Splanchnic Hemodynamics and Intestinal Vascularity in Crohn's Disease: An In Vivo Evaluation Using Doppler and Contrast-Enhanced Ultrasound and Biochemical Parameters

Basic practices for gastrointestinal ultrasound

The standard diagnostic modalities for gastrointestinal (GI) diseases have long been endoscopy and barium enema. Recently, trans-sectional imaging modalities, such as computed tomography and magnetic resonance imaging, have become increasingly utilized in daily practice. In transabdominal ultrasonography (US), the bowel sometimes interferes with the observation of abdominal organs. Additionally, the thin intestinal walls and internal gas can make structures difficult to identify. However, under optimal US equipment settings, with identification of the sonoanatomy and knowledge of the US findings of GI diseases, US can be used effectively to diagnose GI disorders. Thus, the efficacy of GIUS has been gradually recognized, and GIUS guidelines have been published by the World Federation for Ultrasound in Medicine and Biology and the European Federation of Societies for Ultrasound in Medicine and Biology. Following a systematic scanning method according to the sonoanatomy and precisely estimating the layered wall structures by employing color Doppler make diagnosing disease and evaluating the degree of inflammation possible. This review describes current GIUS practices from an equipment perspective, a procedure for systematic scanning, typical findings of the normal GI tract, and 10 diagnostic items in an attempt to help medical practitioners effectively perform GIUS and promote the use of GIUS globally.

Multispectral optoacoustic tomography of the human intestine - temporal precision and the influence of postprandial gastrointestinal blood flow

Multispectral optoacoustic tomography (MSOT) holds great promise as a non-invasive diagnostic tool for inflammatory bowel diseases. Yet, reliability and the impact of physiological processes during fasting and after food intake on optoacoustic signals have not been studied. In the present investigator initiated trial (NCT05160077) the intestines of ten healthy subjects were examined by MSOT at eight timepoints on two days, one fasting and one after food intake. While within-timepoint and within-day reproducibility were good for single wavelength 800 nm and total hemoglobin (ICC 0.722-0.956), between-day reproducibility was inferior (ICC -0.137 to 0.438). However, temporal variability was smaller than variation between individuals (coefficients of variation 8.9%-33.7% vs. 17.0%-48.5%). After food intake and consecutive increased intestinal circulation, indicated by reduced resistance index of simultaneous Doppler ultrasound, optoacoustic signals did not alter significantly. In summary, this study demonstrates high reliability and temporal stability of MSOT for imaging the human intestine during fasting and after food intake.

Altered Bioavailability and Pharmacokinetics in Crohn's Disease: Capturing Systems Parameters for PBPK to Assist with Predicting the Fate of Orally Administered Drugs

Backgrond and Objective

Crohn’s disease (CD) is a chronic inflammatory bowel disease that affects a wide age range. Hence, CD patients receive a variety of drugs over their life beyond those used for CD itself. The changes to the integrity of the intestine and its drug metabolising enzymes and transporters (DMETs) can alter the oral bioavailability of drugs. However, there are other changes in systems parameters determining the fate of drugs in CD, and understanding these is essential for dose adjustment in patients with CD.

Methods

The current analysis gathered all the available clinical data on the kinetics of drugs in CD (by March 2021), focusing on orally administered small molecule drugs. A meta-analysis of the systems parameters affecting oral drug pharmacokinetics was conducted. The systems information gathered on intestine, liver and blood proteins and other physiological parameters was incorporated into a physiologically based pharmacokinetic (PBPK) platform to create a virtual population of CD patients, with a view for guiding dose adjustment in the absence of clinical data in CD.

Results

There were no uniform trends in the reported changes in reported oral bioavailability. The nature of the drug as well as the formulation affected the direction and magnitude of variation in kinetics in CD patients relative to healthy volunteers. Even for the same drug, the reported changes in exposure varied, possibly due to a lack of distinction between the activity states of CD. The highest alteration was seen with S-verapamil and midazolam, 8.7- and 5.3-fold greater exposure, respectively, in active CD patients relative to healthy volunteers. Only one report was available on liver DMETs in CD, and indicated reduced CYP3A4 activity. In a number of reports, mRNA expression of DMETs in the ileum and colon of CD patients was measured, focussing on P-glycoprotein (p-gp) transporter and CYP3A4 enzyme, and showed contradictory results. No data were available on protein expression in duodenum and jejunum despite their dominant role in oral drug absorption.

Conclusion

There are currently inadequate dedicated clinical or quantitative proteomic studies in CD to enable predictive PBPK models with high confidence and adequate verification. The PBPK models for CD with the available systems parameters were able to capture the major physiological influencers and the gaps to be filled by future research. Quantification of DMETs in the intestine and the liver in CD is warranted, alongside well-defined clinical drug disposition studies with a number of index drugs as biomarkers of changes in DMETs in these patients, to avoid large-scale dedicated studies for every drug to determine the effects of disease on the drug’s metabolism and disposition and the consequential safety and therapeutic concerns.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40262-022-01169-4.

