Christian Thilo

Publications of Christian Thilo

• Acute pulmonary embolism in patients with obstructive sleep apnoea: does it affect the severity of sleep-disordered breathing?

  Authors: Thomas M Berghaus, Christian Faul, Fabian Unterer, Christian Thilo, Wolfgang von Scheidt, Martin Schwaiblmair

  Sleep & breathing = Schlaf & Atmung. 12/2011;

  BACKGROUND: Acute pulmonary embolism (PE) may result in an increase in central venous pressure, which may contribute to pharyngeal narrowing by fluid accumulation in nuchal and peripharyngeal softBACKGROUND: Acute pulmonary embolism (PE) may result in an increase in central venous pressure, which may contribute to pharyngeal narrowing by fluid accumulation in nuchal and peripharyngeal soft tissues and therefore affect obstructive sleep apnoea (OSA). PURPOSE: This study aimed to clarify the impact of acute PE on the severity of sleep-disordered breathing in OSA patients. METHODS: Polysomnography (PSG) was performed in 15 OSA patients shortly after acute PE and again after 3 months of sufficient anticoagulation therapy. OSA remained untreated meanwhile. RESULTS: Acute PE did not significantly affect the apnoea-hypopnoea index (AHI). CONCLUSION: The diagnosis of OSA is representative in acute PE, as the transient increase of central venous pressure seems not to affect the AHI once the patients are clinical stable for PSG.

• CT signs of right ventricular dysfunction: prognostic role in acute pulmonary embolism.

  Authors: Doo Kyoung Kang, Christian Thilo, U Joseph Schoepf, J Michael Barraza, John W Nance, Gorka Bastarrika, Joseph A Abro, James G Ravenel, Philip Costello, Samuel Z Goldhaber

  JACC. Cardiovascular imaging. 08/2011; 4(8):841-9.

  The purpose of this study was to compare the prognostic role of various computed tomography (CT) signs of right ventricular (RV) dysfunction, including 3-dimensional ventricular volume measurements,The purpose of this study was to compare the prognostic role of various computed tomography (CT) signs of right ventricular (RV) dysfunction, including 3-dimensional ventricular volume measurements, to predict adverse outcomes in patients with acute pulmonary embolism (PE). Three-dimensional ventricular volume measurements based on chest CT have become feasible for routine clinical application; however, their prognostic role in patients with acute PE has not been assessed. We evaluated 260 patients with acute PE for the following CT signs of RV dysfunction obtained on routine chest CT: abnormal position of the interventricular septum, inferior vena cava contrast reflux, right ventricle diameter (RVD) to left ventricle diameter (LVD) ratio on axial sections and 4-chamber (4-CH) views, and 3-dimensional right ventricle volume (RVV) to left ventricle volume (LVV) ratio. Comorbidities and fatal and nonfatal adverse outcomes according to the MAPPET-3 (Management Strategies and Prognosis in Pulmonary Embolism Trial-3) criteria within 30 days were recorded. Fifty-seven patients (21.9%) had adverse outcomes, including 20 patients (7.7%) who died within 30 days. An RVD(axial)/LVD(axial) ratio >1.0 was not predictive for adverse outcomes. On multivariate analysis (adjusting for comorbidities), abnormal position of the interventricular septum (hazard ratio [HR]: 2.07; p = 0.007), inferior vena cava contrast reflux (HR: 2.57; p = 0.001), RVD(4-CH)/LVD(4-CH) ratio >1.0 (HR: 2.51; p = 0.009), and RVV/LVV ratio >1.2 (HR: 4.04; p < 0.001) were predictive of adverse outcomes, whereas RVD(4-CH)/LVD(4-CH) ratio >1.0 (HR: 3.68; p = 0.039) and RVV/LVV ratio >1.2 (HR: 6.49; p = 0.005) were predictive of 30-day death. Three-dimensional ventricular volume measurement on chest CT is a predictor of early death in patients with acute PE, independent of clinical risk factors and comorbidities. Abnormal position of the interventricular septum, inferior vena cava contrast reflux, and RVD(4-CH)/LVD(4-CH) ratio are predictive of adverse outcomes, whereas RVD(axial)/LVD(axial) ratio >1.0 is not.

• Can non-calcified coronary artery plaques be detected on non-contrast CT calcium scoring studies?

