Markus Weininger

Publications of Markus Weininger

• 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.

• Subjective assessment of right ventricle enlargement from computed tomography pulmonary angiography images.

  Authors: Markus Weininger

  The international journal of cardiovascular imaging. 06/2011;

• Cardiothoracic CT angiography: current contrast medium delivery strategies.

  Authors: Markus Weininger, J Michael Barraza, Corey A Kemper, John F Kalafut, Philip Costello, U Joseph Schoepf

  AJR. American journal of roentgenology. 03/2011; 196(3):W260-72.

  OBJECTIVE: Over the last decade, rapid technologic evolution in CT has resulted in improved spatial and temporal resolution and acquisition speed, enabling cardiothoracic CT angiography to become aOBJECTIVE: Over the last decade, rapid technologic evolution in CT has resulted in improved spatial and temporal resolution and acquisition speed, enabling cardiothoracic CT angiography to become a viable and effective noninvasive alternative in the diagnostic algorithm. These new technologic advances have imposed new challenges for the optimization of contrast medium delivery and image acquisition strategies. CONCLUSION: Thorough understanding of contrast medium dynamics is essential for the design of effective acquisition and injection protocols. This article provides an overview of the fundamentals affecting contrast enhancement, emphasizing the modifications to contrast material delivery protocols required to optimize cardiothoracic CT angiography.

• Hemodynamic assessment of severe aortic stenosis: MRI evaluation of dynamic changes of vena contracta.

  Authors: Markus Weininger, Florian Sagmeister, Sebastian Herrmann, Volkmar Lange, U Joseph Schoepf, Matthias Beissert, Wolfram Voelker, Herbert Koestler, Dietbert Hahn, Frank Weidemann, Meinrad Beer

  Investigative radiology. 01/2011; 46(1):1-10.

  Direct magnetic resonance imaging (MRI) planimetry of the maximal systolic aortic valve area does not consider temporal variations of the opening area during the ejection period. We evaluated anDirect magnetic resonance imaging (MRI) planimetry of the maximal systolic aortic valve area does not consider temporal variations of the opening area during the ejection period. We evaluated an MRI-based methodology for the assessment of valvular dynamics in patients with severe aortic stenosis by measuring the systolic variability of the valvular blood stream, that is, the "vena contracta." With institutional review board approval, we examined 22 patients (13 male, 9 female; mean age, 68 ±10 years) with severe aortic stenosis using 1.5 T MRI and a standardized scanning protocol consisting of gradient-echo phase-contrast velocity imaging and steady-state free precession-cine MRI before and after valve replacement therapy. Temporal changes of the aortic valve area, represented by systolic variations of the area of poststenotic turbulent flow at its smallest convergence, that is, the proximal vena contracta, were determined by MRI and quantified by a calculated parameter of temporal valve dynamics (T). T was defined as the period which the aortic valve spent over its maximal opening area (>85%) during systole. MRI was also used to determine left ventricular hypertrophy before (LVMI) and its regression (LVMR) after valve replacement. Findings were compared with transthoracic echocardiography and cardiac catheterization. All patients had an echocardiographic effective orifice area, EOATTE, of <1.0 cm2. The comparison of T to LVMI and LVMR revealed significant correlations (LVMI: r = -0.62; P = 0.002; LVMR: r = 0.62; P = 0.002). Further significant correlations with aortic stenosis severity were observed in the comparison with manual planimetry, invasive measurements, and echocardiographic valve areas, as well as with pressure gradients. MRI can measure systolic variations of the aortic valve area. Quantitative parameters of the hemodynamic relevance of valve dynamics obtained by this method correlate with established parameters of aortic stenosis severity and LVMR.

• Integrative computed tomographic imaging of coronary artery disease.

  Authors: Markus Weininger, Matthias Renker, Garret W Rowe, Joseph A Abro, Philip Costello, U Joseph Schoepf

  Expert review of cardiovascular therapy. 01/2011; 9(1):27-43.

