Alex Menys

Quantified terminal ileal motility during MR enterography as a potential biomarker of Crohn’s disease activity: a preliminary study

AbstractObjectiveTo compare quantified terminal ileal (TI) motility during MR enterography (MRE) with histopathological severity of acute inflammation in Crohn’s disease.MethodsA total of 28 Crohn’s patients underwent MRE and endoscopic TI biopsy. Axial and coronal TrueFISP, HASTE and post-gadolinium VIBE images were supplemented by multiple coronal TrueFISP cine motility sequences through the small bowel volume. TI motility index (MI) was quantified using validated software; an acute inflammation score (eAIS; 0–6) was assigned to the biopsy. Two observers qualitatively scored mural thickness, T2 signal, contrast enhancement and perimural oedema (0–3) to produce an activity score (aMRIs) based on anatomical MRI. The association among the MI, eAIS and aMRIs was tested using Spearman’s rank correlation. Wilcoxon rank sum test compared motility in subjects with and without histopathological inflammation.ResultsMean MI and mean eAIS were 0.27 (range 0.06–0.55) and 1.5 (range 0–5), respectively. There was a significant difference in MI between non-inflamed (mean 0.37, range 0.13–0.55) and inflamed (mean 0.19, range 0.06–0.44) TI, P = 0.002, and a significant negative correlation between MI and both eAIS (Rho = −0.52, P = 0.005) and aMRIs (R = −0.7, P < 0.001).ConclusionQuantified TI motility negatively correlates with histopathological measures of disease activity and existing anatomical MRI activity biomarkers.Key Points• Magnetic resonance imaging is increasingly used to assess Crohn’s disease. • MRI measurements can provide a quantitative assessment of small bowel motility. • MR enterography can grade Crohn’s disease. • Small bowel motility can be used as a marker of inflammatory activity.

Respiratory motion correction in dynamic MRI using robust data decomposition registration - application to DCE-MRI.

Motion correction in Dynamic Contrast Enhanced (DCE-) MRI is challenging because rapid intensity changes can compromise common (intensity based) registration algorithms. In this study we introduce a novel registration technique based on robust principal component analysis (RPCA) to decompose a given time-series into a low rank and a sparse component. This allows robust separation of motion components that can be registered, from intensity variations that are left unchanged. This Robust Data Decomposition Registration (RDDR) is demonstrated on both simulated and a wide range of clinical data. Robustness to different types of motion and breathing choices during acquisition is demonstrated for a variety of imaged organs including liver, small bowel and prostate. The analysis of clinically relevant regions of interest showed both a decrease of error (15-62% reduction following registration) in tissue time-intensity curves and improved areas under the curve (AUC60) at early enhancement.

Global Small Bowel Motility: Assessment with Dynamic MR Imaging

PURPOSE To assess the repeatability in human volunteers of software-quantified small bowel motility captured with magnetic resonance (MR) imaging and to test the ability to detect changes in motility induced by pharmacologic agents. MATERIALS AND METHODS The study was approved by the Royal Free Research Ethics Committee, and all subjects gave full written informed consent. Twenty-one healthy volunteers (14 men, seven women; mean age, 28 years) underwent cine MR imaging with a three-dimensional balanced turbo field-echo sequence to capture small bowel motility. Volume blocks (15 cm thick) were acquired every second during a 20-second breath hold. A randomized, blinded, placebo-controlled crossover study of either 0.5 mg neostigmine or saline (n = 11) or 20 mg intravenous butylscopolamine or saline (n = 10) was performed with motility MR imaging at baseline and repeated at a mean of 4 weeks (range, 2-7 weeks). Two readers independently drew regions of interest around the small bowel, and motility was quantified by using a registration algorithm that provided a global motility metric in arbitrary units. Repeatability of the motility measurements at baseline was assessed by using Bland-Altman and within-subject coefficient of variation measures. Changes in mean motility measurements after drug administration were compared with those after placebo administration by using paired t testing. RESULTS The repeatability between baseline measurements of motility was high; the Bland-Altman mean difference was -0.0025 (range, 0.28-0.4), the 95% limit of agreement was ±0.044 arbitrary units (au), and the within-subject coefficient of variation was 4.9%. Measured motility with neostigmine (mean, 0.39 au) was significantly higher than that with placebo (mean, 0.34 au; P < .001), whereas that with butylscopolamine (mean, 0.13 au) was significantly lower than that with placebo (mean, 0.30 au; P < .001). CONCLUSION Quantification of small bowel motility with use of MR imaging in healthy volunteers is repeatable and sensitive to changes induced by means of pharmacologic manipulation. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13130151/-/DC1.

