Clinical Advancements in Angiographic Imaging

Pre Contrast Volume Post Contrast Volume Subtracted DICOM Volume – A B = C Figure 1: (A) Toshiba’s SURESubtraction works by identifying high HU voxels on a pre-contrast image data set, (B) then registers these voxels with a standard contrast-enhanced set of images, (C) and ﬁnally produces a subtracted CT-DSA data set, free of bone and with greatly improved visualization of the contrast-enhanced vessels. Subtraction prevents structured noise from creating artifacts in the subtracted data set by employing orbital synchronization to ensure that both acquired datasets have identical helical paths through the head. By identifying only the highest-density structures on the non-contrast data set and creating a template image, SURE Subtraction avoids many of the noise enhancement complications that plague practitioners of simple manual subtraction and ensures that the enhanced vessels remain intact. Finally, by employing a robust, rigid registration algorithm capable of resolving volume shifts down to a millionth of a voxel, SURE Subtraction obviates the need for special head immobilization measures and delivers unparalleled bone removal and image quality. SURE more brain CTAs per day on patients referred to us for initial screening or as follow-up for intra-cranial or extra-cranial stenting or aneurysm repair. Additionally, we are utilizing CTA to detect cerebral vasospasm. For new patients with cerebral vascular ischemia or subarachnoid hemorrhage, we use CTA to detect aneurysms or arterial stenosis or occlusion. It is truly a part of our daily work here. Now, we can review a “subtracted” Neurovascular CTA in about ﬁve minutes. What are the biggest challenges in analyzing the data? Dr. Peters: The information still comes from axial images – but the challenge is handling the overwhelming volume, which, for a regular CTA acquisition of the brain using a 32-slice CT scanner, can What percentage of your work is brain CTA? Dr. Peters: Probably a ﬁfth of our workload is brain CTAs, both at the department and imaging center levels. Dr. Jahromi: At least 50 percent, if not more; it’s a difﬁcult question to answer since almost all of our patients undergo a CTA at some point. We perform at least 10 or amount to as many as 500 separate images through the brain. We have a number of algorithms available that can recreate multi-planar reformations or 3D reconstructions of that data – but neither addresses the problem of the overlying bone. The real challenge is to remove the skull to see the blood vessels like using regular digital subtraction angiography with a catheter. Conventional CTA doesn’t allow us to adequately look at certain areas in the skull region, especially at the base. Seeing the vessels in this area is absolutely crucial since most aneurysms occur within the Circle of Willis, an area about the size of a half-dollar intimately adjacent to the skull base. Our major difﬁculty is analyzing this data for the location of an aneurysm, and separating the bones from the blood vessels to be able to identify the disease. Dr. Jahromi: In addition to those challenges, a large number of physicians involved with intervention work are not familiar with reading CTAs. They are used to conventional angiograms that depict the entire vessel without bone or cross-sectional Oc tober 2 0 0 7 A public ation produced by Toshiba Medic al Sys t ems 17

Table of Contents Feed for the Digital Edition of Clinical Advancements in Angiographic Imaging

Contents PhaseXact™: Automatic Phase Cardiac Reconstruction Giant Internal Carotid Aneurysm Non-Contrast SSFP Time-SLIP Imaging: Renal Artery Stenosis Springhill Medical Center: A Partnership to Improve Patient Safety Anterior Cerebral Artery Aneurysm Right Coronary Artery (RCA) lesion with SUREPlaque analysis Neurovascular CTA: When every second counts

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