Hello the Biomedical 3D Printing community, it's Devarsh Vyas here writing after a really long time!
This time i'd like to share my personal experience and challenges faced with respect to medical 3D Printing from the MRI data. This can be a knowledge sharing and a debatable topic and I am looking forward to hear and know what other experts here think of this as well with utmost respect.
In the Just recently concluded RSNA conference at Chicago had a wave of technology advancements like AI and 3D Printing in radiology. Apart from that the shift of radiologists using more and more MR studies for investigations and the advancements with the MRI technology have forced radiologists and radiology centers (Private or Hospitals) to rely heavily on MRI studies.
We are seeing medical 3D Printing becoming mainstream and gaining traction and excitement in the entire medical fraternity, for designers who use the dicom to 3D softwares, whether opensource or FDA approved software know that designing from CT is fairly automated because of the segmentation based on the CT hounsifield units however seldom we see the community discuss designing from MRI, Automation of segmentation from MRI data, Protocols for MRI scan for 3D Printing, Segmentation of soft tissues or organs from MRI data or working on an MRI scan for accurate 3D modeling.
Currently designing from MRI is feasible, but implementation is challenging and time consuming. We should also note reading a MRI scan is a lot different than reading a CT scan, MRI requires high level of anatomical knowledge and expertise to be able to read, differentiate and understand the ROI to be 3D Printed. MRI shows a lot more detailed data which maybe unwanted in the model that we design. Although few MRI studies like the contrast MRI of the brain, Heart and MRI angiograms can be automatically segmented but scans like MRI of the spine or MRI of the liver, Kidney or MRI of knee for example would involve a lot of efforts, expertise and manual work to be done in order to reconstruct and 3D Print it just like how the surgeon would want it.
Another challenge MRI 3D printing faces is the scan protocols, In CT the demand of high quality thin slices are met quite easily but in MRI if we go for protocols for T1 & T2 weighted isotropic data with equal matrix size and less than 1mm cuts, it would increase the scan time drastically which the patient has to bear in the gantry and the efficiency of the radiology department or center is affected.
There is a lot of excitement to create 3D printed anatomical models from the ultrasound data as well and a lot of research is already being carried out in that direction, What i strongly believe is the community also need advancements in terms of MRI segmentation for 3D printing. MRI, in particular, holds great potential for 3D printing, given its excellent tissue characterization and lack of ionizing radiation but model accuracy, manual efforts in segmentation, scan protocols and expertise in reading and understanding the data for engineers have come up as a challenge the biomedical 3D printing community needs to address.
These are all my personal views and experiences I've had with 3D Printing from MRI data. I'm open to and welcome any tips, discussions and knowledge sharing from all the other members, experts or enthusiasts who read this.
Thank you very much!
3D printing technologies have opened up the capabilities for customization in a wide variety of applications in the medical field. Using bio-compatible and drug-contact materials, medical devices can be produced that are perfectly suited for a particular individual. Another trend enabled by 3D printing is mass customization, in that multiple individualized items can be produced simultaneously, saving time and energy while improving manufacturing efficiency.
3D printers are used to manufacture a variety of medical devices, including those with complex geometry or features that match a patient’s unique anatomy.
Some devices are printed from a standard design to make multiple identical copies of the same device. Other devices, called patient-matched or patient-specific devices, are created from a specific patient’s imaging data.
Commercially available 3D printed medical devices include:
Instrumentation (e.g., guides to assist with proper surgical placement of a device)
Implants (e.g., cranial plates or hip joints)
External prostheses (e.g., hands)
In summary, the 3D Printing medical device market looks exciting and promising, Various Reports and surveys suggest the unexpected growth and demand for 3D Printing in medical device industry and it is expected to blossom more but a number of existing application areas for 3D printing in healthcare sector require specialized materials that meet rigid and stringent bio-compatibility standards, Future 3D printing applications for the medical device field will certainly emerge with the development of suitable additional materials for diagnostic and therapeutic use that meet CE and FDA guidelines.
Cutting down costs for 3D prints is the number one concern for many Doctors and Patients. In order to achieve this, we need to understand how costs for 3D prints are calculated. Probably the most important variable is the amount of material that is needed for printing your medical object. So all we need to do is to make sure to use as little material as possible.
Here are our some top tips for more successful 3D printing. They're short and to the point, and if you follow them, you'll find your models will stand straight and look beautiful.
Create a hollow 3D model & 3D print with Escape Holes if needed.
A hollow model means that the interior of your object will not be solid. Solid designs are not necessarily a problem – they will be stronger and harder to break (depending on the material), but they will also be more expensive as more 3D printing material will be used.With a hollow model the interior of your print will be empty (in theory). However, since our printers print layer by layer, 3D printing material can get trapped in the interior of your model. If you would like to avoid this, you can add ‘escape holes’ to your design. Material that is not used for building your 3D print can then be removed.
