Common and Uncommon Applications of Bowel Ultrasound With Pathologic Correlation in Children

Abstract

Ultrasound is a useful tool for the evaluation of inflammatory bowel disease and many other bowel diseases. Radiologists must become familiar with the full potential of ultrasound in the evaluation of the bowel in children because the need for alternative radiation-free imaging techniques continues to grow.

Ultrasound features of pediatric Crohn disease: a guide for case interpretation

“…The thickness of each layer of the bowel does not correspond to the actual anatomical thickness since the sonographic image results from echoes secondary to acoustic interfaces rather than the structure itself [16]. Normal small bowel wall thickness is less than 2.5 mm and normal colonic wall thickness is less than 2 mm in children [6,13]. In our practice, any segment of bowel with a wall thickness of 3 mm or greater is considered abnormal.…”

“…These include operator skills variability, lack of an acoustic window due to bowel gas, large body habitus and distorted anatomy in postoperative patients or postoperative patients with ostomies [6,13]. Practically, performing a bowel US with adequate compression in an obese patient is challenging.…”

“…While simultaneously compressing the bowel, anteriorly with the transducer, a hand is placed underneath the patient to apply posterior manual pressure in the same area [6,15]. At our institution, we begin with the highest frequency linear transducer we have available (12)(13)(14)(15) and then decrease the transducer frequency as needed depending on the body habitus of the patient to evaluate the deeper pelvis to look for fluid collections or abscesses [3,11,16].…”

“…Each bowel segment is scanned in the transverse and longitudinal planes and evaluated with color Doppler to assess hyperemia. Color Doppler should be performed at a low pulse repetition frequency with a low wall filter, low velocity scale and highest Doppler gain [6,17,18]. Extra-intestinal structures such as the mesentery are also evaluated with gray-scale and color Doppler simultaneously with each bowel segment [6].…”

“…However, published literature describes no significant difference in the diagnostic accuracy of the evaluation of IBD with MRE, multidetector CT and US [5]. US is used widely in Europe and Asia to assess the bowel in Crohn disease, but only recently is being used in pediatric radiology practices in the United States [6][7][8]. US is emerging as a practical alternative to MRE and CTE in the evaluation of known Crohn disease and in its initial diagnosis.…”