title: Robust Spatio-Temporal Registration of 4D Cardiac Ultrasound Sequences.
abstract: Registration of multiple 3D ultrasound sectors in order to provide an extended field of view is important for the appreciation of larger anatomical structures at high spatial and temporal resolution. In this paper, we present a method for fully automatic spatio-temporal registration between two partially overlapping 3D ultrasound sequences. The temporal alignment is solved by aligning the normalized cross correlation-over-time curves of the sequences. For the spatial alignment, corresponding 3D Scale Invariant Feature Transform (SIFT) features are extracted from all frames of both sequences independently of the temporal alignment. A rigid transform is then calculated by least squares minimization in combination with random sample consensus. The method is applied to 16 echocardiographic sequences of the left and right ventricles and evaluated against manually annotated temporal events and spatial anatomical landmarks. The mean distances between manually identified landmarks in the left and right ventricles after automatic registration were (mean ± SD) 4.3 ± 1.2 mm compared to a reference error of 2.8 ± 0.6 mm with manual registration. For the temporal alignment, the absolute errors in valvular event times were 14.4 ± 11.6 ms for Aortic Valve (AV) opening, 18.6 ± 16.0 ms for AV closing, and 34.6 ± 26.4 ms for mitral valve opening, compared to a mean inter-frame time of 29 ms.
authors: GE Vingmed Ultrasound, Horten, Norway ; University of Oslo, Oslo, Norway ; Center for Cardiological Innovation, Oslo, Norway.
authors: Jørn
authors: J
authors: Bersvendsen
authors: École de Technologie Supérieure, Montreal, Canada.
authors: Matthew
authors: M
authors: Toews
authors: GE Vingmed Ultrasound, Horten, Norway ; University of Leuven, Leuven, Belgium.
authors: Adriyana
authors: A
authors: Danudibroto
authors: Brigham and Women's Hospital, Harvard Medical School, Boston, USA.
authors: William M
authors: WM
authors: Wells
authors: Oslo University Hospital, Oslo, Norway.
authors: Stig
authors: S
authors: Urheim
authors: Brigham and Women's Hospital, Harvard Medical School, Boston, USA.
authors: Raúl San José
authors: RS
authors: Estépar
authors: GE Vingmed Ultrasound, Horten, Norway ; University of Oslo, Oslo, Norway ; Center for Cardiological Innovation, Oslo, Norway.
authors: Eigil
authors: E
authors: Samset