Assessment of appropriateness of indications for CT enterography in younger patients

Role of artificial intelligence in Crohn's disease intestinal strictures and fibrosis

Crohn's disease (CD) is a chronic inflammatory disorder of the gastrointestinal tract. Intestinal fibrosis or stricture is one of the most prevalent complications in CD with a high recurrence rate. Manual examination of intestinal fibrosis or stricture by physicians may be biased or inefficient. A rapid development of artificial intelligence (AI) technique in recent years facilitates the detection of existing or possible intestinal fibrosis and stricture in CD through various modalities, including endoscopy, imaging examination, and serological biomarkers. We reviewed the articles on AI application in diagnosing intestinal fibrosis and stricture in CD during the past decade and categorized them into three aspects based on the detection methods, and found that AI helps accurate and expedient identification and prediction of intestinal fibrosis and stenosis in CD.

Measuring appropriateness of diagnostic imaging: a scoping review

In radiology, the justification of diagnostic imaging is a key performance indicator. To date, specific recommendations on the measurement of appropriateness in diagnostic imaging are missing. To map the study literature concerning the definition, measures, methods and data used for analyses of appropriateness in research of diagnostic imaging. We conducted a scoping review in Medline, EMBASE, Scopus and the Cochrane Central Register of Controlled Trials. Two independent reviewers undertook screening and data extraction. After screening 6021 records, we included 50 studies. National guidelines (n = 22/50) or American College of Radiology Appropriateness Criteria (n = 23/50) were used to define and rate appropriateness. 22/50 studies did not provide methodological details about the appropriateness assessment. The included studies varied concerning modality, amount of reviewed examinations (88-13,941) and body regions. Computed tomography (27 studies, 27,168 examinations) was the most frequently analyzed modality, followed by magnetic resonance imaging (17 studies, 6559 examinations) and radiography (10 studies, 7095 examinations). Heterogeneous appropriateness rates throughout single studies (0-100%), modalities, and body regions (17-95%) were found. Research on pediatric and outpatient imaging was sparse. Multicentric, methodologically robust and indication-oriented studies would strengthen appropriateness research in diagnostic imaging and help to develop reliable key performance indicators.

Correlation between imaging findings on outpatient MR enterography (MRE) in adult patients with Crohn disease and progression to surgery within 5 years

PURPOSE

To retrospectively evaluate which key imaging features described by SAR-AGA on outpatient surveillance MRE correlate with progression to surgery in adults with CD.

METHODS

52 CD patients imaged with outpatient MRE from 10/2015 to 12/2016 and with available clinical information were included. Two abdominal radiologists reviewed the MRE for the presence of active inflammation, intramural edema, restricted diffusion, stricture, probable stricture, ulceration, sacculation, simple fistula, complex fistula, sinus tract, inflammatory mass, abscess, perienteric inflammation, engorged vasa recta, fibrofatty proliferation, and perianal disease. Bowel wall thickness, length of bowel involvement, and degree of upstream dilation in strictures were quantified. Subsequent bowel resection, prior bowel surgery, and available laboratory values were recorded. The association between progression to surgery and imaging features was evaluated using a logistic regression model adjusting for demographics, prior bowel surgery, medication usage, and body mass index.

RESULTS

19.2% (10/52) of patients progressed to surgery. Restricted diffusion, greater degree of upstream dilation from stricture, complex fistula, perienteric inflammation, and fibrofatty proliferation were significantly more common in patients progressing to surgery (all p < 0.05). κ for these significant findings ranged 0.568-0.885. Patients progressing to surgery had longer length bowel involvement (p = 0.03). Platelet count, ESR, and fecal calprotectin were significantly higher, and serum albumin was significantly lower in patients progressing to surgery. Prior bowel surgery, sex, age, and all other parameters were similar.

CONCLUSION

Radiologists should carefully describe bowel dilation upstream from strictures, penetrating and perienteric findings on outpatient MRE in CD patients, as these findings may herald progression to surgery.

