Asymptomatic neonatal herpes simplex virus infection in mice leads to long-term cognitive impairment

Neonatal herpes simplex virus (nHSV) is a devastating infection impacting approximately 14,000 newborns globally each year. Infection is associated with high neurologic morbidity and mortality, making early intervention and treatment critical. Clinical outcomes of symptomatic nHSV infections are well-studied, but little is known about the frequency of, or outcomes following, sub-clinical or asymptomatic nHSV. Given the ubiquitous nature of HSV infection and frequency of asymptomatic shedding in adults, subclinical infections are underreported, yet could contribute to long-term neurological damage. To assess potential neurological morbidity associated with subclinical nHSV infection, we developed a low-dose (100 PFU) HSV infection protocol in neonatal C57BL/6 mice. At this dose, HSV DNA was detected in the brain by PCR but was not associated with acute clinical symptoms. However, months after initial inoculation with 100 PFU of HSV, we observed impaired mouse performance on a range of cognitive and memory performance tasks. Memory impairment was induced by infection with either HSV-1 or HSV-2 wild-type viruses, but not by a viral mutant lacking the autophagy-modulating Beclin-binding domain of the neurovirulence gene γ34.5. Retroviral expression of wild type γ34.5 gene led to behavioral pathology in mice, suggesting that γ34.5 expression may be sufficient to cause cognitive impairment. Maternal immunization and HSV-specific antibody treatment prevented offspring from developing neurological sequelae following nHSV-1 infection. Altogether, these results support the idea that subclinical neonatal infections may lead to cognitive decline in adulthood, with possible profound implications for research on human neurodegenerative disorders such as Alzheimer's Disease.

Survey of rectal cancer MRI technique and reporting tumour descriptors in the UK: a multi-centre British Society of Gastrointestinal and Abdominal Radiology (BSGAR) audit

AIM

To evaluate variation in magnetic resonance imaging (MRI) technique and reporting of rectal cancer staging examinations across the UK.

MATERIALS AND METHODS

A retrospective, multi-centre audit was undertaken of imaging protocols and information documented within consecutive MRI rectal cancer reports between March 2020 and August 2021, which were compared against American and European guidelines. Inclusion criteria included histologically proven rectal adenocarcinoma and baseline staging MRI rectum only.

RESULTS

Fully anonymised data from 924 MRI reports by 78 radiologists at 24 centres were evaluated. Thirty-two per cent of radiologists used template reporting, but these reports offered superior documentation of 13 out of 18 key tumour features compared to free-text reports including T-stage, relation to peritoneal reflection and mesorectal fascia (MRF), nodal status, and presence of extramural venous invasion (EMVI; p<0.027 in each). There was no significant differences in the remaining five features. Across all tumour locations, the tumour relationship to the MRF, the presence of EMVI, and the presence of tumour deposits were reported in 79.5%, 85.6%, and 44% of cases, respectively, and tumour, nodal, and distant metastatic stage documented in 94.4%, 97.7%, and 78.3%. In low rectal tumours, the relationship to the anal sphincter complex was reported in only 54.6%.

CONCLUSION

Considerable variation exists in rectal cancer MRI acquisition and reporting in this sample of UK centres. Inclusion of key radiological features in reports must be improved for risk stratification and treatment decisions. Template reporting is superior to free-text reporting. Routine adoption of standardised radiology practices should now be considered to improve standards to facilitate personalised precision treatment for patients to improve outcomes.

METRIC-EF: magnetic resonance enterography to predict disabling disease in newly diagnosed Crohn's disease-protocol for a multicentre, non-randomised, single-arm, prospective study

INTRODUCTION

Crohn's disease (CD) is characterised by discontinuous, relapsing enteric inflammation. Instituting advanced therapies at an early stage to suppress inflammation aims to prevent future complications such as stricturing or penetrating disease, and subsequent surgical resection. Therapeutics are effective but associated with certain side-effects and relatively expensive. There is therefore an urgent need for robust methods to predict which newly diagnosed patients will develop disabling disease, to identify patients who are most likely to benefit from early, advanced therapies. We aim to determine if magnetic resonance enterography (MRE) features at diagnosis improve prediction of disabling CD within 5 years of diagnosis.

METHODS AND ANALYSIS

We describe the protocol for a multicentre, non-randomised, single-arm, prospective study of adult patients with newly diagnosed CD. We will use patients already recruited to the METRIC study and extend their clinical follow-up, as well as a separate group of newly diagnosed patients who were not part of the METRIC trial (MRE within 3 months of diagnosis), to ensure an adequate sample size. Follow-up will extend for at least 4 years. The primary outcome is to evaluate the comparative predictive ability of prognostic models incorporating MRE severity scores (Magnetic resonance Enterography Global Score (MEGS), simplified MAgnetic Resonance Index of Activity (sMaRIA) and Lémann Index) versus models using standard characteristics alone to predict disabling CD (modified Beaugerie definition) within 5 years of new diagnosis.

ETHICS AND DISSEMINATION

This study protocol achieved National Health Service Research Ethics Committee (NHS REC), London-Hampstead Research Ethics Committee approval (IRAS 217422). Our findings will be disseminated via conference presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ISRCTN76899103.

Imaging features for the prediction of clinical endpoints in chronic liver disease: a scoping review protocol

INTRODUCTION

Chronic liver disease is a growing cause of morbidity and mortality in the UK. Acute presentation with advanced disease is common and prioritisation of resources to those at highest risk at earlier disease stages is essential to improving patient outcomes. Existing prognostic tools are of limited accuracy and to date no imaging-based tools are used in clinical practice, despite multiple anatomical imaging features that worsen with disease severity.In this paper, we outline our scoping review protocol that aims to provide an overview of existing prognostic factors and models that link anatomical imaging features with clinical endpoints in chronic liver disease. This will provide a summary of the number, type and methods used by existing imaging feature-based prognostic studies and indicate if there are sufficient studies to justify future systematic reviews.

METHODS AND ANALYSIS

The protocol was developed in accordance with existing scoping review guidelines. Searches of MEDLINE and Embase will be conducted using titles, abstracts and Medical Subject Headings restricted to publications after 1980 to ensure imaging method relevance on OvidSP. Initial screening will be undertaken by two independent reviewers. Full-text data extraction will be undertaken by three pretrained reviewers who have participated in a group data extraction session to ensure reviewer consensus and reduce inter-rater variability. Where needed, data extraction queries will be resolved by reviewer team discussion. Reporting of results will be based on grouping of related factors and their cumulative frequencies. Prognostic anatomical imaging features and clinical endpoints will be reported using descriptive statistics to summarise the number of studies, study characteristics and the statistical methods used.

ETHICS AND DISSEMINATION

Ethical approval is not required as this study is based on previously published work. Findings will be disseminated by peer-reviewed publication and/or conference presentations.

A122 WATER EXCHANGE FACILITATES HIGH CECAL INTUBATION RATE FOLLOWING INCOMPLETE COLONOSCOPY

Background

Incomplete colonoscopy is a complex problem that negatively affects the success of colon cancer screening programs. Failure to intubate the cecum is associated with a significant risk of missed colorectal cancer and increases costs through missed diagnoses and salvage investigations. Water exchange (WE) colonoscopy is associated with a high rate of patient comfort and cecal intubation (CI) and may be of value in preventing and following up on incomplete colonoscopy.

Aims

To estimate effectiveness of WE colonoscopy as initial salvage of incomplete colonoscopy.

Methods

All patients referred to the Kelowna Gastroenterology group for incomplete colonoscopy between Jan 2010 to Dec 2019 were included. Demographic, clinical, procedural, and pathological information were collected via retrospective chart review. Patients underwent WE colonoscopy by a single endoscopist. The outcomes evaluated were CI rate, sedation requirements, and adenoma detection.

