stages) demonstrated that removing the effect by deconvolution of the bolus spread before reaching the myocardium is not necessary to maintain the relation between mean myocardial transit rate and LAD blood flow if the duration and site of the tracer injection are constant. Additionally, the coefficient of variation for determining the mean microbubble transit rate during MCE was 21% in these dogs (five injections at a single flow in each dog). We conclude that the transit rates of microbubbles during MCE can be used to assess regional myocardial blood flow in the in vivo beating heart as long as the blood volume remains constant. (Circ Res. 1994;74: 1157-1165 rates and hence regional myocardial blood flow. For this purpose, the myocardial transit rates of sonicated albumin microbubbles were compared with those of technetium-99m-labeled RBCs at different coronary blood flows in the dog. We also evaluated two additional issues in the present study: (1) whether, despite its theoretical advantages, fitting a lagged normal density function13 to the time-intensity plots provides better results than a gamma-variate function,14 which is simpler and less computer intensive, and (2) whether deconvolution of timeintensity curves using an input function is necessary when microbubble injection duration and site are constant. Materials and MethodsEighteen adult mongrel dogs were used for the study. The 12 group I dogs were used to (1) derive the relation between left anterior descending coronary artery (LAD) blood flow and mean RBC transit rate, (2) determine the correlation between mean microbubble and RBC transit rates, and (3) determine which function, lagged normal density or gamma variate, best describes the myocardial time-intensity data. The six group II dogs were used to (1) determine whether removing the effect by deconvolution of the bolus spread before reaching the myocardium is necessary to maintain the relation between mean myocardial transit rate and blood flow if the rate and site of tracer injection into a coronary artery are constant and (2) estimate the coefficient of variation for the mean myocardial

Thus, with adenosine-induced hyperemic flow, both 201Tl and sestamibi significantly underestimated the magnitude of the flow disparity between stenotic and normal perfusion beds. The degree of underestimation was greater for sestamibi. The clinical implication of these experimental findings for vasodilator perfusion imaging remains to be determined, since factors such as greater redistribution and scatter with 201Tl could offset its advantages.

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BackgroundCollecting patient reported outcome measures (PROMs) via computer-based electronic data capture system may improve feasibility and facilitate implementation in clinical care. We report our initial experience about the acceptability of touch-screen tablet computer-based, self-administered questionnaires among patients with chronic kidney disease (CKD), including stage 5 CKD treated with renal replacement therapies (RRT) (either dialysis or transplant).MethodsWe enrolled a convenience sample of patients with stage 4 and 5 CKD (including patients on dialysis or after kidney transplant) in a single-centre, cross-sectional pilot study. Participants completed validated questionnaires programmed on an electronic data capture system (DADOS, Techna Inc., Toronto) on tablet computers. The primary objective was to evaluate the acceptability and feasibility of using tablet-based electronic data capture in patients with CKD. Descriptive statistics, Fischer’s exact test and multivariable logistic regression models were used for data analysis.ResultsOne hundred and twenty one patients (55% male, mean age (± SD) of 58 (±14) years, 49% Caucasian) participated in the study. Ninety-two percent of the respondents indicated that the computer tablet was acceptable and 79% of the participants required no or minimal help for completing the questionnaires. Acceptance of tablets was lower among patients 70 years or older (75% vs. 95%; p = 0.011) and with little previous computer experience (81% vs. 96%; p = 0.05). Furthermore, a greater level of assistance was more frequently required by patients who were older (45% vs. 15%; p = 0.009), had lower level of education (33% vs. 14%; p = 0.027), low health literacy (79% vs. 12%; p = 0.027), and little previous experience with computers (52% vs. 10%; p = 0.027).ConclusionsTablet computer-based electronic data capture to administer PROMs was acceptable and feasible for most respondents and could therefore be used to systematically assess PROMs among patients with CKD. Special consideration should focus on elderly patients with little previous computer experience, since they may require more assistance with completion.Electronic supplementary materialThe online version of this article (10.1186/s12882-017-0771-7) contains supplementary material, which is available to authorized users.