Existing Nongated CT Coronary Calcium Predicts Operative Risk in Patients Undergoing Noncardiac Surgeries (ENCORES).

BACKGROUND: Preoperative cardiovascular risk stratification before noncardiac surgery is a common clinical challenge. Coronary artery calcium scores from ECG-gated chest computed tomography (CT) imaging are associated with perioperative events. At the time of preoperative evaluation, many patients will not have had ECG-gated CT imaging, but will have had nongated chest CT studies performed for a variety of noncardiac indications. We evaluated relationships between coronary calcium severity estimated from previous nongated chest CT imaging and perioperative major clinical events (MCE) after noncardiac surgery. METHODS: We retrospectively identified consecutive adults age ≥45 years who underwent in-hospital, major noncardiac surgery from 2016 to 2020 at a large academic health system composed of 4 acute care centers. All patients had nongated (contrast or noncontrast) chest CT imaging performed within 1 year before surgery. Coronary calcium in each vessel was retrospectively graded from absent to severe using a 0 to 3 scale (absent, mild, moderate, severe) by physicians blinded to clinical data. The estimated coronary calcium burden (ECCB) was computed as the sum of scores for each coronary artery (0 to 9 scale). A Revised Cardiac Risk Index was calculated for each patient. Perioperative MCE was defined as all-cause death or myocardial infarction within 30 days of surgery. RESULTS: A total of 2554 patients (median age, 68 years; 49.7% women; median Revised Cardiac Risk Index, 1) were included. The median time interval from nongated chest CT imaging to noncardiac surgery was 15 days (interquartile range, 3-106 days). The median ECCB was 1 (interquartile range, 0-3). Perioperative MCE occurred in 136 (5.2%) patients. Higher ECCB values were associated with stepwise increases in perioperative MCE (0: 2.9%, 1-2: 3.7%, 3-5: 8.0%; 6-9: 12.6%, P<0.001). Addition of ECCB to a model with the Revised Cardiac Risk Index improved the C-statistic for MCE (from 0.675 to 0.712, P=0.018), with a net reclassification improvement of 0.428 (95% CI, 0.254-0.601, P<0.0001). An ECCB ≥3 was associated with 2-fold higher adjusted odds of MCE versus an ECCB <3 (adjusted odds ratio, 2.11 [95% CI, 1.42-3.12]). CONCLUSIONS: Prevalence and severity of coronary calcium obtained from existing nongated chest CT imaging improve preoperative clinical risk stratification before noncardiac surgery.

Pitfalls and Pearls of Imaging Non-traumatic Thoracic Aortic Disease.

Imaging of the thoracic aorta is a common request in both the acute and outpatient settings, playing a crucial role in diagnosis and treatment planning of aortic disease. The findings of aortic pathology may be obvious or occult on imaging. Recognizing subtle changes is essential and may lead to early detection and prevention of serious morbidity and mortality. Knowledge of the anatomy and understanding the pathophysiology of aortic disease, as well as selecting the appropriate imaging modality and protocol will enable prompt diagnosis and early intervention of aortic pathology. Currently, computed tomography angiography and magnetic resonance angiography of the aorta are the most commonly used imaging modalities to evaluate the aorta. This review focuses on a spectrum of aortic pathology manifestations on computed tomography and magnetic resonance, including atherosclerosis and acute aortic syndromes, highlighting diagnostic challenges and approaches to aid in image interpretation.

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.

Meeting ACR Dose Guidelines for CT Lung Cancer Screening in an Overweight and Obese Population.

RATIONALE AND OBJECTIVES: Lung cancer screening adoption coincides with a growing obesity epidemic. Maintaining high-quality imaging at low radiation dose is challenging in obesity. We investigate the feasibility of meeting American College of Radiology (ACR) dose guidelines for lung cancer screening in a predominantly overweight and obese population. MATERIALS AND METHODS: Radiation dose (Volumetric CT dose index [CTDIvol], dose-length product), and body mass index (BMI) were collected for baseline screening CTs December, 2012-December, 2017. Dose metrics were analyzed according to BMI classification (normal <25, overweight 25-29, obese ≥30 kg/m2), using k = 0.014 mSv/mGy*cm. Results were compared to ACR dose guidelines and mean national 2017 Lung Cancer Screening Registry dose metrics. Analysis used Kruskal-Wallis (SPSS, version 24.0.0, IBM corp, Armonk, NY). RESULTS: Study population comprised 1478 patients (49.2% [727] women: mean BMI 28.1 ± 6.5 kg/m2, 26.9% [397] normal weight, 35.9% [530] overweight, 37.2% [551] obese). ACR dose requirements were met for both genders in all BMI classifications. Dose metrics were higher in men than in women; median effective dose and CTDIvol were 1.39 (0.8-1.58) mSv and 2.78 (1.41-2.80) mGy in men versus 1.16 (0.71-1.43) mSv and 2.70 (1.4-2.78) mGy in women. There were significant differences in dose metrics between men and women in the same BMI classification and between BMI classifications (p < 0.001). Mean dose metrics in our program were considerably lower than 2017 national average- mean CTDIvol and effective dose 2.45 ± 1.14 mGy and 1.26 ± 0.59 mSv versus 3.24 mGy and 1.35 mSv, respectively for our program and nationally. Mean dose metrics were also lower in our obese patients versus obese patients nationally. CONCLUSION: ACR dose metrics for lung cancer screening were met and can be appropriately tailored in a predominantly overweight and obese population clinical program.

