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"Fleming, D. A"
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The efficacy of automated “disease/no disease” grading for diabetic retinopathy in a systematic screening programme
Aim:To assess the efficacy of automated “disease/no disease” grading for diabetic retinopathy within a systematic screening programme.Methods:Anonymised images were obtained from consecutive patients attending a regional primary care based diabetic retinopathy screening programme. A training set of 1067 images was used to develop automated grading algorithms. The final software was tested using a separate set of 14 406 images from 6722 patients. The sensitivity and specificity of manual and automated systems operating as “disease/no disease” graders (detecting poor quality images and any diabetic retinopathy) were determined relative to a clinical reference standard.Results:The reference standard classified 8.2% of the patients as having ungradeable images (technical failures) and 62.5% as having no retinopathy. Detection of technical failures or any retinopathy was achieved by manual grading with 86.5% sensitivity (95% confidence interval 85.1 to 87.8) and 95.3% specificity (94.6 to 95.9) and by automated grading with 90.5% sensitivity (89.3 to 91.6) and 67.4% specificity (66.0 to 68.8). Manual and automated grading detected 99.1% and 97.9%, respectively, of patients with referable or observable retinopathy/maculopathy. Manual and automated grading detected 95.7% and 99.8%, respectively, of technical failures.Conclusion:Automated “disease/no disease” grading of diabetic retinopathy could safely reduce the burden of grading in diabetic retinopathy screening programmes.
Journal Article
Costs and consequences of automated algorithms versus manual grading for the detection of referable diabetic retinopathy
AimsTo assess the cost-effectiveness of an improved automated grading algorithm for diabetic retinopathy against a previously described algorithm, and in comparison with manual grading.MethodsEfficacy of the alternative algorithms was assessed using a reference graded set of images from three screening centres in Scotland (1253 cases with observable/referable retinopathy and 6333 individuals with mild or no retinopathy). Screening outcomes and grading and diagnosis costs were modelled for a cohort of 180 000 people, with prevalence of referable retinopathy at 4%. Algorithm (b), which combines image quality assessment with detection algorithms for microaneurysms (MA), blot haemorrhages and exudates, was compared with a simpler algorithm (a) (using image quality assessment and MA/dot haemorrhage (DH) detection), and the current practice of manual grading.ResultsCompared with algorithm (a), algorithm (b) would identify an additional 113 cases of referable retinopathy for an incremental cost of £68 per additional case. Compared with manual grading, automated grading would be expected to identify between 54 and 123 fewer referable cases, for a grading cost saving between £3834 and £1727 per case missed. Extrapolation modelling over a 20-year time horizon suggests manual grading would cost between £25 676 and £267 115 per additional quality adjusted life year gained.ConclusionsAlgorithm (b) is more cost-effective than the algorithm based on quality assessment and MA/DH detection. With respect to the value of introducing automated detection systems into screening programmes, automated grading operates within the recommended national standards in Scotland and is likely to be considered a cost-effective alternative to manual disease/no disease grading.
Journal Article
Cost-effectiveness of implementing automated grading within the national screening programme for diabetic retinopathy in Scotland
Aims:National screening programmes for diabetic retinopathy using digital photography and multi-level manual grading systems are currently being implemented in the UK. Here, we assess the cost-effectiveness of replacing first level manual grading in the National Screening Programme in Scotland with an automated system developed to assess image quality and detect the presence of any retinopathy.Methods:A decision tree model was developed and populated using sensitivity/specificity and cost data based on a study of 6722 patients in the Grampian region. Costs to the NHS, and the number of appropriate screening outcomes and true referable cases detected in 1 year were assessed.Results:For the diabetic population of Scotland (approximately 160 000), with prevalence of referable retinopathy at 4% (6400 true cases), the automated strategy would be expected to identify 5560 cases (86.9%) and the manual strategy 5610 cases (87.7%). However, the automated system led to savings in grading and quality assurance costs to the NHS of £201 600 per year. The additional cost per additional referable case detected (manual vs automated) totalled £4088 and the additional cost per additional appropriate screening outcome (manual vs automated) was £1990.Conclusions:Given that automated grading is less costly and of similar effectiveness, it is likely to be considered a cost-effective alternative to manual grading.
Journal Article
Reliability of Physical Examination Items Used for Classification of Patients With Low Back Pain
The purpose of this study was to examine the interrater reliability of measurements obtained by examiners administering tests proposed to be important for classifying low back pain (LBP) problems.
Ninety-five subjects with LBP (41 men, 54 women) and 43 subjects without LBP (17 men, 26 women) were examined by 5 therapists trained in the techniques used.
A manual was developed by the first author that described the clinical examination procedures. The therapists were trained by the first author in the test procedures and definitions. The training included instruction through videotapes, practice and a written examination. Each examination was conducted by a pair of therapists. Within a pair, a therapist was the primary examiner for half of the subjects and an observer was the primary examiner for half of the subjects. Examination findings were recorded independently, without discussion.
Percentage of agreement and generalized kappa coefficients were used to analyzed the data. Kappa values were > or = .75 for all 28 items related to the symptoms elicited and > or = .40 for 72% of the 25 items related to alignment and movement.
The results suggest that experienced therapist who had trained together were able to agree on the results of examinations and obtain an acceptable level of reliability. Future work should focus on testing of reliability when more than one therapist performs the examination and when therapist not trained by the test developer to administer the examination perform the tests. [Van Dillen LR, Sahrmann SA, Norton BJ, et al. Reliability of physical examination items used for classification of patients with low back pain.
