Quantification and variability in colonic volume with a novel magnetic resonance imaging method

Abstract

Key Messages• The aim of this study was to describe the inter-individual and intra-individual variability in segmental volume of the undisturbed colon between two observations and the effect of defecation on the segmental volumes.• Variability of segmental colorectal volumes was assessed with a novel semi-automatic MRI-based technique in healthy males in a controlled fasting state.• Despite being a highly dynamic organ, the colon displays low intra-individual variability and the technique is sensitive to the changes in segmental colorectal volume that occur from defecation. AbstractBackground Segmental distribution of colorectal volume is relevant in a number of diseases, but clinical and experimental use demands robust reliability and validity. Using a novel semi-automatic magnetic resonance imaging-based technique, the aims of this study were to describe: (i) inter-individual and intra-individual variability of segmental colorectal volumes between two observations in healthy subjects and (ii) the change in segmental colorectal volume distribution before and after defecation. Methods The inter-individual and intra-individual variability of four colorectal volumes (cecum/ ascending colon, transverse, descending, and rectosigmoid colon) between two observations (separated by 52 AE 10) days was assessed in 25 healthy males and the effect of defecation on segmental colorectal volumes was studied in another seven healthy males. Key Results No significant differences between the two observations were detected for any segments (All p > 0.05). Inter-individual variability varied across segments from low correlation in cecum/ascending colon (intra-class correlation coefficient [ICC] = 0.44) to moderate correlation in the descending colon (ICC = 0.61) and high correlation in the transverse (ICC = 0.78), rectosigmoid (ICC = 0.82), and total volume (ICC = 0.85). Overall intra-individual variability was low (coefficient of variance = 9%). After defecation the volume of the rectosigmoid decreased by 44% (p = 0.003). The change in rectosigmoid volume was associated with the true fecal volume (p = 0.02). Conclusions & Inferences Imaging of segmental colorectal volume, morphology, and fecal accumulation is advantageous to conventional methods in its low variability, high spatial resolution, and its absence of contrast-enhancing agents and irradiation. Hence, the method is suitable for future clinical and interventional studies and for characterization of defecation physiology.

MRI analysis of fecal volume and dryness: Validation study using an experimental oxycodone‐induced constipation model

“…Bendezú et al investigated how colonic, fecal, and gas volumes differed with a low‐ and high‐residue diet, and found that diet altered all three parameters. Moreover, we did not restrict subjects to refrain from defecation in the mornings of the scans; however, it has previously been shown that defecation significantly decreases the volume of the distal colon . The variation found between individual fecal volumes on the two baseline scans varied according to what could be explained by diets and normal physiology, including contractions and relaxations that affects colonic length .…”

“…All data analysis was performed using a semiautomatic volumetric segmentation platform (MatLab v. R2016a, MathWorks, Natick, MA) that has been used in several other studies . In short, the observer outlines a coarse region of interest encapsulating the colon on each of the 35–40 abdominal coronal images where the colon is shown.…”

Colon Hypersensitivity to Distension, Rather Than Excessive Gas Production, Produces Carbohydrate-Related Symptoms in Individuals With Irritable Bowel Syndrome

“…The methods for measurement of SBWC and colonic volume have been described in detail previously 17,20 . The sigmoid colon, is normally collapsed and not included in the measurement of the descending colon, however in this study it was noted to often be markedly distended and so was measured by our usual technique, as has recently been shown to be feasible by other groups 32 . Ultimately 36/ 58 individuals had a measurable sigmoid colon for at least one time point, and in 20/58 this was more than 50mL, values which were included in the total colon volume.…”

Characterizing chronic and acute health risks of residues of veterinary drugs in food: latest methodological developments by the joint FAO/WHO expert committee on food additives

“…As this is an anatomical parameter, the same value should be applicable when deriving a microbiological ARfD. However, in developing its guidance for establishing a microbiological ARfD, JECFA (FAO/WHO 2016a) noted that a number of recent studies (Khashab et al 2009;Pritchard et al 2014;Nilsson et al 2015) using state-of-the-art imaging techniques, had indicated that the true volume of the hydrated colon of healthy individuals is greater than the estimate used in VICH GL36(R) (VICH 2012) and in EHC 240 (FAO/WHO 2009a). JECFA concluded that a more realistic, conservative estimate of this parameter, applicable to the derivation of both a microbiological ADI and a microbiological ARfD, would be 500 ml, but that this should be subject to further review before a final decision is taken on the value for future use.…”