Initial Abdominal CT and Laboratory Findings Prior to Diagnosis of Crohn's Disease in Children

PURPOSE

To identify initial abdominal computed tomography (CT) and laboratory findings prior to a diagnosis of Crohn's disease (CD) in children.

MATERIALS AND METHODS

In this retrospective study, patients (≤18 year-old) who were diagnosed with CD from 2004 to 2019 and had abdominal CT just prior to being diagnosed with CD were included in the CD group. Patients (≤18 years old) who were diagnosed with infectious enterocolitis from 2018 to 2019 and had undergone CT prior to being diagnosed with enterocolitis were included as a control group. We assessed the diagnostic performances of initial CT and laboratory findings for the diagnosis of CD using logistic regression and the area under the curve (AUC).

RESULTS

In total, 107 patients (50 CD patients, 57 control patients) were included, without an age difference between groups (median 13 years old vs. 11 years old, p=0.119). On univariate logistic regression analysis, multisegmental bowel involvement, mesenteric vessel engorgement, higher portal vein/aorta diameter ratio, longer liver longitudinal diameter, lower hemoglobin (≤12.5 g/dL), lower albumin (≤4 g/dL), and higher platelet (>320×10³/µL) levels were significant factors for CD. On multivariate analysis, multisegmental bowel involvement [odds ratio (OR) 111.6, 95% confidence interval (CI) 4.778-2605.925] and lower albumin levels (OR 0.9, 95% CI 0.891-0.993) were significant factors. When these two features were combined, the AUC value was 0.985 with a sensitivity of 96% and specificity of 100% for differentiating CD.

CONCLUSION

Multisegmental bowel involvement on CT and decreased albumin levels can help differentiate CD from infectious enterocolitis in children prior to a definite diagnosis of CD.

Intestinal Conventional Ultrasonography, Contrast-Enhanced Ultrasonography and Magnetic Resonance Enterography in Assessment of Crohn's Disease Activity: A Comparison with Surgical Histopathology Analysis

BACKGROUND AND AIMS

Contrast-enhanced ultrasonography (CEUS) is a potential interesting method for assessing accurately Crohn's disease (CD) activity. We compared the value of intestinal ultrasonography (US) coupled with contrast agent injection with that of magnetic resonance enterography (MRE) in the assessment of small bowel CD activity using surgical histopathology analysis as reference.

METHODS

Seventeen clinically active CD patients (14 women, mean age 33 years) requiring an ileal or ileocolonic resection were prospectively enrolled. All performed a MRE and a US coupled with contrast agent injection (CEUS) less than 8 weeks prior to surgery. Various imaging qualitative and quantitative parameters were recorded and their respective performance to detect disease activity, disease extension and presence of complications was compared to surgical histopathological analysis.

RESULTS

The median wall thickness measured by US differed significantly between patients with non-severely active CD (n = 5) and those with severely active CD (n = 12) [7.0 mm, IQR (6.5-9.5) vs 10.0 mm, IQR (8.0-12.0), respectively; p = 0.03]. A non-significant trend was found with MRE with a median wall thickness in severe active CD of 10.0 mm, IQR (8.0-13.7) compared with 8.0 mm, IQR (7.5-10.5) in non-severely active CD (p = 0.07). The area under the ROC curve (AUROC) of the wall thickness assessed by US and MRE to identify patients with or without severely active CD on surgical specimens were 0.85, 95% CI (0.64-1.04), p = 0.03 and 0.80, 95% CI (0.56-1.01), p = 0.07, respectively. Among the parameters derived from the time-intensity curve during CEUS, time to peak and rise time were the two most accurate markers [AUROC = 0.88, 95% CI (0.70-1.04), p = 0.02 and 0.86, 95% CI (0.68-1.04), p = 0.03] to detect patients with severely active CD assessed on surgical specimens.

CONCLUSION

The accuracy of intestinal CEUS is close to that of conventional US to detect disease activity. A thickened bowel and shortened time to peak and rise time were the most accurate to identify CD patients with severe histological disease activity.

Crohn's Disease Activity Evaluation by Transabdominal Ultrasonography: Correlation with Double-Balloon Endoscopy

OBJECTIVES

Transabdominal ultrasonography (US) has been reported as a useful tool for evaluating Crohn's disease (CD) activity. Endoscopic findings and Crohn's disease activity index (CDAI) are currently considered the gold standard for assessing CD activity. We assessed the correlation between US and double-balloon endoscopy (DBE), and CDAI for evaluating CD activity.

METHODS

We analyzed patients with CD undergoing US and DBE within 10 days between the procedures. The intestine was divided into four segments and analyzed by the US scoring system (US-CD) and the simple endoscopic score for Crohn's disease (SES-CD). CDAI was compared with US-CD and SES-CD. Spearman's rank correlation coefficient was used for statistical analysis.

