Active Crohn disease: CT findings and interobserver agreement for enteric phase CT enterography

Individualized small bowel preparation for computed tomography enterography: A prospective randomized controlled trial

BACKGROUND AND AIM

The study aims to evaluate the feasibility of body mass index (BMI)-based individualized small bowel preparation for computed tomography enterography (CTE).

METHODS

In this prospective randomized controlled study, patients undergoing CTE were randomly assigned to the individualized group or standardized group. Those in individualized group were given different volumes of mannitol solution based on BMI (1000 mL for patients with BMI < 18.5 kg/m2 , 1500 mL for patients with 18.5 kg/m2  ≤ BMI < 25 kg/m2 and 2000 mL for patients with BMI ≥ 25 kg/m2 ) while patients in the standardized group were all asked to consume 1500-mL mannitol solution. CTE images were reviewed by two experienced radiologists blindly. Each segment of the small bowel was assessed for small bowel image quality and disease detection rates. Patients were invited to record a diary regarding adverse events and acceptance.

RESULTS

A total of 203 patients were enrolled and randomly divided into two groups. For patients with BMI < 18.5 kg/m2 , 1000-mL mannitol solution permitted a significantly lower rate of flatulence (P = 0.045) and defecating frequency (P = 0.011) as well as higher acceptance score (P = 0.015), but did not affect bowel image quality and diseases detection compared with conventional dosage. For patients with BMI ≥ 25 kg/m2 , 2000-mL mannitol solution provided better overall image quality (P = 0.033) but comparable rates of adverse events and patients' acceptance compared with conventional dosage.

CONCLUSIONS

Individualized bowel preparation could achieve both satisfactory image quality and patients' acceptance thus might be an acceptable alternative in CTE.

Residual abnormalities on CTE predict adverse outcomes in Crohn's disease with endoscopic healing

BACKGROUND

Residual abnormalities on computed tomography enterography (CTE) in Crohn's disease (CD) with endoscopic healing (EH) may have prognostic implications and affect therapeutic strategy.

METHODS

CD patients with EH who underwent CTE between March 2015 and June 2022 were enrolled. CTE findings of the terminal ileum and the most severe segment of colon at the time of EH were assessed respectively for each patient. Cox regression analysis and Kaplan-Meier curves were used to evaluate the association between residual abnormalities and adverse outcomes.

RESULTS

A total of 140 patients (217 digestive segments) were included. Mesenteric edema (hazard ratio [HR] = 3.61, 95% CI = 1.81-7.20, P<0.001), fibrofatty proliferation (HR = 3.40, 95% CI = 1.97-5.85, P<0.001) and active small bowel inflammation (HR = 2.74, 95% CI = 1.59-4.71, P<0.001) were risk factors for clinical relapse. Furthermore, we built a scoring system using the three parameters. Radiologic score ≥ 1 was the best threshold to predict clinical relapse (HR = 4.56, 95% CI = 2.54-8.19, P<0.001) and it was validated in different outcomes.

CONCLUSION

The scoring system based on three residual abnormalities on CTE can predict adverse outcomes in CD patients with EH.

Mesenteric creeping fat index defined by CT enterography is associated with early postoperative recurrence in patients with Crohn's disease

OBJECTIVES

To investigate the value of mesenteric creeping fat index (MCFI) defined by computed-tomography enterography (CTE) in patients with Crohn's Disease (CD) for predicting early postoperative recurrence.

METHODS

A total of 110 patients with CD who underwent CTE and I-stage intestinal resection surgery from December 2013 to December 2018 were enrolled. Two radiologists independently assessed CTE parameters, including MCFI, with scores ranging from 1 to 8; bowel-wall thickening, with a scale of 1 to 3; mural hyperenhancement, mural stratification, submucosal fat deposition, mesenteric fibrofatty proliferation, mesenteric hypervascularity, mesenteric fat stranding, with a scale of 0 to 2; abscess/fistula, enlarged mesenteric lymph node, abdominal and pelvic effusion, with a scale of 0 to 1. Imaging findings associated with early recurrence were assessed using logistic regression analysis.

RESULTS

Within one year follow-up, early postoperative recurrence occurred in 56.4 % (62/110) patients with CD. In univariate analysis, MCFI, bowel-wall thickening, mesenteric hypervascularity, mesenteric fat stranding, abscess/fistula and mesenteric lymphadenopathy were associated with early postoperative recurrence. Among all variables, MCFI (score ≥ 4) contributes the optimal AUC (0.838 [0.758-0.919]), specificity (89.6 %), positive predictive value (90.7 %), accuracy (83.6 %), and risk ratio (OR = 32.42 [10.69-98.33], p < 0.001). In multivariate analysis, only MCFI was an independent predictor of early postoperative recurrence (OR = 25.71 [7.65-86.35], p < 0.001).

CONCLUSION

CTE features are useful in predicting early postoperative recurrence in patients with CD, MCFI may be a valuable tool for clinical monitoring and follow-up.

Imaging of Gastrointestinal Tract Ailments

Gastrointestinal (GI) disorders comprise a diverse range of conditions that can significantly reduce the quality of life and can even be life-threatening in serious cases. The development of accurate and rapid detection approaches is of essential importance for early diagnosis and timely management of GI diseases. This review mainly focuses on the imaging of several representative gastrointestinal ailments, such as inflammatory bowel disease, tumors, appendicitis, Meckel's diverticulum, and others. Various imaging modalities commonly used for the gastrointestinal tract, including magnetic resonance imaging (MRI), positron emission tomography (PET) and single photon emission computed tomography (SPECT), and photoacoustic tomography (PAT) and multimodal imaging with mode overlap are summarized. These achievements in single and multimodal imaging provide useful guidance for improved diagnosis, staging, and treatment of the corresponding gastrointestinal diseases. The review evaluates the strengths and weaknesses of different imaging techniques and summarizes the development of imaging techniques used for diagnosing gastrointestinal ailments.

Crohn's disease active inflammation assessment with iodine density from dual-energy CT enterography: comparison with endoscopy and conventional interpretation

PURPOSE

To compare terminal ileum (TI) mucosal iodine density obtained at dual-energy CT enterography (DECTE) with conventional CT interpretation and endoscopy in patients with Crohn's disease (CD).

MATERIALS AND METHODS

Twenty-three CD patients (14 men; mean[SD] age:48.1[16.7] years) with endoscopy within 30 days of DECTE were retrospectively identified. An inflammatory bowel disease gastroenterologist reviewed endoscopic images. Two radiologists qualitatively assessed the presence of active TI inflammation. Mean iodine density normalized to the aorta (I%), mean absolute iodine density (I), and iodine density standard deviation (I_SD) from the distal 2 cm ileum (TI) mucosa obtained using semiautomatic prototype software were compared with endoscopic assessment using Mann Whitney tests. The optimal threshold I% and I were determined from receiver operating curves (ROC). Sensitivity and specificity of conventional interpretation and determined iodine thresholds were compared using McNemar's test. Inter-reader agreement was assessed using kappa. A p < 0.05 indicated statistical significance.

RESULTS

Twelve (52.1%) patients had endoscopic active inflammation. I% was 37.9[13.3]% for patients with and 21.7[7.5]% for patients without endoscopic active inflammation (p = 0.001). The optimal ROC threshold 24.6% had 100% sensitivity and 81.8% specificity (AUC = 0.909, 95% CI 0.777-1). I was 2.44[0.73]mg/mL for patients with and 1.77[1.00]mg/mL for patients without active endoscopic inflammation (p = 0.0455). The optimal ROC threshold 1.78 mg/mL I had 91.7% sensitivity and 63.6% specificity (AUC = 0.75, 95% CI 0.532-0.968). I_SD was similar for patients with and without endoscopic active inflammation (0.82[0.33]mg/mL and 0.77[0.28]mg/mL, respectively, p = 0.37). Conventional interpretation sensitivity and specificity (R1/R2) were 83.3%/91.7% and 72.7%/54.5%, respectively (all p > 0.05) with moderate inter-reader agreement (Κ = 0.542[95% CI 0.0202-0.088]).

