Performance of two neutral oral contrast agents in CT enterography

Comparison of the Efficacy of Diluted Polyethylene Glycol and Low-Density (0.1% w/v) Barium Sulfate Suspension for CT Enterography

PURPOSE

To compare small bowel distension and side effects between a diluted polyethylene glycol (PEG) solution and a low-density (0.1% w/v) barium sulfate suspension (LDBSS) for CT enterography (CTE) preparation.

MATERIALS AND METHODS

Total 173 consecutive patients who underwent CTE were enrolled in this study. The LDBSS (1 L) was used in 50 patients, and the diluted iso-osmotic PEG solution (1 L) was used in 123 patients. Two blinded radiologists independently scored jejunal and ileal distensions on a 5-point scale. To compare side effects between the two groups, the patients reported whether they had immediate complications after the administration of the oral contrast media.

RESULTS

For ileal and jejunal distension, the diluted PEG solution showed no difference from the LDBSS for either reader (ileum: reader 1, median, 4; 4, interquartile range, 3-4; 3-4, p = 0.997; reader 2, median, 4; 4, interquartile range, 3.3-4.0; 3-4, p = 0.064; jejunum: reader 1, median, 2; 2, interquartile range, 2-3; 2-3, p = 0.560; reader 2, median, 3; 2, interquartile range, 2-3; 2-3, p = 0.192). None of the patients complained of immediate complications following administration of either of the oral contrast media.

CONCLUSION

The diluted PEG solution showed comparable bowel distension compared to LDBSS and no immediate side effects; thus, it can be a useful alternative.

CT Enterography Using Four Different Endoluminal Contrast Agents: A Comparative Study

Objectives To determine the most preferable endoluminal contrast agent among mannitol, polyethylene glycol (PEG), iohexol, and water by comparing various qualitative (distension, fold visibility, and homogeneity) and quantitative parameters (distension) along with artifacts and patient feedback for computed tomography enterography (CTE).

Methods This was a prospective study including 120 patients of age more than or equal to 18 years who were randomized equally into four groups. Group 1 was given 1500 mL of 3% mannitol solution, group 2 was given 1500 mL of PEG, group 3 was given 20 mL of iohexol dissolved in 1500 mL of water, and group 4 was given 1500 mL of plain water. CTE was done and images were evaluated in axial and coronal planes. Various quantitative and qualitative parameters were taken at the level of second part of duodenum, jejunum, ileum and ileocecal junction (ICJ). Artifacts and patient feedback were also taken into consideration.

Results The quantitative distension and grading, qualitative distension, fold visibility, and homogeneity of the second part of duodenum, jejunum at the level of superior mesenteric artery, inferior mesenteric artery and renal artery on both sides of abdomen, ileum at the level of aortic bifurcation, common iliac bifurcation, and deep pelvis on both sides of abdomen and ICJ were significantly more in PEG group as compared with mannitol group, followed by iohexol and water group. The results were calculated by ANOVA test using p-value. In terms of patient feedback and artifacts, water was the best agent.

Conclusions PEG is the most suitable contrast agent to carry out CTE. Distension, fold visibility, and homogeneity are the essential features for a better diagnostic outcome of CTE, which was better with PEG.

An MSCT-based radiomics nomogram combined with clinical factors can identify Crohn's disease and ulcerative colitis

Background

We established and evaluated a radiomics nomogram based on multislice computed tomography (MSCT) arterial phase contrast-enhanced images to distinguish between Crohn's disease (CD) and ulcerative colitis (UC) objectively, quantitatively, and reproducibly.

