A semi-automated method using interpolation and optimisation for the 3D reconstruction of the spine from bi-planar radiography: a precision and accuracy study

Abstract

The 3D reconstruction of the spine in upright posture can be obtained by bi-planar radiographic methods, developed since the 1970s. The principle is to identify 4-25 anatomical landmarks per vertebrae and per images. This identification time is hardly manageable in clinical practice. A semi-automated method is used: 3D standard vertebral models are positioned along with a 3D curve (identified all the way through the vertebral bodies). The silhouettes of the models of C7 and L5 vertebrae are first adjusted and the positions of the other vertebrae are interpolated and optimised. The inter- and intra-operator variabilities and the errors between the semi-automated method and the manual identification of six anatomical landmarks per vertebra are evaluated on 20 pairs of X-ray images of subjects with different spinal deformities. The identification time for the semi-automated method is 5 min. For scolitic subjects, the precision is under 2.2 degrees and the accuracy is under 3.2 degrees for all lateral, sagittal and axial rotations.

Multi-view stereophotogrammetry for post-mastectomy breast reconstruction

“…The 3D stereophotogrammetry image system developed provided an alternative option for data collection and evaluation. It offered a convenient approach to measure the shapes of breasts, which had advantages over structured light projection [10,11], the laser scanning [4,12,13,14] in terms of the capturing time (less than 1ms), the photographic skin texture; and over 3D X-ray imaging [18,19,20] in terms of the radiation free nature. The photographic skin texture was important for the clinicians to identify the anatomical landmarks.…”

“…Threedimensional imaging techniques, such as structured light projections [10,11], 3D laser scanning [4,12,13,14] and 3D stereo photogrammetry imaging [2,3,15,16] have been applied on patients' breast measurement that enable a surgeon to obtain quantitative breast measurements [17]; to make volumetric calculations and to visually and quantitatively assess reconstructed breasts. 3D X-ray imaging [18] was applied on 3D reconstruction of spine [19,20], but it was radioactive and captured shapes only. 3D stereophotogrammetry imaging has advantages of fast image acquisition and photographic texture without radiation.…”

The assessment of the postoperative spinal alignment: MRI adds up on accuracy

“…However, this technique fails in the description of 3D orientation of the planes of regional curves [4]. Many techniques were developed to overcome this problem by the help of appropriate image analysis algorithms [5,6]. In these studies, however, mean thoracic kyphosis angles of the subjects under investigation were rather normal ([30°) and no metal hardware was implanted.…”

“…In these studies, however, mean thoracic kyphosis angles of the subjects under investigation were rather normal ([30°) and no metal hardware was implanted. Physical constraints of this biplanar radiographic technique, as there are the concealment of vertebrae by metal implants or the lungs cannot be solved by such algorithms [5]. In our study, regional analysis of thoracic kyphosis angles had to be done under realistic scoliosis circumstances (the mean thoracic kyphosis angle was around 20°).…”

Three-Dimensional Assessment of the Scoliosis

“…(Pomero 2004) The 3D representations can eventually be individually adjusted during handling according to the X-ray imaging for better reliability. (Blanchard 2008, Dumas 2008 Then, a customization process improves the visual appearance of the bony reconstruction. (Figure 18) A.…”