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Found 158 results

  1. lupixus

    cap

    Version 1.0.0

    1 download

    rmn cap, MRI, with contrast, .stl, dicom, frontal, temporal, foramina, paranasal, sinuses, clinoud, apophysis, external, auditory, conduct, ear, auditory, conduct, ear, petrous, ridge, lower, turbinates, nasal, septum, maxilla, mandible, upper, teeth, tooth, canine, incisor, molar, premolar, orbit, sinus, venous, sigmoid, straight, cerebellum, vermis, lobules, hemispheres, pterygioid, muscles, neck, foramen, magnum, cervical, spine, atlas, axis, carotid, artery, media, anterior, posterior, brain, striates, basal, ganglia, cistern, 3d, model, printable,

    Free

  2. geebiss

    hhj

    Version 1.0.0

    1 download

    kkj Frontal sinus, Frontal bone, Falx cerebri, Orbital gyri, Straight gyrus, Superior temporal gyrus, Middle temporal gyrus, Optic chiasm, Amygdaloid body, Pituitary stalk, Lateral ventricle temporal horn), Dorsum sellae, Hippocampus, Pentagon of basal cisterns, Inferior temporal gyrus, Parahippocampal gyrus, Tentorium cerebelli, Pons Sigmoid sinus, Cerebellar peduncle (middle), Fourth ventricle, Dentate nucleus, vermis of cerebellum (superior part), Temporal bone, Confluence of the sinuses, Cerebellar hemisphere, Transverse sinus, Occipital bone, thyroid, gland, carotid, yugular, maxilla, maxillary, sinus, hard, palate, nasopharynx, nasal septum, lower turbinates, mandible, MRI, without, contrast,

    Free

  3. I've recently been asked about how to 3D print white matter tracts from brain MRI. I know it can be done because I wrote a blog article about this a few years back, but I don't know, technically, how to do it. Does anybody have experience with converting MRI DTI data to 3D print? I know several members of the community would be interested in the answer. Thanks, Dr. Mike
  4. lrvolle

    Test

    Version 1.0.0

    2 downloads

    first test, 3d, model, .stl, bone, foot, Distal phalanx, Middle phalanx, Proximal phalanx, Distal interphalangeal joint, Proximal interphalangeal joint, Metatarsophalangeal joint, Sesamoids, Metatarsals, Tarsometatarsal joint (Lisfranc’s joint), Medial cuneiform, Middle cuneiform, Lateral cuneiform, Intertarsal joint, Base of the fifth metatarsal, Navicular, Cuboid, Talocalcaneonavicular joint, Transverse tarsal joint (Chopart’s joint), calcaneus, navicular, and cuboid, printable, lower, limb, foot, fibula, tibia, ankle, interosseus muscle, peroneal, plantar, MRI, without, contrast,

    Free

  5. robtek91

    123

    Version 1.0.0

    5 downloads

    MRI, without contrast, .stl, 3d, model, printable, brain, cerebellum, circular sulcus of insula, temporal, parietal, occipital, frontal, corpus, callosum, hypophysis, sinus, paranasal, veins, cerebral, insular arteries, cisterns, tongue, orbit eyeball, maxillofacial, muscles, facial, thalamus, grey matter, white matter, neck, cervical, spine, atlas, axis,lordosis, mastoid, process, inner, ear, cerebral, trunk, vermis, hemisphere, without

    Free

  6. Justin H

    Spine JH 2

    Version 1.0.0

    3 downloads

    Thoracic spine Esophagus, Vertebra prominens C7, Thyroid gland. Interspinalis cervicis muscle, Trachea, Supraspinous ligament, Sternohyoid muscle, Thoracic vertebral body, Interspinous ligament, Sternum (manubrium), Spinous process. Ascending aorta, Thoracic spinal cord, Anterior longitudinal ligament. Inferior vertebral endplate T6, Intervertebral disk T9/T10 (anulusfibrosus), Ligamentum flavum, Superior vertebral endplate T7, Epidural fatty tissue (retrospinal fat), Conus medullaris, Intervertebral disk T9/T10 (nucleus pulposus), Cauda equina, Filum terminale, Descending aorta, MRI, without, contrast, .stl, 3d, model, printable,

