Novel technique for three-dimensional visualisation and quantification of deformable, moving soft-tissue body parts

Background Three-dimensional (3D) imaging of delicate, moving soft-tissue b ody parts is very difficult. Our understanding of the muscles that control lip movements is based largely on histological and cadaveric studies, which provide scant information about dynamic morphology. Our aim was to develop an innovative scanning technique for the imaging and reconstruction of dyn amic orofacial morphology by use of 3D and four-dimensional (4D, ie, 3D plu s time) ultrasonography. Methods Four volunteers (including one patient) underwent ultrasonography w ith 3D/4D imaging systems. To avoid deformation of the delicate orofacial s tructures, a water bath with an acoustic window was devised. The orofacial part was immersed in the bath throughout scanning, and a timer was used to synchronise lip movements with the 4D scan. Findings 4D views showed the functional differences in superficial and deep muscle groups of the lips, and clearly showed the changes occurring with m ovement of the lips and mouth. In the patient, a pathological layer and its extension corresponding to surface malformation were clearly identified. Interpretation We have developed a prototype device that has made possible 3D and 40 examination of orofacial anatomy and function. With further refin ement of the device and improvement in 4D acquisition timing, this techniqu e may offer a new way of dynamically imaging and quantifying many soft-tiss ue parts in 3D without deforming structure or disturbing function.