Advances Using 3-D Computer Technology
Applied use of Computed Tomography (CT) in Preoperative Planning
The use of advanced three dimensional ( 3D ) computer technology in the analysis, virtual surgical planning, 3D modeling, and custom printing of implants have enhanced treatment of complex congenital and acquired craniofacial deformities.
Modern 3D technology allows the surgeon to better analyze complex craniofacial deformities, precisely plan surgical correction with a computer simulation of results, customize osteotomies, plan distractions, and print custom 3D implants, as needed. The use of advanced 3D computer technology can be applied safely and potentially improve aesthetic and functional outcomes after complex craniofacial reconstruction.
Application of Computed Tomography Generated 3-Dimensional Modeling, and Postoperative Outcome
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What is a Computed Tomography (CT) Scan?
In many ways, CT scanning works very much like other x-ray examinations. Different body parts absorb the x-rays in varying degrees. It is this crucial difference in absorption that allows the body parts to be distinguished from one another on an x-ray film or CT electronic image.
In a conventional x-ray exam, a small amount of radiation is aimed at and passes through the part of the body being examined, recording an image on a special electronic image recording plate. Bones appear white on the x-ray; soft tissue, such as organs like the heart or liver, shows up in shades of gray, and air appears black.
With CT scanning, numerous x-ray beams and a set of electronic x-ray detectors rotate around you, measuring the amount of radiation being absorbed throughout your body. Sometimes, the examination table will move during the scan, so that the x-ray beam follows a spiral path. A special computer program processes this large volume of data to create two-dimensional cross-sectional images of your body, which are then displayed on a monitor. CT imaging is sometimes compared to looking into a loaf of bread by cutting the loaf into thin slices. When the image slices are reassembled by computer software, the result is a very detailed multidimensional view of the body's interior.
Refinements in detector technology allow nearly all CT scanners to obtain multiple slices in a single rotation. These scanners, called multislice CT or multidetector CT, allow thinner slices to be obtained in a shorter period of time, resulting in more detail and additional view capabilities.
Modern CT scanners are so fast that they can scan through large sections of the body in just a few seconds, and even faster in small children. Such speed is beneficial for all patients but especially children, the elderly and critically ill, all of whom may have difficulty in remaining still, even for the brief time necessary to obtain images.
For children, the CT scanner technique will be adjusted to their size and the area of interest to reduce the radiation dose.
For some CT exams, a contrast material is used to enhance visibility in the area of the body being studied.
Converting the 3-Dimensional CT Scan to a Preoperative Model.
Following a Ct Scan, you will be given a disc, USB drive, or other forms of data containing a device with your results which should be brought to our office.
The information will also be made available to us here at Cleft and Craniofacial Center Utah by the imaging center, though this can take a few days. Once received, we view the results in our propitiatory 3-dimensional imaging programs. From here we can pan, rotate, zoom in or out, and even slice or section the model in virtual space, accurately assessing the operative corrections that will need to be made. Finally, we convert the file into a suitable format for the 3-Dimensional printer and create a physical model of the syndrome or trauma. From here this model is used for the final stage of preoperative planning. In most cases, you will see it in surgery, as it provides a valuable asset to the procedure.
Step 1 will be the Ct Scan, which will create a series of images of the treatment area.
Step 2 will be the organization of all the raw data images in the series into the 3-Dimensional software.
Step 4 is to convert the virtual image into a working 3-dimensional model. Printing from the virtual image file.
Step 3 will be to use the collection of the "z-stack" or image series, to create a virtual 3-dimensional representation of the treatment area.
Step 5 is the physical assessment of the printed model in the preoperative analysis.
Importantly, this process can be done in a matter of a few days, or as quick as 24 hours, depending on the time frame required. Furthermore, these models can also be generated from Magnetic Resonance Imaging (MRI) or CT of most any bone, soft tissue, vascular system, or organ in the body.
With continued advancement in the speed at which the CT and MRI scanners can collect data, the introduction of a cloud-based sharing system for these larger image files, the ever-increasing resolution of these images, and the materials with which can be printed, the future of this technology in medical applications are limitless.