Thorsten R. C. Johnson, M.D.

The aim of the study was to assess the performance and diagnostic value of a dual energy CT approach to reduce metal artefacts in subjects with metallic implants. Read more

This article is part of the seven-article series on “Dual Energy CT – Scientific Evidence and Clinical Application” and gives an outlook on Dual Energy CT in clinical CT imaging. Read more

This article is part of the seven-article series on “Dual Energy CT – Scientific Evidence and Clinical Application”. The article gives an overview about protocols that have been implemented as standard settings in clinical routine and replaced single energy protocols for many applications. Read more

This article is part of the seven-article series on “Dual Energy CT – Scientific Evidence and Clinical Application”. It covers Dual Energy applications of the extremities including gout and metal artifact reduction. Read more

This article is part of the seven-article series on “Dual Energy CT – Scientific Evidence and Clinical Application”. T. Johnson talks about DE applications in abdominal imaging including aorta and plaque imaging. Read more

This article is part of the seven-article series on “Dual Energy CT – Scientific Evidence and Clinical Application”. T. Johnson talks about DE applications in thoracic imaging comprising lung perfusion, lung ventilation, pulmonary nodules, and myocardial perfusion. Read more

This article is part of the seven-article series on “Dual Energy CT – Scientific Evidence and Clinical Application”. It covers Dual Energy applications of head and neck. Read more

This article is part of the seven-article series on “Dual Energy CT – Scientific Evidence and Clinical Application”. It covers the practical technical aspects of Dual Energy: scan protocols and postprocessing. Read more

In this book, physicists and specialists from different CT manufacturers provide an insight into the technological basis of, and the different approaches to, dual-energy CT. Read more

The high-pitch dual spiral technique requires only about onefifth of the dose of conventional ECG gated triple-rule-out protocols, thus matching that of a standard nongated chest scan. Read more

To evaluate the feasibility of dual-energy CT (DECT) ventilation imaging in combination with DE perfusion mapping for a comprehensive assessment of the lung. Read more

New generation DSCT scanners offer different x-ray spectra for Dual Energy imaging. Yet, an objective, manufacturer independent verification of the dose required for the different spectral combinations is lacking. Read more

The objective of this study was to evaluate the feasibility and efficiency of this technique by comparing maximum intensity projections (MIP) created with different bone removal techniques. Read more

Massive central and segmental pulmonary embolism. Read more

See pictures of a normal lung perfusion assessed with Flash scanning. Read more

Minimal subpleural loss of perfusion due to a sub-subsegmental pulmonary embolism that can´t be distinguished with angiography. Read more

Purpose of this study was to determine the diagnostic value of dual energy CT in the assessment of pulmonary perfusion with reference to pulmonary perfusion scintigraphy. Read more

Case history: Unclear recurrent angina; Diagnosis: Coronary artery disease can be excluded. Read more

Case history: Unclear chest pain. Diagnosis: Exclusion of coronary artery disease. Read more

Case history: Unclear chest pain. Diagnosis: Exclusion of coronary artery disease. Read more

Case history: Long term artificial respiration with insufficient oxygenization. Diagnosis: Color-coded overlay shows xenon distribution. The lack of ventilation in the posteromedial segment of the right low lobe becomes visible. Read more

Case history: 13 year old female patient. Resuscitation after asystole for unclear cause diagnosis exclusion of coronary anomaly. Diagnosis: A coronary artery anomaly is ruled out. Read more

Case history: Exclusion of coronary artery disease prior to flecainid therapy. Diagnosis: Coronary artery disease can be excluded. Read more

Case history: Stroke; Diagnosis: The cranial arteries and veins are patent. Read more

Case History: Acute chest pain – Triple rule out; Diagnosis: Subsegmental pulmonary embolism. Read more

Objective: In supraaortic vessels, bone subtracted maximum intensity projections make the evaluation of computed tomographic angiography (CTA) datasets easier and faster. Dual energy CT can be used for bone removal without user interaction. The purpose of this study was to compare the results of conventional and dual energy-based bone removal. Materials … Read more

