Imaging Utilization and Cost of Substance Use in an Urban Academic Medical Center During the Contemporary Opioid Epidemic

RATIONALE AND OBJECTIVES

To determine the recent impact of illicit substance use on imaging utilization and associated costs.

METHODS

Retrospective study from an inner city urban multi-site academic medical center. Institutional Review Board (IRB) approval was obtained with a waiver of informed consent. A substance use cohort comprised patients 12 years old presenting to the Emergency Department (ED) January 2017 to June 2019 with a positive urine toxicology and an ICD code associated with substance use. The comparison cohort was randomly selected from a group of ED patients who presented with no or negative urine toxicology and no documented substance use ICD code. Data extracted from the EMR included demographics, number and type of imaging studies, Charlson comorbidity index, and in-hospital mortality during the study period.

RESULTS

The substance use and comparison cohorts comprised 3191 and 3200 patients, respectively. The substance use cohort was older on average (mean age 45.67 ± 14.88 vs 43.91 ± 20.57 years), more often male (63% [2026/3191] vs. 39% [1255/3200]) and had a mean Charlson score 88% higher than the comparison cohort (3.33 vs 1.78). The majority of both cohorts were ethnic minorities (<10% white). The substance use cohort had significantly more imaging vs the comparison cohort, total 36,413 (mean 11.41 exams/patient) vs total 12,399 (mean 3.87 exams/patient), p < 0.0001, and was higher for all modalities except mammography. Average imaging costs per patient were nearly 300% higher for the substance use vs comparison cohort, ($1287.18 vs. $434.70).

CONCLUSION

Imaging utilization and associated costs were substantially higher for patients with a positive urine toxicology and substance use related ICD codes compared to the broader ED population in an underserved urban population.

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.

Predictive Value of CT Biomarkers in Lung Transplantation Survival: Preliminary Investigation in a Diverse, Underserved, Urban Population

INTRODUCTION

Survival following lung transplant is low. With limited donor lung availability, predicting post-transplant survival is key. We investigated the predictive value of pre-transplant CT biomarkers on survival.

METHODS

In this single-center retrospective cohort study of adults in a diverse, underserved, urban lung transplant program (11/8/2017-5/20/2022), chest CTs were analyzed using TeraRecon to assess musculature, fat, and bone. Erector spinae and pectoralis muscle area and attenuation were analyzed. Sarcopenia thresholds were 34.3 (women) and 38.5 (men) Hounsfield Units (HU). Visceral and subcutaneous fat area and HU, and vertebral body HU were measured. Demographics and pre-transplant metrics were recorded. Survival analyses included Kaplan-Meier and Cox proportional hazard.

RESULTS

The study cohort comprised 131 patients, 50 women, mean age 60.82 (SD 10.15) years, and mean follow-up 1.78 (SD 1.23) years. Twenty-nine percent were White. Mortality was 32.1%. Kaplan-Meier curves did not follow the proportional hazard assumption for sex, so analysis was stratified. Pre-transplant EMR metrics did not predict survival. Women without sarcopenia at erector spinae or pectoralis had 100% survival (p = 0.007). Sarcopenia did not predict survival in men and muscle area did not predict survival in either sex. Men with higher visceral fat area and HU had decreased survival (p = 0.02). Higher vertebral body density predicted improved survival in men (p = 0.026) and women (p = 0.045).

CONCLUSION

Pre-transplantation CT biomarkers had predictive value in lung transplant survival and varied by sex. The absence of sarcopenia in women, lower visceral fat attenuation and area in men, and higher vertebral body density in both sexes predicted survival in our diverse, urban population.

Lung Cancer Screening Among Mammography Patients: Knowledge, Eligibility, Participation, and Interest

OBJECTIVE

To determine lung cancer screening eligibility, knowledge, and interest and to quantify the effect of the expanded 2021 lung cancer screening eligibility criteria among women presenting for screening mammography, a group with demonstrable interest in cancer screening.

METHODS

A single-page survey was distributed to patients presenting for screening mammography, from January-March 2020 and June 2020-January 2021, at 2 academic medical centers on the East and West Coasts. The population served by the East Coast institution has greater poverty, greater ethnic/racial diversity, and lower education levels. Survey questions included age, smoking history, lung cancer screening knowledge, participation, and interest. Lung cancer screening eligibility was determined for both 2013 and 2021 USPSTF guidelines. Descriptive statistics were calculated, and data were compared between groups using the Chi-square test, Mann-Whitney nonparametric test, and the 2-sample t test.

RESULTS

5512 surveys were completed; 33% (1824) of women reported a history of smoking-30% (1656) former smokers and 3% (156) current smokers. Among women with a smoking history, 7% (127/1824) were eligible for lung cancer screening using 2013% and 11% (207/1824) using the 2021 USPSTF criteria. Interest in lung cancer screening was high (73%; 151/207) among eligible women using 2021 USPSTF criteria, but only 42% (87/207) had heard of lung cancer screening and only 28% (57/207) had received prior LDCT screening.

CONCLUSION

Eligible screening mammography patients reported high levels of interest in lung cancer screening but low levels of knowledge and participation. Linking mammography and LDCT appointments may improve lung cancer screening participation.

Bend but don't break: Experience of a diverse New York City lung cancer screening program during the first year of the COVID-19 pandemic

RATIONALE AND OBJECTIVES

The COVID-19 pandemic led to the national shutdown and subsequent reopening of cancer screening programs. Our diverse inner-city lung cancer screening program serves patients in the Bronx NY, which was severely affected by COVID-19, with the highest mortality in New York State in the spring of 2020. Staffing redeployment, quarantine protocols, increased safety measures, and changes in follow up resulted. The purpose of this study is to analyze the effect of the pandemic on lung cancer screening volumes during the first year of the pandemic.

METHODS AND MATERIALS

Retrospective cohort comprised of all patients enrolled in our Bronx, NY lung cancer screening program from March 2019 to March 2021 who underwent LDCT or appropriate follow-up imaging. The pre-pandemic and pandemic period were defined as 3/28/2019 to 3/21/2020 and 3/22/2020 to 3/17/2021, respectively, dichotomized by the New York State lockdown.