Cracking the Opium Den: Cardiothoracic Manifestations of Drug Abuse.

Recreational drug use is increasing worldwide, with emergency room visits and total deaths from drug overdose rising in recent years. Complications from prescription and recreational drug use may result from the biochemical effects of the drugs themselves, impurities mixed with substances, or from causes related to the method of drug administration. The presentation of drug overdose may be complex due to multisubstance abuse, including cigarette smoking and alcoholism, and can impact any organ system. Patients may present without history, and radiologists may be the first clinicians to suggest the diagnosis. We aim to explore the cardiothoracic manifestations of drug abuse and their multimodality imaging manifestations.

Utility of Apical Lung Assessment on Computed Tomography Angiography as a COVID-19 Screen in Acute Stroke.

BACKGROUND AND PURPOSE: Evaluation of the lung apices using computed tomography angiography of the head and neck during acute ischemic stroke (AIS) can provide the first objective opportunity to screen for coronavirus disease 2019 (COVID-19). METHODS: We performed an analysis assessing the utility of apical lung exam on computed tomography angiography for COVID-19-specific lung findings in 57 patients presenting with AIS. We measured the diagnostic accuracy of apical lung assessment alone and in combination with patient-reported symptoms and incorporate both to propose a COVID-19 era AIS algorithm. RESULTS: Apical lung assessment when used in isolation, yielded a sensitivity of 0.67, specificity of 0.93, positive predictive value of 0.19, negative predictive value of 0.99, and accuracy of 0.92 for the diagnosis of COVID-19, in patients presenting to the hospital for AIS. When combined with self-reported clinical symptoms of cough or shortness of breath, sensitivity of apical lung assessment improved to 0.83. CONCLUSIONS: Apical lung assessment on computed tomography angiography is an accurate screening tool for COVID-19 and can serve as part of a combined screening approach in AIS.

Effectiveness of Lung-RADS in Reducing False-Positive Results in a Diverse, Underserved, Urban Lung Cancer Screening Cohort.

PURPOSE: The Lung CT Screening Reporting and Data SystemTM (Lung-RADSTM) was created to standardize lung cancer screening CT reporting and recommendations but has not been well validated prospectively in clinical practice. The aim of this study was to determine the effectiveness of lung cancer screening using Lung-RADS in a diverse, underserved, academic clinical screening program, focusing on whether Lung-RADS would successfully reduce the 23.3% false-positive rate found in the National Lung Screening Trial. METHODS: Institutional review board approval was obtained to study the clinical lung cancer screening cohort. Low-dose CT results were prospectively assigned a Lung-RADS or equivalent score. The proportion of examinations in each Lung-RADS category and the corresponding lung cancer rate, subsequent imaging, interventions, mortality, and compliance were tracked. The National Death Index was queried for follow-up losses. RESULTS: The cohort comprised 1,181 patients with 2,270 person-years of follow-up from December 2012 to December 2016. The mean age was 64 ± 16.2 years, with 51% women, 63% nonwhite, 71% current smokers, 69% overweight and obese, and multiple comorbidities. The Lung-RADS false-positive rate was 10.4% (95% confidence interval, 8.8%-12.3%). Baseline CT results were negative in 87% (n = 1,031): for Lung-RADS 1, the lung cancer rate was 0.2%, and for Lung-RADS 2, the cancer rate was 0.5%. Positive baseline examinations were Lung-RADS 3 in 10% (n = 119), 4a in 1.2% (n = 14), and 4b in 1.5% (n = 18). Corresponding cancer rates were 3.4%, 43%, and 83%, respectively. Lung cancer prevalence was 2.1%. Mortality was 40% in patients with lung cancer versus 2.5% in the remaining cohort (P < .001). Fifty-four percent of patients were overdue for first annual examinations. Eighty-four percent of patients (n = 989) had follow-up verified via electronic records or personal contact, and the remainder had vital status ascertained via the National Death Index. CONCLUSIONS: Lung cancer screening using Lung-RADS was effective in reducing the false-positive rate compared with the National Lung Screening Trial in a diverse and underserved urban population.

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.

Navigating the Pulmonary Perfusion Map: Dual-Energy Computed Tomography in Acute Pulmonary Embolism.

Pulmonary embolism is the third most common acute cardiovascular disease. Dual-energy computed tomography perfusion imaging is a promising adjunct in the detection of acute PE providing simultaneous functional assessment of pulmonary perfusion alongside the high-resolution morphological information from computed tomography pulmonary angiography. We review the evidence to date and common causes of perfusion defects including artifacts, parenchymal, and vascular causes, and discuss its potential in furthering our understanding of physiology and pathophysiology in acute pulmonary embolism.