  Rapid technological evolution in multislice computed tomography (CT) over the last decade with improved spatial and temporal resolution has enabled cardiac CT to become a viable and effectiveRapid technological evolution in multislice computed tomography (CT) over the last decade with improved spatial and temporal resolution has enabled cardiac CT to become a viable and effective alternative in the diagnosis of coronary artery disease. Within recent years CT coronary angiography has demonstrated high sensitivity and specificity, and in particular a very high negative-predictive value, making it a valuable imaging modality for ruling out suspected coronary artery disease. In addition, CT angiography demonstrates accuracy in the detection and characterization of coronary plaques, and it has been reported to play an important role in predicting disease progression and cardiac events. The goal of this article is to provide an overview on the role and current clinical applications of cardiac CT in the evaluation of coronary artery disease. Emerging areas of cardiac CT, including dual-energy CT and CT myocardial perfusion are also discussed, as well as the limitations and future directions of cardiac CT.

• Cost-effectiveness of substituting dual-energy CT for SPECT in the assessment of myocardial perfusion for the workup of coronary artery disease.

  Authors: Mathias Meyer, John W Nance, U Joseph Schoepf, Antonio Moscariello, Markus Weininger, Garrett W Rowe, Balazs Ruzsics, Doo Kyoung Kang, Salvatore A Chiaramida, Stefan O Schoenberg, Christian Fink, Thomas Henzler

  European journal of radiology. 01/2011;

  PURPOSE: We compared cost-effectiveness and potential lifetime benefits of using dual-energy computed tomography (DECT) for myocardial perfusion assessment instead of single photon emission computedPURPOSE: We compared cost-effectiveness and potential lifetime benefits of using dual-energy computed tomography (DECT) for myocardial perfusion assessment instead of single photon emission computed tomography (SPECT) for the workup of coronary artery disease (CAD). MATERIALS AND METHODS: A decision and simulation model was developed to estimate cost and health effects of using DECT myocardial perfusion imaging instead of SPECT for identifying patients in need of invasive imaging and possible revascularization. The model was based on the performance indices of stress/rest DECT compared with stress/rest SPECT for detecting myocardial perfusion deficits in 50 patients (mean age 61±10 years) with CAD. Stress/rest perfusion and delayed enhancement cardiac MRI served as reference standard. For DECT a reimbursement of US$1700 was assumed but costs of cardiac MRI were not included in the model. All other actual healthcare costs in these patients were derived from MUSC's hospital billing system. RESULTS: Compared with cardiac MRI, DECT (versus SPECT) had 90% (85%) sensitivity and 71% (58%) specificity for identifying patients with obstructive CAD. Compared with the no imaging and no treatment strategy, routine SPECT gained 13.49 quality-adjusted life-years (QALYs) with an incremental cost-effectiveness ratio (ICER) of US$3557 (in 2010) per QALY. In comparison, DECT ICER was lower (US$3.191 per QALY, p=0.0002) and an additional 0.64 QALYs was obtained (total of 14.13 QALYs) if compared with the SPECT strategy as well as the no imaging and no treatment strategy. CONCLUSION: Using DECT as the first-line imaging test for myocardial perfusion for the workup of patients with CAD has the potential to provide gains in QALYs, while lowering costs if compared to routine myocardial perfusion SPECT.

• Adenosine-stress dynamic real-time myocardial perfusion CT and adenosine-stress first-pass dual-energy myocardial perfusion CT for the assessment of acute chest pain: Initial results.

  Authors: Markus Weininger, U Joseph Schoepf, Ashok Ramachandra, Christian Fink, Garrett W Rowe, Philip Costello, Thomas Henzler

  European journal of radiology. 12/2010;

  PURPOSE: Recent innovations in CT enable the evolution from mere morphologic imaging to dynamic and functional testing. We describe our initial experience performing myocardial stress perfusion CT inPURPOSE: Recent innovations in CT enable the evolution from mere morphologic imaging to dynamic and functional testing. We describe our initial experience performing myocardial stress perfusion CT in a clinical population with acute chest pain. METHODS AND MATERIALS: Myocardial stress perfusion CT was performed on twenty consecutive patients (15 men, 5 women; mean age 65±8 years) who presented with acute chest pain and were clinically referred for stress/rest SPECT and cardiac MRI. Prior to CT each patient was randomly assigned either to Group A or to Group B in a consecutive order (10 patients per group). Group A underwent adenosine-stress dynamic real-time myocardial perfusion CT using a novel "shuttle" mode on a 2nd generation dual-source CT. Group B underwent adenosine-stress first-pass dual-energy myocardial perfusion CT using the same CT scanner in dual-energy mode. Two experienced observers visually analyzed all CT perfusion studies. CT findings were compared with MRI and SPECT. RESULTS: In Group A 149/170 myocardial segments (88%) could be evaluated. Real-time perfusion CT (versus SPECT) had 86% (84%) sensitivity, 98% (92%) specificity, 94% (88%) positive predictive value, and 96% (92%) negative predictive value in comparison with perfusion MRI for the detection of myocardial perfusion defects. In Group B all myocardial segments were available for analysis. Compared with MRI, dual-energy myocardial perfusion CT (versus SPECT) had 93% (94%) sensitivity, 99% (98%) specificity, 92% (88%) positive predictive value, and 96% (94%) negative predictive value for detecting hypoperfused myocardial segments. CONCLUSION: Our results suggest the clinical feasibility of myocardial perfusion CT imaging in patients with acute chest pain. Compared to MRI and SPECT both, dynamic real-time perfusion CT and first-pass dual-energy perfusion CT showed good agreement for the detection of myocardial perfusion defects.

