Diagnostic performance of sonographic activity scores for adult terminal ileal Crohn's disease compared to magnetic resonance and histological reference standards: experience from the METRIC trial.

OBJECTIVES: The simple ultrasound activity score for Crohn's disease (SUS-CD) and bowel ultrasound score (BUSS) are promising intestinal ultrasound (IUS) indices of CD, but studied mainly in small settings with few sonographers. We compared SUS-CD and BUSS against histological and magnetic resonance enterography (MRE) reference standards in a post hoc analysis of a prospective multicentre, multireader trial. METHODS: Participants recruited to the METRIC trial (ISRCTN03982913) were studied, including those with available terminal ileal (TI) biopsies. Sensitivity and specificity of SUS-CD and BUSS for TI CD activity were calculated with 95% confidence intervals (CI), from the prospective observations of the original METRIC trial sonographers against the histological activity index (HAI) and the simplified magnetic resonance index of activity (sMARIA). RESULTS: We included 284 patients (median 31.5 years, IQR 23-46) from 8 centres, who underwent IUS and MRE. Of these, 111 patients had available terminal ileal biopsies with HAI scoring. Against histology, sensitivity and specificity for active disease were 79% (95% CI 69-86%) and 50% (31-69%) for SUS-CD, and 66% (56-75%) and 68% (47-84%) for BUSS, respectively. Compared to sMARIA, the sensitivity and specificity for active CD were 81% (74-86%) and 75% (66-83%) for SUS-CD, and 68% (61-74%) and 85% (76-91%) for BUSS, respectively. The sensitivity of SUS-CD was significantly greater than that of BUSS against HAI and sMARIA (p < 0.001), but its specificity was significantly lower than of BUSS against the MRE reference standard (p = 0.003). CONCLUSIONS: Particularly when compared to MRE activity scoring, SUS-CD and BUSS are promising tools in a real-world clinical setting. CLINICAL RELEVANCE STATEMENT: When tested using data from a multicentre, multireader diagnostic accuracy trial, the simple ultrasound activity score for Crohn's disease (SUS-CD) and bowel ultrasound score (BUSS) were clinically viable intestinal ultrasound indices that were reasonably sensitive and specific for terminal ileal Crohn's disease, especially when compared to a magnetic resonance reference standard. KEY POINTS: The simple ultrasound activity score for Crohn's disease and bowel ultrasound score are promising intestinal ultrasound indices of Crohn's disease but to date studied mainly in small settings with few sonographers. Compared to histology and the magnetic resonance reference standard in a multicentre, multireader setting, the sensitivity of simple ultrasound activity score for Crohn's disease is significantly greater than that of bowel ultrasound score. The specificity of simple ultrasound activity score for Crohn's disease was significantly lower than that of bowel ultrasound score compared to the magnetic resonance enterography reference standard. The specificity of both indices was numerically higher when the magnetic resonance enterography reference standard was adopted.

Multivariable prognostic modelling to improve prediction of colorectal cancer recurrence: the PROSPeCT trial.

OBJECTIVE: Improving prognostication to direct personalised therapy remains an unmet need. This study prospectively investigated promising CT, genetic, and immunohistochemical markers to improve the prediction of colorectal cancer recurrence. MATERIAL AND METHODS: This multicentre trial (ISRCTN 95037515) recruited patients with primary colorectal cancer undergoing CT staging from 13 hospitals. Follow-up identified cancer recurrence and death. A baseline model for cancer recurrence at 3 years was developed from pre-specified clinicopathological variables (age, sex, tumour-node stage, tumour size, location, extramural venous invasion, and treatment). Then, CT perfusion (blood flow, blood volume, transit time and permeability), genetic (RAS, RAF, and DNA mismatch repair), and immunohistochemical markers of angiogenesis and hypoxia (CD105, vascular endothelial growth factor, glucose transporter protein, and hypoxia-inducible factor) were added to assess whether prediction improved over tumour-node staging alone as the main outcome measure. RESULTS: Three hundred twenty-six of 448 participants formed the final cohort (226 male; mean 66 ± 10 years. 227 (70%) had ≥ T3 stage cancers; 151 (46%) were node-positive; 81 (25%) developed subsequent recurrence. The sensitivity and specificity of staging alone for recurrence were 0.56 [95% CI: 0.44, 0.67] and 0.58 [0.51, 0.64], respectively. The baseline clinicopathologic model improved specificity (0.74 [0.68, 0.79], with equivalent sensitivity of 0.57 [0.45, 0.68] for high vs medium/low-risk participants. The addition of prespecified CT perfusion, genetic, and immunohistochemical markers did not improve prediction over and above the clinicopathologic model (sensitivity, 0.58-0.68; specificity, 0.75-0.76). CONCLUSION: A multivariable clinicopathological model outperformed staging in identifying patients at high risk of recurrence. Promising CT, genetic, and immunohistochemical markers investigated did not further improve prognostication in rigorous prospective evaluation. CLINICAL RELEVANCE STATEMENT: A prognostic model based on clinicopathological variables including age, sex, tumour-node stage, size, location, and extramural venous invasion better identifies colorectal cancer patients at high risk of recurrence for neoadjuvant/adjuvant therapy than stage alone. KEY POINTS: Identification of colorectal cancer patients at high risk of recurrence is an unmet need for treatment personalisation. This model for recurrence, incorporating many patient variables, had higher specificity than staging alone. Continued optimisation of risk stratification schema will help individualise treatment plans and follow-up schedules.