  Authors: Christian Thilo, Mulugeta Gebregziabher, Florian B Mayer, Thomas M Berghaus, Peter L Zwerner, U Joseph Schoepf

  Academic radiology. 07/2011; 18(7):858-65.

  Coronary computed tomographic (CT) angiography has been shown to detect noncalcified coronary artery plaque. Depending on tissue composition, noncalcified plaque differs in CT attenuation from bloodCoronary computed tomographic (CT) angiography has been shown to detect noncalcified coronary artery plaque. Depending on tissue composition, noncalcified plaque differs in CT attenuation from blood and epicardial fat. The aim of this study was to determine whether noncalcified plaque can be visually detected on non-contrast-enhanced CT calcium scoring studies. A total of 106 patients (40 women; mean age, 59 years) who underwent coronary calcium scoring, coronary CT angiography, and quantitative catheter angiography were prospectively investigated. Two blinded observers independently reviewed calcium scoring studies for positive vascular remodeling and hypoattenuation within the vessel wall, suggestive of noncalcified plaque. Findings on calcium scoring studies were compared with those on coronary CT angiography and quantitative catheter angiography. The mean Agatston score was 515.8 ± 826.8. Overall interobserver agreement for the identification of noncalcified lesions was substantial (κ = 0.69). Observer 1 and observer 2 identified 21 and 17 patients, respectively, with 38 and 35 lesions suggestive of noncalcified plaque. Coronary CT angiography confirmed noncalcified plaque in 33 of 38 (86.8%; observer 1) and 31 of 35 (88.6%; observer 2) lesions. Thus, the overall positive predictive value for correct identification of noncalcified plaque on calcium scoring studies was 0.88, although overall sensitivity was low at 0.39. Noncalcified plaque can be visually detected on calcium scoring studies. Review of calcium scoring studies for features of noncalcified plaque may enhance the identification of patients with more active disease and higher cardiovascular risk.

• As time goes by?: the fallacy of thrombolysis in STEMI networks.

  Authors: Wolfgang von Scheidt, Christian Thilo

  Clinical research in cardiology : official journal of the German Cardiac Society. 06/2011; 100(10):867-77.

  Primary percutaneous coronary intervention (PPCI) is superior to thrombolysis (TL) as reperfusion therapy in ST-elevation myocardial infarction (STEMI). TL is a rapidly available, but semi-effectivePrimary percutaneous coronary intervention (PPCI) is superior to thrombolysis (TL) as reperfusion therapy in ST-elevation myocardial infarction (STEMI). TL is a rapidly available, but semi-effective therapy (effective reperfusion in 50% of patients only), whereas PPCI is a potentially delayed, but highly effective therapy (effective reperfusion in >90%). Since TL loses its efficacy beyond 2-3 h after symptom onset, it is a significant reperfusion alternative to PPCI in early presenters only. The individual decision to treat an early presenter with PPCI or TL requires the evaluation of the time delay between potential start of TL or PPCI, the PCI-related delay (PRD). PRD is greatest, if TL is given in the prehospital setting. Until now, prehospital TL as the most rapidly available reperfusion strategy has failed to demonstrate any prognostic or even any other relevant benefit compared to PPCI in any subgroup of patients, even with time delays for PPCI of up to several hours. On average, a median PRD of at least 90-120 min can be considered a time corridor of prognostic superiority of PPCI over TL. This is already achieved in contemporary registries and myocardial infarction networks.Therefore, the efforts should not focus on the implementation of a dual reperfusion strategy (PPCI, and prehospital TL in selected cases) in established or upcoming myocardial infarction networks, but concentrate on the availability of PPCI in less than 2 h. TL, as rapid as possible, i.e. prehospital, is a vital treatment option in case of non-existing PPCI facilities within a median time limit of 2 h or even more, a scenario not existing or easily to eliminate in European countries by implementing well organized myocardial infarction networks. This is the mission to be accomplished.

• Coronary atherosclerosis in African American and white patients with acute chest pain: characterization with coronary CT angiography.

  Authors: John W Nance, Fabian Bamberg, U Joseph Schoepf, Doo Kyoung Kang, J Michael Barraza, Joseph A Abro, Gorka Bastarrika, Gary F Headden, Philip Costello, Christian Thilo

  Radiology. 06/2011; 260(2):373-80.

