Coronary Artery Calcium in Assessment of Atherosclerotic Cardiovascular Disease Risk and its Role in Primary Prevention

Coronary artery calcium (CAC), which is detected using computed tomography scanning, is a well-established indicator of subclinical atherosclerosis. The CAC score is independently associated with atherosclerotic cardiovascular disease (ASCVD) outcomes and provides improved predictive values for estimating the risk of ASCVD beyond traditional risk factors. Thus, CAC is considered to have important implications for reclassification as a decision aid among individuals in the preclinical phase and as the primary prevention of ASCVD. This review is focused on epidemiological evidence on CAC in asymptomatic population-based samples from Western countries and Japan. We also discuss the usability of CAC as a tool for assessing ASCVD risk and its role in the primary prevention of ASCVD. A lack of evidence for the CAC score in ASCVD risk assessment beyond traditional risk factors in populations other than those in Western countries (including Japan) warrants further investigation. Clinical trials are also necessary to demonstrate the usefulness and safety of CAC screening in the primary prevention of ASCVD.

Evaluation of the Incremental Value of a Coronary Artery Calcium Score Beyond Traditional Cardiovascular Risk Assessment: A Systematic Review and Meta-analysis

IMPORTANCE

Coronary artery calcium scores (CACS) are used to help assess patients' cardiovascular status and risk. However, their best use in risk assessment beyond traditional cardiovascular factors in primary prevention is uncertain.

OBJECTIVE

To find, assess, and synthesize all cohort studies that assessed the incremental gain from the addition of a CACS to a standard cardiovascular disease (CVD) risk calculator (or CVD risk factors for a standard calculator), that is, comparing CVD risk score plus CACS with CVD risk score alone.

EVIDENCE REVIEW

Eligible studies needed to be cohort studies in primary prevention populations that used 1 of the CVD risk calculators recommended by national guidelines (Framingham Risk Score, QRISK, pooled cohort equation, NZ PREDICT, NORRISK, or SCORE) and assessed and reported incremental discrimination with CACS for estimating the risk of a future cardiovascular event.

FINDINGS

From 2772 records screened, 6 eligible cohort studies were identified (with 1043 CVD events in 17 961 unique participants) from the US (n = 3), the Netherlands (n = 1), Germany (n = 1), and South Korea (n = 1). Studies varied in size from 470 to 5185 participants (range of mean [SD] ages, 50 [10] to 75.1 [7.3] years; 38.4%-59.4% were women). The C statistic for the CVD risk models without CACS ranged from 0.693 (95% CI, 0.661-0.726) to 0.80. The pooled gain in C statistic from adding CACS was 0.036 (95% CI, 0.020-0.052). Among participants classified as being at low risk by the risk score and reclassified as at intermediate or high risk by CACS, 85.5% (65 of 76) to 96.4% (349 of 362) did not have a CVD event during follow-up (range, 5.1-10.0 years). Among participants classified as being at high risk by the risk score and reclassified as being at low risk by CACS, 91.4% (202 of 221) to 99.2% (502 of 506) did not have a CVD event during follow-up.

CONCLUSIONS AND RELEVANCE

This systematic review and meta-analysis found that the CACS appears to add some further discrimination to the traditional CVD risk assessment equations used in these studies, which appears to be relatively consistent across studies. However, the modest gain may often be outweighed by costs, rates of incidental findings, and radiation risks. Although the CACS may have a role for refining risk assessment in selected patients, which patients would benefit remains unclear. At present, no evidence suggests that adding CACS to traditional risk scores provides clinical benefit.

QUANTIFICATION OF PULMONARY PATHOLOGY IN CYSTIC FIBROSIS-COMPARISON BETWEEN DIGITAL CHEST TOMOSYNTHESIS AND COMPUTED TOMOGRAPHY

PURPOSE

Digital tomosynthesis (DTS) is currently undergoing validation for potential clinical implications. The aim of this study was to investigate the potential for DTS as a low-dose alternative to computed tomography (CT) in imaging of pulmonary pathology in patients with cystic fibrosis (CF).

METHODS

DTS and CT were performed as part of the routine triannual follow-up in 31 CF patients. Extent of disease was quantified according to modality-specific scoring systems. Statistical analysis included Spearman's rank correlation coefficient (r) and Krippendorff's alpha (α).

MAJOR FINDINGS

The median effective dose was 0.14 for DTS and 2.68 for CT. Intermodality correlation was very strong for total score and the subscores regarding bronchiectasis and bronchial wall-thickening (r = 0.82-0.91, P < 0.01). Interobserver reliability was high for total score, bronchiectasis and mucus plugging (α = 0.83-0.93) in DTS.

CONCLUSION

Chest tomosynthesis could be a low-dose alternative to CT in quantitative estimation of structural lung disease in CF.

The importance of low-dose CT screening to identify emphysema in asymptomatic participants with and without a prior diagnosis of COPD

PURPOSE

Chronic Obstructive Pulmonary Disease (COPD) includes chronic bronchitis, small airways disease, and emphysema. Diagnosis of COPD requires spirometric evidence and may be normal even when small airways disease or emphysema is present. Emphysema increases the risk of exacerbations, and is associated with all-cause mortality and increased risk of lung cancer. We evaluated the prevalence of emphysema in participants with and without a prior history of COPD.

METHODS

We reviewed a prospective cohort of 52,726 subjects who underwent baseline low dose CT screening for lung cancer from 2003 to 2016 in the International Early Lung Cancer Action Program.

RESULTS

Of 52,726 participants, 23.8%(12,542) had CT evidence of emphysema. Of these 12,542 participants with emphysema, 76.5%(9595/12,542) had no prior COPD diagnosis even though 23.6% (2258/9595) had moderate or severe emphysema. Among 12,542 participants, significant predictors of no prior COPD diagnosis were: male (OR = 1.47, p < 0.0001), younger age (OR_age10 = 0.72, p < 0.0001), lower pack-years of smoking (OR_10pack-years = 0.90, p < 0.0001), completed college or higher (OR = 1.54, p < 0.0001), no family history of lung cancer (OR = 1.12, p = 0.04), no self-reported cardiac disease (OR = 0.76, p = 0.0003) or hypertension (OR = 0.74, p < 0.0001). The severity of emphysema was significantly lower among the 9595 participants with no prior COPD diagnosis, the OR for moderate emphysema was OR_moderate = 0.58(p = 0.0007) and for severe emphysema, it was OR_severe = 0.23(p < 0.0001).

