Utilization of thick (>3 mm) maximum intensity projection images in coronary CTA interpretation

Abstract

elevated the role of the Emergency Radiologist in the screening of trauma patients or patients with suspected pulmonary embolism (PE), 64-slice multidetector computed tomography (MDCT) and advanced image postprocessing workstations are poised to change the screening algorithms in patients who present to emergency medicine facilities with chest pain. As emergency radiologists acquire and gain experience with advanced CT technology, they should assume a leadership role in the imaging evaluation for a considerable fraction of this patient population, over 5 million patients annually. Less than 20% of the total patient population has coronary artery disease, emphasizing the potential of the high negative predictive value of CT. Moreover, the image acquisition and postprocessing software, already capable of chest pain imaging, continues to evolve. It may be the case that chest pain imaging will mirror the history of PE computed tomography angiography (CTA). That is, early single slice helical CT scanners with relatively thick slices, slow gantry rotation times, and evolving postprocessing tools were cumbersome, but they were both noninvasive and diagnostic. As CT evolved and Emergency Radiologists gained familiarity with the imaging and interpretation, PE CTA protocols became streamlined and routine, and are now a mainstay of our field. With the opportunity of expanding Emergency Radiology with chest pain patients comes the challenge of staffing, education, and both accurate and timely reporting. This letter offers some comments on accurate and timely reporting. In order to spatially resolve a proximal and midcoronary artery that has a 3-mm diameter, coronary CTA requires thin section (<1 mm) imaging with reconstructed images that are roughly 0.5 mm. Moreover, coronary CTA requires electrocardiogram (ECG) gating and thin section data sets are created throughout the cardiac cycle. The increased utilization of ECG-gated and thin section imaging will usher in a paradigm shift in the use of image postprocessing software in Emergency Radiology. Specifically, postprocessing software packages will advance from the role of a supplementary, problem-solving tool to become the primary means of image interpretation. In addition to improved handling of very large data sets, postprocessing software packages enable the user to create multiplanar reformatted (MPR) and maximum intensity projection (MIP) images [1] in multiple planes. Vendors have also designed software supporting specific workflows in coronary CT interpretation, with the intent of improving efficiency of either the radiologist or the cardiologist.