Results

116 patients met study criteria and underwent WE colonoscopy after a previously failed or incomplete colonoscopy for technical reasons. The mean age was 66 years (range 21–89). 83 (72%) patients were female. 53 (46%) patients had previous abdominal surgery, and 42 (36%) had previous pelvic surgery. 65 (56%) patients had previous bowel disease. 81 (70%) patients had previously incomplete conventional air insufflation (AI) colonoscopy, 9 (8%) patients had previously incomplete WE colonoscopy, and 5 (4%) patients underwent unsuccessful combination of WE and AI colonoscopy. 17 (15%) patients had previously incomplete flexible sigmoidoscopy, and 4 (3%) patients had previously incomplete water immersion colonoscopy. The most common cause of unsuccessful CI was redundant colon (n=39, 34%) followed by strictures/angulations (n=16, 14%). 105 (91%) patients underwent repeat WE colonoscopy only, while 7 (6%) patients had combination WE and AI colonoscopy and 4 (3%) patients had concurrent gastroscopy. CI was successful in 114 (98%) patients and unsuccessful in 2 (2%) patients. 87 (75%) study patients received conscious sedation, 16 (14%) opted for no sedation, and 7 (6%) attempted no sedation then switched to conscious sedation. 5 patients (4%) required general anesthesia. CI was achieved in all 16 unsedated patients. 236 polyps were identified in 79 (68%) patients, 2 (1%) of which were malignant.

Conclusions

There is no standardized approach to incomplete colonoscopy. In this cohort of patients with previous failed attempt at colonoscopy, WE as a primary technique was associated with a high success rate with minimal need for general anesthesia and a high rate of polyp detection. A significant rate of colon cancer was identified, similar to that seen in general screening populations.

Funding Agencies

None

Opportunities in cancer imaging: a review of oesophageal, gastric and colorectal malignancies

The incidence of gastrointestinal (GI) malignancy is increasing worldwide. In particular, there is a concerning rise in incidence of GI cancer in younger adults. Direct endoscopic visualisation of luminal tumour sites requires invasive procedures, which are associated with certain risks, but remain necessary because of limitations in current imaging techniques and the continuing need to obtain tissue for diagnosis and genetic analysis; however, management of GI cancer is increasingly reliant on non-invasive, radiological imaging to diagnose, stage, and treat these malignancies. Oesophageal, gastric, and colorectal malignancies require specialist investigation and treatment due to the complex nature of the anatomy, biology, and subsequent treatment strategies. As cancer imaging techniques develop, many opportunities to improve tumour detection, diagnostic accuracy and treatment monitoring present themselves. This review article aims to report current imaging practice, advances in various radiological modalities in relation to GI luminal tumour sites and describes opportunities for GI radiologists to improve patient outcomes.

Liver perfusion MRI in a rodent model of cirrhosis: Agreement with bulk-flow phase-contrast MRI and noninvasive evaluation of inflammation in chronic liver disease using flow-sensitive alternating inversion recovery arterial spin labelling and tissue T1

Noninvasive measurements of liver perfusion and fibrosis in cirrhotic small animals can help develop treatments for haemodynamic complications of liver disease. Here, we measure liver perfusion in cirrhotic rodents using flow-sensitive alternating inversion recovery arterial spin labelling (FAIR ASL), evaluating agreement with previously validated caval subtraction phase-contrast magnetic resonance imaging (PCMRI) total liver blood flow (TLBF). Baseline differences in cirrhotic rodents and the haemodynamic effects of acute inflammation were investigated using FAIR ASL and tissue T1. Sprague-Dawley rats (nine bile duct ligated [BDL] and ten sham surgery controls) underwent baseline hepatic FAIR ASL with T1 measurement and caval subtraction PCMRI (with two-dimensional infra-/supra-hepatic inferior vena caval studies), induction of inflammation with intravenous lipopolysaccharide (LPS) and repeat liver FAIR ASL with T1 measurement after ~90 minutes. The mean difference between FAIR ASL hepatic perfusion and caval subtraction PCMRI TLBF was -51 ± 30 ml/min/100 g (Bland-Altman 95% limits-of-agreement ±258 ml/min/100 g). The FAIR ASL coefficient of variation was smaller than for caval subtraction PCMRI (29.3% vs 50.1%; P = .03). At baseline, FAIR ASL liver perfusion was lower in BDL rats (199 ± 32 ml/min/100 g vs sham 316 ± 24 ml/min/100 g; P = .01) but liver T1 was higher (BDL 1533 ± 50 vs sham 1256 ± 18 ms; P = .0004). Post-LPS FAIR ASL liver perfusion response differences were observed between sham/BDL rats (P = .02), approaching significance in sham (+78 ± 33 ml/min/100 g; P = .06) but not BDL rats (-49 ± 40 ml/min/100 g; P = .47). Post-LPS differences in liver tissue T1 were nonsignificant (P = .35). FAIR ASL hepatic perfusion and caval subtraction PCMRI TLBF agreement was modest, with significant baseline FAIR ASL liver perfusion and tissue T1 differences in rodents with advanced cirrhosis compared with controls. Following inflammatory stress, differences in hepatic perfusion response were detected between cirrhotic/control animals, but liver T1 was unaffected. Findings underline the potential of FAIR ASL in the assessment of vasoactive treatments for patients with chronic liver disease and inflammation.

Assessment of body composition and association with clinical outcomes in patients with lung and colorectal cancer

Objectives:

To assess body composition in patients with non-small cell lung cancer (NSCLC) and colorectal cancer using whole-body MRI and relate this to clinical outcomes.

Methods:

53 patients with NSCLC (28 males, 25 females; mean age 66.9) and 74 patients with colorectal cancer (42 males, 32 females; mean age 62.9) underwent staging whole-body MRI scans, which were post-processed to derive fat mass (FM), fat free mass (FFM) and skeletal muscle (SM) indices and SM fat fraction (FF). These were compared between the two cancer cohorts using two-sided t-tests and the chi-squared test. Measurements of body composition were correlated with outcomes including length of hospital stay, metastatic status and mortality.

Results:

Patients with NSCLC had significantly lower FFM (p = 0.0071) and SM (p = 0.0084) indices. Mean SM FF was greater in patients with NSCLC (p = 0.0124) and was associated with longer hospital stay (p = 0.035). There was no significant relationship between FM, FFM and SM indices and length of hospital stay, metastatic status or mortality.

Conclusions:

Patients with NSCLC had lower FFM and SM indices than patients with colorectal cancer and greater SMFF, indicating lower SM mass with fatty infiltration. These findings reflect differences in the phenotype of the two groups and suggest patients with lung cancer are more likely to require additional nutritional support.

Advances in knowledge:

Body composition differs between NSCLC and colorectal cancer. Patients with NSCLC have both a reduced SM mass and greater SM FF suggesting that they are more nutritionally deplete than patients with colorectal cancer.

A273 ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY IN A TERTIARY CANADIAN HOSPITAL: OPTIMIZING TISSUE SAMPLING TECHNIQUES

Background

Pancreatic and biliary cancer can be difficult to definitively diagnose, and tissue diagnosis defines clinical management in both early and late disease. The majority of patients with pancreaticobiliary malignancy present with late disease and only 30% have resectable tumours, contributing to poor prognosis and outcome. Endoscopic retrograde cholangiopancreatography (ERCP) is a mainstay for diagnosing and treating conditions of the bile and pancreatic duct.

Aims

This study aimed to provide data on the diagnostic performance of ERCP utilizing conventional methods for tissue acquisition particularly in the setting of an indeterminate stricture. In particular, this was a quality assurance review to determine our centre’s baseline performance as a reference so new methods of tissue acquisition such as SpyglassTM can be benchmarked against.

