Sebastian Bickelhaupt

MR imaging in Crohn's disease: correlation of MR motility measurement with histopathology in the terminal ileum

The objective of the study was to correlate MR‐detectable motility alterations of the terminal ileum with biopsy‐documented active and chronic changes in Crohns disease.

Crohn's disease: small bowel motility impairment correlates with inflammatory-related markers C-reactive protein and calprotectin

To evaluate the correlation between the levels of C‐reactive protein (CRP), calprotectin, and small bowel motility in patients with Crohns disease assessed with MRI.

Software-assisted small bowel motility analysis using free-breathing MRI: Feasibility study

To validate a software prototype allowing for small bowel motility analysis in free breathing by comparing it to manual measurements.

Differentiation between active and chronic Crohn's disease using MRI small-bowel motility examinations — Initial experience

AIM To evaluate the influence of locally active Crohns disease on systemic small-bowel motility in patients with chronic Crohns disease compared to healthy individuals. MATERIAL AND METHODS Fifteen healthy individuals (11 men, four women; mean age 37 years) and 20 patients with histopathologically proven active (n = 15; 10 women, 5 men; mean age 45 years) or chronic (n = 5; four women, one man; mean age 48 years) Crohns disease were included in this institutional review board-approved, retrospective study. Magnetic resonance imaging (MRI; 1.5 T) was performed after standardized preparation. Two-dimensional (2D) cine sequences for motility acquisition were performed in apnoea (27 s). Motility assessment was performed using dedicated software in three randomly chosen areas of the small-bowel outside known Crohns disease-affected hotspots. The main quantitative characteristics (frequency, amplitude, occlusion rate) were compared using Students t-test and one-way analysis of variance (ANOVA). RESULTS Three randomly chosen segments were analysed in each participant. Patients with active Crohns disease had significantly (p < 0.05) reduced contraction frequencies (active Crohns disease: 2.86/min; chronic: 4.14/min; healthy: 4.53/min) and luminal occlusion rates (active: 0.43; chronic: 0.70; healthy: 0.73) compared to healthy individuals and patients with chronic Crohns disease. Contraction amplitudes were significantly reduced during active Crohns disease (6.71 mm) compared to healthy participants (10.14 mm), but this only reached borderline significance in comparison to chronic Crohns disease (8.87 mm). Mean bowel lumen diameter was significantly (p = 0.04) higher in patients with active Crohns disease (16.91 mm) compared to healthy participants (14.79 mm) but not in comparison to patients with chronic Crohns disease (13.68). CONCLUSION The findings of the present study suggest that local inflammatory activity of small-bowel segments in patients with active Crohns disease alters small-bowel motility in distant, non-affected segments. The motility patterns revealed reduced contraction-wave frequencies, amplitudes, and decreased luminal occlusion rates. Thus evaluation of these characteristics potentially helps to differentiate between chronic and active Crohns disease.

Automatic detection of small bowel contraction frequencies in motility plots using lomb‐scargle periodogram and sinus‐fitting method—initial experience

Contraction frequencies are an important parameter for the analysis of bowel motility in MRI. The contraction curve can be rather noisy and the frequency‐evaluation might be difficult. The aim was to evaluate manual calculations of small bowel contraction frequency in comparison with automatic calculations using two mathematically established methods.

Software-assisted quantitative analysis of small bowel motility compared to manual measurements

AIM To validate a newly developed software prototype that automatically analyses small bowel motility by comparing it directly with manual measurement. MATERIAL AND METHODS Forty-five patients with clinical indication for small bowel magnetic resonance imaging (MRI) were retrospectively included in this institutional review board-approved study. MRI was performed using a 1.5 T system following a standard MR-enterography protocol. Small bowel motility parameters (contractions-per-minute, luminal diameter, amplitude) were measured three times each in identical segments using the manual and the semiautomatic software-assisted method. The methods were compared for agreement, repeatability, and time needed for each measurement. All parameters were compared between the methods. RESULTS A total of 91 small-bowel segments were analysed. No significant intra-individual difference (p > 0.05) was found for peristaltic frequencies between the methods (mean: 4.14/min manual; 4.22/min software-assisted). Amplitudes (5.14 mm; 5.57 mm) and mean lumen diameters (17.39 mm; 14.68) differed due to systematic differences in the definition of the bowel wall. Mean duration of single measurement was significantly (p < 0.01) shorter with the software (6.25 min; 1.30 min). The scattering of repeated measurements was significantly (p < 0.05) lower using the software. CONCLUSION The software-assisted method accomplished highly reliable, fast and accurate measurement of small bowel motility. Measurement precision and duration differed significantly between the two methods in favour of the software-assisted technique.

Software‐supported evaluation of gastric motility in MRI: A feasibility study

The aim of this study was to evaluate the feasibility of dedicated motility assessment software for quantitative evaluation of basic gastric motility and to validate it using manual measurements.

