Artefactual limitations of magnetic resonance imaging in the diagnosis of recoarctation of the aorta

A 5-month-old boy was found coincidentally to have signs of coarctation of the aorta with hypertension and absent femoral pulses. Echocardiography revealed a severe coarctation just distal to the left subclavian artery. The aortic valve was bicuspid and mildly stenotic. He underwent end-to-end anastomotic repair at surgery. Thirteen years later he had imaging of the aorta with MRI because of systemic hypertension. MRI of the aorta showed a residual coarctation with an estimated gradient of 64 mm Hg (fig 1). Figure 1 (A) The transverse aorta is small and there is an obvious coarctation. (B) Angiography showed only insignificant narrowing of the aorta. Recoarctation, residual stenosis, persistence of aortic arch hypoplasia, and false aneurysm at the level of surgical repair are well described on MRI.1 False-positive results occurred in our patient due to the metal surgical clips in the close vicinity of the coarctation repair site degrading the image. We had obviously underestimated the degree to which this artefact can occur and wish to share our experience to avoid repetition of such mistakes. This report urges caution in the interpretation of MRI images of the aortic arch in the context of previous surgery.