CONCLUSION

Emphysema was identified in 23.8% participants undergoing LDCT and was unsuspected in 76.5%. LDCT provides an opportunity to identify emphysema, and recommend smoking cessation.

Surveillance of small, solid pulmonary nodules at digital chest tomosynthesis: data from a cohort of the pilot Swedish CArdioPulmonary bioImage Study (SCAPIS)

Background

Digital tomosynthesis (DTS) might be a low-dose/low-cost alternative to computed tomography (CT).

Purpose

To investigate DTS relative to CT for surveillance of incidental, solid pulmonary nodules.

Material and Methods

Recruited from a population study, 106 participants with indeterminate solid pulmonary nodules on CT underwent surveillance with concurrently performed CT and DTS. Nodule size on DTS was assessed by manual diameter measurements and semi-automatic nodule segmentations were independently performed on CT. Measurement agreement was analyzed according to Bland–Altman with 95% limits of agreement (LoA). Detection of nodule volume change > 25% by DTS in comparison to CT was evaluated with receiver operating characteristics (ROC).

Results

A total of 81 nodules (76%) were assessed as measurable on DTS by two independent observers. Inter- and intra-observer LoA regarding change in average diameter were ± 2 mm. Calculation of relative volume change on DTS resulted in wide inter- and intra-observer LoA in the order of ± 100% and ± 50%. Comparing relative volume change between DTS and CT resulted in LoA of –58% to 67%. The area under the ROC curve regarding the ability of DTS to detect volumetric changes > 25% on CT was 0.58 (95% confidence interval [CI] = 0.40–0.76) and 0.50 (95% CI = 0.35–0.66) for the two observers.

Conclusion

The results of the present study show that measurement variability limits the agreement between DTS and CT regarding nodule size change for small solid nodules.

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

BACKGROUND

The effect of incidental findings from coronary computed tomography angiography (CCTA) on management has not been rigorously investigated. This study uses a control group to explore this relationship.

METHODS

Analysis of data from a randomized controlled trial of acute chest pain patients admitted to telemetry was performed. Patients were randomized to undergo either CCTA (n = 200) or radionuclide myocardial perfusion imaging (MPI) (n = 200). Incidental findings were determined from imaging reports. Records were reviewed to determine subsequent management and imaging during and after hospitalization. Comparisons were performed using Fischer's exact tests.

RESULTS

386 incidental findings were found among 187 CCTA studies. No extra-cardiac incidental findings were noted in the MPI arm, which served as an effective control group. There were significantly more non-coronary medical workups during admission in the CCTA group compared to the MPI group [20% (39) vs. 12% (23), P = 0.038]. CCTA patients underwent significantly more resting echocardiography during the inpatient workup compared to the MPI group [38% (75) vs. 18% (55), P = 0.042]. CCTA patients underwent significantly more non-contrast chest CT exams in the year following admission compared to MPI patients [14% (27) vs. 7% (13) P = 0.029].

CONCLUSIONS

Incidental findings on inpatient CCTAs performed for chest pain have a significant impact on treatment and imaging during and following hospital admission.

Incidental Findings on Coronary Computed Tomography Angiography in Human Immunodeficiency Virus (HIV)-Positive and HIV-Negative Persons

Background

Incidental findings on coronary computed tomography angiography (CCTA) have a great impact on the benefits and costs of testing for cardiovascular disease. The number of incidental findings might be increased in human immunodeficiency virus (HIV)-positive individuals compared with the general population. Data are limited regarding the association between incidental findings and HIV infection.

Methods

We assessed the prevalence and factors associated with incidental findings among HIV-positive and HIV-negative participants ≥45 years undergoing CCTA. Logistic regression was performed to evaluate the factors associated with incidental findings in the HIV-positive and HIV-negative groups. For the analysis of the HIV effect, a propensity score-matched dataset of HIV-positive/HIV-negative participants was used.

Results

We included 553 participants, 341 with and 212 without HIV infection. Incidental findings were observed in 291 of 553 (53%) patients. In 42 of 553 (7.6%) participants, an incidental finding resulted in additional workup. A malignancy was diagnosed in 2 persons. In the HIV-positive group, age (1.31 per 5 years, 1.10–1.56) and smoking (2.29, 1.43–3.70) were associated with incidental findings; in the HIV-negative group, age (1.26, 1.01–1.59) and a CAC score >0 (2.08, 1.09–4.02) were associated with incidental findings. Human immunodeficiency virus seropositivity did not affect the risk of incidental findings.

Conclusions

Incidental findings were highly prevalent among HIV-positive and HIV-negative persons. Human immunodeficiency virus infection was not associated with an increased risk of incidental findings.

Detection and Characterization of Solid Pulmonary Nodules at Digital Chest Tomosynthesis: Data from a Cohort of the Pilot Swedish Cardiopulmonary Bioimage Study

Purpose To investigate the performance of digital tomosynthesis (DTS) for detection and characterization of incidental solid lung nodules. Materials and Methods This prospective study was based on a population study with 1111 randomly selected participants (age range, 50-64 years) who underwent a medical evaluation that included chest computed tomography (CT). Among these, 125 participants with incidental nodules 5 mm or larger were included in this study, which added DTS in conjunction with the follow-up CT and was performed between March 2012 and October 2014. DTS images were assessed by four thoracic radiologists blinded to the true number of nodules in two separate sessions according to the 5-mm (125 participants) and 6-mm (55 participants) cut-off for follow-up of incidental nodules. Pulmonary nodules were directly marked on the images by the readers and graded regarding confidence of presence and recommendation for follow-up. Statistical analyses included jackknife free-response receiver operating characteristic, receiver operating characteristic, and Cohen κ coefficient. Results Overall detection rate ranges of CT-proven nodules 5 mm or larger and 6 mm or larger were, respectively, 49%-58% and 48%-62%. Jackknife free-response receiver operating characteristics figure of merit for detection of CT-proven nodules 5 mm or larger and 6 mm or larger was 0.47 and 0.51, respectively, and area under the receiver operating characteristic curve regarding recommendation for follow-up was 0.62 and 0.65, respectively. Conclusion Routine use of DTS would result in lower detection rates and reduced number of small nodules recommended for follow-up. ^© RSNA, 2018.