Small bowel strictures in Crohn’s disease: a quantitative investigation of intestinal motility using MR enterography

Intestinal stricturing and aberrant small bowel motility are common complications in patients with Crohns disease (CD) leading to significant morbidity. A retrospective study was performed quantifying small bowel motility within and upstream of strictures in CD patients using magnetic resonance enterography (MRE).

Magnetic resonance imaging-quantified small bowel motility is a sensitive marker of response to medical therapy in Crohn's disease

Magnetic resonance enterography (MRE) can measure small bowel motility, reduction in which reflects inflammatory burden in Crohns Disease (CD). However, it is unknown if motility improves with successful treatment.

Colonic response to laxative ingestion as assessed by MRI differs in constipated irritable bowel syndrome compared to functional constipation

Functional constipation (FC) and irritable bowel syndrome with constipation (IBS‐C) share many symptoms but underlying mechanisms may be different. We have developed a magnetic resonance imaging (MRI) technique to measure intestinal volumes, transit, and motility in response to a laxative, Moviprep®. We aim to use these biomarkers to study the pathophysiology in IBS‐C and FC.

Dual registration of abdominal motion for motility assessment in free-breathing data sets acquired using dynamic MRI

At present, registration-based quantification of bowel motility from dynamic MRI is limited to breath-hold studies. Here we validate a dual-registration technique robust to respiratory motion for the assessment of small bowel and colonic motility. Small bowel datasets were acquired in breath-hold and free-breathing in 20 healthy individuals. A pre-processing step using an iterative registration of the low rank component of the data was applied to remove respiratory motion from the free breathing data. Motility was then quantified with an existing optic-flow (OF) based registration technique to form a dual-stage approach, termed Dual Registration of Abdominal Motion (DRAM). The benefit of respiratory motion correction was assessed by (1) assessing the fidelity of automatically propagated segmental regions of interest (ROIs) in the small bowel and colon and (2) comparing parametric motility maps to a breath-hold ground truth. DRAM demonstrated an improved ability to propagate ROIs through free-breathing small bowel and colonic motility data, with median error decreased by 90% and 55%, respectively. Comparison between global parametric maps showed high concordance between breath-hold data and free-breathing DRAM. Quantification of segmental and global motility in dynamic MR data is more accurate and robust to respiration when using the DRAM approach.

The challenge of segmental small bowel motility quantitation using MR enterography

Objective: Analysis of “cine” MRI using segmental regions of interest (ROIs) has become increasingly popular for investigating bowel motility; however, variation in motility in healthy subjects both within and between scans remains poorly described. Methods: 20 healthy individuals (mean age, 28 years; 14, males) underwent MR enterography to acquire dynamic motility scans in both breath hold (BH) and free breathing (FB) on 2 occasions. Motility data were quantitatively assessed by placing four ROIs per subject in different small bowel segments and applying two measures: (1) contractions per minute (CPM) and (2) Jacobian standard deviation (SD) motility score. Within-scan (between segment) variation was assessed using intraclass correlation (ICC), and repeatability was assessed using Bland–Altman limits of agreement (BA LoA). Results: Within-scan segmental variation: BH CPM and Jacobian SD metrics between the four segments demonstrated ICC R = 0.06, p = 0.100 and R = 0.20, p = 0.027 and in FB, the CPM and Jacobian SD metrics demonstrated ICC R = −0.26, p = 0.050 and R = 0.19, p = 0.030. Repeatability: BH CPM for matched segments ranged between 0 and 14 contractions with BA LoA of ±8.36 and Jacobian SD ranged between 0.09 and 0.51 with LoA of ±0.33. In FB data, CPM ranged between 0 and 10 contractions with BA LoA of ±7.25 and Jacobian SD ranged between 0.16 and 0.63 with LoA = ±0.28. Conclusion: The MRI-quantified small bowel motility in normal subjects demonstrates wide intersegmental variation and relatively poor repeatability over time. Advances in knowledge: This article presents baseline values for healthy individuals of within- and between-scan motility that are essential for understanding how this process changes in disease.

Comparative quantitative assessment of global small bowel motility using magnetic resonance imaging in chronic intestinal pseudo-obstruction and healthy controls.

Chronic intestinal pseudo‐obstruction (CIPO) is characterized by dilatation of the bowel lumen and abnormal motility. In this study, we aimed to quantify small bowel dysmotility in CIPO using a validated pan‐intestinal motility assessment technique based on motion capture magnetic resonance imaging (MRI) compared to normal controls. In addition, we explored if motility responses of CIPO patients to neostigmine challenge differed from healthy volunteers.

Colon wall motility: comparison of novel quantitative semi‐automatic measurements using cine MRI

Recently, cine magnetic resonance imaging (MRI) has shown promise for visualizing movement of the colonic wall, although assessment of data has been subjective and observer dependent. This study aimed to develop an objective and semi‐automatic imaging metric of ascending colonic wall movement, using image registration techniques.