Journal of Medical Physics
 Home | Search | Ahead of print | Current Issue | Archives | Instructions | Subscription | Login  The official journal of AMPI, IOMP and AFOMP      
 Users online: 2810  Home  EMail this page Print this page Decrease font size Default font size Increase font size 
Year : 2010  |  Volume : 35  |  Issue : 3  |  Page : 174-180

Longitudinal volume analysis from computed tomography: Reproducibility using adrenal glands as surrogate tumors

Department of Radiology, University of California Davis Medical Center, Ellison Ambulatory Care Center, 4860 Y Street Suite 3100, Sacramento, CA, USA

Correspondence Address:
Nicolas D Prionas
University of California Davis Medical Center, Department of Radiology 4860 Y Street, Room 0505 Sacramento
Login to access the Email id

Source of Support: Grant from the National Institutes of Health (R01 EB002138) and National Center for Research for Medical Research (UL1 RR024146), Conflict of Interest: None

DOI: 10.4103/0971-6203.62130

Rights and Permissions

This study aims to determine the precision (reproducibility) of volume assessment in routine clinical computed tomography (CT) using adrenal glands as surrogate tumors. Seven patients at our institution were identified retrospectively as having received numerous abdominal CT scans (average 13.1, range 5 to 20). The adrenal glands were used as surrogate tumors, assuming no actual volume change. Left and right adrenal gland volumes were assessed by hand segmentation for each patient scan. Over 1240 regions of interest were outlined in total. The reproducibility, expressed as the coefficient of variation (COV), was used to characterize measurement precision. The average volumes were 5.9 and 4.5 cm 3 for the left and right adrenal gland, respectively, with COVs of 17.8% and 18.9%, respectively. Using one patient's data (20 scans) as an example surrogate for a spherical tumor, it was calculated that a 13% change in volume (4.2% change in diameter) could be determined with statistical significance at P=0.05. For this case, cursor positioning error in linear measurement of object size, by even 1 pixel on the CT image, corresponded to a significant change in volume (P=0.05). The precision of volume determination was dependent on total volume. Precision improved with increasing object size (r 2 =0.367). Given the small dimensions of the adrenal glands, the ~18% COV is likely to be a high estimate compared to larger tumors. Modern CT scanners working with thinner sections (i.e. <1 mm) are likely to produce better measurement precision. The use of volume measurement to quantify changing tumor size is supported as a more precise metric than linear measurement.

Print this article     Email this article
 Next article
 Previous article
 Table of Contents

 Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
 Citation Manager
 Access Statistics
 Reader Comments
 Email Alert *
 Add to My List *
 * Requires registration (Free)

 Article Access Statistics
    PDF Downloaded114    
    Comments [Add]    
    Cited by others 2    

Recommend this journal