Room: AAPM ePoster Library
Purpose: Preclinical imaging is commonly used in longitudinal studies to test the efficacy of novel treatments. The purpose of this study is to investigate the accuracy of tumor volume and growth determination using MR imaging/contour delineation and caliper measurements.
Methods: Mice with flank tumors (n = 31 tumors) with a large range in size (18 – 152 mm³) were grouped into four treatment groups and monitored using caliper measurements and weekly MR images on a GE Signa 1.5T MR scanner. Tumor volume was measured using three methods. The first and second methods (Caliper Linear Measurement and MR Linear Measurement methods) measured two perpendicular dimensions of the tumors using the calipers or the MR images, and calculated the volume using a common formula found in the literature. The third method (MR Contouring method) involved contouring the tumors on each slice of the MR image using a contouring GUI. Tumor volume and tumor growth (the ratio of tumor volume 2 weeks after treatment to that near the day of treatment) were compared using these methods.
Results: Tumor volume measured by the MR Linear Measurement and Caliper methods were usually lesser than that measured using the MR Contouring method, although the differences between the measurements using MR methods were more closely clustered together (s=26%) compared to the differences between the Caliper and MR Contouring methods (s=66%). The average tumor growth measurements obtained using the two MR methods statistically agreed with one another, although results disagreed by as much as 18.7%.
Conclusion: The study indicates that the measurement method significantly affects the accuracy of tumor volume as well as tumor growth determination, and that contouring on each slice of the MR scans cannot in general be substituted by methods that measure two dimensions of the tumor.
Not Applicable / None Entered.