Objective: It is well documented that cognitive performance may be altered with altitude ascent, but the association of various cognitive performance tests with symptoms of Acute Mountain Sickness (AMS) is not well understood. Our objective was to assess and compare cognitive performance during a high altitude expedition using several tests and report the association of each test with AMS, headache, and quality of sleep. Methods: During an expedition to Mount Everest, three cognitive tests (Stroop, Trail Making, the RCAT, an inhouse developed motor accuracy test) were used along with a questionnaire to assess health and AMS. Eight team members were assessed pre-expedition, post-expedition and at several time points during the expedition. Results: There were no significant differences

Alveolar-capillary membrane conductance (DM,CO) and pulmonary-capillary blood volume (VC) are calculated via lung diffusing capacity for carbon monoxide (DLCO) and nitric oxide (DLNO) using the single breath, single oxygen tension (single-FiO2) method. However, two calculation parameters, the reaction rate of carbon monoxide with blood (θCO) and the DM,NO/DM,CO ratio (α-ratio), are controversial. This study systematically determined optimal θCO and α-ratio values to be used in the single-FiO2 method that yielded the most similar DM,CO and VC values compared to the ‘gold-standard’ multiple-FiO2 method. Eleven healthy subjects performed single breath DLCO/DLNO maneuvers at rest and during exercise. DM,CO and VC were calculated via the single-FiO2 and multiple-FiO2 methods by implementing seven θCO equations and a range of previously reported α-ratios. The RP θCO equation (Reeves and Park, Respiration physiology 88:1–21, 1992.) and an α-ratio of 4.0–4.4 yielded DM,CO and VC values that were most similar between methods. The RP θCO equation and an experimental α-ratio should be used in future studies.

Image processing tools combining thresholding, expansion, and convolution were the most useful for stool subtraction. Laxative-free colon examinations using barium for stool labeling can be performed at CT colonography with or without stool subtraction with high accuracy. Further study is warranted.

The purpose of this study was to prospectively examine vessel distensibility measurements by using electrocardiographically gated multidetector computed tomography (CT) in a phantom compared with measurements by using a digital camera and to examine feasibility in humans. Large-vessel phantoms were constructed, using a pulsatile flow pump, and absolute diameter and percentage diameter changes during pulsation were measured. After institutional review board approval and patient consent were obtained, the abdominal aorta of four patients was scanned with an electrocardiographically gated CT protocol. The mean difference in percentage diameter change between CT and optical measurements for the phantom ranged from -0.47% to 0.14%. The range of area changes in five locations along the abdominal aorta in four patients was 2.97%-37.16%. Findings of this study indicate that electrocardiographically gated CT angiography data reconstructed across cardiac phases permit measurements of large-vessel distensibility in a phantom model and that vessel distensibility measurement in humans may be possible.