Diagnosis and follow-up of Crohn disease (CD) often require invasive instrumental examinations, with a high risk of iatrogenic damage. Ultrasound (US) examin ation of bowel walls could be the first choice in managing patients with CD. We evaluated the role of tissue color power Doppler (CPD) and B-mode US with intra venous injection of contrast medium in the detection of disease activity. In our series, 52 patients with CD underwent US examination. Each study was compl eted with tissue CPD and US with intravenous injection of contrast medium (Sono Vue) to evaluate intestinal wall vascularization as an index of disease activity . We then compared our results with those from clinical and laboratory tests and follow up. Data from US examination with intravenous injection of Sono Vue par tly agreed with clinical and laboratory tests and CPD in disease activity evalua tion but were most useful in the follow up. Bowel US examination associated wit h CPD and in particular US contrast medium injection can be used to detect CD ac tivity and modulate therapy and follow up. Diagnosis and follow-up of Crohn disease (CD) often require invasive instrumental examinations, with a high risk of iatrogenic damage. Ultrasound (US) examintion of bowel walls could be the first choice in managing patients with CD. We evaluated the role of The tissue color power Doppler (CPD) and B-mode US with intra venous injection of contrast medium in the detection of disease activity. In our series, 52 patients with CD underwent US examination. Each study was complted with tissue CPD and US with intravenous We then compared our results with those from clinical and laboratory tests and follow up. Data from US examination with intravenous injection of Sono Vue par tly agreed with clinical and laboratory tests and CPD in disease activity evalua tion but were most useful in the follow up. Bowel US examination associated wit h CPD and in particular US contrast medium i njection can be used to detect CD ac tivity and modulate therapy and follow up.