## Abstract The results of the direct analysis of the ABX spin system present in two symmetrical diphosphonates containing a single vinylic ^13^C nucleus are presented. This allows a comparison to be made with the two‐dimensional methods used by Beckmann __et al.__ Significant differences are found
Evaluation of gallbladder volume and emptying with a novel three-dimensional ultrasound system: Comparison with the sum-of-cylinders and the ellipsoid methods
✍ Scribed by Pauletzki, Jürgen; Sackmann, Michael; Holl, Joseph; Paumgartner, Gustav
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 765 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0091-2751
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✦ Synopsis
To overcome the geometrical limitations of current methods to calculate gallbladder volume from two-dimensional sonographic images, we evaluated the accuracy and precision of a novel three-dimensional ultrasound system (3D). In vitro accuracy of 3D volumetry (10 mL to 55 mL) was 98.1 * 7.1% (mean * SD) with a mean difference of 0.7 mL between the measured and the true volume ( p < 0.003). Compared with the sum-of-cylinders (SC) and the ellipsoid (EL) methods, 3D was characterized by a significantly smaller systematic bias and closer limits of agreement with the true volume. The variation coefficient was smallest with 3D (2.4%, p < 0.02) and largest with EL (4.2%). In vivo, gallbladder volumes were on average 1.4 mL (9%) smaller with 3D than with SC ( p < 0.0001) and 2.4 mL (14%) larger with EL than with SC ( p < 0.0001). 3D ultrasonography accurately measures gallbladder volume and emptying.
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