Incidental extra-cardiac findings on 13N-ammonia myocardial perfusion PET/CT

BACKGROUND

The objective of this study was to describe the prevalence of incidental extra-cardiac findings (IECFs) on myocardial perfusion PET/CTs and the prevalence of potentially clinically relevant and clinically irrelevant IECFs, as well as detection rate of previously unknown malignancies.

METHODS AND RESULTS

From September 2013 until February 2016, a total of 1397 consecutive patients referred for the evaluation of possible ischemia by 13NH3 PET/CT were prospectively included in a database. IECFs were categorized into three groups: potentially clinically relevant IECFs, IECFs that could potentially cause chest pain, and clinically irrelevant IECFs. Additionally, the prevalence of previously unknown malignancies was determined. In 717 (51%) of these patients, 775 IECFs were reported and 115 IECFs were categorized as potentially clinically relevant in 109 (8%) patients. A total of 145 IECFs that could potentially cause chest pain were detected in 139 (10%) patients and 515 clinically irrelevant IECFs were detected in 469 (34%) of the patients. An unknown primary malignancy was histologically proven in 19 patients (1.4%).

CONCLUSIONS

IECFs are detected on myocardial perfusion PET/CT in approximately half of the patients. In the present study, IECFs were potentially clinically relevant in 8% of the patients and in 1.4% an unknown malignancy was found, most of which were lung cancers.

Thoracic Malignancies and Pulmonary Nodules in Patients under Evaluation for Transcatheter Aortic Valve Implantation (TAVI): Incidence, Follow Up and Possible Impact on Treatment Decision

BACKGROUND

Transcatheter aortic valve implantation (TAVI) has become the treatment of choice in patients with severe aortic valve stenosis who are not eligible for operative replacement and an alternative for those with high surgical risk. Due to high age and smoking history in a high proportion of TAVI patients, suspicious findings are frequently observed in pre-procedural chest computer tomography (CCT).

METHODS

CCT scans of 484 consecutive patients undergoing TAVI were evaluated for incidentally discovered solitary pulmonary nodules (SPN).

RESULTS

In the entire study population, SPN ≥ 5 mm were found in 87 patients (18%). These patients were compared to 150 patients who were incidentally collected from the 397 patients without SPN or with SPN < 5 mm (control group). After a median follow-up of 455 days, lung cancer was diagnosed in only two patients. Neither SPN ≥ 5 mm (p = 0.579) nor SPN > 8 mm (p = 0.328) were significant predictors of overall survival.

CONCLUSIONS

Despite the high prevalence of SPNs in this single center TAVI cohort lung cancer incidence at midterm follow-up seems to be low. Thus, aggressive diagnostic approaches for incidentally discovered SPN during TAVI evaluation should not delay the treatment of aortic stenosis. Unless advanced thoracic malignancy is obvious, the well documented reduction of morbidity and mortality by TAVI outweighs potentially harmful delays regarding further diagnostics. Standard guideline-approved procedure for SPN can be safely performed after TAVI.

Per cent emphysema is associated with respiratory and lung cancer mortality in the general population: a cohort study

BACKGROUND

Emphysema on CT is a risk factor for all-cause mortality in persons with and without airflow obstruction; however, causes of death associated with emphysema remain uncertain, particularly in the general population.

AIMS

To test associations between quantitatively assessed emphysema on CT and cause of death in persons with and without a substantial smoking history.

METHODS

The Multi-Ethnic Study of Atherosclerosis recruited 6814 participants, aged 45-84 years and without clinical cardiovascular disease, in 2000-2002. Per cent emphysema was defined on cardiac CT as per cent of lung voxels less than -950 Hounsfield units; emphysema on CT was defined as per cent emphysema above the upper limit of normal. Cause of death was classified by administrative codes. Proportional-hazards models were adjusted for age, race/ethnicity, gender, body mass index, smoking status, pack-years, coronary artery calcium, site and education. Additional adjustment for lung function was made in a subset with spirometry from 2004 to 2006.

RESULTS

There were 1091 deaths over 12 years median follow-up. Emphysema on CT was strongly associated with increased mortality due to respiratory diseases (adjusted HR 2.94, 95% CI 1.68 to 5.15), particularly chronic lower respiratory diseases (adjusted HR 9.54, 95% CI 4.70 to 19.35), and lung cancer (adjusted HR 1.84, 95% CI 1.09 to 3.12), but not cardiovascular disease. Associations persisted among participants with fewer than 10 pack-years and those without physician-diagnosed respiratory disease, and were similar after adjustment for airflow measures and in persons without airflow limitation.

CONCLUSIONS

Quantitatively assessed emphysema on CT is associated with greater respiratory disease and lung cancer mortality, even among persons without traditional risk factors.

No Value for Routine Chest Radiography in the Work-Up of Early Stage Cervical Cancer Patients

Aim

Evidence supporting the recommendation to include chest radiography in the work-up of all cervical cancer patients is limited. We investigated the diagnostic value of routine chest radiography in cervical cancer staging.

Methods

All consecutive cervical cancer patients who presented at our tertiary referral center in the Netherlands (January 2006 – September 2013), and for whom ≥6 months follow-up was available, were included. As part of the staging procedure, patients underwent a routine two-directional digital chest radiograph. Findings were compared to a composite reference standard consisting of all imaging studies and histology obtained during the 6 months following radiography.

Results

Of the 402 women who presented with cervical cancer, 288 (71.6%) underwent chest radiography and had ≥6 months follow-up. Early clinical stage (I/II) cervical cancer was present in 244/288 (84.7%) women, while 44 (15.3%) presented with advanced disease (stage III/IV). The chest radiograph of 1 woman – with advanced pre-radiograph stage (IVA) disease – showed findings consistent with pulmonary metastases. Radiographs of 7 other women – 4 early, 3 advanced stage disease – were suspicious for pulmonary metastases which was confirmed by additional imaging in only 1 woman (with pre-radiograph advanced stage (IIIB) disease) and excluded in 6 cases, including all women with early stage disease. In none of the 288 women were thoracic skeletal metastases identified on imaging or during 6 months follow up. Radiography was unremarkable in 76.4% of the study population, and showed findings unrelated to the cervical carcinoma in 21.2%.

