Pulse sequence optimization for MR imaging using a paramagnetic hepatobiliary contrast agent

Paramagnetic agents enhance contrast between tissues in magnetic resonance (MR) imaging by altering tissue relaxation times. The effect of these changes on MR image intensity depends in part on the choice of operator-controlled pulse sequence parameters. With the newly described paramagnetic hepatobiliary contrast agent, iron(III) ethylenebis-(2-hydroxyphenylglycine), Fe(EHPG)-, an in vivo experimental analysis of pulse sequence optimization was performed on the rat. We compared the enhancement of the liver divided by background noise, EL/N, of standard inversion-recovery (IR) and spin-echo (SE) T1-weighted pulse sequences and several pulse sequences theoretically predicted to have improved EL/N. Optimization of the echo time (TE = TEmin) gave a substantial (greater than 60%) increase in EL/N over the standard IR and SE pulse sequences. Images obtained with optimized repetition rate and inversion time gave only a slight additional improvement. Within the uncertainties of our relaxation measurements, the measured changes in EL/N with pulse sequence optimization corresponded well with theoretical predictions. With the experimental and theoretical data, the importance of using a short echo time to obtain maximal T1 contrast in contrast-enhanced MR imaging and the relative merits of optimized SE versus IR pulse sequences for contrast-enhanced MR imaging are discussed.     

How cardiologists learn about echocardiography. A reminder for medical educators and legislators.

Mandatory continuing medical education, because of the need to validate participation, rewards classroom activities but not self-education. To determine if self-education is still a major study method for practicing physicians, we surveyed 158 cardiologists to learn how they first heard of, and continued their education in, echocardiography, a technique in which 81% of the physician-sample receiving no training in medical school, residency, or fellowship. Initial and continuing sources of information included professional journals and literature, meetings and conferences, discussion with colleagues, and courses. Professional journals ranked first in use; individual and group learning activities were used about equally by physicians. Recent legislation requiring validation of attendance may cause educators and legislators to ignore the self-learner. This study should remind educators and legislators that variations in learning style must be considered when planning and legislating approaches in continuing medical education.     

Self-focus and social evaluative threat increase salivary cortisol responses to acute stress in men

This experiment tested the hypothesis that self-focused attention might increase cortisol release. Social self-preservation theory suggests that social evaluation and associated feelings of shame are associated with cortisol reactivity, whereas one implication of objective self-awareness theory is that self-critical awareness and associated feelings of anxiety might be associated with increases in cortisol. 120 participants completed a public speech task either in front of an evaluative panel (social threat), in a non-evaluative setting while watching themselves in real-time on a television (self-focus), or in the mere presence of a non-evaluative person (control). Cortisol increased comparably among men in the social threat and self-focus conditions, but not among men in the control condition. There were no effects for women. Shame was correlated with increased cortisol in the social threat condition, whereas anxiety was correlated with increased cortisol in the self-focus condition. One broad implication of this work is that negative evaluation may increase cortisol regardless of whether this source comes from oneself or others.     

Role of fecal calprotectin as a biomarker of intestinal inflammation in inflammatory bowel disease

Calprotectin is an abundant neutrophil protein found in both plasma and stool that is markedly elevated in infectious and inflammatory conditions, including inflammatory bowel disease (IBD). We conducted a systematic review of the published literature regarding fecal calprotectin to evaluate its potential as a noninvasive marker of neutrophilic intestinal inflammation. Reference ranges for fecal calprotectin have been established in healthy adults and children, and elevated concentrations of fecal calprotectin have been demonstrated in numerous studies of patients with IBD. Fecal calprotectin correlates well with histological inflammation as detected by colonoscopy with biopsies and has been shown successfully to predict relapses and detect pouchitis in patients with IBD. Fecal calprotectin has been shown to consistently differentiate IBD from irritable bowel syndrome because it has excellent negative predictive value in ruling out IBD in undiagnosed, symptomatic patients. Fecal calprotectin also may be useful in determining whether clinical symptoms in patients with known IBD are caused by disease flares or noninflammatory complications/underlying irritable bowel syndrome and in providing objective evidence of response to treatment. Although more studies are needed to define fully the role of fecal calprotectin, convincing studies and growing clinical experience point to an expanded role in the diagnosis and management of IBD.