Measuring disease activity in Crohn’s disease

Bowel contrast-enhanced ultrasound perfusion imaging in the evaluation of Crohn's disease patients undergoing anti-TNFα therapy

AIM

To evaluate whether changes in bowel perfusion parameters measured by dynamic-CEUS (D-CEUS) can be used for monitoring response to therapy in active Crohn disease (CD).

METHODS

Fifty-four CD patients were evaluated with d-CEUS before (T0) and after 2 (T1), 6 (T2) and 12 weeks (T3) of anti-TNFα therapy. Variations from baseline were calculated for: peak intensity, PI; area under the curve, AUC; slope of wash in, P_w; time to peak, TP; mean transit time, MTT (median percentage values) and were correlated with combined endoscopic/clinical response after 12 weeks and clinical relapse within 6 months.

RESULTS

70% of patients achieved combined endoscopic/clinical response (responders). The reduction in PI, AUC, P_w and MTT between T1 and T0 was higher in responders. Relapsers (21%) showed significantly lower reduction in delta PI and P_w at T1 and T2. At T3 they showed a new increase in PI and lower reduction in delta P_w. In relapsers, AUC showed a significantly lower decrease at T2 and T3, TP showed a significant reduction at T3 and MTT showed a progressive increase at the different time-points, reaching the statistical significance at T3.

CONCLUSIONS

d-CEUS might become a reliable predictor of combined endoscopic/clinical response and clinical relapse in CD.

Early Predictors of the Long-term Response to Therapy in Patients With Crohn Disease Derived From a Time-Intensity Curve Analysis After Microbubble Contrast Agent Injection

OBJECTIVES

The aim of this study was to identify early predictors of the long-term response to therapy in patients with Crohn disease (CD) from time-intensity curves obtained after microbubble injection.

METHODS

One hundred fifteen consecutive patients with a proven diagnosis of CD involving the terminal ileal loop who were scheduled to begin pharmacologic therapy with biologics (infliximab or adalimumab) were scanned after sulfur hexafluoride-filled microbubble injection before the beginning and at the end of the sixth week of treatment. The absolute value and percentage change of each semiquantitative kinetic parameter (peak enhancement, time to peak enhancement, rise time, mean transit time, wash-in and wash-out rates, area under the curve [AUC] for the whole time-intensity curve, AUC during wash-in, AUC during wash-out, and wash-in perfusion index) as measured on the terminal ileal tract and adjacent reactive mesenteric fat were calculated from time-intensity curves. Patients were followed for at least 24 months with redetermination of the Crohn Disease Activity Index and with at least 1 endoscopy within 18 weeks after the beginning of pharmacologic treatment. The absolute values and percentage changes of kinetic parameters were assessed as potential predictors of the therapeutic outcome by a logistic regression analysis.

RESULTS

The study group included 66 male and 49 female patients (mean age ± SD, 45.76 ± 11 years). The pretreatment values and percentage changes of the peak enhancement, AUC, AUC during wash-in, and AUC during wash-out were found to be predictors (P < .05) of the long-term therapeutic outcome.

CONCLUSIONS

The analysis of time-intensity curves obtained after microbubble contrast agent injection provides early predictors of the long-term therapeutic outcome in patients with CD.

CT enterography: Diagnostic value of 4th generation iterative reconstruction algorithm in low dose studies in comparison with standard dose protocol for follow-up of patients with Crohn's disease

PURPOSE

To compare radiation dose, image quality and diagnostic performance of low dose CT enterography (CTE) protocol combined with iterative reconstruction algorithm (iDose(4)) with standard dose CTE in follow-up of patients with known Crohn's disease (CD).

MATERIALS AND METHOD

Thirty-six patients (12 females), with CD underwent a low-dose CTE scan during single venous phase on 256 MDCT scanner, with the following parameters: 120 kV, automated mAs dose-modulation, slice thickness 2mm and iDose(4) iterative reconstruction algorithm. A control group of thirty-seven patients underwent standard dose CTE examination on the same CT scanner. Two radiologists, blinded to clinical and pathological findings, independently evaluated in each scan, HU values in bowel wall and any presence of CD activity features and disease complications. Image noise and diagnostic quality were evaluated using a 4-point scale. Dose-length product (DLP) and CT-dose-index (CTDI) were recorded and data from both examinations were compared and statistically analyzed.