  To use coronary computed tomographic (CT) angiography to compare the prevalence, extent, and composition of coronary atherosclerotic lesions in African American and white patients with acute chestTo use coronary computed tomographic (CT) angiography to compare the prevalence, extent, and composition of coronary atherosclerotic lesions in African American and white patients with acute chest pain. The institutional review board waived the requirement for informed consent for this retrospective, HIPAA-compliant matched-cohort study. The authors analyzed the CT angiographic data of 301 patients (150 consecutive African American patients; 151 white control patients; mean age, 55 years ± 11 [standard deviation]; 33% male) with acute chest pain. Each coronary artery segment was evaluated for presence of atherosclerotic plaque, plaque composition (calcified, noncalcified, or mixed), and stenosis. In addition, the noncalcified plaque volume was quantified by using a threshold-based automated algorithm. The presence and extent of atherosclerotic plaque were compared between the groups by using univariate and multivariate regression analyses. While there was no significant difference between the African American and white patients with respect to presence of any plaque (118 [79%] of 150 vs 112 [74%] of 151 patients, respectively; P = .36) or presence of stenosis (26 [17%] vs 37 [24%] patients, respectively; P = .13), the African American patients had a significantly higher prevalence (96 [64%] vs 62 [41%] patients, respectively; P < .001) and volume (median volume, 2.2 vs 1.4 mL, respectively; P < .001) of noncalcified plaque, independent of diabetes and other cardiovascular risk factors (odds ratio, 2.45; 95% confidence interval: 1.52, 4.04). In contrast, the African American patients had a lower prevalence of calcified plaque (39 [26%] vs 68 [45%] white patients, P = .001). Study results suggest that atherosclerotic plaque burden and composition, as measured by using coronary CT angiography, differ between African American and white patients, with relatively more noncalcified disease in African Americans and more calcified disease in white individuals. Further research is warranted to determine whether CT plaque characterization can improve cardiac risk prediction in African Americans.

• Accuracy of coronary artery stenosis detection with CT versus conventional coronary angiography compared with composite findings from both tests as an enhanced reference standard.

  Authors: J Matthias Kerl, U Joseph Schoepf, Peter L Zwerner, Ralf W Bauer, Joseph A Abro, Christian Thilo, Thomas J Vogl, Christopher Herzog

  European radiology. 05/2011; 21(9):1895-903.

  To prospectively compare the accuracy of coronary CT angiography (CCTA) and conventional coronary angiography (CCA) for stenosis detection using composite findings from both tests as an enhancedTo prospectively compare the accuracy of coronary CT angiography (CCTA) and conventional coronary angiography (CCA) for stenosis detection using composite findings from both tests as an enhanced reference standard. One hundred thirteen patients underwent CCTA and CCA. Per-segment and per-patient accuracy of CCTA compared with initial CCA interpretation were determined. Angiographers were then unblinded to the CCTA results and re-evaluation of the CCA studies was performed with knowledge of CCTA findings, which was used as an enhanced reference standard to compare the diagnostic accuracy of CCTA versus CCA. When using the enhanced reference standard instead of initial CCA interpretation, CCTA accuracy for identifying segments (patients) with ≥50% stenosis increased from 97.7% (96.5%) to 98.1% (98.2%), sensitivity from 90.5% (100%) to 90.8% (100%), and specificity from 98.4% (94.3%) to 98.9% (97.1%). CCTA identified six segments and two patients with stenoses ≥50% missed on initial CCA interpretation. Compared with the enhanced reference standard the accuracies of CCTA and of initial CCA interpretation were not different (p = 0.87). CCTA compares favourably with CCA for stenosis detection. Use of a composite reference standard combining findings from both tests can control for the effect of false-negative CCA results when evaluating the accuracy of CCTA.

• Computer-aided detection of pulmonary embolism at CT pulmonary angiography: can it improve performance of inexperienced readers?

  Authors: Kevin N Blackmon, Charles Florin, Luca Bogoni, Joshua W McCain, James D Koonce, Heon Lee, Gorka Bastarrika, Christian Thilo, Philip Costello, Marcos Salganicoff, U Joseph Schoepf

  European radiology. 01/2011; 21(6):1214-23.