    Free

  7. Justin H

    Spine JH 1

    Version 1.0.0

    0 downloads

    Thoracic spine Esophagus, Vertebra prominens C7, Thyroid gland. Interspinalis cervicis muscle, Trachea, Supraspinous ligament, Sternohyoid muscle, Thoracic vertebral body, Interspinous ligament, Sternum (manubrium), Spinous process. Ascending aorta, Thoracic spinal cord, Anterior longitudinal ligament. Inferior vertebral endplate T6, Intervertebral disk T9/T10 (anulusfibrosus), Ligamentum flavum, Superior vertebral endplate T7, Epidural fatty tissue (retrospinal fat), Conus medullaris, Intervertebral disk T9/T10 (nucleus pulposus), Cauda equina, Filum terminale, Descending aorta, MRI, without, contrast, .stl, 3d, model, printable,

    Free

  8. Justin H

    Spine JH 3

    Version 1.0.0

    1 download

    Thoracic spine Esophagus, Vertebra prominens C7, Thyroid gland. Interspinalis cervicis muscle, Trachea, Supraspinous ligament, Sternohyoid muscle, Thoracic vertebral body, Interspinous ligament, Sternum (manubrium), Spinous process. Ascending aorta, Thoracic spinal cord, Anterior longitudinal ligament. Inferior vertebral endplate T6, Intervertebral disk T9/T10 (anulus fibrosus), Ligamentum flavum, Superior vertebral endplate T7, Epidural fatty tissue (retrospinal fat), Conus medullaris, Intervertebral disk T9/T10 (nucleus pulposus), Cauda equina, Filum terminale, Descending aorta, MRI, without, contrast, .stl, 3d, model, printable,

    Free

  9. Fabiola_Araos

    prueba fabi

    Version 1.0.0

    2 downloads

    prueba, head, neck, axial, stl, dicom, 3dmodel, print, brain, lobules, Frontal sinus, Frontal bone, Falx cerebri, Orbital gyri, Straight gyrus, Anterior cerebral artery, Optic chiasm, Amygdaloid body, Pituitary stalk, Lateral ventricle (temporal horn), Dorsum sellae, Hippocampus, Pentagon of basal cisterns, Inferior temporal gyrus, Parahippocampal gyrus, Tentorium cerebelli, Basilar artery and basal sulcus, Pons Sigmoid sinus, Cerebellar peduncle (middle), Fourth ventricle, Dentate nucleus, vermis of cerebellum (superior part), Temporal bone, Confluence of the sinuses, Cerebellar hemisphere, Transverse sinus, Occipital bone, carotid, yugular, maxilla, maxillary, sinus, hard, palate, nasopharynx, nasal septum, lower turbinates, mandible, MRI, T1, without, contrast,

    Free

  10. tkjeldsen

    THK_body_2

    Version 1.0.0

    0 downloads

    some more of my body, head, neck, axial, stl, dicom, 3dmodel, print, brain, lobules, Frontal sinus, Frontal bone, Falx cerebri, Orbital gyri, Straight gyrus, Anterior cerebral artery, Anterior communicating artery, Internal carotid artery, Superior temporal gyrus, Middle temporal gyrus, Middle cerebral artery, Posterior communicating artery, Optic chiasm, Amygdaloid body, Pituitary stalk, Lateral ventricle (temporal horn), Dorsum sellae, Hippocampus, Pentagon of basal cisterns, Inferior temporal gyrus, Posterior cerebral artery, Parahippocampal gyrus, Tentorium cerebelli, Basilar artery and basal sulcus, Pons Sigmoid sinus, Cerebellar peduncle (middle), Fourth ventricle, Dentate nucleus, vermis of cerebellum (superior part), Temporal bone, Confluence of the sinuses, Cerebellar hemisphere, Transverse sinus, Occipital bone, thyroid, gland, carotid, yugular, maxilla, maxillary, sinus, hard, palate, nasopharynx, nasal septum, lower turbinates, mandible, MRI, T1, without, contrast,

    Free

  11. ADARSH KUMAR SHARMA

    Knee

    Version 1.0.0

    0 downloads

    about knee, knee replacement, Vastus medialis muscle, Vastus lateralis muscle, Femur (shaft) Iliotibial tract, Medial collateral ligament, Lateral femoral condyle, Medial femoral condyle, Lateral meniscus (anterior horn), Lateral tibial condyle, Medial meniscus (anterior horn), Medial tibial condyle, Peroneus (fibularis) longus muscle, Extensor digitorum longus muscle, Tibia (shaft), Tibialis anterior muscle, knee, pes anserinus (superficial), Semimembranosus muscle (tibial attachment deep pesanserinus), Extensor digitorum longus muscle, Popliteus muscle, patella , MRI, t1, without, contrast, 3D, model, .stl, printable, meniscus,

