[en] Systematic review to determine any association between imaging features of idiopathic mesenteric panniculitis (MP) and subsequent malignancy. Two researchers searched primary literature independently for imaging studies of MP. They extracted data focusing on methodology for unbiased patient accrual and capability to determine a link between MP and subsequent malignancy. They noted imaging features of MP. Data were accrued and meta-analysis intended. Fourteen of 675 articles were eligible; 1,226 patients. Only three (21 %) accrued patients prospectively. Twelve (86 %) studies described CT features. Follow-up varied widely; 1 month to 8 years. Prevalence of MP was influenced by accrual: 0.2 % for keyword search versus 1.7 % for consecutive series. Accrual bias affected nine (64 %) studies. 458 (38 %) of 1,209 patients had malignancy at accrual but varied widely (8-89 %), preventing meta-analysis. Sixty (6.4 %) of 933 patients developed new malignancy subsequently, also varying widely (0-11 %). Of just four studies that determined the proportion of unselected, consecutive patients with MP developing subsequent malignancy, three were retrospective and the fourth excluded patients with lymphadenopathy, likely excluding patients with MP. Studies were heterogeneous, with biased accrual. No available study can determine an association between MP and subsequent malignancy with certainty. (orig.)

[en] The development of the HADES code by Michael Norgett in the 1970s enabled, for the first time, the routine simulation of point defects in inorganic solids at the atomic scale. Using examples from current research we illustrate how the scope and applications of atomistic simulations have widened with time and yet still follow an approach readily identifiable with this early work. Firstly we discuss the use of the Mott-Littleton methodology to study the segregation of various isovalent cations to the (00.1) and (01.2) surfaces of haematite (α-Fe₂O₃). The results show that the size of the impurities has a considerable effect on the magnitude of the segregation energy. We then extend these simulations to investigate the effect of the concentration of the impurities at the surface on the segregation process using a supercell approach. We consider next the effect of segregation to stepped surfaces illustrating this with recent work on segregation of La³⁺ to CaF₂ surfaces, which show enhanced segregation to step edges. We discuss next the application of lattice dynamics to modelling point defects in complex oxide materials by applying this to the study of hydrogen incorporation into β-Mg₂SiO₄. Finally our attention is turned to a method for considering the surface energy of physically defective surfaces and we illustrate its approach by considering the low index surfaces of α-Al₂O₃

[en] To determine the importance placed by patients on attributes associated with whole-body MRI (WB-MRI) and standard cancer staging pathways and ascertain drivers of preference. Patients recruited to two multi-centre diagnostic accuracy trials comparing WB-MRI with standard staging pathways in lung and colorectal cancer were invited to complete a discrete choice experiment (DCE), choosing between a series of alternate pathways in which 6 attributes (accuracy, time to diagnosis, scan duration, whole-body enclosure, radiation exposure, total scan number) were varied systematically. Data were analysed using a conditional logit regression model and marginal rates of substitution computed. The relative importance of each attribute and probabilities of choosing WB-MRI-based pathways were estimated. A total of 138 patients (mean age 65, 61% male, lung n = 72, colorectal n = 66) participated (May 2015 to September 2016). Lung cancer patients valued time to diagnosis most highly, followed by accuracy, radiation exposure, number of scans, and time in the scanner. Colorectal cancer patients valued accuracy most highly, followed by time to diagnosis, radiation exposure, and number of scans. Patients were willing to wait 0.29 (lung) and 0.45 (colorectal) weeks for a 1% increase in pathway accuracy. Patients preferred WB-MRI-based pathways (probability 0.64 [lung], 0.66 [colorectal]) if they were equivalent in accuracy, total scan number, and time to diagnosis compared with a standard staging pathway. Staging pathways based on first-line WB-MRI are preferred by the majority of patients if they at least match standard pathways for diagnostic accuracy, time to diagnosis, and total scan number.

[en] To describe the MR imaging findings in adults presenting with anal incontinence following pull-through perineoplasty for anorectal atresia. 15 adults (12 male, 3 female; age 22-52 years) with anal incontinence following a prior perineal pull-through procedure as an infant for anorectal atresia were identified retrospectively. MR imaging was performed using either an endoanal coil or body coil. MR images were reviewed by three observers who noted whether pelvic floor and sphincter muscles were present and, if so, whether they were thinned or not. Data were tabulated and raw frequencies determined. Images were unavailable for one patient, leaving 14 for analysis. Anal stenosis prevented endoanal coil placement in 5. The pull-through was anatomically correct in 12 (86 %) patients but was misdirected in 2. Thinned muscle was seen in 11 (79 %) patients. External sphincter thinning was commonest (present in 10 patients), with levator plate thinning least common (present in 4 patients). Only one patient had thinning of all muscle groups. MR imaging may be used to determine the extent and quality of residual pelvic floor and anal sphincter muscle in adults who have functional disability following pull-through perineoplasty for anorectal agenesis. (orig.)

