Inflammatory activity in Crohn disease: ultrasound findings Vincenzo Migaleddu, 1 Emilio Quaia, 2 Domenico Scano, 1 Giuseppe Virgilio 1 1 Sardinian Mediterranean Imaging Research Group—no profit foundation, Via Gorizia n°11, 07100, Sassari Sardinia, Italy 2 Department of Radiology, Cattinara Hospital, University of Trieste, Trieste, Italy Abstract Improvements in the ultrasound examination of bowel disease have registered in the last years the introduction of new technologies regarding high frequency probes (US), highly sensitive color or power Doppler units (CD- US), and the development of new non-linear technolo- gies that optimize detection of contrast agents. Contrast- enhanced ultrasound (CE-US) most importantly in- creases the results in sonographic evaluation of Crohn disease inflammatory activity. CE-US has become an imaging modality routinely employed in the clinical practice for the evaluation of parenchymal organs due to the introduction of new generation microbubble contrast agents which persist in the bloodstream for several minutes after intravenous injection. The availability of high frequency dedicated contrast-specific US techniques provide accurate depiction of small bowel wall perfusion due to the extremely high sensitivity of non-linear signals produced by microbubble insonation. In CrohnÕs disease, CE-US may characterize the bowel wall thickness by differentiating fibrosis from edema and may grade the inflammatory disease activity by assessing the presence and distribution of vascularity within the layers of the bowel wall (submucosa alone or the entire bowel wall). Peri-intestinal inflammatory involvement can be also characterized. CE-US can provide prognostic data con- cerning clinical recurrence of the inflammatory disease and evaluate the efficacy of drugs treatments. Key words: Crohn disease—Inflammatory activity—Contrast media—Contrast-enhanced ultrasound—Color Doppler—Ultrasonography Follow-through barium examination, enteroclysis, endoscopy with biopsy and more recently wireless cap- sule endoscopy are considered the reference standards in the elective diagnostic assessment of CrohnÕs disease (CD) [1–7]. The principal drawback of these techniques is the exclusive evaluation of the internal surface of the gut without providing any direct data on the status of the small bowel wall. Computed Tomography (CT) and Magnetic Resonance (MR) enteroclysis are now consid- ered the reference imaging techniques for the mural and perivisceral status evaluation of the small bowel wall. Both techniques have improved the visualization of the small bowel wall and its vascularity [8–13]. Ultrasound (US) has become an alternative imaging technique to assess focal involvement of the small bowel due its high contrast and spatial resolution, and reduced invasiveness [14–17]. Special pulse generation (progra- mable wave generator) and compounding technology allow increased penetration, up to 12 cm depth, using a high frequency 8–14 MHz linear array transducer. B-Mode US is used in the morphologic assessment of the small bowel wall thickness, but does not provide any information about vascularity. Color and power Doppler (CD-US) can depict the parietal vessels of the small bowel wall even though the resolution for the slow flows is limited [18]. Contrast-enhanced ultrasound (CE-US) has become an imaging modality routinely employed in clinical practice for the parenchymal organs. This was due to the introduction of new generation microbubble contrast agents that persist in the bloodstream for several minutes after intravenous injection plus dedicated contrast-spe- cific US software. An innovative application of CE-US is the assessment of the small bowel wall and particularly the evaluation of inflammatory activity. According with the contrast-specific US techniques used, CE-US pro- vides accurate depiction of small bowel wall perfusion due to the extreme high sensitivity to the non-linear Correspondence to: Vincenzo Migaleddu; email: migaleddu@smirg.org ª Springer Science+Business Media, LLC 2007 Published online: 3 January 2008 Abdominal Imaging Abdom Imaging (2008) 33:589–597 DOI: 10.1007/s00261-007-9340-z