The ability to accurately and noninvasively quantify fatty infiltration in organs such as the liver and the pancreas remains a critical component in understanding the link between obesity and its comorbidities such as type 2 diabetes and fatty liver disease. Single‐voxel (1H) proton magnetic resonance spectroscopy (MRS) has long been regarded as the gold‐standard noninvasive technique for such measurements. Recent advances in three‐dimensional fat–water magnetic resonance imaging (MRI) methods have led to the development of rapid, robust, and quantitative approaches that can accurately characterize the proportion of fat and water content in underlying tissues across the full imaging volume, and hence entire organs of interest. One such technique is called IDEAL (Iterative Decomposition with Echo Asymmetry and Least squares estimation). This article prospectively compares three‐dimensional (3D) IDEAL‐MRI and single‐voxel MRS in the assessment of hepatic (HFF) and pancreatic fat fraction (PFF) in 16 healthy subjects. MRS acquisitions took 3–4 min to complete whereas IDEAL acquisitions were completed in 20‐s breath‐holds. In the liver, there was a strong correlation (slope = 0.90, r2 = 0.95, P < 0.001) between IDEAL and MRS‐based fat fractions. In the pancreas, a poorer agreement between IDEAL and MRS was observed (slope = 0.32, r2 = 0.51, P < 0.02). The discrepancy of PFF is likely explained by MRS signal contamination from surrounding visceral fat, presumably during respiratory motion. We conclude that IDEAL is equally accurate in characterizing hepatic fat content as MRS, and is potentially better suited for fat quantification in smaller organs such as the pancreas.

Adipose tissue secretes adiponectin, an adipocytokine that is involved in the regulation of insulin sensitivity. Following acute exercise, insulin sensitivity has been shown to increase. Increased adiponectin following exercise may be related to the change in insulin sensitivity. The purpose of the present study was to characterize the effect of a single cycle exercise session on adiponectin and to compare the exercise effects between healthy male and female subjects. Plasma concentrations of adiponectin, tissue necrosis factor-alpha (TNF-alpha), insulin, glucose, and leptin were assessed before and immediately after a 60-minute stationary cycle ergometry session at 65% of Vdot;O(2max). Male and female subjects were matched for cardiorespiratory fitness and body composition and dietary intake was controlled for the three days prior to the exercise trial. At rest, adiponectin concentration was not associated with percentage body fat, body mass index (BMI), fitness, or resting plasma variables ( P>0.05). Following exercise, neither male nor female subjects exhibited changes in adiponectin or leptin concentrations ( P>0.05). TNF-alpha exhibited a time main effect increase with exercise ( P<0.05), but there were no gender differences. These results suggest that plasma adiponectin concentrations do not change with exercise in healthy male or female subjects. Results are given as mean (SE).

Background-We previously reported that 20% of women with chest pain but without obstructive coronary artery disease (CAD) had stress-induced reduction in myocardial phosphocreatine-adenosine triphosphate ratio by phosphorus-31 nuclear magnetic resonance spectroscopy (abnormal MRS), consistent with myocardial ischemia. The prognostic implications of these findings are unknown. Methods and Results-Women referred for coronary angiography for suspected myocardial ischemia underwent MRS handgrip stress testing and follow-up evaluation. These included (1) nϭ60 with no CAD/normal MRS, (2) nϭ14 with no CAD/abnormal MRS, and (3) nϭ352 a reference group with CAD. Cardiovascular events were death, myocardial infarction, heart failure, stroke, other vascular events, and hospitalization for unstable angina. Cumulative freedom from events at 3 years was 87%, 57%, and 52% for women with no CAD/normal MRS, no CAD/abnormal MRS, and CAD, respectively (PϽ0.01). After adjusting for CAD and cardiac risk factors, a phosphocreatine-adenosine triphosphate ratio decrease of 1% increased the risk of a cardiovascular event by 4% (Pϭ0.02). The higher event rate in women with no CAD/abnormal MRS was primarily due to hospitalization for unstable angina, which is associated with repeat catheterization and higher healthcare costs. Conclusions-Among women without CAD, abnormal MRS consistent with myocardial ischemia predicted cardiovascular outcome, notably higher rates of anginal hospitalization, repeat catheterization, and greater treatment costs. Further evaluation into the underlying pathophysiology and possible treatment options for women with evidence of myocardial ischemia but without CAD is indicated.