1. One or more computer-readable media comprising computer-executable instructions for performing a method comprising: receiving a digital representation of an anatomical structure; performing a trial segmentation of the digital representation, wherein performing the trial segmentation comprises segmenting the digital representation into at least trial air pockets and a plurality of trial fluid pockets, producing a trial representation, wherein segmenting comprises locating an air-fluid boundary between a trial air pocket and an adjacent trial fluid pocket; for at least a subset of the trial fluid pockets, determining at least one per-fluid-pocket tailored threshold for each trial fluid pocket in the subset, wherein determining the at least one per-fluid-pocket tailored threshold comprises determining separate thresholds for respective trial fluid pockets in the subset, whereby a first trial fluid pocket out of the subset is associated with a first per-fluid-pocket tailored threshold and a second trial fluid pocket out of the subset is associated with a second per-fluid-pocket tailored threshold and the first per-fluid-pocket tailored threshold is different from the second per-fluid-pocket tailored threshold; and resegmenting at least a portion of the trial representation, wherein the re-segmenting segments at least a portion of the anatomical structure comprising the first trial fluid pocket via the first per-fluid-pocket tailored threshold and segments at least a portion of the anatomical structure comprising the second trial fluid pocket via the second per-fluid-pocket tailored threshold; wherein determining a per-fluid-pocket tailored threshold for a trial fluid pocket comprises choosing voxels or pixels near the air-fluid boundary of the trial fluid pocket and using attenuation values of the chosen voxels or pixels near the air-fluid boundary of the trial fluid pocket and wherein determining the per-fluid-pocket tailored threshold for the trial fluid pocket does not use all possible voxels or pixels in the trial fluid pocket; wherein the method further comprises: determining a location of at least one trial fluid pocket; storing the location of the trial fluid pocket to determine if the trial fluid pocket comprises separate fluid pockets; wherein the resegmenting comprises determining an enclosing boundary of at least a portion of the anatomical structure, wherein the resegmenting further comprises resegmenting at least one trial fluid pocket using the at least one per-fluid-pocket tailored threshold to produce at least one tailored fluid pocket; organizing the at least one tailored fluid pocket and trial air pockets into a hierarchical pocket tree wherein tailored fluid pockets touching a same trial air pocket are at a same level in a hierarchy of the hierarchical pocket tree; analyzing tailored fluid pockets to determine whether a given tailored fluid pocket belongs to a leaked region; and responsive to determining that the given tailored fluid pocket belongs to a leaked region, deleting pockets below the given tailored fluid pocket in the hierarchical pocket tree.