Simple changes to the reporting environment produce a large reduction in the frequency of interruptions to the reporting radiologist: an observational study.

BACKGROUND: Interruptions are a cause of discrepancy, errors, and potential safety incidents in radiology. The sources of radiological error are multifactorial and strategies to reduce error should include measures to reduce interruptions. PURPOSE: To evaluate the effect of simple changes in the reporting environment on the frequency of interruptions to the reporting radiologist of a hospital radiology department. MATERIAL AND METHODS: A prospective observational study was carried out. The number and type of potentially disruptive events (PDEs) to the radiologist reporting inpatient computed tomography (CT) scans were recorded during 20 separate 1-h observation periods during both pre- and post-intervention phases. The interventions were (i) relocation of the radiologist to a private, quiet room, and (ii) initial vetting of clinician enquiries via a separate duty radiologist. RESULTS: After the intervention there was an 82% reduction in the number of frank interruptions (PDEs that require the radiologist to abandon the reporting task) from a median 6 events per hour to 1 (95% confidence interval [CI] = 4-6; P < 0.00001). The overall number of PDEs was reduced by 56% from a median 11 events per hour to 5 (95% CI = 4.5-11: P < 0.00001). CONCLUSION: Relocation of inpatient CT reporting to a private, quiet room, coupled with vetting of clinician enquiries via the duty radiologist, resulted in a large reduction in the frequency of interruptions, a frequently cited avoidable source of radiological error.

Influence of oral contrast type and volume on patient experience and quality of luminal distension at MR Enterography in Crohn's disease: an observational study of patients recruited to the METRIC trial.

OBJECTIVES: To compare the distention quality and patient experience of oral mannitol and polyethylene glycol (PEG) for MRE. METHODS: This study is a retrospective, observational study of a subset of patients enrolled in a multicentre, prospective trial evaluating the diagnostic accuracy of MRE for small bowel Crohn's. Overall and segmental MRE small bowel distention, from 105 patients (64 F, mean age 37) was scored from 0 = poor to 4 = excellent by two experienced observers (68 [65%] mannitol and 37 [35%] PEG). Additionally, 130 patients (77 F, mean age 34) completed a questionnaire rating tolerability of various symptoms immediately and 2 days after MRE (85 [65%] receiving mannitol 45 [35%] receiving PEG). Distension was compared between agents and between those ingesting ≤ 1 L or > 1 L of mannitol using the test of proportions. Tolerability grades were collapsed into "very tolerable," "moderately tolerable," and "not tolerable." RESULTS: Per patient distension quality was similar between agents ("excellent" or "good" in 54% [37/68] versus 46% [17/37]) with mannitol and PEG respectively. Jejunal distension was significantly better with mannitol compared to PEG (40% [27/68] versus 14% [5/37] rated as excellent or good respectively). There was no significant difference according to the volume of mannitol ingested. Symptom tolerability was comparable between agents, although fullness following MRE was graded as "very tolerable" in 27% (12/45) of patients ingesting PEG, verses 44% (37/84) ingesting mannitol, difference 17% (95% CI 0.6 to 34%). CONCLUSION: Mannitol-based solutions and PEG generally achieve comparable distension quality and side effect profiles, although jejunal distension is better quality with mannitol. Neither distension quality nor side-effect profile is altered by ingestion of more than 1 L of mannitol. KEY POINTS: • Mannitol-based and PEG-based oral preparation agents generally achieve comparable distension quality for MRE with the exception of the jejunum which is better distended with mannitol. • Mannitol-based and PEG-based oral preparation agents used for MRE have similar side effect profiles. • Neither distension quality nor side-effect profile is altered by ingestion of more than 1 L of mannitol.

Renal Arteries Revisited: Anatomy, Pathologic Entities, and Implications for Endovascular Management.

