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SUMMARY: In the first part of this 2-part series, we described how to implement microscopy coil MR imaging of the orbits. Beyond being a useful anatomic educational tool, microscopy coil MR imaging has valuable applications in clinical practice. By depicting deep tissue tumor extension, which cannot be evaluated clinically, ophthalmic surgeons can minimize the surgical field, preserve normal anatomy when possible, and maximize the accuracy of resection margins. Here we demonstrate common and uncommon pathologies that may be encountered in orbital microscopy coil MR imaging practice and discuss the imaging appearance, the underlying pathologic processes, and the clinical relevance of the microscopy coil MR imaging findings.

Microscopy coil MR imaging of the orbits has been described previously as a technique for anatomic depiction. In the first part of this 2-part series, the improvement in spatial resolution that the technique offers compared with conventional MR imaging of the orbits is demonstrated. We provide a guide to implementing the technique, sharing pearls and pitfalls gleaned from our own practice to make implementation of microscopy coil MR imaging at your own center easy. As a quick reference guide to the small-scale structures encountered when reading the studies, a short anatomy section is included, which doubles as a showcase for the high-quality imaging that can be obtained. In the second part, our experience of microscopy coil MR imaging in day-to-day clinical practice takes it far beyond being a useful anatomic educational tool. Through a series of interesting cases, we highlight the added benefit of microscopy coil MR imaging compared with standard orbital MR imaging.

Introduction: 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. Materials & Methods: 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). Results: 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 to the umbilicus (72-79%) and ASIS (93-96%), on the left (χ (4) = 207.272; p

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.

Purpose Central venous access in children, in particular small children and infants, is challenging. We have developed a technique employing adult peripherally inserted central venous catheters (PICCs) as tunnelled central venous catheters (TCVCs) in children. The principal advantage of this novel technique is that the removal technique is less complex than that of conventional cuffed TCVCs. The catheter can be removed simply by being pulled out and does not require general anaesthesia. The purpose of this study is to determine the success, safety and utility of this technique and to identify the rate of late complications. We describe the 6-year experience in our unit. Materials and Methods Electronic and paper medical records were reviewed for consecutive paediatric patients who had a PICC device inserted as a TCVC over a 6-year period (September 2009 through July 2015). The following data were recorded—patient demographics, setting for PICC as TCVC insertion, use of ultrasound and fluoroscopy, PICC device type, early or late complications and date of and reason for removal. Results Twenty-one PICCs were inserted as TCVCs in 19 children, all aged less than 10 years. Mean patient age at the time of placement was 3.7 years. Average patient weight was 15.7 kg. All insertions were successful with no significant immediate complications recorded. The most common indication for insertion in our patient sample was pseudo-obstruction secondary to gastrointestinal dysmotility disorder (24%), with cystic fibrosis infective exacerbation being the second most frequent diagnosis (14%). Suspected catheter-related infection led to early device removal in one case (4.8%). Inadvertent dislodgement occurred in one case (4.8%). Nineteen of the 21 devices (90.4%) lasted for the total intended duration of use. Conclusion Using a PICC device as a TCVC in small children appears to be a safe technique, with an acceptable complication profile.

BackgroundMagnetic 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.ObjectiveTo 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.DesignProspective multicentre cohort study.SettingEight NHS hospitals.ParticipantsConsecutive participants aged ≥ 16 years, newly diagnosed with Crohn’s disease or with established Crohn’s disease and suspected relapse.InterventionsMagnetic resonance enterography and ultrasonography.Main outcome measuresThe 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.ResultsOut 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.LimitationsMagnetic 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.ConclusionsMagnetic 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 registrationCurrent Controlled Trials ISRCTN03982913.FundingThis project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full inHealth Technology Assessment; Vol. 23, No. 42. See the NIHR Journals Library website for further project information.

