Enhanced Grid-Based Visual Analysis of Retinal Layer Thickness with Optical Coherence Tomography

Optical coherence tomography enables high-resolution 3D imaging of retinal layers in the human eye. The thickness of the layers is commonly assessed to understand a variety of retinal and systemic disorders. Yet, the thickness data are complex and currently need to be considerably reduced prior to further processing and analysis. This leads to a loss of information on localized variations in thickness, which is important for early detection of certain retinal diseases. We propose an enhanced grid-based reduction and exploration of retinal thickness data. Alternative grids are computed, their representation quality is rated, and best fitting grids for given thickness data are suggested. Selected grids are then visualized, adapted, and compared at different levels of granularity. A visual analysis tool bundles all computational, visual, and interactive means in a flexible user interface. We demonstrate the utility of our tool in a complementary analysis procedure, which eases the evaluation of ophthalmic study data. Ophthalmologists successfully applied our solution to study localized variations in thickness of retinal layers in patients with diabetes mellitus

Impact of pulsatile pulmonary blood flow on cardiopulmonary exercise performance after the Fontan procedureCentral MessagePerspective

Objective: To evaluate the exercise capacity in patients following Fontan–Kreutzer, Fontan–Björk, and total cavopulmonary connection (TCPC). Methods: Patients who performed exercise capacity tests at least once after the Fontan procedure between 1979 and 2007 were included. Patients after Fontan–Björk procedure were divided into 2 groups according to the pulmonary blood flow (PBF) pattern: patients with pulsatile PBF and those without. Peak oxygen uptake (VO2) was measured and percent-predicted VO2 was calculated. Results: A total of 227 patients were nominated. The types of Fontan procedure included Fontan–Kreutzer in 48 (21.1%) patients, Fontan–Björk in 38 (16.7%); 11 (4.8%) with pulsatile PBF and 27 (11.9%) without pulsatile PBF; and TCPC in 141 (62.1%). Median age at the Fontan procedure was 4.5 years (interquartile range, 2.1-8.2 years). A total of 978 cardiopulmonary exercise tests were performed at median follow-up of 17.7 years (interquartile range, 11.3-23.4 years) postoperatively. Analysis using linear mixed-effects models demonstrated that percent-predicted VO2 was greater in patients with pulsatile PBF after Fontan–Björk compared with patients after other types of Fontan procedure (P < .001). The same results were obtained when the longitudinal percent predicted VO2 was performed using only patients with tricuspid atresia and double inlet left ventricle (P < .001). Conclusions: Among long-term survivors after various types of Fontan procedures, patients with pulsatile PBF after the Fontan–Björk procedure demonstrated better exercise performance compared to those after TCPC, those after the Fontan–Kreutzer procedure, and those after the Fontan-Björk procedure with non-pulsatile PBF. The results implicate the importance of pulsatile PBF to maintain the Fontan circulation