Mathematical-morphology-based edge detection of retinal vessels in retinal images

Of all the important small and medium-sized blood vessels of the human body, retinal blood vessels are the only deep capillary that can be directly observed by a non-traumatic method. Retinal vascular morphology, such as vessel diameter, shape and distribution, is influenced by systemic diseases (Martinez-Perez, Hughes, Thom and Parker 2007). We can use digital fundus photography and analysis of retinal vascular morphology to find the relationship between the changes in vascular morphology and diabetes for the diagnosis of diseases. We aim at developing a retinal image processing system, that can analyze retinal images and provide helpful information for diagnosis. © 2013 Springer-Verlag.

Measurement of vein diameter for peripherally inserted central catheter (PICC) insertion: an observational study

Choosing an appropriately sized vein reduces the risk of venous thromboembolism associated with peripherally inserted central catheters. This observational study described the diameters of the brachial, basilic, and cephalic veins and determined the effect of patient factors on vein size. Ultrasound was used to measure the veins of 176 participants. Vein diameter was similar in both arms regardless of hand dominance and side. Patient factors-including greater age, height, and weight, as well as male gender-were associated with increased vein diameter. The basilic vein tended to have the largest diameter statistically. However, this was the case in only 55% of patients.

The catheter to vein ratio and rates of symptomatic venous thromboembolism in patients with a peripherally inserted central catheter (PICC): a prospective cohort study.

BACKGROUND: Peripherally inserted central catheters (PICCs) are a common vascular access device used in clinical practice. Their use may be complicated by adverse events such as venous thromboembolism (VTE). The size of the vein used for PICC insertion and thus the catheter to vein ratio is thought to be a controllable factor in the reduction of VTE rates in patients who have a PICC. However, an optimal catheter to vein ratio for PICC insertion has not previously been investigated to inform clinical practice. OBJECTIVES: To determine the effect of the catheter to vein ratio (proportion of the vein measured at the insertion point taken up by the catheter) on rates of symptomatic VTE in patients with a PICC and identify the optimal ratio cut-off point to reduce rates of this adverse event. METHOD: Adult patients waiting for PICC insertion at a large metropolitan teaching hospital were recruited between May and December 2013. Vein diameter at the PICC insertion site was measured using ultrasound with in-built callipers. Participants were followed up at eight weeks to determine if they developed symptomatic VTE. RESULTS: Data were available for 136 patients (50% cancer; 44% infection; 6% other indication for PICC). Mean age was 57 years with 54% males. There were four cases of confirmed symptomatic VTE (two involving the deep veins, one peripheral vein and one pulmonary embolism). Receiver operator characteristic (ROC) analysis determined that a 45% catheter to vein ratio was the ideal cut off point to maximise sensitivity and specificity (AUC 0.761; 95% CI 0.681-0.830). When a ratio of 46% or above was compared to one that was less than or equal to 45% using a log binomial generalised linear model it was found that participants with a catheter to vein ratio >45% were 13 times more likely to suffer VTE (relative risk 13, p=0.022; CI 1.445-122.788). CONCLUSION: It was found that a 45% catheter to vein ratio was the optimal cut off with high sensitivity and specificity to reduce the risk of VTE. However, further research is needed to confirm these results as although adequately powered; the number of cases of VTE was comparatively small, resulting in wide confidence intervals.

Vein measurement by peripherally inserted central catheter nurses using ultrasound: A reliability study

Background Peripherally inserted central catheters (PICCs) are increasingly inserted by trained registered nurses, necessitating the development of specialized skills such as the use of ultrasound. The selection of an adequately sized vein is an important factor in reducing adverse events such as deep vein thrombosis. However, PICC nurses may receive minimal training in the use of ultrasound for vein measurement. Objective We aimed to demonstrate the reliability of a vein measurement protocol using ultrasound by a PICC nurse trained in sonography. Methods The diameter of the basilic, brachial, and cephalic veins in the left arms of healthy participants (n = 12) were measured using ultrasound by a PICC nurse and a sonographer. A PICC nurse performed the measurement twice and the sonographer once; the PICC nurse's results were compared for intra-rater reliability and compared with the sonographer for inter-rater reliability. The results were analyzed using intraclass correlation coefficients (ICCs). Results Inter-rater reliability between the PICC nurse and the sonographer was adequate, the ICC for the brachial vein was 0.60 (95% confidence interval [CI], 0.06-0.87), basilic vein ICC was 0.87 (95% CI, 0.58-0.96) and cephalic vein ICC was 0.77 (95% CI, 0.39-0.93). Intra-rater reliability of the PICC nurse was higher; the ICC for the brachial vein was 0.80 (95% CI, 0.44-0.94), basilic vein ICC was 0.92 (95% CI, 0.67-0.98), and cephalic vein ICC was 0.78 (95% CI, 0.40-0.93). Conclusions Using a suitable protocol, a PICC nurse was able to measure vein diameter reliably when compared with a sonographer and consistently replicate these results.

Vein diameter for peripherally inserted cathether insertion: a scoping review

Background: The risk of venous thromboembolism (VTE) may be reduced if a vein of appropriate diameter is used forperipherally inserted central catheter (PICC) insertion. However, clinicians may have predilections to cannulate certainvein types and use particular insertion sites (eg, right or left arm) and therefore do not necessarily assess all veinsavailable to determine the most optimal vessel to introduce a catheter. It is important that clinicians have anunderstanding of the diameter of veins used for PICC insertion and the effect of patient factors such as hand dominanceon vein size to determine whether their clinical practice is appropriate.

Methods: A scoping review of published literature was performed to determine existing knowledge regarding thediameters of veins used for PICC insertion and the influence of patient factors such as hand dominance and laterality(left or right arm) on vein size.

Results: There was limited published research about the diameters of the basilic, brachial, and cephalic veins at themidupper arm, with only 6 studies identified. Three of the 6 selected articles focused on vein diameter measurement toinform arteriovenous fistula development. Only 1 study included participants undergoing PICC insertion. Scant researchexamined the effect of laterality on vein diameter and 1 study was identified that reported the influence of handdominance or vein type on the diameter of veins used for PICC insertion.

Conclusions: This review found that there is a paucity of studies that have examined the veins used for PICC insertion.Nevertheless, it appears that the basilic vein has the largest diameter (with smaller brachial and cephalic veins),although this is not always the case. Laterality and hand dominance does not seem to influence vein diameter. Furtherresearch about the vasculature used for PICC insertion is needed to inform clinical practice.