CONCLUSION

Mean normalized iodine density is highly sensitive and specific for endoscopic active inflammation. DECTE could be considered as a surrogate to endoscopy in CD patients. Despite trends towards improved sensitivity and specificity compared with conventional interpretation, future larger studies are needed.

Bleeding per rectum in pediatric population: A pictorial review

Bleeding per rectum in children can be seen in congenital as well as acquired conditions that may require medical or surgical management. The present review article is aimed to discuss the imaging findings of some common and uncommon causes of bleeding per rectum in children.

Bleeding per rectum in pediatric population: A pictorial review

Bleeding per rectum in children can be seen in congenital as well as acquired conditions that may require medical or surgical management. The present review article is aimed to discuss the imaging findings of some common and uncommon causes of bleeding per rectum in children.

Efficiency of dual-energy computed tomography enterography in the diagnosis of Crohn's disease

Background

This retrospective study aimed to investigate the usefulness of the optimized kiloelectron volt (keV) for virtual monoenergetic imaging (VMI) combined with iodine map in dual-energy computed tomography enterography (DECTE) in the diagnosis of Crohn’s disease (CD).

Methods

Seventy-two patients (mean age: 41.89 ± 17.28 years) with negative computed tomography enterography (CTE) were enrolled for investigating the optimized VMI keV in DECTE by comparing subjective and objective parameters of VMIs that were reconstructed from 40 to 90 keV. Moreover, 68 patients (38.27 ± 15.10 years; 35 normal and 33 CD) were included for evaluating the diagnostic efficacy of DECTE iodine map at the optimized VMI energy level and routine CTE for CD and active CD. Statistical analysis for all data was conducted.

Results

Objective and subjective imaging evaluations showed the best results at 60 keV for VMIs. The CT values of the normal group, active subgroup, and CD group during the small intestinal phase at routine 120 kVp or 60 keV VMI had significant differences. The diagnostic efficacy of an iodine map was the best when NIC = 4% or fat value = 45.8% for CD, whereas NIC < 0.35 or the fat value < 0.38 for active CD. The combined routine CTE and optimized VMI improved the diagnostic efficacy (P < 0.001).

Conclusions

VMI at 60 keV provided the best imaging quality on DECTE. NIC and fat value provided important basis for active CD evaluation. Routine CTE combined with VMI at 60 keV improved the diagnostic efficiency for CD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12880-021-00716-y.

Tailored versus fixed scan delay in contrast-enhanced abdominal multi-detector CT: An intra-patient comparison of image quality

PURPOSE

To perform anintra-patient comparison betweena single-pass protocol (SP) and a portal venous phase (PVP) by means ofboth quantitative and qualitative analysis of image quality.

METHODS

Forty patients (31 M; 9F; aged 20-77 years; BMI 23 ± 4 Kg/m²) underwent both a SP and a PVP using a 64-rows multi-detector CT with a median interval time of 56 days (range5-903). All patients underwent i.v. bolus injection (2.0 cc/sec) of 1.7 cc/Kg of a non ionic iodinated contrast-media (370 mgI/ml) with scan delays of 67 ± 8 and 90 s for the SP and the PVP, respectively. Signal- (SNR) and contrast-to-noise ratios (CNR) were calculated for most visceral organs and for both abdominal aorta (AA) and main portal vein (MPV). For qualitative analysis, reproduction of abdominal viscera and vascular structures was blindly evaluated and inter-observer agreement calculated by the weighted Cohen k-analysis.

RESULTS

Attenuation values (H.U.) of AA (232 ± 53vs180 ± 36) and MPV (215 ± 39vs187 ± 42) were significantly (p < 0.001) higher in the SP than in PVP, respectively. At qualitative analysis, reproduction of mostabdominal viscerawas also significantly sharper (p < 0.001) with the SP than the PVPwith inter-observer agreement scores (k)ranging from 0.60 to 0.88 for all but one imaging criteria.

CONCLUSIONS

As the SP resulted in a significantly higher vascular enhancement and in a sharper reproduction of most abdominal viscera, it may be better suited than a PVP for the CT evaluation of non traumatic acute abdomen.

Crohn Disease Active Inflammation Assessment with Iodine Density from Dual-Energy CT Enterography: Comparison with Histopathologic Analysis

Background Dual-energy CT enterography (DECTE) has been shown to be useful in characterizing Crohn disease activity compared with clinical markers of inflammation but, to the knowledge of the authors, comparison has not been made with histopathologic specimens. Purpose To compare mucosal iodine density obtained at DECTE from Crohn disease-affected bowel with histopathologic specimens from surgically resected ileocolectomy bowel segments or terminal ileum colonoscopic biopsies in the same patients. Materials and Methods This was a retrospective study. Bowel segments in adults with Crohn disease who underwent DECTE from January 2017 to April 2019 within 90 days of ileocolectomy or colonoscopy were retrospectively evaluated with prototype software allowing the semiautomatic determination of inner hyperdense bowel wall (mucosal) mean iodine density, normalized to the aorta. Mean normalized iodine density and clinical activity indexes (Crohn Disease Activity Index [CDAI] and Harvey-Bradshaw Index [HBI]) were compared with histologic active inflammation grades by using two-tailed t tests. Receiver operating characteristic curves were generated for mean normalized iodine density, CDAI, and HBI to determine sensitivity, specificity, and accuracy. A P value less than .05 was considered to indicate statistical significance. Results The following 16 patients were evaluated (mean age, 41 years ± 14 [standard deviation]): 10 patients (five men, five women; mean age, 41 years ± 15) with 19 surgical resection specimens and six patients with terminal ileum colonoscopic mucosal biopsies (four men, two women; mean age, 43 years ± 14). Mean normalized iodine density was 16.5% ± 5.7 for bowel segments with no active inflammation (n = 8) and 34.7% ± 9.7 for segments with any active inflammation (n = 17; P < .001). A 20% mean normalized iodine density threshold had sensitivity, specificity, and accuracy of 17 of 17 (100%; 95% CI: 80.5, 100), six of eight (75%; 95% CI: 35, 97), and 23 of 25 (92%; 95% CI: 74, 99), respectively, for active inflammation. Clinical indexes were similar for patients with and without active inflammation at histopathologic analysis (CDAI score, 261 vs 251, respectively [P = .77]; HBI score, 7.8 vs 6.4, respectively [P = .36]). Conclusion Iodine density from dual-energy CT enterography may be used as a radiologic marker of Crohn disease activity as correlated with histopathologic analysis. © RSNA, 2021 See also the editorial by Ohliger in this issue.

FDG-PET-CT Enterography Helps Determine Clinical Significance of Suspected Ileocecal Thickening: A Prospective Study

BACKGROUND

Ileocecal thickening (ICT) on imaging could result from diverse etiologies but may also be clinically insignificant.

AIM

Evaluation of role of combined 2-deoxy-2-fluorine-18-fluoro-D-glucose(¹⁸F-FDG)-positron emission tomography and computed tomographic enterography (PET-CTE) for determination of clinical significance of suspected ICT.

METHODS

This prospective study enrolled consecutive patients with suspected ICT on ultrasound. Patients were evaluated with PET-CTE and colonoscopy. The patients were divided into: Group A (clinically significant diagnosis) or Group B (clinically insignificant diagnosis) and compared for various clinical and radiological findings. The two groups were compared for maximum standardized uptake values of terminal ileum, ileo-cecal valve, cecum and overall.

