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1.  Cost-Effectiveness of Follow-Up of Pulmonary Nodules Incidentally Detected on Cardiac CT Angiography in Patients with Suspected Coronary Artery Disease 
Circulation  2014;130(8):668-675.
Pulmonary nodules (PN) are often incidentally detected during coronary CT angiography (CCTA) which is increasingly 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 CCTA in whom incidentally detected PN 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 3,665 patients referred to CCTA, 591 (16%) had PN requiring follow-up. Mean age of patients with PN was 59±10 years, 66% were male, 67% had ever smoked, and 21% had obstructive CAD. The projected overall lung cancer incidence was 5.8% in these patients, but the majority died from CAD (38%) and other causes (57%). Follow-up of PN was associated with a 4.6% relative reduction in cumulative lung cancer mortality (absolute mortality:FU: 4.33% vs. non-FU: 4.54%), more downstream testing (FU: 2.34 CTs/patient vs. non-FU: 1.01 CTs/patient), and an average increase of quality-adjusted life of seven days. Costs per quality adjusted life year (QALY) gained were $154,700 to follow-up the entire cohort and $129,800/QALY when only smokers were included.
Follow-up of PN incidentally detected in patients undergoing CCTA 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 QALY, especially in non-smokers.
PMCID: PMC4139449  PMID: 25015342
cost-effectiveness; comparative effectiveness; computer tomography angiography; computer-based model; health policy outcomes research
2.  Automatic Extraction of Comprehensive Cardiac CT Angiography Parameters: A Novel Program with High Accuracy and Efficiency 
Journal of Digital Imaging  2014;27(4):507-513.
We tested the accuracy and efficiency of a novel automated program capable of extracting 15 cardiac computed tomography angiography (CTA) parameters from clinical CTA reports. Five hundred cardiac CTA reports were retrospectively collected and processed. All reports were pre-populated with a structured template per guideline. The program extracted 15 parameters with high accuracy (97.3 %) and efficiency (84 s). This program may be used at other institutions with similar accuracy if its report format follows the Society of Cardiovascular Computed Tomography (SCCT) guideline recommendation.
PMCID: PMC4090403  PMID: 24526519
Algorithm; Database management; Data extraction; Efficiency; Radiation dose
3.  High-Risk Coronary Plaque at Coronary CT Angiography is Associated with Nonalcoholic Fatty Liver Disease, Independent of Coronary Plaque and Stenosis Burden: Results from the ROMICAT II Trial 
Radiology  2014;274(3):693-701.
To determine the association between nonalcoholic fatty liver disease (NAFLD) and the presence of high-risk coro-nary atherosclerotic plaque as assessed with coronary computed tomographic (CT) angiography.
Materials and Methods
This study was approved by the local ethics committees; informed consent was obtained. Patients randomized to the coronary CT angiography arm of the Rule Out Myocardial Infarction using Computer Assisted Tomography, or ROMICAT, II trial who underwent both nonenhanced CT to assess calcium score and contrast material-enhanced coronary CT angiography were included. Readers assessed coronary CT angiography images for the presence of coronary plaque, significant stenosis (≥50%), and high-risk plaque features (positive remodeling, CT attenuation < 30 HU, napkin-ring sign, spotty calcium). NAFLD was defined as hepatic steatosis at nonenhanced CT (liver minus spleen CT attenuation < 1 HU) without evidence of clinical liver disease, liver cirrhosis, or alcohol abuse. To determine the association between high-risk plaque and NAFLD, univariable and multivariable logistic regression analyses were performed, with high-risk plaque as a dependent variable and NAFLD, traditional risk factors, and extent of coronary atherosclerosis as independent variables.
Overall, 182 (40.9%) of 445 patients had CT evidence of NAFLD. High-risk plaque was more frequent in patients with NAFLD than in patients without NAFLD (59.3% vs 19.0%, respectively; P < .001). The association between NAFLD and high-risk plaque (odds ratio, 2.13; 95% confidence interval: 1.18, 3.85) persisted after adjusting for the extent and severity of coronary atherosclerosis and traditional risk factors.
NAFLD is associated with advanced high-risk coronary plaque, independent of traditional cardiovascular risk factors and the extent and severity of coronary artery disease.
