTA) in ED chest pain patients with low-to-intermediate risk of significant coronary artery disease. DESIGN: This is a single-center, randomized controlled trial (RCT) comparing SE and CTA head-to-head as the initial noninvasive imaging modality. The primary outcome measured is the incidence of hospitalization. The study is powered to detect a reduction in admissions from 28% to 15% with a sample size of 400. Secondary outcomes include length of stay in the ED/hospital and estimated cost of care. Safety outcomes include subsequent visits to the ED and hospitalizations, as well as major adverse cardiovascular events at 30 days and 1 year. Patients who do not meet study criteria or do not consent for randomization are offered entry into an observational registry. CONCLUSIONS: This RCT will add to our understanding of the roles of different imaging modalities in triaging patients with suspected angina. It will increase the CER evidence base comparing SE and CTA and provide insight into potential benefits and limitations of appropriate use of treadmill SE in the ED.

Association of cardiometabolic and vascular atherosclerosis phenotypes on non-contrast chest CT with incident heart failure in patients with severe hypercholesterolemia.

BACKGROUND: Coronary artery calcium (CAC), thoracic aorta calcification (TAC), non-alcoholic fatty liver disease (NAFLD), and epicardial adipose tissue (EAT) are associated with atherosclerotic cardiovascular disease (ASCVD) and heart failure (HF). OBJECTIVES: We aimed to determine whether these cardiometabolic and atherosclerotic risk factors identified by non-contrast chest computed tomography (CT) are associated with HF hospitalizations in patients with LDL-C≥ 190 mg/dL. METHODS: We conducted a retrospective cohort analysis of patients with LDL-C ≥190 mg/dL, aged ≥40 years without established ASCVD or HF, who had a non-contrast chest CT within 3 years of LDL-C measurement. Ordinal CAC, ordinal TAC, EAT, and NAFLD were measured. Kaplan-Meier curves and multivariable Cox regression models were built to ascertain the association with HF hospitalization. RESULTS: We included 762 patients with median age 60 (53-68) years, 68% (n=520) female, and median LDL-C level of 203 (194-216) mg/dL. Patients were followed for 4.7 (interquartile range 2.75-6.16) years, and 107 (14%) had a HF hospitalization. Overall, 355 (47%) patients had CAC=0, 210 (28%) had TAC=0, 116 (15%) had NAFLD, and median EAT was 79 mL (49-114). Moderate-Severe CAC (log-rank p<0.001) and TAC (log-rank p=0.006) groups were associated with increased HF hospitalizations. This association persisted when considering myocardial infarction (MI) as a competing risk. NAFLD and EAT volume were not associated with HF. CONCLUSIONS: In patients without established ASCVD and LDL-C≥190 mg/dL, CAC was independently associated with increased HF hospitalizations while TAC, NAFLD, and EAT were not.

Resting cardiac 64-MDCT does not reliably detect myocardial ischemia identified by radionuclide imaging.

OBJECTIVE: CT myocardial perfusion imaging is an emerging diagnostic modality that is under intensive study but not yet widely used in clinical practice. The purpose of this study is to evaluate the performance of resting 64-MDCT in revealing ischemia identified on radionuclide myocardial perfusion imaging (MPI). MATERIALS AND METHODS: We retrospectively identified 35 patients (20 women and 15 men; mean age, 52 years) with myocardial ischemia found on MPI who underwent retrospectively gated CT within 90 days of MPI. Myocardial perfusion on CT was evaluated using both a visual (n = 35) and an automated (n = 34) method. For the visual method, myocardial segments were evaluated qualitatively in systole and diastole. For the automated method, subendocardial perfusion of the standard 17 American Heart Association segments was measured using a commercially available tool in both systole and diastole. Differences between systolic and diastolic perfusion were computed. RESULTS: Five hundred eighty myocardial segments were evaluated, 152 of which were ischemic on MPI. Visual analysis had a sensitivity of 16% (24/152), specificity of 92% (393/428), positive predictive value of 40% (24/60), and negative predictive value of 75% (392/520) in systole, and a sensitivity of 18% (27/152), specificity of 89% (382/428), positive predictive value of 37% (27/73), and negative predictive value of 75% (382/507) in diastole, as compared with MPI. There was no significant difference in subendocardial perfusion between ischemic and nonischemic segments by the automated method. There was no significant difference in CT perfusion between patients with and without obstructive coronary artery disease on CT angiography using the visual or automated methods. CONCLUSION: Resting 64-MDCT is unsuitable for clinical use in revealing ischemia seen on MPI.

Acute aortic syndromes: a second look at dual-phase CT.

