chapter  10
12 Pages

Digital Thermographic Photography for Preoperative Perforator Mapping

In planning ap reconstruction, it is crucial to be able to identify a suitable perforator. It has been well recognised that preoperative localisation of the involved perforating arteries in the planning of musculocutaneous or fasciocutaneous aps can lead to a higher survival rate of the whole skin island. With the introduction of freestyle reconstruction aps comes a need for a safe and reliable method of perforator mapping. Wei et al. described freestyle aps when a ap is raised after a perforator was identied in an unfamiliar region; ap harvest can still be done, by surgically exploring the region for vessels of suitable size.1 This had led to an increase in the number of aps available. The need for an accurate and simple imaging modality has become increasingly important. Several imaging technologies have been developed and utilised by reconstructive surgeons in helping to identify this crucial information prior to ap design. Doppler ultrasound yields a low sensitivity and is operator dependent for both identifying and interpretation of results. Cutaneous perforators can be mapped by magnetic resonance imaging (MRI), computed tomographic angiography (CTA), and digital subtraction angiography (DSA), each of which is not without morbidity and can be associated with radiation exposure, risk of contrast reactions and extravasation,

10.1 Overview ............................................................................................................................... 129 10.2 History of Thermography ..................................................................................................... 130

10.2.1 Early Thermography Development ........................................................................... 130 10.2.2 History of IR Imaging in Medicine .......................................................................... 130

10.3 Physiology of Heat Transport in the Skin ............................................................................. 131 10.4 Use of DIRT in Assessing and Mapping Perforators in Preoperative Flap Reconstruction...... 131 10.5 Cold Challenge ..................................................................................................................... 133 10.6 Comparison of DIRT to Other Modalities in Preoperative Perforator

Mapping for Flap Planning ................................................................................................... 134 10.6.1 DIRT versus Doppler Probe ..................................................................................... 134 10.6.2 DIRT versus CTA ..................................................................................................... 134

10.7 IR Thermography: Procedure and Protocol ......................................................................... 137 10.7.1 Pre-Examination Preparation ................................................................................... 137 10.7.2 Procedure .................................................................................................................. 137 10.7.3 Reporting .................................................................................................................. 138

10.8 Summary .............................................................................................................................. 138 References ...................................................................................................................................... 139

and/or nephrotoxicity. These modalities, while providing accurate and precise information on the details of vascular anatomy, can be time-consuming and expensive. The need for non-invasive, inexpensive, sensitive, accurate bedside devices with minimal or no adverse effects has pushed radiologists and reconstructive surgeons into seeking alternative imaging technologies. Several papers in the literature have analysed the use of digital infrared (IR) thermography in preoperative ap reconstruction planning.