Conclusion

Routine chest radiography was of no value for any of the early stage cervical cancer patients presenting at our tertiary center over a period of 7.7 years.

Clinical and economic consequences of non-cardiac incidental findings detected on cardiovascular computed tomography performed prior to transcatheter aortic valve implantation (TAVI)

Transcatheter aortic valve implantation (TAVI) is an effective treatment option for patients with severe degenerative aortic valve stenosis who are high risk for conventional surgery. Computed tomography (CT) performed prior to TAVI can detect pathologies that could influence outcomes following the procedure, however the incidence, cost, and clinical impact of incidental findings has not previously been investigated. 279 patients underwent CT; 188 subsequently had TAVI and 91 were declined. Incidental findings were classified as clinically significant (requiring treatment), indeterminate (requiring further assessment), or clinically insignificant. The primary outcome measure was all-cause mortality up to 3 years. Costs incurred by additional investigations resultant to incidental findings were estimated using the UK Department of Health Payment Tariff. Incidental findings were common in both the TAVI and medical therapy cohorts (54.8 vs. 70.3%; P = 0.014). Subsequently, 45 extra investigations were recommended for the TAVI cohort, at an overall average cost of £32.69 per TAVI patient. In a univariate model, survival was significantly associated with the presence of a clinically significant or indeterminate finding (HR 1.61; P = 0.021). However, on multivariate analysis outcomes after TAVI were not influenced by any category of incidental finding. Incidental findings are common on CT scans performed prior to TAVI. However, the total cost involved in investigating these findings is low, and incidental findings do not independently identify patients with poorer outcomes after TAVI. The discovery of an incidental finding on CT should not necessarily influence or delay the decision to perform TAVI.

Evaluation of accuracy and precision of manual size measurements in chest tomosynthesis using simulated pulmonary nodules

RATIONALE AND OBJECTIVES

To investigate the accuracy and precision of pulmonary nodule size measurements on chest tomosynthesis images.

MATERIALS AND METHODS

Artificial ellipsoid-shaped nodules with known sizes were inserted in clinical chest tomosynthesis images. The volume of the nodules corresponded to that of a sphere with a diameter of 4.0, 8.0, or 12.0 mm. Four thoracic radiologists were given the task to determine the longest diameter of the nodules. All nodules were measured twice. Measurement accuracy in terms of the mean measurement error was determined. Intraobserver and interobserver variabilities, as well as variability because of differences between nodules and their locations, were used as measures of precision.

RESULTS

The mean measurement error ranged from -0.3 to 0.1 mm for the nodule size groups and observers. Of the smallest nodules, the observers found 7-17 of total 50 nodules nonmeasurable. The intraobserver and interobserver variabilities were of similar magnitude, indicating relatively small differences between the observers. The internodule variability was in general larger, indicating that the different characteristics of the nodules and their location are sources of variability.

CONCLUSIONS

The results suggest a high accuracy and precision for manual measurements of the nodules in chest tomosynthesis images. However, small nodules (<5.0 mm) may be difficult to measure at all because of poor visibility.

Two-year survival of patients screened for transcatheter aortic valve replacement with potentially malignant incidental findings in initial body computed tomography

Aims

Recently, transcatheter aortic valve replacement (TAVR) has evolved as the standard treatment in patients with inoperable aortic valve stenosis. According to TAVR guidelines, body computed tomography (CT) is recommended for pre-procedural planning. Due to the advanced age of these patients, multiple radiological potentially malignant incidental findings (pmIFs) appear in this cohort. It is unknown how pmIFs influence the decision by the heart team to intervene and the mortality.

Methods and results

We evaluated in a retrospective single-centre observational study 414 participants screened for TAVR with dual-source CT between October 2010 and December 2012. pmIFs are common and appeared in 18.7% of all patients screened for TAVR. The decision to intervene by TAVR or surgical aortic valve replacement (SAVR) was made by an interdisciplinary heart team and the role of pmIF in decision-making and time to treatment with TAVR or SAVR was analysed, retrospectively. The appearance of a pmIF vs. no pmIF did not significantly influence therapeutic decisions [odds ratio (OR) 1.14; P = 0.835] or time to treatment (91 ± 152 vs. 61 ± 109 days, respectively). Several findings, which are highly suspicious for malignancy, were less likely associated with invasive treatment (OR 0.207; P = 0.046). Patient survival was evaluated for at least 2 years until January 2014. Two-year survival of patients after TAVR or SAVR, treated according to the heart team decision, was ∼75% and independent from the presence of a non-severe (P = 0.923) or severe (P = 0.823) pmIF.

Conclusion

The study indicates that frequently occurring radiologic pmIF did not influence 2-year survival after a decision to intervene was made by an interdisciplinary heart team.

Association between emphysema-like lung on cardiac computed tomography and mortality in persons without airflow obstruction: a cohort study

BACKGROUND

Low lung function is known to predict mortality in the general population, but the prognostic significance of emphysema on computed tomography (CT) in persons without chronic obstructive pulmonary disease (COPD) is uncertain.

OBJECTIVE

To determine whether greater emphysema-like lung on CT is associated with all-cause mortality among persons in the general population without airflow obstruction or COPD.

DESIGN

Prospective cohort study.

SETTING

Population-based, multiethnic sample from 6 U.S. communities.

PARTICIPANTS

2965 participants aged 45 to 84 years without airflow obstruction on spirometry.

MEASUREMENTS

Emphysema-like lung was defined as the number of lung voxels with attenuation less than -950 Hounsfield units on cardiac CT and was adjusted for the number of total imaged lung voxels.

RESULTS

Among 2965 participants, 50.9% of whom had never smoked, there were 186 deaths over a median of 6.2 years. Greater emphysema-like lung was independently associated with increased mortality (adjusted hazard ratio per one-half interquartile range, 1.14 [95% CI, 1.04 to 1.24]; P=0.004) after adjustment for potential confounders, including cardiovascular risk factors and FEV1. Generalized additive models supported a linear association between emphysema-like lung and mortality without evidence for a threshold. The association was of greatest magnitude among smokers, although multiplicative interaction terms did not support effect modification by smoking status.