The renal arteries (RAs) are important vessels that usually arise from the abdominal aorta and supply the kidneys; thus, these arteries play a vital role in physiologic functions such as hemofiltration and blood pressure regulation. An understanding of the basis for embryologic development and the frequently variable anatomy of the RAs is necessary to fully appreciate the range of diseases and the implications for procedural planning. Hemorrhage from an RA is relatively common and is typically traumatic or spontaneous, with the latter form often seen in association with underlying tumors or arteriopathy. Accurate diagnostic evaluation of RA disease due to conditions such as atherosclerosis, fibromuscular dysplasia, vasculitis, aneurysm, arteriovenous shunt, embolic disease, and dissection is dependent on the use of multimodality imaging and is essential for selecting appropriate clinical management, with endovascular therapy having a key role in treatment. Surgical considerations include extra-anatomic renal bypass, which remains an important treatment option even in this era of endovascular therapy, and RA embolization as an adjunct to tumor surgery. A novel area of research interest is the potential role of RA denervation in the management of refractory hypertension. ©RSNA, 2021.

Arterial Anatomy of the Anterior Abdominal Wall: Evidence-Based Safe Sites for Instrumentation Based on Radiological Analysis of 100 Patients.

Multiple medical interventions require percutaneous instrumentation of the anterior abdominal wall, all of which carry a potential for vascular trauma. We assessed the presence, position, and size of the anterior abdominal wall superior and inferior (deep) epigastric arteries to determine the safest site with respect to vascular anatomy of the rectus sheath. In a review of 100 arterial phase, contrast-enhanced abdominal computed tomography scans, anterior abdominal wall arteries were assessed bilaterally at three axial planes: transpyloric, umbilicus, and anterior superior iliac spine (ASIS). The mean age of patients was 69.2 years (SD ± 15), with 62 male and 38 female. An artery was visible least frequently at the transpyloric plane (5%), compared with the umbilicus (72-79%) and ASIS (93-96%), on the left (χ2 (4) = 207.272; P < 0.001) and right (χ2 (4) = 198.553; P < 0.001), with a moderate strength association (Cramer's V = 0.588 (left) and 0.575 (right)). The arteries were most commonly observed within the rectus abdominis muscle at the level of the umbilicus and ASIS on both sides (62-68%). The inferior epigastric artery was observed to be larger in diameter, start more laterally, and move medially as it travelled superiorly. These data suggest that the safest site to instrument the rectus sheath, with respect to vascular anatomy, is at the transpyloric plane. This information on anatomical variation of the anterior abdominal wall vasculature may be of particular interest to anesthetists performing rectus sheath block and surgeons during laparoscopic port insertion. Clin. Anat. 33:350-354, 2020. © 2019 Wiley Periodicals, Inc.

Magnetic resonance enterography, small bowel ultrasound and colonoscopy to diagnose and stage Crohn's disease: patient acceptability and perceived burden.

OBJECTIVES: To compare patient acceptability and burden of magnetic resonance enterography (MRE) and ultrasound (US) to each other, and to other enteric investigations, particularly colonoscopy. METHODS: 159 patients (mean age 38, 94 female) with newly diagnosed or relapsing Crohn's disease, prospectively recruited to a multicentre diagnostic accuracy study comparing MRE and US completed an experience questionnaire on the burden and acceptability of small bowel investigations between December 2013 and September 2016. Acceptability, recovery time, scan burden and willingness to repeat the test were analysed using the Wilcoxon signed rank and McNemar tests; and group differences in scan burden with Mann-Whitney U and Kruskal-Wallis tests. RESULTS: Overall, 128 (88%) patients rated MRE as very or fairly acceptable, lower than US (144, 99%; p < 0.001), but greater than colonoscopy (60, 60%; p < 0.001). MRE recovery time was longer than US (p < 0.001), but shorter than colonoscopy (p < 0.001). Patients were less willing to undergo MRE again than US (127 vs. 133, 91% vs. 99%; p = 0.012), but more willing than for colonoscopy (68, 75%; p = 0.017). MRE generated greater burden than US (p < 0.001), although burden scores were low. Younger age and emotional distress were associated with greater MRE and US burden. Higher MRE discomfort was associated with patient preference for US (p = 0.053). Patients rated test accuracy as more important than scan discomfort. CONCLUSIONS: MRE and US are well tolerated. Although MRE generates greater burden, longer recovery and is less preferred than US, it is more acceptable than colonoscopy. Patients, however, place greater emphasis on diagnostic accuracy than burden. KEY POINTS: • MRE and US are rated as acceptable by most patients and superior to colonoscopy. • MRE generates significantly greater burden and longer recovery times than US, particularly in younger patients and those with high levels of emotional distress. • Most patients prefer the experience of undergoing US than MRE; however, patients rate test accuracy as more importance than scan burden.

