Técnicas seccionales de imagen en la enfermedad de Crohn: ecografía, tomografía computarizada y resonancia magnética

Ultrasound findings of Crohn's disease: correlation with MR enterography

Crohn's disease is a chronic inflammatory bowel disease characterized by periods of relative inactivity alternating with acute flare-ups. Imaging techniques play a fundamental role in the diagnosis and follow-up of Crohn's disease, providing information on the extent of disease, disease activity, and the presence of extramural complications. Because of the frequent re-evaluation required by the relapsing nature of Crohn's disease and the relative young age at which most patients are diagnosed, techniques that use ionizing radiation are best avoided in monitoring this population. Thus, magnetic resonance enterography (MRE) and ultrasonography (US) are the preferable techniques. Various studies have demonstrated that US is accurate in assessing the gut. Despite some clear advantages over MRE, US has long been underused in the evaluation of intestinal disease. This review presents an overview of the main imaging findings in Crohn's disease, correlating representative US images with MRE and surgical pathology specimens. We conclude that US reliably depicts both bowel-related and mesenteric features of Crohn's disease and US findings correlate strongly with MRE findings.

Usefulness of intestinal ultrasound in inflammatory bowel disease

Imaging techniques play a fundamental role in the initial diagnosis and follow-up of inflammatory bowel disease. Intestinal ultrasound has high sensitivity and specificity in patients with suspected Crohn's disease and in the detection of inflammatory activity. This technique enables the early diagnosis of intra-abdominal complications such as stenosis, fistulas, and abscesses. It has also proven useful in monitoring the response to treatment and in detecting postsurgical recurrence. Technical improvements in ultrasound scanners, technological advances such as ultrasound contrast agents and elastography, and above all increased experience have increased the role of ultrasound in the evaluation of the gastrointestinal tract. The features that make ultrasound especially attractive include its wide availability, its noninvasiveness and lack of ionizing radiation, its low cost, and its good reproducibility, which is important because it is easy to repeat the study and the study is well tolerated during follow-up. This review summarizes the role of intestinal ultrasound in the detection and follow-up of inflammatory bowel disease.

[Usefulness of ultrasonography in children with right iliac fossa pain]

Acute pain in the right iliac fossa is common in children. It can arise from a wide variety of gastrointestinal and genitourinary processes that make up the differential diagnosis with acute appendicitis. In this article, we describe the most representative findings of these processes on ultrasonography. We emphasize the characteristics that enable these processes to be differentiated from acute appendicitis.

[Crohn's disease: the usefulness of MR enterography in the detection of recurrence after surgery]

OBJECTIVES

To determine the usefulness of MR enterography in the detection of recurrence in the ileocolonic anastomosis in patients with Crohn's disease that have undergone intestinal resection.

MATERIAL AND METHODS

We used MR enterography and ileocolonoscopy to study 30 patients with Crohn's disease who had undergone intestinal resection. To determine the degree of relapse, the findings at MR enterography were quantified using our own index of Crohn's disease activity and the findings at ileocolonoscopy were quantified using the Rutgeerts scale. Ileocolonoscopy was considered the gold standard.

RESULTS

Compared to the gold standard, MR enterography yielded 100% sensitivity, 60% specificity, 92.6% positive predictive value (PPV), 100% negative predictive value (NPV), and 93.3% diagnostic accuracy. The concordance between the degree of recurrence determined with MR enterography and with ileocolonoscopy was moderate (κ=0.41). However, when patients were classified into two groups (high or low grade) according to outcome and the possibility of repeat surgery, the concordance was excellent (κ=0.87). Using this classification, MR enterography had 85% sensitivity, 100% specificity, 100% PPV, and 76.9% NPV.

CONCLUSIONS

MR enterography is a useful imaging method for detecting recurrence of Crohn's disease after surgery and for differentiating between patients with higher or lower risk of poor outcome. MR enterography has good concordance with ileocolonoscopy and is an alternative to ileocolonoscopy in determinate occasions.

Crohn disease: correlation of findings at contrast-enhanced US with severity at endoscopy

PURPOSE

To evaluate the effectiveness of visualization of vascularization at contrast material-enhanced ultrasonography (US) for assessment of the activity of Crohn disease, with severity grade determined at endoscopy as the reference standard.

MATERIALS AND METHODS

Ethics committee approval and written informed consent were obtained. Sixty-one patients (age range, 21-67 years; median age, 36 years) who had Crohn disease underwent both colonoscopy and US, including color Doppler and contrast-enhanced US, prospectively. To assess the vascularization of the involved bowel loop in a region expected to be seen at colonoscopy, the contrast agent uptake was measured by using quantitative analysis of the enhancement in regions of interest. Measurement of contrast enhancement was assessed as the increase in wall brightness with respect to the baseline brightness. Results were compared with the severity grade determined at endoscopy by using the area under the receiver operating characteristic curve and logistic regression analysis.

RESULTS

Colonoscopy showed inflammatory lesions in 53 patients (mild disease, seven; moderate disease, 12; and severe disease, 34). Bowel wall thickness and grade at color Doppler US (P = .019 and .002, respectively) correlated with severity grade at endoscopy. Mural contrast enhancement in patients with active disease at endoscopy was markedly increased in comparison with enhancement in patients with inactive disease (P < .001). Multivariate logistic regression analysis revealed that an increase in wall brightness was a significant and independent variable predictive of severity grade at endoscopy. A threshold brightness value of percentage of increase of 46% had a sensitivity and specificity of 96% and 73%, respectively, in the prediction of moderate or severe grade for inflammation at endoscopy.

CONCLUSION

Quantitative measurements of bowel enhancement obtained by using contrast-enhanced US correlate with severity grade determined at endoscopy. Contrast-enhanced US could be a useful technique to monitor the activity of Crohn disease.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.2531082269/-/DC1.