    Free

  12. tkjeldsen

    THK_body

    Version 1.0.0

    0 downloads

    my body , MRI, without, contrast, Body of vertebra, Superior vertebral end plate, Inferior vertebral end plate, Intervertebral disk space, Facet joint, Superior articular process, Inferior articular process, Transverse process, Spinous process, Pedicle, Sacroiliac joint, Sacrum, Sacral foramina, 3d, model, .stl, printable, bone, dicom, ribs, muscles, paravertebral, lumbar, foramina, coccyx, psoas, muscle, T1

    Free

  13. Wally Gillespie

    6 sag T3

    Version 1.0.0

    3 downloads

    test, Superior lateral genicular artery, Vastus medialis muscle, Vastus lateralis muscle, Femur (shaft) Iliotibial tract, Medial collateral ligament, Lateral femoral condyle, Medial femoral condyle, Lateral meniscus (anterior horn), Lateral tibial condyle, Medial meniscus (anterior horn), Medial tibial condyle, Peroneus (fibularis) longus muscle, Extensor digitorum longus muscle, Tibia (shaft), Tibialis anterior muscle, knee, pes anserinus (superficial), Semimembranosus muscle (tibial attachment deep pesanserinus), Extensor digitorum longus muscle, Popliteus muscle, patella , MRI, t1, without, contrast, 3D, model, .stl, printable, meniscus, Anterior Cruciate Ligament Rupture, knee, lower, limb

    Free

  14. levipoonypoon

    ct scan

    Version 1.0.0

    1 download

    ct scan, MRI, brain, thalamus, brain, cerebellum, parietal, occipital, frontal, cerebral, brainstem, orbit, maxillary, sinus, pterygoid, process, muscles, without, contrast, .stl, printable,

    Free

  15. ADARSH KUMAR SHARMA

    SAG

    Version 1.0.0

    1 download

    About sag, Vastus medialis muscle, Vastus lateralis muscle, Femur (shaft), Iliotibial tract, Medial collateral ligament, Lateral femoral condyle, Medial femoral condyle, Lateral meniscus (anterior horn), Lateral tibial condyle, Medial meniscus (anterior horn), Medial tibial condyle, Peroneus (fibularis) longus muscle, Extensor digitorum longus muscle, Tibia (shaft), Tibialis anterior muscle, knee, pes anserinus (superficial), Semimembranosus muscle (tibial attachment deep pesanserinus), Extensor digitorum longus muscle, Popliteus muscle, patella , MRI, t1, without, contrast, 3D, model, .stl, printable, meniscus,

    Free

  16. ADARSH KUMAR SHARMA

    SAG

    Version 1.0.0

    0 downloads

    About sag, knee, Vastus medialis muscle, Vastus lateralis muscle, Femur (shaft), Iliotibial tract, Medial collateral ligament, Lateral femoral condyle, Medial femoral condyle, Lateral meniscus (anterior horn), Lateral tibial condyle, Medial meniscus (anterior horn), Medial tibial condyle, Peroneus (fibularis) longus muscle, Extensor digitorum longus muscle, Tibia (shaft), Tibialis anterior muscle, knee, pes anserinus (superficial), Semimembranosus muscle (tibial attachment deep pesanserinus), Extensor digitorum longus muscle, Popliteus muscle, patella , MRI, t1, without, contrast, 3D, model, .stl, printable, meniscus,

    Free

  17. ADARSH KUMAR SHARMA

    Knee

    Version 1.0.0

    2 downloads

    knee replacement, Superior lateral genicular artery, Vastus medialis muscle, Vastus lateralis muscle, Superior medial genicular artery, Genicular anastomosis, Femur (shaft) Iliotibial tract, Medial collateral ligament, Lateral femoral condyle, Medial femoral condyle, Lateral meniscus (anterior horn), Descending genicular vein (articular branches), Lateral tibial condyle, Medial meniscus (anterior horn), Inferior lateral genicular artery, Medial tibial condyle, Peroneus (fibularis) longus muscle, Extensor digitorum longus muscle, Tibia (shaft), Tibialis anterior muscle, knee, pes anserinus (superficial), Semimembranosus muscle (tibial attachment deep pesanserinus), Extensor digitorum longus muscle, Popliteus muscle, patella , MRI, t1, without, contrast, 3D, model, .stl, printable, meniscus,

