Intraoperative monitoring of blood perfusion in port wine stains by laser Doppler imaging during vascular targeted photodynamic therapy: A preliminary study

Objective: The objective of this study was to monitor blood perfusion dynamics of port wine stains (PWS) during vascular targeted photodynamic therapy (V-PDT) with laser Doppler imaging (LDI). Methods: The PWS lesions of 30 facial PWS patients received V-PDT, while the normal skins on the forearm of 5 healthy subjects were treated as light-only controls for comparison. Furthermore, two different PWS lesions in the same individual from each of 3 PWS patients successively received laser irradiation only and V-PDT, respectively. LDI was used to monitor intraoperative blood perfusion dynamics. Results: During V-PDT, the blood perfusion (278 ± 96 PU) in PWS lesions for 31 of 33 PWS patients significantly increased after the initiation of V-PDT treatment, then reached a peak (638 ± 105 PU) within 10 min, followed by a slow decrease to a relatively lower level (515 ± 100 PU). Furthermore, the time for reaching peak and the subsequent magnitude of decrease in blood perfusion varied with different patients. For light-only controls, an initial perfusion peak at 3 min followed by a nadir and a secondary increase were found not only in normal skin, but also in PWS lesions. Conclusion: The preliminary results showed that the LDI permits non-invasive monitoring blood perfusion changes of PWS lesions during V-PDT. There was a clear trend in blood perfusion responses during V-PDT and laser irradiation. The blood perfusion changes during treatment were due to V-PDT effects as well as local temperature increase induced by laser irradiation.