Free-breathing, blood-flow-independent, three-dimensional relaxation-enhanced angiography without contrast and triggering (REACT) for aorta measurement and diagnosis in patients with aortic disease: a comparison with computed tomography angiography

Abstract

Background

Patients with aortic diseases require precise quantitative assessment and long-term regular follow-up monitoring. Computed tomography angiography (CTA) is widely used for evaluation; however, its application is limited by ionizing radiation exposure and iodinated contrast administration. This study aimed to evaluate the feasibility and accuracy of a novel technique—free-breathing, blood-flow-independent, three-dimensional (3D), relaxation-enhanced angiography without contrast and triggering (REACT)—for the assessment of aortic disease as an alternative to CTA.

Methods

A total of 101 patients were included in this single-center prospective study, comprising 54 patients with aortic aneurysm (AA), 30 patients with aortic dissection (AD), and 17 patients who had previously undergone endovascular aortic repair (EVAR). All the patients underwent both REACT and CTA examinations. An intraindividual assessment was performed by measuring aortic diameters at 11 levels. Overall image quality was evaluated independently by three readers using a 5-point scale. Additionally, for AA, AD, and EVAR, diagnostic confidence using different criteria was assessed. Differences and consistency between REACT and CTA were analyzed.

Results

There was no significant difference in aortic diameter assessment between REACT and CTA (all P>0.05). REACT had lower overall image quality than CTA (3.77±0.52 vs. 4.29±0.57, P<0.001). REACT showed comparable diagnostic confidence to CTA for the assessment of aneurysm morphology and intraluminal thrombus (ILT). However, REACT showed lower diagnostic confidence than CTA for AD and EVAR evaluation. Interobserver consistency was high for the two imaging methods in subjective scoring (range, 0.67–0.88).

Conclusions

REACT can accurately display aortic morphology and is valuable for diagnosing aortic disease, especially AA. It could serve as an alternative to CTA for repeated aortic imaging.

Introduction

With population aging, the incidence of aortic disease has increased, and studies have reported a global mortality rate of 2.78 per 100,000 people (1,2). Patients with aortic disease usually require life-long surveillance. As outlined in the 2022 American College of Cardiology/American Heart Association Guideline for the Diagnosis and Management of Aortic Disease (3) and the 2024 European Association for Cardio-Thoracic Surgery/Society of Thoracic Surgeons guidelines for diagnosing and treating acute and chronic syndromes of the aortic organ (4), the recommended surveillance imaging frequency for abdominal aortic aneurysm (AA) ranges from every 6 months to 3 years, depending on aneurysm size. In patients with treated acute aortic dissection (AD), surveillance imaging is recommended at 1, 6, and 12 months, and then, if stable, annually thereafter. Regular aortic imaging is the most important aspect of surveillance, in addition to clinical evaluation and reassessment of the patient’s drug therapy and treatment goals (3).

Computed tomography (CT) plays an important role in the diagnosis and management of aortic disease. Its advantages include rapid image acquisition, high spatial and temporal resolution, and the ability to obtain a complete three-dimensional (3D) dataset of the entire aorta, resulting in its wide use in clinical practice. Current guidelines (3) recommend CT angiography (CTA) as the initial imaging modality in patients with suspected aortic disease. However, its use is limited by ionizing radiation exposure and iodinated contrast administration, restricting its use in certain populations, such as patients with iodine contrast allergies, those with renal insufficiency (5), and pregnant or potentially pregnant patients (6). Ultrasound is an important technique for the screening and follow-up of aortic disease because it is inexpressive and convenient. However, it can only display the proximal aorta and descending aorta (but not the aortic arch), and it is highly operator dependent (7).