Magnetic resonance enterography (MRE) and ultrasound are used to image Crohn's disease, but their comparative accuracy for assessing disease extent and activity is not known with certainty. Therefore, we did a multicentre trial to address this issue. We recruited patients from eight UK hospitals. Eligible patients were 16 years or older, with newly diagnosed Crohn's disease or with established disease and suspected relapse. Consecutive patients had MRE and ultrasound in addition to standard investigations. Discrepancy between MRE and ultrasound for the presence of small bowel disease triggered an additional investigation, if not already available. The primary outcome was difference in per-patient sensitivity for small bowel disease extent (correct identification and segmental localisation) against a construct reference standard (panel diagnosis). This trial is registered with the International Standard Randomised Controlled Trial, number ISRCTN03982913, and has been completed. 284 patients completed the trial (133 in the newly diagnosed group, 151 in the relapse group). Based on the reference standard, 233 (82%) patients had small bowel Crohn's disease. The sensitivity of MRE for small bowel disease extent (80% [95% CI 72-86]) and presence (97% [91-99]) were significantly greater than that of ultrasound (70% [62-78] for disease extent, 92% [84-96] for disease presence); a 10% (95% CI 1-18; p=0·027) difference for extent, and 5% (1-9; p=0·025) difference for presence. The specificity of MRE for small bowel disease extent (95% [85-98]) was significantly greater than that of ultrasound (81% [64-91]); a difference of 14% (1-27; p=0·039). The specificity for small bowel disease presence was 96% (95% CI 86-99) with MRE and 84% (65-94) with ultrasound (difference 12% [0-25]; p=0·054). There were no serious adverse events. Both MRE and ultrasound have high sensitivity for detecting small bowel disease presence and both are valid first-line investigations, and viable alternatives to ileocolonoscopy. However, in a national health service setting, MRE is generally the preferred radiological investigation when available because its sensitivity and specificity exceed ultrasound significantly. National Institute of Health and Research Health Technology Assessment. [Abstract copyright: Copyright © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.]

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.

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.

Aim To produce short checklists of specific anatomical review sites for different regions of the body based on the frequency of radiological errors reviewed at radiology discrepancy meetings, thereby creating “evidence-based” review areas for radiology reporting. Materials and methods A single centre discrepancy database was retrospectively reviewed from a 5-year period. All errors were classified by type, modality, body system, and specific anatomical location. Errors were assigned to one of four body regions: chest, abdominopelvic, central nervous system (CNS), and musculoskeletal (MSK). Frequencies of errors in anatomical locations were then analysed. Results There were 561 errors in 477 examinations; 290 (46%) errors occurred in the abdomen/pelvis, 99 (15.7%) in the chest, 117 (18.5%) in the CNS, and 125 (19.9%) in the MSK system. In each body system, the five most common location were chest: lung bases on computed tomography (CT), apices on radiography, pulmonary vasculature, bones, and mediastinum; abdominopelvic: vasculature, colon, kidneys, liver, and pancreas; CNS: intracranial vasculature, peripheral cerebral grey matter, bone, parafalcine, and the frontotemporal lobes surrounding the Sylvian fissure; and MSK: calvarium, sacrum, pelvis, chest, and spine. Conclusion The five listed locations accounted for >50% of all perceptual errors suggesting an avenue for focused review at the end of reporting.

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.

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.

Summary points Most preventable deaths from trauma are caused by unrecognised and therefore untreated haemorrhage, particularly in the abdomen. Haemorrhage causes early deaths, and the associated hypovolaemic shock leads to secondary brain injury and contributes to late death from multiorgan failure.1 Early management is focused on resuscitation and the diagnosis and treatment of life threatening bleeding to prevent the lethal metabolic disturbance triad of acidosis, hypothermia, and coagulopathy.2 Many aspects of immediate trauma care suffer from a lack of high quality prospective research. This review is based predominantly on evidence from retrospective cohort series and is subject to the limitations inherent in this type of level 2 research.3 There are no prospective randomised controlled trials of interventional radiology in major trauma. Although the volume of level 2 evidence is substantial and contains few contradictory findings, no robust level 1 evidence yet exists. This review aims to summarise the evidence supporting the use of interventional radiological techniques in the management of haemorrhage caused by blunt abdominal trauma. Interventional radiology uses minimally invasive endovascular techniques to stem haemorrhage. Endovascular haemostasic techniques are established in non-trauma clinical scenarios. In trauma, the main application is to control endovascular haemorrhage by blocking bleeding vessels (transcatheter arterial embolisation (fig 1⇓) or relining …

A rapidly emerging clinical application of positron emission tomography (PET) is the detection of tumor tissue at whole-body studies performed with the glucose analogue 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG). High rates of recurrence after partial hepatic resection in patients with colorectal cancer liver metastases indicate that current presurgical imaging strategies are failing to show extrahepatic tumor deposits. Although FDG PET cannot match the anatomic resolution of conventional imaging techniques in the liver and the lungs, it is particularly useful for identification and characterization of extrahepatic disease. FDG PET can show foci of metastatic disease that may not be apparent at conventional anatomic imaging and can aid in the characterization of indeterminate soft-tissue masses. Several sources of benign and physiologic increased activity at FDG PET emphasize the need for careful correlation with findings of other imaging studies and clinical findings. FDG PET can improve the selection of patients for partial hepatic resection and thereby reduce the morbidity and mortality associated with inappropriate surgery.