RESULTS

Of 34 patients included (23 males, mean age: 40.44 ± 15.40 years), 12 (35.3%) had intestinal tuberculosis, 11 (32.4%) Crohn's disease, 3 (8.8%) other infections, 1 (2.9%) malignancy, 4 (11.8%) non-specific terminal ileitis while 3 (8.8%) had normal colonoscopy and histology. The maximum standardized uptake value of the ileocecal area overall (SUVmax-ICT-overall) was significantly higher in Group A (7.16 ± 4.38) when compared to Group B (3.62 ± 9.50, P = 0.003). A cut-off of 4.50 for SUVmax-ICT-overall had a sensitivity of 70.37% and a specificity of 100% for prediction of clinically significant diagnosis. Using decision tree model, the SUVmax-ICT with a cut-off of 4.75 was considered appropriate for initial decision followed by the presence of mural thickening in the next node.

CONCLUSION

PET-CTE can help in discrimination of clinically significant and insignificant diagnosis. It may help guide the need for colonoscopy in patients suspected to have ICT on CT.

Crohn Disease Prognostication With Semiautomatic Dual-Energy Computed Tomography Enterography-Derived Iodine Density

OBJECTIVE

The objective of this study was to determine if dual-energy computed tomography enterography (DECTE)-obtained iodine density can predict medical management change or surgery in Crohn disease patients.

METHODS

The most active-appearing bowel segment on DECTE in 21 Crohn disease patients was retrospectively interrogated with prototype software determining the percentage of bowel wall (I) in specified ranges. Patients were categorized into 3 groups after DECTE: (1) no management change, (2) outpatient medication change, and (3) inpatient admission or surgery. Crohn's disease activity index was calculated. Group 3's percentage iodine density of >3 mg/mL and Crohn's disease activity index were compared with group 1/2. Crohn's disease activity index and percentage iodine density of >2 mg/mL were compared for groups 2/3 versus group 1 patients.

RESULTS

There were 5 group 1, 6 group 2, and 10 group 3 patients. Group 3 patients had higher frequency of iodine density >3 mg/mL (27%) compared with groups 1/2 patients (12.6%) (P < 0.05). Crohn's disease activity index was similar (P = 0.98). Groups 2/3 patients had 60.5% iodine density of >2 mg/mL, whereas group 1 patients had 31.7% iodine density of >2 mg/mL (P < 0.05). Crohn's disease activity index was similar (P = 0.12).

CONCLUSIONS

Iodine density from DECTE may predict medical or surgical Crohn disease management.

State of the Art MR Enterography Technique

ABSTRACT

Magnetic resonance enterography (MRE) is a well-established imaging technique that is commonly used for evaluating a variety of bowel diseases, most commonly inflammatory bowel disease which is increasing in prevalence. Inflammatory bowel disease is composed of 2 related, but distinct disease entities: Crohn disease (CD) and ulcerative colitis. In ulcerative colitis, inflammation is generally limited to the mucosa and invariably involves the rectum, and often the more proximal colon. CD is typified by transmural inflammation with skip lesions occurring anywhere from the mouth to anus, but characteristically involves the terminal ileum. The transmural involvement of CD may lead to debilitating ulceration and, ultimately, development of sinus tracts, which can be associated with abscesses and fistulae as extraenteric manifestations of the disease. Because much of the small bowel and extraenteric disease cannot be adequately assessed with conventional endoscopy, imaging plays a crucial role in initial diagnosis and follow-up. MRE does not use ionizing radiation which is important for these patients, many of which present earlier in life and may require multiple imaging examinations. In this article, we review the clinical indications, patient preparation, and optimal technique for MRE. We also discuss the role and proper selection of intravenous gadolinium-based contrast material, oral contrast material, and antiperistaltic agents, including pediatric considerations. Finally, we review the recommended and optional pulse sequence selection, including discussion of a "time-efficient" protocol, reviewing their utility, advantages, and limitations. Our hope is to aid the radiologist seeking to develop a robust MRE imaging program for the evaluation of bowel disease.

A Reliability Study: Strong Inter-Observer Agreement of an Expert Panel for Intestinal Ultrasound in Ulcerative Colitis

BACKGROUND

Intestinal ultrasound [IUS] is a promising and non-invasive cross-sectional imaging modality in the diagnosis and monitoring of ulcerative colitis [UC]. Unlike endoscopy, where standardized scoring for evaluation of disease activity is widely used, scoring for UC with IUS is currently unavailable. Therefore, we conducted a study to assess the reliability of IUS in UC among expert sonographists in order to identify robust parameters.

METHODS

Thirty patients with both clinically active [25] and quiescent [five] UC were included. Six expert sonographers first agreed upon key IUS parameters and grading, including bowel wall thickness [BWT], colour Doppler signal [CDS], inflammatory fat [i-fat], loss of bowel wall stratification [BWS], loss of haustrations and presence of lymph nodes. Thirty video-recorded cases were blindly reviewed.

RESULTS

Inter-observer agreement was almost perfect for BWT (intra-class correlation coefficient [ICC]: 0.96) and substantial for CDS [κ = 0.63]. Agreement was moderate for presence of lymph nodes [κ = 0.41] and fair for presence of i-fat [κ = 0.36], BWS [κ = 0.24] and loss of haustrations [κ = 0.26]. Furthermore, there was substantial agreement for presence of disease activity on IUS [κ = 0.77] and almost perfect agreement for disease severity [ICC: 0.93]. Most individual parameters showed a strong association with IUS disease activity as measured by the six readers.

CONCLUSION

IUS is a reliable imaging modality to assess disease activity and severity in UC. Important individual parameters such as BWT and CDS are reliable and could be incorporated in a future UC scoring index. Standardized acquisition and assessment of UC utilizing IUS with established reliability is important to expand the use of IUS globally.

Dual-energy CT enterography in evaluation of Crohn's disease: the role of virtual monochromatic images

PURPOSE

To assess the use of virtual monochromatic images (VMI) for discrimination of affected and non-affected bowel walls in patients with Crohn's disease (CD) as well as to compare mural enhancement between patients with and without CD.

MATERIALS AND METHODS

This retrospective study included 61 patients (47 with CD, 14 without CD). Attenuation value (AV), signal-to noise ratio (SNR), and contrast-to-noise ratio (CNR) were obtained at VMI energy levels from 40 to 110 keV in 10 keV increment. Analyses were performed among affected and non-affected bowel walls in CD patients, as well as from bowel walls in patients without CD. Image quality and mural enhancement were evaluated at VMI energy levels at 40, 70, and 110 keV.

RESULTS

At all energy levels of VMI, each quantitative data for AV, SNR, and CNR showed statistically significant difference between diseased and non-diseased bowel walls in CD patients. In the quantitative assessment of patients with and without CD, the optimal AV and SNR were obtained at 40 keV, and the optimal CNR was obtained at 70 keV. For the qualitative assessment, the best image quality and mural enhancement were obtained at 70 keV and 40 keV, respectively.

CONCLUSION

VMI are helpful for the differentiation of affected bowel walls in CD patients, providing high diagnostic accuracy.

Novel Dual-Energy Computed Tomography Enterography Iodine Density Maps Provide Unique Depiction of Crohn Disease Activity

OBJECTIVE

To create a map of iodine densities within affected segments of small-bowel Crohn disease (CD) derived from contrast-enhanced dual-energy computed tomography enterography (DECTE) studies.

METHODS

Twenty CD patients imaged with intravenous contrast-enhanced DECTE between June 2016 and December 2017 were retrospectively identified. Ten patients without clinical evidence of CD and 8 normal-appearing jejunal segments in CD patients were controls. Using prototype software, 8 manual contours were drawn along the mucosa of affected segments. Relatively normal-appearing bowel was included at the edges. These contours served as a basis for iodine density calculation and 3-dimensional iodine density map rendering. Color-coded iodine densities allowed detection and quantification of the most and least dense portion of each segment and also permitted relative comparison between segments.

