Kuniyuki Tashiro, Presenter: Nothing to Disclose

Shinya Shiraishi MD, Abstract Co-Author: Nothing to Disclose

Seiji Tomiguchi MD, Abstract Co-Author: Nothing to Disclose

Yasuyuki Yamashita MD, Abstract Co-Author: Nothing to Disclose

To evaluate the effect of CT-based attenuation correction on the uniformity of Tl-201 myocardial distribution in normal subjects.

We enrolled 35 adults (16 men and 19 women) without coronary arterial disease. All underwent Tl-201 myocardial SPECT and low-dose CT imaging using a combined SPECT/CT system. Both types of images were acquired in one session using a CT table without moving the subject's position. Attenuation correction was performed using an attenuation coefficient map produced by the CT image. Attenuation-corrected (AC) and non-corrected (NC) short axial images were reconstructed using an OSEM algorithm. AC and NC images were displayed with a polar map each of which was divided into 5 segments (apical, septal, anterior, inferior, and lateral wall). The uniformity of the Tl-201 myocardial distribution was evaluated quantitatively using the standard deviation (SD) of the mean counts in all 5 segments. The SD values of AC and NC images were compared.

The mean SD values were 4.3 and 5.3 for the AC- and NC images, respectively. In all cases, the SD values were lower for the AC than the NC images. In men, the mean SD was 4.4 on AC- and 6.3 on NC images; in women it was 4.2 and 4.5, respectively. A significant improvement in the uniformity of Tl-201 myocardial distribution was obtained in men but not in women.

CT-based attenuation correction is useful for improving the uniformity of Tl-201 myocardial distribution in men but not in women.

CT-based attenuation correction can be improved a diagnosis of myocardial Tl-201 scintigraphy.

Tashiro, K, Shiraishi, S, Tomiguchi, S, Yamashita, Y, Effect of CT-based Attenuation Correction on the Uniformity of Myocardial Tl-201 Distribution in Normal Subjects: A Study Using a Combined SPECT/CT System.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4430656.html