Assessment of Blood Flow Pattern in a Ductus Arteriosus Aneurysm Using 4-Dimensional-Flow Cardiac Magnetic Resonance Imaging

A 72-year-old man was referred due to an aortic arch aneurysm found on computed tomography (CT) (Figure A). ECG-gated CT showed a patent ductus arteriosus (PDA) between the aorta (Ao) and pulmonary artery (PA), forming a saccular aneurysm (Figure B). Aortic angiography also showed a ductus arteriosus aneurysm (DAA) (Figure C). The patient underwent transcatheter closure of the PDA using an AmplatzerTM Vascular Plug II (Abbott, Chicago, IL, USA). Before the procedure, time-resolved 4-dimensional phase-contrast magnetic resonance imaging (4D-flow-MRI) was performed to evaluate the intra-aneurysm blood flow (Figure D–F, Supplementary Movie). Streamline and Pathline views revealed the internal helical blood flow, with both inflow and outflow occurring in a longitundinal direction. Wall shear stress (WSS) was maintained in the residual zone (Figure F, white arrowheads), but was low in the direct flow zone. We hypothesized that the helical blood flow and heterogeneous WSS contributed to the formation of the saccular aneurysm. 4D-flow-MRI has been used to assess the pathophysiology of various aneurysms,¹ and this is a rare case in which the blood flow in a DAA was visualized by 4D-flow-MRI.

Figure.

(A) Aortic arch aneurysm computed tomography (CT). ECG-gated CT (B) shows a patent ductus arteriosus (PDA) between the aorta (Ao) and pulmonary artery (PA), forming a saccular ductus arteriosus aneurysm (DAA), also visible on aortic angiography (C). (D–F) Time-resolved 4-dimensional phase-contrast magnetic resonance imaging (4D-flow-MRI) evaluation of the intra-aneurysm blood flow shows the internal helical blood flow on Streamline (D), while Pathline shows the blood flowing from the inflow trunk in a longitudinal direction (E, red arrow). The blood flow reverses at the bottom and is directed to the outflow tract (E, green arrow), while the residual blood churns helically from the middle to the apex (E, blue arrow). Wall shear stress is maintained in the residual zone (F, white arrowheads).

Informed Consent

Written informed consent was given by the patient.

Data Availability Statement

Not applicable.

Conflicts of Interest

None of the authors has any conflicts of interest or financial ties to disclose.

Supplementary Files

Supplementary Movie.

Please find supplementary file(s);

http://dx.doi.org/10.1253/circj.CJ-21-0208

Reference

• 1.   Natsume K, Shiiya N, Takehara Y, Sugiyama M, Satoh H, Yamashita K, et al. Characterizing saccular aortic arch aneurysms from the geometry-flow dynamics relationship. J Thorac Cardiovasc Surg 2017; 153: 1413–1420.