This fourth article of our Dual Energy series gives an overview of the most important clinical applications of Dual Energy, including color coding of contrast material, perfusion imaging, angiography, and differentiation of renal stones and tendons/ligaments. Read more

This third article of our Dual Energy-series focuses on the technical implementation of Dual Energy technology. For Dual Energy scanning, the tube potentials are mostly set to 140 and 80 kVp to obtain the largest spectral difference. Weighted average images are calculated by the image reconstruction system to resemble normal 120 … Read more

This second article of our new Dual Energy series describes the physics Dual Energy technology. Read more

This first article of our new Dual Energy series introduces you to Dual Energy. Dual Source CT had initially been developed to increase the temporal resolution of CT for cardiac imaging. By now, Dual Energy CT is ready for routine clinical use. Read more

The purpose of this study was to assess the image quality of coronary CT angiograms with coronary angiography, using a dual-source CT scanner (DSCT), comparing systolic and diastolic reconstruction techniques. Additionally, we sought to evaluate the diagnostic accuracy of DSCT with coronary angiography as the standard of reference. Read more

This article represents an abstract from the original case report. To read the whole article, please visit Circulation. 2009 Mar 3;119(8):1158-60. History A 46-year-old female patient presented at the emergency department with hemoptysis of unknown cause. Past medical history was significant for pulmonary hypertension with Eisenmenger syndrome due to … Read more

The following question has been sent by Antonio Maestro: Use of Flash and DE to replace SPECT in detection of ischemia tests? Hi, i am doing a research to assess the clinical and patient workflow results of using a DSCT Definition Flash for the Chest Pain Unit patients. It seems clear to me … Read more

Judy Oltman, USA, has sent the following question: Contrast blending for right ventricular function: We do a fair amount of pediatric congenital hearts and need to assess right ventricular function. Are there any particular blends of contrast administration that works well with attemping to get appropriate contrast fill without too much contamination? Thorsten … Read more

Scott Schonhover, technologist, USA, has sent the following question: DE Runoffs: Is anyone doing these either as research or in a clinical setting? If so is there a protocol for scanning and/or injection? I undertand that certain body habitus patients would exceed scan FOV’s. One of our doc’s is contemplating a research study on … Read more

Abrar Hayat, Kuwait, has sent the following question: dose reduction in DSCT compared to 64-MDCT: Other venders claim that they have upgraded their 64-MDCT with new applications so that the dose is reduced by 50 % compared to their regular 64-MDCT! how does the DSCT compare to those? Am I going to … Read more

Hugo Martinez, Mexico, has sent the following question: Hello all my questions is about osteosyntesis material do you have any information about DE can reduce the artifact that causes the osteosyntesis material for example in wrist or knee. Thorsten R.C. Johnson, M.D., University Hospitals Munich: Theoretically it would be possible to reduce metal … Read more

Please, click on the title to see the protocol. Read more

The following question has been sent by  Minh Truong: Please, give me a advise, How to compare between CT perfusion and MR perfusion, which one is better than? thank you and best regards Thorsten R.C. Johnson, M.D., University Hospitals Grosshadern, Munich: Both MR and CT pulmonary perfusion imaging are currently still being evaluated scientifically … Read more

Spiral dual energy CT angiography offers new opportunities for the assessing the relevance of pulmonary emboli. In an initial study at the University of Munich, we examined 24 patients with suspected pulmonary embolism. Exams were performed with a single acquisition, spiral dual energy CT angiography protocol on a SOMATOM Definition. Voxels … Read more

Jul 4, 2008 to Jul 5, 2008. The ability to simultaneously operate two X-ray sources at different energy levels – and therefore differentiate materials like fat, soft tissue, and contrast agent on the basis of their unique energy-dependent attenuation profiles – is opening the door to a host of clinically useful applications. This course is designed to … Read more

History A 72-year-old female patient suffering from severe dyspnea is referred for pulmonary CT angiography to rule out pulmonary embolism. Question CT angiography is performed to rule out pulmonary embolism, right heart dilatation or pulmonary hypertension. Diagnosis/Differential diagnosis Apart from acute pulmonary embolism, differential diagnoses include primary right heart failure, secondary pulmonary hypertension, congestive heart … Read more