[en] A new electron-photon-ion(s) coincidence technique has enabled the discovery of new emissions from photoionization of N₂, NO, CO, CO₂, CS₂, OCS, N₂O, SO₂ and CF₄. For N₂O, we see evidence of fluorescence from the doubly charged ion to a dissociative state. For CS₂, an emission is found in coincidence with the stable doubly charged ion

[en] This volume builds on the success of the first edition of imaging pelvic floor disorders and is aimed at those practitioners with an interest in the imaging, diagnosis and treatment of pelvic floor dysfunction. Concise textual information from acknowledged experts is complemented by high-quality diagrams and images to provide a thorough update of this rapidly evolving field. Introductory chapters fully elucidate the anatomical basis underlying disorders of the pelvic floor. State of the art imaging techniques and their application in pelvic floor dysfunction are then discussed in detail. Additions since the first edition include consideration of the effect of aging and new chapters on perineal ultrasound, functional MRI and MRI of the levator muscles. The closing sections of the book describe the modern clinical management of pelvic floor dysfunction, including prolapse, urinary and faecal incontinence and constipation, with specific emphasis on the integration of diagnostic and treatment algorithms. (orig.)

[en] The aim of this study is to investigate the effect of changing sphericity filter values on performance of a computer assisted detection (CAD) system for CT colonography for data with and without fecal tagging. Colonography data from 138 patients with 317 validated polyps were divided into those with (86) and without (52) fecal tagging. Polyp coordinates were established by three observers and datasets analysed subsequently by a proprietary CAD system used at four discrete sphericity filter settings. Prompts were compared with the known coordinates in order to determine sensitivity and specificity. Sensitivity was highest at low sphericity; of 164 polyps 6 mm or more, 144 (87.8%) were detected at sphericity 0.3, and 132 (80.1%) at sphericity 0.9. Of 42 polyps measuring 10 mm or more, 40 (95.2%) were detected at sphericity 0.3, and 36 (85.7%) at sphericity 0.9. There was no significant difference in sensitivity for tagged and un-tagged data but specificity was reduced in tagged data at low sphericity and significantly reduced in untagged data at high sphericity. CAD had a sensitivity of 95.2% for polyps measuring 1 cm or more and 87.8% for polyps 6 mm or more when used at a sphericity setting of 0.3. Higher sphericity settings increased specificity while reducing sensitivity. The bowel preparation used significantly impacts on specificity. (orig.)

[en] This study investigated the variability in baseline computed tomography colonography (CTC) performance using untrained readers by documenting sources of error to guide future training requirements. Twenty CTC endoscopically validated data sets containing 32 polyps were consensus read by three unblinded radiologists experienced in CTC, creating a reference standard. Six readers without prior CTC training [four residents and two board-certified subspecialty gastrointestinal (GI) radiologists] read the 20 cases. Readers drew a region of interest (ROI) around every area they considered a potential colonic lesion, even if subsequently dismissed, before creating a final report. Using this final report, reader ROIs were classified as true positive detections, true negatives correctly dismissed, true detections incorrectly dismissed (i.e., classification error), or perceptual errors. Detection of polyps 1-5 mm, 6-9 mm, and ≥10 mm ranged from 7.1% to 28.6%, 16.7% to 41.7%, and 16.7% to 83.3%, respectively. There was no significant difference between polyp detection or false positives for the GI radiologists compared with residents (p=0.67, p=0.4 respectively). Most missed polyps were due to failure of detection rather than characterization (range 82-95%). Untrained reader performance is variable but generally poor. Most missed polyps are due perceptual error rather than characterization, suggesting basic training should focus heavily on lesion detection. (orig.)

[en] The effect of field of view on mucosal visualisation and reader efficiency during three-dimensional endoluminal CT colonography (CTC) was investigated. Twenty CTC datasets were reviewed at standard 90-degree and ''wide'' 140-degree viewing angles using customised viewing software (V3D colon; Viatronix), which listed number and size of missed mucosal areas (''missed regions tool'') and percentage mucosal visualisation. We compared: (1) unidirectional and bidirectional flythrough using 140- versus 90-degree viewing angles; (2) reader analysis time comparing unidirectional 140-degree flythrough versus bidirectional 90-degree flythrough; (3) paired image snapshots of 12 polyps taken at each field of view were reviewed to assess conspicuity. All patients underwent conventional colonoscopy. Bidirectional 140-degree review reduced the numbers of missed areas by between eight- and 40-fold depending on size category, including those >1,000 mm², compared with standard 90-degree bidirectional flythrough (P<0.001). Combined prone-supine unidirectional 140-degree flythrough and missed area review was 3.8 min faster than 90-degree bidirectional review (9.3 versus 5.5 min, P< 0.0001) for the same surface visualisation. When viewed as pairs, polyps were rated more conspicuous with a 90-degree field of view, P=0.03. Wide-angle (140-degree) CTC can reduce both numbers of missed areas and review times. However, this may be at the expense of polyp conspicuity. (orig.)

[en] Meta-analysis of data from studies of CT colonography suggests that it has excellent per-patient average sensitivity and average specificity for detection of adenomatous polyps and cancer. However, while its potential as a screening test is undoubted, there are several current limitations that will need to be overcome before it can be considered seriously by health policy makers. These revolve around issues of generalisability, which is inhibited most by a lack of trained observers and access to CT scanners, and a paucity of data relating to cost-effectiveness. Whether offering CT colonography as an alternative to competing strategies will genuinely enhance compliance also needs further and more detailed attention