PMCID: PMC4455680  PMID: 25369449
4.  Association of pericardial fat and coronary high-risk lesions as determined by cardiac CT 
Atherosclerosis  2012;222(1):129-134.
Pericardial adipose tissue (PAT) is a pathogenic fat depot associated with coronary atherosclerosis and cardiovascular events. We hypothesized that higher PAT is associated with coronary high-risk lesions as determined by cardiac CT.
We included 358 patients (38% female; median age 51 years) who were admitted to the ED with acute chest pain and underwent 64-slice CT angiography. The cardiac CT data sets were assessed for presence and morphology of CAD and PAT. Coronary high-risk lesions were defined as >50% luminal narrowing and at least two of the following characteristics: positive remodeling, low-density plaque, and spotty calcification. PAT was defined as any pixel with CT attenuation of −190 to −30 HU within the pericardial sac.
Based on cardiac CT, 50% of the patients (n = 180) had no CAD, 46% (n = 165) had CAD without high-risk lesions, and 13 patients had CAD with high-risk lesions. The median PAT in patients with high-risk lesions was significantly higher compared to patients without high-risk lesions and without any CAD (151.9 [109.0–179.4] cm3 vs. 110.0 [81.5–137.4] cm3, vs. 74.8 [58.2–111.7] cm3, respectively p = 0.04 and p < 0.0001). These differences remained significant after adjusting for traditional risk factors including BMI (all p < 0.05). The area under the ROC curve for the identification of high-risk lesions was 0.756 in a logistic regression model with PAT as a continuous predictor.
PAT volume is nearly twice as high in patients with high-risk coronary lesions as compared to those without CAD. PAT volume is significantly associated with high risk coronary lesion morphology independent of clinical characteristics and general obesity.
PMCID: PMC3738181  PMID: 22417843
Coronary artery disease; Cardiac CT angiography; Pericardial fat; Adipose tissue; Vulnerable plaque; High-risk lesions
5.  Effects of Losartan on Left Ventricular Hypertrophy and Fibrosis in Patients with Nonobstructive Hypertrophic Cardiomyopathy 
JACC. Heart failure  2013;1(6):480-487.
Structured Abstract
To evaluate the effects of losartan on left ventricular (LV) hypertrophy and fibrosis in patients with nonobstructive hypertrophic cardiomyopathy (HCM).
Despite evidence that myocardial hypertrophy and fibrosis are mediated by angiotensin II and are important determinants of morbidity and mortality in HCM, no prior study has evaluated the effects of angiotensin receptor blockers (ARBs) on LV hypertrophy and fibrosis with cardiac magnetic resonance imaging (CMR).
In double-blind fashion, 20 patients (3 women; age 51±13 years) with HCM were randomly assigned to receive placebo (n=9) or losartan 50 mg twice a day (n=11) for 1 year. CMR was performed at baseline and 1 year to measure LV mass and extent of fibrosis as assessed by late gadolinium enhancement (LGE).
There was a trend towards a significant difference in the percent change in LV mass (median [interquartile range], +5 [−4, +21] % on placebo vs. −5 [−11, −0.9] % on losartan; p=0.06). There was a significant difference in the percent change in extent of LGE, with the placebo group having larger increase (+31 ± 26 % on placebo vs. −23 ± 45 % on losartan; p=0.03).
This pilot study suggests attenuation of progression of myocardial hypertrophy and fibrosis by losartan in patients with nonobstructive HCM. Confirmation of these results in a larger trial is required to confirm a place for ARBs in the management of HCM.
PMCID: PMC3950308  PMID: 24621999
angiotensin II receptor blocker; cardiac magnetic resonance imaging; hypertrophic cardiomyopathy; late gadolinium enhancement; left ventricular fibrosis
6.  Effect of the 2010 task force criteria on reclassification of cardiovascular magnetic resonance criteria for arrhythmogenic right ventricular cardiomyopathy 
We sought to evaluate the effect of application of the revised 2010 Task Force Criteria (TFC) on the prevalence of major and minor Cardiovascular Magnetic Resonance (CMR) criteria for Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) versus application of the original 1994 TFC. We also assessed the utility of MRI to identify alternative diagnoses for patients referred for ARVC evaluation.
