High resolution MRI of the vessel wall and atherosclerotic plaque is an area of increasing development.1 In this issue of J Neurol Neurosurg Psychiatry, Harloff and colleagues2 assessed the accuracy of 3 T MRI to detect aortic sources of cerebral embolism in comparison with transoesophagal echocardiography (TOE) (see page 540). They suggest that not only is MRI reliable in detecting aortic high risk plaques, but it is also potentially more accurate in investigating aortic segments that are not identified by TOE. Although there is little doubt that vessel MRI is a very promising technique, the authors’ enthusiasm needs to be qualified.

Firstly, as underlined by the …