Methods

In a tertiary care hospital, 3723 ERCP procedures were performed between 2013 and 2017. Demographic and clinical information was retrospectively collected. Demographic and clinical information was collected. Three ERCP techniques of tissue sampling were analyzed: brushing alone (BiA), biopsy alone (BrA), and brushing and biopsy dual-modality approach (BrBi). The diagnostic performances (sensitivity, specificity, and accuracy) were calculated with data from post-sampling clinical reports, surgical pathological reports, and diagnostic imaging reports.

Results

222 patients (285 ERCP procedure) met the study criteria and received fluoroscopy-guided ERCP sampling with cytology brushing and/or tissue biopsies. 36 (13%) patients had BiA, 85 (29%) patients had BrA, and 164 (58%) patients had BrBi. The sensitivities, specificities, and accuracies of the three sampling techniques respectively were: 56%, 93%, and 85% for BiA; 73%, 96%, and 83% for BrA; and 79%, 94%, and 86% for BrBi.

Conclusions

Our retrospective analysis of fluoroscopic-guided tissue acquisition shows accuracy as high as current published data on direct visualization cholangiosopy guided techniques. A prospective study looking not only at clinical yield but a cost analysis should be put in place prior to a commitment to purchase new equipment such as the SpyglassTM.

Funding Agencies

None

The evolution of magnetic resonance enterography in the assessment of motility disorders in children

Gastrointestinal symptoms including constipation, diarrhoea, pain and bloating represent some of the most common clinical problems for patients. These symptoms can often be managed with cheap, widely available medication or will spontaneously resolve. However, for many patients, chronic GI symptoms persist and frequently come to dominate their lives. At one end of the spectrum there is Inflammatory Bowel Disease (IBD) with a clearly defined but expensive treatment pathway. Contrasting with this is Irritable Bowel Syndrome (IBS), likely a collection of pathologies, has a poorly standardised pathway with unsatisfactory clinical outcomes. Managing GI symptoms in adult populations is a challenge. The clinical burden of gastrointestinal disease is also prevalent in paediatric populations and perhaps even harder to treat. In this review we explore some of the recent advances in magnetic resonance imaging (MRI) to study the gastrointestinal tract. Complex in both its anatomical structure and its physiology we are likely missing key physiological markers of disease through relying on symptomatic descriptors of gut function. Using MRI we might be able to characterise previously opaque processes, such as non-propulsive contractility, that could lead to changes in how we understand even common symptoms like constipation. This review explores recent advances in the field in adult populations and examines how this safe, objective and increasingly available modality might be applied to paediatric populations.

Relationship between MRI quantified small bowel motility and abdominal symptoms in Crohn's disease patients-a validation study

OBJECTIVE

Previous single-centre MRI data suggests an inverse correlation between normal small bowel motility variance and abdominal symptoms in Crohn's disease (CD) patients. The current work prospectively assesses this observation in a larger, two-centre study.

METHODS

MR enterography datasets were analysed from 82 patients (38 male, aged 16-68), who completed a contemporaneous Harvey-Bradshaw index (HBI) questionnaire. Dynamic "cine motility" breath-hold balanced steady-state free precession sequences were acquired through the whole small bowel (SB) volume. Regions of interest (ROIs) were manually applied to encompass all morphologically normal SB (i.e. excluding Crohn's affected bowel) and a validated registration technique used to produce motility maps. Mean and variance motility metrics were correlated with HBI and symptom components (well-being, pain and diarrhoea) using Spearman's correlation statistics.

RESULTS

Overall, motility variance was non-significantly negatively correlated with the total HBI score, (r = -0.17, p = 0.12), but for subjects with a HBI score over 10, the negative correlation was significant (r = -0.633, p = 0.027). Motility variance was negatively correlated with diarrhoea (r = -0.29, p < 0.01). No significant correlation was found between mean motility and HBI (r = -0.02, p = 0.84).

CONCLUSION

An inverse association between morphologically normal small bowel motility variance and patient symptoms has been prospectively confirmed in patients with HBI scores above 10. This association is particularly apparent for the symptom of diarrhoea. Advances in knowledge: This study builds on preliminary work by confirming in a large, well-controlled prospective multicentre study a relationship between normal bowel motility variance and patient reported symptoms which may have implications for drug development and clinical management.

MRI assessment of the postprandial gastrointestinal motility and peptide response in healthy humans

BACKGROUND

Feeding triggers inter-related gastrointestinal (GI) motor, peptide and appetite responses. These are rarely studied together due to methodological limitations. Recent MRI advances allow pan-intestinal, non-invasive assessment of motility in the undisturbed gut. This study aimed to develop a methodology to assess pan-intestinal motility and transit in a single session using MRI and compare imaging findings to GI peptide responses to a test meal and symptoms in a healthy volunteer cohort.

METHODS

Fifteen healthy volunteers (29.3±2.7 years and BMI 20.1±1.2 kg m^-2 ) underwent baseline and postprandial MRI scans, symptom questionnaires, and blood sampling (for subsequent GI peptide analysis, Glucagon-like peptide-1 [GLP-1], Polypeptide YY [PYY], Cholecystokinin [CCK]) at intervals for 270 minutes following a 400 g soup meal (204 kcal, Heinz, UK). Gastric volume, gall bladder volume, small bowel water content, small bowel motility, and whole gut transit were measured from the MRI scans.

KEY RESULTS

(mean±SEM) Small bowel motility index increased from fasting 39±3 arbitrary units (a.u.) to a maximum of 87±7 a.u. immediately after feeding. PYY increased from fasting 98±10 pg mL^-1 to 149±14 pg mL^-1 at 30 minutes and GLP-1 from fasting 15±3 μg mL^-1 to 22±4 μg mL^-1 . CCK increased from fasting 0.40±0.06 pmol mL^-1 to 0.94±0.1 pmol mL^-1 . Gastric volumes declined with a T_1/2 of 46±5 minute and the gallbladder contracted from a fasting volume of 19±2 mL^-1 to 12±2 mL^-1 . Small bowel water content increased from 39±2 mL^-1 to 51±2 mL^-1 postprandial. Fullness VAS score increased from 9±5 mm to 41±6 mm at 30 minutes postprandial.

CONCLUSIONS AND INFERENCES

The test meal challenge was effective in inducing a change in MRI motility end-points which will improve understanding of the pathophysiological postprandial GI response.

The development of a magnetic resonance imaging index for fistulising Crohn's disease

BACKGROUND

Magnetic resonance imaging (MRI) is the gold standard for assessment of perianal fistulising Crohn's disease (CD). The Van Assche index is the most commonly used MRI fistula index.

AIMS

To assess the reliability of the Van Assche index, and to modify the instrument to improve reliability and create a novel index for fistulising CD.

METHODS

A consensus process developed scoring conventions for existing Van Assche index component items and new items. Four experienced radiologists evaluated 50 MRI images in random order on three occasions. Reliability was assessed by estimates of intraclass correlation coefficients (ICCs). Common sources of disagreement were identified and recommendations made to minimise disagreement. A mixed effects model used a 100 mm visual anologue scale (VAS) for global severity as outcome and component items as predictors to create a modified Van Assche index.

RESULTS

Intraclass correlation coefficients (95% confidence intervals) for intra-rater reliability of the original and modified Van Assche indices and the VAS were 0.86 (0.81-0.90), 0.90 (0.86-0.93) and 0.86 (0.82-0.89). Corresponding ICCs for inter-rater reliability were 0.66 (0.52-0.76), 0.67 (0.55-0.75) and 0.58 (0.47-0.66). Sources of disagreement included number, location, and extension of fistula tracts, and rectal wall involvement. A modified Van Assche index (range 0-24) was created that included seven component items.

CONCLUSIONS

Although "almost perfect" intra-rater reliability was observed for the assessment of MRI images for fistulising CD using the Van Assche index, inter-rater reliability was considerably lower. Our modification of this index should result in a more optimal instrument.