  To evaluate the effect of a computer-aided detection (CAD) algorithm on the performance of novice readers for detection of pulmonary embolism (PE) at CT pulmonary angiography (CTPA). We included CTPATo evaluate the effect of a computer-aided detection (CAD) algorithm on the performance of novice readers for detection of pulmonary embolism (PE) at CT pulmonary angiography (CTPA). We included CTPA examinations of 79 patients (50 female, 52 ± 18 years). Studies were evaluated by two independent inexperienced readers who marked all vessels containing PE. After 3 months all studies were reevaluated by the same two readers, this time aided by CAD prototype. A consensus read by three expert radiologists served as the reference standard. Statistical analysis used χ(2) and McNemar testing. Expert consensus revealed 119 PEs in 32 studies. For PE detection, the sensitivity of CAD alone was 78%. Inexperienced readers' initial interpretations had an average per-PE sensitivity of 50%, which improved to 71% (p < 0.001) with CAD as a second reader. False positives increased from 0.18 to 0.25 per study (p = 0.03). Per-study, the readers initially detected 27/32 positive studies (84%); with CAD this number increased to 29.5 studies (92%; p = 0.125). Our results suggest that CAD significantly improves the sensitivity of PE detection for inexperienced readers with a small but appreciable increase in the rate of false positives.

• Evaluation of plaques and stenosis.

  Authors: Elisabeth Arnoldi, Thomas Henzler, Gorka Bastarrika, Christian Thilo, Konstantin Nikolaou, U Joseph Schoepf

  Radiologic clinics of North America. 07/2010; 48(4):729-44.

  Cardiac CT scan has emerged from a research tool to a widely used clinical modality in the diagnostic management of coronary artery disease. Based on evidence of numerous clinical studies coronary CTCardiac CT scan has emerged from a research tool to a widely used clinical modality in the diagnostic management of coronary artery disease. Based on evidence of numerous clinical studies coronary CT angiography (cCTA) has emerged as a fast, accurate, and noninvasive alternative to conventional angiography in selected patient populations. A major strength of cCTA is its ability to combine information on the coronary artery anatomy, the vessel lumen, and atherosclerotic lesions. Recent investigations on the application of cCTA in myocardial perfusion imaging suggest that cCTA may allow analysis of the hemodynamic relevance of detected stenosis. Data is accumulating that supports its relevance for patient management and outcome. This article examines the role of cCTA for the evaluation of plaques and stenosis.

• Reproducibility of CT signs of right ventricular dysfunction in acute pulmonary embolism.

  Authors: Doo Kyoung Kang, Luis Ramos-Duran, U Joseph Schoepf, Andrew M Armstrong, Joseph A Abro, James G Ravenel, Christian Thilo

  AJR. American journal of roentgenology. 06/2010; 194(6):1500-6.

  The purpose of our study was to determine the interobserver reproducibility of CT findings of right ventricular (RV) dysfunction in pulmonary embolism (PE). Two experienced observers independentlyThe purpose of our study was to determine the interobserver reproducibility of CT findings of right ventricular (RV) dysfunction in pulmonary embolism (PE). Two experienced observers independently and retrospectively evaluated pulmonary CT angiography (CTA) studies of 50 patients with acute PE for the following signs: bowing of the interventricular septum, inferior vena cava (IVC) contrast medium reflux, RV diameter (RVD)/left ventricular diameter (LVD) ratio on axial sections and four-chamber (4-CH) views, and RV volume (RVV)/left ventricular volume (LVV) ratio. Analysis used kappa statistics, Spearman's rank correlation, and Bland-Altman statistics. The two observers had fair to moderate agreement (kappa = 0.32-0.44) for septal bowing and moderate to good agreement (kappa = 0.57-0.68) for diagnosing IVC reflux. The Spearman's rank correlation coefficients for RVD(axial)/LVD(axial) ratio and RVD(4-CH)/LVD(4-CH) ratio between the two observers were 0.88 (p < 0.001) and 0.85 (p < 0.001), respectively. On Bland-Altman analysis, the mean differences for RVD(axial)/LVD(axial) ratio and RVD(4-CH)/LVD(4-CH) ratio were 0.014 (+/- 0.195) and 0.001 (+/- 0.242), respectively. The correlation coefficient for RVV/LVV ratio was 0.93 (p < 0.001), and the mean difference was 0.033 (+/- 0.229). Considerable differences exist in the interobserver reproducibility of CT findings of RV dysfunction on pulmonary CTA in patients with acute PE. Cardiac chamber measurements are more reproducible than septal bowing and IVC reflux. Volumetric determination of the RVV/LVV ratio is the least user dependent and most reproducible.

