In the young population of CD patients, the ionizing radiation required for SBE limits the use of this technique for the follow-up of the disease. Moreover, SBFT and SBE examinations can often result in incomplete studies. In fact they cause sellekchem more patient discomfort compared with CT[25] and MRI[26], barium contrast can be poorly tolerated by children especially in severe and advanced disease and abdominal pain can limit compression preventing the adequate visualization of overlapping loops. ULTRASONOGRAPHY US has the distinct advantage of being widely available, inexpensive, non-invasive, radiation-free and relatively easy to perform[7,27]. Over the past few years, improvements in US equipment such as high-frequency transducers (7-12 MHz), combined with oral and intravenous (CE-US) contrast agents[28,29], have overcome some of the obstacles in bowel US that existed in the past, thus raising a great enthusiasm for its use in IBD children.
US can be considered a valuable tool in the preliminary diagnostic process of paediatric patients with suspected IBD, prior to further invasive tests[30,31]. Inflamed bowel can show both mural and extramural pathological changes. Bowel wall thickness is the most important US sign of IBD (Figure (Figure2),2), with different thickness values used as a threshold for a positive diagnosis in the various reports (from 1.5 mm to 3 mm in the terminal ileum and < 2 mm in the colon)[27,32-35]. Figure 2 Thickening of the bowel wall, 5 mm, (arrow) with wall layers preserved. The hyperechoic band corresponds to thickened submucosa.
The other US signs are altered echogenicity, loss of the normally visible stratification (Figure (Figure3),3), increased Colour-Doppler signal denoting hyperaemia (Figure (Figure4)4) and relative decrease or lack in peristalsis signifying some degree of stiffness[31]. Extra-mural findings include changes involving the surrounding mesentery, that appears thickened and hyperechoic and generally shows enlarged mesenteric lymph-nodes (Figure (Figure44)[30,36]. Figure 3 Transversal (A) and longitudinal (B) section of a thickened ileal loop due to Crohn��s disease. The ��target�� sign, corresponding to remarkable bowel wall thickness, is visible as a strong echogenic centre surrounded by a hypoechoic … Figure 4 Longitudinal view of the terminal ileum in a 13-year-old boy with active Crohn��s disease.
The bowel wall is thickened and shows increase in Color Doppler signals denoting inflammatory hyperemia (A). Note in (B) the fibrofatty proliferation of … Bowel US and ileocolonoscopy with histology have demonstrated an overall sensitivity of 74 and 88% and a specificity GSK-3 of 78 and 93%, respectively, in the detection of SB CD lesions[35,37]. The sensitivity of US in the detection of SB lesions is greater for those of the terminal ileum (approximately 90%-95%) than for those of the proximal SB (75%)[38].