A magnetic resonance imaging study of gastric motor function in patients with dyspepsia associated with Ehlers-Danlos Syndrome-Hypermobility Type: A feasibility study

BACKGROUND

The clinical use of Magnetic Resonance Imaging (MRI) for investigating gastric motor function in dyspepsia is limited, largely due to protocol complexity, cost and limited availability. In this study, we explore the feasibility of a sub 60-minute protocol using a water challenge to assess gastric emptying, motility and accommodation in a cohort of Ehlers-Danlos Syndrome-Hypermobility type (EDS-HT) patients presenting with dyspepsia.

METHODS

Nine EDS-HT patients (mean age 33, range: 26-50 all female) with a history of dyspepsia were recruited together with nine-matched controls. Subjects fasted for 6 hours prior to MRI. A baseline anatomical and motility scan was performed after which the subjects ingested 300 mL water. The anatomical and motility scans were then repeated every 10 minutes to a total of 60 minutes. Gastric emptying time, motility, and accommodation were calculated based on the observations of two observers for each EDS-HT subject and compared to their matched control using paired statistics.

KEY RESULTS

Median motility increase following the water challenge was lower in EDS-HT subjects (11%, range: 0%-22%) compared to controls (22%, range: 13%-56%), P=.03. Median gastric emptying time was non-significantly decreased in EDS-HT subjects (12.5 minutes, range: 6-27) compared to controls (20 minutes, range: 7-30), P=.15. Accommodation was non-significantly reduced in EDS-HT subjects (56% increase, range: 32%-78%) compared to healthy controls (67% increase, range: 52%-78%), P=.19.

CONCLUSIONS & INFERENCES

This study demonstrates the feasibility of a water challenge MRI protocol to evaluate gastric physiology in the clinical setting. Motility differences between EDS-HT and controls are worthy of further investigation.

Safety and acceptability of an organic light-emitting diode sleep mask as a potential therapy for retinal disease

PurposeThe purpose of the study was to study the effect of an organic light-emitting diode sleep mask on daytime alertness, wellbeing, and retinal structure/function in healthy volunteers and in diabetic macular oedema (DMO).Patients and methodsHealthy volunteers in two groups, 18-30 yrs (A), 50-70 yrs (B) and people with DMO (C) wore masks (504 nm wavelength; 80 cd/m² luminance; ≤8 h) nightly for 3 months followed by a 1-month recovery period. Changes from baseline were measured for (means): psychomotor vigilance task (PVT) (number of lapses (NL), response time (RT)), sleep, depression, psychological wellbeing (PW), visual acuity, contrast sensitivity, colour, electrophysiology, microperimetry, and retinal thickness on OCT.ResultsOf 60 participants, 16 (27%) withdrew, 8 (13%) before month 1, due to sleep disturbances and mask intolerance. About 36/55 (65%) who continued beyond month 1 reported ≥1 adverse event. At month 3 mean PVT worsened in Group A (RT (7.65%, P<0.001), NL (43.3%, P=0.005)) and mean PW worsened in all groups (A 28.0%, P=0.01, B 21.2%, P=0.03, C 12.8%, P<0.05). No other clinically significant safety signal was detected. Cysts reduced/resolved in the OCT subfield of maximal pathology in 67% Group C eyes. Thinning was greater at 3 and 4 months for greater baseline thickness (central subfield P<0.001, maximal P<0.05).ConclusionSleep masks showed no major safety signal apart from a small impairment of daytime alertness and a moderate effect on wellbeing. Masks were acceptable apart from in some healthy participants. Preliminary data suggest a beneficial effect on retinal thickness in DMO. This novel therapeutic approach is ready for large clinical trials.

Comparative quantitative assessment of global small bowel motility using magnetic resonance imaging in chronic intestinal pseudo-obstruction and healthy controls

BACKGROUND

Chronic intestinal pseudo-obstruction (CIPO) is characterized by dilatation of the bowel lumen and abnormal motility. In this study, we aimed to quantify small bowel dysmotility in CIPO using a validated pan-intestinal motility assessment technique based on motion capture magnetic resonance imaging (MRI) compared to normal controls. In addition, we explored if motility responses of CIPO patients to neostigmine challenge differed from healthy volunteers.

METHODS

Twenty healthy volunteers (mean age 28, range 22-48) and 11 CIPO patients (mean age 47, range 19-90) underwent MRI enterography to capture global small bowel motility. Eleven controls and seven CIPO patients further underwent a randomized placebo-controlled crossover study of either intravenous neostigmine (0.5 mg) or saline with motility MRI repeated at a mean of 3 weeks. Motility was quantified in regions of interest placed to encompass the whole small bowel volume using a validated, postprocessing technique to give a global motility index in arbitrary units (AU). Baseline and stimulated motility was compared using Wilcoxon rank-sum paired T-tests.

KEY RESULTS

Baseline global small bowel motility was significantly lower in CIPO patients compared to controls (mean 0.25 AU vs 0.35 AU, p < 0.001). Motility in both groups increased significantly after neostigmine (0.06 AU increase, p = 0.016 in CIPO and 0.06 AU increase, p = 0.002 in controls). Three patients with scleroderma had a reduced response to neostigmine.

CONCLUSIONS & INFERENCES

Global small bowel motility in CIPO patients is significantly lower than controls and response to the pro-kinetic agent neostigmine may differ according to disease phenotype. Software-quantified bowel motility using cine MRI has potential as a future tool to investigate enteric dysmotility.

Colon wall motility: comparison of novel quantitative semi-automatic measurements using cine MRI

BACKGROUND

Recently, cine magnetic resonance imaging (MRI) has shown promise for visualizing movement of the colonic wall, although assessment of data has been subjective and observer dependent. This study aimed to develop an objective and semi-automatic imaging metric of ascending colonic wall movement, using image registration techniques.

METHODS

Cine balanced turbo field echo MRI images of ascending colonic motility were acquired over 2 min from 23 healthy volunteers (HVs) at baseline and following two different macrogol stimulus drinks (11 HVs drank 1 L and 12 HVs drank 2 L). Motility metrics derived from large scale geometric and small scale pixel movement parameters following image registration were developed using the post ingestion data and compared to observer grading of wall motion. Inter and intra-observer variability in the highest correlating metric was assessed using Bland-Altman analysis calculated from two separate observations on a subset of data.

KEY RESULTS

All the metrics tested showed significant correlation with the observer rating scores. Line analysis (LA) produced the highest correlation coefficient of 0.74 (95% CI: 0.55-0.86), p < 0.001 (Spearman Rho). Bland-Altman analysis of the inter- and intra-observer variability for the LA metric, showed almost zero bias and small limits of agreement between observations (-0.039 to 0.052 intra-observer and -0.051 to 0.054 inter-observer, range of measurement 0-0.353).

CONCLUSIONS & INFERENCES

The LA index of colonic motility derived from cine MRI registered data provides a quick, accurate and non-invasive method to detect wall motion within the ascending colon following a colonic stimulus in the form of a macrogol drink.

Monitoring Crohn's disease during anti-TNF-α therapy: validation of the magnetic resonance enterography global score (MEGS) against a combined clinical reference standard

OBJECTIVES

To assess the ability of magnetic resonance enterography global score (MEGS) to characterise Crohn's disease (CD) response to anti-TNF-α therapy.

METHODS

Thirty-six CD patients (median age 26 years, 20 males) commencing anti-TNF-α therapy with concomitant baseline MRI enterography (MRE) were identified retrospectively. Patients' clinical course was followed and correlated with subsequent MREs. Scan order was randomised and MEGS (a global activity score) was applied by two blinded radiologists. A physician's global assessment of the disease activity (remission, mild, moderate or severe) at the time of MRE was assigned. The cohort was divided into clinical responders and non-responders and MEGS compared according to activity status and treatment response. Interobserver agreement was assessed.

