Cardiac cycle is regulated by a complex interplay between autonomic nervous system and cardiac pacemaker cells. Decreased heart rate variability (HRV) and increased cardiac rhythm regularity are associated with poor prognosis in patients with systemic inflammation (e.g., sepsis). However, the underlying mechanism of decreased HRV in systemic inflammation is not understood. It is known that greater regularity in a complex system could indicate uncoupling of the system's components. The present study aimed to test the hypothesis that impaired responsiveness of cardiac pacemaker to autonomic nervous system may lead to uncoupling of the cardiovascular regulatory mechanisms during systemic inflammation. Systemic inflammation was induced by intraperitoneal injection of endotoxin (lipopolysaccharide, 1 mg/kg) in rats. Cardiovascular signals were recorded in conscious animals using a telemetric system. Heart rate dynamics was analyzed using Poincaré plot, and cardiac cycle regularity was assessed by sample entropy analysis. Spontaneously beating atria were isolated, and chronotropic responsiveness to adrenergic and cholinergic stimulation was assessed using standard organ bath. Sample entropy decreased significantly 4 h after endotoxin injection in conscious rats. Vagal modulation of cardiac cycle (as assessed by Poincaré plot) also exhibited a significant reduction in endotoxemic rats. Acute endotoxin challenge was associated with a significant hyporesponsiveness of isolated spontaneously beating atria to cholinergic stimulation. The chronotropic responsiveness to adrenergic stimulation was identical in controls and endotoxin-treated rats. These data propose that systemic inflammation is linked to reduced cardiac responsiveness to cholinergic stimulation. This may lead to partial uncoupling of cardiac pacemaker cells from autonomic neural control and can explain decreased HRV during systemic inflammation.

Fournier gangrene (FG) is a genitourinary necrotizing fasciitis that can be lethal if not promptly diagnosed and surgically debrided. The diagnosis is often made by physical examination paired with an appropriate clinical suspicion and supporting laboratory values. Imaging, particularly computed tomography (CT), plays a role in delineating involved fascial planes for operative debridement and occasionally in diagnosing FG. Less commonly, the imaging manifestations of FG may also be seen on ultrasound, radiographs, and magnetic resonance imaging. With the ubiquitous use and availability of CT, radiologists have a growing role in recognizing FG. This can be challenging in the absence of fascial gas, but a CT scoring system for necrotizing fasciitis can be helpful in making the diagnosis. Recent series suggest that this predominantly male disease has a rising incidence in women. Women with FG are more likely to be morbidly obese and have vulvar or labial involvement compared to men. Imaging mimics include ulcerative and necrotic tumors, traumatic or iatrogenic fascial gas, and vaginitis emphysematosa. The purpose of this pictorial review is to illustrate the imaging manifestations of FG and its mimics, with emphases on necrotizing fasciitis CT scoring systems and FG in women.

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OBJECTIVE. The objective of this study was to identify CT findings and determine interobserver reliability of surgically proven gastric volvulus. MATERIALS AND METHODS. This single-center retrospective study included 30 patients (21 women, nine men; mean age, 73 years old) with surgically proven gastric volvulus who underwent preoperative CT and 31 age- and sex-matched control subjects (21 women, nine men; mean age, 74 years old) with large hiatal hernias who were imaged for reasons other than abdominal pain. Two blinded radiologists reviewed the CT images and recorded findings of organoaxial and mesenteroaxial gastric volvulus and ischemia. Interobserver reliability, reader accuracy, sensitivity, specificity, and likelihood ratios of each CT finding were calculated. RESULTS. The radiologists were overall 90% accurate (55/61; six false-negatives per reader) in identifying gastric volvulus. Interobserver agreement was substantial (κ = 0.71) for identifying the presence or absence of gastric volvulus. Agreement for most CT findings of gastric volvulus (11/14, 79%) was excellent (5/14, 36%) or substantial (6/14, 43%); the remaining findings showed moderate agreement (3/14, 21%). The most frequent and sensitive CT findings of volvulus with high positive likelihood ratios were stenosis at the hernia neck (reader 1, sensitivity = 80%, positive likelihood ratio = 26.66; reader 2, sensitivity = 77%, positive likelihood ratio = 12.83) and transition point at the pylorus (reader 1, sensitivity = 80%, positive likelihood ratio = 17; reader 2, sensitivity = 70%, positive likelihood ratio = 15). The presence of perigastric fluid or a pleural effusion were significantly more frequent in patients with ischemia at surgical pathology (p < 0.05 in all comparisons, both radiologists). CONCLUSION. In our series, CT showed substantial interobserver agreement and fair accuracy in identifying the presence of gastric volvulus.

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