Ansu Basu

Optic nerve head segmentation

Reliable and efficient optic disk localization and segmentation are important tasks in automated retinal screening. General-purpose edge detection algorithms often fail to segment the optic disk due to fuzzy boundaries, inconsistent image contrast or missing edge features. This paper presents an algorithm for the localization and segmentation of the optic nerve head boundary in low-resolution images (about 20 /spl mu//pixel). Optic disk localization is achieved using specialized template matching, and segmentation by a deformable contour model. The latter uses a global elliptical model and a local deformable model with variable edge-strength dependent stiffness. The algorithm is evaluated against a randomly selected database of 100 images from a diabetic screening programme. Ten images were classified as unusable; the others were of variable quality. The localization algorithm succeeded on all bar one usable image; the contour estimation algorithm was qualitatively assessed by an ophthalmologist as having Excellent-Fair performance in 83% of cases, and performs well even on blurred images.

Measurement of retinal vessel widths from fundus images based on 2-D modeling

Changes in retinal vessel diameter are an important sign of diseases such as hypertension, arteriosclerosis and diabetes mellitus. Obtaining precise measurements of vascular widths is a critical and demanding process in automated retinal image analysis as the typical vessel is only a few pixels wide. This paper presents an algorithm to measure the vessel diameter to subpixel accuracy. The diameter measurement is based on a two-dimensional difference of Gaussian model, which is optimized to fit a two-dimensional intensity vessel segment. The performance of the method is evaluated against Brinchmann-Hansens half height, Gregsons rectangular profile and Zhous Gaussian model. Results from 100 sample profiles show that the presented algorithm is over 30% more precise than the compared techniques and is accurate to a third of a pixel.

New treatment options for erectile dysfunction in patients with diabetes mellitus

Erection is a neurovascular event that involves spinal and supra spinal pathways. The final common pathway involves the release of nitric oxide (NO) from both endothelial cells and neurons, which acts as a vasodilator causing penile engorgement and erection. NO is degraded by the enzyme phosphodiesterase (PDE) type 5 in the penis.Erectile dysfunction (ED), defined as the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual performance, results when the neurovascular pathway is interrupted by medical conditions or drugs. A 15-item self-administered questionnaire, the International Index of Erectile Function (IIEF), is one of the most useful tools to evaluate erectile function (EF) in clinical trials, although of much less use in routine clinical practice.The MMAS (Massachusetts Male Aging Study) was the first major epidemiological investigation to study the prevalence of ED. The study found that ED was three times more common in patients with diabetes mellitus. The aetiopathogenesis of ED in diabetes is multifactorial, with vascular and neural factors being equally implicated. Hyperglycaemia is believed to give rise to biochemical perturbations that lead to these microvascular changes. In the MMAS, ED in diabetes was strongly correlated with glycaemic control, duration of disease and diabetic complications. The incidence increased with increasing age, duration of diabetes and deteriorating metabolic control, and was higher in individuals with type 2 diabetes than those with type 1.ED in men with diabetes often affects their quality of life and, as patients are often reluctant to come forward with their symptoms, a carefully taken history is one of the most useful approaches in identifying affected individuals.The PDE inhibitors have revolutionised the management of ED and oral drug therapy is currently first-line therapy for the condition. These agents act by potentiating the action of intracavernosal NO, thereby leading to a more sustained erection. Sildenafil was the first PDE5 inhibitor to undergo evaluation and has been studied extensively. More recently two other agents, vardenafil and tadalafil, have been introduced. All the drugs have been shown to be effective across a wide range of aetiologies of ED, including diabetes. The drugs have been shown to improve EF domain scores, penetration and maintenance of erection, resulting in more successful intercourse. Their effects are greater at higher doses. Sildenafil and vardenafil are shorter-acting agents, while tadalafil has a longer half-life allowing the user more flexibility in sexual activity. Common adverse effects include headache, nasal congestion and dyspepsia, all actions related to inhibition of PDE5. The drugs are generally well tolerated and withdrawal from the clinical studies as a result of drug-related adverse effects were rare. The use of PDE5 inhibitors in the presence of oral nitrates is absolutely contraindicated. The clinical studies to date have not evaluated the use of one drug in the case of treatment failure with another agent.Sublingual apomorphine, which stimulates central neurogenic pathways, is a new agent and may be a suitable alternative in those patients in whom PDE5 inhibitors are ineffective or contraindicated. In clinical trials, all IIEF domains except sexual desire were found to have improved after apomorphine. The median times to erection in these studies were 18.9 and 18.8 minutes for the 2 and 3mg doses, respectively.Intraurethral and intracavernosal alprostadil may be a useful alternative when oral drug therapy is ineffective or contraindicated. The management of ED in the diabetic patient may often involve a multidisciplinary approach where psychosexual counselling and specialist urologist advice is required in addition to the skills and expertise of the diabetologist. Finally, the introduction of the new oral agents have completely revolutionised the management of ED and allowed more individuals to come forward for treatment.