RESULTS

1218 exams were performed in the pre-pandemic period and 857 in the pandemic period, a 29.6% decrease. The percentage of exams performed on newly enrolled patients decreased from 32.7% to 13.8% (p < 0.001). Patients in the pre-pandemic period and pandemic period respectively had the following demographic breakdown: mean age 66.9 ± 5.9 vs 66.5 ± 6.0, women 51.9% vs 51.6%, White 20.7% vs 20.3%, Hispanic/Latino 42.0% vs 36.3%. There was no significant difference in Lung-RADS scores for pre-pandemic and pandemic exams (p > 0.05). In the pandemic period, exam volume followed an inverted parabolic pattern, reflecting Covid surges for the cohort and all demographic subgroups.

CONCLUSION

The COVID-19 pandemic significantly decreased lung cancer screening volume and new enrollment in our urban inner-city program. Screening volumes demonstrated a parabolic curve reflecting pandemic surges following the initial wave, unlike other reports. The combination of the impact of COVID on our population and lack of staffing redundancy in the screening program, in the face of typical COVID isolation and quarantine absences, impeded early pandemic rebound of our lung cancer screening program. This highlights the necessity of fostering resilience by developing robust programmatic resources.

Clearing the Congestion: Chest Radiography and BNP to Rule-out Congestive Heart Failure

PURPOSE

Ruling out congestive heart failure (CHF) is clinically important in Emergency Department (ED) patients. Normal serum brain natriuretic peptide (BNP) represents an important reference standard for excluding CHF. Results of chest radiographs (CXR) are also considered and, when discordant with BNP levels, may result in a clinical dilemma. The present study was designed to elucidate factors associated with CHF on CXR in an ED cohort with normal BNP.

MATERIALS AND METHODS

All adults at our urban health system's EDs who underwent CXR within 24 hours and had a normal BNP (<300 pg/mL) within 24 hours of CXR were retrospectively identified. Of these, 0.9% (8/862) had equivocal CXRs and was excluded. Demographics, comorbidities, CXR report results for CHF, and portable technique were noted. Logistic regression was used to assess factors that are associated with the presence of CHF on CXR.

RESULTS

The study cohort comprised 854 patients (433 men, mean age 60.99±15.30) with normal BNP; 91.5% (781/854) had no CHF on CXR and 8.5% (73/854) had CHF. Patients with CHF on CXR had a higher body mass index (32.9 vs. 29.8 kg/m 2 , P =0.0205) were more likely to have a history of CHF or diabetes with complications (OR: 2.72 and 2.53, respectively), had higher serum BNP levels (median 164 vs. 98 pg/mL, P =4.91×10 -5 ), and underwent portable examination more frequently (86.3% vs. 57.5%, OR: 4.65).

CONCLUSIONS

Normal serum BNP was concordant with CXR results, adding diagnostic confidence in ruling out CHF in a large majority of ED patients. A higher body mass index, history of CHF, and diabetes with complications and portable CXR technique were associated with CHF on CXR among the minority with normal BNP.

Long-term Lung Abnormalities Associated with COVID-19 Pneumonia

In the 3rd year of the SARS-CoV-2 pandemic, much has been learned about the long-term effects of COVID-19 pneumonia on the lungs. Approximately one-third of patients with moderate-to-severe pneumonia, especially those requiring intensive care therapy or mechanical ventilation, have residual abnormalities at chest CT 1 year after presentation. Abnormalities range from parenchymal bands to bronchial dilation to frank fibrosis. Less is known about the long-term pulmonary vascular sequelae, but there appears to be a persistent, increased risk of venothromboembolic events in a small cohort of patients. Finally, the associated histologic abnormalities resulting from SARS-CoV-2 infection are similar to those seen in patients with other causes of acute lung injury.

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.

COVID-19 in Kidney Transplant Recipient and Waitlist Patients: Implications of Chest Radiographic Severity Score

PURPOSE

To evaluate the chest radiographic severity score (CXR-SS) for coronavirus disease 2019 (COVID-19) patients who are kidney transplant recipients compared with patients on the waitlist.

STUDY DESIGN AND METHODS

This retrospective cohort includes 78 kidney transplant recipients (50 men, mean age 59.9±11.9 y) and 59 kidney transplant waitlist patients (33 men, mean age 58.8±10.8 y) diagnosed with COVID-19 between March 15 and May 30, 2020 with reverse transcriptase-polymerase chain reaction. Patient chest radiographs were divided into 6 zones and examined for consolidation. Primary outcome was mortality. Secondary outcomes included hospital admission, intensive care unit (ICU) admission, and intubation. Predictors of our primary and secondary outcomes were identified by bivariate analysis and multivariate regression analysis.

RESULTS

No significant difference was found in CXR-SS between 2 groups (P=0.087). Transplant recipients had significantly higher rates of hospitalization (odds ratio, 6.8; 95% confidence interval: 1.7, 39.3; P<0.001), ICU admission (odds ratio, 6.5; 95% confidence interval [CI]: 1.8-35.9; P=0.002), intubation (odds ratio, 11; 95% CI: 2.4-96.9; P=0.001), and mortality (odds ratio, 17; 95% CI: 3.9-153.1; P<0.001). A higher CXR-SS was not predictive of mortality, intubation, or ICU admission. CXR-SS was associated with hospital admission overall (odds ratio, 1.613; 95% CI: 1.04-2.49; P=0.0314).

CONCLUSION

The CXR-SS was not predictive of mortality, ICU admission or intubation in our population. Kidney transplant patients with COVID-19 had near universal hospital admission, more than one-third mortality and about a quarter were intubated and admitted to the ICU-all significantly worse outcomes than for patients on the transplant waitlist.

