Head-to-Head Comparison of Dual-Source and Split-Beam Filter Multi-Energy CT versus SPECT/CT for Assessing Lobar Lung Perfusion in Emphysema

Purpose: To evaluate dual-source and split-beam filter multi-energy chest CT in assessing pulmonary perfusion on a lobar level in pa-tients with lung emphysema, using perfusion SPECT as the reference standard.Materials and Methods: Patients with emphysema evaluated for lung volume reduction therapy between May 2016 and February 2021 were retrospectively included. All patients underwent SPECT and either dual-source or split-beam filter (SBF) multi-energy CT. To calculate the fractional lobar lung perfusion (FLLP), SPECT acquisitions were co-registered with chest CT scans (hereafter, SPECT/ CT) and semi-manually segmented. For multi-energy CT scans, lung lobes were automatically segmented using a U-Net model. Segmentations were manually verified. The FLLP was derived from iodine maps computed from the multi-energy data. Statistical analysis included Pearson and intraclass correlation coefficients and Bland-Altman analysis.Results: Fifty-nine patients (30 male, 29 female; 31 underwent dual-source CT, 28 underwent SBF CT; mean age for all patients, 67 years & PLUSMN; 8 [SD]) were included. Both multi-energy methods significantly correlated with the SPECT/CT acquisitions for all individual lobes (P < .001). Pearson correlation concerning all lobes combined was significantly better for dual-source (r = 0.88) than for SBF multi-energy CT (r = 0.78; P = .006). On the level of single lobes, Pearson correlation coefficient differed for the right upper lobe only (dual-source CT, r = 0.88; SBF CT, r = 0.58; P = .008).Conclusion: Dual-source and SBF multi-energy CT accurately assessed lung perfusion on a lobar level in patients with emphysema com-pared with SPECT/CT. The overall correlation was higher for dual-source multi-energy CT.

Automated summary

The purpose of this study was to evaluate the use of dual-source and split-beam filter multi-energy chest CT in assessing pulmonary perfusion in patients with lung emphysema, using perfusion SPECT as the reference standard. The results showed that both dual-source and split-beam filter multi-energy CT had significant correlations with SPECT/CT for all lobes, and dual-source CT had a higher overall correlation.