Journal Article
Corrosion of RoHS-Compliant Surface Finishes in Corrosive Mixed Flowing Gas Environments
Recently, the corrosion resistance of printed wiring board (PWB) finishes has generated considerable interest due to field failures observed in various parts of the world. This study investigates the corrosion issues associated with the different lead-free PWB surface finishes. Corrosion products on various PWB surface finishes generated in mixed flowing gas (MFG) environments were studied, and analysis techniques such as scanning electron microscopy, energy-dispersive x-ray, x-ray diffraction, focused ion beam, and scanning Auger microscopy were used to quantify the corrosion layer thickness and determine the composition of corrosion products. The corrosion on organic solderability preservative samples shows similar corrosion products to bare copper and is mainly due to direct attack of copper traces by corrosive gases. The corrosion on electroless nickel immersion gold occurs primarily through the porosity in the film and is accelerated by the galvanic potential between gold and copper; similar results were observed on immersion silver. Immersion tin shows excellent corrosion resistance due to its inherent corrosion resistance in the MFG environment as well as the opposite galvanic potential between tin and copper compared with gold or silver and copper.
Journal Article
Automated grading for diabetic retinopathy: a large-scale audit using arbitration by clinical experts
Background/aimsAutomated grading software has the potential to reduce the manual grading workload within diabetic retinopathy screening programmes. This audit was undertaken at the request of Scotland's National Diabetic Retinopathy Screening Collaborative to assess whether the introduction of automated grading software into the national screening programme would be safe, robust and effective.MethodsAutomated grading, performed by software for image quality assessment and for microaneurysm/dot haemorrhage detection, was carried out on 78 601 images, obtained from 33 535 consecutive patients, which had been manually graded at one of two regional diabetic retinopathy screening programmes. Cases where the automated grading software assessment indicated gradable images with no disease but the screening programme indicated ungradable images or disease more severe than mild retinopathy were arbitrated by seven senior ophthalmologists.Results100% (180/180) of patients with proliferative retinopathy, 100% (324/324) with referable background retinopathy, 100% (193/193) with observable background retinopathy, 97.3% (1099/1130) with referable maculopathy, 99.2% (384/387) with observable maculopathy and 99.8% (1824/1827) with ungradable images were detected by the software.ConclusionThe automated grading software operated to previously published results when applied to a large, unselected population attending two regional screening programmes. Manual grading workload reduction would be 36.3%.
Journal Article
The role of haemorrhage and exudate detection in automated grading of diabetic retinopathy
Background/aimsAutomated grading has the potential to improve the efficiency of diabetic retinopathy screening services. While disease/no disease grading can be performed using only microaneurysm detection and image-quality assessment, automated recognition of other types of lesions may be advantageous. This study investigated whether inclusion of automated recognition of exudates and haemorrhages improves the detection of observable/referable diabetic retinopathy.MethodsImages from 1253 patients with observable/referable retinopathy and 6333 patients with non-referable retinopathy were obtained from three grading centres. All images were reference-graded, and automated disease/no disease assessments were made based on microaneurysm detection and combined microaneurysm, exudate and haemorrhage detection.ResultsIntroduction of algorithms for exudates and haemorrhages resulted in a statistically significant increase in the sensitivity for detection of observable/referable retinopathy from 94.9% (95% CI 93.5 to 96.0) to 96.6% (95.4 to 97.4) without affecting manual grading workload.ConclusionAutomated detection of exudates and haemorrhages improved the detection of observable/referable retinopathy.
Journal Article
Clinic-Based Versus Outsourced Implementation of a Diabetes Health Literacy Intervention
ABSTRACT
BACKGROUND
We compared two implementation approaches for a health literacy diabetes intervention designed for community health centers.
METHODS
A quasi-experimental, clinic-randomized evaluation was conducted at six community health centers from rural, suburban, and urban locations in Missouri between August 2008 and January 2010. In all, 486 adult patients with type 2 diabetes mellitus participated. Clinics were set up to implement either: 1) a clinic-based approach that involved practice re-design to routinely provide brief diabetes education and counseling services, set action-plans, and perform follow-up without additional financial resources [CARVE-IN]; or 2) an outsourced approach where clinics referred patients to a telephone-based diabetes educator for the same services [CARVE-OUT]. The fidelity of each intervention was determined by the number of contacts with patients, self-report of services received, and patient satisfaction. Intervention effectiveness was investigated by assessing patient knowledge, self-efficacy, health behaviors, and clinical outcomes.
RESULTS
Carve-out patients received on average 4.3 contacts (SD = 2.2) from the telephone-based diabetes educator versus 1.7 contacts (SD = 2.0) from the clinic nurse in the carve-in arm (
p
< 0.001). They were also more likely to recall setting action plans and rated the process more positively than carve-in patients (
p
< 0.001). Few differences in diabetes knowledge, self-efficacy, or health behaviors were found between the two approaches. However, clinical outcomes did vary in multivariable analyses; carve-out patients had a lower HbA1c (
β
= −0.31, 95 % CI −0.56 to −0.06,
p
= 0.02), systolic blood pressure (
β
= −3.65, 95 % CI −6.39 to −0.90,
p
= 0.01), and low-density lipoprotein (LDL) cholesterol (
β
= −7.96, 95 % CI −10.08 to −5.83,
p
< 0.001) at 6 months.
CONCLUSION
An outsourced diabetes education and counseling approach for community health centers appears more feasible than clinic-based models. Patients receiving the carve-out strategy also demonstrated better clinical outcomes compared to those receiving the carve-in approach. Study limitations and unclear causal mechanisms explaining change in patient behavior suggest that further research is needed.
Journal Article