Strictures in Crohn's Disease: From Pathophysiology to Treatment

Despite recent advances aimed to treat transmural inflammation in Crohn's disease (CD) patients, the progression to a structuring behavior still represents an issue for clinicians. As inflammation becomes chronic and severe, the attempt to repair damaged tissue can result in an excessive production of extracellular matrix components and deposition of connective tissue, thus favoring the formation of strictures. No specific and accurate clinical predictors or diagnostic tools for intestinal fibrosis exist, and to date, no genetic or serological marker is in routine clinical use. Therefore, intestinal fibrosis is usually diagnosed when it becomes clinically evident and strictures have already occurred. Anti-fibrotic agents such as tranilast, peroxisome proliferator-activated receptor gamma agonists, rho kinase inhibitors, and especially mesenchymal stem cell therapy have provided interesting results, but most of the evidence has been derived from studies performed in vitro. Therefore, current therapy of fibrotic strictures relies mainly on endoscopic and surgical procedures. Although its long-term outcomes may be debated, endoscopic balloon dilation appears to be the safest and most effective approach to treat appropriately selected strictures. The use of endoscopic stricturotomy is currently limited by the expertise needed to perform it and by the few data available in the literature. Some good results have been achieved by the positioning of self-expandable metal stents (SEMS). However, there is no concordance regarding the type of stent to use and for how long it should be left in place. The development of new specific SEMS may lead to better outcomes and to an increased use of this alternative in CD-related strictures.

Patients undergoing recurrent CT exams: assessment of patients with non-malignant diseases, reasons for imaging and imaging appropriateness

OBJECTIVE

To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness.

METHODS

From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1-3 (red) as "not usually appropriate," 4-6 (yellow) "may or may not be appropriate," and 7-9 (green) "usually appropriate." Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC).

RESULTS

9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease.

CONCLUSIONS

We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria.

KEY POINTS

We are faced with a situation wherein patients in age group 0-40 years and with non-malignant diagnosis require or are thought to require many CT exams over the course of a few years. More than half of CT exams were unrelated to follow-up of a primary chronic disease. Imaging guidelines and appropriateness use criteria are not available for many conditions. Wherever available, they are for initial work-up and diagnosis and there is a lack of guidance on serial CT imaging.

Evaluation of neutral oral contrast agents for assessment of the small bowel at abdominal staging CT

BACKGROUND

Although neutral oral contrast agents are widely in use, a consensus regarding a standardized protocol in abdominal staging CT does not exist.

PURPOSE

To test the null hypothesis that there is no quantitative or qualitative difference between water and mannitol for evaluation of the small bowel at abdominal staging CT.

MATERIAL AND METHODS

180 patients prospectively underwent abdominal staging CT with oral administration of either 1 liter mannitol solution (n = 88) or water (n = 92). Intestinal distension was measured in 6 different segments of the small intestine. In addition, two radiologists separately evaluated diagnostic image quality with regards to luminal distension (three-point scale) in each segment and the possibility to rule out a possible underlying pathology. Quantitative and qualitative results were compared (Mann-Whitney test).

RESULTS

Quantitatively, intestinal distension was comparable in all segments (p>0.05), except for the horizontal duodenum (p = 0.019). The mean luminal diameter over all intestinal segments was 19.0 mm (18.1-19.9 mm) for the water group and 18.4 mm (17.5-19.2 mm) for the mannitol group, respectively. Qualitatively, ratings were comparable for the first three segments, while distal segments were rated better using mannitol. Side effects were only observed using mannitol (n = 26; 29.5%).

CONCLUSIONS

Orally administered water and mannitol solution for evaluation of the small bowel at abdominal staging CT in clinical routine resulted in comparable results for the quantitative, but not for the qualitative analysis. Looking more differentiated at the overall performance, water has advantages in terms of patient comfort, side effects and costs, and can therefore be regarded as noninferior to mannitol in this specific patient group.

Differences in the imaging of Crohn's disease patients between North America and Europe: are we ready to bridge the divide?

The emphasis of treatment in Crohn's disease has evolved from a reactive model to "treat-to-target" approaches. Cross-sectional imaging has rapidly evolved in parallel, with a growing evidence base supporting its abilities for diagnosis, monitoring and prognostication. Whilst there are differences in emphasis between Europe and North America, particularly around the type of imaging modalities and patterns of multidisciplinary care, there is increasing convergence. This perspective piece provides an overview of the evolving role of cross-sectional imaging in Crohn's disease, discusses practice differences between North America and Europe and provides suggestions on areas for future collaboration and research priorities.

Risk factors for radiation exposure in newly diagnosed IBD patients

PURPOSE

Patients with inflammatory bowel disease (IBD) may be exposed to high doses of diagnostic radiation. The purpose of this study is to identify subsets of this population at risk for significant radiation exposure.

METHODS

This HIPAA compliant, IRB approved study consists of 336 patients (237 adult and 99 pediatric) within the Ocean State Crohn's & Colitis Area Registry (OSCCAR). All were newly diagnosed with IBD and prospectively enrolled between 1/2008 and 12/2012. Comprehensive chart review was performed.