968 consecutive patients referred to our institution for CMR with clinical suspicion of ARVC from 1995 to 2010, were evaluated for the presence of major and minor CMR criteria per the 1994 and 2010 ARVC TFC. CMR criteria included right ventricle (RV) dilatation, reduced RV ejection fraction, RV aneurysm, or regional RV wall motion abnormalities. When quantitative measures of RV size and function were not available, and in whom abnormal size or function was reported, a repeat quantitative analysis by 2 qualified CMR physicians in consensus.
Of 968 patients, 220 (22.7%) fulfilled either a major or a minor 1994 TFC, and 25 (2.6%) fulfilled any of the 2010 TFC criterion. Among patients meeting any 1994 criteria, only 25 (11.4%) met at least one 2010 criterion. All patients who fulfilled a 2010 criteria also satisfied at least one 1994 criterion. Per the 2010 TFC, 21 (2.2%) patients met major criteria and 4 (0.4%) patients fulfilled at least one minor criterion. Eight patients meeting 1994 minor criteria were reclassified as satisfying 2010 major criteria, while 4 patients fulfilling 1994 major criteria were reclassified to only minor or no criteria under the 2010 TFC.
Eighty-nine (9.2%) patients had alternative cardiac diagnoses, including 43 (4.4%) with clinically significant potential ARVC mimics. These included cardiac sarcoidosis, RV volume overload conditions, and other cardiomyopathies.
Application of the 2010 TFC resulted in reduction of total patients meeting any diagnostic CMR criteria for ARVC from 22.7% to 2.6% versus the 1994 TFC. CMR identified alternative cardiac diagnoses in 9.2% of patients, and 4.4% of the diagnoses were potential mimics of ARVC.
PMCID: PMC4105392  PMID: 24996808
Arrhythmogenic right ventricular cardiomyopathy; 2010 task force criteria; Cardiovascular magnetic resonance
7.  CMR Quantification of Myocardial Scar Provides Additive Prognostic Information in Nonischemic Cardiomyopathy 
JACC. Cardiovascular imaging  2013;6(9):944-954.
This study sought to determine whether the extent of late gadolinium enhancement (LGE) can provide additive prognostic information in patients with a nonischemic dilated cardiomyopathy (NIDC) with an indication for implantable cardioverter-defibrillator (ICD) therapy for the primary prevention of sudden cardiac death (SCD).
Data suggest that the presence of LGE is a strong discriminator of events in patients with NIDC. Limited data exist on the role of LGE quantification.
The extent of LGE and clinical follow-up were assessed in 162 patients with NIDC prior to ICD insertion for primary prevention of SCD. LGE extent was quantified using both the standard deviation–based (2-SD) method and the full-width half-maximum (FWHM) method.
We studied 162 patients with NIDC (65% male; mean age: 55 years; left ventricular ejection fraction [LVEF]: 26 ± 8%) and followed up for major adverse cardiac events (MACE), including cardiovascular death and appropriate ICD therapy, for a mean of 29 ± 18 months. Annual MACE rates were substantially higher in patients with LGE (24%) than in those without LGE (2%). By univariate association, the presence and the extent of LGE demonstrated the strongest associations with MACE (LGE presence, hazard ratio [HR]: 14.5 [95% confidence interval (CI): 6.1 to 32.6; p < 0.001]; LGE extent, HR: 1.15 per 1% increase in volume of LGE [95% CI: 1.12 to 1.18; p < 0.0001]). Multivariate analyses showed that LGE extent was the strongest predictor in the best overall model for MACE, and a 7-fold hazard was observed per 10% LGE extent after adjustments for patient age, sex, and LVEF (adjusted HR: 7.61; p < 0.0001). LGE quantitation by 2-SD and FWHM both demonstrated robust prognostic association, with the highest MACE rate observed in patients with LGE involving >6.1% of LV myocardium.
LGE extent may provide further risk stratification in patients with NIDC with a current indication for ICD implantation for the primary prevention of SCD. Strategic guidance on ICD therapy by cardiac magnetic resonance in patients with NIDC warrants further study.