An automated retinal image quality grading algorithm

This paper introduces an algorithm for the automated assessment of retinal fundus image quality grade. Retinal image quality grading assesses whether the quality of the image is sufficient to allow diagnostic procedures to be applied. Automated quality analysis is an important preprocessing step in algorithmic diagnosis, as it is necessary to ensure that images are sufficiently clear to allow pathologies to be visible. The algorithm is based on standard recommendations for quality analysis by human screeners, examining the clarity of retinal vessels within the macula region. An evaluation against a reference standard data-set is given; it is shown that the algorithms performance correlates closely with that of clinicians manually grading image quality.

Automated diagnosis of referable maculopathy in diabetic retinopathy screening

This paper introduces an algorithm for the automated diagnosis of referable maculopathy in retinal images for diabetic retinopathy screening. Referable maculopathy is a potentially sight-threatening condition requiring immediate referral to an ophthalmologist from the screening service, and therefore accurate referral is extremely important. The algorithm uses a pipeline of detection and filtering of “peak points” with strong local contrast, segmentation of candidate lesions, extraction of features and classification by a multilayer perceptron. The optic nerve head and fovea are detected, so that the macula region can be identified and scanned. The algorithm is assessed against a reference standard database drawn from the Birmingham City Hospital (UK) diabetic retinopathy screening programme, against two possible modes of use: independent screening, and pre-filtering to reduce human screener workload.

The syndrome of inappropriate antidiuresis is associated with excess long-term mortality: a retrospective cohort analyses

Introduction The syndrome of inappropriate antidiuresis (SIAD) is the commonest cause of euvolaemic hyponatraemia in patients admitted to hospital. The mortality after discharge from hospital has not been previously studied in patients with SIAD. Aims To compare mortality in patients with SIAD and those with kidney injury (KI). To identify underlying diagnoses associated with deaths due to SIAD. Methods Single-centre retrospective cohort analyses of 804 patients with severe hyponatraemia over a 3-year period. Five-year survival data in patients with SIAD and those with KI were compared. The underlying diagnoses that contributed to SIAD in this cohort were analysed using ICD-10 codes. Results 202 patients had SIAD using biochemical cut-off parameters; 248 patients had KI. Patient with KI had a statistically significant (log-rank p<0.0001) shorter median survival time (2.24 months (95% CI 1.3 to 4.3)) compared with those with SIAD (31.0 months (95% CI 21.6 to 54.8)). 53.8% (n=78) of patients with hyponatraemia due to SIAD died within the first year after admission; the corresponding figure for those presenting with KI was 74.1% (n=166). Five years after admission, 80.8% (n=117) of those with SIAD had died; the corresponding figure for those with KI was 88.4% (n=200). In those patients with SIAD that died within the first year, malignancy appeared to be the most common cause (25.4%) followed by infection (23.8%). Conclusions Severe hyponatraemia in SIAD carries a high mortality after discharge, and although this seems often to be attributable to the underlying cause, the extent to which treatment with V2-recptor antagonists may help to correct the hyponatraemia associated with SIAD and influence the medium-to-long-term outcome in such patients is worthy of further study.

A rare case of carbimazole-induced hepatitis in a patient with Graves’ disease

Although carbimazole-induced hepatitis is rare, clinicians should be aware of this potential complication and offer alternative treatment early.