RESULTS

207 (61.6%) patients were diagnosed with Crohn's disease (CD), 120 (35.7%) with ulcerative colitis (UC), and 9 (2.7%) with inflammatory bowel disease, type unspecified (IBDU). 192 (57.1%) patients were exposed to GI-specific radiation. Average GI-specific radiation dose for adult IBD patients was 14.1 mSV and was significantly greater among adult CD than adult UC patients (p = 0.01). Pediatric patients underwent fewer CT scans (p < 0.0001). Risk factors for increased radiation exposure include: GI surgery (p = 0.003), biologic therapy (p = 0.01), pain-predominant symptoms (as compared to diarrhea-predominant symptoms; p < 0.05), and isolated ileal disease (p = 0.02). Patients with stricturing or penetrating disease received higher radiation doses than patients with non-stricturing, non-penetrating disease (p < 0.0001).

CONCLUSIONS

A variety of risk factors are associated with increased exposure to ionizing radiation after diagnosis of IBD. Knowledge of these risk factors can help physicians prospectively identify patients at risk for elevated radiation exposure and consider low-dose or radiation-free imaging.

Particularities of Crohn's disease in pediatric patients: current status and perspectives regarding imaging modalities

A consensus on the best imaging modality evaluating inflammatory bowel disease in the pediatric population is lacking and it is often unclear which modality to choose in specific clinical circumstances. Children with inflammatory bowel disease are exposed to ionizing radiation from multiple imaging studies performed at initial diagnosis, throughout treatment and during the follow-up period. This paper discusses the value of different imaging techniques in pediatric patients with inflammatory bowel disease and gives a review of the literature. In addition, particular features of inflammatory bowel disease in children including the predilection of affected segments in the gastrointestinal tract are highlighted. Based on current literature knowledge, we encourage an integrative approach to the interpretation of clinical and imaging data for diagnosis and follow-up in daily clinical settings.

Observer performance for adaptive, image-based denoising and filtered back projection compared to scanner-based iterative reconstruction for lower dose CT enterography

PURPOSE

The purpose of this study was to compare observer performance for detection of intestinal inflammation for low-dose CT enterography (LD-CTE) using scanner-based iterative reconstruction (IR) vs. vendor-independent, adaptive image-based noise reduction (ANLM) or filtered back projection (FBP).

METHODS

Sixty-two LD-CTE exams were performed. LD-CTE images were reconstructed using IR, ANLM, and FBP. Three readers, blinded to image type, marked intestinal inflammation directly on patient images using a specialized workstation over three sessions, interpreting one image type/patient/session. Reference standard was created by a gastroenterologist and radiologist, who reviewed all available data including dismissal Gastroenterology records, and who marked all inflamed bowel segments on the same workstation. Reader and reference localizations were then compared. Non-inferiority was tested using Jackknife free-response ROC (JAFROC) figures of merit (FOM) for ANLM and FBP compared to IR. Patient-level analyses for the presence or absence of inflammation were also conducted.

RESULTS

There were 46 inflamed bowel segments in 24/62 patients (CTDIvol interquartile range 6.9-10.1 mGy). JAFROC FOM for ANLM and FBP were 0.84 (95% CI 0.75-0.92) and 0.84 (95% CI 0.75-0.92), and were statistically non-inferior to IR (FOM 0.84; 95% CI 0.76-0.93). Patient-level pooled confidence intervals for sensitivity widely overlapped, as did specificities. Image quality was rated as better with IR and AMLM compared to FBP (p < 0.0001), with no difference in reading times (p = 0.89).

CONCLUSIONS

Vendor-independent adaptive image-based noise reduction and FBP provided observer performance that was non-inferior to scanner-based IR methods. Adaptive image-based noise reduction maintained or improved upon image quality ratings compared to FBP when performing CTE at lower dose levels.

CT enterography: technical and interpretive pitfalls

CT enterography is a first-line test at many institutions to investigate potential small bowel disorders. While numerous articles have focused on the ability of CT enterography to diagnose and stage Crohn's disease, small bowel neoplasia, and malabsorptive or vascular disorders, this article reviews CT enterography limitations, technical and interpretive pitfalls, image review tactics, and complementary radiologic and endoscopic examinations to improve diagnostic accuracy. CT enterography limitations include its inability to demonstrate isolated mucosal abnormalities such as aphthous ulcers and its use of ionizing radiation. The most common technical pitfall of CT enterography is inadequate small bowel distention resulting from inadequate ingestion, gastric retention, or rapid small bowel transit of a large volume of neutral enteric contrast material. Additionally, segments of jejunum are frequently collapsed. Interpretive pitfalls commonly result from peristaltic contractions, transient intussusception and opaque intraluminal debris. Opaque debris is especially problematic during multiphasic CT enterography performed to identify potential small bowel sources of obscure gastrointestinal bleeding. False-negative examinations may result from inadequate radiation dose. Examinations complementary to CT enterography include small bowel follow through, enteroclysis, CT enteroclysis, MR enterography, MR enteroclysis, capsule endoscopy, and balloon-assisted endoscopy. Properly performed and accurately interpreted CT enterography contributes to the diagnosis and management of small bowel disease by itself and as a complement to other radiologic and optical small bowel imaging examinations.

