CT imaging features and frequency of left ventricular myocardial fat in patients with CT findings of chronic left ventricular myocardial infarction.

AIM: To determine the frequency of left ventricular myocardial fat in patients with computed tomography (CT) findings of chronic left ventricular myocardial infarction, and to review the typical CT imaging features. MATERIALS AND METHODS: A retrospective search of the CT and nuclear scintigraphy reports from 1998-2005 for chronic left ventricular myocardial infarction was performed. The study group comprised those cases with available CT examinations revealing findings of chronic left ventricular myocardial infarction. Assessment for the presence of various imaging characteristics of left ventricular myocardial fat was performed in all cases. RESULTS: The frequency of left ventricular myocardial fat in 47 patients with CT evidence of chronic left ventricular myocardial infarction was 51%. Typical CT imaging features include thin linear or curvilinear fat attenuation within left ventricular myocardium, most commonly subendocardial, often associated with left ventricular wall thinning and/or calcification, predominantly in elderly men. CONCLUSIONS: Fat in the left ventricular myocardium is a common additional finding in patients with CT findings of chronic left ventricular myocardial infarction. The potential, but as yet unproven, use of this CT imaging finding is that the radiologist may be able to suggest a potential diagnosis of chronic left ventricular myocardial infarction on unenhanced, thick-section, non-gated or non-triggered chest CT imaging where identification of myocardial wall thinning may be difficult.

Effect of acute or repeated stress on behavior and brain norepinephrine system in Wistar-Kyoto (WKY) rats.

WKY rats develop more restraint-induced gastric ulcers and exhibit more depressive behavior compared to other rat strains. Exposure to novel stressors for 21 days exacerbates depressive behavior in WKY rats and alters beta-adrenoceptors (beta-ARs) and norepinephrine transporter (NET) sites in several limbic brain regions when compared to Sprague-Dawley rats. The present study examined whether these effects would be elaborated following an acute stressor and whether WKY rats would demonstrate adaptation after repeated stress. Rats were subjected to a 2-h supine restraint stress for either one or eight consecutive daily sessions. Open-field behavioral data were collected immediately after the daily stress sessions. Brains were sectioned for autoradiographic analysis of 125I-pindolol binding to beta-ARs and 3H-nisoxetine binding to NET sites in discrete brain regions. Acute 1-day stress resulted in a significant drop in body weight and an inhibition of behaviors in the open field. These effects were also sustained following 7 days of chronic restraint stress. In contrast, while acute stress had no effect on NET binding sites or beta-ARs, repeated stress decreased NET sites in the amygdala, hypothalamus, and locus coeruleus with little effect on beta-ARs in the brain regions examined.