The ability of magnetic resonance angiography (MRA) to distinguish between blood flow and the vessel wall, together with breath-hold contrast-enhanced MRA allowing rapid image acquisition, has led to it widespread used in aortic disease (8). A novel imaging technique—free-breathing, blood-flow-independent, 3D relaxation-enhanced angiography without contrast and triggering (REACT)—which requires neither exogenous gadolinium-based contrast agent nor electrocardiographic (ECG) triggering, has recently been introduced. It has demonstrated clinical value in evaluating the pulmonary vasculature (9,10), thoracic aorta (11,12), abdominal arteries (13), extracranial arteries (14-16), and pelvic veins (17), as well as in planning for transcatheter aortic valve implantation (TAVI) (18) and vascular assessment after renal transplantation (19).

REACT uses a 3D dual-echo Dixon acquisition, integrating T2 preparation and a non-selective inversion recovery (IR) pulse to enhance contrast and suppress background tissue signals. The Dixon acquisition method employs an improved generalized two-point solution with flexible echo times (TEs), enabling effective water-fat separation. Additionally, magnetization preparation pulses are used to suppress signals from short T2 tissues, while the IR pulse enhances vascular visualization by reducing signals from short-to-intermediate T1 and T2 tissues (20). REACT provides high blood-tissue contrast over a large field of view (FOV), enabling 3D isotropic imaging without triggering. However, to date, no studies have evaluated the use of REACT in the diagnosis of AA or AD, nor has the feasibility of REACT been evaluated in patients who have undergone endovascular aortic repair (EVAR).

Therefore, this study aimed to assess the feasibility and accuracy of REACT in aortic imaging by comparing aortic diameters measured on REACT and CTA images. Additionally, the reliability of REACT in the diagnosis of AA, AD, and EVAR was assessed multi-dimensionally using a subjective diagnostic scoring system. We present this article in accordance with the STARD reporting checklist (available at https://qims.amegroups.com/article/view/10.21037/qims-2025-1-2650/rc).

Methods

Study population

The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Ethics Committee on Biomedical Research, West China Hospital of Sichuan University (approval No. 2021-1171). Informed consent was obtained from all the patients.

Patients with aortic diseases at West China Hospital of Sichuan University between August 2023 and September 2024 were included in the study. The inclusion criteria were as follows: (I) the presence of AA, AD, or prior EVAR; (II) an interval of less than 1 month between CTA and magnetic resonance imaging (MRI) examinations; and (III) age >18 years. The exclusion criteria were as follows: (I) contraindications to MRI and CTA; and/or (II) the presence of severe motion artifacts in images.

Imaging protocol

The MRI examinations were performed on a 3T clinical scanner (Ingenia, Philips Healthcare, Amsterdam, The Netherlands) equipped with a 32-channel phased array body coil. The REACT protocol was a 3D Cartesian, spoiled gradient echo acquisition with diaphragm navigator, and without exogenous gadolinium contrast administration or ECG triggering. The imaging parameters were set to an acquired resolution of 1.5×1.5×1.5 mm³ and a reconstructed resolution of 0.625×0.625×0.75 mm³. The FOV was 380×320×150 mm³, covering the entire aorta from the aortic arch to the common iliac arteries. A flip angle of 15° was used, with a repetition time of 4.3 ms, and a TE of 1.41 ms. The T2 preparation time was 50 ms with four refocusing pulses. Further, a compressed sensing-sensitivity encoding (CS-SENSE) acceleration factor of six was applied, resulting in a nominal scan time of 4 min 20 s. This combination of parameters aimed to optimize image quality while minimizing scan time. Images were reconstructed inline by the scanner and were immediately available for review.

The CT examinations were performed using a multidetector CT scanner (Flash, Siemens Healthcare, Munich, Germany). CTA imaging covered the entire aorta from the carotid bifurcation to the pelvic floor. The scanning parameters were as follows: a tube voltage of 120 kV, automated adjusted tube current, and a slice thickness of 0.6 mm. Each patient received an injection of 70 mL of iomeprol (400 mgI/mL) at a flow rate of 3–4 mL/s, followed by 40 mL of saline solution, using a dual-syringe power injector (Stellant-Dual Flow; Medrad, Pittsburgh, PA, USA). Bolus tracking was performed at the descending aorta with a threshold of 100 Hounsfield units (HU). Patients were positioned supine with both arms raised. Images were reconstructed with a slice thickness of 1 mm and an increment of 1 mm. The total scan time for the CTA acquisition was approximately 30–50 seconds, including contrast injection.

