Hans-Christoph Becker

Publications of Hans-Christoph Becker

• Radiation exposure and image quality of normal computed tomography brain images acquired with automated and organ-based tube current modulation multiband filtering and iterative reconstruction.

  Authors: Hans-Christoph Becker, Dominik Augart, Martina Karpitschka, Stefan Ulzheimer, Fabian Bamberg, Dominik Morhard, Klement Neumaier, Anno Graser, Thorsten Johnson, Maximilian Reiser

  Investigative radiology. 03/2012; 47(3):202-7.

  : We sought to determine whether radiation dose can be reduced and image quality improved in computed tomography (CT) images of the brain that were acquired with automated exposure control (AEC),: We sought to determine whether radiation dose can be reduced and image quality improved in computed tomography (CT) images of the brain that were acquired with automated exposure control (AEC), organ-based tube current modulation (TCM), multiband filtration (MBF), and iterative reconstruction in image space (IRIS). : An Alderson-Rando-phantom, equipped with thermoluminescent dosimeters, was used to determine the radiation exposure of organs within the head and neck by different CT brain scan modes. We measured the noise and signal-to-noise ratios and subjectively graded quality criteria in different territories of the brain in spiral CT images of 150 patients. We also derived the radiation exposure from the patient protocols. : In the phantom, AEC and TCM reduced the radiation exposure of the lenses, cerebrum, cerebellum, and thyroid gland by 41.9%, 34.5%, 30.5%, and 34.9%, respectively. Brain CT scans from patients investigated with AEC, TCM, MBF, and IRIS were found to have significantly better image quality than with conventional filtered back projection. In addition, the CT dose index and dose-length product were significantly lower with AEC, TCM, MBF, and IRIS by 24.1% and 20.2%, respectively. : The combination of AEC, TCM, MBF, and IRIS improves image quality while radiation exposure can be reduced, particularly in dose-sensitive organs, such as the lenses and thyroid gland.

• Cardiac CT for the assessment of chest pain: Imaging techniques and clinical results.

  Authors: Hans-Christoph Becker, Thorsten Johnson

  European journal of radiology. 07/2011;

  Immediate and efficient risk stratification and management of patients with acute chest pain in the emergency department is challenging. Traditional management of these patients includes serial ECG,Immediate and efficient risk stratification and management of patients with acute chest pain in the emergency department is challenging. Traditional management of these patients includes serial ECG, laboratory tests and further on radionuclide perfusion imaging or ECG treadmill testing. Due to the advances of multi-detector CT technology, dedicated coronary CT angiography provides the potential to rapidly and reliably diagnose or exclude acute coronary artery disease. Life-threatening causes of chest pain, such as aortic dissection and pulmonary embolism can simultaneously be assessed with a single scan, sometimes referred to as "triple rule out" scan. With appropriate patient selection, cardiac CT can accurately diagnose heart disease or other sources of chest pain, markedly decrease health care costs, and reliably predict clinical outcomes. This article reviews imaging techniques and clinical results for CT been used to evaluate patients with chest pain entering the emergency department.

• Hyperdense basilar artery sign-a reliable sign of basilar artery occlusion.

  Authors: Lara Connell, Inga Katharina Koerte, Ruediger Paul Laubender, Dominik Morhard, Jennifer Linn, Hans Christoph Becker, Maximilian Reiser, Hartmut Brueckmann, Birgit Ertl-Wagner

  Neuroradiology. 05/2011;

  INTRODUCTION: We aimed to investigate the value of the hyperdense basilar artery (HBA) sign and of basilar artery (BA) attenuation measurements as predictors of basilar artery occlusion (BAO) onINTRODUCTION: We aimed to investigate the value of the hyperdense basilar artery (HBA) sign and of basilar artery (BA) attenuation measurements as predictors of basilar artery occlusion (BAO) on nonenhanced cranial CT (NECT). METHODS: Forty-one consecutive patients with proven BAO in CT angiography, who had undergone NECT for initial evaluation (30 males, 11 females) were retrospectively included. Another 41 age-matched patients without BAO were included as a control group. The NECT scans of both groups were assessed by three independent blinded readers (staff, fellow, and resident) in a randomized reading order using a standardized semiquantitative questionnaire. Visual BA hyperdensity, including the presence of HBA sign (hyperdensity scores of 4 and 5/5), was assessed, quantitative BA attenuation was measured in a region of interest (ROI), and diagnosis of BAO was made before and after ROI measurements. For statistical analysis, multivariate mixed effects models, likelihood ratio tests, and receiver operating characteristics techniques were applied. RESULTS: HBA sign had a relatively low sensitivity (60.98-65.85%), specificity (70.73-90.24%), and accuracy (65.85-75.61%) for the presence/absence of BAO on NECT. Optimal cut-off points were 40-42 HU (sensitivity, 68.29-78.05%; specificity, 75.61-82.93%; accuracy, 74.39-80.49%). CONCLUSION: In basilar artery occlusion, quantitative measurement of BA attenuation can slightly improve the diagnostic predictiveness of NECT. However, even with optimal cut-off values, the sensitivity is too low to serve as the sole diagnostic decision-making tool.

• Practical strategies for low radiation dose cardiac computed tomography.

