Presurgical assessment of flow variability in an azygos vein aneurysm using 4D-flow MRI

Azygos vein aneurysm (AVA) is necessary to prevent pulmonary embolism due to the outflow of a thrombus or rupture of the aneurysm. However, there is no established modality to assess the properties of AVA. Time-resolved three-dimensional phase-contrast magnetic resonance imaging (4D-flow MRI) has been used to examine the hemodynamics in various fields. We report a case of AVA to evaluate the flow variability and adhesions of surrounding tissues using 4D-flow MRI. The findings of the study suggested aneurysm turbulence and the absence of thrombi. The cine image, which showed a sliding wall synchronized to the heartbeat, indicated no adhesion to the superior vena cava. Based on these results, the thoracoscopic approach was deemed possible preoperatively. Thoracoscopic AVA resection was performed, and the postoperative course was uneventful. This study documented the utility of 4D-flow MRI for a detailed evaluation of AVA.