RESULTS

The average iodine density per CD involved segment ranged 1.0 to 3.3 mg/mL, which differed significantly from normal ileum (P < 0.0001) and normal-appearing jejunum in patients with CD (P = 0.0009). Standard deviations ranged from 0.8 to 1.7 mg/mL, which differed significantly from normal ileum (P = 0.0039) and normal-appearing jejunum in patients with CD (P = 0.0056). The amplitude of the power spectrum ranged from 0.66 to 3.3 demonstrating patches of iodine rather than uniform distribution. This differed significantly from normal ileum (P = 0.0005) and normal-appearing jejunum in patients with CD (P = 0.0004).

CONCLUSIONS

Heterogeneous CD activity and distribution can be displayed as iodine density maps created from DECTE.

ACR Appropriateness Criteria® Crohn Disease

Three common clinical scenarios involving use of imaging in Crohn disease are covered. These include the initial evaluation of Crohn disease when the diagnosis has not been previously established, the evaluation for anticipated exacerbation of known disease, and the evaluation of disease activity during therapy monitoring. The appropriateness of a given imaging modality for each scenario is rated as one of three categories (usually appropriate, may be appropriate, usually not appropriate) to help guide evaluation. Pediatric presentation of Crohn disease and the appropriateness of imaging are not covered in this document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Evaluation of the performance of two neutral oral contrast agents in computed tomography enterography: A randomized controlled trial

OBJECTIVE

To compare the performances, tolerability and acceptability of mannitol and polyethylene glycol (PEG) as oral contrast agents in patients undergoing computed tomography enterography (CTE).

METHODS

Patients aged 18-75 years indicated for CTE were randomized to receive either mannitol or PEG as contrast agents. The coronal reconstructed images of each abdominal quadrant were assessed for maximum distention, proportion of distended bowel loops, presence of inhomogeneous contents and visibility of the small bowel wall. Overall subjective imaging quality assessment and patients' tolerability and acceptability were recorded.

RESULTS

Seventy patients were enrolled and randomized into two groups. In the per-protocol analysis, no significant differences in imaging quality was found in bowel distention maximum diameter, wall visibility and intestinal homogeneity (all P > 0.05). The mean nausea score was lower in the mannitol group (0 [0-0] vs 1.0 [0-3.0], P < 0.001). Mannitol was superior to PEG in taste (9.0 [8.0-10.0] vs 7.0 [5.0-8.0], P < 0.001), patients' willingness to reuse the drug (9.0 [8.0-10.0] vs 8.0 [7.0-9.0], P = 0.036), satisfaction (9.0 [8.0-10.0] vs 8.0 [7.0-9.0], P = 0.022) and ease of completion (9.0 [8.0-9.3] vs 8.0 [6.5-9.0], P = 0.030).

CONCLUSIONS

Both mannitol and PEG provided good bowel distention and visualization of the bowel wall. However, mannitol was significantly superior to PEG in patients' tolerability and acceptability.

Indian guidelines on imaging of the small intestine in Crohn's disease: A joint Indian Society of Gastroenterology and Indian Radiology and Imaging Association consensus statement

The Indian Society of Gastroenterology (ISG) Task Force on Inflammatory Bowel Disease and the Indian Radiological and Imaging Association (IRIA) developed combined ISG-IRIA evidence-based best-practice guidelines for imaging of the small intestine in patients suspected to have or having Crohn's disease. The 29 consensus statements, developed through a modified Delphi process, are intended to serve as reference for teaching, clinical practice, and research.

Multi-detector CT enterography in active inflammatory bowel disease: Image quality and diagnostic efficacy of a low-radiation high contrast protocol

PURPOSE

To prospectively evaluate image quality and diagnostic efficacy of a low radiation-high contrast (LR-HC) CT Enterography (CTE) in active Inflammatory Bowel Disease (IBD).

MATERIALS AND METHODS

Eighty-five (36M; 49F; 17-75 yrs) patients with active IBD underwent contrast-enhanced CTE and were stratified in two groups according to age (< or ≥45 yrs): Group A (N = 45; 32 ± 9 yrs; 58 ± 10 kg) and Group B (N = 40; 58 ± 10 yrs; 61 ± 13 kg). Each group received a different amount of radiation (Noise Index, NI) and non-ionic iodinated contrast media (LOCM) as follows: Group A (NI = 15; 2.5 ml/kg) and Group B (NI = 12.5; 2 ml/kg). Thyroid functional tests were performed in all patients of group A at 4-6 wks. Signal- and contrast-to-noise ratios were calculated for liver (L) and abdominal aorta (A). Statistical analysis was performed by Student's t- or Chi-square test for continuous and categorical data, respectively.

RESULTS

No patient of Group A developed signs of thyrotoxicosis. SNR_L, CNR_L and diagnostic accuracy of CTE were 8.4 ± 1.7 vs 8.9 ± 2.1 (p = 0.256), 5.4 ± 1.5 vs 5.6 ± 1.7 (p = 0.486) and 91.1 vs 92.5% (p = 0.764) whereas the effective dose and the LOCM administered were 6.7 ± 2.2 vs 13.9 ± 6.0 mSv (p < 0.001) and 144 ± 25 vs 122 ± 25 ml (p < 0.001) for Group A and B, respectively.

CONCLUSION

LR-HC CTE is a dose-effective protocol in the evaluation of active IBD in young patients.

Inter-radiologist agreement using Society of Abdominal Radiology-American Gastroenterological Association (SAR-AGA) consensus nomenclature for reporting CT and MR enterography in children and young adults with small bowel Crohn disease

PURPOSE

To assess inter-radiologist agreement using the Society of Abdominal Radiology-American Gastroenterological Association (SAR-AGA) consensus recommendations for reporting CT/MR enterography exams in pediatric and young adult small bowel Crohn disease (CD).

METHODS

Institutional review board approval was obtained for this HIPAA-compliant retrospective investigation; the requirement for informed consent was waived. 25 CT and 25 MR enterography exams performed in children and young adults (age range: 6-23 years) between January 2015 and April 2017 with a distribution of ileal CD severity (phenotype) were identified: normal or chronic CD without active inflammation (40%), active inflammatory CD (20%), stricturing CD (20%), and penetrating CD (20%). Five fellowship-trained pediatric radiologists, blinded to one another, documented key imaging findings and standardized impressions based on SAR-AGA consensus recommendations. Inter-radiologist agreement was evaluated using Fleiss' multi-rater kappa statistic (κ) with 95% confidence intervals (CI).

RESULTS

Inter-radiologist agreement was moderate for all key imaging findings except presence of ulcerations (κ 0.37 [95% CI 0.28-0.46]) and sacculations (κ 0.31 [95% CI 0.23-0.40]). Agreement for standardized impressions was substantial for stricturing disease (κ 0.79 [95% CI 0.70-0.87]) and moderate for presence of inflammation (κ 0.49 [95% CI 0.44-0.56]) and penetrating disease (κ 0.58 [95% CI 0.49-0.67]). No significant difference in agreement was found between CT and MRI.

CONCLUSIONS

Agreement among five pediatric radiologists was moderate to substantial for SAR-AGA standardized impressions and fair to moderate for key imaging findings of pediatric and young adult CD.