Exposure to contrast media in the perioperative period confers no additional risk of acute kidney injury in surgical patients.

Background: Iodinated contrast media (CM) used in angiography and computed tomography (CT) scans is an important cause of acute kidney injury (AKI) in hospitalized patients undergoing surgery. Contrast-induced nephropathy leads to AKI soon after CM administration. The aim of the study was to determine whether the timing of contrast media exposure related to diagnostic imaging during the immediate perioperative period influences the risk of post-operative AKI. Methods: All patients aged 18 years or above who underwent diagnostic imaging within 7 days of non-cardiac surgery between 1 January 2003 and 31 December 2013 in the Tayside region of Scotland, UK were included in the analysis. The primary outcome of AKI was defined using the Kidney Disease: Improving Global Outcomes creatinine-based criteria. Multiple logistic regressions were performed to identify predictors for AKI. Results: Of 9300 patients, 6224 were exposed to CM in the immediate perioperative period and 3076 were not. Post-operative AKI occurred in 678 (10.9%) of the 6224 patients who were exposed to CM. On multiple logistic regression, independent predictors of post-operative AKI were increasing age, male gender, lower baseline renal function and treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Timing of CM exposure did not affect risk of developing AKI, odds ratio 0.972 (95% confidence interval 0.935-1.010), P = 0.146. Conclusions: For patients who have either just had or are soon to undergo general surgical procedures there appears to be no need to limit CT scan quality by avoiding the administration of CM. These patients may benefit from the increased diagnostic utility of contrast-enhanced CT scans without increasing their risk of perioperative AKI.

High-Resolution Microscopy-Coil MR Imaging of Skin Tumors: Techniques and Novel Clinical Applications.

High-resolution magnetic resonance (MR) imaging performed with a microscopy coil is a robust radiologic tool for the evaluation of skin lesions. Microscopy-coil MR imaging uses a small surface coil and a 1.5-T or higher MR imaging system. Simple T1- and T2-weighted imaging protocols can be implemented to yield high-quality, high-spatial-resolution images that provide an excellent depiction of dermal anatomy. The primary application of microscopy-coil MR imaging is to delineate the deep margins of skin tumors, thereby providing a preoperative road map for dermatologic surgeons. This information is particularly useful for surgeons who perform Mohs micrographic surgery and in cases of nasofacial neoplasms, where the underlying anatomy is complex. Basal cell carcinoma is the most common nonmelanocytic skin tumor and has a predilection to manifest on the face, where it can be challenging to achieve complete surgical excision while preserving the cosmetic dignity of the patient. Microscopy-coil MR imaging provides dermatologic surgeons with valuable preoperative anatomic information that is not available at conventional clinical examination.

The celiac axis revisited: anatomic variants, pathologic features, and implications for modern endovascular management.

The celiac axis (CA) and its branches are critically important arteries that supply blood to the vital solid and hollow abdominal viscera of the foregut. There are many potential anatomic configurations, with up to half the population having a variation from the classic pattern of the CA bifurcating into the hepatosplenic trunk and left gastric artery. These configurations result from permutations in the fusion of the paired dorsal aortas during the first trimester. Despite the short length of the CA, it is affected by a wide range of pathologic conditions, including mesenteric ischemia due to intrinsic occlusion (secondary to causes such as atherosclerosis or thromboembolic events) and extrinsic compression from masses or the median arcuate ligament. Symptoms of mesenteric ischemia are nonspecific and include postprandial abdominal pain and weight loss; thus, the underlying pathologic condition may be found only when being sought specifically. More unusual pathologic conditions include dissection, aneurysms, and vascular malformations. Awareness of the pathologic conditions that affect the CA is important for both diagnostic and interventional radiologists. Early recognition and treatment of CA disease may prevent catastrophic hemorrhage and bowel infarction. Both endovascular and surgical approaches to treatment are greatly enhanced by correct identification of arterial anatomic variants; catheter angiography, computed tomographic angiography, and magnetic resonance angiography can facilitate detection of these variants. Knowledge of the different anatomic permutations is essential to guide endovascular procedures, such as hemorrhage control, transarterial interventional oncologic therapy, and treatment of visceral artery aneurysms. Online supplemental material is available for this article.

METRIC (MREnterography or ulTRasound in Crohn's disease): a study protocol for a multicentre, non-randomised, single-arm, prospective comparison study of magnetic resonance enterography and small bowel ultrasound compared to a reference standard in those aged 16 and over.

