Training and Verification Requirements for Interpretation of Cardiac CT and MRI: AJR Expert Panel Narrative Review.

The use of cardiac CT and MRI is rapidly expanding based on strong evidence from large international trials. The number of physicians competent to interpret cardiac CT and MRI may be unable to keep pace with the increasing demand. Societies and organizations have prescribed training requirements for interpreting cardiac CT and MRI, with recent updates focusing on the increased breadth of competency that is now required due to ongoing imaging advances. In this AJR Expert Panel Narrative Review, we discuss several aspects of cardiac CT and MRI training, focusing on topics that are uncertain or not addressed in existing society statements and guidelines, including determination of competency in different practice types in real-world settings and the impact of artificial intelligence on training and education. The article is intended to guide updates in professional society training requirements and also inform institutional verification processes.

Spontaneous coronary artery dissection and its association with takotsubo syndrome: Novel insights from a tertiary center registry.

BACKGROUND: Spontaneous coronary artery dissection (SCAD) is a relatively rare cause of acute coronary syndrome historically thought to primarily affect young, healthy women. The lack of multicenter collaborative research efforts has made it challenging to identify the precise etiology and pathological mechanisms underlying SCAD. However, there are many similarities in the patient demographics, clinical presentations, and predisposing stressors between SCAD and takotsubo syndrome (TTS). OBJECTIVES: The aim of this observational study was to examine the coronary and left ventriculographic features of patients with angiographically confirmed SCAD and determine the prevalence of concomitant TTS. METHODS: In this observational study, patients with angiographically confirmed SCAD were identified from the Massachusetts General Hospital SCAD registry. The coronary angiograms with simultaneous left ventriculograms (LVG) were carefully analyzed by an independent and blinded angiographic core laboratory. RESULTS: From our analysis of patients with SCAD who also underwent a LVG at time of coronary angiography, we identified a high prevalence of SCAD and concomitant TTS. CONCLUSIONS: Therefore, we present TTS as a plausible mechanistic etiology for SCAD in some patients. In light of this finding as well as the many similarities between SCAD and TTS, clinicians should be vigilant about the potential concomitant presence of these two entities. Additional future investigations further exploring the clinical implications of the association between SCAD and TTS are warranted.

Left ventricular wall thickness assessed by cardiac computed tomography and cardiac resynchronization therapy outcomes.

AIMS: Up to 30% of selected heart failure patients do not benefit clinically from cardiac resynchronization therapy (CRT). Left ventricular (LV) wall thickness (WT) analysed using computed tomography (CT) has rarely been evaluated in response to CRT and mitral regurgitation (MR) improvement. We examined the association of LVWT and the ability to reverse LV remodelling and MR improvement after CRT. METHODS AND RESULTS: Fifty-four patients scheduled for CRT underwent pre-procedural CT. Reduced LVWT was defined as WT <6 mm and quantified as a percentage of total LV area. Endpoints were 6-month clinical and echocardiographic response to CRT [New York Heart Association (NYHA) class, LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), and LV end-systolic volume (LVESV)], MR improvement and 2-year major adverse cardiac events (MACE). Patients were divided into three groups according to the percentage of LVWT <6 mm area: ≤20%, 20-50%, and ≥50%. At 6 months, 75%, 71%, and 42% of the patients experienced NYHA improvement in the ≤20%, 20-50%, and ≥50% group, respectively. Additionally, ≤20% group presented higher LVEF, LVEDV, and LVESV positive response rate (86%, 59%, and 83%, respectively). Both 20-50% and ≥50% groups exhibited a lower LVEF, LVEDV, and LVESV positive response rate (52% and 42%; 47% and 45%; and 53% and 45%, respectively). Additionally, ≥25% of LVWT <6 mm inclusive of at least one papillary muscle insertion was the only predictor of lack of MR improvement. Lastly, ≥50% group experienced significantly lower 2-year MACE survival free probability. CONCLUSION: WT evaluated using CT could help to stratify the response to CRT and predict MR improvement and outcomes. CLINICAL TRIAL REGISTRATION: NCT01097733.

A comparison of postprocedural anticoagulation in high-risk patients undergoing WATCHMAN device implantation.

