3D visualization and mapping of choroid thickness based on optical coherence tomography: A step-by-step geometric approach

Although bodily organs are inherently 3D, medical diagnosis often relies on their 2D representation. For instance, sectional images of the eye (especially, of its posterior part) based on optical coherence tomography (OCT) provide internal views, from which the ophthalmologist makes medical decisions about 3D eye structures. In the course, the physician is forced to mentally synthesize the underlying 3D context, which could be both time consuming and stressful. In this backdrop, can such 2D sections be arranged and presented in the natural 3D form for faster and stress-free diagnosis? In this paper, we consider ailments affecting choroid thickness, and address the aforementioned question at two levels-in terms of 3D visualization and 3D mapping. In particular, we exploit the spherical geometry of the eye, align OCT sections on a nominal sphere, and extract the choroid by peeling off inner and outer layers. At each step, we render our intermediate results on a 3D lightfield display, which provides a natural visual representation. Finally, the thickness variation of the extracted choroid is spatially mapped, and observed on a lightfield display as well as using 3D visualization softwares on a regular 2D terminal. Consequently, we identified choroid depletion around optic disc based on the test OCT images. We believe that the proposed technique would provide ophthalmologists with a tool for making faster diagnostic decisions with less stress

A simple and accurate matrix for model based photoacoustic imaging

Accurate model-based methods in Photo-Acoustic Tomography (PAT) can reconstruct the image from insufficient and inaccurate measurements. Most of the models either make the simplified assumption of spherical averaging or use accurate models that have computationally burdensome implementations. We present a simple and accurate measurement matrix that is derived from the pseudo-spectral PAT model. The accuracy of the measurement matrix is first validated against the experimental PAT signal. We also compare the model against the standard k-wave measurement model and the spherical averaging model. We then highlight several reconstruction strategies based on the nature of the region of interest to further demonstrate the accuracy of the proposed measurement matrix

Can an automated algorithm identify choriocapillaris in 2D-optical coherence tomography images?

This editorial considers the problem of automatic identification of choriocapillaris in 2D-optical coherence tomography images. Firstly, the major challenges in automating the process are presented. Subsequently, the authors present an overview of current methods in the automatic segmentation of 2D-optical coherence tomography images. Lastly, the authors close with a discussion on a recent algorithm for the automated identification of choriocapillaris based on the identification of the retinal pigment epithelial layer and the region in its immediate neighborhood, and its capabilities

Time associated with intravenous zoledronic acid administration in patients with breast or prostate cancer and bone metastasis

Akshara Richhariya1, Yi Qian2, Yufan Zhao2, Karen Chung11Amgen Inc, Global Health Economics, Thousand Oaks, CA, USA; 2Amgen Inc, Global Biostatistical Sciences, Thousand Oaks, CA, USAPurpose: Intravenous (IV) zoledronic acid (ZA) is commonly used to delay skeletal complications secondary to bone metastases. However, the time associated with ZA administration may represent a significant burden to healthcare providers and patients. This study assessed the time associated with IV ZA infusion in patients with bone metastases secondary to breast or prostate cancer (BC or PC) in the clinic setting.Methods: Eligible BC or PC patients with bone metastases scheduled to receive IV ZA were observed at seven US-based oncology clinics. Trained observers recorded the time for preinfusion tasks, ZA drug preparation, intravenous infusion, and follow-up activities.Results: Data are reported for 39 patients (BC: 24; PC: 15). Mean administration time was 69 (standard deviation [SD] 42) minutes for all patients combined, 72 (SD 47) minutes for BC, and 65 (SD 33) minutes for PC. Activity times were comparable between tumor types. Mean time for preinfusion tasks (eg, assessment of vital signs, blood draw) and ZA preparation were 12 (SD 20) minutes and 2 (SD 1) minutes, respectively. Mean time required for intravenous infusion (ZA infusion and hydration, when provided) and follow-up activities were 54 (SD 31) minutes and 2 (SD 1) minutes, respectively.Conclusion: Infusion time was the greatest time commitment associated with IV ZA administration, representing 78% of the total time on average. Time for preinfusion activities varied substantially. Overall, the mean time for ZA administration represents a notable time burden for healthcare providers and patients.Keywords: time and motion, bisphosphonates, zoledronic acid, intravenous administratio

Medical costs associated with cardiovascular events among high-risk patients with hyperlipidemia

