Clinical Advancements in Angiographic Imaging

phaseXact™ – Automatic Phase Cardiac Reconstruction Figure 5: Another case where phaseXact ﬁnds the optimal phase. This patient had a steady heart rate in the mid 60’s. phaseXact shows better continuity of the RCA and allows visualization of the acute marginal branch not seen with the conventional approach. motion map (the darkest regions of Figure 2) for automatic reconstruction and review. The conventional method of analysis creates much more data that needs to be transferred and analyzed. A typical model includes the reconstruction of 3 to 5 different cardiac phases, or more, for review. With a typical cardiac phase requiring 300 to 400 images, this can mean that upwards of 2000 images may be sent for review. On the other hand, when phaseXact is used, only the images from the phase with the least motion are sent for analysis, thus reducing the required data to as little as one ﬁ fth of the conventional method. Figure 3 shows the average number of images sent for review in 12 consecutive cases with and without phaseXact. This dramatic reduction References in data handling and interpretation requirements will reduce the cost and enhance the workﬂow of any busy cardiac imaging practice. phaseXact not only minimizes the transfer and archival needs, thus enhancing the workﬂow, but it also gives higher quality images for interpretation. Use of the conventional method only provides images in 5% phase increments. Due to the precise nature of modern CT hardware, this sometimes results in adequate, diagnostic image quality. However, since phaseXact analyzes in 1 msec increments after the R-peak, it often ﬁ nds optimal phases that would not ever be “checked” by the manual method. Figure 4 shows a case with image quality that would be considered visually acceptable for interpretation and would be selected as input into a post-processing algorithm. However, the phaseXact reconstruction reveals vastly improved sharpness of the entire vessel as well as much clearer delineation of the tiny branches. The contrast of these two reconstructions clearly demonstrates the power of optimal phase selection using ﬁ ne, 1 msec phase resolution. Only by analyzing every possible phase can the optimal reconstruction be determined. Another clinical example (Figure 5) illustrates the advantage of phaseXact, even in patients with a relatively stable heart rate (in this case, between 65 and 68 beats per minute throughout the CT data acquisition). The reconstruction centered at about 75% of the R-R interval suffers from misregistration and consequently the delineation of the RCA. phaseXact determined the true best phase at 411 ms after the initial R-wave, and this reconstruction shows marked improvement in the continuity of the RCA as well as excellent visualization of the acute marginal branch. Accurate phase selection is a critical step in cardiac CT angiography. Poor selection can degrade image quality, increase interpretation time and compromise diagnostic conﬁdence. By examining the cardiac motion of each patient during their scan, phaseXact automatically ﬁ nds the phase with the least motion. By automating this aspect of coronary CTA, phaseXact streamlines workﬂow, reduces interpretation time and improves diagnostic conﬁdence. CA 1. Wintersperger BJ, Nikolaou K, von Ziegler F, Johnson T, Rist C, Leber A, Flohr T, Knez A, Reiser MF, Becker CR, 2006 Image quality, motion artifacts, and reconstruction timing of 64-slice coronary computed tomography angiography with 0.33-second rotation speed. Invest Radiol May; 41(5):436-42. 2. Morgan-Hughes GJ, Owens PE, Marshall AJ, Roobottom CA, 2006 Multi-detector row CT coronary angiography: inﬂuence of reconstruction technique and heart rate on image quality. Radiology Jan; 238(1):75-86. 3. Herzog C, Arning-Erb M, Zangos S, Eichler K, Hammerstingl R, Dogan S, Ackermann H, Vogl TJ, 2006, Multi-detector row CT coronary angiography: inﬂuence of reconstruction technique and heart rate on image quality. Radiology Jan; 238(1):75-86. 4. Leschka S, Wildermuth S, Boehm T, Desbiolles L, Husmann L, Plass A, Koepﬂi P, Schepis T, Marincek B, Kaufmann PA, Alkadhi H, 2006 Noninvasive coronary angiography with 64-section CT: effect of average heart rate and heart rate variability on image quality. Radiology Nov;241(2):378-85. A public ation produced by Toshiba Medic al Sys t ems Oc tober 2 0 0 7 7

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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