As the arterial supply to the pancreas is complex, measuring single artery flow does not provide an accurate measure of perfusion. Furthermore, as some of the named branches supplying the arteries are secondary or tertiary branches of more major vessels, narrow arterial diameter precludes accurate radiological measurement. Arterial Spin Labelling (ASL) magnetic resonance imaging (MRI), on the other hand is a validated technique allowing accurate measurement of visceral perfusion.