Tumor size on computed tomography scans: is one measurement enough?

Area of Science:

• Radiology
• Oncology
• Medical Imaging Analysis

Background:

• Bidimensional tumor measurements are commonly used as surrogates for actual tumor volume.
• Current clinical practice often relies on these indirect methods for assessing tumor burden.

Purpose of the Study:

• To evaluate the added benefit of bidimensional or tridimensional tumor measurements compared to unidimensional measurements.
• To determine the most accurate and efficient method for estimating tumor volume in colorectal hepatic metastases.

Main Methods:

• Analysis of 69 colorectal hepatic metastases across 19 computed tomography (CT) scans from 9 patients.
• Standard tumor volume determined using the "summation of areas" technique.
• Correlation of maximum axial dimension, product of greatest axial dimensions, and various geometric volume estimates (sphere, ellipsoid, cube) with standard volume.

Main Results:

• Maximum axial dimension and the product of greatest axial dimensions showed equal high correlation (r=0.93) with standard tumor volume.
• Geometric formulas for spheres and ellipsoids tended to underestimate tumor volume.
• The cube formula overestimated tumor volume compared to the standard method.

Conclusions:

• No significant added benefit exists in using bidimensional or tridimensional measurements over the maximum axial dimension for reporting tumor size.
• The maximum axial dimension provides a sufficiently accurate and simpler surrogate for tumor volume in this context.