QGS ejection fraction reproducibility in gated SPECT comparing pre-filtered and post-filtered reconstruction

• Published in: Nuclear medicine communications Vol. 27; no. 1; p. 57
• Main Authors: Wheat, Janelle M, Currie, Geoffrey M
• Format: Journal Article
• Language: English
• Published: England 01.01.2006
• Subjects: Algorithms; Exercise Test; Gated Blood-Pool Imaging - methods; Humans; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Reproducibility of Results; Sensitivity and Specificity; Signal Processing, Computer-Assisted; Software; Stroke Volume; Tomography, Emission-Computed, Single-Photon - methods; Ventricular Dysfunction, Left - diagnostic imaging
• ISSN: 0143-3636
• DOI: 10.1097/01.mnm.0000188223.01366.44

The aim of this investigation was to compare the QGS determined functional parameters using pre-filtering to that using post-filtering in the gated myocardial perfusion single photon emission computed tomography (SPECT) reconstruction process. A total of 25 patient files were examined, each with both a gated rest and gated stress study, and were reconstructed using two strategies. The first employed pre-filtering with a Butterworth low pass filter (order 4.0 and cut-off 0.21) and the second employed post-filtering with a Butterworth low pass filter (order 5.0 and cut-off 0.21). Following reconstruction and reorientation, gated short axis slices were evaluated with QGS software. The mean ejection fraction for the post-filtered data was 49.5% (95% CI, 45.8-53.1%) and for the pre-filtered data was 54.8% (95% CI, 51.4-58.1%). Excellent correlation was demonstrated between the pre- and post-filtered ejection fractions with a correlation coefficient of 0.964. The mean difference between matched pairs of pre- and post-filtered ejection fraction data was 5.3% (95% CI, 4.3-6.3%). The match pair t-test demonstrated a statistically significant difference between matched pairs (P<0.0001) and a statistically significant difference was shown between the means (P=0.005). The impact of performing pre-filtering on data in the reconstruction process is significant with a 5.3% increase in the calculated ejection fraction over post-filtering. Clearly, this has the potential to undermine diagnostic and prognostic roles of functional parameters.