    Free

  18. ADARSH KUMAR SHARMA

    Brain

    Version 1.0.0

    3 downloads

    corona radiata, white, matter, MRI, tractography, corticospinal tract, corticobulbar tract, medial lemniscus, optic radiation, MRI, without,contrast, cerebellum, medulla, oblongata, head, brain,

    Free

  19. aminesara

    hospitalisation

    Version 1.0.0

    8 downloads

    Irm sep, head, neck, axial, stl, dicom, 3dmodel, print, brain, lobules, Frontal sinus, Frontal bone, Falx cerebri, Orbital gyri, Straight gyrus, Anterior cerebral artery, Anterior communicating artery, Internal carotid artery, Superior temporal gyrus, Middle temporal gyrus, Middle cerebral artery, Posterior communicating artery, Optic chiasm, Amygdaloid body, Pituitary stalk, Lateral ventricle (temporal horn), Dorsum sellae, Hippocampus, Pentagon of basal cisterns, Inferior temporal gyrus, Posterior cerebral artery, Parahippocampal gyrus, Tentorium cerebelli, Basilar artery and basal sulcus, Pons Sigmoid sinus, Cerebellar peduncle (middle), Fourth ventricle, Dentate nucleus, vermis of cerebellum (superior part), Temporal bone, Confluence of the sinuses, Cerebellar hemisphere, Transverse sinus, Occipital bone, thyroid, gland, carotid, yugular, maxilla, maxillary, sinus, hard, palate, nasopharynx, nasal septum, lower turbinates, mandible, MRI, T1, 3D, model, .stl, atlas, axis, dens, cervical, spine

    Free

  20. ThatsNotAMoon

    brainnn2

    Version 1.0.0

    4 downloads

    not too sure whats going on, head, neck, axial, stl, dicom, 3dmodel, print, brain, lobules, Frontal sinus, Frontal bone, Falx cerebri, Orbital gyri, Straight gyrus, Anterior cerebral artery, Anterior communicating artery, Internal carotid artery, Superior temporal gyrus, Middle temporal gyrus, Middle cerebral artery, Posterior communicating artery, Optic chiasm, Amygdaloid body, Pituitary stalk, Lateral ventricle (temporal horn), Dorsum sellae, Hippocampus, Pentagon of basal cisterns, Inferior temporal gyrus, Posterior cerebral artery, Parahippocampal gyrus, Tentorium cerebelli, Basilar artery and basal sulcus, Pons Sigmoid sinus, Cerebellar peduncle (middle), Fourth ventricle, Dentate nucleus, vermis of cerebellum (superior part), Temporal bone, Confluence of the sinuses, Cerebellar hemisphere, Transverse sinus, Occipital bone, maxilla, maxillary, sinus, hard, palate, nasopharynx, nasal septum, lower turbinates, mandible, MRI, t2. axial