Aorta measurement

For all the analyses in this study, water-only images generated by REACT were used. The images underwent post-processing on a workstation (IntelliSpace Portal, Philips Healthcare, Best, The Netherlands) and presented randomly to W.Z. and X.L., each with more than 3 years of experience in angiography. The radiologists were blinded to each other’s assessments and the clinical radiology reports. Aortic measurements were performed on 3D datasets using double-oblique angulations perpendicular to the vessel’s long axis, and the maximum diameter of each plane was recorded. The inner edge-to-inner edge method was used to measure diameters at 11 pre-defined levels according to the guidelines (3,4), as detailed in Table 1.

Table 1. Aortic diameter measurements at 11 locations.

Locations	Identification
Sinotubular junction	At the transition of the aortic sinus to the more tubular ascending aorta
Mid ascending aorta	Halfway between the sinotubular junction and the proximal aortic arch
Proximal aortic arch	Proximal to the origin of the brachiocephalic artery
Mid aortic arch	Between the left common carotid artery and the subclavian arteries
Proximal descending aorta	Approximately 2 cm distal to the left subclavian artery
Mid descending aorta	The midpoint between the proximal descending aorta and the aorta at the diaphragm level
Aorta at diaphragm	2 cm above the celiac trunk
Abdominal aorta	Infrarenal abdominal aorta, 1 cm distal to the renal arteries
Right before aortic bifurcation	2 cm above the bifurcation
Left common iliac artery	The midpoint of the common iliac artery
Right common iliac artery	The midpoint of the common iliac artery

Image quality

For all the patients, overall image quality was assessed using a 5-point Likert scale (1, unable to distinguish the aorta; 2, barely able to see the aorta; 3, average quality as encountered in clinical practice; 4, good quality with a few artifacts; 5, excellent quality without artifacts) by three readers (W.Z. and X.L., two radiologists with experience in angiography, and C.W., a vascular surgeon with 6 years of experience in aortic diseases).

Diagnostic confidence

Diagnostic confidence was assessed using a 5-point Likert scale (1, non-diagnostic, inadequate for diagnosis; 2, poor, suboptimal for diagnosis; 3, fair, acceptable for diagnosis; 4, good, suitable for confident diagnosis; 5, excellent, providing highly confident diagnosis). The diagnostic confidence scores were also evaluated by three readers (as described above).

In addition, diagnostic confidence was assessed across several dimensions for patients with different aortic diseases. For patients with AA, diagnostic confidence regarding aneurysm morphology and intraluminal thrombus (ILT) was evaluated. For patients with AD, diagnostic confidence in identifying tears, the extent of dissection, true and false lumen differentiation, and branch vessel involvement was evaluated. For patients who had undergone EVAR, the stent graft was assessed.

Statistical analysis

Prism (version 9; GraphPad Software, Inc., San Diego, CA, USA) was used for the statistical analysis. Normally distributed continuous variables are presented as mean ± standard deviation (SD), while non-normally distributed continuous variables are expressed as median with interquartile range (IQR). The Shapiro-Wilk test was used to evaluate data normality. The average of the aortic diameter measurements from the two readers and the averaged subjective scores from the three readers were used for the analysis. To assess differences in the aortic measurements between REACT and CTA, either the paired t-test or Wilcoxon test was used as appropriate. Additionally, a Bland-Altman analysis was performed to determine the consistency of the aortic assessments between REACT and CTA. The Wilcoxon rank-sum test was used to compare overall image quality and diagnostic confidence scores between the two imaging modalities. To assess the consistency of the aortic diameter measurements between two observers, intraclass correlation coefficient (ICC) values were calculated. To evaluate interobserver consistency on image quality and diagnostic confidence scores among three readers, Kendall’s coefficient of concordance (Kendall’s W) was used. The levels of consistency were classified as follows: almost perfect (0.81–1.00), substantial (0.61–0.80), moderate (0.41–0.60), fair (0.21–0.40), or none to slight (0.01–0.20).