Experience with a perfusion-only screening protocol for evaluation of pulmonary embolism during the COVID-19 pandemic surge

The purpose of this study was to evaluate a pulmonary embolism (PE) perfusion-only screening (POS) protocol introduced during the coronavirus disease 2019 (COVID-19) pandemic surge. Subjects without dense parenchymal lung opacities were studied; those with less than 1 segmental perfusion defect were considered to have no PE, whereas those exhibiting 1 or more defects were indeterminate, mandating additional examinations to determine the final diagnosis. Methods: We analyzed demographic information, clinical data, imaging findings, and follow-up data from the electronic records of COVID-19 patients who underwent lung scintigraphy during the 60-d study period. Results: In total, 53 studies were performed on 17 COVID-19–positive and 36 COVID-19–negative patients. The POS protocol efficiently excluded PE in 79% of cases; the remaining 21%, indeterminate for PE, were generally referred for alternative testing or were directly anticoagulated. In patients with negative POS results, there was a very low mortality before hospital discharge (1/42) and normal results on follow-up studies (6/6). Conclusion: The POS protocol, implemented during the COVID-19 surge, efficiently and safely excluded PE in 79% of patients.

COVID-19 Imaging: What We Know Now and What Remains Unknown

Infection with SARS-CoV-2 ranges from an asymptomatic condition to a severe and sometimes fatal disease, with mortality most frequently being the result of acute lung injury. The role of imaging has evolved during the pandemic, with CT initially being an alternative and possibly superior testing method compared with reverse transcriptase-polymerase chain reaction (RT-PCR) testing and evolving to having a more limited role based on specific indications. Several classification and reporting schemes were developed for chest imaging early during the pandemic for patients suspected of having COVID-19 to aid in triage when the availability of RT-PCR testing was limited and its level of performance was unclear. Interobserver agreement for categories with findings typical of COVID-19 and those suggesting an alternative diagnosis is high across multiple studies. Furthermore, some studies looking at the extent of lung involvement on chest radiographs and CT images showed correlations with critical illness and a need for mechanical ventilation. In addition to pulmonary manifestations, cardiovascular complications such as thromboembolism and myocarditis have been ascribed to COVID-19, sometimes contributing to neurologic and abdominal manifestations. Finally, artificial intelligence has shown promise for use in determining both the diagnosis and prognosis of COVID-19 pneumonia with respect to both radiography and CT.

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.

Imaging of pulmonary hypertension in adults: a position paper from the Fleischner Society

Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure greater than 20 mmHg and classified into five different groups sharing similar pathophysiologic mechanisms, haemodynamic characteristics, and therapeutic management. Radiologists play a key role in the multidisciplinary assessment and management of PH. A working group was formed from within the Fleischner Society based on expertise in the imaging and/or management of patients with PH, as well as experience with methodologies of systematic reviews. The working group identified key questions focusing on the utility of CT, MRI, and nuclear medicine in the evaluation of PH: a) Is noninvasive imaging capable of identifying PH? b) What is the role of imaging in establishing the cause of PH? c) How does imaging determine the severity and complications of PH? d) How should imaging be used to assess chronic thromboembolic PH before treatment? e) Should imaging be performed after treatment of PH? This systematic review and position paper highlights the key role of imaging in the recognition, work-up, treatment planning, and follow-up of PH.

Imaging of Pulmonary Hypertension in Adults: A Position Paper from the Fleischner Society

Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure greater than 20 mm Hg and classified into five different groups sharing similar pathophysiologic mechanisms, hemodynamic characteristics, and therapeutic management. Radiologists play a key role in the multidisciplinary assessment and management of PH. A working group was formed from within the Fleischner Society based on expertise in the imaging and/or management of patients with PH, as well as experience with methodologies of systematic reviews. The working group identified key questions focusing on the utility of CT, MRI, and nuclear medicine in the evaluation of PH: (a) Is noninvasive imaging capable of identifying PH? (b) What is the role of imaging in establishing the cause of PH? (c) How does imaging determine the severity and complications of PH? (d) How should imaging be used to assess chronic thromboembolic PH before treatment? (e) Should imaging be performed after treatment of PH? This systematic review and position paper highlights the key role of imaging in the recognition, work-up, treatment planning, and follow-up of PH. This article is a simultaneous joint publication in Radiology and European Respiratory Journal. The articles are identical except for stylistic changes in keeping with each journal's style. Either version may be used in citing this article. © 2021 RSNA and the European Respiratory Society. Online supplemental material is available for this article.

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

Supplemental Digital Content is available in the text.

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).

CT Scans Obtained for Nonpulmonary Indications: Associated Respiratory Findings of COVID-19

Background Atypical manifestations of coronavirus disease 2019 (COVID-19) are being encountered as the pandemic unfolds, leading to non-chest CT scans that may uncover unsuspected pulmonary disease. Purpose To investigate patients with primary nonrespiratory symptoms who underwent CT of the abdomen or pelvis or CT of the cervical spine or neck with unsuspected findings highly suspicious for pulmonary COVID-19. Materials and Methods This retrospective study from March 10, 2020, to April 6, 2020, involved three institutions, two in a region considered a hot spot (area of high prevalence) for COVID-19. Patients without known COVID-19 were included who presented to the emergency department (ED) with primary nonrespiratory (gastrointestinal or neurologic) symptoms, had lung parenchymal findings suspicious for COVID-19 at non-chest CT but not concurrent chest CT, and underwent COVID-19 testing in the ED. Group 1 patients had reverse transcription polymerase chain reaction (RT-PCR) results obtained before CT scan reading (COVID-19 suspected on presentation); group 2 had RT-PCR results obtained after CT scans were read (COVID-19 not suspected). Presentation and imaging findings were compared, and outcomes were evaluated. Descriptive statistics and Fisher exact tests were used for analysis. Results Group 1 comprised 62 patients (31 men, 31 women; mean age, 67 years ±17 [standard deviation]), and group 2 comprised 57 patients (28 men, 29 women; mean age, 63 years ± 16). Cough and fever were more common in group 1 (37 of 62 [60%] and 29 of 62 [47%], respectively) than in group 2 (nine of 57 [16%] and 12 of 57 [21%], respectively), with no significant difference in the remaining symptoms. There were 101 CT scans of the abdomen or pelvis and 18 CT scans of the cervical spine or neck. In group 1, non-chest CT findings provided the initial evidence of COVID-19-related pneumonia in 32 of 62 (52%) patients. In group 2, the evidence was found in 44 of 57 (77%) patients. Overall, the most common CT findings were ground-glass opacity (114 of 119, 96%) and consolidation (47 of 119, 40%). Major interventions (vasopressor medication or intubation) were required for 29 of 119 (24%) patients, and 27 of 119 (23%) died. Patients who underwent CT of the cervical spine or neck had worse outcomes than those who underwent abdominal or pelvic CT (P = .01). Conclusion In a substantial percentage of patients with primary nonrespiratory symptoms who underwent non-chest CT, CT provided evidence of coronavirus disease 2019-related pneumonia. © RSNA, 2020.