    Free

  21. 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!
  22. Thanks to 3D printing understanding of the complex neural pathways of the human brain became a little bit easier. The Philadelphia-based Franklin Institute's new exhibit, Your Brain, features a striking 3D printed model of the white matter tracts of the human brain. White matter tracts are the pathways that nerve cells use to connect to each other inside the brain, and are incredibly complex. Dr. Jayatri Das, chief bioscientist at The Franklin Institute, incorporated the displays in a new expansion. The model was built from an MRI scan of a real brain and was then printed using the SLS print method from 3D Systems. It shows approximately 2000 tracts. Printing such a delicate structure proved to be quite a challenge and the project was turned down by several 3D printing bureaus before it was accepted by an outfit in Oklahoma. The model was printed in 10 separate parts and then assembled. This is truly an amazing advance in anatomic visualization. It's truly beautiful - a piece of art. For updates on news and new blog entries, follow us on Twitter at @Embodi3D. Source and images: 3D Systems
  23. NRRD is a file format for storing and visualizing medical image data. Its main benefit over DICOM, the standard file format for medical imaging, is that NRRD files are anonymized and contain no sensitive patient information. Furthermore NRRD files can store a medical scan in a single file, whereas DICOM data sets are usually comprised of a directory or directories that contain dozens if not hundreds of individual files. NRRD is thus a good file for transferring medical scan data while protecting patient privacy. This tutorial will teach you how to create an NRRD file from a DICOM data set generated from a medical scan, such as a CT, MRI, ultrasound, or x-rays. To complete this tutorial you will need a CD or DVD with your medical imaging scan, or a downloaded DICOM data set from one of many online repositories. If you had a medical scan at a hospital or clinic you can usually obtain a CD or DVD from the radiology department after signing a waiver and paying a small copying fee. Step 1: Download Slicer Slicer is a free software program for medical imaging. It can be downloaded from the www.slicer.org. Once on the Slicer homepage, click on the Download link as shown in Figure 1. Figure 1 Slicer is available for Windows, Mac, and Linux. Choose your operating system and download the latest stable release as shown in Figure 2. Figure 2: Download Slicer Step 2: Copy the DICOM files into Slicer. Insert your CD or DVD containing your medical scan data into your CD or DVD drive, or open the folder containing your DICOM files if you have a downloaded data set. If you navigate into the folder directory, you will notice that there are usually multiple DICOM files in one or more directories, as shown in Figure 3. Navigate to the highest level folder containing all the DICOM files. Figure 3: There are many DICOM files in a study Open Slicer. The welcome screen will show, as demonstrated in Figure 4. Left click on the folder that contains the DICOM files and drop it onto the Welcome panel in Slicer. Slicer will ask you if you want to load the DICOM files into the DICOM database, as shown in Figure 5. Click OK Slicer will then ask you if you want to copy the files or merely add links. Click Copy as shown in Figure 6. Figure 4: Drag and drop the DICOM folder onto the Slicer Welcome window. Figures 5 and 6 After working for a minute or two, Slicer will tell you that the DICOM import was successful, as shown in Figure 7. Click OK Figure 7 Step 3: Open the Medical Scan in Slicer. At this point you should see a window called the DICOM Browser, as shown in Figure 8. The browser has three panels, which show the patient information, study information, and the individual series within each study. If you close the DICOM Browser and need to open it again, you can do so under the Modules menu, as shown in Figure 9. Figure 8: DICOM Browser Figure 9: Finding the DICOM browser Each series in a medical imaging scan is comprised of a stack of images that together make a volume. This volume can be used to make the NRRD file. Modern CT and MRI scans typically have multiple series and different orientations that were collected using different techniques. These multiple views of the same structures allow the doctors reading the scan to have the best chance of making the correct diagnosis. A detailed explanation of the different types of CT and MRI series is beyond the scope of this article, but will be covered in a future tutorial. Click on the single patient, study, and a series of interest. Click the Load button as shown in Figure 8. The series will then begin to load as shown in Figure 10. Figure 10: The study is loading Step 4: Save the Imaging Data in NRRD Format Once the series loads you will see the imaging data displayed in the Slicer windows. Click the Save button on the upper left-hand corner, as shown in Figure 11. Figure 11: Click the Save button The Save Scene dialog box will then appear. Two or more rows may be shown. Put a checkmark next to the row that has a name that ends in ".nrrd". Uncheck all other rows. Click the directory button for the nrrd file and specify the directory to save the file into. Then click the save button, as shown in Figure 12. Figure 12: Check the NRRD file and specify save directory. The NRRD file will now be saved in the directory you specified!