Results

Patients

A total of 116 patients were recruited for this study; however, 11 patients were excluded because the interval between the CTA and REACT examinations was more than 1 month, and four patients were excluded because of incomplete coverage of the target aortic volume. Thus, a total of 101 patients (85 male; 61.46±13.01 years) were included in the study, comprising 54 patients (49 male; 64.17±12.17 years) with AA, 30 patients with AD, and 17 patients (14 male; 64.36±12.30 years) who had previously undergone EVAR. For further information on the study workflow, see Figure 1.

Figure 1.

Workflow for inclusion and exclusion of patients. CTA, computed tomography angiography; MRA, magnetic resonance angiography; REACT, relaxation-enhanced angiography without contrast and triggering.

Diameter measurements

Table 1 provides the aortic diameter measurements obtained using REACT and CTA. There were no significant differences in the aortic diameters at the 11 pre-defined levels between the two imaging modalities (all P>0.05). The Bland-Altman results showed consistency between REACT and CTA across the 11 aortic levels (Table 1, Figure 2). The mean bias was approximately 0.04 cm, with the maximum difference within 0.5 cm, demonstrating good consistency between the two methods. Additionally, no significant differences were observed in aneurysm anterior-posterior and left-right diameters or ILT thickness between REACT and CTA (all P>0.05). Detailed results are provided in Table 2.

Figure 2.

Bland-Altman analysis comparing the diameters of the 11 aortic planes measured by REACT and CTA; the blue line represents the mean bias; the black dashed lines represent the 95% limits of agreement. CTA, computed tomography angiography; REACT, relaxation-enhanced angiography without contrast and triggering.

Table 2. Results of diameter assessment using REACT and CTA at 11 planes.

Locations	REACT	CTA	Bias	95% limits of agreement	P value
Sinotubular junction (cm)	3.23±0.38	3.20±0.40	−0.031	−0.39, 0.33	0.121
Mid ascending aorta (cm)	3.61±0.47	3.60±0.50	−0.008	−0.44, 0.42	0.740
Proximal aortic arch (cm)	3.44±0.44	3.44±0.45	0.006	−0.32, 0.33	0.758
Mid aortic arch (cm)	2.97±0.43	2.99±0.42	0.014	−0.32, 0.35	0.452
Proximal descending aorta (cm)	3.08 (2.74–3.30)	3.11 (2.78–3.41)	0.031	−0.32, 0.38	0.079
Mid descending aorta (cm)	2.75 (2.40–2.82)	2.78 (2.44–2.94)	0.031	−0.33, 0.40	0.141
Aorta at diaphragm (cm)	2.78 (2.31–2.85)	2.80 (2.33–3.03)	0.024	−0.26, 0.31	0.057
Abdominal aorta (cm)	2.12 (1.70–2.42)	2.14 (1.76–2.37)	0.018	−0.23, 0.26	0.390
Right before aortic bifurcation (cm)	2.61 (1.90–3.31)	2.64 (1.98–3.23)	0.027	−0.27, 0.32	0.102
Left common iliac artery (cm)	1.55 (1.12–1.67)	1.59 (1.12–1.74)	0.034	−0.25, 0.32	0.058
Right common iliac artery (cm)	1.49 (1.09–1.81)	1.53 (1.13–1.76)	0.036	−0.25, 0.32	0.056
AA morphology
Anterior-posterior diameter (cm)	4.77 (3.99–5.25)	4.80 (4.20–5.37)	0.030	−0.35, 0.41	0.403
Left-right diameters (cm)	4.99 (4.22–5.58)	4.99 (4.30–5.30)	−0.003	−0.52, 0.52	0.636
Thickness of ILT (cm)	1.56 (0.62–2.47)	1.57 (0.71–2.08)	0.013	−0.50, 0.53	0.075

