Yeong Shyan Lee

Publications of Yeong Shyan Lee

• CT detection of myocardial blood volume deficits: dual-energy CT compared with single-energy CT spectra.

  Authors: Elisabeth Arnoldi, Yeong Shyan Lee, Balazs Ruzsics, Markus Weininger, J Reid Spears, Christopher P Rowley, Salvatore A Chiaramida, Philip Costello, Maximilian F Reiser, U Joseph Schoepf

  Journal of cardiovascular computed tomography. 11/2011; 5(6):421-9.

  The performance of dual-energy CT (DECT) for the detection of myocardial blood volume deficits has not systematically been compared with single-energy CT (SCT) spectra. We evaluated the accuracy forThe performance of dual-energy CT (DECT) for the detection of myocardial blood volume deficits has not systematically been compared with single-energy CT (SCT) spectra. We evaluated the accuracy for detection of myocardial blood volume deficits in DECT and SCT compared with 99m-Tc-Sestamibi-SPECT (single-photon emission CT) during rest and stress. 47 patients underwent rest/stress SPECT myocardial perfusion imaging and cardiac DECT on a dual-source CT scanner. The A- and B-tubes were operated with 140 kV and 80 kV/100 kV, respectively. DECT raw data were reconstructed by (1) only using high-energy (140 kV) CT spectra, (2) only using low-energy (80 kV/100 kV) CT spectra, (3) merging data (30% low- and 70% high-energy CT spectra), and (4) DECT-based iodine maps. Two independent, blinded observers analyzed all CT data according to each of the 4 reconstruction strategies for myocardial blood volume deficits. Specificity and positive predictive values were relatively similar between the 4 reconstruction strategies, with highest specificity (98%) of SCT datasets based on 140 kV for mixed perfusion deficits seen on SPECT. DECT iodine maps showed highest sensitivity, negative predictive value, and accuracy of 91%, 97%, and 93%, respectively, for mixed perfusion deficits. Analysis with receiver operating characteristics showed highest area under the curve values (0.84-0.93) with the use of DECT iodine maps in the detection of purely fixed and mixed perfusion deficits. DECT iodine maps show superior performance for the detection of fixed and mixed perfusion deficits compared with SCT spectra.

• Reproducibility of left and right ventricular mass measurements with cardiac CT.

  Authors: Florian Schwarz, Richard Takx, U Joseph Schoepf, Yeong Shyan Lee, Balazs Ruzsics, Eva Maria Gassner, Salvatore Chiaramida, Thomas Henzler

  Journal of cardiovascular computed tomography. 08/2011; 5(5):317-24.

  Cardiac CT provides volumetric data that enables characterization of the myocardium. We evaluated intraobserver, interobserver, and interstudy reproducibility of left ventricular (LV) and rightCardiac CT provides volumetric data that enables characterization of the myocardium. We evaluated intraobserver, interobserver, and interstudy reproducibility of left ventricular (LV) and right ventricular (RV) mass quantification with cardiac CT. Thirty-eight patients who underwent cardiac CT twice within 365 days were included in this analysis. Functional reconstructions in 10% steps throughout the R-R interval and axial 1.5-mm sections were used. Semiautomatic contour detection was used to trace epicardial and endocardial borders in all cardiac phases for calculation of LV and RV ejection fraction, end-diastolic volume, end-systolic volume, cardiac output, stroke volume, and ventricular mass. For each study 2 observers measured LV and RV mass twice. LV mass parameters derived from semiautomatic contour detection algorithm had excellent intraobserver (r = 1.00), interobserver (r = 0.99), and interstudy (r = 0.99) reproducibility (P < 0.0001). Average end-diastolic LV mass was 146.2 ± 42.9 g at the first CT study and 146.8 ± 44.4 g at the second study. For measuring RV mass, reproducibility was good on all levels (r = 0.78, r = 0.78, and r = 0.68, respectively, with an average end-diastolic mass of 25.7 ± 5.8 g at the first study and 24.4 ± 4.8 g at the second study. Quantification of LV mass at cardiac CT with the threshold-based, region-growing semiautomatic segmentation analysis software evaluated here is highly observer independent and reproducible. This largely holds true for the estimation of RV mass as well; however, further improvements are needed to optimize reproducibility for RV mass quantification.

• Anomalous origin of the right coronary artery with multiple coronary bicameral fistulae.

