Diagnostic value and clinical utility of contrast enhanced ultrasound in intestinal diseases

Contrast enhanced ultrasound (CEUS) has recently gained increasing attention as it clearly improves the visualisation of perfusion in various tissues. The development of second generation contrast enhancing agents used in low-mechanical-index harmonic ultrasound has enabled real-time assessment of the microvascular circulation and quantification of bowel wall vascularity. For this review Medline was searched for clinical studies using CEUS to investigate the gastrointestinal tract. Many studies demonstrate that acute or chronic inflammation of the intestinal wall is accompanied by increased perfusion of the mesentery, which can be displayed semi-quantitatively using contrast enhanced ultrasound analyzing time intensity curves. In contrast, ischemia is characterized by hypoperfusion of the mesenteric arteries and the bowel wall. The most promising sonographic approach in assessing splanchnic arteries and the bowel wall is combining the analysis of superior and inferior mesenteric inflow by pulsed Doppler scanning (systolic and diastolic velocities, resistance index) with the end-organ vascularity by CEUS. CEUS at a preliminary stage has been described as clinically important in a variety of gastrointestinal disorders, particularly in patients with Crohn's disease. CEUS facilitates the detection of disease extent and activity, and its luminal and extraluminal complications.