BACKGROUND: Crohn's disease (CD) is a lifelong, relapsing and remitting inflammatory condition of the intestine. Medical imaging is crucial for diagnosis, phenotyping, activity assessment and detecting complications. Diverse small bowel imaging tests are available but a standard algorithm for deployment is lacking. Many hospitals employ tests that impart ionising radiation, of particular concern to this young patient population. Magnetic resonance enterography (MRE) and small bowel ultrasound (USS) are attractive options, as they do not use ionising radiation. However, their comparative diagnostic accuracy has not been compared in large head to head trials. METRIC aims to compare the diagnostic efficacy, therapeutic impact and cost effectiveness of MRE and USS in newly diagnosed and relapsing CD. METHODS: METRIC (ISRCTN03982913) is a multicentre, non-randomised, single-arm, prospective comparison study. Two patient cohorts will be recruited; those newly diagnosed with CD, and those with suspected relapse. Both will undergo MRE and USS in addition to other imaging tests performed as part of clinical care. Strict blinding protocols will be enforced for those interpreting MRE and USS. The Harvey Bradshaw index, C-reactive protein and faecal calprotectin will be collected at recruitment and 3 months, and patient experience will be assessed via questionnaires. A multidisciplinary consensus panel will assess all available clinical and imaging data up to 6 months after recruitment of each patient and will define the standard of reference for the presence, localisation and activity of disease against which the diagnostic accuracy of MRE and USS will be judged. Diagnostic impact of MRE and USS will be evaluated and cost effectiveness will be assessed. The primary outcome measure is the difference in per patient sensitivity between MRE and USS for the correct identification and localisation of small bowel CD. DISCUSSION: The trial is open at 5 centres with 46 patients recruited. We highlight the importance of stringent blinding protocols in order to delineate the true diagnostic accuracy of both imaging tests and discuss the difficulties of diagnostic accuracy studies in the absence of a single standard of reference, describing our approach utilising a consensus panel whilst minimising incorporation bias. TRIAL REGISTRATION: METRIC - ISRCTN03982913 - 05.11.13.

Utility of a single early warning score in patients with sepsis in the emergency department.

BACKGROUND: An important element in improving the care of patients with sepsis is early identification and early intervention. Early warning score (EWS) systems allow earlier identification of physiological deterioration. A standardised national EWS (NEWS) has been proposed for use across the National Health Service in the UK. AIM: To determine whether a single NEWS on emergency department (ED) arrival is a predictor of outcome, either in-hospital death within 30 days or intensive care unit (ICU) admission within 2 days, in patients with sepsis. METHODS: Data were collected over a 3-month period as part of a national audit in 20 EDs in Scotland. All adult patients who were admitted for at least 2 days or who died within 2 days were screened for sepsis criteria. Patients with  systemic inflammatory response syndrome criteria were included. An EWS was calculated based on initial physiological observations made in the ED using the NEWS. RESULTS: Complete data were available for 2003 patients. Each rise in NEWS category was associated with an increased risk of mortality when compared to the lowest category (5-6: OR 1.95, 95% CI 1.21 to 3.14), (7-8: OR 2.26, 95% CI 1.42 to 3.61), (9-20: OR 5.64, 95% CI 3.70 to 8.60). This was also the case for the combined outcome (ICU and/or mortality). CONCLUSIONS: An increased NEWS on arrival at ED is associated with higher odds of adverse outcome among patients with sepsis. The use of NEWS could facilitate patient pathways to ensure triage to a high acuity area of the ED and senior clinician involvement at an early stage.

Influence of diffusion weighted imaging and contrast enhanced T1 sequences on the diagnostic accuracy of magnetic resonance enterography for Crohn's disease.