Case History 67-year old with severe dyspnea and positive D-dimer test is referred for CT angiography to confirm or to rule out pulmonary embolism. Question The primary clinical concern … Read more

Please, click on the title to see the protocol. Read more

CT angiography has emerged as the diagnostic standard for detecting pulmonary embolism. It has been shown that pulmonary emboli can be detected with high reliability even at segmental and subsegmental levels. Recent studies have shown the sensitivity of CTA to be 90 – 100 % and the specificity to be … Read more

The following question has been sent by Dr. Zhaoyane, Jinling Hospital Nanjing, China: Is the intensity of the color coding related to that of iodine in lung perfusion? Thanks! Thorsten R.C. Johnson M.D., University Hospitals Grosshadern, Munich: Of course, the intensity of the color is to represent the content of iodine in the … Read more

The following question has been sent by Rusli Muljadi MD, Indonesia: How to make good picture in arrhythmia patient: We have performed cardiac CT of 3 patient with arrhythmia by Dual source CT. The pictures show motion artifact/ stepping. The type of of arrhythmia are ventricular extrasystole of 1 patient, supraventricular … Read more

The following question has been sent by Dr. Zhouyisheng, China: Could you tell me how to scan and postprocess: Could you tell me the scan protocol on dual-energy (lung perfusion) and how to postprocess if you use MINinum -960 ,MAX -600 (siemens default). You can get one result then you use … Read more

Case history A 50-year-old male with known coronary artery disease presents with acute chest pain two weeks after stenting of the left anterior descending coronary artery. Question Is the stent occluded? Is there a restenosis or another coronary artery stenosis? Is there another cause of chest pain? Diagnosis / Differential diagnosis The differential diagnoses in … Read more

Case history A 65-year-old female presents with unclear chest pain and dyspnea. The symptoms are nonspecific. Initial troponin test and ECG are normal. Question Is there an acute cardiovascular condition requiring immediate intervention? Is there evidence of the cause of chest pain? Diagnosis / Differential diagnosis The most important and potentially lifethreatening causes of chest … Read more

In recent studies at Munich University, the combined Dual Source CT protocol for chest pain assessment showed a high sensitivity for the cause of chest pain. Due to its robust image quality even in high heart rates DSCT greatly improves diagnostic accuracy. In cases of acute chest pain, the initial focus … Read more

The Dual Source CT protocol for chest pain assessment proved to be a helpful tool offering a fast diagnostic workup and patient triage. The heart rate insensitivity of DSCT further increases the diagnostic accuracy of the method by improving coronary artery assessment in acutely ill patients. The initial symptoms of the … Read more

The aim of this study was to assess the feasibility of a differentiation of iodine from other materials and of different body tissues using dual energy CT. Ten patients were scanned on a SOMATOM Definition Dual Source CT (DSCT; Siemens, Forchheim, Germany) system in dual energy mode at tube voltages … Read more

Abstract Purpose: The aim of this study was to evaluate the diagnostic accuracy of dual-source computed tomography (DSCT) with reference to invasive coronary angiography in the diagnosis of coronary artery disease (CAD) on a per-patient as well as on a per-segment basis. Materials and Methods: Thirty-five patients with known or suspected CAD … Read more

  Article in German: Dual-source-CT in der Diagnostik des Thoraxschmerzes Abstract Background: With the depiction of pulmonary arteries, coronary arteries, and the aorta, CT angiography of the chest offers a comprehensive diagnostic work-up of unclear chest pain. The aim of this study was to assess … Read more

Abstract The relation of heart rate and image quality in the depiction of coronary arteries, heart valves and myocardium was assessed on a dualsource computed tomography system (DSCT). Coronary CT angiography was performed on a DSCT (Somatom Definition, Siemens) with high concentration contrast media (Iopromide, Ultravist 370, Schering) in 24 patients … Read more

Aims: The aim of the present study was to assess the clinical performance of a dual X-ray source multi-slice CT (MSCT) with high temporal resolution to assess the coronary status in patients with an intermediate pretest likelihood for significant coronary artery disease (CAD) without using negative chronotropic pretreatment. Methods and results: … Read more