title: Bidimensional unconstrained optimization approach to EMD: An algorithm revealing skin perfusion alterations in pseudoxanthoma elasticum patients.
abstract: OBJECTIVE
  Pseudoxanthoma elasticum (PXE) is an inherited and systemic metabolic disorder that affects the skin, leading among other things to a peau d'orange appearance. Unfortunately, PXE is still poorly understood and there is no existing therapy to treat the disease. Because the skin is the first organ to be affected in PXE, we propose herein a study of skin microvascular perfusion. By means of this analysis, our goal is to increase knowledge of PXE.
  
  
  METHODS
  For this purpose, microvascular data from patients suffering from PXE and from healthy control subjects were recorded using the laser speckle contrast imaging (LSCI) modality. These data were processed using the recent 2D version of the unconstrained optimization approach to empirical mode decomposition (UOA-EMD). Our work therefore corresponds to the first time this algorithm has been applied to biomedical data.
  
  
  RESULTS
  Our study shows that the 2D-UOA-EMD is able to reveal spatial patterns on local textures of LSCI data. Moreover, these spatial patterns differ between PXE patients and control subjects. Quantification measure of these spatial patterns reveals statistical significant differences between PXE and control subjects, in the neck (p=0.0004) and in the back (p=0.0052).
  
  
  CONCLUSIONS
  For the first time, alterations in microvascular perfusion in PXE patients have been revealed. Our findings open new avenues for our understanding of pathophysiologic skin changes in PXE.
authors.affiliation: University of Angers, LARIS - Laboratoire Angevin de Recherche en Ingénierie des Systèmes, 62 avenue Notre-Dame du Lac, 49000 Angers, France. Electronic address: anne.humeau@univ-angers.fr.
authors.forename: Anne
authors.initials: A
authors.lastname: Humeau-Heurtier
authors.affiliation: Laboratorio de Señales y Dinámicas no Lineales,Facultad de Ingeniería, Univ. Nacional de Entre Ríos, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
authors.forename: Marcelo A
authors.initials: MA
authors.lastname: Colominas
authors.affiliation: Laboratorio de Señales y Dinámicas no Lineales,Facultad de Ingeniería, Univ. Nacional de Entre Ríos, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina; Centro de Investigación y Transferencia de Entre Ríos (CITER), Argentina.
authors.forename: Gastón
authors.initials: G
authors.lastname: Schlotthauer
authors.affiliation: University of Angers, Angers Hospital, Department of Dermatology, UMR CNRS 6214-INSERM 1083, Angers, France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Etienne
authors.affiliation: University of Angers, Angers Hospital, Department of Dermatology, UMR CNRS 6214-INSERM 1083, Angers, France.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Martin
authors.affiliation: University of Angers, Angers Hospital, Laboratoire de Physiologie et d'Explorations Vasculaires, UMR CNRS 6214-INSERM 1083, Angers, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Abraham
mesh_terms: D000465:Algorithms; D016022:Case-Control Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D011561:Pseudoxanthoma Elasticum / Q000503:physiopathology*; D012867:Skin / Q000503:physiopathology*
keywords: Convex optimization; Data-driven method; Empirical mode decomposition; Laser speckle contrast imaging; Pseudoxanthoma elasticum; Time-frequency