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P253. Conventional and contrast-enhanced ultrasound (CEUS) in the evaluation of Crohn's disease activity

L. Ballesteros, M. Calvo, M.P. Delgado, A.M. Martín, P. Martínez, B. Casis, G. Castellano, Hospital Universitario 12 de Octubre, Gastroenterology, Madrid, Spain

Background

To investigate the utility of ultrasound examination (US), including conventional and contrast-enhanced US (CEUS), in the assessment of Crohn's disease activity.

Methods

This was a retrospective study of patients with confirmed Crohn's disease (CD) undergoing abdominal ultrasound examination (US) specifically for the intestine, including CEUS, recruited between January 2012 and October 2013. The Harvey–Bradshaw Index (HBI) was calculated to define CD activity: the disease was classified as active when HIB score was 3 or higher. Laboratory assessment including C-reactive protein (CRP), leucocytes, and fibrinogen were performed in every patient. The US examination was used to assess the location of the affected intestinal segment and its wall thickness. Thereafter, dynamic CEUS examination was carried out using the second generation US contrast agent SonoVue®. The parameter evaluated in this study was the percentage of increase in wall brightness (PIB) of the thickest bowel segment. 35 patients were evaluated by MRI, defining active disease according to radiologist criteria. Sonographic findings were compared with laboratory, clinical and imaging assessment (Wilcoxon test, Spearman, ROC analysis).

Results

135 patients were enrolled in the study (69 males, 66 females), with a mean age of 44.6 years. HBI was indicative of active disease in 62 patients (54.1%) and of inactive disease in 73 (45.9%) Median wall thickness values for the two subgroups were similar, however the percentage of increase in wall brightness was markedly higher in patients with active disease, as well as CRP and median leukocyte count (p = 0.002, p < 0.001 and p = 0.01 respectively) (Table 1).

Both of the US parameters analyzed (wall thickness and PIB) showed positive correlation with acute phase reactants (Table 2).

The percentage of increase in wall brightness at ultrasound showed a good correlation with MRI results (p = 0.04). ROC analysis of the accuracy of the US parameters (compared with HBI) revealed that cutoff values of 5 mm for the wall thickness and 70% for the PIB displayed high sensitivity (76% and 79%) but poor specificity (36% and 40%).

Table 1. Clinical features, US and MRI parameters for the study population
ParameterAll patients (n = 135)Inactive disease (IHB < 5)
n = 73
Active disease (IHB ≥ 5)
n = 62
P value
CRP (mg/dL)1.2(±2.3)0.6(±0.9)1.9(±3.1)0.002
Fibrinogen (mg/mL)438.3`107.4)424.6(±87.4)453.6(±125)NS
Leucocytes (cells/mm3)8309(±3536)7036(±2579)9810(±3923)<0.001
MRI (n = 35)
 Signs of activity27 (77.1%)6 (66.7%)21 (80.8%)NS
 Without signs of activity8 (22.9%)3 (33.3%)5 (19.2%)NS
Bowel wall thickness in US (mm)5.9(±2)5.6(±1.7)6.3(±2.2)NS
CEUS: PIB (%)92.3(±47.8)84(±47.6)101.9(±46.6)0.011
Number in parentheses is the standard deviation; NS: no significant difference (p > 0.05).
Table 2. Correlation between US parameters and clinical variables
ParameterBowel wall thicknessPIB (CEUS)
SpearmanP valueSpearmanP value
Harvey–Bradshaw Index0.112NS0.2270.008
CRP0.321<0.0010.2070.017
Fibrinogen0.317<0.0010.2690.002
Leucocytes0.1990.0210.1980.021
NS: no significant difference (p > 0.05).

Conclusion

CEUS showed correlation with clinical, laboratory an MRI assessment. Conventional and contrast enhanced US could be a useful method to assess the inflammatory activity in CD and an alternative to MRI.