Methods

MSCT arterial phase-enhancement images of 165 lesions (99 CD, 66 UC) in 87 patients with inflammatory bowel disease (IBD) confirmed by endoscopy or surgical pathology were retrospectively analyzed. A total of 132 lesions (80%) were selected as the training cohort and 33 lesions (20%) as the test cohort. A total of 1648 radiomic features were extracted from each region of interest (ROI), and the Pearson correlation coefficient and tree-based method were used for feature selection. Five machine learning classifiers, including logistic regression (LR), support vector machine (SVM), random forest (RF), stochastic gradient descent (SGD), and linear discriminative analysis (LDA), were trained. The best classifier was evaluated and obtained, and the results were transformed into the Rscore. Three clinical factors were screened out from 8 factors by univariate analysis. The logistic regression method was used to synthesize the significant clinical factors and the Rscore to generate the nomogram, which was compared with the clinical model and LR model.

Results

Among all machine learning classifiers, LR performed the best (AUC =0.8077, accuracy =0.697, sensitivity =0.8, specificity =0.5385), SGD model had the second best performance (AUC =0.8, accuracy =0.6667, sensitivity =0.75, specificity =0.5385), and the DeLong test results showed that there was no significant difference between LR and SGD (P=0.465>0.05), while the other models performed poorly. Texture features had the greatest impact on classification results among all imaging features. The significant features of the LR model were used to calculate the Rscore. The 3 significant clinical factors were perienteric edema or inflammation, CT value of arterial phase-enhancement (AP-CT value), and lesion location. Finally, a nomogram was constructed based on the 3 significant clinical factors and the Rscore, whose AUC (0.8846) was much higher than that of the clinical model (0.6154) and the LR model (0.8077).

Conclusions

The nomogram is expected to provide a new auxiliary tool for radiologists to quickly identify CD and UC.

Comparison of two small bowel distending agents for enterography in pediatric small bowel imaging

OBJECTIVE

To evaluate the ability of pediatric patients with known or suspected inflammatory bowel disease to ingest a new oral distending agent at CT or MR enterography (CTE/MRE), and to determine the impact on small bowel (SB) distension and diagnostic confidence.

MATERIALS AND METHODS

The study design is that of retrospective review of pediatric patients who underwent CTE or MRE from January 2014 to June 2016. Patients ingested low-concentration barium suspension or flavored beverage containing sorbitol and mannitol. The need for nasogastric tube (NGT) administration, amount ingested, emesis, distal extent of contrast, SB distension, terminal ileum (TI) transverse dimension, and diagnostic confidence in TI disease were assessed. Three radiologists each blindly reviewed a subset of the studies.

RESULTS

Of the total 591 scans in 504 patients, 316 scans used low-concentration barium suspension and 275 scans flavored beverage. Nearly all consumed the entire amount (97% vs. 96%). Low-concentration barium suspension exams required NGT more often (7% [23/316] vs. 1% [3/275]; p < 0.0003), and tended to have more emesis (3% [9/316] vs. 1% [3/275]; p = 0.13). Diagnostic confidence score was nearly identical (p = 0.94). Qualitative and quantitative analyses showed no difference in SB distension, except for distension of mid-ileum (flavored beverage > low-concentration barium suspension; p = 0.02). Flavored beverage exams demonstrated a slight increase in distal extent of luminal distension (p = 0.02).

CONCLUSIONS

A new flavored beverage distends small bowel as well as low-concentration barium suspension, with decreased requirement for NGT insertion and improved distal extent of luminal distension, and without any decrease in diagnostic confidence in the presence or the absence of TI disease.

Evaluation of bowel distension and bowel wall visualization according to patient positions during administration of oral contrast media for CT enterography

OBJECTIVE

To compare small bowel distension and bowel wall visualization among three different patients' positions (supine, sitting and right decubitus) during administration of oral contrast media in preparation for CT enterography (CTE).

METHODS

A total of 150 consecutive patients (104 males and 46 females; mean age 34.6 years, range 15-78 years) who were scheduled to undergo CTE were recruited. Patients were randomly allocated into the three position groups during oral contrast media administration, and there were 50 patients in each group. Two blinded radiologists independently scored the luminal distension and visualization of the bowel wall using a continuous 5-point scale (1: worst and 5: best) at the jejunum and ileum. The Mann-Whitney U test was used to evaluate differences between any two groups among the three positions for bowel distension and wall visualization.

