Variability of left ventricular ejection fraction and volumes with quantitative gated SPECT: influence of algorithm, pixel size and reconstruction parameters in small and normal-sized hearts

Abstract

In patients with a normal-sized heart, LVEF and volume estimates computed from different commercially available software packages for quantitative gated SPECT are well correlated. LVEF and volumes are only slightly sensitive to changes in matrix size. Smoothing, by contrast, is associated with significant changes in volumes but usually not in LVEF values. However, owing to the specific characteristics of each algorithm, software should not be interchanged for follow-up in an individual patient. In small hearts, on the other hand, both the used software and the matrix size or smoothing significantly influence the results of quantitative gated SPECT. LVEF values in the higher range are frequently observed with all the studied software except for SU-Segami. A larger matrix or a sharper filter could be suggested to enhance the accuracy of most commercial software, more particularly in patients with a small heart.

Influence of Reconstruction Parameters During Filtered Backprojection and Ordered-Subset Expectation Maximization in the Measurement of the Left-Ventricular Volumes and Function During Gated SPECT

“…The parameters of both these reconstruction methods can modify the quantitative results of myocardial perfusion imaging (e.g., the LVEF) (4,7,10,11,29).…”

“…For determination of a phantom's volumes and LVEF after reconstruction, QGS software has been shown to be fast (8) and reproducible (10,12) and gives LVEF values that compare well with those obtained by other reliable techniques (1,5,6,8,10). Nevertheless, it has been shown that QGS underestimates LV volumes (4,12,29,35), resulting in an overestimation of LVEF (29).…”

“…Gated SPECT permits, in fact, the determination of global and regional function of the left ventricle (4,6,(10)(11)(12); however, the measurement of LV quantitative param-eters is dependent on endocardial surface detection by the reconstruction algorithms (4,5,9,11,13).…”

The expanding role of left ventricular functional assessment using gated myocardial perfusion SPECT: the supporting actor is stealing the scene

“…On the other hand, in patients with a relatively small left ventricular cavity, for instance in women or children, or with left ventricular hypertrophy, the endocardial border may be inaccurately identified, leading to underestimation of the end-systolic volume [46,47]. This causes significant overestimation of the left ventricular ejection fraction, although differences exist in the degree of overestimation using the various available processing algorithms [47,48]. It has been suggested that proper filtering and zooming may reduce the inaccuracy of gated SPECT in these subjects [46,47].…”

“…This causes significant overestimation of the left ventricular ejection fraction, although differences exist in the degree of overestimation using the various available processing algorithms [47,48]. It has been suggested that proper filtering and zooming may reduce the inaccuracy of gated SPECT in these subjects [46,47]. In spite of the finding of very small values in females, a recent article has demonstrated that preserved left ventricular ejection fraction and normal left ventricular volumes have an incremental prognostic value over perfusion abnormalities in women as well as in men [49].…”