OBJECTIVE: The purpose of this article is to assess the diagnostic performance of the unenhanced and contrast-enhanced phases separately in patients imaged with CT for suspected acute aortic syndromes. MATERIALS AND METHODS: All adults (n = 2868) presenting to our emergency department from January 1, 2006, through August 1, 2010, who underwent unenhanced and contrast-enhanced CT of the chest and abdomen for suspected acute aortic syndrome were retrospectively identified. Forty-five patients with acute aortic syndrome and 45 healthy control subjects comprised the study population (55 women; mean age, 61 ± 16 years). Unenhanced followed by contrast-enhanced CT angiography (CTA) images were reviewed. Contrast-enhanced CTA examinations of case patients and control subjects with isolated intramural hematoma were reviewed. Radiation exposure was estimated by CT dose-length product. RESULTS: Forty-five patients had one or more CT findings of acute aortic syndrome: aortic dissection (n = 32), intramural hematoma (n = 27), aortic rupture (n = 10), impending rupture (n = 4), and penetrating atherosclerotic ulcer (n = 2). Unenhanced CT was 89% (40/45) sensitive and 100% (45/45) specific for acute aortic syndrome. Unenhanced CT was 94% (17/18) and 71% (10/14) sensitive for type A and type B dissection, respectively (p = 0.142). Contrast-enhanced CTA was 100% (8/8) sensitive for isolated intramural hematoma. Mean radiation effective dose was 43 ± 20 mSv. CONCLUSION: Unenhanced CT performed well in detection of acute aortic syndrome treated surgically, although its performance does not support its use in place of contrast-enhanced CTA. Unenhanced CT may be a reasonable first examination for rapid triage when IV contrast is contraindicated. Contrast-enhanced CTA was highly sensitive for intramural hematoma, suggesting that unenhanced imaging may not always be needed. Acute aortic syndrome imaging protocols should be optimized to reduce radiation dose.

Preliminary development of a clinical decision rule for acute aortic syndromes.

OBJECTIVE: Patients with suspected acute aortic syndromes (AAS) often undergo computed tomography (CT) with negative results. We sought clinical and diagnostic criteria to identify low-risk patients, an initial step in developing a clinical decision rule. METHODS: We retrospectively identified all adults presenting to our emergency department (ED) from January 1, 2006, to August 1, 2010, who underwent CT angiography for suspected AAS without prior trauma or AAS. A total of 1465 patients met inclusion criteria; a retrospective case-controlled review (ratio 1:4) was conducted. Cases were diagnosed with aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, or ruptured aneurysm. RESULTS: Of the patients who underwent CT, 2.7% (40/1465) had an AAS; 2 additional cases were diagnosed after admission (ED miss rate, 5% [2/42]). Patients with AAS were significantly older than controls (66 vs 59 years; P = .008). Risk factors included abnormal chest radiograph (sensitivity, 79% [26/33]; specificity, 82% [113/137]) and acute chest pain (sensitivity, 83% [29/35]; specificity, 71% [111/157]). None of the 19 patients with resolved pain upon ED presentation had AAS. These data support a 2-step rule: first screen for ongoing pain; if present, screen for acute chest pain or an abnormal chest radiograph. This approach achieves a 54% (84/155) reduction in CT usage with a sensitivity for AAS of 96% (95% confidence interval, 89%-100%), negative predictive value of 99.8% (99.4%-100%), and a false-negative rate of 1.7% (1/84). CONCLUSIONS: Our results demonstrate a need to safely identify patients at low risk for AAS who can forgo CT. We developed a preliminary 2-step clinical decision rule, which requires validation.

Coronary Calcium Predicts All-Cause Mortality in Suspected Acute Aortic Syndrome.

Purpose: To determine long-term clinical outcomes in patients with suspected acute aortic syndrome (AAS) and evaluate the prognostic value of coronary calcium burden as assessed with CT aortography in this symptomatic population. Materials and Methods: A retrospective cohort of all patients who underwent emergency CT aortography from January 2007 through January 2012 for suspected AAS was assembled. A medical record survey tool was used to evaluate subsequent clinical events over 10 years of follow-up. Events included death, aortic dissection, myocardial infarction, cerebrovascular accident, and pulmonary embolism. Coronary calcium scores were computed from original images using a validated simple 12-point ordinal method and categorized into none, low (1-3), moderate (4-6), or high (7-12) groupings. Survival analysis with Kaplan-Meier curves and Cox proportional hazard modeling was performed. Results: The study cohort comprised 1658 patients (mean age, 60 years ± 16 [SD]; 944 women), with 595 (35.9%) developing a clinical event over a median follow-up of 6.9 years. Patients with high coronary calcium demonstrated the highest mortality rate (adjusted hazard ratio = 2.36; 95% CI: 1.65, 3.37). Patients with low coronary calcium demonstrated lower mortality, but rates were still almost twice as high compared with patients with no detectable calcium (adjusted hazard ratio = 1.89; 95% CI: 1.41, 2.53). Coronary calcium was a strong predictor of major adverse cardiovascular events (P < .001), which persisted after adjustment for common significant comorbidities. Conclusion: Patients with suspected AAS had a high rate of subsequent clinical events, including death. CT aortography-based coronary calcium scores strongly and independently predicted all-cause mortality.Keywords: Acute Aortic Syndrome, Coronary Artery Calcium, CT Aortography, Major Adverse Cardiovascular Events, Mortality Supplemental material is available for this article. © RSNA, 2023See also commentary by Weir-McCall and Shambrook in this issue.