• Automated computer-aided stenosis detection at coronary CT angiography: initial experience.

  Authors: Elisabeth Arnoldi, Mulugeta Gebregziabher, U Schoepf, Roman Goldenberg, Luis Ramos-Duran, Peter Zwerner, Konstantin Nikolaou, Maximilian Reiser, Philip Costello, Christian Thilo

  European radiology. 11/2009;

  OBJECTIVE: To evaluate the performance of a computer-aided algorithm for automated stenosis detection at coronary CT angiography (cCTA). METHODS: We investigated 59 patients (38 men, mean age 58 +/-OBJECTIVE: To evaluate the performance of a computer-aided algorithm for automated stenosis detection at coronary CT angiography (cCTA). METHODS: We investigated 59 patients (38 men, mean age 58 +/- 12 years) who underwent cCTA and quantitative coronary angiography (QCA). All cCTA data sets were analyzed using a software algorithm for automated, without human interaction, detection of coronary artery stenosis. The performance of the algorithm for detection of stenosis of 50% or more was compared with QCA. RESULTS: QCA revealed a total of 38 stenoses of 50% or more of which the algorithm correctly identified 28 (74%). Overall, the automated detection algorithm had 74%/100% sensitivity, 83%/65% specificity, 46%/58% positive predictive value, and 94%/100% negative predictive value for diagnosing stenosis of 50% or more on per-vessel/per-patient analysis, respectively. There were 33 false positive detection marks (average 0.56/patient), of which 19 were associated with stenotic lesions of less than 50% on QCA and 14 were not associated with an atherosclerotic surrogate. CONCLUSION: Compared with QCA, the automated detection algorithm evaluated has relatively high accuracy for diagnosing significant coronary artery stenosis at cCTA. If used as a second reader, the high negative predictive value may further enhance the confidence of excluding significant stenosis based on a normal or near-normal cCTA study.

• Correlation of regional distribution and morphological pattern of calcification at CT coronary artery calcium scoring with non-calcified plaque formation and stenosis.

  Authors: Christian Thilo, Mulugeta Gebregziabher, Florian Mayer, Peter Zwerner, Philip Costello, U Schoepf

  European radiology. 10/2009;

  OBJECTIVE: To investigate whether regional calcification patterns at CT coronary artery calcium scoring (CCS) correlate with stenosis and non-calcified plaque formation. METHODS: We studied 106OBJECTIVE: To investigate whether regional calcification patterns at CT coronary artery calcium scoring (CCS) correlate with stenosis and non-calcified plaque formation. METHODS: We studied 106 patients with quantitative catheter angiography (QCA), CCS, and coronary CT angiography (cCTA). CCS was determined globally and for each artery separately. The morphological pattern of each calcification was classified as calcified nodule, shell-like, or diffuse. cCTA studies were evaluated for non-calcified plaque. The global and regional CCS and the calcification pattern were correlated with stenosis >/=50% and non-calcified plaque. RESULTS: A total of 48/106 patients had stenosis >/=50% on QCA. There was weak correlation (r = 0.36) of the global CCS with stenosis. Correlation was stronger per vessel (r = 0.55-r = 0.67). Shell-like and diffuse calcifications were significantly (p = 0.0001) more frequently associated with >/=50% stenosis and non-calcified plaque (p = 0.04) than calcified nodules. CONCLUSION: As shown before, the global CCS does not correlate well with stenosis. However, regional calcium distribution and specific patterns of calcification are correlated with stenosis and non-calcified plaque. Thus, the specificity of CT calcium scoring for identifying individuals with obstructive disease could be improved by vessel-based rather than global quantification of calcium and by differentiating specific morphological patterns of calcification.

• Cardiac CT in the assessment of acute chest pain in the emergency department.

  Authors: Gorka Bastarrika, Christian Thilo, Gary F Headden, Peter L Zwerner, Philip Costello, U Joseph Schoepf

  AJR. American journal of roentgenology. 09/2009; 193(2):397-409.