Diagnostic Performance of Pulmonary Embolism Imaging in Patients with History of Asthma

Asthma and pulmonary embolism (PE) can present with overlapping symptoms, and distinguishing between these 2 conditions can be challenging. Asthma may limit imaging for PE because of either worsened ventilation defects on ventilation-perfusion scanning (VQ) or increased motion artifacts on CT pulmonary angiography (CTPA). Methods: We identified adults evaluated for PE with VQ or CTPA from 2012 to 2016. Patients with chronic lung disease (other than asthma) were excluded. Studies were classified as negative, positive, or nondiagnostic. Follow-up of negative cases was reviewed to determine the rate of repeat exams (within 1 wk) and the false-negative rate (defined as diagnosis of venous thromboembolism within 90 d). Results: We reviewed 19,412 adults (aged 52 ± 18 y, 70% women) evaluated for PE (60% with VQ, 40% with CTPA); 23% had a history of asthma. Nondiagnostic results were comparable for those with and without asthma for both VQ (asthma, 3.3%; nonasthma, 3.8%; P = 0.223) and CTPA (asthma, 1.6%; nonasthma, 1.5%; P = 0.891). A history of asthma was not associated with a higher rate of repeat exams after negative imaging for VQ (asthma, 1.9%; nonasthma, 2.1%; P = 0.547) or CTPA (asthma, 0.6%; nonasthma, 0.6%; P = 0.796), nor was a history of asthma associated with a higher false-negative rate for VQ (asthma, 0.4%; nonasthma, 0.9%; P = 0.015) or CTPA (asthma, 1.9%; nonasthma 1.5%; P = 0.347). Conclusion: A history of asthma in the preceding 10 y was not associated with impaired diagnostic performance of PE imaging for either VQ or CTPA.

The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society

With more than 900 000 confirmed cases worldwide and nearly 50 000 deaths during the first 3 months of 2020, the coronavirus disease 2019 (COVID-19) pandemic has emerged as an unprecedented health care crisis. The spread of COVID-19 has been heterogeneous, resulting in some regions having sporadic transmission and relatively few hospitalized patients with COVID-19 and others having community transmission that has led to overwhelming numbers of severe cases. For these regions, health care delivery has been disrupted and compromised by critical resource constraints in diagnostic testing, hospital beds, ventilators, and health care workers who have fallen ill to the virus exacerbated by shortages of personal protective equipment. Although mild cases mimic common upper respiratory viral infections, respiratory dysfunction becomes the principal source of morbidity and mortality as the disease advances. Thoracic imaging with chest radiography and CT are key tools for pulmonary disease diagnosis and management, but their role in the management of COVID-19 has not been considered within the multivariable context of the severity of respiratory disease, pretest probability, risk factors for disease progression, and critical resource constraints. To address this deficit, a multidisciplinary panel comprised principally of radiologists and pulmonologists from 10 countries with experience managing patients with COVID-19 across a spectrum of health care environments evaluated the utility of imaging within three scenarios representing varying risk factors, community conditions, and resource constraints. Fourteen key questions, corresponding to 11 decision points within the three scenarios and three additional clinical situations, were rated by the panel based on the anticipated value of the information that thoracic imaging would be expected to provide. The results were aggregated, resulting in five main and three additional recommendations intended to guide medical practitioners in the use of chest radiography and CT in the management of COVID-19.

The Role of Chest Imaging in Patient Management During the COVID-19 Pandemic: A Multinational Consensus Statement From the Fleischner Society

With more than 900,000 confirmed cases worldwide and nearly 50,000 deaths during the first 3 months of 2020, the coronavirus disease 2019 (COVID-19) pandemic has emerged as an unprecedented health care crisis. The spread of COVID-19 has been heterogeneous, resulting in some regions having sporadic transmission and relatively few hospitalized patients with COVID-19 and others having community transmission that has led to overwhelming numbers of severe cases. For these regions, health care delivery has been disrupted and compromised by critical resource constraints in diagnostic testing, hospital beds, ventilators, and health care workers who have fallen ill to the virus exacerbated by shortages of personal protective equipment. Although mild cases mimic common upper respiratory viral infections, respiratory dysfunction becomes the principal source of morbidity and mortality as the disease advances. Thoracic imaging with chest radiography and CT are key tools for pulmonary disease diagnosis and management, but their role in the management of COVID-19 has not been considered within the multivariable context of the severity of respiratory disease, pretest probability, risk factors for disease progression, and critical resource constraints. To address this deficit, a multidisciplinary panel comprised principally of radiologists and pulmonologists from 10 countries with experience managing patients with COVID-19 across a spectrum of health care environments evaluated the utility of imaging within three scenarios representing varying risk factors, community conditions, and resource constraints. Fourteen key questions, corresponding to 11 decision points within the three scenarios and three additional clinical situations, were rated by the panel based on the anticipated value of the information that thoracic imaging would be expected to provide. The results were aggregated, resulting in five main and three additional recommendations intended to guide medical practitioners in the use of chest radiography and CT in the management of COVID-19.