RESULTS

Median MEGS decreased significantly between baseline and first follow-up in responders (28 versus 6, P < 0.001) but was unchanged in non-responders (26 versus 18, P = 0.28). The median MEGS was significantly lower in clinical remission (9) than in moderate (14) or severe (29) activity (P < 0.001). MEGS correlated significantly with clinical activity (r = 0.53; P < 0.001). Interobserver Bland-Altman limits of agreement (BA LoA) were -19.7 to 18.5.

CONCLUSIONS

MEGS decreases significantly in clinical responders to anti-TNF-α therapy but not in non-responders, demonstrates good interobserver agreement and moderate correlation with clinical disease activity.

KEY POINTS

• MRI scores of Crohn's activity are used increasingly in clinical practice and therapeutic trials. • Such scores have been advocated as biomarkers of therapeutic response. • MEGS reflects clinical response to anti-TNF-α therapy and the clinical classification of disease activity. • MEGS demonstrates good interobserver agreement.

Magnetic resonance imaging-quantified small bowel motility is a sensitive marker of response to medical therapy in Crohn's disease

BACKGROUND

Magnetic resonance enterography (MRE) can measure small bowel motility, reduction in which reflects inflammatory burden in Crohn's Disease (CD). However, it is unknown if motility improves with successful treatment.

AIM

To determine if changes in segmental small bowel motility reflect response to anti-TNFα therapy after induction and longer term.

METHODS

A total of 46 patients (median 29 years, 19 females) underwent MRE before anti-TNFα treatment; 35 identified retrospectively underwent repeat MRE after median 55 weeks of treatment and 11 recruited prospectively after median 12 weeks. Therapeutic response was defined by physician global assessment (retrospective group) or a ≥3 point drop in the Harvey-Bradshaw Index (prospective group), C-reactive protein (CRP) and the MaRIA score. Two independent radiologists measured motility using an MRE image-registration algorithm. We compared motility changes in responders and nonresponders using the Mann-Whitney test.

RESULTS

Anti-TNFα responders had significantly greater improvements in motility (median = 73.4% increase from baseline) than nonresponders (median = 25% reduction, P < 0.001). Improved MRI-measured motility was 93.1% sensitive (95%CI: 78.0-98.1%) and 76.5% specific (95% CI: 52.7-90.4%) for anti-TNFα response. Patients with CRP normalisation (<5 mg/L) had significantly greater improvements in motility (median = 73.4% increase) than those with persistently elevated CRP (median = 5.1%, P = 0.035). Individuals with post-treatment MaRIA scores of <11 had greater motility improvements (median = 94.7% increase) than those with post-treatment MaRIA score >11 (median 15.2% increase, P = 0.017).

CONCLUSIONS

Improved MRI-measured small bowel motility accurately detects response to anti-TNFα therapy for Crohn's disease, even as early as 12 weeks. Motility MRI may permit early identification of nonresponse to anti-TNFα agents, allowing personalised treatment.

Effect of faecal occult blood positivity on detection rates and positive predictive value of CT colonography when screening for colorectal neoplasia

AIM

To determine the detection rates and positive predictive value (PPV) of computed tomography (CT) colonography (CTC) according to the magnitude of faecal occult blood test (FOBt) positivity.

MATERIALS AND METHODS

Anonymised data from individuals undergoing CTC after a positive FOBt in the English Bowel Cancer Screening Programme were analysed. The detection of colorectal cancer (CRC), advanced neoplasia, and ≥ 6 mm polyps were stratified by the number of positive FOBt windows. The PPV was calculated by reference to subsequent endoscopy results. The influence of the FOBt result on detection rates was estimated with multilevel logistic regression. PPV, CRC stage, and location were compared across groups according to FOBt positivity.

RESULTS

Four thousand, six hundred and one individuals were included (mean = 66.7 years, 54.2% men). Detection rates of CRC and advanced neoplasia increased with greater numbers of positive FOBt windows (odds ratio [OR] for CRC = 1.41; 95% confidence interval [CI]: 1.31-1.52; OR for advanced neoplasia = 1.17; 95%CI: 1.12-1.23; both p < 0.0001). The PPV was significantly greater at higher FOBt levels (p = 0.020). The number of positive FOBt windows had no significant effect on stage (p = 0.30) or location (p = 0.20) of confirmed CRC.

CONCLUSIONS

The magnitude of FOBt positivity influences the PPV and detection rates when screening for colorectal neoplasia. CTC may be particularly useful for FOBt patients with few positive test windows.

Dual registration of abdominal motion for motility assessment in free-breathing data sets acquired using dynamic MRI

At present, registration-based quantification of bowel motility from dynamic MRI is limited to breath-hold studies. Here we validate a dual-registration technique robust to respiratory motion for the assessment of small bowel and colonic motility. Small bowel datasets were acquired in breath-hold and free-breathing in 20 healthy individuals. A pre-processing step using an iterative registration of the low rank component of the data was applied to remove respiratory motion from the free breathing data. Motility was then quantified with an existing optic-flow (OF) based registration technique to form a dual-stage approach, termed Dual Registration of Abdominal Motion (DRAM). The benefit of respiratory motion correction was assessed by (1) assessing the fidelity of automatically propagated segmental regions of interest (ROIs) in the small bowel and colon and (2) comparing parametric motility maps to a breath-hold ground truth. DRAM demonstrated an improved ability to propagate ROIs through free-breathing small bowel and colonic motility data, with median error decreased by 90% and 55%, respectively. Comparison between global parametric maps showed high concordance between breath-hold data and free-breathing DRAM. Quantification of segmental and global motility in dynamic MR data is more accurate and robust to respiration when using the DRAM approach.

The challenge of segmental small bowel motility quantitation using MR enterography

OBJECTIVE

Analysis of "cine" MRI using segmental regions of interest (ROIs) has become increasingly popular for investigating bowel motility; however, variation in motility in healthy subjects both within and between scans remains poorly described.

METHODS

20 healthy individuals (mean age, 28 years; 14, males) underwent MR enterography to acquire dynamic motility scans in both breath hold (BH) and free breathing (FB) on 2 occasions. Motility data were quantitatively assessed by placing four ROIs per subject in different small bowel segments and applying two measures: (1) contractions per minute (CPM) and (2) Jacobian standard deviation (SD) motility score. Within-scan (between segment) variation was assessed using intraclass correlation (ICC), and repeatability was assessed using Bland-Altman limits of agreement (BA LoA).

RESULTS

Within-scan segmental variation: BH CPM and Jacobian SD metrics between the four segments demonstrated ICC R = 0.06, p = 0.100 and R = 0.20, p = 0.027 and in FB, the CPM and Jacobian SD metrics demonstrated ICC R = -0.26, p = 0.050 and R = 0.19, p = 0.030. Repeatability: BH CPM for matched segments ranged between 0 and 14 contractions with BA LoA of ±8.36 and Jacobian SD ranged between 0.09 and 0.51 with LoA of ±0.33. In FB data, CPM ranged between 0 and 10 contractions with BA LoA of ±7.25 and Jacobian SD ranged between 0.16 and 0.63 with LoA = ±0.28.

CONCLUSION

The MRI-quantified small bowel motility in normal subjects demonstrates wide intersegmental variation and relatively poor repeatability over time.

ADVANCES IN KNOWLEDGE

This article presents baseline values for healthy individuals of within- and between-scan motility that are essential for understanding how this process changes in disease.

Abdominal computed tomography, colonography and radiation exposure: what the surgeon needs to know

AIM

Abdominal computed tomography (CT) improves the accuracy of clinical diagnosis and facilitates patient management. Radiation exposure must be considered by requesting clinicians and is especially relevant owing to the increasing use of CT colonography for diagnosis and screening of colorectal disorders. This review describes the radiation dose of abdominopelvic CT and colonography and attempts to quantify the risk for the clinician.

