Analysis of Pulmonary Vein Antrums Motion with Cardiac Contraction Using Dual-Source Computed Tomography.
OBJECTIVE
The purpose of the study was to determine the extent of displacement of the pulmonary vein antrums resulting from the intrinsic motion of the heart using 4D cardiac dual-source computed tomography (DSCT).


METHODS
Ten consecutive female patients were enrolled in this prospective planning study. In breath-hold, a contrast-injected cardiac 4-dimensional (4D) computed tomography (CT) synchronized to the electrocardiogram was obtained using a prospective sequential acquisition method including the extreme phases of systole and diastole. Right and left atrial fibrillation target volumes (CTVR and CTVL) were defined, with each target volume containing the antral regions of the superior and inferior pulmonary veins. Four points of interest were used as surrogates for the right superior and inferior pulmonary vein antrum (RSPVA and RIPVA) and the left superior and inferior pulmonary vein antrum (LSPVA and LIPVA). On our 4D post-processing workstation (MIM Maestro™, MIM Software Inc.), maximum displacement of each point of interest from diastole to systole was measured in the mediolateral (ML), anteroposterior (AP), and superoinferior (SI) directions.


RESULTS
Median age of the enrolled patients was 60 years (range, 56-71 years). Within the CTVR, the mean displacements of the superior and inferior surrogates were 3 mm vs. 1 mm (p=0.002), 2 mm vs. 0 mm (p= 0.001), and 3 mm vs. 0 mm (p=0.00001), in the ML, AP, and SI directions, respectively. On the left, mean absolute displacements of the LSPVA vs. LIPVA were similar at 4 mm vs. 1 mm (p=0.0008), 2 mm vs. 0 mm (p= 0.001), and 3 mm vs. 1 mm (p=0.00001) in the ML, AP, and SI directions.


CONCLUSIONS
When isolated from breathing, cardiac contraction is associated with minimal inferior pulmonary veins motion and modest (1-6 mm) motion of the superior veins. Target deformation was thus of a magnitude similar or greater than target motion, limiting the potential gains of cardiac tracking. Optimal strategies for cardiac radiosurgery should thus either incorporate the generation of an internal target or cardiac gating. In either case, cardiac 4D DSCT would allow for personalized margin definition.
Department of Radiation Oncology, Centre hospitalier de l'université de Montréal (CHUM).
Houda
H
Bahig
Medical Imaging, Centre hospitalier de l'université de Montréal (CHUM).
Jacques
J
de Guise
Department of Radiation Oncology, Centre hospitalier de l'université de Montréal (CHUM).
Toni
T
Vu
Department of Radiology, Centre Hospitalier de l'Université de Montréal (CHUM).
Carl
C
Chartrand-Lefebvre
Department of Radiation Oncology, Centre hospitalier de l'université de Montréal (CHUM) - Hôpital Notre-Dame.
Danis
D
Blais
Department of Radiation Oncology, Centre hospitalier de l'université de Montréal (CHUM).
Martin
M
Lebeau
Department of Radiation Oncology, McMaster University-Juravinski Cancer Centre, Hamilton, ON.
Nhu-Tram
NT
Nguyen
Department of Oncology, Division of Radiation Oncology, McGill University Health Center ; Department of Radiology, Radiation Oncology and Nuclear Medicine, University of Montreal ; Department of Radiation Oncology, Centre hospitalier de l'université de Montréal (CHUM) ; Department of Oncology, Division of Radiation Oncology, McGill University Health Center.
David
D
Roberge
atrial fibrillation; cardiac; dual source ct; pulmonary vein isolation; radio-surgery