title: Automatic non-rigid temporal alignment of intravascular ultrasound sequences: method and quantitative validation.
abstract: Clinical studies on atherosclerosis regression/progression performed by intravascular ultrasound analysis would benefit from accurate alignment of sequences of the same patient before and after clinical interventions and at follow-up. In this article, a methodology for automatic alignment of intravascular ultrasound sequences based on the dynamic time warping technique is proposed. The non-rigid alignment is adapted to the specific task by applying it to multidimensional signals describing the morphologic content of the vessel. Moreover, dynamic time warping is embedded into a framework comprising a strategy to address partial overlapping between acquisitions and a term that regularizes non-physiologic temporal compression/expansion of the sequences. Extensive validation is performed on both synthetic and in vivo data. The proposed method reaches alignment errors of approximately 0.43 mm for pairs of sequences acquired during the same intervention phase and 0.77 mm for pairs of sequences acquired at successive intervention stages.
authors.affiliation: Department of Applied Mathematics and Analysis, University of Barcelona, Barcelona, Spain. malberti@cvc.uab.es
authors.forename: Marina
authors.initials: M
authors.lastname: Alberti
authors.forename: Simone
authors.initials: S
authors.lastname: Balocco
authors.forename: Xavier
authors.initials: X
authors.lastname: Carrillo
authors.forename: Josepa
authors.initials: J
authors.lastname: Mauri
authors.forename: Petia
authors.initials: P
authors.lastname: Radeva
mesh_terms: D000465:Algorithms; D019160:Endosonography / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods*
keywords: Dynamic time warping; Intravascular ultrasound; Non-rigid alignment; Partial overlapping strategy; Sequence matching