RESULTS

Twenty-five patients with CD (11 women, 14 men; mean age 35.4 ± 14.9 years, range 16-65 years) were enrolled. Twenty-four patients received antitumor necrosis factor inhibitor therapy. CDAI was 128.1 (range 36-227). A significant moderate correlation was found between the US-CD and SES-CD in all segments (ρ = .64, P < .01). The US-CD showed a strong correlation with CDAI (ρ = .78, P < .01), whereas the SES-CD showed a moderate correlation (ρ = .55, P < .05).

CONCLUSIONS

US-CD and SES-CD showed a moderate correlation for assessing CD activity. US-CD showed a stronger correlation with CDAI than SES-CD, suggesting that US could more accurately evaluate the disease activity.

Current noninvasive modalities in Crohn's disease monitoring

Crohn’s disease (CD) is characterized by a remitting and relapsing course. Longstanding active CD may result in accumulating intestinal damage and disease-related complications. In contrast, mucosal healing is associated with significant improvement in the health-related quality of life, longer periods of disease remission and lower risk of disease progression, complications, hospitalizations, intestinal surgeries, as well as a lower risk of developing colorectal cancer. Mucosal healing, the new treatment endpoint in CD, made necessary the development of noninvasive, accurate, objective and reliable tools for the evaluation of CD activity. Ileocolonoscopy with biopsies remains the reference standard method for the evaluation of the colonic and terminal ileal mucosa. However, it is an invasive procedure with a low risk of complications, allowing the investigation of only a small part of the small bowel mucosa without being able to assess transmural inflammation. These disadvantages limit its role in the frequent follow up of CD patients. In this review, we present the currently available biomarkers and imaging modalities for the noninvasive assessment of CD activity.

Bowel Sonoelastography in Patients with Crohn's Disease: A Systematic Review

Sonoelastography is an ultrasound-based method for evaluating the biological properties of a target tissue. It is commonly used in the diagnosis of liver and thyroid disease, but recently its use for monitoring the characteristics of bowel wall in patients affected by Crohn's disease (CD) has been proposed. Our aim was a systematic review of the use of sonoelastography in patients with CD. An initial database search retrieved 32 possible articles. On initial screening, 7 articles, concerning a total of 129 patients and 154 lesions of the small and large bowel, were finally included in the review. The age range varied between 6 and 53 y, and disease duration ranged between 1 and 623 mo. We collected data on the examinations performed (type and time), bowel area considered and parameters evaluated. All authors found that elastography correlates well with the degree of fibrosis, as wall strain significantly decreases in segments affected by fibrotic stenosis. Even though the endpoints proposed in the various articles are relatively inhomogeneous and scarcely comparable, we found that sonoelastography is a promising tool in the evaluation of patients with CD as it can differentiate inflammatory and fibrotic strictures in small case series.

Validity of Contrast-enhanced Ultrasonography and Dynamic Contrast-enhanced MR Enterography in the Assessment of Transmural Activity and Fibrosis in Crohn's Disease

BACKGROUND AND AIMS

Increased small intestinal wall thickness correlates with both inflammatory activity and fibrosis in Crohn's disease [CD]. Assessment of perfusion holds promise as an objective marker distinguishing between the two conditions. Our primary aim was to determine if relative bowel wall perfusion measurements correlate with histopathological scores for inflammation or fibrosis in CD.

METHODS

A total of 25 patients were investigated before elective surgery for small intestinal CD. Unenhanced ultrasonography [US] and magnetic resonance enterography [MRE] were applied to describe bowel wall thickness. Perfusion was assessed with contrast-enhanced US [CEUS] and dynamic contrast-enhanced MRE [DCE-MRE]. Histopathology was used as gold standard.

RESULTS

Compared with histopathology, the mean wall thickness was 0.4 mm greater on US [range -0.3 to 1.0, p = 0.24] and 1.4 mm greater on MR [0.4 to 2.3, p = 0.006]. No correlation was found between the severity of inflammation or fibrosis on histopathology, and either DCE-MRE [r = -0.13, p = 0.54 for inflammation and r = 0.41, p = 0.05 for fibrosis] or CEUS [r = 0.16, p = 0.45 for inflammation and r = -0.28, p = 0.19 for fibrosis]. Wall thickness assessed with US was correlated with both histological inflammation [r = 0.611, p = 0.0012] and fibrosis [r = 0.399, p = 0.048]. The same was not true for MR [r = 0.41, p = 0.047 for inflammation and r = 0.29, p = 0.16 for fibrosis].

CONCLUSIONS

Bowel wall thickness assessed with US is a valid marker of inflammation in small intestinal CD. However, relative contrast enhancement of US or of MRE cannot distinguish between inflammatory activity and fibrosis.