Morphometry and Laser Scanner Imaging: A Revolution in Anatomy

Abstract

Anatomy is a visual science, even if the visual quality of anatomy can be declined in different ways, as we will show. Anatomy holds its own main feature in the etymology of the name itself: it is through cutting (ανά, anà) by lancet (τέμνω, tèmno) that preparations are yet prepared. This operation is aimed to make evident and well visible anatomical structures. Vesalius is the first modern anatomist and his main heuristic principle consists in the equivalence between seeing and knowing. The possibility of analyzing fresh anatomical preparations is made short by the unavoidable decomposition processes of the cadaver. Due to this reason beautiful and precious tables have always been drawn, painted and printed. We remember the ones by the Fisiocritic Paolo Mascagni, whose double centenary of death is celebrated this year. Watercolor tables are yet much realized and used. However they are bi-dimensional schematizations and, even if well done, they remain far from reality. Photography allows to fix the image of anatomical preparations with high fidelity of particulars. However these images are static. The graphic synthesis allows to realize four-dimensional human virtual models. They can be rotated according to the three spatial axes and, thanks to this, they can be observed from every point of view. Due to the fact that these are schematizations, they are very far from reality. For this reason CT three-dimensional reconstruction, that rebuilds anatomy in three dimensions, allows to obtain results with very superior quality and fidelity. However these reproductions lack color and real light. The gap between the iconographic representation and the existing thing is and will always be not fully eliminable. However our use of laser scanner technology allows to reduce this gap to minimal levels, with a quick and easy acquisition process. Laser scanner generates a cloud of points of the examined object. Each point is identified through exact coordinates. Besides, the photos of the same object can be over-placed to the cloud. The result is a virtual model that reconstructs the real object, highly corresponding as in morphology and as in colors. This virtual model allows us to interact and we can rotate it, watch at it from every perspective and especially we can measure it. The scanner we have used allowed us to reach an accuracy of ±25 μm. The anatomical preparation is literally “immortalized”, up to under-millimetric details, where the naked eye is ineffective. The so obtained image allows to re-observe and to measure the object forever. We can imagine a lot of very innovative, if not revolutionary applications. We realized our four-dimensional models aiming to attach them to this project. These scanning are of two skulls and of a heart. They are the concrete proof of the possibility of obtaining surprising results in many areas, from normal anatomy to pathological anatomy, from legal medicine to biology. This way of obtaining anatomical images is marking a turning point from a taxonomic, serial and verbal conception of Anatomy to a visual, spatial and mathematical one. Instead of lists of nominal labels we have now coordinates and quantitative/structural references. This makes Anatomy more treatable through digital methods. The visual approach has far origins: since XIII Century, when real (not formal) Renaissance of figurative arts begins, and during following ages, visual paradigms gain more and more importance in human knowledge. Once more we are dwarves on the shoulders of giants. Besides, detecting morphology by laser scanner pushes us to re-configure the relationship between nomothetic and ideographic approach in building scientific models.

Dynamic three‐dimensional virtual environment to improve learning of anatomical structures

“…Three-dimensional scanning generates a cloud of points of the examined object (Gelati & Tanga, 2015). Each point is identified through exact coordinates.…”

“…Besides, the photos of the same object can be layered to the cloud. The result is a virtual model that reconstructs the real object, highly corresponding as in morphology and as in colors (Gelati & Tanga, 2015). Three-dimensional scanning technologies have been investigated as to their potential use in medicine: analysis of facial anatomy (Gibelli et al, 2018) and knee cartilage (Chang et al, 2010), breast surgery (Sakakibara et al, 2008) and plastic surgery guidance (Chae et al, 2016).…”

“…Four‐dimensional (4D) technology adds the time variable and provides a real‐life experience. A 4D model is a 3D model which can be rotated and observed from every perspective (Gelati & Tanga, 2015; Suzuki et al, 2016; Carr et al, 2019). In case of ultrasound, 4D ultrasound is a 3D with the time aspect—live video of the record.…”