• Emergency computed tomography for aortic valve vegetation mimicking disruption.

  Authors: Markus Weininger, Cagatay Yildirim, Christian Ritter, Rainer Leyh, Dietbert Hahn, Matthias Beissert

  Asian cardiovascular & thoracic annals. 02/2010; 18(1):68-70.

  A 47-year-old man presented with symptoms typical of infective endocarditis and history of streptococcal meningitis 8 months previously. Echocardiography showed a large aortic valve vegetation thatA 47-year-old man presented with symptoms typical of infective endocarditis and history of streptococcal meningitis 8 months previously. Echocardiography showed a large aortic valve vegetation that was interpreted as disruption of the noncoronary cusp. This was ruled out by 64-slice cardiac computed tomography. Valve replacement was performed successfully.

• Large pulmonary hernia following thoracotomy.

  Authors: Christian O Ritter, Markus Weininger, Dietbert Hahn, Matthias Beissert

  Asian cardiovascular & thoracic annals. 10/2009; 17(5):535-6.

• Quantitative contrast-enhanced perfusion measurements of the human lung using the prebolus approach.

  Authors: Markus Oechsner, Matti Mühlhäusler, Christian O Ritter, Markus Weininger, Matthias Beissert, Peter M Jakob, Meinrad Beer, Dietbert Hahn, Herbert Köstler

  Journal of magnetic resonance imaging : JMRI. 07/2009; 30(1):104-111.

  PURPOSE: To investigate dynamic contrast-enhanced MRI (DCE-MRI) for quantification of pulmonary blood flow (PBF) and blood volume (PBV) using the prebolus approach and to compare the results to thePURPOSE: To investigate dynamic contrast-enhanced MRI (DCE-MRI) for quantification of pulmonary blood flow (PBF) and blood volume (PBV) using the prebolus approach and to compare the results to the global lung perfusion (GLP). MATERIALS AND METHODS: Eleven volunteers were examined by applying different contrast agent doses (0.5, 1.0, 2.0, and 3.0 mL gadolinium diethylene triamine pentaacetic acid [Gd-DTPA]), using a saturation-recovery (SR) true fast imaging with steady precession (TrueFISP) sequence. PBF and PBV were determined for single bolus and prebolus. Region of interest (ROI) evaluation was performed and parameter maps were calculated. Additionally, cardiac output (CO) and lung volume were determined and GLP was calculated as a contrast agent-independent reference value. RESULTS: The prebolus results showed good agreement with low-dose single-bolus and GLP: PBF (mean +/- SD in units of mL/minute/100 mL) = single bolus 190 +/- 73 (0.5-mL dose) and 193 +/- 63 (1.0-mL dose); prebolus 192 +/- 70 (1.0-2.0-mL dose) and 165 +/- 52 (1.0-3.0-mL dose); GLP (mL/minute/100 mL) = 187 +/- 34. Higher single-bolus resulted in overestimated values due to arterial input function (AIF) saturation. CONCLUSION: The prebolus approach enables independent determination of appropriate doses for AIF and tissue signal. Using this technique, the signal-to-noise ratio (SNR) from lung parenchyma can be increased, resulting in improved PBF and PBV quantification, which is especially useful for the generation of parameter maps. J. Magn. Reson. Imaging 2009;30:104-111. (c) 2009 Wiley-Liss, Inc.

• Heartmate II Implantation with Right Coronary Bypass Grafting in Ischemic Cardiomyopathy with "Fixed" Pulmonary Hypertension: Treatment Strategy to Protect Right Ventricular Function.

