title: Functional-thermoregulatory model for the differential diagnosis of psoriatic arthritis.
abstract: BACKGROUND
  Psoriasis arthritis (PsA) is a chronic inflammatory arthritis of joints of uncertain pathogenesis. PsA may lead to severe disabilities even in the absence of any clinical symptom. Therefore, PsA diagnosis in its early stages is critical.
  
  
  METHODS
  This study uses Control System theory to model finger skin thermoregulatory processes overlying the hand joint in response to an isometric exercise. The proposed model is based on a homeostatic negative feedback loop characterized by four distinct parameters that describe how the control mechanisms are activated and maintained. Thermal infrared imaging was used to record a total of 280 temperature curves of 14 finger joints for each of 11 PsA patients and 9 healthy controls.
  
  
  CONCLUSIONS
  PsA patients presented delayed and prolonged re-warming processes characterized by the undershoot onset after the end of the isometric exercise followed by a faster temperature increase. Region classification on the basis of the model parameters demonstrated that the interphalageal joint region of thumb better discriminates between patients and controls, providing 100% true-positive discrimination for PsA affected regions and 88.89% of correct classification of healthy regions. Even proved over a limited number of subjects, the proposed method may provide useful hints for early differential diagnosis in the IR assessment of PsA disease.
authors.affiliation: Department of Neuroscience, Imaging and Clinical Sciences, University "G, d'Annunzio", Via dei Vestini, 31, 66013 Chieti, Italy. mustafa.enas@unich.it.
authors.forename: Enas
authors.initials: E
authors.lastname: Ismail
authors.forename: Alessandra
authors.initials: A
authors.lastname: Capo
authors.forename: Paolo
authors.initials: P
authors.lastname: Amerio
authors.forename: Arcangelo
authors.initials: A
authors.lastname: Merla
mesh_terms: D015535:Arthritis, Psoriatic / Q000175:diagnosis* / Q000503:physiopathology*; D001833:Body Temperature Regulation; D016022:Case-Control Studies; D003937:Diagnosis, Differential; D015444:Exercise; D005260:Female; D005385:Fingers; D050823:Hand Joints / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D012867:Skin / Q000503:physiopathology