Korean J Radiol.  2021 Apr;22(4):513-524. 10.3348/kjr.2020.0001.

Utility of Noncontrast Magnetic Resonance Angiography for Aneurysm Follow-Up and Detection of Endoleaks after Endovascular Aortic Repair

• Kawada H
• Goshima S
• Sakurai K
• Noda Y
• Kajita K
• Tanahashi Y
• Kawai N
• Ishida N
• Shimabukuro K
• Doi K
• Matsuo M

• KMID: 2514617
• DOI: http://doi.org/10.3348/kjr.2020.0001

Abstract

Objective
To assess the noncontrast two-dimensional single-shot balanced turbo-field-echo magnetic resonance angiography (b-TFE MRA) features of the abdominal aortic aneurysm (AAA) status following endovascular aneurysm repair (EVAR) and evaluate to detect endoleaks (ELs).
Materials and Methods
We examined four aortic stent-grafts in a phantom study to assess the degree of metallic artifacts. We enrolled 46 EVAR-treated patients with AAA and/or common iliac artery aneurysm who underwent both computed tomography angiography (CTA) and b-TFE MRA after EVAR. Vascular measurements on CTA and b-TFE MRA were compared, and signal intensity ratios (SIRs) of the aneurysmal sac were correlated with the size changes in the AAA after EVAR (AAA prognoses). Furthermore, we examined six feasible b-TFE MRA features for the assessment of ELs.
Results
There were robust intermodality (r = 0.92–0.99) correlations and interobserver (intraclass correlation coefficient = 0.97–0.99) agreement. No significant differences were noted between SIRs and aneurysm prognoses. Moreover, “mottled high-intensity” and “creeping high-intensity with the low-band rim” were recognized as significant imaging findings suspicious for the presence of ELs (p < 0.001), whereas “no signal black spot” and “layered high-intensity area” were determined as significant for the absence of ELs (p < 0.03). Based on the two positive features, sensitivity, specificity, and accuracy for the detection of ELs were 77.3%, 91.7%, and 84.8%, respectively. Furthermore, the k values (0.40–0.88) displayed moderate-toalmost perfect agreement.
Conclusion
Noncontrast MRA could be a promising imaging modality for ascertaining patient follow-up after EVAR.

Keyword

Abdominal aortic aneurysm; Stents; Stent-graft; Magnetic resonance imaging; Computed tomography; Endoleak; b-TFE MRA