RESULTS

Low-dose CTE protocol showed high diagnostic quality in assessment of Crohn's disease obtaining significantly (p ≤ 0.001) lower values of DLP and CTDI (604.98 mGy*cm and 12.29 mGy) as compared to standard dose examinations (974.85 mGy*cm and 19.71 mGy), with an overall dose reduction of 37.6%. Noise resulted slightly higher in iDose(4) images (SD=15.97) than in standard dose ones (SD=13.61) but this difference was not statistically significant (p=0.064).

CONCLUSION

Low-dose CTE combined with iDose(4) reconstruction algorithm offers high quality images with significant reduction of radiation dose, and therefore can be considered a useful tool in the management of CD patients, considering their young age and the frequent imaging follow-up required.

Biochemical markers and MR imaging findings as predictors of crohn disease activity in patients scanned by contrast-enhanced MR enterography

RATIONALE AND OBJECTIVES

To define the best independent predictors for active inflammation in patients with Crohn disease (CD) examined by contrast-enhanced magnetic resonance (MR) enterography.

MATERIALS AND METHODS

Ninety-one patients (47 men and 44 women; aged 39.58 ± 17.1 years) with a diagnosis of CD; CD activity index (CDAI) ≥ 150 (n = 19 patients) or <150 (n = 72) underwent MR enterography including T2-weighted half-Fourier acquisition single-shot turbo spin-echo, T2-weighted spectral fat presaturation with inversion recovery, T1-weighted balanced steady-state free precession, and T1-weighted breath-hold resolution isotropic high volume three-dimensional MR imaging sequences before and after administration of gadobenate dimeglumine during arterial (30 seconds), portal venous (70 seconds), and delayed phase (3 and 5 minutes from contrast injection). Two readers analyzed the MR images in consensus. Reference standard was the Crohn's Disease Endoscopic Index of Severity (CDEIS) with deep mucosal biopsy or the histologic analysis of the surgical specimen in those patients (n = 30) who underwent elective small-bowel resection. Univariate and multivariate logistic regression analyses were performed to assess CDAI, biochemical markers (C-reactive protein and fecal calprotectin levels) and MR imaging findings as potential predictors of inflammatory CD activity.

RESULTS

Patients revealed prevalently active (n = 47 patients) or quiescent CD with mural fibrosis (n = 44 patients). The bowel wall T2 hyperintensity (odds ratio [OR], 9.20; 95% confidence interval [CI], 2.71-31.19) and total length of disease (OR, 1.29; 95% CI, 1.11-1.49) were found as the best independent predictors of active CD. CDAI, C-reactive protein, and fecal calprotectin were not found independent predictors of active CD.

CONCLUSIONS

The bowel wall T2 hyperintensity and the length of the involved bowel tract were predictors of active inflammation in patients with CD examined by contrast-enhanced MR enterography.

Assessment of disease behavior in patients with Crohn's disease by MR enterography

BACKGROUND

Magnetic resonance imaging (MRI) of the bowel is an increasingly used modality to evaluate patients with Crohn's disease. The Montreal classification of the disease behavior is considered as an excellent prognostic and therapeutic parameter for these patients. In our study, we correlated the behavior assessment performed by a radiologist based on MRI with the surgeons' clinical assessment based on the assessment during abdominal surgery.

METHODS

We evaluated 76 patients with Crohn's disease, who underwent bowel resection and had an MRI within 4 weeks before surgery. Radiological behavior assessment was performed by 2 radiologists based on MRI. Behavior was classified into B1 (nonstricturing and nonpenetrating), B2, and B3 (penetrating) disease. Surgical assessment was done by the same surgeon, who performed all bowel resections, based on intraoperative findings and histologic results.

RESULTS

The surgical assessment identified 4 patients (5%) as B1, 16 patients (21%) as B2, and 56 patients (74%) as B3. In 97% (n = 74) of all patients, the intraoperative and radiological assessment were identical with interobserver agreement of 0.937. In one case, B2 was radiological considered as B1, and in another case, B3 was diagnosed as B2. The diagnosis of a stricture had the highest sensitivity of 96%, whereas the detection of inflammatory mass showed the lowest sensitivity of 81%. Abscesses had the lowest positive predictive value of 68% with a specificity of 88%. Best correlation was found for fistulae (0.895).

CONCLUSIONS

MRI represents an excellent imaging modality to correctly assess the Montreal classification-based disease behavior in patients scheduled for bowel resection with Crohn's disease.