BACKGROUND: Left atrial appendage closure (LAAC) is an alternative to long-term anticoagulation for thromboembolic protection in patients with atrial fibrillation (AF) and high bleeding risk. Short-term Warfarin use following LAAC is well-studied, while data pertaining to novel oral anticoagulant (NOAC) use in this setting is less robust. Specifically, data regarding the safety and efficacy of postprocedural NOAC use in high-risk patients is lacking. OBJECTIVE: To compare the safety and efficacy of Warfarin and NOAC use in a high-risk patient population undergoing LAAC with the WATCHMAN device. METHODS: From November 2015 to October 2017, 97 patients underwent LAAC with the WATCHMAN device. All patients were discussed at a multidisciplinary meeting prior to device implantation. Longitudinal data were collected and analyzed for a composite endpoint of stroke and death at 8 months, and major bleeding at 3 and 6 months. RESULTS: Among the 90 patients included in the safety and efficacy analysis, 43 were prescribed Warfarin and 47 were prescribed NOACs. Baseline characteristics were comparable between study groups. There were no procedural complications and no significant differences in the incidence of death and stroke at 8 months or major bleeding at 3 and 6 months. CONCLUSION: For patients with AF at high risk of both thromboembolic and hemorrhagic events, NOACs as compared to Warfarin, seem to be safe and effective for short-term anticoagulation following LAAC with the WATCHMAN device. Further validation in large randomized controlled trials is required.

Perivascular Epicardial Fat Stranding at Coronary CT Angiography: A Marker of Acute Plaque Rupture and Spontaneous Coronary Artery Dissection.

Purpose To evaluate the frequency and implications of perivascular fat stranding on coronary computed tomography (CT) angiograms obtained for suspected acute coronary syndrome (ACS). Materials and Methods This retrospective registry study was approved by the institutional review board. The authors reviewed the medical records and images of 1403 consecutive patients (796 men, 607 women; mean age, 52.8 years) who underwent coronary CT angiography at the emergency department from February 2012 to March 2016. Fat attenuation, length and number of circumferential quadrants of the affected segment, and attenuation values in the unaffected epicardial and subcutaneous fat were measured. "Cases" were defined as patients with perivascular fat stranding. Patients with significant stenosis but without fat stranding were considered control subjects. Baseline imaging characteristics, ACS frequency, and results of subsequent downstream testing were compared between cases and control subjects by using two-sample t, Mann-Whitney U, and Fisher tests. Results Perivascular fat stranding was seen in 11 subjects, nine with atherosclerotic lesions and two with spontaneous coronary artery dissections, with a mean fat stranding length of 19.2 mm and circumferential extent averaging 2.9 quadrants. The mean attenuation of perivascular fat stranding, normal epicardial fat, and normal subcutaneous fat was 17, -93.2, and -109.3 HU, respectively (P < .001). Significant differences (P < .05) between cases and control subjects included lower Agatston score, presence of wall motion abnormality, and initial elevation of serum troponin level. ACS frequency was 45.4% in cases and 3.8% in control subjects (P = .001). Conclusion Recognition of perivascular fat stranding may be a helpful additional predictor of culprit lesion and marker of risk for ACS in patients with significant stenosis or spontaneous coronary artery dissection. © RSNA, 2018 Online supplemental material is available for this article.

Central Core Laboratory versus Site Interpretation of Coronary CT Angiography: Agreement and Association with Cardiovascular Events in the PROMISE Trial.

Purpose To assess concordance and relative prognostic utility between central core laboratory and local site interpretation for significant coronary artery disease (CAD) and cardiovascular events. Materials and Methods In the Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE) trial, readers at 193 North American sites interpreted coronary computed tomographic (CT) angiography as part of the clinical evaluation of stable chest pain. Readers at a central core laboratory also interpreted CT angiography blinded to clinical data, site interpretation, and outcomes. Significant CAD was defined as stenosis greater than or equal to 50%; cardiovascular events were defined as a composite of cardiovascular death or myocardial infarction. Results In 4347 patients (51.8% women; mean age ± standard deviation, 60.4 years ± 8.2), core laboratory and site interpretations were discordant in 16% (683 of 4347), most commonly because of a finding of significant CAD by site but not by core laboratory interpretation (80%, 544 of 683). Overall, core laboratory interpretation resulted in 41% fewer patients being reported as having significant CAD (14%, 595 of 4347 vs 23%, 1000 of 4347; P < .001). Over a median follow-up period of 25 months, 1.3% (57 of 4347) sustained myocardial infarction or cardiovascular death. The C statistic for future myocardial infarction or cardiovascular death was 0.61 (95% confidence interval [CI]: 0.54, 0.68) for the core laboratory and 0.63 (95% CI: 0.56, 0.70) for the sites. Conclusion Compared with interpretation by readers at 193 North American sites, standardized core laboratory interpretation classified 41% fewer patients as having significant CAD. © RSNA, 2017 Online supplemental material is available for this article. Clinical trial registration no. NCT01174550.