OBJECTIVES: To evaluate the additional diagnostic benefit of diffusion weighted imaging (DWI) and contrast enhanced (CE) images during MR enterography (MRE) of Crohn's disease. METHODS: Datasets from 73 patients (mean age 32; 40 male) (28 new-diagnosis, 45 relapsed) were read independently by two radiologists selected from a pool of 13. Radiologists interpreted datasets using three sequential sequence blocks: (1) T2 weighted and steady state free precession gradient echo (SSFP) images alone (T2^); (2) T2 weighted and SSFP images with DWI (T2 + DWI^) and; (3) T2 weighted images, SSFP, DWI and post-contrast enhanced (CE) T1 images (T2 + DWI + CE^), documenting presence, location, and activity of small bowel disease. For each sequence block, sensitivity and specificity (readers combined) was calculated against an outcome-based construct reference standard. RESULTS: 59/73 patients had small bowel disease. Per-patient sensitivity for disease detection was essentially identical (80 % [95 % CI 72, 86], 81 % [73,87], and 79 % [71,86] for T2^, T2 + DWI^and T2 + DWI + CE^respectively). Specificity was identical (82 % [64 to 92]). Per patient sensitivity for disease extent was 56 % (47,65), 56 % (47,65) and 52 % (43 to 61) respectively, and specificity was 82 % (64 to 92) for all blocks. Sensitivity for active disease was 97 % (90,99), 97 % (90,99) and 98 % (92,99), and specificity was also comparable between all sequence combination reads. Results were consistent across segments and newly diagnosed/relapse patients. CONCLUSION: There is no additional diagnostic benefit of adding either DWI or CE to T2 FSE and SSFP sequences for evaluating small bowel Crohn's disease, suggesting MRE protocols can be simplified safely.

Interventional radiology in acute pancreatitis: friend or foe?

CONTEXT: Peripancreatic fluid collections are known complications of pancreatitis. The majority of fluid collections can be drained percutaneously under radiological guidance. Although radiological percutaneous drainage is regarded as safe, here it resulted in catastrophic haemorrhage from the colon due to an iatrogenic injury. CASE REPORT: We present a case of a 70-year-old man who presented with acute alcohol-related severe necrotizing pancreatitis and an associated massive peripancreatic fluid collection. The drainage of this collection was attempted under computed tomography (CT) scan guidance. During the procedure the splenic artery and the splenic flexure of the colon were inadvertently damaged leading to life threatening per rectal bleeding requiring emergency angiographic embolisation of the splenic artery. CONCLUSION: Radiological drainage of peripancreatic fluid collections is generally regarded as having lower rates of complications compared to surgical necrosectomy. However, in this case it leads to a life threatening per rectal bleed requiring emergency splenic artery embolisation.

Systematic review and meta-analysis of prophylaxis use with intravenous contrast exposure to prevent contrast-induced nephropathy.

PURPOSE: Iodinated radiographic contrast media has been associated with an acute deterioration in renal function, termed contrast induced nephropathy (CIN). This review aims to establish the efficacy of prophylaxis interventions used in adult patients prior to intravenous exposure to iodinated contrast to reduce the risk of CIN. METHODS: An electronic search for published peer-reviewed articles was performed, supplemented with manual review of references from previous systematic reviews and the National Institute for Health and Care Excellence guidelines. Risk of bias was assessed using the Cochrane Collaboration's tool for assessing risk of bias. Random-effect meta-analyses were used to assess CIN incidence, need for kidney replacement therapy (KRT), mortality, fluid overload and persistent kidney dysfunction. RESULTS: 22 studies assessing a range of interventions were included in the qualitative analysis. The incidence of CIN was reduced by the use of N-acetylcysteine compared to a control group of saline (risk difference = -0.07, 95% CI -0.13 to -0.01) but not by sodium bicarbonate compared to control group of saline (risk difference = -0.02, 95% CI -0.04 to 0.01). Published studies give no indication that prophylactic interventions have significant impact on the need for KRT, mortality or persistent renal impairment. CONCLUSION: Evidence for prophylaxis against CIN in patients receiving intravenous iodinated contrast is limited. There was an association with the use of NAC with reduced incidence of CIN following intravenous contrast but there was no impact on other clinical outcomes assessed. The clinical significance of these findings remains unclear and further research focusing on these clinical outcomes is required.

Interobserver variation in the interpretation of magnetic resonance enterography in Crohn's disease.

OBJECTIVES: To evaluate interobserver variability for diagnosis of disease presence and extent of small bowel and colonic Crohn's disease using MR enterography (MRE). METHODS: Data from the first 73 consecutive patients (mean age 32, 33F, 28 new diagnosis, 45 suspected relapse) recruited to a multicentre, prospective diagnostic accuracy trial evaluating MRE for small bowel Crohn's disease were each read independently by three (from a pool of 20) radiologists. Radiologists documented presence and segmental location of small bowel Crohn's disease and recorded morphological mural/extramural parameters for involved segments. Per patient percentage agreement for disease presence and extent were calculated against an outcome-based construct reference standard (averaged between pairs of readers). Prevalence-adjusted bias-adjusted κ (PABAK) was calculated. RESULTS: Agreement for small bowel disease presence for new diagnosis/relapsed patients was 68%(κ = 0.36)/ 78% (κ = 0.56) and 43%(κ = 0.14)/ 53% for disease extent (κ = 0.07), respectively. For disease presence, all three radiologists agreed correctly with the reference standard in 41/59 (69%) of patients with small bowel involvement, and in 8/14 (57%) cases of without small bowel disease. Agreement was highest for multisegment disease, greater than 5 cm in length, with mural thickness>6 mm, and increased mural T2 signal. Agreement for colonic disease presence was 61% (κ = 0.21 fair agreement) for new diagnosis/ 60% (κ = 0.20, slight agreement) for relapsed patients. CONCLUSION: There is a reasonable agreement between radiologists for small bowel disease presence using MRE for newly diagnosed Crohn's disease, and patients with suspected relapse, respectively. Agreement is lower for disease extent. ADVANCES IN KNOWLEDGE: There is reasonable agreement between radiologists for small bowel disease presence using MRE for newly diagnosed (68%) Crohn's disease, and patients with suspected relapse (78%). Agreement is lower for disease extent (43% new diagnosis and 53% suspected relapse).