Inflammatory bowel disease imaging: Current practice and future directions

The purpose of this paper is to evaluate the role of imaging in inflammatory bowel disease (IBD), including detection of extraluminal complications and extraintestinal manifestations of IBD, assessment of disease activity and treatment response, and discrimination of inflammatory from fibrotic strictures. IBD is a chronic idiopathic disease affecting the gastrointestinal tract that is comprised of two separate, but related intestinal disorders; Crohn’s disease and ulcerative colitis. The paper discusses, in detail the pros and cons of the different IBD imaging modalities that need to be considered in order to optimize the imaging and clinical evaluation of patients with IBD. Historically, IBD evaluation of the bowel has included imaging to assess the portions of the small bowel that are inaccessible to optical endoscopic visualization. This traditionally was performed using barium fluoroscopic techniques; however, cross-sectional imaging techniques (computed tomography and magnetic resonance imaging) are being increasingly utilized for IBD evaluation because they can simultaneously assess mural and extramural IBD manifestations. Recent advances in imaging technology, that continue to improve the ability of imaging to noninvasively follow disease activity and treatment response, are also discussed. This review article summarizes the current imaging approach in inflammatory bowel disease as well as the role of emerging imaging modalities.

Ultrasonographic imaging of inflammatory bowel disease in pediatric patients

Inflammatory bowel disease (IBD) is one of the most common chronic gastrointestinal diseases in pediatric patients. Choosing the optimal imaging modality for the assessment of gastrointestinal disease in pediatric patients can be challenging. The invasiveness and patient acceptance, the radiation exposure and the quality performance of the diagnostic test need to be considered. By reviewing the literature regarding imaging in inflammatory bowel disease the value of ultrasound in the clinical management of pediatric patients is highlighted. Transabdominal ultrasound is a useful, noninvasive method for the initial diagnosis of IBD in children; it also provides guidance for therapeutic decisions and helps to characterize and predict the course of the disease in individual patients. Ultrasound techniques including color Doppler imaging and contrast-enhanced ultrasound are promising imaging tools to determine disease activity and complications. Comparative studies between different imaging methods are needed.

Magnetic resonance enterography: state of the art

Crohn's disease is a chronic inflammatory bowel disease of the gastrointestinal tract manifested by frequent periods of relapses and remissions of symptoms. The small bowel is most frequently affected. Progression of transmural inflammation can lead to stricturing or penetrating complications. At the time of diagnosis, approximately 10% of patients have disease beyond the reach of the colonoscope. Imaging can aid in clinical evaluation by depicting small bowel involvement and extraenteric disease. Magnetic resonance enterography (MRE) has emerged as a valuable tool and is being used with increasing frequency for the diagnosis and management of Crohn's disease. This article will discuss the current state of the art in MRE. In addition to reviewing the literature reporting its utility, we will present case examples illustrating how MRE best depicts the various findings of Crohn's disease within 4 imaging categories of disease: active inflammatory, fibrostenotic, fistulizing/perforating, and reparative or regenerative. We will present additional important clinical considerations in routine use of MRE, including implications for monitoring disease activity and response to treatment, cost-effectiveness, and appropriate use in the context of the American College of Radiology Appropriateness Criteria.

Abdominal and pelvic CT: is positive enteric contrast still necessary? Results of a retrospective observational study

PURPOSE

Evaluation of diagnostic accuracy of abdominal CT depending on the type of enteric contrast agent.

METHODS AND MATERIALS

Multislice CTs of 2,008 patients with different types of oral preparation (positive with barium, n = 576; neutral with water, n = 716; and no enteric contrast, n = 716) were retrospectively evaluated by two radiologists including delineation of intestinal segments and influence on diagnosis and diagnostic reliability exerted by the enteric contrast, using a three-point scale. Furthermore, diagnostic reliability of the delineation of selected enteric pathologies was noted. CT data were assigned into groups: oncology, inflammation, vascular, pathology, trauma and gastrointestinal pathology.