Machaon M Bonafede,1 Barbara H Johnson,1 Akshara Richhariya,2 Shravanthi R Gandra2 1Outcomes Research, Truven Health Analytics, Cambridge, MA, USA; 2Global Health Economics, Amgen, Thousand Oaks, CA, USA Objectives: This study descriptively examined acute and longer term direct medical costs associated with a major cardiovascular (CV) event among high-risk coronary heart disease risk-equivalent (CHD-RE) patients. It also gives a firsthand look at fatal versus nonfatal CV events. Methods: The MarketScan® Commercial Claims and Encounters Database was used to identify adults with a CV event in 2006–2012 with hyperlipidemia or lipid-lowering therapy use in the 18 months prior to one of the following inpatient CV events: myocardial infarction, ischemic stroke, unstable angina, transient ischemic attack, percutaneous coronary intervention, or coronary artery bypass graft (CABG). Patients were required to have a preindex diagnosis of at least one of the following: peripheral arterial disease, abdominal aortic aneurysm, carotid artery disease, or diabetes. A subset analysis was conducted with patients with data linkable to the Social Security Administration Master Death File. Direct medical costs were reported for each quarter following a CV event, for up to 36 months after the first CV event. Results: In total, 38,609 CHD-RE patients were included, mean age 57 years, 31% female. CABG, myocardial infarction, and percutaneous coronary intervention were the most frequent and most expensive first CV events, accounting for >75% of all first CV events with mean first quarter costs ranging from $17,454 (nonfatal transient ischemic attack) to$125,690 (fatal CABG). Overall, 15% of those with a first CV event went on to have a second event during the 36-month study period with mean first quarter nonfatal and fatal costs similar to first event levels. Third CV events were rare, happening in less than 3% of patients. Conclusion: CV events among CHD-RE patients were costly regardless of sequence, averaging $47,433 in the first 90 days following an event and remaining high, never returning to preevent levels. When fatal, first CV event costs were 1.2 to 2.9 times higher than when nonfatal. Keywords: coronary heart disease risk equivalent, economic burden, subsequent CV event, fatal CV even

Validity of an automated algorithm for Choroidal Volume measurement

[Abstract is not Available

Patient-level costs of major cardiovascular conditions: a review of the international literature

Gina Nicholson,1 Shravanthi R Gandra,2 Ronald J Halbert,1 Akshara Richhariya,2 Robert J Nordyke1 1ICON, El Segundo, 2Amgen Inc., Thousand Oaks, CA, USA Objective: Robust cost estimates of cardiovascular (CV) events are required for assessing health care interventions aimed at reducing the economic burden of major adverse CV events. This review synthesizes international cost estimates of CV events.Methods: MEDLINE database was searched electronically for English language studies published during 2007-2012, with cost estimates for CV events of interest – unstable angina, myocardial infarction, heart failure, stroke, and CV revascularization. Included studies provided at least one estimate of patient-level direct costs in adults for any identified country. Information on study characteristics and cost estimates were collected. All costs were adjusted for inflation to 2013 values.Results: Across the 114 studies included, the average cost was US $6,466 for unstable angina,$11,664 for acute myocardial infarction, $11,686 for acute heart failure,$11,635 for acute ischemic stroke, $37,611 for coronary artery bypass graft, and$13,501 for percutaneous coronary intervention. The ranges for cost estimates varied widely across countries with US cost estimate being at least twice as high as European Union costs for some conditions. Few studies were found on populations outside the US and European Union.Conclusion: This review showed wide variation in the cost of CV events within and across countries, while showcasing the continuing economic burden of CV disease. The variability in costs was primarily attributable to differences in study population, costing methodologies, and reporting differences. Reliable cost estimates for assessing economic value of interventions in CV disease are needed. Keywords: cardiovascular diseases, health care costs, hospitalization economics, follow-up studie

Automated estimation of choroidal thickness distribution and volume based on OCT images of posterior visual section

A variety of vision ailments are indicated by anomalies in the choroid layer of the posterior visual section. Consequently, choroidal thickness and volume measurements, usually performed by experts based on optical coherence tomography (OCT) images, have assumed diagnostic significance. Now, to save precious expert time, it has become imperative to develop automated methods. To this end, one requires choroid outer boundary (COB) detection as a crucial step, where difficulty arises as the COB divides the choroidal granularity and the scleral uniformity only notionally, without marked brightness variation. In this backdrop, we measure the structural dissimilarity between choroid and sclera by structural similarity (SSIM) index, and hence estimate the COB by thresholding. Subsequently, smooth COB estimates, mimicking manual delineation, are obtained using tensor voting. On five datasets, each consisting of 97 adult OCT B-scans, automated and manual segmentation results agree visually. We also demonstrate close statistical match (greater than 99.6% correlation) between choroidal thickness distributions obtained algorithmically and manually. Further, quantitative superiority of our method is established over existing results by respective factors of 27.67% and 76.04% in two quotient measures defined relative to observer repeatability. Finally, automated choroidal volume estimation, being attempted for the first time, also yields results in close agreement with that of manual methods