LIMITATIONS

Cardiac CT scans did not include lung apices. The number of deaths was limited among subgroup analyses.

CONCLUSION

Emphysema-like lung on CT was associated with all-cause mortality among persons without airflow obstruction or COPD in a general population sample, particularly among smokers. Recognition of the independent prognostic significance of emphysema on CT among patients without COPD on spirometry is warranted.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute.

Accuracy of clinicians and models for estimating the probability that a pulmonary nodule is malignant

RATIONALE

Management of pulmonary nodules depends critically on the probability of malignancy. Models to estimate probability have been developed and validated, but most clinicians rely on judgment.

OBJECTIVES

The aim of this study was to compare the accuracy of clinical judgment with that of two prediction models.

METHODS

Physician participants reviewed up to five clinical vignettes, selected at random from a larger pool of 35 vignettes, all based on actual patients with lung nodules of known final diagnosis. Vignettes included clinical information and a representative slice from computed tomography. Clinicians estimated the probability of malignancy for each vignette. To examine agreement with models, we calculated intraclass correlation coefficients (ICC) and kappa statistics. To examine accuracy, we compared areas under the receiver operator characteristic curve (AUC).

MEASUREMENTS AND MAIN RESULTS

Thirty-six participants completed 179 vignettes, 47% of which described patients with malignant nodules. Agreement between participants and models was fair for the Mayo Clinic model (ICC, 0.37; 95% confidence interval [CI], 0.23-0.50) and moderate for the Veterans Affairs model (ICC, 0.46; 95% CI, 0.34-0.57). There was no difference in accuracy between participants (AUC, 0.70; 95% CI, 0.62-0.77) and the Mayo Clinic model (AUC, 0.71; 95% CI, 0.62-0.80; P = 0.90) or the Veterans Affairs model (AUC, 0.72; 95% CI, 0.64-0.80; P = 0.54).

CONCLUSIONS

In this vignette-based study, clinical judgment and models appeared to have similar accuracy for lung nodule characterization, but agreement between judgment and the models was modest, suggesting that qualitative and quantitative approaches may provide complementary information.

Malignant incidental extracardiac findings on cardiac CT: systematic review and meta-analysis

OBJECTIVE

The objective of our study was to systematically review the evidence on incidental extracardiac findings on cardiac CT with a focus on previously unknown malignancies.

MATERIALS AND METHODS

A systematic search was performed (PubMed, EMBASE, Cochrane databases) for studies reporting incidental extracardiac findings on cardiac CT. Among 1099 articles initially found, 15 studies met the inclusion criteria. The references of those articles were hand-searched and 14 additional studies were identified. After review of the full text, 10 articles were excluded. Nineteen studies including 15,877 patients (64% male) were analyzed. A three-level analysis was performed to determine the prevalence of patients with incidental extracardiac findings, the prevalence of patients with major incidental extracardiac findings, and the prevalence of patients with a proven cancer. Heterogeneity was explored for multiple variables. Pooled prevalence and 95% CI were calculated.

RESULTS

The prevalence of both incidental extracardiac findings and major incidental extracardiac findings showed a high heterogeneity (I2>95%): The pooled prevalence was 44% (95% CI, 35-54%) and 16% (95% CI, 14-20%), respectively. No significant explanatory variables were found for using or not using contrast material, the size of the FOV, and study design (I2>85%). The pooled cancer prevalence for 10 studies including 5082 patients was 0.7% (95% CI, 0.5-1.0%), with an almost perfect homogeneity (I2<0.1%). Of 29 reported malignancies, 21 (72%) were lung cancers; three, thyroid cancers; two, breast cancers; two, liver cancers; and one, mediastinal lymphoma.

CONCLUSION

Although the prevalence of reported incidental extracardiac finding at cardiac CT was highly variable, a homogeneous prevalence of previously unknown malignancies was reported across the studies, for a pooled estimate of 0.7%; more than 70% of these previously unknown malignancies were lung cancers. Extracardiac findings on cardiac CT require careful evaluation and reporting.

Incidentalology: A developing urological sub-specialty

OBJECTIVE

To identify the incidence and features of significant incidental findings discussed at our departmental multidisciplinary team meeting (MDM). The improved quality of radiological imaging has resulted in increased rates of incidental findings. Although some may be trivial, many have clinical significance and early diagnosis and treatment may be beneficial.

METHODS

A retrospective analysis was performed of all cases discussed at the MDM between January 2012 and February 2013. Cases were divided into two groups--Group 1 consisted of patients whose initial imaging was performed for a urological presentation which resulted in a synchronous finding; Group 2 consisted of patients who were referred with a synchronous urological finding for discussion following investigation of an initial benign urological condition or a non-urological condition.

RESULTS

696 patients were discussed at 53 MDMs. 109 (15.7%) patients had incidental findings. 61 (56%) of these were in Group 1. 16 (26.2%) were synchronous malignant diagnoses, 25 (41%) were benign and 20 (32.8%) were indeterminate. 48 (44%) patients in Group 2 - 40 (83.3%) were renal in origin and 30 (75%) of these proceeded to surgery. The median tumour size was 3.2 cm (Range: 1.2 cm-10 cm). One patient had radio-frequency ablation. Two were referred for palliative care. Seven patients are under ongoing surveillance--the median size of these lesions is 3.6 cm (Range: 2.1 cm-8.3 cm).

CONCLUSION

A substantial workload is generated from the investigation of incidental findings discussed at MDM--these now represent the majority of the caseload for renal cancer surgery.

Unrequested findings on cardiac computed tomography: looking beyond the heart

Objectives

To determine the prevalence of clinically relevant unrequested extra-cardiac imaging findings on cardiac Computed Tomography (CT) and explanatory factors thereof.

Methods

A systematic review of studies drawn from online electronic databases followed by meta-analysis with meta-regression was performed. The prevalence of clinically relevant unrequested findings and potentially explanatory variables were extracted (proportion of smokers, mean age of patients, use of full FOV, proportion of men, years since publication).

Results

Nineteen radiological studies comprising 12922 patients met the inclusion criteria. The pooled prevalence of clinically relevant unrequested findings was 13% (95% confidence interval 9–18, range: 3–39%). The large differences in prevalence observed were not explained by the predefined (potentially explanatory) variables.