RESULTS

Delineation of the bowel was clearly practicable across all segments irrespective of the type of enteric contrast, though a slight impairment was observed without enteric contrast. Although delineation of intestinal pathologies was mostly classified "clearly delimitable" more difficulties occurred without oral contrast (neutral/positive/no contrast, 0.8 %/3.8 %/6.5 %). Compared to examinations without enteric contrast, there was a significant improvement in diagnosis that was even increased regarding the reader's diagnostic reliability. Positive opacification impaired detection of mucosal enhancement or intestinal bleeding.

CONCLUSION

Water can replace positive enteric contrast agents in abdominal CTs. However, selected clinical questions require individual enteric contrast preparations. Pathology detection is noticeably impaired without any enteric contrast.

Radiation exposure from diagnostic imaging studies among patients with inflammatory bowel disease in a safety-net health-care system

BACKGROUND/AIMS

Radiographic imaging studies are important in the management of patients with inflammatory bowel disease (IBD), but are associated with radiation exposure. IBD patients in a safety-net health-care system may be at risk of high exposure to radiation. Our purpose was to identify associations of high-dose radiation exposure among an ethnically diverse cohort of IBD patients in a safety-net health-care system.

METHODS

A study was performed on patients with IBD receiving care from the Harris County Hospital District. Radiation exposure was calculated using total number of imaging studies performed between from 2000 and 2010 and estimates of radiation dose per study. Associations of high-dose radiation exposure, defined as a cumulative effective dose (CED) >50 mSv, were identified by using univariate and multivariate logistic regression.

RESULTS

The study cohort of 278 patients with IBD was ethnically diverse, with 30 % Caucasian, 44 % African-American, and 26 % Hispanic. The median CED was 10.40 mSv (SD 20.02). Annualized radiation doses were 3.45 mSv/year among patients with Crohn's disease (CD) and 1.27 mSv/year among patients with ulcerative colitis, p < 0.02. Approximately 13 % of IBD patients received a CED >50 mSv. There were no differences in radiation exposure based on age, gender, or race/ethnicity.

CONCLUSIONS

A small proportion of IBD patients in a safety-net health-care system received high doses of diagnostic radiation exposure. Use of diagnostic imaging studies that limit radiation exposure should be encouraged.

Imaging of pediatric patients with inflammatory bowel disease

OBJECTIVE

The goal of this review is to examine the current imaging literature and develop basic imaging guidelines for evaluation of children with inflammatory bowel disease (IBD). The three following typical clinical scenarios in the imaging evaluation of IBD are considered: patient with an initial diagnosis of suspected IBD, the goals being to determine disease extent and severity and to differentiate Crohn disease from ulcerative colitis; patient with known IBD presenting with new acute symptoms (fever, peritonitis, leukocytosis) requiring urgent evaluation; and patient with known IBD presenting with nonacute symptomatic recurrence (abdominal pain, diarrhea), the goals being to assess the efficacy of the current treatment and to evaluate the possible need for additional medical or surgical intervention.

CONCLUSION

Imaging of pediatric patients with IBD must balance considerations of diagnostic accuracy against concerns about patient exposure to ionizing radiation and tolerance of the imaging technique. The imaging modality chosen depends on the clinical presentation and expected pathologic finding.

Small intestine contrast ultrasonography vs computed tomography enteroclysis for assessing ileal Crohn's disease

AIM: To compare computed tomography enteroclysis (CTE) vs small intestine contrast ultrasonography (SICUS) for assessing small bowel lesions in Crohn's disease (CD), when using surgical pathology as gold standard.

METHODS: From January 2007 to July 2008, 15 eligible patients undergoing elective resection of the distal ileum and coecum (or right colon) were prospectively enrolled. All patients were under follow-up. The study population included 6 males and 9 females, with a median age of 44 years (range: 18-80 years). Inclusion criteria: (1) certain diagnosis of small bowel requiring elective ileo-colonic resection; (2) age between 18-80 years; (3) elective surgery in our Surgical Unit; and (4) written informed consent. SICUS and CTE were performed ≤ 3 mo before surgery, followed by surgical pathology. The following small bowel lesions were blindly reported by one sonologist, radiologist, surgeon and histolopathologist: disease site, extent, strictures, abscesses, fistulae, small bowel dilation. Comparison between findings at SICUS, CTE, surgical specimens and histological examination was made by assessing the specificity, sensitivity and accuracy of each technique, when using surgical findings as gold standard.

