Rationale and Objectives
Tumor volume is one of the most important factors in evaluating the response to treatment
of patients with cancer. The objective of this study was to compare computed tomographic
(CT) volume calculation using a semiautomated circumscribing tracing tool (manual
circumscription [MC]) to prolate ellipsoid volume calculation (PEVC; bidimensional
measurement multiplied by coronal long axis) and determine which was more accurate
and consistent.
Materials and Methods
The study included six patients with nine neoplasms, six phantoms, and two radiologists.
The neoplasms and phantoms of varying sizes and shapes were imaged using multidetector
CT scanners, with slice thicknesses ranging from 0.5 to 3 mm. Measurements were performed
using a TeraRecon 3D workstation. Each lesion and phantom was manually circumscribed,
and its three dimensions were measured. The measurements were repeated 2 weeks later.
Results
MC of the phantoms deviated from their true volumes by an average of 3.0 ± 1%, whereas
PEVC deviated by 10.1 ± 3.99%. MC interobserver readings varied by 1.2 ± 0.6% and
PEVC by 4.8 ± 3.3%. MC intraobserver readings varied by 1.95 ± 1.75% and PEVC by 2.5
± 1.55%. Patient tumor volume predicted by MC and PEVC varied greatly; MC interobserver
readings differed by 3.3 ± 2.1% and PEVC by 20.1 ± 10.6%. MC intraobserver readings
varied by 2.5 ± 1.9% and PEVC by 5.5 ± 3.2%. Variability was greater for complex shapes
than for simple shapes. Bidimensional analysis demonstrated an interobserver difference
of 12.1 ± 8.7% and an intraobserver difference of 5.05 ± 3.3%. These results demonstrate
large interobserver and intraobserver variability. Variability was greater for complex
shapes than for simple shapes.
Conclusion
MC of neoplasms provided more accurate and consistent volume predictions than PEVC.
More complicated shapes demonstrated the superiority of MC over PEVC.
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Article Info
Publication History
Accepted:
August 7,
2008
Received:
May 13,
2008
Identification
Copyright
© 2009 AUR. Published by Elsevier Inc. All rights reserved.
