Computer Aided Detection of Deep Inferior Epigastric Perforators in Computed Tomography Angiography scans
This work addresses the time-consuming and subjective manual annotation process for surgeons and radiologists in preoperative planning for breast reconstruction, representing an incremental improvement in medical imaging automation.
The authors tackled the problem of manually identifying deep inferior epigastric artery perforators in CT angiography scans for breast reconstruction by developing a semi-automatic method, which achieved an average error of 0.64 mm for subcutaneous paths and 0.50 mm for intramuscular paths compared to radiologist annotations.
The deep inferior epigastric artery perforator (DIEAP) flap is the most common free flap used for breast reconstruction after a mastectomy. It makes use of the skin and fat of the lower abdomen to build a new breast mound either at the same time of the mastectomy or in a second surgery. This operation requires preoperative imaging studies to evaluate the branches - the perforators - that irrigate the tissue that will be used to reconstruct the breast mound. These branches will support tissue viability after the microsurgical ligation of the inferior epigastric vessels to the receptor vessels in the thorax. Usually through a Computed Tomography Angiography (CTA), each perforator, diameter and direction is manually identified by the imaging team, who will subsequently draw a map for the identification of the best vascular support for the reconstruction. In the current work we propose a semi-automatic methodology that aims at reducing the time and subjectivity inherent to the manual annotation. In 21 CTAs from patients proposed for breast reconstruction with DIEAP flaps, the subcutaneous region of each perforator was extracted, by means of a tracking procedure, whereas the intramuscular portion was detected through a minimum cost approach. Both were subsequently compared with the radiologist manual annotation. Results showed that the semi-automatic procedure was able to correctly detect the course of the DIEAPs with a minimum error (average error of 0.64 mm and 0.50 mm regarding the extraction of subcutaneous and intramuscular paths, respectively). The objective methodology is a promising tool in the automatic detection of perforators in CTA and can contribute to spare human resources and reduce subjectivity in the aforementioned task.