Endovascular simulator is of benefit in the acquisition of basic skills by novice operators.

PURPOSE: To determine whether an electronic endovascular simulator exhibited "construct validity," that is, the ability to differentiate between novice and experienced operators of differing levels of experience, and whether training on the simulator led to improved performance, thereby indicating "instructional effectiveness" for basic endovascular tasks. MATERIALS AND METHODS: Two separate experiments were performed by using an electronic endovascular simulator. In the first experiment, which was performed to investigate construct validity, the performance of four experienced operators and four novice radiology trainees was compared by using three objective outcome measures. In the second experiment, performed to investigate instructional effectiveness, the authors observed the performance of 14 novice operators before and after training on the device by using similar objective outcome measures as well as subjective measurement of performance from operator and supervisor. RESULTS: In the first experiment, one of the three simulator-derived objective outcome measures for the two subject groups was statistically significant and the other two approached statistical significance. In the second experiment, two of the three objective criteria and all subjective assessments of performance criteria showed a statistically significant improvement. CONCLUSIONS: The results indicate that the endovascular simulator exhibits both construct validity and instructional effectiveness for trainees at an early stage in their acquisition of these skills and support its use in the acquisition of basic endovascular skills.

MR enterographic manifestations of small bowel Crohn disease.

Magnetic resonance (MR) enterography is a clinically useful technique for the evaluation of both intraluminal and extraluminal small bowel disease, particularly in younger patients with Crohn disease. MR enterography offers the advantages of multiplanar capability and lack of ionizing radiation. It allows evaluation of bowel wall contrast enhancement, wall thickening, and edema, findings useful for the assessment of Crohn disease activity. MR enterography can also depict other pathologic findings such as lymphadenopathy, fistula and sinus formation, abscesses, and abnormal fold patterns. Even subtle disease manifestations may be detected when adequate distention of the small bowel is achieved, although endoscopic and double-contrast barium small bowel techniques remain superior in the depiction of changes in early Crohn disease (eg, aphthoid ulceration). Further research will be needed to determine whether MR imaging enhancement patterns may reliably help discriminate between active and inactive disease.

Magnetic resonance enterography compared with ultrasonography in newly diagnosed and relapsing Crohn's disease patients: the METRIC diagnostic accuracy study.