  24. If you are planning on using the democratiz3D service to automatically convert a medical scan to a 3D printable STL model, or you just happen to be working with medical scans for another reason, it is important to know if you are working with a CT (Computed Tomography or CAT) or MRI (Magnetic Resonance Imaging) scan. In this tutorial I'll show you how to quickly and easily tell the difference between a CT and MRI. I am a board-certified radiologist, and spent years mastering the subtleties of radiology physics for my board examinations and clinical practice. My goal here is not to bore you with unnecessary detail, although I am capable of that, but rather to give you a quick, easy, and practical way to understand the difference between CT and MRI if you are a non-medical person. Interested in Medical 3D Printing? Here are some resources: Free downloads of hundreds of 3D printable medical models. Automatically generate your own 3D printable medical models from CT scans. Have a question? Post a question or comment in the medical imaging forum. A Brief Overview of How CT and MRI Works For both CT (left) and MRI (right) scans you will lie on a moving table and be put into a circular machine that looks like a big doughnut. The table will move your body into the doughnut hole. The scan will then be performed. You may or may not get IV contrast through an IV. The machines look very similar but the scan pictures are totally different! CT and CAT Scans are the Same A CT scan, from Computed Tomography, and a CAT scan from Computed Axial Tomography are the same thing. CT scans are based on x-rays. A CT scanner is basically a rotating x-ray machine that takes sequential x-ray pictures of your body as it spins around. A computer then takes the data from the individual images, combines that with the known angle and position of the image at the time of exposure, and re-creates a three-dimensional representation of the body. Because CT scans are based on x-rays, bones are white and air is black on a CT scan just as it is on an x-ray as shown in Figure 1 below. Modern CT scanners are very fast, and usually the scan is performed in less than five minutes. Figure 1: A standard chest x-ray. Note that bones are white and air is black. Miscle and fat are shades of gray. CT scans are based on x-ray so body structures have the same color as they don on an x-ray. How does MRI Work? MRI uses a totally different mechanism to generate an image. MRI images are made using hydrogen atoms in your body and magnets. Yes, super strong magnets. Hydrogen is present in water, fat, protein, and most of the "soft tissue" structures of the body. The doughnut of an MRI does not house a rotating x-ray machine as it does in a CT scanner. Rather, it houses a superconducting electromagnet, basically a super strong magnet. The hydrogen atoms in your body line up with the magnetic field. Don't worry, this is perfectly safe and you won't feel anything. A radio transmitter, yes just like an FM radio station transmitter, will send some radio waves into your body, which will knock some of the hydrogen atoms out of alignment. As the hydrogen nuclei return back to their baseline position they emit a signal that can be measured and used to generate an image. MRI Pulse Sequences Differ Among Manufacturers The frequency, intensity, and timing of the radio waves used to excite the hydrogen atoms, called a "pulse sequence," can be modified so that only certain hydrogen atoms are excited and emit a signal. For example, when using a Short Tau Inversion Recovery (STIR) pulse sequence hydrogen atoms attached to fat molecules are turned off. When using a Fluid Attenuation Inversion Recovery (FLAIR) pulse sequence, hydrogen atoms attached to water molecules are turned off. Because there are so many variables that can be tweaked there are literally hundreds if not thousands of ways that pulse sequences can be constructed, each generating a slightly different type of image. To further complicate the matter, medical scanner manufacturers develop their own custom flavors of pulse sequences and give them specific brand names. So a balanced gradient echo pulse sequence is called True FISP on a Siemens scanner, FIESTA on a GE scanner, Balanced FFE on Philips, BASG on Hitachi, and True SSFP on Toshiba machines. Here is a list of pulse sequence names from various MRI manufacturers. This Radiographics article gives more detail about MRI physics if you want to get into the nitty-gritty. Figure 2: Examples of MRI images from the same patient. From left to right, T1, T2, FLAIR, and T1 post-contrast images of the brain in a patient with a right frontal lobe brain tumor. Note that tissue types (fat, water, blood vessels) can appear differently depending on the pulse sequence and presence of IV contrast. How to Tell the Difference Between a CT Scan and an MRI Scan? A Step by Step Guide Step 1: Read the Radiologist's Report The easiest way to tell what kind of a scan you had is to read the radiologist's report. All reports began with a formal title that will say what kind of scan you had, what body part was imaged, and whether IV contrast was used, for example "MRI brain with and without IV contrast," or "CT abdomen and pelvis without contrast." Step 2: Remember Your Experience in the MRI or CT (CAT) Scanner Were you on the scanner table for less than 10 minutes? If so you probably had a CT scan as MRIs take much longer. Did you have to wear earmuffs to protect your hearing from loud banging during the scan? If so, that was an MRI