Data are presented as mean ± SD or median (IQR). Three parameters of AA were assessed only on patients with AA. Bias and 95% limits of agreement were analyzed using Bland-Altman analysis. P values were calculated using a paired t-test or a Wilcoxon test according to the normality of the data. AA, aortic aneurysm; CTA, computed tomography angiography; ILT, intraluminal thrombus; IQR, interquartile range; REACT, relaxation-enhanced angiography without contrast and triggering; SD, standard deviation.

Overall image quality and diagnostic confidence

The subjective image quality of REACT and CTA was also evaluated. The average scores from the three readers were used for the analysis. Overall image quality was lower for REACT than for CTA (3.77±0.52 vs. 4.29±0.57, P<0.001). The diagnostic value of REACT differed according to the aortic disease. In patients with AA, no significant differences in the diagnostic confidence scores were observed between the two groups for the assessment of aneurysm morphology (4.94±0.23 vs. 4.96±0.19, P>0.99) and ILT (4.82±0.39 vs. 4.94±0.23, P=0.065). Conversely, in patients with AD, REACT had lower diagnostic confidence scores than CTA across all four evaluated dimensions (all P<0.001). Among these, the lowest diagnostic confidence score for REACT was observed in the diagnosis of tears (3.67±1.12 vs. 4.60±0.67, P<0.001). Similarly, in patients who had undergone EVAR, REACT had lower scores than CTA (4.35±0.70 vs. 4.94±0.24, P=0.018).

The image quality evaluation results are provided in Table 3. Figures 3-5 show representative REACT and CTA images for patients with AA, AD, and EVAR, respectively.

Table 3. Results of subjective scoring for REACT and CTA.

Evaluation index	REACT	CTA	P value
Overall image quality	3.77±0.52	4.29±0.57	<0.001
Abdominal AA
Aneurysm morphology	4.94±0.23	4.96±0.19	>0.99
ILT	4.82±0.39	4.94±0.23	0.065
AD
Tears	3.67±1.12	4.60±0.67	<0.001
Range of AD	4.33±0.88	4.97±0.18	<0.001
True and false lumen	4.53±0.57	4.97±0.18	<0.001
Branch vessel involvement	4.47±0.63	5.00±0.00	<0.001
Aortic stent
Stent morphology	4.35±0.70	4.94±0.24	0.018

Data are presented as mean ± SD. Overall image quality and diagnostic confidence scores for three aortic diseases were analyzed. AA, aortic aneurysm; AD, aortic dissection; CTA, computed tomography angiography; ILT, intraluminal thrombus; REACT, relaxation-enhanced angiography without contrast and triggering; SD, standard deviation.

Figure 3.

Coronal and axial images of a patient with an abdominal AA (yellow arrows). REACT (A,C) showed the morphology of the aneurysm as clearly as CTA (B,D). The intraluminal thrombosis (blue arrows) was also detected on both methods of imaging. AA, aortic aneurysm; CTA, computed tomography angiography; REACT, relaxation-enhanced angiography without contrast and triggering.

Figure 4.

Multiplanar reformatted images of a patient with AD. The largest tear at the aortic arch was clearly displayed on both REACT (A) and CTA (B). The tear near the renal artery was visible on both REACT (C) and CTA (D) but somewhat less clear. The small tear at the abdominal aorta was difficult to detect on REACT (E) compared with CTA (F). Blue arrows show the tears of AD. AD, aortic dissection; CTA, computed tomography angiography; REACT, relaxation-enhanced angiography without contrast and triggering.

Figure 5.

