Modern Tests Used for Bone Imaging
by Brett Torina July 14, 2021 Education
What is Bone Imaging?
How Can Bone Imaging Help Diagnose a Problem?
5 Modern Bone Imaging Options Available Today
Bone Density Tests (DEXA / DXA)
Bone Scintigraphy
2 Additional Tests that can Help Determine Bone Health
Bone/Bone Marrow Biopsies
How Clarke Bioscience Uses Bone Imaging to Help Understand Our Customers
Though we can't see them with the naked eye, bones make up one of the most critical systems in the human body. They provide support and structure for the musculatory system while also protecting some of your most sensitive organs. However, bones are also susceptible to illness, injury, and disease. This is what makes bone imaging so valuable.
Bone imaging is exactly as it sounds: the ability to create images of our bones. It includes a group of specialized procedures that can be used to examine your bones and diagnose problems that may exist within them. Bone imaging is revolutionary because it allows doctors and researchers to see inside without cutting the body.
This article focuses on the true medical value of bone imaging and how it is used to diagnose disease and save lives. Then, we're looking at the five (5) main types of bone imaging tests currently available and the amount of information and insight they provide.
There are more than 200 bones in the human body, so singling just one or two out for examination can be challenging. This is especially true when dealing with bone injuries and pain, which is why bone scans are so vital. The technology allows medical professionals to see the bones, study them, and diagnose a wide range of disorders in a noninvasive way. Some bone scan procedures are used for viewing the entire skeleton in just one scan.
In 1895, the very first X-ray of a human bone was produced.[1] The advancement came through pure happenstance, but the image revolutionized medicine and sparked a whirlwind of medical imaging capabilities. Today, medical professionals have a wide range of tests and procedures to choose from when examining the health of the bones. Here are several of them:
As mentioned above, x-rays were the first images to show scientists that viewing bones was even possible. While experimenting with different electrical currents, German physicist Wilhelm Röntgen found that certain invisible electromagnetic rays would pass through his flesh but not bone. Oddly enough, this resulted in an image where the bones were highlighted and incredibly visible. The breakthrough was so celebrated that Röntgen went on to earn the Nobel Prize in 1901 for this discovery.
Like many forms of medical imaging, x-rays rely on radiation to work. This specific technology takes advantage of the makeup in your bones to produce images where they "glow." This is because different parts of your body absorb different levels of radiation. Bones absorb the most. Because of this, they appear white in x-ray images, where fat and other soft tissues look to be gray or even black.
Image Credit: AAP [2]
X-rays are one of the simplest forms of medical imaging and don't take long to complete. During an x-ray, the patient may be sitting or standing depending on the particular bones being imaged, but usually, only 10-15 minutes are required. X-rays are most well known for diagnosing fractures and breaks, but they can also be used to identify infection, arthritis, bone loss, and even some tumors.
Above, you will see an image with six x-rays that show the skeletal maturation process in children. Each image is taken from the same child every two years, between 5 and 15 years old.
Though CT (Computed Tomography) uses radiation and X-ray technology, more than 80 years sit between the two scientific discoveries. The first CT scanner was developed in 1972 by Gary Hounsfield, an electrical engineer who'd never worked in medicine.[3] Hounsfield theorized that multiple X-ray exposures could be used to create images that better highlight bones and other internal structures. And he was right!
CT scans allow doctors and researchers to gain more detailed information about the bones and bone tissue. Unlike a traditional X-ray, where the beam stays in one place, the CT scan moves around the body. This allows for multiple different views of the same bone.
Image Credit: Semantic Scholar [4]
Above, you will see the CT scan of a bone marrow biopsy. A needle is being inserted into the marrow space of the left side of the pelvis, and the CT is being used in real-time to guide the medical team in their efforts.
For the most part, CT scans take about 30 minutes to one hour to complete and require the patient to remain extremely still during the procedure. CT scans are used to identify damage and injuries, disease, and other abnormalities. CT scans provide more detailed imaging than traditional X-rays, so they can be beneficial when initial imaging is inconclusive.
The 1970s also brought another new, groundbreaking advancement in bone imaging technology. American physician Raymond Damadian was hard-at-work on his full-body MRI scanner, which promised to provide images of the bones and other tissue without the use of radiation. In 1977, the very first MRI image of a human chest was taken.[5]
MRI (Magnetic Resonance Imaging) uses a giant magnet to create images of the bones and tissues. The technology temporarily redirects the hydrogen atoms in the body and then forms 2D images of the bone structure based on the activity of those atoms. Therefore, MRI is most effective for examining soft tissues.
Above, you will see two MRI images from someone with bone cancer of the femur. Panel A shows microscopic cancer cells, while Panel B reveals the entire osteosarcoma tumor. Each image is another layer of the same bone.
An MRI can last for up to 90 minutes, depending on the size of the area being scanned. It's also important to note that metal should never enter an MRI because the technology relies on a giant magnet. This includes medical devices like pacemakers, metal pins, and even certain types of birth control.
An MRI can help identify bone issues like disease and injury and also be used to monitor the bone marrow.
The very first instance of digital radiography was recorded in a bone densitometry scan. This instrument, developed by Professor John R. Cameron in 1960, helps determine bone health and density.[7] Today, it's incredibly helpful in detecting and diagnosing osteoporosis before the first break.