METHOD

Articles were searched in the PubMed and Medline databases using combinations of the MeSH terms 'radiation', 'abdominal computed tomography' and 'colonography'. Electronic English language abstracts were read by two reviewers and the full article was retrieved if relevant to the review.

RESULTS

Abdominopelvic CT and CT colonography convey significant radiation dose to the patient but also have considerable diagnostic potential. In the right clinical context, the radiation risk should not be overestimated. Techniques to reduce the dose should be used. Repeated imaging in certain patients is a concern and should be monitored.

CONCLUSION

Radiation risk can be quantified and presented simply in a manner that both patients and doctors can comprehend and evaluate. This approach will diminish misconceptions and allow a rational choice of diagnostic test.

Towards a framework for analysis of eye-tracking studies in the three dimensional environment: a study of visual search by experienced readers of endoluminal CT colonography

OBJECTIVE

Eye tracking in three dimensions is novel, but established descriptors derived from two-dimensional (2D) studies are not transferable. We aimed to develop metrics suitable for statistical comparison of eye-tracking data obtained from readers of three-dimensional (3D) "virtual" medical imaging, using CT colonography (CTC) as a typical example.

METHODS

Ten experienced radiologists were eye tracked while observing eight 3D endoluminal CTC videos. Subsequently, we developed metrics that described their visual search patterns based on concepts derived from 2D gaze studies. Statistical methods were developed to allow analysis of the metrics.

RESULTS

Eye tracking was possible for all readers. Visual dwell on the moving region of interest (ROI) was defined as pursuit of the moving object across multiple frames. Using this concept of pursuit, five categories of metrics were defined that allowed characterization of reader gaze behaviour. These were time to first pursuit, identification and assessment time, pursuit duration, ROI size and pursuit frequency. Additional subcategories allowed us to further characterize visual search between readers in the test population.

CONCLUSION

We propose metrics for the characterization of visual search of 3D moving medical images. These metrics can be used to compare readers' visual search patterns and provide a reproducible framework for the analysis of gaze tracking in the 3D environment.

ADVANCES IN KNOWLEDGE

This article describes a novel set of metrics that can be used to describe gaze behaviour when eye tracking readers during interpretation of 3D medical images. These metrics build on those established for 2D eye tracking and are applicable to increasingly common 3D medical image displays.

Small bowel strictures in Crohn's disease: a quantitative investigation of intestinal motility using MR enterography

BACKGROUND

Intestinal stricturing and aberrant small bowel motility are common complications in patients with Crohn's disease (CD) leading to significant morbidity. A retrospective study was performed quantifying small bowel motility within and upstream of strictures in CD patients using magnetic resonance enterography (MRE).

METHODS

A total of 91 subjects with stricturing CD (mean age 36 range 18-88) and undergoing MRE with dynamic motility imaging were identified. Of this cohort, 84 subjects were scanned at 1.5 T field strength with the remainder at 3 T. Linear regions of interest (ROI) were placed at the stricture, immediately upstream of the stricture, and in a proximal normal segment of bowel. Maximum bowel calibre (mm) and motility (Arbitrary units) at each ROI were calculated using previously validated software. Diameters and motility were compared using repeat measures anova and diameter correlated with motility score. In 21 subjects with follow-up MRE, ROIs were duplicated and percentage diameter and motility change across the two time points correlated.

KEY RESULTS

Mean diameter within the normal, prestricture and strictured bowel was 20, 30, and 15 mm (p < 0.001) with motility score 0.43, 0.28, and 0.15 AU, respectively (p < 0.001). There was a negative correlation between prestricture bowel diameter and motility (Pearson's R = -0.47, p < 0.001). For patients with follow-up MRE, there was a negative correlation between percentage change in prestricture diameter and motility, Spearman's Rho -0.6 p = 0.007.

CONCLUSIONS & INFERENCES

Quantified small bowel motility during MRE differs significantly between normal, prestricture, and strictured bowel. As prestricture bowel dilates, motility decreases, although this appears reversible in some.

Imaging techniques for assessment of inflammatory bowel disease: joint ECCO and ESGAR evidence-based consensus guidelines

The management of patients with IBD requires evaluation with objective tools, both at the time of diagnosis and throughout the course of the disease, to determine the location, extension, activity and severity of inflammatory lesions, as well as, the potential existence of complications. Whereas endoscopy is a well-established and uniformly performed diagnostic examination, the implementation of radiologic techniques for assessment of IBD is still heterogeneous; variations in technical aspects and the degrees of experience and preferences exist across countries in Europe. ECCO and ESGAR scientific societies jointly elaborated a consensus to establish standards for imaging in IBD using magnetic resonance imaging, computed tomography, ultrasonography, and including also other radiologic procedures such as conventional radiology or nuclear medicine examinations for different clinical situations that include general principles, upper GI tract, colon and rectum, perineum, liver and biliary tract, emergency situation, and the postoperative setting. The statements and general recommendations of this consensus are based on the highest level of evidence available, but significant gaps remain in certain areas such as the comparison of diagnostic accuracy between different techniques, the value for therapeutic monitoring, and the prognostic implications of particular findings.

Diffusion weighted MRI: overview and implications for rectal cancer management

Diffusion weighted imaging (DWI) is an MRI technique that quantifies the movement of water molecules at a cellular level. As the diffusion properties of water vary in areas of necrosis, high cellularity, inflammation and fibrosis, this technique is inherently sensitive to different pathologies. Having become a well-established adjunct to standard sequences during neurological MRI, technological advances have enabled extrapolation to abdominopelvic imaging, including staging of rectal cancer. Scan acquisitions can be performed rapidly using widely available equipment and consequently there has been rapid dissemination into routine practice. However, while DWI shows promise for detecting, staging and monitoring rectal cancer response to therapy, the evidence base remains scant with no current consensus for technical protocols, interpretation or integration into rectal cancer management. Moreover, those studies available to date have a small sample size and few observers, and their results may not be generalizable to daily practice. This article outlines the physical principles of DWI, reviews the literature and suggests avenues for future research into this important technical development.

An interview study analysing patients' experiences and perceptions of non-laxative or full-laxative preparation with faecal tagging prior to CT colonography

AIM

To compare patients' experiences of either non- or full-laxative bowel preparation with additional faecal tagging and subsequent computed tomographic (CT) colonography using in-depth interviews to elicit detailed responses.

MATERIALS AND METHODS

Patients who received CT colonography after non- (n = 9) or full-laxative (n = 9) preparation participated in a semi-structured telephone interview at least 2 days after the investigation. Full-laxative preparation consisted of magnesium citrate and sodium picosulphate administered at home (or polyethylene glycol, if contraindicated), followed by hospital-based faecal tagging with iohexol. Non-laxative preparation was home-based barium sulphate for faecal tagging. Interviews were transcribed and thematically analysed to identify recurrent themes on patients' perceptions and experiences.

RESULTS

Experiences of full-laxative preparation were usually negative and characterized by pre-test diarrhoea that caused significant interference with daily routine. Post-test flatus was common. Non-laxative preparation was well-tolerated; patients reported no or minimal changes to bowel habit and rapid return to daily routine. Patients reported worry and uncertainty about the purpose of faecal tagging. For iohexol, this also added burden from waiting before testing.

CONCLUSION

Patients' responses supported previous findings that non-laxative preparation is more acceptable than full-laxative preparation but both can be improved. Faecal tagging used in combination with laxative preparation is poorly understood, adding burden and worry. Home-based non-laxative preparation is also poorly understood and patients require better information on the purpose and mechanism in order to give fully informed consent. This may also optimize adherence to instructions. Allowing home-based self-administration of all types of preparation would prevent waiting before testing.

CT colonography in the English Bowel Cancer Screening Programme: national survey of current practice

AIM

To obtain information regarding the provision of computed tomography colonography (CTC) services to the National Health Service (NHS) Bowel Cancer Screening Programme (BCSP).