BACKGROUND: Magnetic resonance enterography and enteric ultrasonography are used to image Crohn's disease patients. Their diagnostic accuracy for presence, extent and activity of enteric Crohn's disease was compared. OBJECTIVE: To compare diagnostic accuracy, observer variability, acceptability, diagnostic impact and cost-effectiveness of magnetic resonance enterography and ultrasonography in newly diagnosed or relapsing Crohn's disease. DESIGN: Prospective multicentre cohort study. SETTING: Eight NHS hospitals. PARTICIPANTS: Consecutive participants aged ≥ 16 years, newly diagnosed with Crohn's disease or with established Crohn's disease and suspected relapse. INTERVENTIONS: Magnetic resonance enterography and ultrasonography. MAIN OUTCOME MEASURES: The primary outcome was per-participant sensitivity difference between magnetic resonance enterography and ultrasonography for small bowel Crohn's disease extent. Secondary outcomes included sensitivity and specificity for small bowel Crohn's disease and colonic Crohn's disease extent, and sensitivity and specificity for small bowel Crohn's disease and colonic Crohn's disease presence; identification of active disease; interobserver variation; participant acceptability; diagnostic impact; and cost-effectiveness. RESULTS: Out of the 518 participants assessed, 335 entered the trial, with 51 excluded, giving a final cohort of 284 (133 and 151 in new diagnosis and suspected relapse cohorts, respectively). Across the whole cohort, for small bowel Crohn's disease extent, magnetic resonance enterography sensitivity [80%, 95% confidence interval (CI) 72% to 86%] was significantly greater than ultrasonography sensitivity (70%, 95% CI 62% to 78%), with a 10% difference (95% CI 1% to 18%; p = 0.027). For small bowel Crohn's disease extent, magnetic resonance enterography specificity (95%, 95% CI 85% to 98%) was significantly greater than ultrasonography specificity (81%, 95% CI 64% to 91%), with a 14% difference (95% CI 1% to 27%). For small bowel Crohn's disease presence, magnetic resonance enterography sensitivity (97%, 95% CI 91% to 99%) was significantly greater than ultrasonography sensitivity (92%, 95% CI 84% to 96%), with a 5% difference (95% CI 1% to 9%). For small bowel Crohn's disease presence, magnetic resonance enterography specificity was 96% (95% CI 86% to 99%) and ultrasonography specificity was 84% (95% CI 65% to 94%), with a 12% difference (95% CI 0% to 25%). Test sensitivities for small bowel Crohn's disease presence and extent were similar in the two cohorts. For colonic Crohn's disease presence in newly diagnosed participants, ultrasonography sensitivity (67%, 95% CI 49% to 81%) was significantly greater than magnetic resonance enterography sensitivity (47%, 95% CI 31% to 64%), with a 20% difference (95% CI 1% to 39%). For active small bowel Crohn's disease, magnetic resonance enterography sensitivity (96%, 95% CI 92% to 99%) was significantly greater than ultrasonography sensitivity (90%, 95% CI 82% to 95%), with a 6% difference (95% CI 2% to 11%). There was some disagreement between readers for both tests. A total of 88% of participants rated magnetic resonance enterography as very or fairly acceptable, which is significantly lower than the percentage (99%) of participants who did so for ultrasonography. Therapeutic decisions based on magnetic resonance enterography alone and ultrasonography alone agreed with the final decision in 122 out of 158 (77%) cases and 124 out of 158 (78%) cases, respectively. There were no differences in costs or quality-adjusted life-years between tests. LIMITATIONS: Magnetic resonance enterography and ultrasonography scans were interpreted by practitioners blinded to clinical data (but not participant cohort), which does not reflect use in clinical practice. CONCLUSIONS: Magnetic resonance enterography has higher accuracy for detecting the presence, extent and activity of small bowel Crohn's disease than ultrasonography does. Both tests have variable interobserver agreement and are broadly acceptable to participants, although ultrasonography produces less participant burden. Diagnostic impact and cost-effectiveness are similar. Recommendations for future work include investigation of the comparative utility of magnetic resonance enterography and ultrasonography for treatment response assessment and investigation of non-specific abdominal symptoms to confirm or refute Crohn's disease. TRIAL REGISTRATION: Current Controlled Trials ISRCTN03982913. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 42. See the NIHR Journals Library website for further project information.

Crohn's disease is a waxing and waning lifelong inflammatory condition that affects the colon (large bowel) and small bowel. Treatment relies on accurately determining disease extent and underlying inflammation. Colonoscopy is very good for examining the colon, but it is invasive and, at best, can only visualise a few centimetres of the small bowel, so radiological imaging is very important. Magnetic resonance enterography (a type of magnetic resonance imaging scan) and ultrasonography are both radiological tests commonly performed in the NHS, and it is unclear which method is better. We performed a study to compare the accuracy of magnetic resonance enterography and ultrasonography for determining the extent of Crohn's disease in the bowel of participants newly diagnosed and in those participants with established Crohn's disease but with suspected deterioration. We also investigated how often radiologists agree with each other during test interpretation, the participant experience of undergoing the tests and their cost-effectiveness. We compared the tests in 284 participants (133 newly diagnosed and 151 with suspected deterioration). We found that both tests were accurate for detecting the presence (97% for magnetic resonance enterography and 92% for ultrasonography) and location (80% for magnetic resonance enterography and 70% for ultrasonography) of disease in the small bowel, but magnetic resonance enterography was better than ultrasonography for both (correctly classifying disease extent in 107 more participants for every 1000 participants with Crohn's disease). Magnetic resonance enterography was similarly better than ultrasonography at determining if the bowel was inflamed. The results were similar in newly diagnosed participants and those participants with suspected deterioration. Agreement between radiologists interpreting the same images was, at best, moderate for both tests. A total of 88% of participants tolerated magnetic resonance enterography well or fairly well, which was less than the percentage (99%) of participants who tolerated ultrasonography well or fairly well. Both tests had a similar effect on the treatment decisions made by doctors. Both tests were also similar in their value for money for the NHS.