Magnetic Resonance Imaging Compared With Computed Tomography for Segmentation-Based Cavity Volume Measurements in Gelatin Head Phantoms
Year: 2026
Type: article
Abstract: Gelatin-based phantoms are commonly used as soft-tissue simulants in wound ballistics research, yet MRI has not previously been applied for volumetric analysis in this setting. This study compared permanent cavity volumes measured on CT using soft and hard-kernel reconstructions (CTsoft, CThard) and MRI using 3D T1 and T2-weighted sequences (MRIT1, MRIT2) in 20 gelatin head phantoms shot with different ammunition types. Volumes were segmented manually and evaluated using correlation and Bland-Altman analyses. CT-MRI comparisons showed small mean biases (-1.07 to 3.03 cm 3 ) but wide 95% limits of agreement (LoA), ranging from -22.1 to 19.9 cm 3 depending on the modality pair, corresponding to potential deviations of approximately ±90% to 100% of a typical cavity volume. The closest agreement was observed for CThard-MRIT1 and CTsoft-MRIT2, while MRIT1-CTsoft exhibited the widest LoA. Metallic fragments did not impair segmentation, whereas air-filled regions produced susceptibility-related signal voids on MRI. Overall, CT and MRI both allow reliable visualization and measurement of permanent wound channels, but variability between modalities limits their interchangeability for precise volumetry in individual cases.
Institution: University of Zurich
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
OpenAlex ID: W7203741832