PMCID: PMC3952043  PMID: 23932642
cardiac magnetic resonance; implantable cardioverter-defibrillators; late gadolinium enhancement; nonischemic cardiomyopathy
9.  A Computed Tomography Based Coronary Lesion Score to Predict Acute Coronary Syndrome Among Patients With Acute Chest Pain and a Significant Coronary Stenosis on Coronary Computed Tomography Angiography 
The American Journal of Cardiology  2012;110(2):183-189.
We tested the hypothesis that the assessment of lesion morphology helped to detect acute coronary syndrome (ACS) during index hospitalization among patients with acute chest pain who had a significant stenosis on coronary computed tomography angiography (CTA). Patients who presented to the emergency department with chest pain but no objective signs of myocardial ischemia (non-diagnostic ECG and negative initial biomarkers) underwent CTA. CTA was analyzed for the degree and length of stenosis, plaque area and volume, remodeling index, CT attenuation of plaque, and spotty calcium in all patients with a significant stenosis (>50% in diameter) in CTA. ACS during the index hospitalization was determined by the panel of 2 physicians blinded to results of CTA. For lesion characteristics associated with ACS, we determined cutpoints optimized for diagnostic accuracy and created lesion scores. For each score, we determined odds ratio and discriminatory capacity for the prediction of ACS. Of the overall population of 368 patients, 34 had significant stenosis and among those 21 had ACS. Score A (remodeling index+spotty calcium: OR 3.5, 95%CI 1.2–10.1, AUC 0.734), B (remodeling index+spotty calcium+stenosis length: OR 4.6, 95%CI 1.6–13.7, AUC 0.824) and C (remodeling index+spotty calcium+stenosis length+volume of <90HU plaque: OR 3.4, 95%CI 1.5–7.9, AUC 0.833) were significantly associated with ACS. In conclusion, among patients presenting with acute chest pain and with a stenosis on coronary CTA, a CT-based score incorporating morphologic characteristics of coronary lesions had a good discriminatory value for the detection ACS during index hospitalization.
PMCID: PMC3383897  PMID: 22481015
cardiac computed tomography; coronary computed tomography angiography; acute coronary syndrome; coronary atherosclerotic plaque
10.  Feasibility of aortic valve assessment with low dose prospectively triggered adaptive systolic (PTAS) cardiac computed tomography angiography 
BMC Research Notes  2013;6:158.
Cardiac computed tomography angiography (CTA) is feasible for aortic valve evaluation, but retrospective gated protocols required high radiation doses for aortic valve assessment. A prospectively triggered adaptive systolic (PTAS) cardiac CT protocol was recently described in arrhythmia using second-generation dual-source CT. In this study, we sought to evaluate the feasibility of PTAS CTA to assess the aortic valve at a low radiation dose.
A retrospective cohort of 29 consecutive patients whom underwent PTAS protocols for clinical indications other than aortic valve assessment and whom also received echocardiography within 2 months of CT, was identified. Images were reviewed for aortic valve morphology (tricuspid/bicuspid/prosthetic) and stenosis (AS) by experienced blinded readers. Accuracy versus echocardiography and radiation doses were assessed.
All PTAS coronary CTAs were clinically diagnostic with 0 un-evaluable coronary segments. The accuracy of PTAS for aortic valve morphology was 92.6%, and for exclusion of severe AS was 93.1%. Two exams were un-evaluable for the aortic valve due to inadequate number of phases archived for interpretation. Total radiation dose was a median of 2.8 mSv (interquartile range 1.4–4.4 mSv).
PTAS CTA protocols using second-generation dual-source CT for aortic valve evaluation are feasible at low doses. This protocol should be investigated further in larger cohorts.
PMCID: PMC3640955  PMID: 23602055
Computed tomography angiography; Aortic stenosis; Low dose
12.  Clinical experiences of delayed contrast enhancement with cardiac computed tomography: case series 
BMC Research Notes  2013;6:2.
Myocardial delayed enhancement (MDE) by gadolinium-enhanced cardiac MRI is well established for myocardial scar assessment in ischemic and non-ischemic heart disease. The role of MDE by cardiac CT (CT-MDE) is not yet defined.