Effect of Omega-3 Acid Ethyl Esters on Left Ventricular Remodeling After Acute Myocardial Infarction: The OMEGA-REMODEL Randomized Clinical Trial.

BACKGROUND: Omega-3 fatty acids from fish oil have been associated with beneficial cardiovascular effects, but their role in modifying cardiac structures and tissue characteristics in patients who have had an acute myocardial infarction while receiving current guideline-based therapy remains unknown. METHODS: In a multicenter, double-blind, placebo-controlled trial, participants presenting with an acute myocardial infarction were randomly assigned 1:1 to 6 months of high-dose omega-3 fatty acids (n=180) or placebo (n=178). Cardiac magnetic resonance imaging was used to assess cardiac structure and tissue characteristics at baseline and after study therapy. The primary study endpoint was change in left ventricular systolic volume index. Secondary endpoints included change in noninfarct myocardial fibrosis, left ventricular ejection fraction, and infarct size. RESULTS: By intention-to-treat analysis, patients randomly assigned to omega-3 fatty acids experienced a significant reduction of left ventricular systolic volume index (-5.8%, P=0.017), and noninfarct myocardial fibrosis (-5.6%, P=0.026) in comparison with placebo. Per-protocol analysis revealed that those patients who achieved the highest quartile increase in red blood cell omega-3 index experienced a 13% reduction in left ventricular systolic volume index in comparison with the lowest quartile. In addition, patients in the omega-3 fatty acid arm underwent significant reductions in serum biomarkers of systemic and vascular inflammation and myocardial fibrosis. There were no adverse events associated with high-dose omega-3 fatty acid therapy. CONCLUSIONS: Treatment of patients with acute myocardial infarction with high-dose omega-3 fatty acids was associated with reduction of adverse left ventricular remodeling, noninfarct myocardial fibrosis, and serum biomarkers of systemic inflammation beyond current guideline-based standard of care. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00729430.

Case records of the Massachusetts General Hospital. Case 35-2014: a 31-year-old woman with fevers, chest pain, and a history of HCV infection and substance-use disorder.

A 31-year-old woman with substance-use disorder was admitted to this hospital because of fevers and chest pain. CT of the chest revealed multiple thick-walled nodular opacities throughout both lungs. Diagnostic tests were performed, and management decisions were made.

Obesity, metabolic syndrome and cardiovascular prognosis: from the Partners coronary computed tomography angiography registry.

OBJECTIVE: To investigate the relationship among body mass index (BMI), cardiometabolic risk and coronary artery disease (CAD) among patients undergoing coronary computed tomography angiography (CTA). METHODS: Retrospective cohort study of 1118 patients, who underwent coronary CTA at two centers from September 2004 to October 2011. Coronary CTA were categorized as normal, nonobstructive CAD (<50%), or obstructive CAD (≥50%) in addition to segment involvement (SIS) and stenosis scores. Extensive CAD was defined as SIS > 4. Association of BMI with cardiovascular prognosis was evaluated using multivariable fractional polynomial models. RESULTS: Mean age of the cohort was 57 ± 13 years with median follow-up of 3.2 years. Increasing BMI was associated with MetS (OR 1.28 per 1 kg/m2, p < 0.001) and burden of CAD on a univariable basis, but not after multivariable adjustment. Prognosis demonstrated a J-shaped relationship with BMI. For BMI from 20-39.9 kg/m2, after adjustment for age, gender, and smoking, MetS (HR 2.23, p = 0.009) was more strongly associated with adverse events. CONCLUSIONS: Compared to normal BMI, there was an increased burden of CAD for BMI > 25 kg/m2. Within each BMI category, metabolically unhealthy patients had greater extent of CAD, as measured by CCTA, compared to metabolically healthy patients.