Intestinal fibrosis

Extensive tissue fibrosis is the end-stage process of a number of chronic conditions affecting the gastrointestinal tract, including inflammatory bowel disease (Crohn's disease, ulcerative colitis), ulcerative jejunoileitis, and radiation enteritis. Fibrogenesis is a physiological, reparative process that may become harmful as a consequence of the persistence of a noxious agent, after an excessive duration of the healing process. In this case, after replacement of dead or injured cells, fibrogenesis continues to substitute normal parenchymal tissue with fibrous connective tissue, leading to uncontrolled scar formation and, ultimately, permanent organ damage, loss of function, and/or strictures. Several mechanisms have been implicated in sustaining the fibrogenic process. Despite their obvious etiological and clinical distinctions, most of the above-mentioned fibrotic disorders have in common a persistent inflammatory stimulus which sustains the production of growth factors, proteolytic enzymes, and pro-fibrogenic cytokines that activate both non-immune (i.e., myofibroblasts, fibroblasts) and immune (i.e., monocytes, macrophages, T-cells) cells, the interactions of which are crucial in the progressive tissue remodeling and destroy. Here we summarize the current status of knowledge regarding the mechanisms implicated in gut fibrosis with a clinical approach, also focusing on possible targets of antifibrogenic therapies.

Iodine Quantification on Spectral Detector-Based Dual-Energy CT Enterography: Correlation with Crohn's Disease Activity Index and External Validation

Objective

To correlate CT parameters on detector-based dual-energy CT enterography (DECTE) with Crohn's disease activity index (CDAI) and externally validate quantitative CT parameters.

Materials and Methods

Thirty-nine patients with CD were retrospectively enrolled. Two radiologists reviewed DECTE images by consensus for qualitative and quantitative CT features. CT attenuation and iodine concentration for the diseased bowel were also measured. Univariate statistical tests were used to evaluate whether there was a significant difference in CTE features between remission and active groups, on the basis of the CDAI score. Pearson's correlation test and multiple linear regression analyses were used to assess the correlation between quantitative CT parameters and CDAI. For external validation, an additional 33 consecutive patients were recruited. The correlation and concordance rate were calculated between real and estimated CDAI.

Results

There were significant differences between remission and active groups in the bowel enhancement pattern, subjective degree of enhancement, mesenteric fat infiltration, comb sign, and obstruction (p < 0.05). Significant correlations were found between CDAI and quantitative CT parameters, including number of lesions (correlation coefficient, r = 0.573), bowel wall thickness (r = 0.477), iodine concentration (r = 0.744), and relative degree of enhancement (r = 0.541; p < 0.05). Iodine concentration remained the sole independent variable associated with CDAI in multivariate analysis (p = 0.001). The linear regression equation for CDAI (y) and iodine concentration (x) was y = 53.549x + 55.111. For validation patients, a significant correlation (r = 0.925; p < 0.001) and high concordance rate (87.9%, 29/33) were observed between real and estimated CDAIs.

Conclusion

Iodine concentration, measured on detector-based DECTE, represents a convenient and reproducible biomarker to monitor disease activity in CD.

Comparison of diagnostic performance between 1 millisievert CT enterography and half-standard dose CT enterography for evaluating active inflammation in patients with Crohn's disease

PURPOSE

To compare the diagnostic performance of CT enterography (CTE) images obtained at 1 millisievert (mSv) and reconstructed with filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR) with those of half-dose CTE images for the evaluation of active inflammation in patients with Crohn's disease.

METHODS

Forty-six consecutive patients (mean age 29 years; range 15-59 years) with Crohn's disease underwent CTE which comprised a standard-dose scan at the enteric phase (45 s), a half-dose scan with ASIR at the portal venous phase (70 s), and 1 mSv scans with FBP and ASIR at the delayed phase (90 s) under a fixed 120 kVp and variable mAs. Two blinded readers independently recorded confidence scores for active inflammation in the ileum and terminal ileum, respectively. The diagnostic performance of each image set was compared by pairwise comparison of receiver operating characteristic curves. The established image findings on standard-dose scan and ileocolonoscopy served as the reference standard.

RESULTS

A total of 92 bowel segments were analyzed. For reader 1, the diagnostic performance was increased from 1 mSv CT with FBP and 1 mSv CT with ASIR to half-dose scan with ASIR (AUC, 0.759, 0.794, and 0.845; P = 0.1429, P = 0.0107, respectively). For reader 2, there was no significant difference among the three image sets (AUC, 0.848, 0.865, and 0.845; P > 0.05, respectively).

CONCLUSIONS

The diagnostic performance of 1 mSv CTE may be comparable to that of half-dose CTE.

Clinical Benefit of Capsule Endoscopy in Crohn's Disease: Impact on Patient Management and Prevalence of Proximal Small Bowel Involvement

BACKGROUND

Ileocolonoscopy and computed tomography (CT) or magnetic resonance (MR) enterography (CTE/MRE) are utilized to evaluate patients with small bowel (SB) Crohn's disease (CD). The purpose of our study was to estimate the impact of capsule endoscopy (CE) on patient management after clinical assessment, ileocolonoscopy, and CTE/MRE.

METHODS

We prospectively analyzed 50 adult CD patients without strictures at clinically indicated ileocolonoscopy and CTE/MRE exams. Providers completed pre- and post-CE clinical management questionnaires. Pre-CE questionnaire assessed likelihood of active SBCD and management plan using a 5-point level of confidence (LOC) scales. Post-CE questionnaire assessed alteration in management plans and contribution of CE findings to these changes. A change of ≥2 on LOC scale was considered clinically meaningful.

RESULTS

Of the 50 patients evaluated (60% females), median age was 38 years, median disease duration was 3 years, and median Crohn's Disease Activity Index (CDAI) score was 238 points. All CTE/MRE studies were negative for proximal disease. CE detected proximal disease in 14 patients (28%) with a median Lewis score of 215 points. CE findings altered management in 17 cases (34%). The most frequent provider-perceived benefits of CE were addition of new medication (29%) and exclusion of active SB mucosal disease (24%).

CONCLUSION

CE is a safe imaging modality that alters clinical management in patients with established SBCD by adding incremental information not available at ileocolonoscopy and cross-sectional enterography.

Value of dual-energy CT enterography in the analysis of pathological bowel segments in patients with Crohn's disease

OBJECTIVE

To analyze whether there are significant differences in the objective quantitative parameters obtained in the postprocessing of dual-energy CT enterography studies between bowel segments with radiologic signs of Crohn's disease and radiologically normal segments.

MATERIAL AND METHODS

This retrospective study analyzed 33 patients (16 men and 17 women; mean age 54 years) with known Crohn's disease who underwent CT enterography on a dual-energy scanner with oral sorbitol and intravenous contrast material in the portal phase. Images obtained with dual energy were postprocessed to obtain color maps (iodine maps). For each patient, regions of interest were traced on these color maps and the density of iodine (mg/ml) and the fat fraction (%) were calculated for the wall of a pathologic bowel segment with radiologic signs of Crohn's disease and for the wall of a healthy bowel segment; the differences in these parameters between the two segments were analyzed.

RESULTS

The density of iodine was lower in the radiologically normal segments than in the pathologic segments [1.8 ± 0.4mg/ml vs. 3.7 ± 0.9mg/ml; p<0.05]. The fat fraction was higher in the radiologically normal segments than in the pathologic segments [32.42% ± 6.5 vs. 22.23% ± 9.4; p<0.05].

CONCLUSION

There are significant differences in the iodine density and fat fraction between bowel segments with radiologic signs of Crohn's disease and radiologically normal segments.

Prospective Comparison of Standard- Versus Low-Radiation-Dose CT Enterography for the Quantitative Assessment of Crohn Disease

OBJECTIVE

CT enterography (CTE) is sensitive and specific for active inflammatory changes of Crohn disease (CD), but its use has been limited by exposure to ionizing radiation. The objective of this study is to show the noninferiority of a model-based iterative reconstruction (MBIR) technique using lower radiation doses compared with standard-dose CTE in the assessment of CD.