Implementation of an aortic dissection CT protocol with clinical decision support aimed at decreasing radiation exposure by reducing routine abdominopelvic imaging

Patients suspected of having an acute aortic syndrome in the ED typically undergo CT of the chest/abdomen/pelvis. However, the overwhelming majority of these exams are negative. With the help of clinical decision support, we implemented a new radiologist monitored 'aortic dissection screening protocol' that forgoes routine abdominopelvic imaging in order to reduce radiation dose without compromising diagnostic accuracy. The purpose of the present study is to assess the performance of this protocol. A retrospective analysis was performed to study the effect of the dissection screening protocol on the diagnostic yield, radiation and contrast dose on a total of 835 ED patients who underwent CT scans for suspected aortic dissection over a 48-week study period immediately before and after implementation of the protocol. 3.4% (28/835) of examinations were positive for an acute aortic syndrome over the 48-week study period with no difference in positivity before and after implementation of the 'aortic dissection screening' protocol, 3.0% vs. 3.7%, respectively (p = 0.57). There was a 14.6% reduction in median radiation dose and a 16% decrease in contrast volume utilization for the total ED population who underwent CT for aortic dissection using any protocol in the period after implementation of the 'aortic dissection screening' protocol. Aortic dissection CT in the ED is negative in the overwhelming majority of cases. A monitored 'aortic dissection screening' protocol that initially images the chest only significantly reduced contrast and radiation dose without reducing diagnostic accuracy for ED patients who underwent CT for aortic dissection.

Bovine Arch and Stroke Laterality

Background Left-hemispheric strokes are more frequent and often have a worse outcome than their right-hemispheric counterparts. This study aimed to evaluate whether cardioembolic stroke laterality is affected by anatomical characteristics of the aortic arch. We hypothesized that laterality varies between patients with bovine versus standard arch. Methods and Results We retrospectively identified 1598 acute cardioembolic strokes in patients with atrial fibrillation from our institutional stroke database (2009-2017). Inclusion criteria were acute anterior circulation ischemic infarct and availability of both arch and brain imaging (magnetic resonance imaging or computed tomography). Alternative causes of stroke and anomalous arch were excluded. Imaging was reviewed for stroke characterization and laterality and arch branching pattern. Bovine arch denotes a common origin of the brachiocephalic trunk and left common carotid artery. Strokes were classified as bilateral (left or right). Univariate analysis was performed using chi-square tests. The final cohort comprised 615 patients, mean age 77 years (SD 11.8 years) with 376 women (61%) and 33% white, 30% black, and the remainder mixed/Hispanic. Standard arch (n=424) stroke distribution was left 43.6% (185), right 45.1% (191), and bilateral 11.3% (48). Bovine arch (n=191) stroke distribution was left 51.3% (98), right 35.6% (68), and bilateral 13.1% (25). Bovine arches were associated with more left-sided strokes compared with standard arches (P=0.018). There was an association between black race and bovine arch (P=0.0001). Conclusions Bovine aortic arch configuration is associated with left hemispheric laterality of cardioembolic stroke. This study enriches the understanding that arch anatomy influences stroke laterality and highlights the need for further research into the causative hemodynamic factors.

Imaging of Chronic Thromboembolic Disease

Acute pulmonary embolism (PE) is a leading cause of cardiovascular morbidity. The most common long-term complication of acute PE is chronic thromboembolic disease, a heterogenous entity which ranges from asymptomatic imaging sequelae to persistent symptoms. Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease that can develop in this population and represents the only treatable type of pulmonary hypertension. Recognition of the characteristic findings of chronic pulmonary embolism and CTEPH provides not only diagnostic information, but is also crucial for guiding therapy. The present state-of-the-art review focuses on the multimodality imaging features of chronic pulmonary embolism. Detailed description and illustrations of relevant imaging findings will be demonstrated for ventilation/perfusion (V/Q) scan, CT scan and Dual-Energy CT and MRI and features that distinguish chronic PE from common imaging mimics.

Performance of the Vancouver Risk Calculator Compared with Lung-RADS in an Urban, Diverse Clinical Lung Cancer Screening Cohort

PURPOSE

To compare the performance of the Vancouver risk calculator (VRC) with the American College of Radiology's Lung CT Screening Reporting and Data System (Lung-RADS) for a lung cancer screening cohort in an urban, diverse clinical setting.

MATERIALS AND METHODS

This study included a total of 486 patients with lung nodules (63 years ± 5.2 [standard deviation], 261 female patients), 448 of whom had lung nodules that were subsequently classified as benign and 38 of whom had those that were classified as malignant. The mean follow-up time was 40.0 months ± 14. Institutional review board approval was obtained for this Health Insurance Portability and Accountability Act-compliant retrospective study, and a waiver of informed consent was received. All patients undergoing lung cancer screening who underwent an initial baseline screening CT between December 2012 and June 2016 that demonstrated a nodule and had at least 1 year of follow-up comprised the study population. Each examination was assigned a Lung-RADS score between 2 and 4B, with 4A and 4B considered as showing positive results. The VRC calculates the risk of cancer at different thresholds using nine variables related to patient and imaging characteristics. Analysis was performed per patient based on the largest nodule. Lung-RADS and VRC using the 5% threshold were compared to assess diagnostic performance in determining the risk of developing lung cancer in a patient with a nodule found at screening CT. The McNemar test was used to compare differences in performance between Lung-RADS and VRC.

RESULTS

Lung-RADS resulted in nine false-positive and 16 false-negative findings, whereas VRC with a 5% threshold resulted in 29 false-positive and 10 false-negative findings. Overall sensitivity and specificity for Lung-RADS was 58.0% and 98.0%, and for VRC with a 5% threshold was 73.7% and 93.5%, respectively (P = .313, P < .001, respectively).

CONCLUSION

The VRC performs well in an urban, diverse lung cancer screening program. Further studies may be directed at determining whether its use in conjunction with Lung-RADS leads to improved lung cancer detection.Keywords: CT, Lung, Thorax© RSNA, 2020.

The relationship between adrenal incidentalomas and mortality risk

OBJECTIVE

To determine all-cause mortality risk in patients with and without adrenal incidentaloma.

METHODS

Retrospective cohort study of patients with CT abdomen performed within 24 h of emergency room presentation at an academic medical center from January 1, 2005, to December 31, 2009, without history of adrenal disease, adrenal lab testing, or cancer. Incidentaloma cohort identified by database query of imaging reports followed by manual review and matched to no-nodule controls at 3:1 on age ± 1 year and exam date ± 3 months. Mortality ascertained by in-hospital deaths and National Death Index query. Survival analysis performed with Kaplan-Meier curves and Cox proportional hazards models.