  Authors: Thomas Henzler, Michael Hanley, Elisabeth Arnoldi, Gorka Bastarrika, U Joseph Schoepf, Hans-Christoph Becker

  Journal of thoracic imaging. 08/2010; 25(3):213-20.

  Concerns have been raised regarding the increasing radiation exposure associated with cardiac computed tomography (CT). Traditional cardiac CT imaging techniques comprise simultaneous recording ofConcerns have been raised regarding the increasing radiation exposure associated with cardiac computed tomography (CT). Traditional cardiac CT imaging techniques comprise simultaneous recording of the electrocardiogram signal combined with continuous slow-pitch spiral/helical scan acquisition with a relatively high incident radiation dose. Because of the increasing number of cardiac CT studies and further anticipated growth, the contribution of cardiac CT to radiation exposure of the population is not negligible. With growing radiation dose awareness, a variety of strategies have been developed aimed at improving the dose efficiency of electrocardiogram-synchronized cardiac CT acquisition techniques. Recent innovations have demonstrated that the radiation dose at cardiac CT can be substantially reduced without detrimental effects on diagnostic image quality. This study reviews currently available strategies for successfully reducing radiation dose in cardiac CT.

• Determination of glomerular filtration rate using dynamic CT-angiography: simultaneous acquisition of morphological and functional information.

  Authors: Andreas Helck, Wieland H Sommer, Ernst Klotz, Matthias Wessely, Steven Pieter Sourbron, Konstantin Nikolaou, Dirk A Clevert, Mike Notohamiprodjo, Wolf D Illner, Maximilian Reiser, Hans-Christoph Becker

  Investigative radiology. 07/2010; 45(7):387-92.

  To determine the feasibility of a dynamic CT angiography-protocol in regard to simultaneous assessment of morphology and function. Fourteen patients with renal graft dysfunction received a dynamicTo determine the feasibility of a dynamic CT angiography-protocol in regard to simultaneous assessment of morphology and function. Fourteen patients with renal graft dysfunction received a dynamic computed tomography angiography (CTA) using a 128-slice CT-scanner with continuous bi-directional table movement, allowing to cover a scan range of 18 cm within 1.75 seconds. Twelve scans of the entire kidney were acquired every 3.5 seconds with the aim to simultaneously obtain CTA and renal function data. The glomerular filtration rate (GFR) was calculated by a modified Patlak method and compared with creatinine-based formulas (MDRD 4 and endogenous creatinine clearance), that served as reference standard. GFR obtained from dynamic CTA correlates well with the GFR derived by creatinine-based formulas with a correlation coefficient of r = 0.8986; P < 0.0001. The average absolute deviation was 8.1 mL/min. The mean amount of contrast medium required was 35 mL. The average effective dose was 13.8 mSv. Dynamic CTA offers the possibility to determine the GFR and thus facilitates simultaneous assessment of morphology and function. Additionally, our dynamic CTA-protocol helps to significantly reduce the amount of contrast medium, which is beneficial for patients with impaired renal function.

• Value of 11C-choline PET and PET/CT in patients with suspected prostate cancer.

  Authors: Bernhard Scher, Michael Seitz, Wolfram Albinger, Reinhold Tiling, Michael Scherr, Hans-Christoph Becker, Michael Souvatzogluou, Franz-Josef Gildehaus, Hans-Jürgen Wester, Stefan Dresel

  European journal of nuclear medicine and molecular imaging. 02/2007; 34(1):45-53.

  PURPOSE: The value and limitations of (11)C-choline PET and PET/CT for the detection of prostate cancer remain controversial. The aim of this study was to investigate the diagnostic efficacy ofPURPOSE: The value and limitations of (11)C-choline PET and PET/CT for the detection of prostate cancer remain controversial. The aim of this study was to investigate the diagnostic efficacy of (11)C-choline PET and PET/CT in a large group of patients with suspected prostate cancer. METHODS: Fifty-eight patients with clinical suspicion of prostate cancer underwent (11)C-choline PET (25/58, Siemens ECAT Exact HR+) or PET/CT (33/58, Philips Gemini) scanning. On average, 500 MBq of (11)C-choline was administered intravenously. Studies were interpreted by raters blinded to clinical information and other diagnostic procedures. Qualitative image analysis as well as semiquantitative SUV measurement was carried out. The reference standard was histopathological examination of resection specimens or biopsy. RESULTS: Prevalence of prostate cancer in this selected patient population was 63.8% (37/58). (11)C-choline PET and PET/CT showed a sensitivity of 86.5% (32/37) and a specificity of 61.9% (13/21) in the detection of the primary malignancy. With regard to metastatic spread, PET showed a per-patient sensitivity of 81.8% (9/11) and produced no false positive findings. CONCLUSION: Based on our findings, differentiation between benign prostatic changes, such as benign prostatic hyperplasia or prostatitis, and prostate cancer is feasible in the majority of cases when image interpretation is primarily based on qualitative characteristics. SUV(max) may serve as guidance. False positive findings may occur due to an overlap of (11)C-choline uptake between benign and malignant processes. By providing functional information regarding both the primary malignancy and its metastases, (11)C-choline PET may prove to be a useful method for staging prostate cancer.