SUBJECTS AND METHODS

Patients referred to a hospital radiology department for CTE for the evaluation of CD underwent both a standard examination (used to generate filtered back-projection and adaptive statistical iterative reconstruction [ASIR] images) and low-dose MBIR CTE performed in a random sequence on the same day. Images were reviewed by two radiologists for signs of small-bowel CD. Radiologic findings obtained using ASIR and clinical assessments of disease activity served as the reference standard for comparison with low-dose CTE findings.

RESULTS

A total of 163 patients, 92 (56.4%) of whom had active disease, underwent CTE. MBIR was found to be noninferior to the two standard-dose techniques, with no significant differences noted between the three types of images when compared with the clinical reference standard. As compared with the radiologic standard of ASIR, the very-low-dose scans had a high degree of accuracy, with sensitivity ranging from 0.85 to 0.94 and specificity ranging from 0.84 to 0.97 depending on the reader. A significant reduction in radiation exposure was noted with MBIR (mean [± SD] reduction, 3.30 ± 3.17 mSv) versus standard-dose imaging (7.16 ± 4.61 mSv; p < 0.001).

CONCLUSION

Low-dose CTE using MBIR is sensitive and specific for the detection of active inflammatory changes of CD while utilizing radiation doses substantially lower than those associated with standard techniques.

Imaging of the small intestine in Crohn's disease: Joint position statement of the Indian Society of Gastroenterology and Indian Radiological and Imaging Association

The Indian Society of Gastroenterology (ISG) Task Force on Inflammatory Bowel Disease and the Indian Radiological and Imaging Association (IRIA) developed combined ISG-IRIA evidence-based best-practice guidelines for imaging of the small intestine in patients with suspected or known Crohn's disease. These 29 position statements, developed through a modified Delphi process, are intended to serve as reference for teaching, clinical practice, and research.

Tubercular Intestinal Strictures Show a Poor Response to Anti-Tuberculous Therapy

BACKGROUND

The literature on resolution of intestinal strictures in patients with intestinal tuberculosis (ITB) after anti-tuberculous therapy (ATT) is sparse and ambivalent. We aimed to assess the frequency of stricture resolution after ATT and its predictors.

METHODS

This ambispective cohort study included consecutive ITB patients with strictures who received ATT for ≥6 months and were on regular follow-up between January 2004 and December 2015. Resolution of stricture was assessed at the end of ATT by endoscopy/radiology.

RESULTS

Of 286 patients, 128 had strictures, and 106 were finally included (63 males, median age 35 years). The stricture location was distal ileum/ileocecal in 52 (49.1%), colon in 37 (34.9%), ileocolonic in 4 (3.8%), proximal small bowel in 10 (9.4%), and gastroduodenal in 4 (3.8%) patients. Although all patients demonstrated mucosal healing (indicating resolution of active infection), stricture resolution occurred only in 25/106 (23.6%) patients. Symptoms pertaining to stricture (pain abdomen/recurrent SAIO) were present in 104/106 (98%) patients, and after a median of 6 (6-9) months of ATT, these symptoms resolved only in half, 88% (22/25) in patients with stricture resolution and 38% (30/79) in patients with persistent strictures. Colonic strictures had the least resolution (5.4%) followed by proximal small intestinal (20%) and distal ileal/ileocecal (36.5%). Although not statistically significant, stricture resolution was less frequent in patients with multiple strictures, longer strictures (>3 cm), and strictures in which scope was not negotiable prior to ATT.

CONCLUSION

Only one-fourth of ITB patients with strictures show resolution of stricture following ATT. The resolution of strictures is dependent on disease location, and majority of them exhibit symptoms pertaining to stricture even after ATT.

Split-Bolus Injection Producing Simultaneous Late Arterial and Portal Venous Phases in CT Enterography: Preliminary Results

OBJECTIVE

The purpose of this article is to evaluate the image quality and added value of split-bolus contrast agent injection combining late arterial and portal venous phases compared with single-bolus contrast agent injection late arterial phase CT enterography.

MATERIALS AND METHODS

Consecutive patients who underwent CT enterography before and after implementation of a single-bolus CT enterography protocol were included. Attenuation and contrast-to-noise ratio (CNR) were assessed by ROI measurements of the bowel wall and arterial and venous structures. Subjective enhancement of the bowel wall (1, arterial; 2, mucosal; 3, transmural; 4, transmural with mucosal hyperenhancement) and bowel abnormalities were assessed by two independent readers. MR enterography examinations, endoscopy reports, and surgery reports within 30 days after CT enterography were used to produce a composite outcome.

RESULTS

Sixty-six patients were included in our study: 33 (mean [± SD] age, 46.0 ± 19.8 years) who underwent split-bolus CT enterography and 33 (mean age, 49.9 ± 19.0 years) who underwent single-bolus CT enterography. Bowel wall attenuation and CNR were higher for split-bolus CT enterography than for single-bolus CT enterography at 120 kVp (enhancement, 98.7 ± 23.1 HU vs 85.1 ± 23.3 HU; CNR, 6.4 ± 2.5 vs 4.4 ± 2.3; p < 0.01). Subjective ratings of bowel wall enhancement were higher with the split-bolus CT enterography than the single-bolus CT enterography (2.6 ± 0.8 vs 2.3 ± 0.6; p < 0.001). Split-bolus CT enterography led to a higher detection rate of mucosal hyperenhancement than did single-bolus CT enterography in patients with active inflammatory bowel disease (100.0% [7/7; 95% CI, 59.0-100.0%] vs 33.3% [2/6; 95% CI, 4.3-77.7%]; p = 0.02), whereas both protocols had a specificity of 100.0% (9/9).

CONCLUSION

Split-bolus CT enterography led to improved CNR (47%) compared with single-bolus CT enterography and significantly increased the detection rate of mucosal hyperenhancement in patients with active inflammatory bowel disease.

Using computed tomography enterography to evaluate patients with Crohn's disease: what impact does examiner experience have on the reproducibility of the method?

Objective

To assess the impact that examiner experience has on the reproducibility and accuracy of computed tomography (CT) enterography in the detection of radiological signs in patients with Crohn's disease.

Materials and Methods

This was a retrospective, cross-sectional observational study involving the analysis of CT enterography scans of 20 patients with Crohn's disease. The exams were analyzed independently by two radiologists in their last year of residence (duo I) and by two abdominal imaging specialists (duo II). The interobserver agreement of each pair of examiners in identifying the main radiological signs was calculated with the kappa test. The accuracy of the examiners with less experience was quantified by using the consensus among three experienced examiners as a reference.

Results

Duo I and duo II obtained a similar interobserver agreement, with a moderate to good correlation, for mural hyperenhancement, parietal thickening, mural stratification, fat densification, and comb sign (kappa: 0.45-0.64). The less experienced examiners showed an accuracy > 80% for all signs, except for lymph nodes and fistula, for which it ranged from 60% to 75%.

Conclusion

Less experienced examiners have a tendency to present a level of interobserver agreement similar to that of experienced examiners in evaluating Crohn's disease through CT enterography, as well as showing satisfactory accuracy in identifying most radiological signs of the disease.

Neoplastic Diseases of the Small Bowel

The incidence of small bowel tumors is increasing over time. Until recently, their diagnosis was delayed and it was often reached only at the time of surgery. New diagnostic tools, such as capsule endoscopy, device-assisted enteroscopy, and dedicated small bowel cross-sectional imaging techniques, have been introduced recently in clinical practice. The combination of these tools allows medical practitioners to detect small bowel tumors at an early stage and to reach a definite diagnosis before surgery, thus enabling minimally invasive treatments.

Magnetic Resonance Enterography in 300 Known Cases of Crohn's Disease: An Initial Report from a Referral Center in Iran

BACKGROUND

Magnetic resonance enterography (MRE) has become the modality of choice in assessment of patients with Crohn’s disease (CD). We aimed to present our experience on 300 patients with CD who underwent MRE during the first 30 months after setting up MRE for the first time in a referral center in Iran.