Cervical artery dissection expands the cardiovascular phenotype in FBN1-related Weill-Marchesani syndrome.

Weill-Marchesani syndrome (WMS) is a rare form of acromelic dysplasia that is characterized by distinctive skeletal, ocular, and cardiovascular abnormalities. Previously described cardiac manifestations of WMS include aortic and pulmonary valve stenosis, mitral valve prolapse, mitral stenosis, and QTc prolongation. Autosomal dominant forms of WMS result from heterozygous pathogenic variants in FBN1, a gene with a well characterized role in the pathogenesis of thoracic aortic aneurysm (TAA) in the context of Marfan syndrome. In contrast, only one patient has been reported with aortic disease in WMS. Although the risk of aortic dissection from preceding TAA remains the leading cause of morbidity for individuals with Marfan syndrome, rare reports of arterial dissection in the peripheral vasculature have been described. Peripheral artery dissection has not been previously reported in other FBN1-related diseases. We describe a three generation family with FBN1-related WMS whose cardiovascular manifestations include TAA and cervical artery dissection, thus expanding the cardiovascular phenotype of WMS. Further research is required to quantify these risks and establish appropriate recommendations for cardiovascular imaging, medical management, and prophylactic surgical intervention in individuals with FBN1--related acromelic dysplasia.

Real-time fusion of coronary CT angiography with x-ray fluoroscopy during chronic total occlusion PCI.

OBJECTIVES: The purpose of this study was to demonstrate the feasibility of real-time fusion of coronary computed tomography angiography (CTA) centreline and arterial wall calcification with x-ray fluoroscopy during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). METHODS: Patients undergoing CTO PCI were prospectively enrolled. Pre-procedural CT scans were integrated with conventional coronary fluoroscopy using prototype software. We enrolled 24 patients who underwent CTO PCI using the prototype CT fusion software, and 24 consecutive CTO PCI patients without CT guidance served as a control group. RESULTS: Mean age was 66 ± 11 years, and 43/48 patients were men. Real-time CTA fusion during CTO PCI provided additional information regarding coronary arterial calcification and tortuosity that generated new insights into antegrade wiring, antegrade dissection/reentry, and retrograde wiring during CTO PCI. Overall CTO success rates and procedural outcomes remained similar between the two groups, despite a trend toward higher complexity in the fusion CTA group. CONCLUSIONS: This study demonstrates that real-time automated co-registration of coronary CTA centreline and calcification onto live fluoroscopic images is feasible and provides new insights into CTO PCI, and in particular, antegrade dissection reentry-based CTO PCI. KEY POINTS: • Real-time semi-automated fusion of CTA/fluoroscopy is feasible during CTO PCI. • CTA fusion data can be toggled on/off as desired during CTO PCI • Real-time CT calcium and centreline overlay could benefit antegrade dissection/reentry-based CTO PCI.

Clinical implementation of an emergency department coronary computed tomographic angiography protocol for triage of patients with suspected acute coronary syndrome.

OBJECTIVES: To evaluate the efficiency and safety of emergency department (ED) coronary computed tomography angiography (CTA) during a 3-year clinical experience. METHODS: Single-center registry of coronary CTA in consecutive ED patients with suspicion of acute coronary syndrome (ACS). The primary outcome was efficiency of coronary CTA defined as the length of hospitalization. Secondary endpoints of safety were defined as the rate of downstream testing, normalcy rates of invasive coronary angiography (ICA), absence of missed ACS, and major adverse cardiac events (MACE) during follow-up, and index radiation exposure. RESULTS: One thousand twenty two consecutive patients were referred for clinical coronary CTA with suspicion of ACS. Overall, median time to discharge home was 10.5 (5.7-24.1) hours. Patient disposition was 42.7 % direct discharge from the ED, 43.2 % discharge from emergency unit, and 14.1 % hospital admission. ACS rate during index hospitalization was 9.1 %. One hundred ninety two patients underwent additional diagnostic imaging and 77 underwent ICA. The positive predictive value of CTA compared to ICA was 78.9 % (95 %-CI 68.1-87.5 %). Median CT radiation exposure was 4.0 (2.5-5.8) mSv. No ACS was missed; MACE at follow-up after negative CTA was 0.2 %. CONCLUSIONS: Coronary CTA in an experienced tertiary care setting allows for efficient and safe management of patients with suspicion for ACS. KEY POINTS: • ED Coronary CTA using advanced systems is associated with low radiation exposure. • Negative coronary CTA is associated with low rates of MACE. • CTA in ED patients enables short median time to discharge home. • CTA strategy is characterized by few downstream tests including unnecessary ICA.