  Authors: Robert Brooks Wilson, U Joseph Schoepf, Yeong Shyan Lee, Gorka Bastarrika

  Journal of thoracic imaging. 04/2011; 27(2):W32-4.

  Cardiac computed tomography surpasses the limitations of conventional coronary angiography and transthoracic echocardiography in determining the origin, course, and extent of coronary arteryCardiac computed tomography surpasses the limitations of conventional coronary angiography and transthoracic echocardiography in determining the origin, course, and extent of coronary artery anomalies. This case report illustrates a rare combination of congenital coronary artery anomalies consisting of anomalous origin of the right coronary artery arising from the left sinus of Valsalva and multiple coronary bicameral fistulae.

• Intra-atrial course of the right coronary artery demonstrated at computed tomography coronary angiography.

  Authors: Yeong Shyan Lee, Gorka Bastarrika, U Joseph Schoepf

  Journal of thoracic imaging. 05/2010; 25(4):W115-7.

  Anomalies of the course of the right coronary artery are relatively rare but are diagnosed with increasing frequency by noninvasive coronary computed tomography angiography. Although most findings ofAnomalies of the course of the right coronary artery are relatively rare but are diagnosed with increasing frequency by noninvasive coronary computed tomography angiography. Although most findings of right coronary artery anomalies are inconsequential, there are certain variants that can result in catastrophic complications during surgical or interventional procedures if not recognized. We present a case of intra-atrial course of the right coronary artery noninvasively diagnosed by dual-source computed tomography coronary angiography.

• Relationship between coronary artery disease and epicardial adipose tissue quantification at cardiac CT: comparison between automatic volumetric measurement and manual bidimensional estimation.

  Authors: Gorka Bastarrika, Jordi Broncano, U Joseph Schoepf, Florian Schwarz, Yeong Shyan Lee, Joseph A Abro, Philip Costello, Peter L Zwerner

  Academic radiology. 04/2010; 17(6):727-34.

  The aim of this study was to compare the reproducibility of bidimensional and volumetric quantification of epicardial adipose tissue (EAT) on cardiac computed tomography (CT) and evaluate theirThe aim of this study was to compare the reproducibility of bidimensional and volumetric quantification of epicardial adipose tissue (EAT) on cardiac computed tomography (CT) and evaluate their relationship with the extent of coronary artery disease (CAD). Forty-five individuals underwent cardiac dual-source CT and conventional coronary angiography for suspicion of CAD. Nonenhanced images acquired to assess calcium score were used to quantify EAT. Coronary stenosis grading was performed on conventional coronary angiograms using Gensini scores. Two independent observers manually measured right ventricular EAT thickness at three different levels and in two different planes (four chamber and short axis) to obtain mean values. Additionally, EAT volume was automatically determined using a commercially available software tool. Conventional coronary angiography demonstrated nonstenotic coronary arteries in 22 subjects and significant coronary artery stenosis in 23. Significant correlations were observed between volumetric estimation of EAT and body mass index, coronary artery calcification, and Gensini score. On automatic volumetry, patients with significant coronary artery stenosis had significantly greater EAT volumes (154.58 +/- 58.91 mL) than those without significant CAD (120.94 +/- 81.85 mL) (P = .016). The manual bidimensional approach based on thickness measurements failed to show a significant difference between the two groups. Reproducibility and interobserver agreement for EAT quantification were higher when the automatic volumetric method was used (concordance-correlation coefficient, 0.96) compared to manual measurements (concordance-correlation coefficients, 0.37 for four-chamber EAT, 0.53 for short-axis EAT, and 0.58 for average EAT). For the quantification of EAT on cardiac CT, automated volumetry is more reproducible and correlates better with the extent of CAD than manual bidimensional measurements.

• CT of coronary artery disease.

  Authors: Gorka Bastarrika, Yeong Shyan Lee, Walter Huda, Balazs Ruzsics, Philip Costello, U Joseph Schoepf

  Radiology. 11/2009; 253(2):317-38.