  OBJECTIVE: The purpose of this article is to describe the current role of ECG-synchronized CT in the evaluation of patients with acute chest pain (triple rule-out) in the emergency department. WeOBJECTIVE: The purpose of this article is to describe the current role of ECG-synchronized CT in the evaluation of patients with acute chest pain (triple rule-out) in the emergency department. We discuss clinical contexts of the chest pain algorithm, technical improvements that have enabled CT to attain its current role for this application, scan protocols and radiation considerations, the evidence base regarding diagnostic and prognostic performance, and initial data on the cost-effectiveness of this promising emerging test. CONCLUSION: Currently available evidence suggests that CT-based approaches with modern scan technology are safe, accurate, and potentially cost-saving, although large-scale clinical trials are needed to ascertain the precise role of CT in the evaluation of acute chest pain.

• Noncalcified atherosclerotic plaque burden at coronary CT angiography: a better predictor of ischemia at stress myocardial perfusion imaging than calcium score and stenosis severity.

  Authors: Ralf W Bauer, Christian Thilo, Salvatore A Chiaramida, Thomas J Vogl, Philip Costello, U Joseph Schoepf

  AJR. American journal of roentgenology. 09/2009; 193(2):410-8.

  OBJECTIVE: The purpose of this study was to examine the relation between the coronary CT angiographic findings of calcified and noncalcified plaque burden and stenosis severity and the myocardialOBJECTIVE: The purpose of this study was to examine the relation between the coronary CT angiographic findings of calcified and noncalcified plaque burden and stenosis severity and the myocardial perfusion imaging finding of ischemia. MATERIALS AND METHODS: Seventy-two patients (41 men, 31 women; mean age, 56 years) underwent coronary CT angiography and stress-rest SPECT myocardial perfusion imaging. Calcium scoring was performed. Coronary CT angiograms were analyzed for stenosis and noncalcified or mixed plaque. A plaque analysis tool was used to calculate the volume of noncalcified plaque components. SPECT images were analyzed for perfusion defects. Data were analyzed per patient and per vessel. RESULTS: A total of 53 purely noncalcified, 50 mixed, and 201 purely calcified plaques were detected. Forty-five stenoses were rated > or = 50%, 19 of those being > or = 70%. Myocardial perfusion imaging depicted perfusion defects in 37 vessels (13%) in 24 patients (18 reversible, 19 fixed defects). Vessels with > or = 50% stenosis had significantly (p = 0.0009) more perfusion defects in their supplied territories (11 with, 22 without perfusion defects) than did vessels without significant lesions (26 with, 229 without perfusion defects). In vessel-based analysis, the sensitivity of coronary CT angiography in prediction of any perfusion defect on myocardial perfusion images was 30% with 91% specificity, 33% positive predictive value, and 90% negative predictive value. Between vessels with and those without perfusion defects, there was no significant difference in Agatston or calcium volume score (p = 0.25), but there was a significant difference in noncalcified plaque volume (44 +/- 77 vs 19 +/- 58 mm(3); p = 0.03). Multiple stepwise regression analysis showed noncalcified plaque volume was the only significant predictor of ischemia (p = 0.01). CONCLUSION: At coronary CT angiography, noncalcified plaque burden is a better predictor of the finding of myocardial ischemia at stress myocardial perfusion imaging than are calcium score and degree of stenosis.

• Reproducibility of automated noncalcified coronary artery plaque burden assessment at coronary CT angiography.

  Authors: Kevin N Blackmon, Julian Streck, Christian Thilo, Gorka Bastarrika, Philip Costello, U Joseph Schoepf

  Journal of thoracic imaging. 05/2009; 24(2):96-102.