RESULTS: Among the 15 patients enrolled, CTE was not feasible in 2 patients, due to urgent surgery in one patients and to low compliance in the second patient, refusing to perform CTE due to the discomfort related to the naso-jejunal tube. The analysis for comparing CTE vs SICUS findings was therefore performed in 13 out of the 15 CD patients enrolled. Differently from CTE, SICUS was feasible in all the 15 patients enrolled. No complications were observed when using SICUS or CTE. Surgical pathology findings in the tested population included: small bowel stricture in 13 patients, small bowel dilation above ileal stricture in 10 patients, abdominal abscesses in 2 patients, enteric fistulae in 5 patients, lymphnodes enlargement (> 1 cm) in 7 patients and mesenteric enlargement in 9 patients. In order to compare findings by using SICUS, CTE, histology and surgery, characteristics of the small bowel lesions observed in CD each patient were blindly reported in the same form by one gastroenterologist-sonologist, radiologist, surgeon and anatomopathologist. At surgery, lesions related to CD were detected in the distal ileum in all 13 patients, also visualized by both SICUS and CTE in all 13 patients. Ileal lesions > 10 cm length were detected at surgery in all the 13 CD patients, confirmed by SICUS and CTE in the same 12 out of the 13 patients. When using surgical findings as a gold standard, SICUS and CTE showed the exactly same sensitivity, specificity and accuracy for detecting the presence of small bowel fistulae (accuracy 77% for both) and abscesses (accuracy 85% for both). In the tested CD population, SICUS and CTE were also quite comparable in terms of accuracy for detecting the presence of small bowel strictures (92% vs 100%), small bowel fistulae (77% for both) and small bowel dilation (85% vs 82%).

CONCLUSION: In our study population, CTE and the non-invasive and radiation-free SICUS showed a comparable high accuracy for assessing small bowel lesions in CD.

18F-FDG positron emission tomography: potential utility in the assessment of Crohn's disease

Computed Tomography Enterography (CTE) and Magnetic Resonance Enterography (MRE) are currently the dominant imaging tests used in the assessment of patients with Crohn's disease. More recently, the possibility of utilizing F-18 fluorodeoxyglucose (18F-FDG) Positron Emission Tomography (PET) or PET/CT has been explored in several preliminary studies. 18F-FDG PET appears to enable reliable detection of moderate to severe inflammation in bowel segments involved by Crohn's disease. Perhaps more importantly, 18F-FDG PET has the potential to provide a noninvasive, quantitative measure of inflammation that dynamically reflects changes in Crohn's disease activity. If 18F-FDG PET proves useful in monitoring responses to medical therapy within a few days of therapy initiation, an important new role for imaging in the management of patients with Crohn's disease could emerge.

Cost-effectiveness of imaging strategies to reduce radiation-induced cancer risk in Crohn's disease

BACKGROUND

The aim was to examine the cost-effectiveness of magnetic resonance enterography (MRE) compared with computed tomography enterography (CTE) for routine imaging of small bowel Crohn's disease (CD) patients to reduce patients' life-time radiation-induced cancer risk.

METHODS

We developed a Markov model to compare the lifetime costs, benefits (measured in quality-adjusted life-years [QALYs] of survival and cancers averted) and cost-effectiveness of using MRE rather than CTE for routine disease monitoring in hypothetical cohorts of 100,000 20-year-old patients with CD. We assumed each CT radiation exposure conferred an incremental annual risk of developing cancer using the linear, no-threshold model.

RESULTS

In the base case of 16 mSv per CTE, we estimated that radiation from CTE resulted in 1,206 to 20,146 additional cancers depending on the frequency of patient monitoring. Compared to using CTE only, using MRE until age 30 and CTE thereafter resulted in incremental cost-effectiveness ratios (ICERs) between $37,538 and $41,031 per life-year (LY) gained and between $52,969 and $57,772 per quality-adjusted life-year (QALY) gained. Using MRE until age 50 resulted in ICERs between $58,022 and $62,648 per LY gained and between $84,250 and $90,982 per QALY gained. In a threshold analysis, any use of MRE had an ICER of greater than $100,000 per QALY gained when CT radiation doses are less than 6.0 mSv per CTE exam.

CONCLUSIONS

MRE is likely cost-effective compared to CTE in patients younger than age 50. Low-dose CTE may be an alternative cost-effective choice in the future.

