ok i will send some images,in inflammation size is increased,no mass affect,diffusely hypoechoic as compare to normal and on doppler just hyperemia seen no vessel prominent whereas in mass it is well circumscribed,mass affect present(compression of adjacent tubular structures or tissue) remaining part of the pancreas will be normal and if in head then signs of obstruction are more evident ,on doppler there will be prominent feeding vessels with RI more than 0.5.