However, creating a 3D model with an empty interior can be a bit tricky, you need to know how to hollow your model in the 3D modeling software you’re using, you need to define a wall thickness that is strong enough for your model not to break, and it probably makes sense to add so-called ‘escape holes’ to your model
Why do I need escape holes? As already pointed out, our 3D prints are created layer by layer. With a hollow interior, this means that 3D printing materials can get trapped inside the object. A hollow model full of trapped powder is in danger of deforming. Escape holes are recommended for getting ‘trapped’ 3D printing material out of your 3D print. We typically use pressurized air for cleaning the excess powder off.
How do I design escape holes? Again, the exact procedure depends on your software but the idea is often the same: create a cylinder at the bottom of your model and extrude or subtract from its wall
If you plan on printing out a figure as one solid piece, you'll want to consider placing supports at overhang areas. Some slicing/preference software will do this automatically.
The Infill for FDM 3D Printing
The Slicing softwares lets you adjust the infill percentage and infill type to print your model in FDM. Choosing the correct percentage and type of infill depending on how strong you want your model to be can reduce the volume of your model making it cheaper.
Know your materials
Learn the tolerances of the various materials used. It's better to err on the larger side, because you can always sand or trim down the piece afterwards.
Happy 3D Printing!!
Role of 3D Printing in Scoliosis Correction Surgery
Scoliosis is a medical condition in which a person's spine has a sideways curve. The curve is usually "S" or "C" shaped. Scoliosis occurs most often during the growth spurt just before puberty. In some cases, the person suffering from the disease can be left unable to stand up straight, to walk, or even, in the most severe cases, to breathe properly. In the most severe scoliosis cases, however, surgery is the only option. Back surgery is never a minor procedure, and scoliosis surgery is especially tricky, as it requires screws or wires to be placed throughout multiple vertebrae and then connected to stabilize the back
Fig: Scoliosis Example
3D printing has done quite a bit to make scoliosis treatment less agonizing for even severe cases. Here is an over view of how 3D Printing is a complete package in diagnosing, treatment and rehabilitation for scoliosis patients.
· 3D Printed Patient Specific Models for Pre-Surgical Planning
Recognition of complex anatomical structures in scoliosis can sometimes be difficult to attain from simple 2D radio-graphic views. 3D models of patients’ anatomy facilitate this task and allow doctors to familiarize themselves with a specific patient. This approach proved to reduce drastically OT time, especially in complex scoliosis cases. Getting to know patients’ anatomy before entering an OT allows to plan the exact approach, helps to predict bottlenecks and even test procedures beforehand.
Fig: Scoliosis Pre operative model to be 3D Printed.
No standard models nor 2D images can replace 3D printing as the first do not represent the specific case in debate and the latter may hide important details, especially in the spatial relationship between structures. 3D prints may be as well used by a doctor to explain to a patient his or her condition. Offering a patient possibility to understand his case and procedure may be reassuring and produce better treatment outcome by reducing stress and insecurity.
· 3D Printed Patient Specific Surgical Guides in Scoliosis
Another recent advancement in the 3D Printing applications for spine surgeries are the 3D-printed Patient specific pedicle screw guides, realized in a customized manner with 3D printers. Their aim is to orient and guide in a precise fashion the placement of the screw in the pedicle. In complex scoliosis cases and revision surgeries it is very difficult to find the pedicle and the entry point for the screw guides. 3D Printing addresses this challenge and proves to be accurate, this level of accuracy is absolutely useful for patients with scoliosis, whose common anatomical landmarks can be in an abnormal position or might be not easily recognizable.
Fig: Patient specific 3D printed guides.
The guides involve surgical planning and software assisting surgical placement of pedicle screws designed specifically for a patients' unique anatomy. It is essentially a 3D printed surgical tool that fits the patient's unique anatomy. The 3D Printed surgical guides are printed in SLS and are bio compatible to be used on the patient's body. It is easy to see how these new customizable tools can greatly improve Scoliosis Surgery outcomes. These enhanced tools promise to improve patient satisfaction and physician performance, using the tailor-made patient-specific guides for the spine vertebrae utilizing proprietary CT scan algorithms and sophisticated 3-D medical printing technology.
· 3D Printed Patient Specific Braces for Scoliosis
Moderately severe scoliosis (30-45 degrees) in a child who is still growing may require bracing. The main goal of 3D Printed scoliosis brace is to combine fashion, design, and technology to create a brace far more appealing to patients, and, as a result, far more effective medically.
Fig: 3D Printed scoliosis Brace.
The 3D Printed patient specific brace represents a meaningful innovation in scoliosis treatment. Using advanced 3D scanning and printing technology, the Scoliosis Brace addresses the most common objections to traditional bracing. The 3D Printed braces are usually printed in SLS (Selective Laser Sintering) for its strength durability and aesthetic features along with bio compatibility. This is what happens when Design innovation meets Medical Innovation.
To conclude the use of three dimensional printing in scoliosis surgeries has a wide range of applications from pre operative models to patient specific guides and orthotics proving to be a complete package in aiding Scoliosis surgeries and treatment.