Multiplanar reformatted images of a patient after endovascular repair. The stent morphology was displayed on both REACT (A) and CTA (B). Blue arrows show the start of the stent. CTA, computed tomography angiography; REACT, relaxation-enhanced angiography without contrast and triggering.

Interobserver consistency

Interobserver consistency for the aortic diameter measurements was excellent, with ICCs ranging from 0.92 to 0.99 between the two readers. Interobserver consistency among the three readers for overall image quality and diagnostic confidence scores is presented in Table 4. The three readers demonstrated almost perfect consistency for diagnostic confidence scores in AA and EVAR (range, 0.81–0.88), while the consistency for diagnostic confidence scores was substantial in AD (range, 0.67–0.86).

Table 4. Interobserver consistency for overall image quality and diagnostic confidence scores in REACT and CTA.

Evaluation index	REACT	CTA
Overall image quality	0.81	0.90
Aneurysm morphology	0.84	0.87
ILT	0.88	0.86
Tears	0.71	0.77
Range of AD	0.78	0.92
True and false lumen	0.83	0.88
Branch vessel involvement	0.86	0.86
Stent morphology	0.82	0.89

Data are presented as Kendall’s coefficient of concordance. AD, aortic dissection; CTA, computed tomography angiography; ILT, intraluminal thrombus; REACT, relaxation-enhanced angiography without contrast and triggering.

Discussion

This study evaluated the feasibility and diagnostic value of REACT in patients with aortic diseases, including in patients with AA, AD, and EVAR, using CTA as the gold standard. REACT demonstrated good feasibility, and showed good consistency with CTA for vessel diameter measurements. Although the image quality of REACT was inferior to that of CTA, it did not limit the diagnosis of the diseases. Notably, in patients with AA, REACT showed excellent diagnostic value compared with CTA.

Key decisions regarding the management of aortic disease largely depend on aortic size (3). CTA has long been considered the gold standard for the diagnosis of aortic disease because of its speed, high spatial resolution, and ease of 3D post-processing. In the present study, REACT also enabled 3D imaging of the aorta and demonstrated good consistency with CTA for diameter measurements across multiple planes of the aorta. The results showed that the diameter measurements were accurate across multiple parts of the aorta. Similar results have been reported in previous studies. Notably, Wang et al. used REACT to assess aortic valve and the entire aorta, from the ascending aorta to the common iliac arteries, for preprocedural planning for TAVI, and reported good consistency between REACT and CTA in the display of cardiovascular structures (18). Zeilinger et al. compared the aortic diameters of patients with aortic disease between REACT and CTA at 11 levels and found no significant differences (21).

In the subjective scoring of overall image quality, the results showed that the overall image quality of REACT was lower than that of CTA, especially in the diaphragm area, where motion artifacts from free breathing and heartbeat blurred images of the thoracic aorta. However, when measuring the aortic diameter, these artifacts barely affected the visualization of the inner wall of the aorta. Conversely, Zeilinger et al. (21) found that during the subjective evaluation of each aortic level, REACT was able to achieve image quality similar to that of CTA. However, a typical MRA navigator artifact was observed in the right half of the coronal image. Additionally, several studies (10,14,15,17,22,23) have compared REACT with contrast-enhanced MRA, reporting higher image quality and diagnostic confidence with REACT compared to contrast-enhanced MRA. For example, Gietzen et al. (23) reported that REACT showed high sensitivity and specificity for detecting ≥50% stenosis of the internal carotid artery. Similarly, Isaak et al. (10) found that REACT provided better image quality than contrast-enhanced MRA at the ascending aorta and coronary roots.

In addition, REACT demonstrated excellent diagnostic efficiency in AA, providing both radiologists and clinical surgeons with a high level of diagnostic confidence, especially in determining AA morphology and ILT. In general, ILT is difficult to detect on non-enhanced CT. Contrast-enhanced CTA can differentiate thrombus from blood flow; however, REACT can detect ILT without the need for contrast agent administration. Moreover, stratification in some of the larger ILTs was observed in this study. This may be due to the difference in blood content inside the thrombus. This also suggests that REACT may provide important information in the future study of ILT.