RESULTS

Among 42,575 adults with abdominal CT exams, 969 adrenal incidentaloma patients and 2907 no-nodule controls were identified. All 3876 individuals entered survival analysis with 31,182 person-years at risk (median follow-up 8.9 years [IQR, 6.9-10.7]). All-cause mortality was significantly higher among those with adrenal incidentalomas (353/969, 36.4%) compared with those without (919/2907, 31.6%; mortality difference 7.6 per 1000 person-years; multivariable-adjusted hazard ratio [aHR] 1.14; 95% CI, 1.003-1.29). Exploratory analyses, limited by missing covariates, found that adrenal incidentalomas were associated with significantly increased incidence of malignancy (aHR 1.61; 95% CI, 1.22-2.12), diabetes (aHR 1.43; 95% CI, 1.18-1.71), heart failure (aHR 1.32; 95% CI, 1.07-1.63), peripheral vascular disease (aHR 1.28; 95% CI, 1.95-1.56), renal disease (aHR 1.21; 95% CI, 1.01-1.44), and chronic pulmonary disease (aHR 1.22; 95% CI, 1.01-1.46) compared with controls.

CONCLUSIONS

Adrenal incidentalomas are associated with increased mortality and may represent a clinically valuable biomarker.

KEY POINTS

• Adrenal incidentalomas are associated with increased mortality. • Adrenal incidentaloma size is not predictive of mortality. • On exploratory analyses, adrenal incidentalomas are associated with chronic illnesses.

Vancouver Risk Calculator Compared with ACR Lung-RADS in Predicting Malignancy: Analysis of the National Lung Screening Trial

Purpose To compare the Vancouver risk calculator (VRC) with American College of Radiology (ACR) Lung Imaging Reporting and Data System (Lung-RADS) in predicting the risk of malignancy in the National Lung Screening Trial (NLST). Materials and Methods A total of 2813 patients with 4408 nodules (4078 solid, 330 subsolid) were available from the NLST for evaluation. Nodules were scored by using VRC with nine parameters (output was the percentage likelihood of malignancy; VRC threshold for malignancy likelihood set as greater than 5%) and Lung-RADS (output was category 2-4B; malignancy defined as category 4A or 4B; malignancy likelihood greater than 5%). Lung-RADS and VRC were compared for sensitivity, specificity, and accuracy for malignancy on a per-nodule and per-patient basis. Results Of 4408 total nodules, 100 of 4078 (2.5%) solid nodules were malignant and 10 of 330 (3%) subsolid nodules were malignant. On an overall per-nodule basis, the sensitivity, specificity, and accuracy for VRC and Lung-RADS were 93%, 90%, and 90% for VRC and 87%, 83%, and 83% for Lung-RADS, respectively (P = .077, P < .001, and P < .001, respectively). On a per-patient basis, the sensitivity, specificity, and accuracy for VRC and Lung-RADS were 93%, 85%, and 85% for VRC and 87%, 76%, and 76% for Lung-RADS, respectively (P = .077, P < .001, and P < .001, respectively). Conclusion The Vancouver risk calculator had superior overall accuracy than the Lung Imaging Reporting and Data System in predicting malignancy in the National Lung Screening Trial for total nodules, as well as on a per-patient basis. © RSNA, 2019 See also the editorial by Black in this issue.

Starfish in the heart: Congenital anomaly of the papillary muscles

Most common congenital anatomical abnormalities of the subvalvular apparatus (papillary muscles and chordae tendineae) are parachute or parachute like mitral valve. This is more commonly reported among the pediatric population as they develop heart failure symptoms shortly after birth. Reports of adult cases are rare and incidental. Multimodality imaging has an important role in evaluating such anatomical abnormalities, and identification of possible related complications. We are describing a rare atypical variant of parachute like mitral valve.

Imaging of suspected pulmonary embolism and deep venous thrombosis in obese patients

Obesity is a growing problem around the world, and radiology departments frequently encounter difficulties related to large patient size. Diagnosis and management of suspected venous thromboembolism, in particular deep venous thrombosis (DVT) and pulmonary embolism (PE), are challenging even in some lean patients, and can become even more complicated in the setting of obesity. Many obstacles must be overcome to obtain imaging examinations in obese patients with suspected PE and/or DVT, and to ensure that these examinations are of sufficient quality to diagnose or exclude thromboembolic disease, or to establish an alternative diagnosis. Equipment limitations and technical issues both need to be acknowledged and addressed. Table weight limits and scanner sizes that readily accommodate obese and even morbidly obese patients are not in place at many clinical sites. There are also issues with image quality, which can be substantially compromised. We discuss current understanding of the effects of patient size on imaging in general and, more specifically, on the imaging modalities used for the diagnosis and treatment of DVT and PE. Emphasis will be placed on the technical parameters and protocol nuances, including contrast dosing, which are necessary to refine and optimize images for the diagnosis of DVT and PE in obese patients, while remaining cognizant of radiation exposure. More research is necessary to develop consistent high-level evidence regarding protocols to guide radiologists, and to help them effectively utilize emerging technology.

Screening Patterns and Mortality Differences in Patients With Lung Cancer at an Urban Underserved Community

BACKGROUND

The landmark National Lung Screening Trial demonstrated significant reduction in lung cancer-related mortality. However, European lung cancer screening (LCS) trials have not confirmed such benefit. We examined LCS patterns and determined the impact of LCS-led diagnosis on the mortality of newly diagnosed patients with lung cancer in an underserved community.

PATIENTS AND METHODS

Medical records of patients diagnosed with primary lung cancer in 2013 through 2016 (n = 855) were reviewed for primary care provider (PCP) status and LCS eligibility and completion, determined using United States Preventative Services Task Force guidelines. Univariate analyses of patient characteristics were conducted between LCS-eligible patients based on screening completion. Survival analyses were conducted using Kaplan-Meier and multivariate Cox regression.