Conclusions

Clinically relevant extra-cardiac findings are common in patients undergoing routine cardiac CT, and their prevalence differs substantially between studies. These differences may be due to unreported factors such as different definitions of clinical relevance and differences between populations. We present suggestions for basic reporting which may improve the interpretability and comparability of future research.

A meta-analysis and systematic review of computed tomography angiography as a diagnostic triage tool for patients with chest pain presenting to the emergency department

BACKGROUND

To assess clinical utility of computed tomography angiography (CTA) in the diagnosis of chest pain patients presenting to emergency departments (EDs), we conducted a meta-analysis of CTA in patients with suspected acute coronary syndromes (ACSs).

METHODS

386 studies were identified on initial review of literature. Inclusion criteria were: (1) prospective study with ≥1 month follow-up, (2) use of CTA in the ED setting, (3) use of ACC/AHA definitions for ACS and robust assessment of major adverse cardiac events, (4) ≥30 patients, and (5) study population with initial non-diagnostic ECGs and negative biomarkers.

RESULTS

Nine studies (N = 1349) formed the data set. The pooled patient population was 52 ± 2 years of age, 51% male, with low to intermediate pretest probability for ACS. Risk factors included 12% diabetes, 42% hypertension, 35% smokers, 29% had hyperlipidemia, and 7% known CAD. ACS was subsequently diagnosed in 10% of patients. The bivariate summary estimate of sensitivity of CTA for ACS diagnosis was 95% (95% CI 88-100) and specificity was 87% (95% CI 83-92), yielding a negative likelihood ratio of 0.06 (95% CI 0-0.14) and positive likelihood ratio of 7.4 (95% CI 4.8-10). The 30-day event rate included no deaths and no additional MIs.

CONCLUSION

Coronary CTA demonstrates a high sensitivity and a low negative likelihood ratio of 0.06, and is effective in ruling out the presence of ACS in low to intermediate risk patients presenting to the ED with acute chest pain.

Clinically significant incidental findings among human immunodeficiency virus-infected men during computed tomography for determination of coronary artery calcium

Those infected with the human immunodeficiency virus (HIV) have a greater risk of cardiovascular disease and might undergo computed tomographic (CT) scans for early detection. Incidental findings on cardiac CT imaging are important components of the benefits and costs of testing. We determined the prevalence and factors associated with incidental findings on CT scans performed to screen for coronary artery calcium (CAC) among HIV-infected men. A clinically significant finding was defined as requiring additional workup or a medical referral. A total of 215 HIV-infected men were evaluated. Their median age was 43 years; 17% were current tobacco users; the median CD4 count was 580 cells/mm(3); and 83% were receiving antiretroviral medications. Also, 34% had a positive CAC score of >0. An incidental finding was noted among 93 participants (43%), with 36 (17%) having ≥1 clinically significant finding. A total of 139 findings were noted, most commonly pulmonary nodules, followed by granulomas, scarring, and hilar adenopathy. Most of the incidental findings were stable on follow-up, and no malignancies were detected. The factors associated with the presence of an incidental finding in the multivariate model included increasing age (odds ratio 1.6 per 10 years, p <0.01), positive CAC score (odds ratio 2.3, p <0.01), and current tobacco use (odds ratio 2.5, p = 0.02). In conclusion, incidental findings were common among HIV-infected men undergoing screening CT imaging for CAC determination. The incidental findings were more common among older patients and those with detectable CAC.

Incidental findings in imaging research: evaluating incidence, benefit, and burden

BACKGROUND

Little information exists concerning the frequency and medical significance of incidental findings (IFs) in imaging research.

METHODS

Medical records of research participants undergoing a research imaging examination interpreted by a radiologist during January through March 2004 were reviewed, with 3-year clinical follow-up. An expert panel reviewed all IFs generating clinical action to determine medical benefit/burden on the basis of predefined criteria. The frequency of IFs that generated further clinical action was estimated by modality, body part, age, and sex, along with net medical benefit or burden.

RESULTS

Of 1426 research imaging examinations, 567 (39.8%) had at least 1 IF (1055 total). Risk of an IF increased significantly by age (odds ratio [OR], 1.5; 95% confidence interval, 1.4-1.7 per decade increase). Abdominopelvic computed tomography generated more IFs than other examinations (OR, 18.9 vs ultrasonography; 9.2% with subsequent clinical action), with computed tomography of the thorax and magnetic resonance imaging of the head next (OR, 11.9 and 5.9; 2.8% and 2.2% with action, respectively). Of the 567 examinations with an IF, 35 (6.2%) generated clinical action, resulting in clear medical benefit in 1.1% (6 of 567) and clear medical burden in 0.5% (3 of 567). Medical benefit/burden was usually unclear (26 of 567 [4.6%]).

CONCLUSIONS

Frequency of IFs in imaging research examinations varies significantly by imaging modality, body region, and age. Research imaging studies at high risk for generating IFs can be identified. Routine evaluation of research images by radiologists may result in identification of IFs in a high number of cases and subsequent clinical action to address them in a small but significant minority. Such clinical action can result in medical benefit to a small number of patients.

Incidental extracardiac findings at coronary CT: clinical and economic impact

OBJECTIVE

The purpose of this study was to evaluate the prevalence of incidental extracardiac findings on coronary CT, to determine the associated downstream resource utilization, and to estimate additional costs per patient related to the associated diagnostic workup.

MATERIALS AND METHODS

This retrospective study examined incidental extracardiac findings in 151 consecutive adults (69.5% men and 30.5% women; mean age, 54 years) undergoing coronary CT during a 7-year period. Incidental findings were recorded, and medical records were reviewed for downstream diagnostic examinations for a follow-up period of 1 year (minimum) to 7 years (maximum). Costs of further workup were estimated using 2009 Medicare average reimbursement figures.

RESULTS

There were 102 incidental extracardiac findings in 43% (65/151) of patients. Fifty-two percent (53/102) of findings were potentially clinically significant, and 81% (43/53) of these findings were newly discovered. The radiology reports made specific follow-up recommendations for 36% (19/53) of new significant findings. Only 4% (6/151) of patients actually underwent follow-up imaging or intervention for incidental findings. One patient was found to have a malignancy that was subsequently treated. The average direct costs of additional diagnostic workup were $17.42 per patient screened (95% CI, $2.84-$32.00) and $438.39 per patient with imaging follow-up (95% CI, $301.47-$575.31).