as the shifting magnetic fields cause the internal components of the machine to make noise. Did you have to drink lots of nasty flavored liquid a few hours before the scan? If so, this is oral contrast and is almost always for a CT. How to tell the difference between CT and MRI by looking at the pictures If you don't have access to the radiology report and don't remember the experience in the scanner because the scan was A) not done on you, or you were to drunk/high/sedated to remember, then you may have to figure out what kind of scan you had by looking at the pictures. This can be complicated, but don't fear I'll show you how to figure it out in this section. First, you need to get a copy of your scan. You can usually get this from the radiology or imaging department at the hospital or clinic where you had the scan performed. Typically these come on a CD or DVD. The disc may already have a program that will allow you to view the scan. If it doesn't, you'll have to download a program capable of reading DICOM files, such as 3D Slicer. Open your scan according to the instructions of your specific program. You may notice that your scan is composed of several sets of images, called series. Each series contains a stack of images. For CT scans these are usually images in different planes (axial, coronal, and sagittal) or before and after administration of IV contrast. For MRI each series is usually a different pulse sequence, which may also be before or after IV contrast. Step 3: Does the medical imaging software program tell you what kind of scan you have? Most imaging software programs will tell you what kind of scan you have under a field called "modality." The picture below shows a screen capture from 3D Slicer. Looking at the Modality column makes it pretty obvious that this is a CT scan. Figure 3: A screen capture from the 3D Slicer program shows the kind of scan under the modality column. Step 4: Can you see the CAT scan or MRI table the patient is laying on? If you can see the table that the patient is laying on or a brace that their head or other body part is secured in, you probably have a CT scan. MRI tables and braces are designed of materials that don't give off a signal in the MRI machine, so they are invisible. CT scan tables absorb some of the x-ray photons used to make the picture, so they are visible on the scan. Figure 4: A CT scan (left) and MRI (right) that show the patient table visible on the CT but not the MRI. Step 5: Is fat or water white? MRI usually shows fat and water as white. In MRI scans the fat underneath the skin or reservoirs of water in the body can be either white or dark in appearance, depending on the pulse sequence. For CT however, fat and water are almost never white. Look for fat just underneath the skin in almost any part of the body. Structures that contained mostly water include the cerebrospinal fluid around the spinal cord in the spinal canal and around the brain, the vitreous humor inside the eyeballs, bile within the gallbladder and biliary tree of the liver, urine within the bladder and collecting systems of the kidneys, and in some abnormal states such as pleural fluid in the thorax and ascites in the abdomen. It should be noted that water-containing structures can be made to look white on CT scans by intentional mixing of contrast in the structures in highly specialized scans, such as in a CT urogram or CT myelogram. But in general if either fat or fluid in the body looks white, you are dealing with an MRI. Step 6: Is the bone black? CT never shows bones as black. If you can see bony structures on your scan and they are black or dark gray in coloration, you are dealing with an MRI. On CT scans the bone is always white because the calcium blocks (attenuates) the x-ray photons. The calcium does not emit a signal in MRI scans, and thus appears dark. Bone marrow can be made to also appear dark on certain MRI pulse sequences, such as STIR sequences. If your scan shows dark bones and bone marrow, you are dealing with an MRI. A question I am often asked is "If bones are white on CT scans, if I see white bones can I assume it is a CT?" Unfortunately not. The calcium in bones does not emit signal on MRI and thus appears black. However, many bones also contain bone marrow which has a great deal of fat. Certain MRI sequences like T1 and T2 depict fat as bright white, and thus bone marrow-containing bone will look white on the scans. An expert can look carefully at the bone and discriminate between the calcium containing cortical bone and fat containing medullary bone, but this is beyond what a layperson will notice without specialized training. Self Test: Examples of CT and MRI Scans Here are some examples for you to test your newfound knowledge. Example 1 Figure 5A: A mystery scan of the brain Look at the scan above. Can you see the table that the patient is laying on? No, so this is probably an MRI. Let's not be hasty in our judgment and find further evidence to confirm our suspicion. Is the cerebrospinal fluid surrounding the brain and in the ventricles of the brain white? No, on this scan the CSF appears black. Both CT scans and MRIs can have dark appearing CSF, so this doesn't help us. Is the skin and thin layer of subcutaneous fat on the scalp white? Yes it is. That means this is an MRI. Well, if this is an MRI than the bones of the skull, the calvarium, should be dark, right? Yes, and indeed the calvarium is as shown in Figure 5B. You can see the black egg shaped oval around the brain, which