RESULTS

In 2013 through 2016, 175 patients with primary lung cancer had an established PCP and were eligible for LCS. Among them, 19% (33/175) completed screening prior to diagnosis. LCS completion was associated with younger age (P = .02), active smoking status (P < .01), earlier stage at time of diagnosis (P < .01), follow-up in-network cancer treatment (P = .03), and surgical management (P < .01). LCS-eligible patients who underwent screening had improved all-cause mortality compared with those not screened (P < .01). Multivariate regression showed surgery (hazard ratio, 0.31; P = .04) significantly affected mortality.

CONCLUSION

To our knowledge, this is the first study to assess LCS patterns and mortality differences on patients with screen-detected lung cancer in an urban underserved setting since the inception of United States Preventative Services Task Force guidelines. Patients with a LCS-led diagnosis had improved mortality, likely owing to cancer detection at earlier stages with curative treatment, which echoes the finding of prospective trials.

Cardiothoracic MRI in the ICU: A 10-Year Experience

RATIONALE AND OBJECTIVE

The objective of this study was to identify the feasibility and pitfalls of cardiothoracic magnetic resonance imaging (MRI) in intensive care unit (ICU) patients.

MATERIALS AND METHODS

This retrospective study identified adult ICU patients scheduled for cardiothoracic MRIs during a 10-year study period. ICU patients scheduled for brain MRIs served as a comparison group. A chart review was performed to identify factors impacting a patient's ability to undergo an MRI. Differences between completed and canceled examinations for both cardiothoracic and brain MRIs were evaluated. For the cardiothoracic group, clinical indications and the diagnostic value of the study performed were also identified.

RESULTS

A total of 143 cardiothoracic MRIs and 1011 brain MRIs were requested. Cardiothoracic MRI patients were less frequently completed (52% vs 62%), more frequently men (64% vs 43%), younger (55 vs 63 years), less likely mechanically ventilated (8% vs 29%), more likely to require intravenous contrast (83% vs 23%), and had longer examination times compared to brain MRI patients (64 vs 21 minutes). Successful completion of cardiothoracic MRI was associated with lower serum creatinine, higher glomerular filtration rate, and the absence of mechanical ventilation; significant differences were not seen with regard to gender and use of vasoactive agents. Cardiothoracic MRI results were diagnostic in 69% of examinations, most frequently when performed for myocardial disease (84%) and aortic disease (33%), and less frequently for viability (33%).

CONCLUSIONS

In an ICU population, successful completion of cardiothoracic MRI is challenging but feasible in patients with intact renal function and the absence of mechanical ventilation. Examinations were most frequently diagnostic for myocardial and aortic disease indications.

Imaging for Pulmonary Embolism in Sickle Cell Disease: A 17-Year Experience

Sickle cell disease, a complex disorder with known pulmonary complications, has the potential to confound the diagnosis of pulmonary embolism. We hypothesized that when the choice of imaging is guided by chest radiographic results, CT pulmonary angiography (CTPA) and ventilation-perfusion (V/Q) scintigraphy have comparable diagnostic performance in sickle cell disease. Methods: A retrospective cohort of adults with sickle cell disease who were imaged for suspected pulmonary embolism with either CTPA or V/Q, from 2000 to 2016 at our institution, was established. To reduce radiation exposure, our practice recommends V/Q for stable patients with normal chest radiographs. Results of index pulmonary embolism imaging, 90-d follow-up, and results of chest radiography were recorded. Results: Two hundred forty-five adults with sickle cell disease comprised the cohort. The mean age (±SD) was 33 ± 10.5 y, and 58% (141) were men. Index imaging was V/Q in 62.9% (n = 154) and CTPA in 37.1% (n = 91). Chest radiographs, performed in 96.3% (n = 236), were normal in 72.9% (n = 172). Imaging results for pulmonary embolism were negative in 88.2% (n = 216), positive in 4.1% (n = 10), and indeterminate in 7.8% (n = 19) with no difference between V/Q and CTPA (P = 0.63). Reimaging within 90 d occurred in 9.8% (n = 24), 14.7% (20/136) after initial V/Q, and 5% (4/109) after initial CTPA (P = 0.08). Reimaging revealed a pulmonary embolism diagnosis after negative/indeterminate results in 0.7% (1/149) of V/Qs and 1.2% of (1/86) CTPAs (P = 0.69). Over the 17-y study period, 47% (114/245) underwent repeated imaging, and 11% (27/245) were diagnosed with pulmonary embolism at least once. Conclusion: In sickle cell disease patients with suspected pulmonary embolism, positive imaging rates were low for any given clinical presentation, but 11% of the cohort was diagnosed with pulmonary embolism over the 17-y study period. CTPA and V/Q performed comparably for pulmonary embolism diagnosis when the choice of imaging was guided by results of chest radiography. Hence, V/Q is a reasonable first choice for sickle cell disease patients with normal chest radiographs.

Circumferential strain acquired by CMR early after acute myocardial infarction adds incremental predictive value to late gadolinium enhancement imaging to predict late myocardial remodeling and subsequent risk of sudden cardiac death

PURPOSE

Late adverse myocardial remodeling after acute myocardial infarction (AMI) is strongly associated with sudden cardiac death (SCD). Cardiac magnetic resonance (CMR) performed early after AMI can predict late remodeling and SCD risk with moderate accuracy. This study assessed the ability of CMR-measured circumferential strain (CS) to add incremental predictive information to late gadolinium enhancement (LGE).

METHODS

Patients with an AMI and LVEF < 50% were screened for inclusion. A total of 27 patients, totaling 432 myocardial segments, prospectively underwent CMR 7 ± 5 days after percutaneous coronary intervention (PCI). LGE, microvascular obstruction (MVO), and myocardial CS were measured for each segment. The primary endpoint was late segmental adverse remodeling defined as segmental wall motion score (WMS) > 1 measured by echocardiography 3 months after PCI.

RESULTS

A total of 141 segments experienced the primary endpoint at 3 months. The mean LGE volume was higher in these segments, but LGE was also present in many segments with normal WMS (40 ± 28 versus 20 ± 26%, p < 0.01). Segments that met the primary endpoint also showed greater impairment of CS. Segments with both LGE > 17% and impaired CS >- 7.2% on CMR were more likely to experience late adverse remodeling (73%) as compared to segments with neither (9%, p < 0.001) or one abnormal parameter (36%, p < 0.001). CS >- 7.2% also added incremental accuracy to LGE > 17% for predicting late adverse remodeling (AUC 0.81 from 0.70, p < 0.001).

