TY - JOUR
T1 - Rectal Gas Volume Measured by Computerized Tomography Identifies Evacuation Disorders in Patients With Constipation
AU - Park, Seon Young
AU - Khemani, Disha
AU - Nelson, Alfred D.
AU - Eckert, Deborah
AU - Camilleri, Michael
N1 - Funding Information:
Funding Supported by National Institutes of Health grant R01-DK92179 (M.C.).
Publisher Copyright:
© 2017 AGA Institute
PY - 2017/4/1
Y1 - 2017/4/1
N2 - Background & Aims Approximately one third of patients who present to gastroenterology care with constipation have rectal evacuation disorders. We aimed to compare rectal gas volume, measured by computerized tomography (CT), in constipated patients with and without rectal evacuation disorders. Methods In a retrospective study, we collected data from 1553 patients with constipation, evaluated over 20 years. We analyzed data from 141 patients evaluated by anorectal manometry, balloon expulsion tests, and colon transit tests, collecting records of abdominal and pelvic CT examinations. Patients were classified into 3 subgroups: those with rectal evacuation disorders, slow-transit constipation, or normal-transit constipation. Two observers used standard CT software to identify variable regions of interest on each cross-sectional CT image that contained rectum and measured areas of gas in each slice; they then summated entire volumes of rectal gas. For the 3 groups, we compared rectal gas volume, maximal rectal gas transaxial area (measured by CT), and area of rectal gas (vertical) on the 2-dimensional abdominal film (scout) using the Kruskal–Wallis test. Results The intraclass correlation coefficient between 2 observers’ measurements of rectal gas volume was 0.99 (P < .001). There were overall group differences in rectal gas volume and the maximal rectal gas transaxial area (both P < .001). The median rectal gas volume was higher in patients with rectal evacuation disorders (13.84 cm3) than in patients with slow-transit (2.51 cm3) or normal-transit constipation (1.33 cm3, both P < .05). Similarly, the area of rectal gas, which correlated with the maximal rectal gas transaxial area (Spearman correlation coefficient, 0.7; P < .001), showed overall 3-group differences (P = .033), with greater areas of rectal gas on the abdominal scout film in patients with rectal evacuation disorders than in those with normal-transit constipation. Conclusions In an analysis of patients with constipation, we found rectal gas volume, determined by abdominal CT imaging, to be greater in patients with than without rectal evacuation disorders.
AB - Background & Aims Approximately one third of patients who present to gastroenterology care with constipation have rectal evacuation disorders. We aimed to compare rectal gas volume, measured by computerized tomography (CT), in constipated patients with and without rectal evacuation disorders. Methods In a retrospective study, we collected data from 1553 patients with constipation, evaluated over 20 years. We analyzed data from 141 patients evaluated by anorectal manometry, balloon expulsion tests, and colon transit tests, collecting records of abdominal and pelvic CT examinations. Patients were classified into 3 subgroups: those with rectal evacuation disorders, slow-transit constipation, or normal-transit constipation. Two observers used standard CT software to identify variable regions of interest on each cross-sectional CT image that contained rectum and measured areas of gas in each slice; they then summated entire volumes of rectal gas. For the 3 groups, we compared rectal gas volume, maximal rectal gas transaxial area (measured by CT), and area of rectal gas (vertical) on the 2-dimensional abdominal film (scout) using the Kruskal–Wallis test. Results The intraclass correlation coefficient between 2 observers’ measurements of rectal gas volume was 0.99 (P < .001). There were overall group differences in rectal gas volume and the maximal rectal gas transaxial area (both P < .001). The median rectal gas volume was higher in patients with rectal evacuation disorders (13.84 cm3) than in patients with slow-transit (2.51 cm3) or normal-transit constipation (1.33 cm3, both P < .05). Similarly, the area of rectal gas, which correlated with the maximal rectal gas transaxial area (Spearman correlation coefficient, 0.7; P < .001), showed overall 3-group differences (P = .033), with greater areas of rectal gas on the abdominal scout film in patients with rectal evacuation disorders than in those with normal-transit constipation. Conclusions In an analysis of patients with constipation, we found rectal gas volume, determined by abdominal CT imaging, to be greater in patients with than without rectal evacuation disorders.
KW - Abdominal Radiograph
KW - Balloon Expulsion
KW - Colonic Transit
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U2 - 10.1016/j.cgh.2016.11.013
DO - 10.1016/j.cgh.2016.11.013
M3 - Article
C2 - 27856363
AN - SCOPUS:85013072463
VL - 15
SP - 543-552.e4
JO - Clinical Gastroenterology and Hepatology
JF - Clinical Gastroenterology and Hepatology
SN - 1542-3565
IS - 4
ER -