Assessment of the impact of post-processing approaches on absolute myocardial blood flow quantification using cardiac-dedicated CZT-SPECT: A retrospective observational study

Quantitative myocardial blood flow (MBF) assessment using cardiac-dedicated cadmium-zinc-telluride (CZT) single photon emission computed tomography (SPECT) has emerged as a promising noninvasive approach for evaluating both macrovascular and microvascular coronary function. However, the reliability and comparability of MBF measurements are substantially influenced by variations in post-processing methodologies, including the application of attenuation correction (AC) and scatter correction (SC) techniques. Despite the increasing clinical adoption of CZT-SPECT for absolute perfusion quantification, systematic evaluations comparing different post-processing strategies remain limited. This study aimed to evaluate the impact of various post-processing approaches on absolute quantitative MBF measurements obtained through CZT-SPECT, with particular focus on AC and SC methodologies. Seventy patients who underwent dynamic CZT-SPECT myocardial perfusion imaging were retrospectively included, comprising 35 Tc-99m-methoxyisobutylisonitrile patients and 35 Tc-99m-tetrofosmin patients. Each raw imaging dataset was independently reprocessed using Corridor 4DM under 3 correction strategies – no correction, attenuation correction, and attenuation + scatter correction (ACSC) – as well as using MyoFlowQ. Repeated-measures analysis of variance or Friedman tests with Holm-adjusted pairwise comparisons were used to compare the Corridor 4DM processing strategies, and agreement between Corridor 4DM with ACSC and MyoFlowQ was assessed using Bland–Altman analysis. Rest and stress MBF differed significantly across the Corridor 4DM processing strategies (both P < .001). Myocardial flow reserve (MFR) differences were tracer-dependent: no overall difference was observed in global left ventricular values in the Tc-99m-methoxyisobutylisonitrile cohort ( P = .121), whereas a significant difference was observed in the Tc-99m-tetrofosmin cohort ( P = .002). Compared with Corridor 4DM using ACSC, MyoFlowQ yielded higher stress MBF and MFR values (bias, 1.19–1.31 mL·g −1 ·min −1 ; 95% limits of agreement, –0.30 to 2.68), with moderate inter-software correlation ( r = 0.44–0.59, P < .01). Post-processing methodology significantly influenced absolute MBF quantification in CZT-SPECT imaging. Within Corridor 4DM, correction strategies affected MBF estimates, and MyoFlowQ yielded higher stress MBF and MFR values than Corridor 4DM using ACSC, indicating that these post-processing approaches are not directly interchangeable.