Small-bowel dislocation during long-term MRI observation - insights in intestinal physiology.

Magnetic resonance imaging (MRI) of the abdomen is a widely established imaging modality in the diagnostic workup of patients suffering from abdominal disorders. Small‐bowel motility analyses using MRI have recently been introduced to provide functional information about the intestine not provided by morphological analyses. This is of clinical importance as motility disorders correlate with inflammation. Yet motility analyses mainly rely on a series of acquisitions in coronal orientation. Temporal displacement of small‐bowel loops out of the coronal slice could falsify qualitative and quantitative motility analyses. Thus, our study quantified three‐dimensional (3D) dislocation of small‐bowel loops during abdominal MRI examinations with the patient lying in prone position to investigate its influence on motility analyses. Our study revealed segmental small‐bowel displacement during MRI examinations in prone position to predominantly occur in craniocaudal orientation and in a smaller extent in lateral and ventrodorsal orientation. However, the displacement amplitudes are rather small and might not significantly influence small‐bowel motility analyses in 2D coronal plane in general.

Correlation between morphological expansion and impairment of intra- and prelesionary motility in inflammatory small bowel lesions in patients with Crohn's disease – Preliminary data

INTRODUCTION The aim of this study is to investigate if alterations of intra- and prelesionary motility in inflamed small-bowel segments correlate with length, wall-thickness and prelesionary dilatation of inflammatory small bowel lesions in patients suffering from Crohns disease assessed with MRI. METHODS AND MATERIALS This retrospective IRB approved study included 25 patients (12 males, 18-77y) with inflammatory lesions examined using (MRE) magnetic resonance imaging enterography. Cine MRE was performed using a coronal 2D steady-state free precession sequence (TR 2.9, TE 1.25) on a 1.5T MRI scanner. Small bowel motility was examined using a dedicated MR-motility assessment software (Motasso, Vers. 1.0, Sohard AG, Bern, Switzerland). Motility patterns (contraction frequency, relative occlusion rate and mean diameter) were assessed in correlation to wall thickness, length and prelesionary dilatation of the lesions. Statistical analysis was performed by calculation of the Pearsons-Correlation coefficient. RESULTS The length of the inflammatory segments, the wall thickening and prelesionary dilatation did not correlate with the frequency of the contractions (r=0.17, p=0.477; r=0.316, p=0.123; r=0.161, p=0.441) or the impairment of luminal occlusion (r=0.274, p=0.184; r=0.199, p=.0339; r=0.015, p=0.945) and only the prelesionary dilatation (r=0.410, p=0.042) correlated to the mean luminal diameter of the segment. CONCLUSION The degree of motility impairment within inflammatory small bowel lesions does not significantly correlate with the extent of the lesion but with the motility measured in prelesionary, non-affected segments, suggesting an interdependent functional aspect of inflammation even in morphologically non-affected small bowel segments.

Quantitative in vivo analysis of small bowel motility using MRI examinations in mice – proof of concept study

Small bowel motility analyses using magnetic resonance imaging (MRI) could reduce current invasive techniques in animal studies and comply with the ‘three Rs’ rule for human animal experimentation. Thus we investigated the feasibility of in vivo small bowel motility analyses in mice using dynamic MRI acquisitions. All experimental procedures were approved by the institutional animal care committee. Six C57BL/6 mice underwent MRI without additional preparation after isoflurane anaesthetization in the prone position on a 4.7 T small animal imager equipped with a linear polarized hydrogen birdcage whole-body mouse coil. Motility was assessed using a true fast imaging in a steady precession sequence in the coronal orientation (acquisition time per slice 512 ms, in-plane resolution 234 × 234 µm, matrix size 128 × 128, slice thickness 1 mm) over 30 s corresponding to 60 acquisitions. Motility was manually assessed measuring the small bowel diameter change over time. The resulting motility curves were analysed for the following parameters: contraction frequency per minute (cpm), maximal contraction amplitude (maximum to minimum [mm]), luminal diameter (mm) and luminal occlusion rate. Small bowel motility quantification was found to be possible in all animals with a mean small bowel contraction frequency of 10.67 cpm (SD ± 3.84), a mean amplitude of the contractions of 1.33 mm (SD ± 0.43) and a mean luminal diameter of 1.37 mm (SD ± 0.42). The mean luminal occlusion rate was 1.044 (SD ± 0.45%/100). The mean duration needed for a single motility assessment was 185 s (SD ± 54.02). Thus our study demonstrated the feasibility of an easy and time-sparing functional assessment for in vivo small bowel motility analyses in mice. This could improve the development of small animal models of intestinal diseases and provide a method similar to clinical MR examinations that is in concordance with the ‘three Rs’ for humane animal experimentation.