METHODS

Patients with a definite diagnosis of CD based on either ileocolonoscopy or histopathological studies were included in the final report and categorized into four phenotypes of inactive, active, stricturing, and penetrating disease.

RESULTS

This was a case series study on 300 patients with known CD out of 594 referred subjects. The most prevalent phenotype was inactive observed in 162 (54.0%) patients followed by stricturing in 44 (14.7%), active in 40 (13.3%), penetrating in 27(9%), and active on chronic in 27 (9%) cases. The number of referred patients increased from 51 cases in the first 6 months to 165 in the last 6 months.

CONCLUSION

This study presents the first report on the application of MRE in Iran as superb modality for management of CD. The growing number of referred patients indicates that MRE has been successful in addressing the most critical concerns of clinicians on determining the dominant disease phenotype.

Inter- and intraobserver agreement in computed tomography enterography in inflammatory bowel disease

AIM

To evaluate intra- and interobserver agreement in imaging features in inflammatory bowel disease and comparison with fecal calprotectin (FC) levels.

METHODS

Our institutional computed tomography enterography (CTE) database was retrospectively queried to identify patients who underwent CTE from January 2014 to June 2015. Patient inclusion criteria were confirmed inflammatory bowel disease (IBD) and FC collected < 4 mo after CTE without any change in clinical treatment or surgical treatment during this interval. The exclusion criterion was poor image quality. Two blinded abdominal radiologists, with 12 and 3 years of experience analyzed the CTE regarding localization (small bowel, colonic, both, or no disease detected); type of IBD (inflammatory, stenosing, fistulizing, > 1 pattern, or normal); and signs of active disease (present or absent). In 42 of 44 patients evaluated, routine CTE reports were made by one of the readers who re-evaluated the CTEs ≥ 6 mo later, to determine the intraobserver agreement. FC was considered a sign of disease activity when it was higher than 250 μg/g.

RESULTS

Forty-four patients with IBD (38 with Crohn’s disease and 6 with ulcerative colitis) were included. There was a moderate interobserver agreement regarding localization of IBD (κ = 0.540), type of disease (κ = 0.410) and the presence of active signs in CTE (κ = 0.419). There was almost perfect intraobserver agreement regarding localization, type and signs of active disease in IBD. The κ values were 0.902, 0.937 and 0.830, respectively. After a consensus between both radiologists regarding inflammatory activity in CTE, we found that 24 (85.7%) of 28 patients who were classified with active disease had elevated FC, and six (37.5%) of 16 patients without inflammatory activity in CTE had elevated FC (P = 0.003). The correlation between elevated FC and the presence of active disease in CTE was significant (κ = 0.495, P = 0.001).

CONCLUSION

We found almost perfect intraobserver and moderate interobserver agreement in the signs of active disease in CTE with concurrence of high FC levels.

Current tecniques and new perpectives research of magnetic resonance enterography in pediatric Crohn's disease

Crohn's disease affects more than 500000 individuals in the United States, and about 25% of cases are diagnosed during the pediatric period. Imaging of the bowel has undergone dramatic changes in the past two decades. The endoscopy with biopsy is generally considered the diagnostic reference standard, this combination can evaluates only the mucosa, not inflammation or fibrosis in the mucosa. Actually, the only modalities that can visualize submucosal tissues throughout the small bowel are the computed tomography (CT) enterography (CTE) with the magnetic resonance enterography (MRE). CT generally is highly utilized, but there is growing concern over ionizing radiation and cancer risk; it is a very important aspect to keep in consideration in pediatric patients. In contrast to CTE, MRE does not subject patients to ionizing radiation and can be used to detect detailed morphologic information and functional data of bowel disease, to monitor the effects of medical therapy more accurately, to detect residual active disease even in patients showing apparent clinical resolution and to guide treatment more accurately.

ACR Appropriateness Criteria Crohn Disease

Crohn disease is a chronic inflammatory disorder involving the gastrointestinal tract, characterized by episodic flares and times of remission. Underlying structural damage occurs progressively, with recurrent bouts of inflammation. The diagnosis and management of this disease process is dependent on several clinical, laboratory, imaging, endoscopic, and histologic factors. In recent years, with the maturation of CT enterography, and MR enterography, imaging has played an increasingly important role in relation to Crohn Disease. In addition to these specialized examination modalities, ultrasound and routine CT have potential uses. Fluoroscopy, radiography, and nuclear medicine may be less beneficial depending on the clinical scenario. The imaging modality best suited to evaluating this disease may change, depending on the target population, severity of presentation, and specific clinical situation. This document presents seven clinical scenarios (variants) in both the adult and pediatric populations and rates the appropriateness of the available imaging options. They are summarized in a consolidated table, and the underlying rationale and supporting literature are presented in the accompanying narrative. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Value of Computerized Tomography Enterography in Predicting Crohn's Disease Activity: Correlation with Crohn's Disease Activity Index and C-Reactive Protein

Background

The accurate evaluation of Crohn’s disease activity is important for the treatment of the disease and for monitoring the response. Computerized tomography (CT) enterography is a useful imaging modality that reflects enteric inflammation, as well as extramural complications.

Objectives

The aim of this study was to evaluate the correlation between CT enterographic (CTE) findings of active Crohn’s disease and the Crohn’s disease activity index (CDAI) and C-reactive protein (CRP).

Patients and Methods

Fifty CT enterographies of 39 patients with Crohn’s disease in the small bowel were used in our study. The CDAI was assessed through clinical and laboratory variables. Multiple CT parameters, including mural hyperenhancement, mural thickness, mural stratification, comb sign, and mesenteric fat attenuation, were evaluated with a four-point scale. The presence or absence of enhanced lymph nodes, fibrofatty proliferation, sinus or fistula, abscess, and stricture were also assessed. Two gastrointestinal radiologists independently reviewed all CT images, and inter-observer agreement was examined. Correlations between CT findings, CRP, and CDAI were assessed using Spearman’s rank correlation and logistic regression analysis. To assess the predictive accuracy of the model, a receiver-operating characteristic curve analysis for the sum of CT enterographic scores was used.

Results

Mural hyperenhancement, mural thickness, comb sign, mesenteric fat density, and fibrofatty proliferation were significantly correlated with CDAI and CRP (P < 0.05). The binary logistic regression model demonstrated that mesenteric fat density, mural stratification, and the presence of enhanced lymph nodes (P < 0.05) had an influence on CDAI severity. The area under the receiver operating characteristic curve (AUROC) of the CTE index for predicting disease activity was 0.85. Using a cut-off value of 8, the sensitivity and negative predictive values were 95% and 94%, respectively.

Conclusion

Most CTE findings correlated with CDAI and CRP in patients with active Crohn’s disease.

Considerations in Imaging Among Emergency Department Patients With Inflammatory Bowel Disease

Patients with inflammatory bowel disease who experience abdominal pain and gastrointestinal symptoms often seek care in the emergency department (ED). These patients commonly undergo abdominopelvic computed tomography (CT) as part of their evaluation, and the rate of imaging appears to be increasing without a corresponding increase in identification of clinically actionable findings or effect on disposition. Studies demonstrate that the yield of CT tends to be fairly high. Yet, because inflammatory bowel disease is often diagnosed at an early age, these patients are repeatedly imaged during their lifetime, a subset of whom accumulate high levels of ionizing radiation exposure, increasing their risk of cancer. This compounds an already increased risk of cancer in these patients because of inflammatory bowel disease alone. Lack of intimate knowledge of a patient's disease phenotype and disease progression contributes to uncertainty in distinguishing between an inflammatory exacerbation; a complication such as obstruction, abscess, perforation, fistula, or stricture; and a noninflammatory-bowel-disease-related condition. This uncertainty can lead to overuse of imaging with CT. Limited availability of and lack of awareness of alternate imaging modalities and strategies may prevent providers from pursuing strategies that avoid ionizing radiation. In this article, we review options for imaging inflammatory bowel disease patients in the ED and attempts undertaken to risk stratify these patients, and we discuss ways in which details of a patient's disease might guide imaging decisionmaking.