CONCLUSION

Coronary CT frequently reveals potentially significant incidental extracardiac abnormalities, yet radiologists recommend further evaluation in only one-third of cases. An even smaller fraction of cases receive further workup. The failure to follow-up abnormal incidental findings may result in missed opportunities to detect early disease, but also limits the short-term attributable costs.

Lung cancer detected at cardiac CT: prevalence, clinicoradiologic features, and importance of full-field-of-view images

PURPOSE

To retrospectively evaluate the prevalence and clinicoradiologic features of lung cancer detected at cardiac computed tomography (CT) and compare the detection rates at different field-of-view (FOV) settings.

MATERIALS AND METHODS

The institutional review board approved this retrospective study and waived the requirement for patient consent. Patients with lung cancer initially detected at cardiac CT were identified by means of a retrospective search of a lung cancer registry patient database between January 2004 and December 2007. Patients known to have lung cancer at the time of cardiac CT were excluded. The prevalence and clinical and radiologic features of lung cancer were evaluated. The rates of lung cancer detection at three FOVs-limited and full FOV at cardiac scanning and full FOV at thoracic scanning-were compared by using McNemar testing.

RESULTS

The prevalence of lung cancer detected at CT was 0.31% (36 of 11654 patients, 16 [44%] never smokers) and was higher in patients suspected or known to have coronary artery disease (0.43% [24 of 5615 patients]) than in asymptomatic screening-examined patients (0.20% [12 of 5924 patients]) (P = .0457). Adenocarcinoma was the most common (in 31 [86%] of 36 patients) histologic subtype. Of 34 non-small cell lung cancers, 23 (68%)-including 16 stage IA cancers-were resectable. Four (11%) and 19 (53%) of the 36 CT-depicted cancers were visible in limited and full FOV at cardiac scanning, respectively, and 17 (47%) were visible in full FOV at thoracic scanning only.

CONCLUSION

The prevalence of lung cancer at cardiac CT was 0.31%; and 68% of these malignancies were at a resectable stage. Use of a limited FOV at cardiac scanning led to a large majority (89% [32 of 36 cancers]) of the lung cancers detected at full thoracic scanning being missed; thus, inclusion of the entire chest at cardiac CT is advisable.

Potential clinical and economic consequences of noncardiac incidental findings on cardiac computed tomography

OBJECTIVES

We sought to determine the incidence, clinical significance, and potential financial impact of noncardiac incidental findings (IF) identified with cardiac computed tomography (CT).

BACKGROUND

Cardiac CT is gaining acceptance and may lead to the frequent discovery of extracardiac IF.

METHODS

Consecutive patients undergoing cardiac CT had noncardiac structures evaluated after full field of view (32 to 50 cm) reconstruction. IF were categorized as clinically significant (CS), indeterminate, or clinically insignificant. Patient follow-up was performed by telephone, and verified with hospital records and/or communication with physicians.

RESULTS

Of 966 patients (58 +/- 16 years of age, 55.4% men, >98% outpatients), 401 (41.5%) patients had noncardiac IF. A total of 12 (1.2%) patients had CS findings, and 68 (7.0%) patients had indeterminate findings. At follow-up (18.4 +/- 7.6 months), none of the indeterminate findings became CS. Although 3 patients with indeterminate findings were diagnosed with malignant lesions, they were unrelated to the IF. After adjusting for age, IF were not an independent predictor of noncardiac death. Noncardiac death and cancer death in patients with and without IF were not statistically different. One patient suffered a major complication related to the investigation of an IF. The total direct cost associated with investigating IF was Canadian $57,596 (U.S. $83,035).

CONCLUSIONS

Although noncardiac IF are common, clinically significant or indeterminate IF are less prevalent. Rates of death were similar in patients with and without IF, and IF was not an independent predictor of noncardiac death. The investigation of IF is not without cost or risk. Larger studies are required to assess the potential mortality benefit of identifying IF.

Incidentally detected small pulmonary nodules on CT

The widespread use of multidetector computed tomography for imaging of the chest has lead to a significant increase in the number of incidentally detected pulmonary nodules. The significance of these nodules is often uncertain and further investigations may be required. This article will review the spectrum of imaging appearances of small pulmonary nodules, and highlight the few features that allow confident characterization of a nodule as benign or malignant; current guidelines for the management of incidentally detected nodules will also be discussed.

Significance of cardiac computed tomography incidental findings in acute chest pain

BACKGROUND

Coronary computed tomography angiography might improve the management of patients presenting to the emergency department with acute chest pain; however, noncoronary incidental findings are frequently detected. The prevalence and clinical significance of these findings have not been well described.

METHODS

Consecutive patients presenting to the emergency department with acute chest pain and inconclusive initial evaluation between May 2005 and May 2007 underwent 64-slice coronary computed tomography angiography before hospital admission with noncoronary incidental findings immediately reported. An expert panel adjudicated which incidental findings changed in-hospital patient management, and projections for additional testing were based on standard medical practice.

RESULTS

Among 395 patients (37.0% were female, mean age 53 +/- 12 years), incidental findings were detected in 44.8% (n = 177): noncalcified pulmonary nodules (n = 94, 23.8%), simple liver cysts (n = 26, 6.6%), calcified pulmonary nodules (n = 16, 4.1%), and contrast-enhancing liver lesions (n = 9, 2.3%). In-hospital management was changed because of incidental finding reporting in 5 patients (1.3%), and a potential alternative diagnosis was offered in another 16 patients (4.1%). Subsequent diagnostic imaging tests were recommended in 81 patients (20.5%), including 74 chest computed tomography scans. After 6 months, biopsy was performed in 3 patients, revealing cancer in 2 (0.5%) who underwent successful tumor resection.

CONCLUSION

Clinically important findings are detected in up to 5% of patients with a lead symptom of acute chest pain and low to intermediate likelihood of acute coronary syndrome, but only few directly change patient management; 21% are recommended for further imaging tests, resulting in invasive procedures and detection of cancer in few patients.