RESULTS

For ileal distension, the supine and sitting positions performed better than the right decubitus position [for reader 1, mean: 3.4/3.2/2.9 (hereafter, supine/sitting/right decubitus in order), p = 0.002/0.033; for reader 2, 3.3/3.0/2.6, p < 0.001/0.027]. However, there was no significant difference among the three groups for jejunal distension (for reader 1, 2.4/2.3/2.2; for reader 2, 2.4/2.4/2.2, p > 0.05, respectively). For bowel wall visualization, the supine and sitting positions were superior to the right decubitus position for the ileum when scored by one reader (4.0/3.8/3.4, p = 0.001/0.015).

CONCLUSION

Supine and sitting positions during the administration of oral contrast media provided better ileal distension than the right decubitus position in obtaining CTE. Advances in knowledge: The performance of CTE largely depends on adequate luminal distension and wall visualization. As the terminal ileum is the predominant site of small bowel pathology for inflammatory bowel disease, the supine or sitting position would be preferable for patients who are suspected of having small bowel pathology.

CT enterography: Mannitol versus VoLumen

INTRODUCTION

Several different neutral oral contrast agents have been trialled in magnetic resonance and CT enterography (CTE). In the Auckland region, Mannitol 2.5% and VoLumen are both used in CTE. This study compares the performance of these two neutral oral contrast agents in CTE.

METHODS

Computed tomography enterography data were collected from 25 consecutive studies that used either Mannitol or VoLumen in 2014. All images were reviewed by three radiologists blinded to the type of oral contrast. Each quadrant was assessed for maximum distension, proportion of bowel loops distended, presence of inhomogeneous content and bowel wall visibility. Assessment also included whether the contrast agent reached the caecum and an overall subjective quality assessment. Patients were invited to answer a questionnaire regarding tolerability of the preparations.

RESULTS

Mannitol achieves better wall visibility in the right upper quadrant, left upper quadrant and left lower quadrant (P < 0.01). Overall differences in study quality favours Mannitol (P < 0.01) with 48% of the Mannitol studies being considered excellent compared with 4% of the VoLumen studies. There was no difference in maximal distension or proportion of loops distended.

CONCLUSION

Mannitol in CTE achieves studies of a better quality than and is a viable alternative to VoLumen.

Diagnostic value of capsule endoscopy combined with computed tomography enterography for small intestinal diseases

AIM: To assess diagnostic value of capsule endoscopy (CE) combined with computed tomography enterography (CTE) for small bowel diseases.

METHODS: One hundred and fourteen patients with suspected small bowel diseases underwent CE and CTE examinations (interval time 2-7 d). The diagnostic accuracy for small bowel diseases was compared between CE and CTE, based on pathological or follow-up results. The diagnostic accuracy of combined CE and CTE was also estimated.

RESULTS: The symptoms of enrolled patients included obscure gastrointestinal bleeding (OGIB, 35 cases), unexplained abdominal pain (32 cases), suspected Crohn's disease (29 cases) and unexplained weight loss (18 cases). For OGIB, CE had a higher diagnostic accuracy than CTE (51.4% vs 40.0%, P < 0.05). The diagnostic accuracy reached 57.1% when the two methods were combined. For unexplained abdominal pain, diagnostic accuracy was comparable between CE and CTE (46.9% vs 40.6%, P > 0.05). The diagnostic accuracy reached 59.3% when the two methods were combined, which was higher than that of CE or CTE alone. For suspected Crohn's disease, CE had a higher diagnostic accuracy than CTE (86.2% vs 65.5%, P < 0.05). The diagnostic accuracy reached 93.1% when the two methods were combined, which was higher than that of CTE alone.

CONCLUSION: Both CE and CTE prove to be effective procedures for patients with suspected small bowel disease, but the diagnostic value of CE is higher than that of CTE for OGIB and suspected Crohn's disease. The combination of CE and CTE may be a better strategy.