Background: There is limited understanding of anatomy of perforator angiosomes, or “perforasomes,” of the deep inferior epigastric artery (DIEA). A perforasome is defined as the territory perfused by a single perforator vessel of a named artery, such as the DIEA. Given the clinical significance of this anatomical concept in microsurgical breast reconstruction, this study is a quantitative investigation of DIEA perforasome characteristics and patterns associated with perforasome size, perforator caliber, location and branching, using computed tomographic (CT) angiography. Methods: Twenty abdominal arterial-phase CT angiograms were analyzed in 3 dimensions using software (Horos). DIEA perforasomes were mapped, yielding data on 40 medial-row and 40 lateral-row perforasomes. Perforator branch extents and number were measured using 3-dimensional multi-planar reconstruction, and perforator caliber on axial slices. Results: Perforasomes exhibited eccentric branching distributions in horizontal and vertical axes, that is, a majority of perforators were not centrally located within their perforasomes. Lateral-row perforasomes displayed greater horizontal eccentricity than medial-row. There was a positive correlation between perforator caliber and perforasome size. Medial-row perforators had more branches and larger caliber than lateral-row. Conclusions: This is the first article to quantify relationships between perforators and their territories of supply in vivo, augmenting current understanding of perforasome theory. DIEA perforasomes can be readily visualized and mapped with CT angiography, which may enable effective preoperative flap planning in DIEA perforator flap breast reconstruction. Future investigation may highlight the importance of this information in improving surgical outcomes, including flap survival and fat necrosis reduction, through careful, perforasome-based flap design.