  Technical innovation is rapidly improving the clinical utility of cardiac computed tomography (CT) and will increasingly address current technical limitations, especially the association of this testTechnical innovation is rapidly improving the clinical utility of cardiac computed tomography (CT) and will increasingly address current technical limitations, especially the association of this test with relatively high levels of radiation. Guidelines for appropriate indications are in place and are evolving, with an increasing evidence base to ensure the appropriate use of this modality. New technologies and new applications, such as myocardial perfusion imaging and dual-energy CT, are being explored and are widening the scope of coronary CT angiography from mere coronary artery assessment to the integrative analysis of cardiac morphology, function, perfusion, and viability. The scientific evaluation of coronary CT angiography has left the stage of feasibility testing and increasingly, evidence-based data are accumulating on outcomes, prognosis, and cost-effectiveness. In this review, these developments will be discussed in the context of current pivotal transitions in cardiovascular disease management and their potential influence on the current role and future fate of coronary CT angiography will be examined.

• Comparison of dual-energy computed tomography of the heart with single photon emission computed tomography for assessment of coronary artery stenosis and of the myocardial blood supply.

  Authors: Balazs Ruzsics, Florian Schwarz, U Joseph Schoepf, Yeong Shyan Lee, Gorka Bastarrika, Salvatore A Chiaramida, Philip Costello, Peter L Zwerner

  The American journal of cardiology. 09/2009; 104(3):318-26.

  To evaluate the performance of dual-energy computed tomography (CT) for integrative imaging of the coronary artery morphology and the myocardial blood supply, 36 patients (15 women, mean age 57 +/-To evaluate the performance of dual-energy computed tomography (CT) for integrative imaging of the coronary artery morphology and the myocardial blood supply, 36 patients (15 women, mean age 57 +/- 11 years) with equivocal or incongruous single photon emission CT (SPECT) results were investigated by a single-contrast medium-enhanced, retrospectively electrocardiographic-gated dual-energy CT (DECT) scan with simultaneous acquisition of high and low x-ray spectra. Thirteen patients subsequently underwent invasive coronary angiography (ICA). The DECT data were used to reconstruct anatomic coronary CT angiographic images and to map the myocardial iodine distribution within the left ventricular myocardium. Two independent observers analyzed all DECT studies for stenosis and myocardial iodine defects. A segmental comparison was performed between the stress/rest SPECT perfusion defects and DECT iodine defects and between the ICA and coronary CT angiographic findings for stenosis. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were estimated, along with the kappa statistics. Overall, DECT had 92% sensitivity and 93% specificity, with 93% accuracy for detecting any type of myocardial perfusion defect seen on SPECT. Contrast defects at DECT correctly identified 85 (96%) of 89 fixed and 60 (88%) of 68 reversible myocardial perfusion defects. The interobserver agreement was very good (weighted kappa = 0.87). Compared with ICA, coronary CT angiography had 90% sensitivity, 94% specificity, and 93% accuracy for the detection of >50% stenosis. In conclusion, our initial experience suggests that DECT, as a single examination, might be promising for the integrative analysis of the coronary artery morphology and the myocardial blood supply and is in good agreement with ICA and SPECT.

• Catheter-induced aorto-coronary artery dissection: Utility and appearance on CT coronary angiogram.

  Authors: Wee Thong Neo, Uei Pua, Yeong Shyan Lee

  International journal of cardiology. 04/2009;

  Aorto-coronary artery dissection (CCAD) is rare but potentially fatal complication of catheter coronary angiography. Management is dependent on the state of distal arterial flow and the extension ofAorto-coronary artery dissection (CCAD) is rare but potentially fatal complication of catheter coronary angiography. Management is dependent on the state of distal arterial flow and the extension of retrograde aortic dissection. This manuscript describes the use and appearance of CCAD on ECG-gated multi-detector CT coronary angiogram in the acute setting.

• Coronary CT Angiography: Applications.

  Authors: Gorka Bastarrika, Yeong Shyan Lee, Balazs Ruzsics, U Joseph Schoepf

  Radiologic clinics of North America. 02/2009; 47(1):91-107.

  With the widespread use of coronary CT angiography, new potential clinical indications are constantly being explored. Currently, 64-slice multidetector-row CT and dual-source CT are the benchmark forWith the widespread use of coronary CT angiography, new potential clinical indications are constantly being explored. Currently, 64-slice multidetector-row CT and dual-source CT are the benchmark for noninvasive coronary CT angiography; however, new technologies are already on the horizon. While significant obstacles still remain to be overcome, coronary CT angiography is closer than ever to fulfilling its promise of replacing invasive techniques in appropriate patient populations.

• Giant Kawasaki coronary artery aneurysm: cardiac imaging evolution.

  Authors: Yeong Shyan Lee, Christopher D Nielsen, U Joseph Schoepf

  European heart journal. 08/2008;