Comparison of diameter and perimeter methods for tumor volume calculation

Area of Science:

• Oncology
• Medical Imaging
• Radiology

Background:

• Lesion volume is a critical endpoint in oncology clinical trials.
• Accurate volume estimation is essential for assessing treatment response.

Purpose of the Study:

• To compare the accuracy and variability of the diameter method versus a computer-assisted perimeter method for estimating lesion volume.
• To determine the impact of different volume estimation techniques on therapy response assessment.

Main Methods:

• Magnetic resonance imaging (MRI) studies of 219 glioblastoma multiforme patients were analyzed.
• Lesion volumes were estimated using both the diameter and perimeter methods, excluding cystic areas.
• Inter- and intrareader variability was assessed, along with mock response analysis for serial studies.

Main Results:

• The perimeter method demonstrated significantly reduced intrareader (1.76 mL vs 7.38 mL) and interreader (2.51 mL vs 9.07 mL) variability compared to the diameter method (P < .001).
• Classification differences occurred in 26.1% of serial non-cystic cases when comparing the two methods.

Conclusions:

• The computer-assisted perimeter method offers more accurate detection of volume changes due to reduced measurement variability.
• The observed differences between methods are substantial enough to influence the grading of therapy response in clinical trials.