Yi-Ting Wang MD, Presenter: Nothing to Disclose

Chung-Yi Yang MD, Abstract Co-Author: Nothing to Disclose

Yun Shen PhD, Abstract Co-Author: Employee, General Electric Company

Wen-Jeng Lee MD, Abstract Co-Author: Nothing to Disclose

Jong-Kai Hsiao MD, Abstract Co-Author: Nothing to Disclose

Hon-Man Liu MD, Abstract Co-Author: Nothing to Disclose

To evaluate the impact on the image quality and the accuracy of coronary stenotic rate measurement of the two reconstruction algorithms (halfscan and multi-sector) using a pulsating cardiac phantom with different heart rates.

Simulated coronary arteries with stenosis of three different diameters (3, 4, and 5mm) and three different stenotic rates (25, 50, and 75%) were prepared. After scanning with fixed pitch of 0.16 and 0.35 second gantry rotation time on a 64-slice MDCT (GE LightSpeed VCT), both the two reconstruction algorithms (halfscan and multi-sector) were done for each cardiac pulsation of 40, 50, 60, 70, 80, 90, 100, 110, and 120 beats per minute (bpm). Visual assessement of the quality scores and manual measurement of the stenotic rates were done by two experienced radiologist on the workstation.

Better diagnostic accuracy was correlated with multi-sector reconstruction (p=0.05), slower heart rate (p<0.001) and larger luminal diameter (p=0.014); it was not correlated with observers and stenotic rates. There was no significant difference below heart rate 70bpm. The increased number of nonassessable segments was correlated with halfscan reconstruction (p=0.004) and higher heart rates (p<0.001). Halfscan reconstruction had better quality scores when heart rate was below 60 bpm, while multi-sector reconstruction had better quality scores when heart rate was above 90 bpm. Among heart rates 60~90 bpm, both reconstruction modes had similar quality scores. Excluding the nonassessable segments, both reconstruction algorithms acquired similar mean measured stenotic rates with similar standard deviations.

At higher HR (above 70 bmp), multi-sector reconstruction achieves better temporal resolution, less nonassessable segments, better quality scores, less banding artifacts, and better accuracy for stenotic rate measurement in this phantom study.

With a 64-slice MDCT, multi-sector reconstruction should be used at heart rate above 70 bpm.

Wang, Y, Yang, C, Shen, Y, Lee, W, Hsiao, J, Liu, H, The Accuracy of Coronary Stenosis Measurement in 64-slice MDCT with Different Reconstruction Modes: A Preliminary Study Using a Pulsating Cardiac Phatom.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5009372.html