Identifying decreased peristalsis of abnormal small bowel segments in Crohn's disease using cine MR enterography: the frozen bowel sign

PURPOSE

The purpose of this study was to evaluate whether affected bowel in Crohn's disease patients can be identified by observing decreased peristalsis (frozen bowel sign) using cine balanced steady-state free precession (cine BSSFP) images.

MATERIALS AND METHODS

5 radiologists independently reviewed cine BSSFP sequences from randomized MR Enterography (MRE) exams for 30 normal and 30 Crohn's disease patients, graded overall small bowel peristalsis from slowest to fastest, and graded peristalsis for the most abnormal small bowel segment. Sensitivity and specificity of the frozen bowel sign for diagnosing Crohn's disease were calculated. T tests of the peristalsis difference between abnormal segments and overall small bowel were conducted.

RESULTS

For 5 readers, the sensitivity and specificity of cine BSSFP of the frozen bowel sign for diagnosing Crohn's disease ranged from 70% to 100% and 87% to 100%, respectively. There were significant differences in peristalsis between abnormal small bowel segments and the overall small bowel for Crohn's patients, but not in the overall small bowel between normal-MRE patients and Crohn's disease patients.

CONCLUSION

Abnormal Crohn's small bowel segments have significantly decreased peristalsis compared to normal small bowel, which can be identified using cine BSSFP sequences as the frozen bowel sign.

Low-dose CT for patients with clinically suspected acute appendicitis: optimal strength of sinogram affirmed iterative reconstruction for image quality and diagnostic performance

BACKGROUND

As there is increased concern over the radiation exposure particularly in adolescents and young adults, computed tomography (CT) dose reduction is needed in the diagnosis of acute appendicitis.

PURPOSE

To evaluate the optimal strength of sinogram affirmed iterative reconstruction (SAFIRE) to obtain the best image quality on a 30-mAs applied low-dose CT (LDCT 30mAs) and to compare the diagnostic performances of the LDCT 30mAs with different SAFIRE strengths with that of the 100-mAs applied LDCT (LDCT 100mAs) for the diagnosis of acute appendicitis.

MATERIAL AND METHODS

A total of 102 consecutive patients (47 men, 55 women; mean age, 41.2 years; range, 15-82 years) with right lower quadrant pain underwent abdominal-pelvic CT, consisting of arterial phase LDCT 100mAs and portal venous phase LDCT30mAs under a fixed 120 kV. LDCT 30mAs images were reconstructed separately with five strength levels (S1-S5). Two blinded radiologists recorded scores for the subjective image quality of the LDCT 30mAs dataset (S0-S5) and confidence scores for the diagnosis of acute appendicitis on each dataset and LDCT 100mAs. CT image noise was measured for each set.

RESULTS

The study population consisted of 58 patients with confirmed appendicitis and 44 without appendicitis. There was no significant difference in diagnostic performance between LDCT 100mAs and LDCT 30mAs with any strength for both readers (AUC for reader 1, LDCT 30mAs with S0-S5 = 0.97, LDCT 100mAs = 0.93, P = 0.0936; for reader 2, LDCT 30mAs with S0-S5 = 0.96, LDCT 100mAs = 0.97, P = 0.128). The measured noise decreased as the strength increased from S0 to S5 (mean, 20.8 > 17.7 > 15.6 > 13.5 > 11.5 > 9.5, P < 0.0001). However, overall subjective image quality on S3 was better than the other strengths for both readers (S0 < S1 < S2 < S3 > S4 > S5, P < 0.0001).

CONCLUSION

Although measured noise declined as SAFIRE strength increased, S3 seems optimal for the best subjective image quality on LDCT 30mAs. The diagnostic performance of LDCT 30mAs with any strength is comparable to that of LDCT 100mAs for the diagnosis of acute appendicitis.

High Spatiotemporal Resolution Dynamic Contrast-Enhanced MR Enterography in Crohn Disease Terminal Ileitis Using Continuous Golden-Angle Radial Sampling, Compressed Sensing, and Parallel Imaging

OBJECTIVE

The purpose of this article was to assess the feasibility of golden-angle radial acquisition with compress sensing reconstruction (Golden-angle RAdial Sparse Parallel [GRASP]) for acquiring high temporal resolution data for pharmacokinetic modeling while maintaining high image quality in patients with Crohn disease terminal ileitis.

MATERIALS AND METHODS

Fourteen patients with biopsy-proven Crohn terminal ileitis were scanned using both contrast-enhanced GRASP and Cartesian breath-hold (volume-interpolated breath-hold examination [VIBE]) acquisitions. GRASP data were reconstructed with 2.4-second temporal resolution and fitted to the generalized kinetic model using an individualized arterial input function to derive the volume transfer coefficient (K(trans)) and interstitial volume (v(e)). Reconstructions, including data from the entire GRASP acquisition and Cartesian VIBE acquisitions, were rated for image quality, artifact, and detection of typical Crohn ileitis features.

RESULTS

Inflamed loops of ileum had significantly higher K(trans) (3.36 ± 2.49 vs 0.86 ± 0.49 min(-1), p < 0.005) and v(e) (0.53 ± 0.15 vs 0.20 ± 0.11, p < 0.005) compared with normal bowel loops. There were no significant differences between GRASP and Cartesian VIBE for overall image quality (p = 0.180) or detection of Crohn ileitis features, although streak artifact was worse with the GRASP acquisition (p = 0.001).

CONCLUSION

High temporal resolution data for pharmacokinetic modeling and high spatial resolution data for morphologic image analysis can be achieved in the same acquisition using GRASP.

Plain magnetic resonance imaging as an alternative in evaluating inflammation and bowel damage in inflammatory bowel disease--a prospective comparison with conventional magnetic resonance follow-through

OBJECTIVE

To compare prospectively the diagnostic accuracy of magnetic resonance imaging (MRI) without use of contrast medium orally or intravenously (plain MRI) with magnetic resonance follow-through (MRFT) in patients with inflammatory bowel disease (IBD).

MATERIAL AND METHODS

Plain MRI was carried out in addition to MRFT, to which the patients were referred. All patients underwent both examinations on the same day. For the evaluation, the bowel was divided into nine segments. Two radiologists, blinded to clinical findings, evaluated bowel wall thickness, diffusion weighted imaging (DWI), and other inflammatory changes in each bowel segments. Further, hyperenhancement of the bowel was also evaluated in MRFT.

RESULTS

A total of 100 patients (40 males and 60 females; median age: 38.5; range: 19-90) were enrolled; 44 with Crohn's disease (CD), 25 with ulcerative colitis (UC), 24 with IBD unclassified (IBD-U), and 7 had other diagnosis. Sensitivity, specificity, and accuracy in CD ranged 50-86%, 93-94%, and 91-92% for wall thickening and 49-82%, 85-93%, and 84-89% for DWI, respectively. Sensitivity, specificity, and accuracy in UC range 0-40%, 87-100%, and 80-100% for wall thickening and 0-52%, 83-94% and 76-92% for DWI, respectively. The κ values for bowel wall thickening, DWI, and mural hyperenhancement were detected with fair agreement (κ = 0.26-0.39) at both MRI examinations, whereas only bowel wall thickening in MRFT were detected with moderate agreement (κ = 0.47) Conclusion. Plain MRI cannot currently replace MRFT in the workup of patients with IBD. Further research on plain MRI is needed to improve the protocol.