ABSTRACT
BACKGROUND: Head circumference (HC) correlates with brain growth and development. However, radiologists typically use their visual impressions to evaluate head dimensions, which is a purely subjective assessment. OBJECTIVE: The first objective of this paper was to analyze whether it is possible to obtain HC measurements by CT and MRI cross-sectional volumetric imaging using parameters similar to the tape measurement method, which is considered the gold standard. The second objective was to determine the most accurate method for characterizing head size: visual impression or imaging measurement. MATERIALS AND METHODS: Children who underwent HC measurement by tape and with volumetric imaging exams were selected from the Paulo Niemeyer State Brain Institute, Brazil. Two radiologists classified the children's heads using their visual impressions and by direct measurement on imaging. We used anatomical parameters similar to the tape measurement method and appropriate head growth charts and compared the absolute values obtained. RESULTS: The concordance between tape and imaging ranged 52.3-72.7% for visual impression (kappa 0.27-0.55), ≥ 95.5% for CT and ≥ 93.1% for MRI (kappa ≥ 0.92 and ≥ 0.88, respectively). Intraclass correlation coefficients ≥ 0.997 and ≥ 0.996, absolute technical error measurements of 0.20-0.31 cm and 0.24-0.29 cm, and relative technical error measurements of 0.49-0.73% and 0.58-0.70% were evidenced in the intra- and inter-rater evaluations, respectively. The means between the methods were not significantly different (P > 0.05), with high values of Pearson correlation coefficient (≥ 0.99) and Lin concordance correlation coefficient (≥ 0.99). CONCLUSION: Head circumference values obtained by cross-sectional volumetric imaging are similar to those obtained using the tape measurement method (gold standard), with high repeatability and reproducibility. Head size characterization by visual impression is less accurate than head circumference measurement by imaging and plotting the values obtained on World Health Organization normative charts.
