Pamela T. Johnson

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Spiral computed tomographic (CT) data sets coupled with a real-time volume-rendering technique allow creation of accurate three-dimensional (3D) images that can be used for a wide range of clinical applications. The image contrast of and relative pixel attenuations in the final image can be interactively modified by the user in real time by manipulating(More)
Increasing concerns about radiation dose have led CT manufacturers to further develop radiation dose reduction tools in the latest generation of CT scanners. These tools include automated tube current modulation, automated tube potential selection, and iterative reconstruction. This review details the principles underlying each of these 3 dose reduction(More)
PURPOSE Many hospitals experience one or more retained surgical item events per year, with risk of patient morbidity and medicolegal consequences. We hypothesized that the confidence and performance of the radiologist would be enhanced by prior training in retained surgical item detection and by prior exposure to commonly employed surgical instruments and(More)
The preceding manuscript describes the principles behind the Interactive Watershed Transform (IWT) segmentation tool. The purpose of this manuscript is to illustrate the clinical utility of this editing technique for body multidetector row computed tomography (MDCT) imaging. A series of cases demonstrates clinical applications where automated segmentation(More)
OBJECTIVE The purpose of this study was to evaluate the accuracy of CT angiography with volume rendering for quantifying vascular stenoses in vitro. MATERIALS AND METHODS Vascular models with three degrees of stenosis (33%, 67%, and 83%) were imaged at three orientations to the axial plane (parallel, perpendicular, or 45 degrees ) using helical CT with(More)
OBJECTIVE The adrenal gland can enlarge or alter morphology in the presence of a range of nonneoplastic entities, including hyperplasia, hemorrhage, infection, or cystic mass. This article presents a description and representative CT images for each of these disorders. CONCLUSION Proper characterization is essential to ensure that life-threatening(More)
Metastatic disease to the small bowel is rare; however, it is important to recognize that when it does occurs a variety of complications are possible including obstruction, gastrointestinal bleeding, intussusception, and bowel perforation. We present here an unusual case of small bowel metastases in a patient with known metastatic liposarcoma in which the(More)
The introduction of spiral computed tomography from the days of single-slice spiral to today's 64-row multidetector computed tomography and beyond creates datasets with unprecedented spatial and temporal resolution. The key to computed tomography imaging in the big picture is not in the acquisition of data, but in the use of the data acquired. By(More)
Segmentation of volumetric computed tomography (CT) datasets facilitates evaluation of 3D CT angiography renderings, particularly with maximum intensity projection displays. This manuscript describes a novel automated bone editing program that uses an interactive watershed transform (IWT) technique to rapidly extract the skeletal structures from the volume.(More)
LEARNING OBJECTIVES After reading this article and taking the test, the reader will be able to: Ⅲ Describe the technical advantages and disadvantages of volume rendering and maximum intensity projection (MIP) for evaluation of CT an-giographic data sets. Ⅲ Explain the value of volume rendering for optimizing tumor staging in solid organs such as the liver,(More)