Colon cancer screening with CT colonography: logistics, cost effectiveness, efficiency and progress

Colorectal cancer (CRC) incidence and mortality can be significantly reduced by population screening. Several different screening methods are currently in use, and this review focuses specifically on the imaging technique computed tomography colonography (CTC). The challenges and logistics of CTC screening, as well as the importance of test accuracy, uptake, quality assurance and cost-effectiveness will be discussed. With comparable advanced adenoma detection rates to colonoscopy (the most commonly used whole-colon investigation), CTC is a less invasive alternative, requiring less laxative, and with the potential benefit that it permits assessment of extra colonic structures. Three large-scale European trials have contributed valuable evidence supporting the use of CTC in population screening, and highlight the importance of selecting appropriate clinical management pathways based on initial CTC findings. Future research into CTC-screening will likely focus on radiologist training and CTC quality assurance, with identification of evidence-based key performance indicators that are associated with clinically-relevant outcomes such as the incidence of post-test interval cancers (CRC occurring after a presumed negative CTC). In comparison to other CRC screening techniques, CTC offers a safe and accurate option that is particularly useful when colonoscopy is contraindicated. Forthcoming cost-effectiveness analyses which evaluate referral thresholds, the impact of extra-colonic findings and real-world uptake will provide useful information regarding the feasibility of future CTC population screening

Imaging complex ventral hernias, their surgical repair, and their complications

Complex ventral hernia (CVH) describes large, anterior, ventral hernias. The incidence of CVH is rising rapidly due to increasing laparotomy rates in ever older, obese and co-morbid patients. Surgeons with a specific interest in CVH repair are now frequently referring these patients for imaging, normally computed tomography scanning. This review describes what information is required from preoperative imaging and the surgical options and techniques used for CVH repair, so that radiologists understand the postoperative appearances specific to CVH and are aware of the common complications following surgery. KEY POINTS: • Complex ventral hernia (CVH) describes large abdominal wall hernias (e.g. width ≥10cm). • CVH patients are being referred increasingly for preoperative and postoperative imaging. • Imaging is pivotal to characterise preoperative morphology and quantify loss of domain. • Postoperative imaging appearances are contingent on the surgical methods used for CVH repair. • Postoperative complications are depicted easily by imaging

Effectiveness of Training in CT Colonography Interpretation: Review of Current Literature

International guidance recommends that readers be specifically trained before embarking on independent interpretation of CT colonography (CTC) examinations. Systematic comparison of both international training requirements and the effectiveness of CTC training is lacking in the published literature. Therefore, we identified available international training standards for CTC and performed a review of studies published in the last 20 years to assess the impact of CTC interpretation training on reader diagnostic accuracy. A wide variation in training requirements was observed. Studies of the effectiveness of CTC reader training were heterogenous in methodology, with large variation in sample size and the type of training administered. Although training in CTC interpretation improves reader sensitivity overall, it has varying impact on specificity. Consensus agreement on the best way to train and assess readers in CTC interpretation may lead to lasting improvements in reader performance

Training in Computed Tomographic Colonography Interpretation: Recommendations for Best Practice

The value of computed tomographic colonography (CTC) as a sensitive diagnostic investigation for colorectal cancer is well established. However, there is lack of consensus in the best way to achieve expertise in interpreting these studies. In this review we discuss the value of CTC training, accreditation and performance monitoring; the qualities of good CTC interpretation training, and specific training cases with associated learning points

Ischaemic colitis: Practical challenges and evidence-based recommendations for management

Ischaemic colitis (IC) is a common condition with rising incidence, and in severe cases a high mortality rate. Its presentation, severity and disease behaviour can vary widely, and there exists significant heterogeneity in treatment strategies and resultant outcomes. In this article we explore practical challenges in the management of IC, and where available make evidence-based recommendations for its management based on a comprehensive review of available literature. An optimal approach to initial management requires early recognition of the diagnosis followed by prompt and appropriate investigation. Ideally, this should involve the input of both gastroenterology and surgery. CT with intravenous contrast is the imaging modality of choice. It can support clinical diagnosis, define the severity and distribution of ischaemia, and has prognostic value. In all but fulminant cases, this should be followed (within 48 hours) by lower gastrointestinal endoscopy to reach the distal-most extent of the disease, providing endoscopic (and histological) confirmation. The mainstay of medical management is conservative/supportive treatment, with bowel rest, fluid resuscitation and antibiotics. Specific laboratory, radiological and endoscopic features are recognised to correlate with more severe disease, higher rates of surgical intervention and ultimately worse outcomes. These factors should be carefully considered when deciding on the need for and timing of surgical intervention