CONCLUSIONS

When performed early after AMI, LGE is a moderate predictor of late remodeling and CS is a powerful predictor of late myocardial remodeling. When combined, they can predict late remodeling, a surrogate of SCD, with high accuracy.

Performance of a simple robust empiric timing protocol for CT pulmonary angiography

OBJECTIVE

We instituted a new, simple CT pulmonary angiography (CTPA) contrast material timing protocol using a standard empiric delay to replace our previous timing bolus method. This study tests the hypothesis that the empiric protocol more consistently produces diagnostic quality images of both the pulmonary arteries and the aorta with lower radiation exposure.

MATERIALS AND METHODS

We performed a retrospective review of consecutive CTPAs for 2months both before and after the protocol change. Pulmonary artery and aortic enhancement, patient characteristics, radiation exposure and results of CTPA were analyzed.

RESULTS

There were 182 patients in the timing bolus group and 164 in the empiric timing group. Both groups had a female majority (59%) and a similar mean age (58 and 57years, respectively). Enhancement was significantly higher both for the pulmonary artery (median 400HU versus 359HU, P<0.001) and aorta (median 381HU versus 218HU, P<0.01) in the empiric timing group versus the timing bolus group, respectively. Radiation exposure was lower (5.3mSv versus 6.0mSv, P=0.05) in the empiric timing group, despite a higher body-mass-index (31 versus 29kg/m², P<0.01). Pulmonary embolism positivity rate was non-significantly higher in the timing bolus vs the empiric timing group (19% and 13%, P=0.1).

CONCLUSION

A simple empiric timing protocol for CTPA has robust performance compared to a timing bolus protocol. Empiric timing preserves the required high diagnostic quality for evaluation of the pulmonary arteries with the added benefits of aortic enhancement and lower radiation exposure.

Performance of Low-Dose Perfusion Scintigraphy and CT Pulmonary Angiography for Pulmonary Embolism in Pregnancy

BACKGROUND

The symptoms of normal pregnancy overlap those of pulmonary embolism (PE). Limited literature suggests that low-dose perfusion scanning (LDQ), which yields lower maternal-fetal radiation exposure than CT pulmonary angiography (CTPA), performs well in excluding PE in pregnant patients.

METHODS

We performed a retrospective cohort study of sequential pregnant women who underwent imaging for PE with LDQ or CTPA between 2008 and 2013 at Montefiore Medical Center. Our practice recommends LDQ for patients with negative results on chest radiographs. Patients were categorized according to initial imaging modality, and a subgroup analysis was performed in patients with asthma. The primary outcome was the negative predictive value (NPV) of imaging determined by VTE diagnosis within 90 days.

RESULTS

Of 322 pregnant women (mean age, 27.3 ± 6.3 years), initial imaging was positive for PE in 2.7% (6 of 225) of LDQs and 4.1% (4 of 97) of CTPAs, negative in 88.0% (198 of 225) of LDQs and 86.6% (84 of 97) of CTPAs, and indeterminate/nondiagnostic in 9.3% (21 of 225) of LDQs and 9.3% (9 of 97) of CTPAs (P = .79). Ten patients (3.1%) were treated for PE. The NPV was 100% for LDQ and 97.5% for CTPA. Subgroup analysis of patients with asthma (23.9% of this population) revealed a high likelihood of a negative study in the LDQ and CTPA groups (74.1% and 87.0%, respectively) and 100% NPV for both modalities.

CONCLUSIONS

PE is an uncommon diagnosis in pregnancy. LDQ and CTPA perform well, with less maternal-fetal radiation exposure with LDQ. Therefore, when available, LDQ is a reasonable first-choice modality for suspected PE in pregnant women with a negative result on chest radiograph.

Thoracic Imaging Features of Legionnaire's Disease

Imaging examinations are often performed in patients with Legionnaires' disease. The literature to date has documented that the imaging findings in this disorder are relatively nonspecific, and it is therefore difficult to prospectively differentiate legionella pneumonia from other forms of pneumonia, and from other noninfectious thoracic processes. Through a review of clinical cases and the literature, our objective is for the reader to gain a better understanding of the spectrum of radiographic manifestations of Legionnaires' disease.

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.

ACR White Paper-Based Comprehensive Dose Reduction Initiative Is Associated With a Reversal of the Upward Trend in Radiation Dose for Chest CT

PURPOSE

In 2010, the authors' department implemented a comprehensive dose reduction strategy based on the ACR white paper on radiation dose in medicine. The aim of this study was to evaluate the effectiveness of the dose reduction program.

METHODS

In total, 1,234 adult chest CT scans from 2007 to 2012 were analyzed retrospectively, with institutional review board approval and a waiver of the requirement for informed consent. The primary outcome was effective dose in millisieverts during the three-year periods before (2007-2009) and after (2010-2012) dose reduction implementation. Dose trends were analyzed by fitted linear modeling. The use and effects on total exposure of dose reduction strategies (high pitch, adaptive statistical iterative reconstruction [ASIR], and low tube voltage) were analyzed.

RESULTS

The overall mean dose for chest CT was 7.3 ± 5.1 mSv. The mean dose decreased by 30%, from 9.2 mSv (2007-2009) to 6.5 mSv (2010-2012) (P < .001). From 2007 to 2009, the mean dose increased by 1.2 mSv per year (P < .01). From 2010 to 2012, the mean dose decreased by 1.1 mSv per year (P < 0.01). High-pitch technique, ASIR, and low tube voltage increased significantly after dose reduction implementation. High pitch and ASIR were significantly associated with a reduced dose, whereas the effect of reduced voltage was not significant.

CONCLUSIONS

Reductions in radiation exposure from medical imaging rely on ongoing technical developments and consistent, vigilant use of dose reduction strategies. This comprehensive dose reduction strategy significantly reduced radiation exposure from chest CT. Annual increases in radiation dose reversed after the strategy was implemented and continued to decline over the study period.

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.