Clinical relevance and scope of accidental extracoronary findings in coronary computed tomography angiography: a cardiac versus thoracic FOV study

OBJECTIVE

To assess the spectrum and clinical relevance of extracoronary findings in coronary CT angiography (CCTA), and to compare a small (cardiac) field of view (FOV) to a large (thoracic) FOV setting.

MATERIAL AND METHODS

1084 consecutive patients (mean 57 years) with low-to-intermediate risk of coronary artery disease were enrolled. 542 CCTA scans were interpreted with small FOV (160-190mm(2)) encompassing the cardiac region. In another 542 CCTA (patients matched for age and gender), read-out of an additional full FOV (>320mm(2)) covering the thorax was performed. Clinical relevance of extracoronary findings was considered as either "significant" or "non-significant". "Significant" findings were subclassified as either score 1: findings necessitating immediate therapeutic actions, or score 2: findings with undoubted clinical or prognostic relevance, requiring clinical awareness, follow-up or further investigations (non-urgent). "Non-significant" findings were assigned to either score 3: findings not requiring follow-up or further tests, or as score 4: irrelevant incidental findings.

RESULTS

Significantly more patients with extracoronary findings were identified by using a full FOV with 43.2% (234/542) compared to a small FOV with 33.6% (182/542) (p=0.001). Similarly, a higher total number of extracoronary findings (n=394) was found on full FOV compared to small FOV (n=250) (p<0.001). The detection rate of clinically significant findings was higher by using full FOV compared to small FOV (25.6% versus 15.4%) (p<0.001), out of those 2.2% versus 1.8% of findings required immediate actions (score 1), and 23.4% versus 13.6% (p=0.0001), respectively were of clinical relevance (non-urgent, score 2). The rate of malign findings was 0.2%, and of acute pulmonary embolism 0.1%. More lung pathologies were observed by using full FOV compared to small FOV (22% versus 7%) (p<0.0001), and the detection rate of intrapulmonary nodules increased by 2.1%. Prevalence of aortic valve calcification (n=72) was 13.3%, out of those 7% had less than 2cm(2) aortic valve orifice area.

CONCLUSIONS

The interpretation of extracoronary findings on CCTA scans is mandatory given high prevalence of clinically significant findings by using a full "thoracic" FOV.

Unexpected findings at imaging: predicting frequency in various types of studies

OBJECTIVE

: The objective was to evaluate the prevalence and associated variables of unsuspected findings from imaging tests in clinical practice.

MATERIAL AND METHODS

: Cross-sectional study of patients referred for an imaging test in 2006. Two independent radiologists classified the imaging tests according to the presence or absence of an unexpected finding in relation with the causes that prompted the test (kappa=0.95). A thorough chart review of these patients was carried out as a quality control.

RESULTS

: Out of 3259 patients in the study, 488 revealed unsuspected findings (15.0%). The prevalence of abnormal findings varied according to age: from 20.4% (150/734) in the over 74-group to 9.0% (76/847) in the under 43-group. The largest prevalence was in the category of infectious diseases (14/49, 28.6%) and in CT (260/901, 28.9%) and ultrasound (138/668, 20.7%). Studies showing moderate clinical information on the referral form were less likely to show unexpected findings than those with null or minor information (OR 0.51; 95% CI 0.36-0.73).

CONCLUSION

: Clinicians should expect the frequency of diseases detectable by imaging to increase in the future. Further research with follow-up of these findings is needed to estimate the effect of imaging technologies on final health outcomes.

Incidental extracardiac findings at cardiac CT angiography: comparison of prevalence and clinical significance between precontrast low-dose whole thoracic scan and postcontrast retrospective ECG-gated cardiac scan

PURPOSE

To compare the prevalence and clinical significance of incidental extracardiac findings at cardiac CT angiography (CCTA) with precontrast low-dose whole thoracic scan (LDCT) and ECG-gated CCTA.

MATERIALS AND METHODS

We reviewed 254 patients who underwent CCTA. All participants first underwent LDCT to determine a range for CCTA and to screen unrecognized extracardiac lesions. CCTA was reconstructed with a small field of view of the heart. Clinically significant extracardiac findings were defined as abnormalities requiring further diagnostic work up, therapeutic intervention, or follow-up.

RESULTS

On LDCT, 285 extracardiac findings were detected in 62.6% patients; on CCTA, 18 findings in 7% patients. Among these, 66 findings in 20.4% patients were considered clinically significant on LDCT, and 4 findings in 1.6% patients on CCTA.

CONCLUSION

Clinically significant extracardiac findings are common in patients undergoing CCTA with a considerable number of extracardiac findings being detected only on LDCT. We advise performing whole thorax LDCT prior to CCTA.

Incidental pulmonary nodules on cardiac computed tomography: prognosis and use

BACKGROUND

Small asymptomatic lung nodules are found frequently in the course of cardiac computed tomography (CT) scanning. However, the utility of assessing and reporting incidental findings in healthy, asymptomatic subjects is unknown.

METHODS

The sample comprised 1023 60- to 69-year-old subjects free of clinical cardiovascular disease and cancer who participated in the Atherosclerotic Disease, VAscular functioN and genetiC Epidemiology Study. All subjects underwent cardiac CT for determination of coronary calcium between 2001 and 2004, and the first 459 subjects were assessed for incidental pulmonary findings. We used health plan clinical databases to ascertain 24-month health care use and clinical outcomes.

RESULTS

Noncalcified pulmonary nodules were reported in 81 of 459 subjects (18%). Chest CT was performed on 78% of participants in the 24 months after notification, compared with 2.5% in the previous 24 months. Chest x-ray use increased from 28% to 49%. The mean number of chest CT scans per subject was 1.3 (range, 0-5). Although no malignant lesions were diagnosed in the group who had pulmonary findings read, 1 lung cancer case was diagnosed in the group who did not have lung findings read. Among the 63 participants followed up by CT, the original lesion was not identified in 22 participants (35%), the lesion had decreased or remained stable in 39 participants (62%), and there was interval growth in 2 participants (3%).

CONCLUSION

Reporting noncalcified pulmonary nodules resulted in substantial rescanning that overwhelmingly revealed resolution or stability of pulmonary nodules, arguing for benign processes.