• flash pulmonary oedema
• multislice computed tomography
• renal artery stenosis

A subgroup of hypertensive patients, with preserved left ventricular function, are susceptible to recurrent episodes of sudden non-ischaemic pulmonary oedema caused by severe (usually bilateral) renal artery stenosis. Renal revascularisation may prevent the occurrence of “flash” pulmonary oedema. More than 70% of patients treated with percutaneous renal revascularisation are free from pulmonary oedema at 12 month follow up.^1,2 Although patient selection for renal revascularisation remains controversial, it is generally accepted that patients with recurrent flash pulmonary oedema should at least be considered for intervention.³ Diagnosis requires non-invasive imaging of the renal arteries and this may be achieved with Doppler ultrasonography. However the failure rate is high and it is not therefore a reliable clinical technique.⁴ Magnetic resonance or computed tomography (CT) angiography are possible alternatives, and both provide additional imaging of the abdominal aorta and three dimensional visualisation. Magnetic resonance imaging is generally the less available of the two options. Helical, single slice, CT has been evaluated in comparison to invasive renal angiography, and the sensitivity and specificity for the detection of ⩾ 70% stenoses, at all sites, has been estimated at up to 92% and 83%, respectively (using maximum intensity projection).⁵ Multislice CT, which …