Tom Brady

Publications of Tom Brady

• Usefulness of coronary computed tomographic angiography to assess suitability for revascularization in patients with significant coronary artery disease and angina pectoris.

  Authors: Tej N Sheth, Johannes Rieber, Eline A Q Mooyaart, Antonio Pena, Suhny Abbara, Ricardo C Cury, Tom Brady, Udo Hoffmann

  The American journal of cardiology. 12/2006; 98(9):1198-201.

  Coronary computed tomographic angiography (CTA) accurately excludes the presence of coronary stenoses in selected patient populations. However, it remains unclear whether coronary CTA has theCoronary computed tomographic angiography (CTA) accurately excludes the presence of coronary stenoses in selected patient populations. However, it remains unclear whether coronary CTA has the potential to replace invasive coronary angiography as a tool to assess a patient's suitability for revascularization as determined by the characterization of lesion morphology in patients with significant coronary artery disease. Coronary CTA (64-slice computed tomography) was performed before invasive coronary angiography in 29 patients. We evaluated the accuracy of CTA for the detection of complex lesion morphology, including the presence of severe calcium, total occlusions, and ostial or bifurcation location, and compared the results with those of invasive angiography. On CTA, 10 of 69 lesions (15%) were not evaluable for any feature of complex lesion morphology. Of the evaluable lesions, CTA detected >or=1 feature of complexity in 58% of lesions, corresponding to a sensitivity of 88% (23 of 26) and a specificity of 83% (24 of 29). For those single features, the sensitivity of CTA was 100% for the presence of severe calcium, 93% for total occlusions, and 60% and 80% for the detection of ostial and bifurcation lesions, respectively. The specificity was high for total occlusions (97%), ostial lesions (97%), and bifurcations (100%). It was moderate (85%) for severe calcium. Severe calcium precluded the evaluation of other features of complex lesion morphology in 6 lesions (11%). In conclusion, invasive selective coronary angiography remains the cornerstone to assess a patient's suitability for revascularization given the high proportion of unevaluable segments and segments with severe calcium that precluded adequate revascularization planning on CTA.

• Ultra-high resolution flat-panel volume CT: fundamental principles, design architecture, and system characterization.

  Authors: Rajiv Gupta, Michael Grasruck, Christoph Suess, Soenke H Bartling, Bernhard Schmidt, Karl Stierstorfer, Stefan Popescu, Tom Brady, Thomas Flohr

  European radiology. 07/2006; 16(6):1191-205.

  Digital flat-panel-based volume CT (VCT) represents a unique design capable of ultra-high spatial resolution, direct volumetric imaging, and dynamic CT scanning. This innovation, when fullyDigital flat-panel-based volume CT (VCT) represents a unique design capable of ultra-high spatial resolution, direct volumetric imaging, and dynamic CT scanning. This innovation, when fully developed, has the promise of opening a unique window on human anatomy and physiology. For example, the volumetric coverage offered by this technology enables us to observe the perfusion of an entire organ, such as the brain, liver, or kidney, tomographically (e.g., after a transplant or ischemic event). By virtue of its higher resolution, one can directly visualize the trabecular structure of bone. This paper describes the basic design architecture of VCT. Three key technical challenges, viz., scatter correction, dynamic range extension, and temporal resolution improvement, must be addressed for successful implementation of a VCT scanner. How these issues are solved in a VCT prototype and the modifications necessary to enable ultra-high resolution volumetric scanning are described. The fundamental principles of scatter correction and dose reduction are illustrated with the help of an actual prototype. The image quality metrics of this prototype are characterized and compared with a multi-detector CT (MDCT).

• The Use of CTA in the Chest Pain Center: A Perspective.

  Authors: Stephan Achenbach, Dieter Ropers, Falk-Karsten Pohle, Udo Hoffmann, Maros Ferencik, R Cury, S Abbara, Tom Brady, Werner Daniel

  Critical pathways in cardiology. 07/2004; 3(2):87-93.

  Suitable imaging methods to reliably rule out coronary artery disease as the underlying condition might be beneficially applied in the workup of patients with acute chest pain. The temporal andSuitable imaging methods to reliably rule out coronary artery disease as the underlying condition might be beneficially applied in the workup of patients with acute chest pain. The temporal and spatial resolution of computed tomgraphy and electron beam computed tomography has seen continuous improvements over the past years. Current scanner generations permit relatively reliable visualization of the coronary arteries and several studies have demonstrated a high negative predictive value to rule out coronary artery stenoses. Even though applications in the context of acute coronary syndromes have not yet been specifically evaluated, it seems likely that computed tomography imaging may develop into a tool that can be integrated into the workflow in chest pain centers once appropriate studies have been performed.

• Inherently 3-dimensional method for measurement of computed tomographic resolution anisotropy.

  Authors: Stephen E Jones, Michael Grasruck, Bernhard Schmidt, Ijad Madisch, Ryan Egeland, Tom Brady, Rajiv Gupta

  Journal of computer assisted tomography. 30(6):962-71.

  OBJECTIVE: Current techniques to measure computed tomography (CT) spatial resolution use separate methods for in-plane and out-of-plane directions. The growing use of near-isotropic voxel sizeOBJECTIVE: Current techniques to measure computed tomography (CT) spatial resolution use separate methods for in-plane and out-of-plane directions. The growing use of near-isotropic voxel size necessitates a new single method that inherently measures resolution in any direction. METHOD: We introduce a method using a set of numerous glass microspheres suspended in a small volume from which a mean sphere image is constructed. Projecting asymptotes after imaging different microsphere sets with decreasing diameters provides an inherently 3-dimensional measure of spatial resolution and anisotropy. We apply the method to both a flat-panel and multidetector CT scanner. RESULTS: The full-width at half-maximum from line profiles through mean sphere in transverse directions corresponds to known microsphere diameters. Increased longitudinal full-width at half-maximum corresponds to known anisotropy, which is larger for a multidetector CT scanner than for a flat-panel CT scanner. CONCLUSIONS: A new single method to measure CT resolution is inherently isotropic.

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