3D printed ultrasound phantoms for clinical training

Ultrasound is a ubiquitous, portable structural imaging technique which is used to provide visual feedback for a range of diagnostic and surgical techniques. Training for these techniques demands a range of teaching models tailored for each application. Existing anatomical models are often overly simple or prohibitively expensive, causing difficulties in obtaining patient or procedure specific models. In this study we present ultrasonic rib phantoms for clinical teaching and training purposes, fabricated by three-dimensional (3D) printing technologies. Models were produced using freely available software and data, and their effectiveness as teaching phantoms evaluated using clinical ultrasound scans of the phantoms

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

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

Performance and evaluation in computed tomographic colonography screening: protocol for a cluster randomised trial

Background: Colorectal cancer (CRC) is a common, important healthcare priority and improving patient outcome relies on early diagnosis. Colonoscopy and computed tomographic colonography (CTC) are commonly-used diagnostic tests. Although colonoscopists are highly regulated and must be accredited, no analogous process exists for CTC. There are currently no universally accepted radiologist performance indicators for CTC, and lack of regulatory oversight may lead to variability in quality and lower neoplasia detection rates. This study aims to determine whether a structured educational training and feedback programme can improve radiologist interpretation accuracy. / Methods: NHS England CTC reporting radiologists will be cluster randomised to either an intervention (one-day individualised training and assessment with feedback) or control (assessment with no training or feedback) arm. Each cluster represents radiologists reporting CTC in a single NHS site. Both the intervention and control arm will undertake four CTC assessments at baseline, 1-month (after training; intervention arm or enrolment; control arm), 6- and 12 months to assess their detection of colorectal cancer (CRC) and 6mm+ polyps. The primary outcome will be difference in sensitivity at the 1-month test between arms. Secondary outcomes will include sensitivity at 6 and 12 months and radiologist characteristics associated with improved performance. Multilevel logistic regression will be used to analyse per-polyp and per-case sensitivity. Local ethical and Health Research Authority approval have been obtained. / Discussion: Lack of infrastructure to ensure that CTC radiologists can report adequately and lack of consensus regarding appropriate quality metrics may lead to variability in performance. Our provision of a structured education programme with feedback will evaluate the impact of individualised training and identify the factors related to improved radiologist performance in CTC reporting. An improvement in performance could lead to increased neoplasia detection and better patient outcome. / Registration: Clinical Trials (ClinicalTrials.gov Identifier: NCT02892721); available from: https://clinicaltrials.gov/ct2/show/NCT02892721. NIHR Clinical Research Network (CPMS ID 32293)

Effects of Intensive Late-Season Sheep Grazing Following Early-Season Steer Grazing on Population Dynamics of Sericea Lespedeza in the Kansas Flint Hills

Sericea lespedeza (Lespedeza cuneata; SL) is a high-tannin, invasive forb in the Tallgrass Prairie ecosystem. In Kansas, sericea lespedeza infests 980 square miles of pasture, primarily in the Flint Hills region. Sericea lespedeza infestations reduce native grass production by up to 92% through a combination of aggressive growth, prolific reproduction, canopy dominance, and chemical inhibition (allelopathy). Herbicides retard the spread of sericea lespedeza, but application is laborious and expensive; moreover, herbicides are lethal to ecologically-important, non-target plant species. Increased grazing pressure on sericea lespedeza by domestic herbivores may slow its spread and facilitate some measure of biological control. Unfortunately, mature plants contain high levels of condensed tannins, which are a strong deterrent to grazing by beef cattle. Small ruminants have greater tolerance for condensed tannins than beef cattle. Sheep, in particular, appear less susceptible to certain plant toxins than beef cattle and may be useful to selectively pressure noxious weeds like sericea lespedeza. The predominant grazing management practice in the Flint Hills region of Kansas involves annual spring burning followed by intensive grazing with yearling beef cattle from April to August. During seasonal grazing, 40 to 60% of annual graminoid production is removed and pastures remain idle for the remainder of the year. Under this prevailing management practice, invasion by sericea lespedeza into the Tallgrass Prairie biome has steadily increased. Sericea lespedeza flowers and produces seed in late summer from August to September. The absence of grazing pressure during this interval strongly promotes seed production, seed distribution, and continued invasion of the Flint Hills ecoregion by this noxious weed. Therefore, the objective of our study was to evaluate effects of late-season sheep grazing following locally-conventional steer grazing on vigor and reproductive capabilities of sericea lespedeza