Spherical cap model of epidural hematomas

Epidural hematomas (EDHs), which have a characteristic biconvex shape, are a type of post-traumatic intracranial mass. EDHs and other types of intracranial hematomas are often diagnosed with computed tomography (CT). Based on our half sphere model of the supratentorial brain parenchyma, we modeled the geometry of EDHs with two spherical caps. Applying the relationship between the sphere radius, spherical cap height, and base circle radius, we derived formulas for the shape of an EDH, relating its largest diameter and location to the other two diameters. We also estimated EDH volumes using the spherical cap volume and conventional ABC formulas. We then constructed a lookup table accordingly. Our model was verified using EDH diameter measurements in 14 CT image sets from previously reported patients. With our model, the number of parameters needed for EDH volume estimation was reduced from three to one, accelerating clinical decision-making for critically injured patients. © 2022, CC BY.