Improved 3-D-echocardiographic endocardial border delineation using the contrast agent FS069 (Optison) transesophageal studies in a porcine model.

3-D echocardiography has the potential for quantitative assessment of regional wall motion. However, the 3-D procedures used to date do not provide the same spatial and temporal resolution as 2-D echocardiography, which results in problems with border delineation of the endocardium. There are, as yet, few studies testing if the use of contrast agent can improve endocardial definition in the 3-D data set. FS069 (Optison) was used for the first time for this purpose in the present study. A total of 12 mechanically-ventilated pigs were examined by transesophageal 3-D echocardiography, 1. using fundamental imaging and 2. following left-atrial injection of FS069 (Optison). The left ventricle was analyzed using an 18-segment model. Score with the value 0 (not visible), 1 (moderately visible) and 2 (well defined) were used to rate endocardial definition. All segments were assessed both end-diastolic and end-systolic. Various LV regions were examined by grouping segments (anterior/lateral/inferior and basal/mid-ventricular/apical). Using the contrast agent, the proportion of nonvisible segments fell diastolic from 40 (18.5%) to 15 (6.9%), and systolic from 26 (12.0%) to 11 (5.1%). The proportion of well defined segments increased diastolic from 62 (28.7%) to 108 (50%) and systolic from 73 (33.8%) to 123 (56.9%). The mean visibility score increased diastolic from 1.10 +/- 0.68 to 1.43 +/- 0.62 (p < 0.001), systolic from 1.22 +/- 0.64 to 1.52 +/- 0.59 (p < 0.001). The benefit was greatest in regions where the visibility score was lowest without contrast: in the area of the lateral wall and systolic near the apex. In conclusion, the use of FS069 (Optison) results in significantly better endocardial delineation in the 3-D data set. This could be important in future for the 3-D echocardiographic assessment of regional wall motion.

Dynamic changes of atrial septal defect area: new insights by three-dimensional volume-rendered echocardiography with high temporal resolution.

AIMS: The purpose of this study was: (i) to record dynamic changes in the area of atrial septal defects (ASD) during a cardiac cycle, and (ii) to investigate factors which influence ASD dynamics. Implementation of new software modifications allowed the frame rate to be doubled, as compared to usual techniques. METHODS AND RESULTS: Twenty patients were examined using transoesophageal three-dimensional (3D) echocardiography. In 10 patients the 3D dataset was recorded with a frame rate of 25Hz, in another 10 patients with a frame rate of 50Hz. The ASD area was planimetried for each picture and the changes analysed over time. The ASD area showed dynamic changes during the cardiac cycle with an end-systolic maximum and end-diastolic minimum. The influence of the various phases of the cardiac cycle on area changes could be differentiated especially at higher temporal resolution. The relative change in ASD area showed no significant relationship to Q(p)/Q(s)ratio, mean ASD size or heart rate. By contrast, there was a slight inverse correlation to age (r=-0.t45,P <0.05). CONCLUSION: Transoesophageal 3D volume-rendered echocardiography permits quantitative recording of ASD dynamics. The ASD area changes are influenced especially by the various phases of the cardiac cycle.

High dietary manganese lowers heart magnesium in pigs fed a low-magnesium diet.

Young pigs were fed a diet moderately high or low in manganese (Mn) (0.95 +/- 0.10 mmol Mn/kg, n = 8 or 0.040 +/- 0.003 mmol Mn/kg, n = 6) and deficient in magnesium (Mg) (4.1 mmol Mg/kg) for 5 wk. All eight pigs consuming the high Mn diet died following convulsive seizures, whereas only two of six died in the group fed low Mn. In an attempt to determine the cause of death, a subsequent study examined the interactive effect of deficient dietary Mg and Mn on the tissue distribution of Mg and Mn. Pigs were individually fed, for 5 wk, diets that contained: 4.1 mmol Mg/kg and 36.0 micromol Mn/kg, 4.1 mmol Mg/kg and 0.91 mmol Mn/kg, 4.1 mmol Mg/kg and 0.91 mmol Mn/kg with added ultratrace minerals, or 41.1 mmol Mg/kg and 0. 91 mmol Mn/kg, and ultratrace minerals. Liver and skeletal muscle Mn concentrations were significantly elevated by increased dietary Mn. Increased dietary Mn did not affect heart Mn, but heart Mg concentrations were significantly depressed by high, as compared to low, dietary Mn (38.7 +/- 3.3 vs. 32.7 +/- 2.6 mmol Mg/kg). These data suggest high dietary Mn may exacerbate Mg deficiency in heart muscle and thus may be a complicating factor in the deaths observed in Mg-deficient pigs.