Patent foramen ovale in patients with pulmonary embolism: A prognostic factor on CT pulmonary angiography?

BACKGROUND: Patent foramen ovale (PFO) in patients with acute pulmonary embolism (PE) represents a risk factor for mortality, but this has not been evaluated for CT pulmonary angiography (CTPA). The purpose of the present study was to assess the relationship between PFO and mortality in patients with acute PE diagnosed on CTPA. MATERIALS AND METHODS: This retrospective study included 268 adults [173 women, mean age 61 (range 22-98) years] diagnosed with acute PE on non-ECG-gated 64-slice CTPA in 2012 at our medical center. The images were reviewed for PFO by a panel of cardiothoracic radiologists with an average of 11 years of experience (range 1-25 years). CT signs of right heart strain and PE level were noted. Transthoracic echocardiograms (TTE), when available (n = 207), were reviewed for PFO by a cardiologist with subspecialty training in advanced imaging and with 3 years of experience. The main outcome was 30-day mortality. Fischer's exact test was utilized to compare mortality. RESULTS: PFO prevalence on CTPA was 22% (58/268) and 4% (9/207) on TTE. Overall 30-day mortality was 6% (16/268), 9% (5/58) for patients with PFO and 5% (11/210) for those without (p = 0.35). CT signs of right heart strain trended with higher mortality, but statistically significant only for hepatic vein contrast reflux [14% (6/44) vs 4% (10/224), p = 0.03]; right ventricular (RV) to left ventricular (LV) diameter ratio >1 [8% (13/156) vs RV:LV ≤ 1 3% (3/112), p = 0.07], septal bowing [10% (4/42) vs without 5% (12/226), p = 0.30]. CONCLUSION: PFO was demonstrated on CTPA in a proportion similar to the known population prevalence, while routine TTE was less sensitive. Mortality was non-significantly higher in patients with acute PE and PFO in this moderate-sized study. A larger study to answer this clinically important question is worthwhile.

False-Positive Ventilation-Perfusion Studies Due to Nonembolic Pulmonary Artery Compromise.

Ventilation/perfusion (V/Q) scans are highly sensitive in detecting clinically significant pulmonary embolisms; however, V/Q mismatches are not specific to pulmonary embolism alone, and other etiologies can cause false-positive results. We present 3 cases where the pulmonary vasculature was compromised, from either intraluminal narrowing or external compression, with resultant mismatches. This raises the importance of interpreting V/Q scan results in conjunction with a thorough medical/surgical history and careful analysis of the chest radiograph.

Viruses, Immunity and Unusual Lymphoproliferative Disorders of the Chest: Integrating Imaging With Pathogenesis and Clinical Presentations.

Unusual lymphoproliferative diseases result from the stimulation of intrathoracic lymphoid tissue by viruses and immune dysfunction, ranging from benign hyperplasia to malignant transformation. We review the clinical, radiological, and histopathological findings of unusual lymphoproliferative disorders, which have been linked to viruses or immune dysfunction, focusing on thoracic manifestations. Understanding these advances in science enhances the radiologist's skills in integrating the imaging findings to the clinical scenario to suggest the correct diagnosis.

Computed tomography screening for lung cancer: preliminary results in a diverse urban population.

PURPOSE: The purpose of this study was to describe the baseline characteristics and results of the initial 18 months of our clinical computed tomography (CT) lung cancer screening program in an ethnically diverse, poor, predominantly overweight, and obese population, which differs dramatically from the National Lung Screening Trial population. MATERIALS AND METHODS: All patients had a physician referral for CT lung cancer screening and met National Lung Screening Trial eligibility criteria. Infrastructure developed for the program included a standardized results report [Bronx score of 1 to 5 (modeled on BI-RADS)] for the electronic medical record and a dedicated bilingual screening coordinator. If the patient's insurance did not cover CT screening, a fee of $75 was charged. RESULTS: A total of 320 patients [54% (174) men, mean age 64 y] underwent initial CT lung cancer screening from December 18, 2012 to July 3, 2014. The median pack-years was 47, and 68% (218) were current smokers. Twenty-six percent (84) were white, and 70% (223) were overweight (101) or obese (122). The lung cancer prevalence was 2.2% (7/320). Seventy-eight percent (7/9) of patients with CT findings positive for lung cancer (score 5a, 5b) had proven lung cancer; 1 had stage 1 (1B) disease, and 6 had stage IIA or higher disease. The false-positive rate for a Bronx score ≥3 was 19% (60). Medicare and Medicaid insure 80% of the institution's overall population but only 38% (121) of the CT screening patients. CONCLUSIONS: CT screening is feasible in a diverse inner-city population with the support of a robust infrastructure. Further study is needed to determine whether CT screening will confer a mortality benefit in this population.