We reviewed all clinical cases of CT-MDE at a tertiary referral center to present the cases as a case series. All clinical cardiac CT exams which utilized CT-MDE imaging between January 1, 2005 and October 1, 2010 were collected as a series and their findings were also compared with available myocardial imaging to assess for myocardial abnormalities, including echocardiography (wall motion, morphology), cardiac MRI (delayed enhancement, morphology), SPECT MPI (perfusion defects). 5,860 clinical cardiac CT exams were performed during the study period. CT-MDE was obtained in 18 patients and was reported to be present in 9 patients. The indications for CT-MDE included ischemic and non-ischemic heart diseases. In segments positive for CT-MDE, there was excellent agreement of CT with other modalities: echocardiography (n=8) demonstrated abnormal morphology and wall motion (k=1.0 and k=0.82 respectively); prior MRI (n=2) demonstrated abnormal delayed enhancement (MR-MDE) (k=1.0); SPECT MPI (n=1) demonstrated fixed perfusion defects (k=1.0). In the subset of patients without CT-MDE, no abnormal segments were identified by echocardiography (n=8), MRI (n=1) and nuclear MPI (n=0).
CT-MDE was performed in rare clinical situations. The indications included both ischemic and non-ischemic heart disease and there was an excellent agreement between CT-MDE and abnormal myocardium by echocardiography, cardiac MRI, and nuclear MPI.
PMCID: PMC3548708  PMID: 23281746
13.  Using Keynote to Present Radiology Images 
Journal of Digital Imaging  2010;24(5):844-847.
Numerous articles have offered instructions for working with advanced radiology images in Microsoft PowerPoint (Redmond, WA); however, no articles have detailed instructions to do the same on alternative presentation software. Apple Macintosh (Cupertino, CA) computers are gaining popularity with many radiologists, due in part to the availability of a powerful, free, open-source Digital Imaging and Communications in Medicine (DICOM) viewing and manipulating software OsiriX ( Apple’s own presentation software, Keynote, is particularly effective in dealing with medical images and cine clips. This article demonstrates how to use Apple’s Keynote software to present radiology images and scrollable image stacks, without third-party add-on software. The article also illustrates how to compress media files and protect patient information in Keynote presentations. Lastly, it addresses the steps to converting between PowerPoint and Keynote file formats. Apple’s Keynote software enables quick and efficient addition of multiple static images or scrollable image stacks, compression of media files, and removal of patient information. These functions can be accomplished by inexperienced users with no software modifications.
PMCID: PMC3180549  PMID: 20978920
Computers in medicine; Radiology Information Systems (RIS); Radiology teaching file; Image processing; Image display; Productivity; Keynote
16.  Direct comparison of rest and adenosine stress myocardial perfusion CT with rest and stress SPECT 
We have recently described a technique for assessing myocardial perfusion using adenosine-mediated stress imaging (CTP) with dual source computed tomography. SPECT myocardial perfusion imaging (SPECT-MPI) is a widely utilized and extensively validated method for assessing myocardial perfusion. The aim of this study was to determine the level of agreement between CTP and SPECT-MPI at rest and under stress on a per-segment, per-vessel, and per-patient basis.
Forty-seven consecutive patients underwent CTP and SPECT-MPI. Perfusion images were interpreted using the 17 segment AHA model and were scored on a 0 (normal) to 3 (abnormal) scale. Summed rest and stress scores were calculated for each vascular territory and patient by adding corresponding segmental scores.
On a per-segment basis (n = 799), CTP and SPECT-MPI demonstrated excellent correlation: Goodman-Kruskall γ = .59 (P < .0001) for stress and .75 (P < .0001) for rest. On a per-vessel basis (n = 141), CTP and SPECT-MPI summed scores demonstrated good correlation: Pearson r = .56 (P < .0001) for stress and .66 (P < .0001) for rest. On a per-patient basis (n = 47), CTP and SPECT-MPI demonstrated good correlation: Pearson r = .60 (P < .0001) for stress and .76 (P < .0001) for rest.
CTP compares favorably with SPECT-MPI for detection, extent, and severity of myocardial perfusion defects at rest and stress.
PMCID: PMC2946891  PMID: 19936863
Adenosine; computed tomography (CT); ischemia; myocardial; sestamibi; SPECT

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