Soft tissue composition of pigs measured with dual x-ray absorptiometry: comparison with chemical analyses and effects of carcass thicknesses.

Evidence of the validity and accuracy of dual x-ray absorptiometry (DXA) to measure in vivo body composition is limited. We compared DXA estimates made in prone and side positions with measurements of chemical composition of 20 pigs (10 barrows and 10 gilts) weighing 52-113 kg. DXA yielded similar estimates of body composition in prone and side positions. DXA estimates of body composition were significantly correlated with reference compositional values (r2 = 0.927-0.998). No significant differences were found for determinations of body weight, fat mass (FM), fat free mass (FFM), bone-free, and fat-free mass (BFFFM) between DXA and chemical determinations. DXA significantly underpredicted percent fat (% fat); it underestimated FM (20%, P > 0.05), and overestimated FFM and BFFFM (6 and 9%, respectively, P > 0.05). Differences between individual determinations of FM and % fat by chemical analyses and DXA were significantly correlated with mean values. No significant correlations were found between the differences for weight, FM, % fat, FFM and BFFFM and measurements of carcass breadth (19-28 cm) and width (15-25 cm). Total errors in determination of DXA body composition variables were similar with body thicknesses less than and greater than 24 cm. These findings indicate that DXA is a valid and accurate method for determination of soft tissue composition. Initial problems with DXA determinations of % fat apparently have been reconciled partially with revisions in soft tissue analytic software.

Myxoma of the mitral valve: diagnosis by 2-dimensional and 3-dimensional echocardiography.

In this report we describe a 39-year-old patient who had left-sided hemiparesis. In search of a source of embolism, we performed transthoracic echocardiography, which did not show any abnormalities. Transesophageal echocardiography revealed a small tumor of the posterior mitral leaflet. Three-dimensional transesophageal echocardiography was subsequently performed and demonstrated more accurate information about the size, the morphology, and the attachment point of the tumor. Furthermore, the reconstruction provided excellent spatial visualization of the pathomorphology of the mitral valve and was a useful addition for optimal preoperative diagnostic management. The tumor was excised, and histologic examination confirmed the myxomatous character of the tumor. Mitral valve myxomas are rare. This is the first case reported of a mitral valve myxoma being visualized by 3D echocardiography.

Effect of biliary ligation on manganese accumulation in rat brain.

Neurologic and radiologic disorders have been reported to occur in miners inhaling manganese (Mn)-laden dust and in humans receiving long-term parenteral nutrition. These abnormalities have been attributed to Mn intoxication because of elevated serum Mn concentrations. Because the liver, by way of the bile, is the major route of Mn excretion, it is possible that anything that decreases biliary excretion could increase accumulation of Mn in the brain. The purpose of this study was to determine whether biliary ligation would increase Mn accumulation in the brain of rats that were exposed to deficient or adequate amounts of dietary manganese. The first experiment had a 2 x 3 factorial design, two levels of Mn (0 or 45 microg/g diet) and three surgical treatments (control, sham, or bile-ligation). Animals were sacrificed 10 d after being fed 54Mn. In experiment 2, animals that had a sham operation or bile-ligation were sacrificed at 8 time points after being injected intraportally with 54Mn complexed to albumin. The biliary-ligated animals had a significantly (p < 0.001) smaller percentage of the 54Mn in their brains (when expressed as a percentage of whole animal 54Mn) than the sham-operated animals. Mn deficiency had a similar effect. However, we did observe an increased accumulation of the radioisotope in the brain over time. Therefore, in short-term studies, biliary-ligated rats do not appear to be a good model for Mn accumulation in the brains of people with cholestatic liver disease.