  PURPOSE: To evaluate the accuracy and effect on interreader reproducibility of automated versus manual volumetric quantification of noncalcified coronary artery plaque burden at coronary computedPURPOSE: To evaluate the accuracy and effect on interreader reproducibility of automated versus manual volumetric quantification of noncalcified coronary artery plaque burden at coronary computed tomography angiography. MATERIALS AND METHODS: Thirty-seven patients underwent 64-slice coronary computed tomography angiography. Two experienced observers in consensus evaluated each study and identified 40 noncalcified coronary artery plaques. Also in consensus, they performed manual, 3-dimensional planimetric measurements on each plaque as the reference standard. The same 2 observers then performed volumetric measurements on each plaque using a threshold-based automated volumetry automated plaque analysis algorithm. Two different, less experienced observers also performed both, manual and automated measurements of each plaque, first independently and then in consensus. Spearman rank correlation was used to determine association between variables. RESULTS: Automated volumetry was successfully performed on each plaque. There was excellent (R=0.920) correlation between the expert manual measurements (average plaque burden=33.58 mm(3)+/-18.16) and automated plaque volumetry (35.64 mm(3)+/-16.42). For the less experienced observers, there was better correlation with expert manual measurements using automated plaque volumetry (R=0.885) than with manual measurements (R=0.854). Interreader correlation for volume measurements by the 2 less experienced observers without and with use of the automated plaque analysis algorithm significantly (P<0.001) increased from R=0.781 to R=0.919. CONCLUSIONS: Compared with expert manual measurements, automated plaque volumetry enables accurate quantification of noncalcified plaque burden. Reproducibility of plaque measurements between different observers is improved. Use of such automated plaque analysis algorithms should facilitate fast, objective and reproducible assessment of noncalcified plaque burden for risk stratification and therapeutic monitoring.

• Coronary artery plaque formation at coronary CT angiography: morphological analysis and relationship to hemodynamics.

  Authors: Benedetta Enrico, Pal Suranyi, Christian Thilo, Lorenzo Bonomo, Philip Costello, U Schoepf

  European radiology. 11/2008;

  We aimed to demonstrate that coronary CT angiography (cCTA) can be used to non-invasively study the effect of hemodynamic factors in the pathophysiology of plaque formation. cCTA data of 73 patientsWe aimed to demonstrate that coronary CT angiography (cCTA) can be used to non-invasively study the effect of hemodynamic factors in the pathophysiology of plaque formation. cCTA data of 73 patients were analyzed. All detected plaques were classified according to location (bifurcation, non-branching segment), configuration (eccentric, concentric), orientation (myocardial, lateral, epicardial side of the vessel wall), and composition (calcified, mixed, non-calcified). Bifurcation lesions were further characterized using the Medina classification. Of 382 plaques, 8.1% were in the LM, 46.3% in the LAD, 18.3% in the LCx, and 25.9% in the RCA. Also, 25.1% were completely calcified, 72.3% were mixed, and 2.6% were purely non-calcified. Of the plaques, 51.3% were bifurcation lesions. The most frequent (40%) Medina pattern was 1.1.0 (lesion starts before, extends beyond bifurcation, sparing the side branch). Eighty percent of plaques were eccentric. A significant (p < 0.01) majority (55%) were on the myocardial side, while 17.3% were lateral, and 27.7% epicardial. Of all non-calcified and mixed plaques, 45.1% (p < 0.01) were myocardial, whereas only 14.3% were lateral, 20.6% epicardial, and 19.9% concentric. We conclude that cCTA can non-invasively study the effect of vascular hemodynamics, such as turbulent flow (bifurcations) and low shear stress (myocardial vessel wall), on the distribution and composition of atherosclerotic plaque deposition.

• Integrated assessment of coronary anatomy and myocardial perfusion using a retractable SPECT camera combined with 64-slice CT: initial experience.

  Authors: Christian Thilo, U Schoepf, Leonie Gordon, Salvatore Chiaramida, Jill Serguson, Philip Costello

  European radiology. 10/2008;

  We evaluated a prototype SPECT system integrated with multidetector row CT (MDCT) for obtaining complementary information on coronary anatomy and hemodynamic lesion significance. Twenty-fiveWe evaluated a prototype SPECT system integrated with multidetector row CT (MDCT) for obtaining complementary information on coronary anatomy and hemodynamic lesion significance. Twenty-five consecutive patients with known or suspected coronary artery disease (CAD) underwent routine SPECT myocardial perfusion imaging (MPI). All patients also underwent repeat MPI with a mobile SPECT unit which could be attached to a 64-slice MDCT system. Coronary CT angiography (cCTA) was performed without repositioning the patient. Investigational MPI was compared with routine MPI for detection of myocardial perfusion defects (PD). Two observers diagnosed presence or absence of CAD based on MPI alone, cCTA alone, and based on combined MPI and cCTA with fused image display. In 22/24 patients investigative MPI corresponded with routine MPI (r = 0.80). Stenosis >/= 50% at cCTA was detected in 6/24 patients. Six out of 24 patients had PD at regular MPI. Three of these six patients had no significant stenosis at cCTA. Three out of 19 patients with normal MPI studies had significant stenosis at cCTA. Our initial experience indicates that the integration of SPECT MPI with cCTA is technically feasible and enables the comprehensive evaluation of coronary artery anatomy and myocardial perfusion with a single instrumental setup.

