Application of different noninvasive diagnostic techniques used in HMME-PDT in the treatment of port wine stains

Hematoporphyrin monomethyl ether photodynamic therapy (HMME-PDT) is an effective method for treating port wine stains (PWS). However, methods to evaluate the treatment of HMME-PDT for PWS effectively and objectively are lacking.This study aimed to describe the different noninvasive diagnostic techniques used in the evaluation of treatment response to HMME-PDT for PWS.Thirty-one lesions of 22 patients with PWS were treated with HMME-PDT. Four noninvasive diagnostic techniques including VISIA-CR™ system, dermoscopy, high-frequency ultrasound (HFUS), and laser speckle contrast imaging (LSCI) were used to obtain standard radiographic data on skin color, skin thickness, blood vessel morphology, blood vessel distribution, and blood perfusion from lesions and surrounding normal skin before and after HMME-PDT.The standard image pattern of VISIA-CR™ system showed color change in the lesions of PWS after HMME-PDT. RBX red image of VISIA-CR™ system showed that erythema was highly aggregated even in invisible lesions at baseline but decreased after HMME-PDT. The erythema index reduced value d was related to the efficacy rating (γ = 0.631, P < 0.05). Dermoscopy showed that the number of spot-like and irregular linear vessels increased, which was correlated with the increase in clinical classification. After HMME-PDT, vascular rupture was observed by dermoscopy. The response rate of lesions with vascular rupture was 100.00% (20/20). Moreover, the response rate of lesions without vascular rupture was 63.64% (7/11). Vascular rupture sign was correlated with better efficacy (P < 0.05). HFUS showed that the dermis of PWS thickened and was arranged loosely with scattered linear hypoechoic signal. After HMME-PDT, the dermal layer of the lesions became thinner with a decreased linear hypoechoic signal. The response rate of the lesions with linear hypoechoic signal was 76.92% (10/13), and that without linear hypoechoic signal was 94.44% (17/18). The lesions without linear hypoechoic signal in the dermis showed better efficacy (P < 0.05). In some lesions, LSCI showed high blood perfusion signal in PWS lesions and blood perfusion reduction after HMME-PDT.VISIA-CR™ system can be used to observe not only visible but also invisible lesions of PWS. Moreover, lesions fading after HMME-PDT can be described objectively by VISIA-CR™ system. Dermoscopy played an important role in the clinical classification of PWS, including assessing vascular injury after HMME-PDT, guiding the adjustment of therapeutic dose, and selecting the end point of treatment. Both HFUS and LSCI can be used to assist treatment response evaluation of HMME-PDT.