Cancer risks associated with external radiation from diagnostic imaging procedures

The 600% increase in medical radiation exposure to the US population since 1980 has provided immense benefit, but increased potential future cancer risks to patients. Most of the increase is from diagnostic radiologic procedures. The objectives of this review are to summarize epidemiologic data on cancer risks associated with diagnostic procedures, describe how exposures from recent diagnostic procedures relate to radiation levels linked with cancer occurrence, and propose a framework of strategies to reduce radiation from diagnostic imaging in patients. We briefly review radiation dose definitions, mechanisms of radiation carcinogenesis, key epidemiologic studies of medical and other radiation sources and cancer risks, and dose trends from diagnostic procedures. We describe cancer risks from experimental studies, future projected risks from current imaging procedures, and the potential for higher risks in genetically susceptible populations. To reduce future projected cancers from diagnostic procedures, we advocate the widespread use of evidence-based appropriateness criteria for decisions about imaging procedures; oversight of equipment to deliver reliably the minimum radiation required to attain clinical objectives; development of electronic lifetime records of imaging procedures for patients and their physicians; and commitment by medical training programs, professional societies, and radiation protection organizations to educate all stakeholders in reducing radiation from diagnostic procedures.

Magnetic resonance enterography: safe and effective imaging for stricturing Crohn's disease

BACKGROUND

Symptomatic Crohn's disease (CD) patients often undergo diagnostic imaging studies for evaluation of disease activity or complications including bowel strictures and obstruction. Magnetic resonance enterography (MRE) provides information regarding disease activity, chronicity, and stricture formation without using ionizing radiation.

AIM

Examine the use of MRE among CD patients presenting with symptoms suggesting obstruction in a tertiary care practice setting.

METHODS

We performed a retrospective study of all CD patients undergoing MRE at a tertiary IBD referral center over a 3-year study period including a subgroup analysis of patients presenting obstructive symptoms. Positive and negative findings from MRE were correlated with medical and surgical decision outcomes over the subsequent 90-day period.

RESULTS

In the study, 119 CD patients underwent 133 MRE scans, including 40 scans on individuals presenting with obstructive symptoms. Positive findings of CD including active inflammation, stricturing, and penetrating disease were more frequent in MREs ordered to evaluate obstructive symptoms (87.5%) compared other indications (58.1%, p = 0.001). In patients presenting with obstructive symptoms, MRE findings assisted in directing a change of clinical management towards escalation of medical therapy in 55% and surgery in 32.5%. Review of surgical resection specimens corroborated MRE findings of disease activity and fibrosis in 92% of cases going to surgery.

CONCLUSIONS

In practice-based use at a tertiary IBD referral center, MRE provided an effective, radiation-free alternative to computed tomography by providing valuable diagnostic information for evaluating and directing care in Crohn's disease, particularly for patients presenting with obstructive symptoms.

Guidelines for the diagnosis and management of distal intestinal obstruction syndrome in cystic fibrosis patients

Complete or incomplete intestinal obstruction by viscid faecal material in the terminal ileum and proximal colon - distal intestinal obstruction syndrome (DIOS) - is a common complication in cystic fibrosis. Estimates of prevalence range from 5 to 12 episodes per 1000 patients per year in children, with higher rates reported in adults. DIOS is mainly seen in patients with pancreatic insufficiency, positive history of meconium ileus and previous episodes of DIOS. DIOS is being described with increasing frequency following organ transplantation. Diagnosis is based on suggestive symptoms with a right lower quadrant mass confirmed on X-ray. The main differential is chronic constipation. Treatment consists of rehydration combined with stool softening laxatives or gut lavage with balanced electrolyte solutions. Rapid fluid shifts have been described following osmotic agents. Avoiding dehydration and optimizing pancreatic enzyme dosage may reduce the chance of further episodes. Prophylactic laxative therapy is widely used, but is not evidence-based.

New concepts in intestinal imaging for inflammatory bowel diseases

In the last decade, multiple imaging technologies have been developed that improve visualization of the mucosal, mural, and perienteric inflammation associated with inflammatory bowel diseases. Whereas these technologies have traditionally been used to detect and stage suspected enteric inflammation, we review new, emerging roles in detecting clinically occult inflammation (in asymptomatic patients) and inflammatory complications, predicting response prior to therapy, assessing response after therapy, and enteric healing. We compare the relative performance of these technologies in detecting inflammation, focusing on their advantages and disadvantages and how they might complement each other. We also discuss their potential benefits for patients and clinical trials, reviewing technologic developments and areas of research that could provide important insights into the pathophysiology of inflammatory bowel diseases-related enteric inflammation.

Crohn's disease: CT enterography manifestations before and after treatment

PURPOSE

The purpose of this study was to determine whether CT enterography (CTE) changes of Crohn's disease (CD) after treatment correlated with clinical remission.

