Improvements of the Tada formula in estimating the intracerebral hemorrhage volume based on computed tomography

BACKGROUND: The Tada formula has been used widely for assessing intracerebral hemorrhage (ICH) volume. However, it is only suitable for calculating regular and small volume hematomas. Therefore, we attempted to improve the formula to increase its accuracy and maintain its efficiency. METHODS: Computed tomography (CT) data of 15 balls of different shapes filled with predetermined volumes of water were collected to verify the high accuracy of FireVoxel in measuring the volume. CT data from 329 patients with ICH from two different hospitals grouped by hematoma shape and volume were retrospectively reviewed. The distinctly shaped ICH volumes of 245 patients from one of the hospitals were estimated using FireVoxel and the Tada formula grouped by the hematoma shape and volume. Taking the hematoma volumes measured by FireVoxel as the reference standard, the accuracy and reliability of the Tada formula were evaluated. Polynomial fitting was employed to determine the associations of the values calculated between the Tada formula and FireVoxel. Then, a corrected Tada formula (C-Tada formula) was produced, and the limits of agreement between the C-Tada formula and Tada formula were analyzed with Bland-Altman analysis. The C-Tada formula was validated by the CT data of 84 patients from another hospital. RESULTS: The volume measured by FireVoxel can be set as the reference standard. The ICH volume calculated by the Tada formula was significantly greater than that calculated by FireVoxel for different shapes and volumes. The percentage deviation between the volumes calculated by FireVoxel and the Tada formula was also statistically significant and influenced by ICH shape and volume. The limits of agreement between the C-Tada formula and FireVoxel were tighter than those between the Tada formula and FireVoxel. The percentage deviation of the C-Tada formula calculation from the FireVoxel estimate was greatly reduced relative to that for the Tada formula for each group. CONCLUSIONS: The C-Tada formula is more clinically valuable than the Tada formula, given its sufficient efficiency and greater accuracy and reliability in ICH volume calculation.