A method is disclosed for determining a branching point within a hollow organ in image data representing the spatial structure thereof. In at least one embodiment, the method includes setting a start point within the hollow organ; determining at least one local threshold which corresponds to the presence of a wall of the hollow organ; carrying out a region growing method using the threshold; analyzing the connectivity of a number of outer growth layers; and localizing a branching on the basis of the connectivity analysis. Moreover, at least one embodiment of the invention relates to a correspondingly designed branching determination unit.