The influence of attenuation and scatter compensation on the apparent distribution of Tc-99m sestamibi in cardiac slices

Citation
Ph. Pretorius et al., The influence of attenuation and scatter compensation on the apparent distribution of Tc-99m sestamibi in cardiac slices, J NUCL CARD, 8(3), 2001, pp. 356-364
Citations number
31
Categorie Soggetti
Cardiovascular & Respiratory Systems
Journal title
JOURNAL OF NUCLEAR CARDIOLOGY
ISSN journal
10713581 → ACNP
Volume
8
Issue
3
Year of publication
2001
Pages
356 - 364
Database
ISI
SICI code
1071-3581(200105/06)8:3<356:TIOAAS>2.0.ZU;2-M
Abstract
Background. Our objective was to study the differences in relative count di stributions in the left ventricular walls with attenuation compensation (AC ) versus AC and triple-energy-window scatter compensation (SC), compared wi th standard filtered backprojection (FBP), Methods ann Results, Two hundred patients identified as having normal cardi ac perfusion with FBP after undergoing either pharmacologically or physiolo gically induced stress were included in this study Projection data were rec onstructed with FBP, 10 iterations of ordered-subset expectation-maximizati on (OSEM) with AC, and OSEM with AC+SC, A comparison was made of average pe rcentage of maximum counts within each of 9 regions of CEqual (Marconi Medi cal Systems, Inc, Cleveland, Ohio) polar maps tie, the apex, 3 midventricul ar regions, and 4 basal regions), Compared with OSEM(AC), a slight decrease at the apex exists when SC is included, The elevated inferior-to-anterior count ratio in the midventricular and basal regions noted with OSEM(AC) dec reased to close to 1.0 with OSEM(AC+SC). The anterior-to-lateral ratio for both regions was closest to 1.0 for OSEM(AC+SC), In the midventricular regi on, the lateral-to-septal ratio decreased further below 1.0 with OSEM(AC+SC ) than it did with OSEM(AC). This was the only basal ratio not to improve t o close to 1.0 with OSEM(AC+SC). In a subset of patients identified at the time of clinical reading as having a possible attenuation-caused decrease i n the inferior region, AC elevated the inferior-to-anterior ratio to above 1.0 for the midventricular region. AC+SC resulted in a ratio of near 1.0 fo r this region. In another subset of patients identified as having anterior attenuation artifacts, compensation methods (either AC or AC+SC) failed to show an improvement compared with FBP. Conclusions. AC and SC improve the uniformity of the polar map, especially by bringing the inferior-to-anterior ratio closer to 1,0, Further investiga tion is necessary to determine the cause of the increased midventricular se ptal polar map count. In addition, the subset of patients identified as hav ing breast-like attenuation artifacts causing a decreased polar map count i n the anterior mall (relative to the inferior wall) also needs further atte ntion.