Dehiscence of a pulmonary bioprosthesis with a focal dissection of the pulmonary artery in a patient with congenital pulmonic stenosis.

Pulmonary valve replacement (PVR) is the most common adult congenital cardiac operation performed. Valve degeneration leading to prosthetic stenosis and/or regurgitation is a long-term risk in this population and may be associated with paravalvular leak (PVL). Complications involving the proximal pulmonary artery, including dissection, are less clearly defined. Herein, we report the case of a 30-year-old patient with a history of multiple pulmonary valve interventions secondary to congenital pulmonic stenosis, who developed dehiscence of a bioprosthetic PVR associated with significant paravalvular leak (PVL) and further complicated by a focal dissection of the proximal pulmonary artery.

Non-diagnostic coronary artery calcification and stenosis: a correlation of coronary computed tomography angiography and invasive coronary angiography.

Background Heavy coronary artery calcification (CAC) impairs diagnostic accuracy of coronary computed tomography angiography (cCTA) and is considered to be a major limitation. Purpose To investigate the effect of non-evaluable CAC seen on cCTA on clinical decision-making by determining the degree of subsequent invasive testing and to assess the relationship between non-evaluable segments containing CAC and significant stenosis as seen in invasive coronary angiography (ICA). Material and Methods The study comprised of 356 patients who underwent cCTA and subsequent ICA within 2 months between 2005 and 2009. Clinical reports were reviewed to identify the indications for referral to ICA. In a subset of 68 patients where non-diagnostic CAC on cCTA and significant stenosis on ICA were present in the same segment, we correlated and analyzed the underlying stenosis severity of the lesion on ICA to the cCTA. Lesions with CAC were analyzed in a standardized fashion by application of reading rules. Results Non-diagnostic CAC on cCTA prompted ICA in 5.6% of patients. CAC occurred at the site of maximum stenosis in segments with stenosis <50% (95.9% [47/49]), 50-69% (82.4% [28/34]), 70-99% (64.5% [31/48]), and 100% (33.3% [1/3]). At the point of maximum calcium deposit, non-obstructive disease was present in 61.2%. Application of reading rules resulted in a 44% reduction in non-diagnostic cCTA reads. Conclusion Severe CAC may prompt further investigation with ICA. There is less CAC with increasing lesion severity at the point of maximum stenosis. Additional application of reading rules improved non-diagnostic cCTA reads.

Gain-of-function mutations in SMAD4 cause a distinctive repertoire of cardiovascular phenotypes in patients with Myhre syndrome.

Myhre syndrome is a rare, distinctive syndrome due to specific gain-of-function mutations in SMAD4. The characteristic phenotype includes short stature, dysmorphic facial features, hearing loss, laryngotracheal anomalies, arthropathy, radiographic defects, intellectual disability, and a more recently appreciated spectrum of cardiovascular defects with a striking fibroproliferative response to surgical intervention. We report four newly described patients with typical features of Myhre syndrome who had (i) a mildly narrow descending aorta and restrictive cardiomyopathy; (ii) recurrent pericardial and pleural effusions; (iii) a large persistent ductus arteriosus with juxtaductal aortic coarctation; and (iv) restrictive pericardial disease requiring pericardiectomy. Additional information is provided about a fifth previously reported patient with fatal pericardial disease. A literature review of the cardiovascular features of Myhre syndrome was performed on 54 total patients, all with a SMAD4 mutation. Seventy percent had a cardiovascular abnormality including congenital heart defects (63%), pericardial disease (17%), restrictive cardiomyopathy (9%), and systemic hypertension (15%). Pericarditis and restrictive cardiomyopathy are associated with high mortality (three patients each among 10 deaths); one patient with restrictive cardiomyopathy also had epicarditis. Cardiomyopathy and pericardial abnormalities distinguish Myhre syndrome from other disorders caused by mutations in the TGF-ß signaling cascade (Marfan, Loeys-Dietz, or Shprintzen-Goldberg syndromes). We hypothesize that the expanded spectrum of cardiovascular abnormalities relates to the ability of the SMAD4 protein to integrate diverse signaling pathways, including canonical TGF-ß, BMP, and Activin signaling. The co-occurrence of congenital and acquired phenotypes demonstrates that the gene product of SMAD4 is required for both developmental and postnatal cardiovascular homeostasis. © 2016 Wiley Periodicals, Inc.