REACT had low diagnostic confidence scores for AD. There may be several reasons for this. First, the scanning range was limited. In some patients, the tears extended to the distal common iliac artery. Due to the limited length of the coil and magnet, some distal dissections fell outside the scanning range, affecting diagnostic confidence. Wang et al. (18) addressed this issue by scanning the entire aorta in three slabs. Second, the detection of some small ruptures remains challenging, making diagnosis difficult. However, for most patients with AD, REACT still had diagnostic value. Although the diagnostic confidence score was lower than that of CTA, it did not affect the differentiation between true and false lumens, as well as branch involvement, and some larger ruptures were easily recognized.

In this study, we found that REACT was not as effective as CTA in visualizing stent morphology due to artifacts, such as low internal flow signal in the aortic segment with the stent. However, in some patients, REACT was able to partially detect endoleaks (Figure 6). Almansour et al. (24) found golden-angle radial sparse parallel MRA had a high accuracy in the diagnosis of endoleaks, especially in type II endoleaks, with fewer image motion artifacts. Although non-enhanced MRA has rarely been used to diagnose endoleaks, Almansour et al.’s findings may lead to further research in this area (24,25). Gietzen et al. also showed the feasibility of REACT-MRA in patients after aortic root surgery, further supporting its potential as a non-contrast alternative for post-surgical surveillance (26).

Figure 6.

Axial (A) and coronal (B) REACT images of a patient after endovascular repair. Blue arrows show the endoleak in this patient. REACT, relaxation-enhanced angiography without contrast and triggering.

The acquisition time of REACT was longer than that of CTA. In this study, the CS-SENSE technique was used (a factor of 6) to achieve accelerated acquisition with a scan time of 4 min 20 s. CS-SENSE (27,28) uses SENSE for parallel imaging and combines it with compressed sensing to achieve fast imaging. Wang et al. (18) used CS-SENSE (a factor of 3) to perform fast large-FOV scanning, completing three slabs with a FOV of 350×394×120 mm³ in 6 min. Gietzen et al. (23) used REACT accelerated by CS (a factor of 7) in patients with acute ischemic stroke and a scan time of only 1 min 22 s. Additionally, Pennig et al. (11), using CS-accelerated REACT to image the thoracic aorta, reported a scan time of approximately 6 min 34 s. With the advancement of magnetic resonance undersampling technology and the integration of deep learning–based reconstruction algorithms, the scan time of REACT is expected to decrease further, potentially enabling fast acquisitions while maintaining high image quality (29,30).

This study had several limitations. First, it was a single-center study. Although the overall cohort size was adequate, the subgroup sample sizes were relatively small. Second, readers could clearly distinguish between CTA and MRA images when evaluating diagnostic confidence scores, which may have introduced bias, as readers are generally more familiar with CTA images. Third, the aortic diameter measurements were performed manually. Despite the use of clear anatomical marks, slight differences remained. Finally, REACT demonstrated initial value in the diagnosis of endoleaks; however, this research could not be extended further due to the limited number of patients. In future studies, we intend to further evaluate the ability of REACT to detect and differentiate endoleaks.

Conclusions

Overall, REACT demonstrated high accuracy in depicting aortic morphology and had some diagnostic value in aortic disease. It is recommended as an imaging tool for the diagnosis and follow-up of patients with AA. For patients with AD and EVAR, REACT, which is free of ionizing radiation and iodine contrast, may be considered as an alternative to CTA.

Supplementary

The article’s supplementary files as

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Ethics Committee on Biomedical Research, West China Hospital of Sichuan University (approval No. 2021-1171). Informed consent was taken from all the patients.

Data Sharing Statement

Available at https://qims.amegroups.com/article/view/10.21037/qims-2025-1-2650/dss

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DOI: 10.21037/qims-2025-1-2650