Accuracy of 3D radiological skull measurements: reoriented sections and geometric correction versus caliper reference

Three-dimensional radiological imaging is important for disease diagnosis and surgical planning, yet its accuracy in anatomical length measurements remains challenging. Standard sections calculations often underestimate actual dimensions due to orthographic projection distortions. This study evaluates the accuracy of reoriented section measurements and formula-based calculations compared to standard sections and reference caliper verifications.

A plastic human skull model was used for standardized length measurements. Five cranial dimensions (Ma-G, Ma-N, Ma-Rh, Ma-Ns, Ma-Me) were measured using a digital caliper as the reference. A computed tomography scan with a slice thickness of 0.625 mm was performed, and measurements were obtained from standard sections (sagittal, transverse, coronal), reoriented section, and formula-based calculations. Measurement agreement was assessed using Bland-Altman analysis and repeated-measures ANOVA.

Reoriented sections values (e.g., Ma-G: 13.18 ± 0.52 cm, Ma-N: 12.59 ± 0.24 cm) and formula-based calculations (e.g., Ma-G: 13.15 ± 0.26 cm, Ma-N: 12.61 ± 0.80 cm) closely matched caliper measurements (p > 0.05). In contrast, standard section parameters were significantly lower across all parameters (e.g., Ma-G sagittal: 12.03 ± 0.48 cm, p = 0.0005; coronal: 7.39 ± 0.56 cm, p < 0.0001). Bland-Altman analysis confirmed high agreement for reoriented sections and formula-based methods, whereas standard sections showed significant deviations (p < 0.05).

Reoriented sections findings and formula-based calculations offer accuracy comparable to caliper measurements, while standard sections results consistently underestimate the reference caliper values. These findings highlight the limitations of standard-section approaches and suggest that alternative methods may improve anatomical assessment in 3D imaging. These techniques may help reduce measurement-related discrepancies in settings requiring precise anatomical assessment. Such precision may be relevant in fields such as orthodontics, orthopedics, and implant planning, where accurate anatomical measurements are important.