Medical Registry Data Collection Efficiency: A Crossover Study Comparing Web-Based Electronic Data Capture and a Standard Spreadsheet.

BACKGROUND: Electronic medical records and electronic data capture (EDC) have changed data collection in clinical and translational research. However, spreadsheet programs, such as Microsoft Excel, are still used as data repository to record and organize patient data for research. OBJECTIVE: The objective of this study is to assess the efficiency of EDC as against a standard spreadsheet in regards to time to collect data and data accuracy, measured in number of errors after adjudication. METHODS: This was a crossover study comparing the time to collect data in minutes between EDC and a spreadsheet. The EDC tool used was Research Electronic Data Capture (REDCap), whereas the spreadsheet was Microsoft Excel. The data collected was part of a registry of patients who underwent coronary computed tomography angiography in the emergency setting. Two data collectors with the same experience went over the same patients and collected relevant data on a case report form identical to the one used in our Emergency Department (ED) registry. Data collection tool was switched after the patient that represented half the cohort. For this, the patient cohort was exactly 30 days of our ED coronary Computed Tomography Angiography registry and the point of crossover was determined beforehand to be 15 days. We measured the number of patients admitted, and time to collect data. Accuracy was defined as absence of blank fields and errors, and was assessed by comparing data between data collectors and counting every time the data differed. Statistical analysis was made using paired t -test. RESULTS: The study included 61 patients (122 observations) and 55 variables. The crossover occurred after the 30th patient. Mean time to collect data using EDC in minutes was 6.2±2.3, whereas using Excel was 8.0±2.0 (P <.001), a difference of 1.8 minutes between both means (22%). The cohort was evenly distributed with 3 admissions in the first half of the crossover and 4 in the second half. We saw 2 (<0.1%) continuous variable typos in the spreadsheet that a single data collector made. There were no blank fields. The data collection tools showed no differences in accuracy of data on comparison. CONCLUSIONS: Data collection for our registry with an EDC tool was faster than using a spreadsheet, which in turn allowed more efficient follow-up of cases.

Cost-effectiveness of follow-up of pulmonary nodules incidentally detected on cardiac computed tomographic angiography in patients with suspected coronary artery disease.

BACKGROUND: Pulmonary nodules (PNs) are often detected incidentally during coronary computed tomographic (CT) angiography, which is increasingly being used to evaluate patients with chest pain symptoms. However, the efficiency of following up on incidentally detected PN is unknown. METHODS AND RESULTS: We determined demographic and clinical characteristics of stable symptomatic patients referred for coronary CT angiography in whom incidentally detected PNs warranted follow-up. A validated lung cancer simulation model was populated with data from these patients, and clinical and economic consequences of follow-up per Fleischner guidelines versus no follow-up were simulated. Of the 3665 patients referred for coronary CT angiography, 591 (16%) had PNs requiring follow-up. The mean age of patients with PNs was 59±10 years; 66% were male; 67% had ever smoked; and 21% had obstructive coronary artery disease. The projected overall lung cancer incidence was 5.8% in these patients, but the majority died of coronary artery disease (38%) and other causes (57%). Follow-up of PNs was associated with a 4.6% relative reduction in cumulative lung cancer mortality (absolute mortality: follow-up, 4.33% versus non-follow-up, 4.54%), more downstream testing (follow-up, 2.34 CTs per patient versus non-follow-up, 1.01 CTs per patient), and an average increase in quality-adjusted life of 7 days. Costs per quality-adjusted life-year gained were $154 700 to follow up the entire cohort and $129 800 per quality-adjusted life-year when only smokers were included. CONCLUSIONS: Follow-up of PNs incidentally detected in patients undergoing coronary CT angiography for chest pain evaluation is associated with a small reduction in lung cancer mortality. However, significant downstream testing contributes to limited efficiency, as demonstrated by a high cost per quality-adjusted life-year, especially in nonsmokers.