Volume measurement of the XXXX : a discussion and comparison of the alternatives to manual segmentation.

@entity439 @entity438
OBJECTIVE: Several modalities are available for volumetric measurement of the @entity438 . We discuss the challenges involved in manual segmentation, and analyze the application of alternative methods using automatic segmentation and geometric formulae in measurement of @entity439 volumes and coil packing density. METHODS: The volumes and morphology of 38 @entity439 treated with endovascular coiling at a single center were measured using three-dimensional rotational angiography (3DRA) reconstruction software using automatic segmentation. @entity439 volumes were also calculated from their height, width, depth, size of neck, and assumed shape in 3DRA images using simple geometric formulae. The @entity439 volumes were dichotomized as "small" or "large" using the median volume of the studied population (54 mm(3)) measured by automatic segmentation as the cut-off value for further statistical analysis. RESULTS: A greater proportion of @entity439 were categorized as being "small" when geometric formulae were applied. The median @entity439 volumes obtained were 54.5 mm(3) by 3DRA software, and 30.6 mm(3) using mathematical equations. An underestimation of @entity439 volume with a resultant overestimation in the calculated coil packing density (p = 0.002) was observed. CONCLUSION: Caution must be exercised in the application of simple geometric formulae in the management of @entity438 as volumes may potentially be underestimated and packing densities falsely elevated. Future research should focus on validation of automatic segmentation in volumetric measurement and improving its accuracy to enhance its application in clinical practice.