  Authors: Sebastian-Patrick Sommer, Armin Gorski, Ivan Aleksic, Cagatay Yildirim, Christoph Schimmer, Matthias Beissert, Markus Weininger, Rainer G Leyh

  Journal of cardiac surgery. 07/2009;

  Abstract A 49-year-old male patient suffering from end-stage ischemic cardiomyopathy with a left ventricular ejection fraction below 15% was presented to redo coronary artery bypass grafting (CABG).Abstract A 49-year-old male patient suffering from end-stage ischemic cardiomyopathy with a left ventricular ejection fraction below 15% was presented to redo coronary artery bypass grafting (CABG). Coronary angiogram demonstrated an occluded left anterior descending artery and occluded right coronary artery, perfused retrogradely from the circumflex artery. Since positron emission tomography did not demonstrate viable left ventricular myocardium except for the basis of the left ventricle, CABG was considered futile. Cardiac transplantation was contra-indicated due to pharmacologically unresponsive pulmonary artery hypertension. The patient successfully underwent left ventricular assist device implantation in combination with right coronary artery revascularization. The article reflects the regimen of right ventricular preservation in this patient. (J Card Surg ****;**:**-**).

• Cardiac computed tomography of aortocoronary bypass in type a aortic dissection.

  Authors: Markus Weininger, Christian O Ritter, Dietbert Hahn, Matthias Beissert

  Asian cardiovascular & thoracic annals. 02/2008; 16(1):86-7.

• Whole-body MRI of multiple myeloma: Comparison of different MRI sequences in assessment of different growth patterns.

  Authors: Markus Weininger, Brigitte Lauterbach, Stefan Knop, Thomas Pabst, Werner Kenn, Dietbert Hahn, Matthias Beissert

  European journal of radiology. 01/2008;

  PURPOSE: To determine sensitivity, specificity and inter-observer variability of different whole-body MRI (WB-MRI) sequences in patients with multiple myeloma (MM). METHODS AND MATERIALS: WB-MRIPURPOSE: To determine sensitivity, specificity and inter-observer variability of different whole-body MRI (WB-MRI) sequences in patients with multiple myeloma (MM). METHODS AND MATERIALS: WB-MRI using a 1.5T MRI scanner was performed in 23 consecutive patients (13 males, 10 females; mean age 63+/-12 years) with histologically proven MM. All patients were clinically classified according to infiltration (low-grade, n=7; intermediate-grade, n=7; high-grade, n=9) and to the staging system of Durie and Salmon PLUS (stage I, n=12; stage II, n=4; stage III, n=7). The control group consisted of 36 individuals without malignancy (25 males, 11 females; mean age 57+/-13 years). Two observers independently evaluated the following WB-MRI sequences: T1w-TSE (T1), T2w-TIRM (T2), and the combination of both sequences, including a contrast-enhanced T1w-TSE with fat-saturation (T1+/-CE/T2). They had to determine growth patterns (focal and/or diffuse) and the MRI sequence that provided the highest confidence level in depicting the MM lesions. Results were calculated on a per-patient basis. RESULTS: Visual detection of MM was as follows: T1, 65% (sensitivity)/85% (specificity); T2, 76%/81%; T1+/-CE/T2, 67%/88%. Inter-observer variability was as follows: T1, 0.3; T2, 0.55; T1+/-CE/T2, 0.55. Sensitivity improved depending on infiltration grade (T1: 1=60%; 2=36%; 3=83%; T2: 1=70%; 2=71%; 3=89%; T1+/-CE/T2: 1=50%; 2=50%; 3=89%) and clinical stage (T1: 1=58%; 2=63%; 3=79%; T2: 1=58%; 2=88%; 3=100%; T1+/-CE/T2: 1=50%; 2=63%; 3=100%). T2w-TIRM sequences achieved the best reliability in depicting the MM lesions (65% in the mean of both readers). CONCLUSIONS: T2w-TIRM sequences achieved the highest level of sensitivity and best reliability, and thus might be valuable for initial assessment of MM. For an exact staging and grading the examination protocol should encompass unenhanced and enhanced T1w-MRI sequences, in addition to T2w-TIRM.

• Influence of retrospective sorting on image quality in respiratory correlated computed tomography.

  Authors: Matthias Guckenberger, Markus Weininger, Juergen Wilbert, Anne Richter, Kurt Baier, Thomas Krieger, Buelent Polat, Michael Flentje

  Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 12/2007; 85(2):223-31.