• Posttraumatic pseudoaneurysm of the left ventricle: multimodality assessment.

  Authors: Christian Thilo, U Joseph Schoepf, John S Ikonomidis

  European heart journal. 08/2008; 29(14):1792.

• Right heart: split-bolus injection of diluted contrast medium for visualization at coronary CT angiography.

  Authors: J Matthias Kerl, James G Ravenel, Shaun A Nguyen, Pal Suranyi, Christian Thilo, Philip Costello, Werner Bautz, U Joseph Schoepf

  Radiology. 05/2008; 247(2):356-64.

  PURPOSE: To retrospectively compare a split-bolus contrast medium injection protocol with a biphasic and a monophasic protocol in terms of visualization of the right and left heart, contrastPURPOSE: To retrospectively compare a split-bolus contrast medium injection protocol with a biphasic and a monophasic protocol in terms of visualization of the right and left heart, contrast medium-related streak artifacts, and level of attenuation in the cardiac chambers and coronary arteries at coronary computed tomographic (CT) angiography. MATERIALS AND METHODS: The human research committee approved this HIPAA-compliant study and waived informed consent. Seventy-five patients had undergone 64-section coronary CT angiography: 25 were injected by using a monophasic, contrast-medium-only protocol with a single-syringe injector; 25 were injected by using a biphasic protocol with a dual-syringe injector; and 25 were injected by using a split-bolus protocol with a dual-syringe injector and an initial bolus of contrast medium followed by 50 mL of a 70%:30% saline-to-contrast medium mixture and a 30-mL saline chaser. Two radiologists rated the visualization of right and left heart structures and the degree of streak artifacts. One observer performed attenuation measurements of the cardiac chambers and of the coronary arteries. Data were analyzed with one-way analysis of variance and Duncan post-hoc multiple comparison procedures. RESULTS: Data for 27 women and 48 men (mean age, 62 years) were included. Mean contrast medium attenuation in the right heart was significantly (P < .001) higher in the split-bolus group than in the biphasic injection group but was significantly (P < .001) lower than in the monophasic injection group. For the left heart and the coronary arteries, there were no significant differences among the three groups. Artifacts occurred less frequently (P < .001) in the biphasic and split-bolus groups than in the monophasic group. Visualization of right heart structures was rated significantly (P < .05) better in the split-bolus group than in the two other groups, while there was no difference for visualization of left heart structures. CONCLUSION: Split-bolus injection provides sufficient attenuation for visualization of the right heart, while streak artifacts from high-attenuation contrast material can generally be avoided and arterial attenuation is maintained.

• Replacing diagnostic catheterization with coronary CT angiography: the final frontier.

  Authors: U Joseph Schoepf, Pal Suranyi, Christian Thilo, Philip Costello, Peter L Zwerner

  European heart journal. 11/2007; 28(19):2305-6.

• Coronary CTA: indications, patient selection, and clinical implications.

  Authors: Christian Thilo, Mark Auler, Peter Zwerner, Philip Costello, U Joseph Schoepf

  Journal of thoracic imaging. 03/2007; 22(1):35-9.

  Recent technical advancements of modern multislice computed tomography scanners including improved temporal and spatial resolution allow for the evaluation of cardiac patients. These modernRecent technical advancements of modern multislice computed tomography scanners including improved temporal and spatial resolution allow for the evaluation of cardiac patients. These modern techniques have been applied to bypass imaging, assessment of pulmonary veins following ablative therapy, congenital and acquired anatomic abnormalities, and also the evaluation of coronary artery disease. Cardiac computed tomography angiography is a valuable tool for patients with equivocal stress test results or inconclusive echocardiography in patients with intermediate likelihood of coronary artery disease. Future applications of this study include coronary plaque imaging, triage of patients with chest pain in the emergency room, and evaluation of myocardial viability.