Also known as a DEXA/DXA scan, the bone density test uses radiation to determine the strength and thickness of the bones. These scans can be conducted on the entire skeleton or focus only on certain bones like the hip, spine, or wrist. Two separate X-ray beams pass through the body during the test, and these help doctors determine the mass within a bone.
Image Credit: European Radiology[8]
Above, you will see bone density scans taken from 3 separate patients to predict future hip injuries. Patients 1 and 2 show clear signs of bone loss and may benefit from some protective measures to prevent damage in the future.
Bone density scans don't take long at all, generally under half an hour. Because they are used primarily as a preventative, bone density scans are recommended for most people after a certain age.
Bone scintigraphy is unlike any of the other bone scans mentioned today. This is a form of nuclear medicine, which involves applying a radioactive substance (often called a "tracer") to highlight your bones during the scan. Bone scintigraphy is an ever-evolving field, with many brilliant minds to thank, but some of the earliest accounts of it date back to the 1960s.[9]
Also known as a bone scan or a nuclear bone test, bone scintigraphy is highly detailed and time-consuming. Before the imaging test, the tracer is injected into the vein and allowed to circulate for two to four hours. Once the patient has eliminated any excess tracer by using the restroom, the scan can begin. A full-body scan can last up to 2 hours and requires the patient to stay still during the procedure.
Image Credit: JNMT [10]
Above, you will see two bone scintigraphy images taken to detect prostate cancer, which has spread throughout the patient's body.
The darkened spots indicate areas where the tracer has accumulated within the cancer cells.
A bone scan can help assess trauma, find complex fractures, investigate unexplained bone pain, and monitor bone disease. Bone scans are also highly common in patients with cancer.
Bone imaging is not the only way that doctors and researchers can determine the health of a bone. There are also other tests that can be administered. They include:
Bone/Bone Marrow Biopsies:
A biopsy is a procedure where a small piece of the bone or bone marrow is removed for testing. A CT scan or MRI could be included to help guide a doctor through this procedure. Bone and bone marrow biopsies can help monitor abnormal cells and other blood and bone conditions, like cancer and anemia.
The Bone Mineral Density (BMD) Test:
Measures the number of minerals present in your bones. The BMD test helps diagnose osteoporosis and predict your risk of bone fractures. Bone Mineral Density Tests can sometimes be completed with a urine sample. The minerals they look for in the bone include:
Bone-Specific Alkaline Phosphatase (BALP) to estimate the rate of bone formation throughout the skeleton
Osteocalcin to help determine bone mineralization
Urinary N-telopeptide (uNTX) to predict skeletal events
Vitamin D which is critical for calcium absorption
At Clarke Bioscience, we believe in targeted therapies. We know that no medicine is as effective as tailored medicine, which is why we utilize bone imaging in all of our research. We're dedicated to understanding how your body works and pride ourselves on continuous research and advancement. Our tailored therapies for supporting the body's natural healing capabilities aim to keep you healthy for life.
When medicine was granted the ability to view the happenings of the body without cutting it, advancements took off at light speed. Bone imaging is the same. By understanding our very framework, we can identify ways to support ourselves and our bodies better. The skeleton is the best place to start.
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(2017, December). Bone Age: A Handy Tool for Pediatric Providers. AAP. https://pediatrics.aappublications.org/content/140/6/e20171486
Ambrose, R. (n.d.). Godfrey Hounsfield. Radiopaedia. https://radiopaedia.org/articles/godfrey-hounsfield?lang=us
Badiola, C. (2012). CT Guided Bone Marrow Aspiration and Core Biopsy. Semantic Scholar. https://www.semanticscholar.org/paper/CT-Guided-Bone-Marrow-Aspiration-and-Core-Biopsy-Badiola-Scappaticci/7e45dbeab1ce79061c6caff6d01991080fb72bff
University of Washington. (n.d.). Featured History: Magnetic resonance imaging. https://rad.washington.edu/blog/featured-history-magnetic-resonance-imaging/
Zampa, V. (2010). MRI of bone tumors: advances in diagnosis and treatment assessment. Semantic Scholar. https://www.semanticscholar.org/paper/MRI-of-bone-tumors%3A-advances-in-diagnosis-and-Zampa-Roselli/75ff27b048b1a02cc3ecc86807bd544387ca58c8
Rad, A. (n.d.). In memory of Professor John R. Cameron (1922-2005). In memory of Professor John R. Cameron (1922-2005).http://ijrr.com/article-1-81-en.pdf
Wilczeck, M. (2012). Digital X-ray radiogrammetry of hand or wrist radiographs can predict hip fracture risk - A study in 5,420 women and 2,837 men. European Radiology. https://www.researchgate.net/publication/233891748_Digital_X-ray_radiogrammetry_of_hand_or_wrist_radiographs_can_predict_hip_fracture_risk_-_A_study_in_5420_women_and_2837_men
Bridges, R. (2007, June). An Introduction to Na18F Bone Scintigraphy: Basic Principles, Advanced Imaging Concepts, and Case Examples. JNMT. https://tech.snmjournals.org/content/35/2/64#
Kumar, R. (2016, Dec 1). The Role of 18F-Sodium Fluoride PET/CT Bone Scans in the Diagnosis of Metastatic Bone Disease from Breast and Prostate Cancer. JNMT. https://tech.snmjournals.org/content/44/4/217