MATERIALS AND METHODS

Specialist screening practitioners at the 58 BCSP screening centres and lead BCSP radiologists at 110 hospitals performing CTC for the Programme were contacted and completed a semi-structured questionnaire administered by telephone. Responses were collated and descriptive statistics derived.

RESULTS

One hundred and seven (98%) SSPs and 103 (94%) radiologists were surveyed. All screening centres had access to CTC at 110 hospital sites. All sites used CTC for failed or contraindicated colonoscopy, 24% used it for patients taking anticoagulants, and 17% for those with fear of colonoscopy. Patient preference was not an indication at any site. Multidetector CT (100%), carbon dioxide insufflators (94%), and CTC software (95%) were almost universal. Ninety-one percent of radiographers and 98% of radiologists were trained in CTC image acquisition and interpretation, respectively. Seventy-five percent of the radiologists were gastrointestinal subspecialists and two-thirds had interpreted more than 300 examinations in clinical practice, although 5% had interpreted fewer than 100. Eighty-one percent of radiologists favoured some form of accreditation for CTC interpretation.

CONCLUSIONS

CTC is widely available to the BCSP. Appropriate hardware and software is almost ubiquitous. Most radiographers and radiologists offering CTC to the BCSP have received specific training. Formal service evaluation is patchy. The majority of radiologists would welcome national accreditation for CTC.

Quantitative MRI of colonic mural enhancement: segmental differences exist in endoscopically proven normal colon

OBJECTIVES

Abnormal contrast enhancement on MRI is advocated as a biomarker for inflammation in colitis, although the enhancement kinetics of normal colon are poorly described. Our purpose was to quantitatively assess mural enhancement in normal colon and test for intersegmental differences.

METHODS

Eight patients without prior history of inflammatory bowel disease underwent standard MRI colonography followed by normal same-day colonoscopy. Acquired sequences included a volumetric interpolated breath-hold examination (VIBE) to encompass the whole colonic volume, performed at 5°, 10° and 35° flip angles for T(1) quantitation and then at a fixed 35° flip angle three times prior to and every 30 s following intravenous gadoterate meglumine for 220 s. Ascending colon, descending colon and rectal R(1) (1/T(1)) was plotted against time. Mean pre-contrast R(1), initial change of R(1) (ΔR(1)), early and late "plateau phase" enhancement and the area under the R(1)-time (AUC-R(1)) curve were compared between segments using the Student's paired t-test.

RESULTS

There was no significant difference of pre-contrast R(1) between segments (p=0.49 to 0.62). ΔR(1) was higher for ascending colon compared with descending colon (0.0023±0.0012 ms(-1) vs 0.0010±0.0011 ms(-1), p=0.03). There was no significant difference for early or late plateau phase R(1) between colonic segments (p=0.08 to 1.00). AUC-R(1) was greater for ascending than descending colon (0.54±0.19 vs 0.30±0.14, p=0.03).

CONCLUSIONS

Intersegmental differences in colonic enhancement are present and should be considered when interpreting differential segmental enhancement.

CT enterography: review of technique and practical tips

CT enterography is a new non-invasive imaging technique that offers superior small bowel visualisation compared with standard abdomino-pelvic CT, and provides complementary diagnostic information to capsule endoscopy and MRI enterography. CT enterography is well tolerated by patients and enables accurate, efficient assessment of pathology arising from the small bowel wall or surrounding organs. This article reviews the clinical role of CT enterography, and offers practical tips for optimising technique and accurate interpretation.

Complications of CT colonography: a review

Since its inception, one of the main advantages of computed tomography colonography (CTC) over colonoscopy has been its assumed superior safety profile. However CTC is not without complication and adverse events are well described. Although the risks of insufflation, bowel preparation, contrast media and radiation dose are very small, they are not insignificant. This review discusses the potential hazards and complications associated with the technique, and discuss precautions, which may lessen the risk of occurrence.

MRI enterography: what is the clinical impact of unsuspected extra-enteric findings?

To define the incidence and nature of incidental extra-enteric findings on magnetic resonance enterography (MRE) following the introduction of a new clinical service, to assess the volume of additional tests generated and to gauge the potential of MRE to reduce the need for subsequent abdominal imaging. The imaging and patient records of 500 consecutive patients undergoing MRE at a single institution were reviewed. Note was made of patient demographics, any extra-enteric findings reported on the MRE, whether additional tests were recommended by the reporting radiologists to clarify or follow up extra-enteric findings and whether the patients underwent additional abdominal or pelvic imaging in the 4 months after the MRE. 64% of the cohort was male. The mean age was 45 years (range 11-80 years). Overall 190 (38%) underwent MRE for assessment of known Crohn's disease and 310 (62%) for other indications, such as abdominal pain and anaemia. 26 non-bowel-related extra-enteric abnormalities were noted on the MRE report in just 15 patients (3%), and a total of 6 additional tests were recommended by the reporting radiologist. 13 patients (2.6%) underwent some form of abdominal imaging within 4 months of the MRE. None of these additional investigations revealed any abnormality missed on the MRE. Extra-enteric findings are unlikely to have a significant impact on healthcare resources after the introduction of an MRE service.

Management of incidental findings during imaging research in "healthy" volunteers: current UK practice

OBJECTIVES

Incidental findings (IF) are becoming increasingly common due to the proliferation of imaging research. IFs can be life-changing for "healthy" volunteers. This study examined variation in IF management in UK research studies of healthy volunteers, including comparison with ethical and legal guidelines, thus providing baseline data and informing future practice.

METHODS

Questionnaire of participant background [medical/non-medical; radiologist/non-radiologist; years as principal investigator (PI)], type of research (involving children or not), institutional policy, volunteer information, radiologist involvement in reporting scans and IF disclosure mechanisms. Investigator's current and perceived "ideal" practice was examined. Participants were PIs performing imaging research of healthy volunteers approved by UK ethics committees (2006-2009).

RESULTS

63/146 (43%) surveys completed. 54/61 (88.5%) had site-specific guidelines. Information commonly provided to volunteers should IF be found: personal data (51/62; 82%), contingency plans (54/62; 87%) and disclosure to general practitioner (GP)/treating physician (47/62; 76%). PIs used different strategies for image review. Commonest: radiologist reports research scans only when researcher suspicious of IF [15/57 (26%) compared with 5/28 (16%) in ideal practice]. Commonest ideal reporting strategy: routine reporting by specialist radiologists [9/28 (29%) compared with 8/57 (14%) in current practice]. 49/56 (87.5%) have a standardised disclosure contingency plan, usually involving GP. PIs most commonly disclosed IFs to volunteers when judged relevant (27/58; 47%), most commonly face to face (22/54; 41%), by volunteer's GP (26/60; 43%). Background of PI influenced consent, reporting and disclosure practice.

CONCLUSION

There is wide variation in handling IFs in UK imaging research. Much of the current practice contravenes the vague existing legal and ethical guidelines, and is unlikely to be in the best interests of volunteers or researchers.

Patient experiences of MR colonography and colonoscopy: a qualitative study

OBJECTIVES

The aim of this study was to apply qualitative techniques to assimilate data on patient experience and attitudes during MR colonography (MRC) and colonoscopy (CC).

METHODS

18 patients (11 male, 8 female, median age 40.5 years), 10 of whom had known colonic inflammatory bowel disease (IBD) and 8 who were under investigation for suspected colonic neoplasia (non-IBD), underwent MRC and conventional CC. Semi-structured interviews were performed to assimilate test experiences and preferences, and themes were extracted using thematic analysis.

