Pedal artery imaging--a comparison of selective digital subtraction angiography, contrast enhanced magnetic resonance angiography and duplex ultrasound.

Objective: to evaluate selective digital subtraction angiography (DSA), contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultrasound (duplex) in preoperative pedal artery imaging.

Material And Methods: DSA, CE-MRA and duplex were studied prospectively in 37 patients suffering from critical leg ischaemia. Two radiologists independently reviewed both the CE-MRA and DSA images. The pedal vessels were scored on a scale from 0 to III (0=vessel not visualised, I=vessel faintly visualised, II=stenosis >50%, III=vessel without relevant stenosis). Duplex ultrasound was performed by an angiologist blind to both the DSA and MRA findings and the pedal arteries were scored 0-III according to their diameter. Each examiner named the pedal artery best suitable for bypass surgery. Agreement in artery assessment was expressed as kappa values. Patency of the bypass at 30 days was used as validation of the artery's suitability as the run-off vessel.

Results: interobserver agreement for DSA (weighted Kappa 0.63, CI 0.53-0.73 and CE-MRA (weighted kappa 0.60, CI 0.5-0.7) was moderate to substantial. CE-MRA depicted significantly more vascular segments than DSA (p congruent with 0.0001).In the prediction of the distal outflow vessel duplex and CE-MRA proved to be superior to DSA.

Conclusion: because of the moderate inter-observer agreement it may be questionable to regard selective DSA as gold standard imaging procedure in preoperative pedal artery imaging. CE-MRA and duplex are very helpful in assessing the pedal artery morphology and should be used if selective DSA does not sufficiently depict the pedal vasculature.