Key result
Dynamic 4DCT identifies greater LAA stasis in AF than sinus rhythm, independent of CHA2DS2-VASc score.
Why the study?
Can dynamic contrast 4DCT with gamma-variate modeling quantify left atrial appendage blood transport and stasis in patients with atrial fibrillation?
Observational (n=93)
Can dynamic contrast 4DCT with gamma-variate modeling quantify left atrial appendage blood transport and stasis in patients with atrial fibrillation?
Voxel-wise quantification of LAA blood stasis using dynamic contrast 4DCT is technically feasible in AF patients and captures hemodynamic differences between AF and sinus rhythm that do not correlate with CHA2DS2-VASc scores.
Answers are grounded in this paper and cite their sources.
4DCT LAA transport mapping may refine AF stroke risk assessment; leaves open whether metrics improve prediction over clinical scores.
Background Current stroke risk stratification in atrial fibrillation (AF) relies on clinical factors with known limitations. Blood stasis in the Left Atrial Appendage (LAA) promotes thrombus formation, contributing to embolic stroke. Our objective is to map contrast transport throughout the LAA volume with 4DCT. Methods Patients being treated for AF underwent dynamic contrast 4DCT. Hounsfield unit (HU) vs. time curves were fitted voxel wise using gamma-variate models. Three LAA blood transport metrics were extracted: (1) increase in residence time between distal LAA voxels and the LA/LAA orifice (ΔRT); (2) ratio of peak HU enhancement in distal LAA voxels to peak HU in the LA/LAA orifice (ΔHU); and (3) total volume of delayed filling (Vstasis) in the LAA. A composite "LAA Transport Index" (LAATI) was computed using principal component analysis. Results Among all 93 patients, a wide range of delayed transport in the LAA was observed with: 0 < ΔRT < 30 s, 0.02 < ΔHU < 1, 0 < Vstasis < 13 mL. Patients imaged during sinus rhythm (n = 26) had rapid filling of the entire LAA with 0 < ΔRT < 4.7 s, 0.65 < ΔHU < 1, 0 < Vstasis < 1.0 mL. In comparison, patients in AF had values over the entire range ΔRT, ΔHU and Vstasis. For patients imaged in sinus the mean LAATI = -1.06 ± 0.4, and for those imaged in AF the mean LAATI = 0.43 ± 1.7. LAATI did not correlate with CHA2DS2-VASc (p = 0.44) or chicken wing morphology (p = 0.21). Conclusions 4DCT-based voxel-wise quantification of LAA contrast transport using gamma-variate modeling is technically feasible. Further studies are required to determine its potential value for personalized stroke-risk assessment.
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Severance et al. (2026) conducted an observational in Atrial fibrillation (n=93). Dynamic contrast 4DCT with gamma-variate voxel-wise modeling vs. Patients imaged during sinus rhythm (n=26) vs. atrial fibrillation was evaluated on Composite Left Atrial Appendage Transport Index (LAATI) and blood transport metrics (ΔRT, ΔHU, Vstasis). Dynamic contrast 4DCT quantified LAA blood stasis, showing higher mean LAATI in AF (0.43±1.7) than sinus rhythm (-1.06±0.4) and no correlation with CHA2DS2-VASc (p=0.44).
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