  PURPOSE: To evaluate the influence of retrospective sorting on image quality in four-dimensional respiratory correlated CT. MATERIALS AND METHODS: Twelve patients with intrapulmonary tumors werePURPOSE: To evaluate the influence of retrospective sorting on image quality in four-dimensional respiratory correlated CT. MATERIALS AND METHODS: Twelve patients with intrapulmonary tumors were examined using a 24-slice CT-scanner in helical mode. Images were reconstructed after retrospective sorting based on five algorithms: amplitude-based sorting with definition of peak-exhalation and peak-inhalation separately/locally for all breathing cycles (LAS) and globally for the time of image acquisition (GAS). Drifts of the breathing signal were corrected in dc-GAS. In phase-based (PS) and cycle-based (CS) algorithm the projections were sorted relative to time. Motion artifacts were scored by a radiologist. The tumor volumes were measured using automatic image segmentation. RESULTS: Averaged over all breathing phases, LAS and PS achieved significantly improved image quality and lowest tumor volume variability compared to GAS, dc-GAS and CS. Imaging redundancy of 5s was not sufficient for GAS and dc-GAS: missing corresponding amplitude positions in one or several breathing cycles resulted in incomplete reconstruction of peak-ventilation images in 11/12 and 10/12 patients with GAS and dc-GAS, respectively. Limiting the analysis to mid-ventilation phases showed GAS and dc-GAS as the most reliable algorithms. CONCLUSIONS: LAS and PS are suggested as a compromise between image quality and radiation dose.

• Multi-slice cardiac computed tomography reveals anomalous origin of the right coronary artery between the great arteries.

  Authors: Markus Weininger, Andreas Bonz, Meinrad Beer, Dietbert Hahn, Matthias Beissert

  International journal of cardiology. 08/2007; 119(3):e77-8.

  We report a case of a 72-year-old man whose multi-slice cardiac computed tomography revealed an anomalous origin of the right coronary artery between the great arteries.

• Complete remission of liver metastasis of pancreatic cancer under vaccination with a HLA-A2 restricted peptide derived from the universal tumor antigen survivin.

  Authors: Marion Wobser, Petra Keikavoussi, Volker Kunzmann, Markus Weininger, Mads H Andersen, Juergen C Becker

  Cancer immunology, immunotherapy : CII. 11/2006; 55(10):1294-8.

  PURPOSE: As prognosis of advanced pancreatic cancer remains gloomy, novel therapeutic modalities have to be developed. Immunotherapy, which targets tumor-associated antigens of tumor cells or tumorPURPOSE: As prognosis of advanced pancreatic cancer remains gloomy, novel therapeutic modalities have to be developed. Immunotherapy, which targets tumor-associated antigens of tumor cells or tumor stroma, is currently under investigation. As survivin is expressed by neoplastic and tumor endothelial cells, but rarely by normal cells, this antigen appears as an intriguing target molecule. METHODS: A 72-year old patient, suffering from pancreatic cancer refractory to gemcitabine therapy, received the survivin-based peptide vaccinations consisting of 100 mug of a modified HLA-A2 restricted survivin(96-104) epitope in Montanide(R). Each visit the patient was assessed for adverse events, quality of life and immunological response. Immuno-monitoring was performed by IFN-gamma-ELISPOT analysis of peripheral blood lymphocytes. Clinical outcome was evaluated by repetitive computed tomography. RESULTS: Under vaccination with survivin peptides the patient initially underwent partial remission of liver metastasis which proceeded after 6 months into a complete remission with a duration of 8 months. Immunological monitoring revealed strong vaccine-induced immune-reactivity against survivin. Unfortunately, after the patient was weaned from vaccination in state of no evidence of disease, he developed recurrent disease. CONCLUSION: T-cell responses against survivin-expressing cells of the tumor itself and tumor endothelium should impact tumor growth and metastasis. The presented patient with pancreatic cancer is the first example of a successful application of a survivin-based vaccination in the clinical setting. An ongoing phase I/II trial with HLA-A1, -A2 and -B35 restricted survivin peptides for patients with advanced cancer will provide further information towards this notion.

• Assessment of a left coronary artery aneurysm with 64-channel multi-slice cardiac computed tomography.

  Authors: Markus Weininger, Malte Meesmann, Dietbert Hahn, Matthias Beissert

  European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. 09/2006; 30(2):381-2.