Dynamic Infrared Thermography as an Alternative to CT Angiography (DIRT)

In deep inferior epigastric perforator flap (DIEP) breast reconstruction the blood supply to the DIEP flap is reestablished by anastomosing the perforator to the internal mammary vessels. The selected perforator is crucial for flap survival as it is the only source of blood supply to the flap. CTA allows for precise anatomical description of the origin of perforators, their intramuscular course and point of fascia penetration but expose the patient to ionizing radiation and an intravenous contrast medium.

DIRT is an imaging method that does not require ionizing radiation or contrast injection. The study evaluates if DIRT can be an alternative to CTA in perforator mapping. The study is performed in a hospital where DIRT and CTA have been established preoperative imaging methods that have been used for several years as routine examinations for all DIEP breast reconstruction patients.

25 patients scheduled for secondary breast reconstruction with a DIEP flap are included. Preoperatively, the lower abdomen is examined with hand-held Doppler, DIRT and CTA. Arterial Doppler sound locations are marked on the skin.

DIRT examination involves rewarming of the abdominal skin after a mild cold challenge. The locations of hot spots on DIRT are compared with the arterial Doppler sound locations. The rate and pattern of rewarming of the hot spots are analyzed. Multiplanar CT reconstructions are used to see if hot spots are related to perforators on CTA and intraoperative findings.

When intraoperative findings confirm that a useful perforator is located at the same localization as indicated with DIRT, this perforator is used for DIEP breast reconstruction. Postoperatively the surgical outcome and possible complications related to the selected perforator are evaluated.