is the calcium containing skull. The only portion of the skull that is white is in the frontal area where fat containing bone marrow is present between two thin layers of calcium containing bony cortex. This is an MRI. Figure 5B: The mystery scan is a T1 spoiled gradient echo MRI image of the brain. Incidentally this person has a brain tumor involving the left frontal lobe. Example 2 Figure 6A: Another mystery scan of the brain Look at the scan above. Let's go through our process to determine if this is a CT or MRI. First of all, can you see the table the patient is lying on or brace? Yes you can, there is a U-shaped brace keeping the head in position for the scan. We can conclude that this is a CT scan. Let's investigate further to confirm our conclusion. Is fat or water white? If either is white, then this is an MRI. In this scan we can see both fat underneath the skin of the cheeks which appears dark gray to black. Additionally, the material in the eyeball is a dark gray, immediately behind the relatively white appearing lenses of the eye. Finally, the cerebrospinal fluid surrounding the brainstem appears gray. This is not clearly an MRI, which further confirms our suspicion that it is a CT. If indeed this is a CT, then the bones of the skull should be white, and indeed they are. You can see the bright white shaped skull surrounding the brain. You can even see part of the cheekbones, the zygomatic arch, extending forward just outside the eyes. This is a CT scan. Figure 6B: The mystery scan is a CT brain without IV contrast. Example 3 Figure 7A: A mystery scan of the abdomen In this example we see an image through the upper abdomen depicting multiple intra-abdominal organs. Let's use our methodology to try and figure out what kind of scan this is. First of all, can you see the table that the patient is laying on? Yes you can. That means we are dealing with the CT. Let's go ahead and look for some additional evidence to confirm our suspicion. Do the bones appear white? Yes they do. You can see the white colored thoracic vertebrae in the center of the image, and multiple ribs are present, also white. If this is indeed a CT scan than any water-containing structures should not be white, and indeed they are not. In this image there are three water-containing structures. The spinal canal contains cerebrospinal fluid (CSF). The pickle shaped gallbladder can be seen just underneath the liver. Also, this patient has a large (and benign) left kidney cyst. All of these structures appear a dark gray. Also, the fat underneath the skin is a dark gray color. This is not in MRI. It is a CT. Figure 7B: The mystery scan is a CT of the abdomen with IV contrast Example 4 Figure 8A: A mystery scan of the left thigh Identifying this scan is challenging. Let's first look for the presence of the table. We don't see one but the image may have been trimmed to exclude it, or the image area may just not be big enough to see the table. We can't be sure a table is in present but just outside the image. Is the fat under the skin or any fluid-filled structures white? If so, this would indicate it is an MRI. The large white colored structure in the middle of the picture is a tumor. The fat underneath the skin is not white, it is dark gray in color. Also, the picture is through the mid thigh and there are no normal water containing structures in this area, so we can't use this to help us. Well, if this is a CT scan than the bone should be white. Is it? The answer is no. We can see a dark donut-shaped structure just to the right of the large white tumor. This is the femur bone, the major bone of the thigh and it is black. This cannot be a CT. It must be an MRI. This example is tricky because a fat suppression pulse sequence was used to turn the normally white colored fat a dark gray. Additionally no normal water containing structures are present on this image. The large tumor in the mid thigh is lighting up like a lightbulb and can be confusing and distracting. But, the presence of black colored bone is a dead giveaway. Figure 8B: The mystery scan is a contrast-enhanced T2 fat-suppressed MRI Conclusion: Now You Can Determine is a Scan is CT or MRI This tutorial outlines a simple process that anybody can use to identify whether a scan is a CT or MRI. The democratiz3D service on this website can be used to convert any CT scan into a 3D printable bone model. Soon, a feature will be added that will allow you to convert a brain MRI into a 3D printable model. Additional features will be forthcoming. The service is free and easy to use, but you do need to tell it what kind of scan your uploading. Hopefully this tutorial will help you identify your scan. If you'd like to learn more about the democratiz3D service click here. Thank you very much and I hope you found this tutorial to be helpful. Nothing in this article should be considered medical advice. If you have a medical question, ask your doctor.
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    This Brain model was created from a high resolution MRI scan. The model includes the cerebrum. The cerebellum and brain stem are not depicted. The model has been made hollow, with 4 mm wall thickness to save on material when 3D printing. The model is full-size. It has been successfully printed at full size on an Ultimaker 3 Extended printer, and at 95% size on a Formlabs Form 2 printer. Technical parameters: Vertices: 350725 Triangles: 701950 Size: 17.9 x 13.4 x 11.5 cm

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