Audit of clinical practice in the use of incretin mimetic agents for the management of patients with type 2 diabetes

The objective of this audit was to compare treatment outcomes in patients on dipeptidyl peptidase (DPP)‐4 inhibitors and glucagon‐like peptide‐1 receptor (GLP‐1R) agonists within a hospital clinic setting, and to identify factors that might influence their response to treatment.The objective of this audit was to compare treatment outcomes in patients on dipeptidyl peptidase (DPP)-4 inhibitors and glucagon-like peptide-1 receptor (GLP-1R) agonists within a hospital clinic setting, and to identify factors that might influence their response to treatment. We undertook a retrospective audit of 118 consecutive patients who received either a DPP-4 inhibitor or a GLP-1R agonist as add-on to existing oral hypoglycaemic agent therapy. Primary clinical outcomes compared were change in HbA1c and weight. The clinical characteristics of patients who responded with both weight loss and improvement in HbA1c were compared to those who did not. The results showed that more patients (73.6%) were on a GLP-1R agonist; 57% of patients on a GLP-1R agonist lost weight and had improved HbA1c compared to 40% of patients on a DPP-4 inhibitor. The mean reduction in HbA1c was 8.4mmol/mol with a mean weight loss of 2.6kg. There were good correlations between the initial HbA1c and decline in HbA1c in both treatment groups. In all, 68.3% of patients on additional insulin treatment improved HbA1c while 46.3% improved in terms of both weight and HbA1c. Patients not on insulin responded better to treatment (OR 1.96; p=0.047) with these agents. It was concluded that good metabolic control can be achieved if these agents are used judiciously. The DPP-4 inhibitors improve HbA1c but are weight neutral, while the GLP-1R agonists cause both weight loss and improvements in HbA1c. The addition of insulin under specialist supervision can be beneficial. Copyright

Young Asian men with diabetes have the highest risk for acute coronary events: retrospective cohort analyses

Objective To understand the ethnic differences in coronary heart disease risk among inpatients with diabetes following acute coronary syndrome. Design Single-centre retrospective cohort-analysis of patients with type II diabetes over a six-year period receiving standard care. Setting Birmingham, UK. Participants One thousand and one hundred and five patients with type II diabetes from a multi-ethnic background. Main outcome measures Odds ratios of coronary heart disease events among three ethnic groups. Results The prevalence of coronary heart disease events was 20.7% in Asian, 13.2% in Caucasian and 7.7% in Afro-Caribbean patients. Asian patients were younger at diagnosis of diabetes (−5.1 years p < 0.001 versus Afro-Caribbeans and −7.1 years p < 0.001 versus Caucasians). The mean number of events was highest amongst Asian (1.2) compared to Caucasian (1.1) and Afro-Caribbean (1.0) patients (p = 0.04). The mean age at first event was 61.3 years for Asians, 62.5 years and 65.8 for Afro-Caribbeans and Caucasians, respectively (analysis of variance F[2,131] = 2.36 p = 0.09). Un-adjusted odds ratios for at least one coronary heart disease event were highest among Asian men (OR 5.04; 95% CI 2.31–11.01; p < 0.0001) with Afro-Caribbean women as baseline (OR 1.0). The odds ratios remain largely unchanged (1.0 Afro-Caribbeans [baseline], 1.27 [p = 0.56] Caucasians and 3.2 [p = 0.001] for Asians) when corrected for age, gender, duration of diabetes, insulin dependency, mean low-density lipoprotein-cholesterol, triglycerides and high-density lipoprotein-cholesterol, mean glycated haemoglobin, mean systolic and diastolic blood pressure (logistic regression; ROC: 79% AUC). Afro-Caribbean patients had the highest mean high-density lipoprotein-cholesterol (1.6 mmol/L) and the lowest risk for coronary heart disease events. Conclusions Asian patients were younger at their first event and diagnosed earlier with diabetes. Asian men had the highest risk of coronary heart disease event which correlated with the lowest levels of high-density lipoprotein-cholesterol.

Pregnancy outcome in women with gestational diabetes: results of a four‐year audit

The objective of this audit was to compare pregnancy outcome in women with gestational diabetes mellitus (GDM) managed with diet/lifestyle advice, versus those requiring additional insulin therapy.