RESULTS

Thematic analysis identified three main themes: (i) physical experience, (ii) information provision and (iii) overall preference. Patients expressed mixed views about the physical experience of MRC but specifically identified water filling, breath holding and lying still as problematic. Anxiety was expressed regarding potential incontinence. Scanner noise interfered with the understanding of instructions, particularly amongst non-IBD patients. Non-IBD patients expressed greater anxiety over the delay in receiving the MRC report than IBD patients. In general MRI was considered as the more informative and safer investigation. Patients reported more physical discomfort during CC (notably IBD patients) related to air insufflation and colonoscopic manipulation but were more satisfied with the feedback they received. 10 patients (56%) stated an overall preference for MRC and 5 (28%) preferred CC. Reasons for preferences stated by the patients included discomfort, speed of the test, safety, perceived diagnostic ability and the ability to take biopsies.

CONCLUSION

Experiences of MRC and CC are complex and influenced by clinical indication. Individuals place different weightings on the relative importance of test attributes including discomfort, noise, immobility, feedback, safety and fear of incontinence and this defines overall preference.

Diagnostic and therapeutic impact of MR enterography in Crohn's disease

AIM

To assess the impact of magnetic resonance enterography (MRE) on clinician diagnostic confidence and therapeutic strategy in patients under investigation for small bowel Crohn's disease.

MATERIAL AND METHODS

Gastroenterologists completed a proforma before and following MRE in 51 patients (mean age 35 years, 26 female) under investigation for small bowel Crohn's disease, indicating percentage confidence for presence/absence of small bowel involvement. In suspected disease, diagnostic confidence (using a scoring system from 1=no to 6=yes) was scored for subcategories: extent >30 cm (DE), terminal ileum (lTI), jejunal (JD), colonic disease (CoD), strictures (ST), activity (AD), extraluminal complications (EL), and surgical need (NS). Therapeutic strategy was recorded. Patients were divided into three groups: 1=suspected disease, MRE normal (n=15); 2=suspected disease, MRE abnormal (n=30); 3=no suspected disease, MRE normal (n=6). Binomial exact and paired t-tests were use to compare confidence pre and post-MRE.

RESULTS

Mean percentage confidence for the presence/absence of small bowel disease increased from 62 to 84% (p=0.003), 87 to 98% (p=0.0001), and 83 to 98% (p=0.005) after MRE for groups 1, 2, and 3, respectively. In suspected disease, confidence changed significantly for all of the subcategories (p<0.001) except EL in group 1. The percentage of patients with a confidence change ranged from 40% (CoD) to 87% (lTI; group 1) and from 7% (EL) to 93% (DE; group 2). Therapeutic strategy changed in 31/51 (61%, 95% CI 47-74%), 14 with a reduction in planned therapy and 17 with an increase.

CONCLUSION

MRE had a positive diagnostic impact in patients under investigation for small bowel Crohn's disease and this influenced therapeutic strategy in 61% of the patients.

Use of small bowel imaging for the diagnosis and staging of Crohn's disease--a survey of current UK practice

OBJECTIVES

This study used a postal survey to assess the current use of small bowel imaging investigations for Crohn's disease within National Health Service (NHS) radiological practice and to gauge gastroenterological referral patterns.

METHODS

Similar questionnaires were posted to departments of radiology (n = 240) and gastroenterology (n = 254) identified, by the databases of the Royal College of Radiologists and British Society of Gastroenterologists. Questionnaires enquired about the use of small bowel imaging in the assessment of Crohn's disease. In particular, questionnaires described clinical scenarios including first diagnosis, disease staging and assessment of suspected extraluminal complications, obstruction and disease flare. The data were stratified according to patient age.

RESULTS

63 (27%) departments of radiology (20 in teaching hospitals and 43 in district general hospitals (DGHs)) and 73 (29%) departments of gastroenterology replied. These departments were in 119 institutions. Of the 63 departments of radiology, 55 (90%) routinely performed barium follow-though (BaFT), 50 (80%) CT, 29 (46%) small bowel ultrasound (SbUS) and 24 (38%) small bowel MRI. BaFT was the most commonly used investigation across all age groups and indications. SbUS was used mostly for patients younger than 40 years of age with low index of clinical suspicion for Crohn's disease (in 44% of radiology departments (28/63)). MRI was most frequently used in patients under 20 years of age for staging new disease (in 27% of radiology departments (17/63)) or in whom obstruction was suspected (in 29% of radiology departments (18/63)). CT was preferred for suspected extraluminal complications or obstruction (in 73% (46/63) and 46% (29/63) of radiology departments, respectively). Gastroenterological referrals largely concurred with the imaging modalities chosen by radiologists, although gastroenterologists were less likely to request SbUS and MRI.

CONCLUSION

BaFT remains the mainstay investigation for luminal small bowel Crohn's disease, with CT dominating for suspected extraluminal complications. There has been only moderate dissemination of the use of MRI and SbUS.

CT colonography: computer-assisted detection of colorectal cancer

OBJECTIVES

Computer-aided detection (CAD) for CT colonography (CTC) has been developed to detect benign polyps in asymptomatic patients. We aimed to determine whether such a CAD system can also detect cancer in symptomatic patients.

METHODS

CTC data from 137 symptomatic patients subsequently proven to have colorectal cancer were analysed by a CAD system at 4 different sphericity settings: 0, 50, 75 and 100. CAD prompts were classified by an observer as either true-positive if overlapping a cancer or false-positive if elsewhere. Colonoscopic data were used to aid matching.

RESULTS

Of 137 cancers, CAD identified 124 (90.5%), 122 (89.1%), 119 (86.9%) and 102 (74.5%) at a sphericity of 0, 50, 75 and 100, respectively. A substantial proportion of cancers were detected on either the prone or supine acquisition alone. Of 125 patients with prone and supine acquisitions, 39.3%, 38.3%, 43.2% and 50.5% of cancers were detected on a single acquisition at a sphericity of 0, 50, 75 and 100, respectively. CAD detected three cancers missed by radiologists at the original clinical interpretation. False-positive prompts decreased with increasing sphericity value (median 65, 57, 45, 24 per patient at values of 0, 50, 75, 100, respectively) but many patients were poorly prepared.

CONCLUSION

CAD can detect symptomatic colorectal cancer but must be applied to both prone and supine acquisitions for best performance.

Non-laxative CT colonography with barium-based faecal tagging: is additional phosphate enema beneficial and well tolerated?

OBJECTIVE

The purpose of this study was to investigate the efficacy and tolerance of an additional phosphate enema prior to non-laxative CT colonography (CTC).

METHODS

71 patients (mean age 80 years, 28 male, 43 female) underwent non-laxative CTC following 4 oral doses of diluted 2% w/w barium sulphate. Patients were invited to self-administer a phosphate enema 2 h before CTC. An experienced observer graded the volume of retained stool (1 (nil) to 4 (>75% bowel circumference coated)), retained fluid ((1 (nil) to 4 (>50% circumference obscured)), retained stool tagging quality (1 (untagged) to 5 (≥75% to 100%) tagged) and confidence a polyp ≥6 mm could be excluded (yes/no) for each of six colonic segments. Tolerance of the enema was assessed via questionnaire. Data were analysed between those using and not using the enema by Mann-Whitney and Fisher's exact test. 18/71 patients declined the enema.

RESULTS

There was no reduction in residual stool volume with enema use compared with non-use either overall (mean score 2.6 vs 2.7, p = 0.76) or in the left colon (mean 2.3 vs 2.4, p = 0.47). Overall tagging quality was no different (mean score 4.4 vs 4.3, p = 0.43). There was significantly more retained left colonic fluid post enema (mean score 1.9 vs 1.1, p<0.0001), and diagnostic confidence in excluding polyps was significantly reduced (exclusion not possible in 35% segments vs 21% without enema, p = 0.006). Of 53 patients, 30 (56%) found the enema straightforward to use, but 4 (8%) found it unpleasant.

CONCLUSION

Phosphate enema use prior to non-laxative CTC leads to greater retained fluid, reducing diagnostic confidence, and is not recommended.