Aortic dissection assessment by 4D phase-contrast MRI with hemodynamic parameters: the impact of stent type

Abstract

Background: To explore the diagnostic performance of 4-dimensional phase-contrast magnetic resonance imaging (4D PC-MRI) in evaluating aortic dissection in different clinical scenarios. Methods:The study group comprised 32 patients with a known aortic dissection who each underwent computed tomography angiography (CTA), and then 4D PC-MRI with a 1.5-T MR scanner. The 4D PC-MRI images were compared with the CTA images to evaluate the aortic size, branch identification, and iliac and femoral arterial access.Results: The patients were divided into three groups: (I) patients diagnosed with Type B aortic dissection but did not undergo intervention (n=8); (II) patients with residual aortic dissection after open repair of Type A dissection (n=7); (III) patients who underwent endovascular aortic repair with or without open surgery (n=17). Without radiation or contrast media injection, 4D PC-MRI provided similar aortic images for patients in Group 1 and most of those in Group 2. In Group 3, stainless steel stents affected image quality in three patients. High-quality 4D PC-MRI images were obtained for the remaining 14 patients in Group 3, who had non-stainless steel stents, and provided major aortic information comparable to that provided by CTA with contrast media. The hemodynamic parameters of true and false lumens were evaluated between three patients with Type B aortic dissections and three patients who underwent thoracic endovascular aortic repair for their aortic dissection. The stroke volume was higher in the true lumen of the patients with stentgrafts than in the patients with Type B aortic dissection without intervention. The regurgitant fraction, an indicator of nonlaminar flow, was higher in the false lumens than in the true lumens. All 32 patients in this study tolerated 4D PC-MRI without adverse events.Conclusions: 4D PC-MRI is radiation-and contrast media-free option for imaging aortic dissection. It not only provided images comparable in quality to those obtained with CTA but also provided information on hemodynamic parameters, including endoleak detection after thoracic endovascular aortic repair. 4D PC-MRI was safe and accurate in evaluating chronic Type B aortic dissection and residual aortic dissection after surgery for acute Type A aortic dissection. Therefore, it could be a potential tool in treating pathology in aortic dissection, especially for patients with malperfusion syndrome of visceral vessels and in young patients with renal function impairment. However, certain endograft materials, especially stainless steel, may prevent the further application of 4D PC-MRI and should be avoided.

Before and after Endovascular Aortic Repair in the Same Patients with Aortic Dissection: A Cohort Study of Four-Dimensional Phase-Contrast Magnetic Resonance Imaging

“…Researchers who conducted those studies did not identify significant limitations in reproducibility or repeatability that may affect measurements derived from 4D flow manners, which is consistent with our previous experience. We first applied 4D PC-MRI in a clinical setting; thus, 4D PC-MRI could provide similar information to that provided by CTA after open surgery for type A aortic dissections [17,46]. Moreover, 4D PC-MRI is also a reasonable imaging option for young patients and patients with poor renal function.…”

“…This analysis method that can quantify the phasecontrast parameters of the region of interest is also called quantitative PC-MRI (QFlow) [15]. Currently, the QFlow technique has been used in research related to cerebrospinal fluid, aorta, and peripheral vascular disease [16][17][18][19][20].…”

“…Our previous clinical study on 4D PC-MRI revealed that potential stent interference and stainless grafts should be avoided [17]. In this study, we used 4D PC-MRI to verify the impact of TEVAR in the same patients with aortic dissection, focusing on hemodynamic changes using the QFlow technique.…”

Using Non-Contrast MRA to Discriminate between Obstructive and Nonobstructive Venous Diseases of the Legs

“…A quantitative flow scan is routinely performed to determine the appropriate trigger delay times for systolic and diastolic triggering. All images are acquired without the use of a gadolinium contrast medium [6,9,[13][14][15]. In QFlow scans, multiple acquisitions occur within one cardiac cycle, resulting in multiple phases.…”

A Novel Tool for a Challenging Disease: Stasis Leg Ulcers Assessed Using QFlow in Triggered Angiography Noncontrast Enhanced Magnetic Resonance Imaging

“…QFlow technique can provide phase-contrast information of the measured region of interest. Currently, QFlow technique has been used in research related to cerebrospinal fluid, aorta, and peripheral vascular disease [ 8 , 9 , 10 , 11 ].…”