MATERIALS AND METHODS

We retrospectively studied 50 known CD patients (male: 35; female: 15) with clinical remission in a period of 3 years (2005-2008). CD was diagnosed by clinical, enteroscopic and pathologic manifestations. Clinical remission was identified by experienced gastroenterologists using the combing criteria of clinical, endoscopy and laboratory tests. First CTE and endoscopy exams were performed during their first hospitalization in our hospital meanwhile CD diagnosis was made during that time. Repeated CTE and endoscopy exams were done after treatment. CTE findings were determined by two experienced radiologists with double-blind approach. Each patient was analyzed for the CTE parameters including bowel wall attenuation, bowel wall thickening (>3mm), bowel wall thickening types (type A: multilayered mural stratification; type B: two layers with strong mucosal enhancement and prominent low-density submucosa; type C: two layers without strong mucosal enhancement; type D: homogeneous enhancement) comb sign, luminal stenosis (mild: luminal diameter 2-3 cm; moderate: luminal diameter 1-2 cm; severe: luminal diameter<1cm) and the presence of extraenteric complications (such as fistulas and abscess). All the quantitative parameters were measured three times by each review.

RESULTS

After treatment, bowel wall thickening was attenuated in 88% of CD patients. Thickness of bowel wall was decreased from 8.8 ± 2.8mm to 6.4 ± 1.9 mm (P<0.001). CT value of bowel wall in portal stage was also declined from 90.0 ± 15.4 (HU) to 73.4 ± 14.2 (HU (P<0.001). The percentage of patients with type A or B bowel wall thickening was decreased from 78.7% to 35.4%, while those with type C or D thickening was increased from 21.2% to 64.6% (P<0.001). The percentage of patients with comb sign was decreased from 88% to 60% (P=0.001). The percentage of patients with moderate or severe luminal stenosis was reduced from 74% to 32% (P<0.001). The ROC (receiver operating characteristic) analysis showed bowel wall attenuation (A(z)=0.89) and bowel wall thickness (A(z)=0.81) were the two best parameters to predict disease activity, and combining of these two values was better than using them solely (κ=0.71, P<0.001). The bowel wall attenuation (OR=9.56, P<0.001) and bowel wall thickness (OR=3.32, P=0.001) were significantly correlated with the disease activity in the following logistic regression analysis.

CONCLUSION

Therapeutic effect of CD and disease activity can be properly evaluated by CTE.

Low-dose 18F-FDG PET/CT enterography: improving on CT enterography assessment of patients with Crohn disease

The purpose of this study was to evaluate the diagnostic efficacy of low-dose, combined (18)F-FDG PET/CT enterography (PET/CTE), compared with CT enterography (CTE) alone, in the assessment of patients with Crohn disease.

METHODS

Thirteen patients with Crohn disease were prospectively enrolled in this pilot study and underwent abdominal-pelvic (18)F-FDG PET/CTE using neutral oral and intravenous contrast medium. The effective dose from PET/CTE was 17.7 mSv for the first 4 patients and 8.31 mSv for the last 9 patients. Six patients underwent surgical resection of the bowel, and 7 patients underwent colonoscopy with biopsies within 27 d (mean, 12 d) of PET/CTE. PET/CTE and CTE images were each visually assessed for Crohn disease involvement in 54 bowel segments with pathology correlation. Extraintestinal findings were recorded. A CTE severity score, maximum standardized uptake value (SUVmax), SUVmax ratio, simplified endoscopic score, and clinical parameters were correlated with pathology inflammation grade, on a per-patient basis and on a per-bowel-segment basis, using Spearman correlation.

RESULTS

In 3 (23.1%) of 13 patients, (18)F-FDG uptake using PET/CTE revealed active inflammation in a bowel segment not evident using CTE (n = 2) or revealed an enterocolic fistula missed with CTE (n = 1). Visual interpretation of both PET/CTE and CTE images detected the presence of disease in all bowel segments with more than mild inflammation (sensitivity, 100%; specificity, 89.7%; positive predictive value, 78.9%; and negative predictive value, 100%). Correlation to inflammation grade per patient was the strongest for the SUVmax ratio (0.735, P = 0.004) and SUVmax (0.67, P = 0.013), as compared with the CTE score (0.62, P = 0.024). Correlation with inflammation per bowel segment was higher for the CTE score (0.79, P < 0.0001) than the SUVmax ratio (0.62, P < 0.0001) or SUVmax (0.48, P < 0.0001). SUVmax correlated strongly with serum C-reactive protein (0.82, P = 0.023), but CTE score did not.

CONCLUSION

Low-dose (18)F-FDG PET/CTE, compared with CTE, may improve the detection and grading of active inflammation in patients with Crohn disease. PET/CTE also may reveal clinically significant findings, such as enterocolic fistula, not evident on PET or CTE alone.