Comparison of coronary flow reserve estimated by dynamic radionuclide SPECT and multi-detector x-ray CT.

Background: Recent technical advances in multi-detector computed tomography (MDCT) allow for assessment of coronary flow reserve (CFR). We compared regional CFR by dynamic SPECT and by dynamic MDCT in patients with suspected or known coronary artery disease (CAD).

Methods: Thirty-five patients, (29 males, mean age 69 years) with greater than average Framingham risk of CAD, underwent dipyridamole vasodilator stress imaging.

A mathematical model for the vessel recruitment in coronary microcirculation in the absence of active autoregulation.

This paper proposes a mathematical model for vessel recruitment in the microvascular coronary network. The model is based on microvascular network units (MVNUs), where we define a MVNU as a portion of the microvascular network comprising seven generations of identical, parallel-arranged vessels (upstream arteries, large and small arterioles, capillaries, small and large venules, and downstream veins). The model implements a new mechanism to describe the variation in the number of MVNU in response to sudden variations of the local input pressure.

Development of context dependency in human space perception.

Perception is a complex process, where prior knowledge exerts a fundamental influence over what we see. The use of priors is at the basis of the well-known phenomenon of central tendency: Judgments of almost all quantities (such as length, duration, and number) tend to gravitate toward their mean magnitude. Although such context dependency is universal in adult perceptual judgments, how it develops with age remains unknown.