DEXA SCAN BONE MINERAL DENSITY - THREE SITES (SPINE, HIP & FOREARM)

DEXA stands for Dual-Energy X-ray Absorptiometry. The name reflects the technology it uses: two distinct, low-dose X-ray beams are passed through your bones. One beam is primarily absorbed by soft tissue, while the other is absorbed by bone. By measuring the difference, the DEXA machine can calculate a highly precise and accurate measurement of your bone mineral density (BMD).

Unlike a standard X-ray, which can only detect significant bone loss (typically over 30-40%), a DEXA Scan (Bone Density Test) can identify even small changes in bone density. This makes it the gold standard for early detection and diagnosis. The scan focuses on the most common sites for osteoporotic fractures: the hip and the lumbar spine.

Types of DEXA Scans

There are two main types of bone density tests:

Central DEXA

This is the most common and comprehensive type of DEXA Scan (Bone Density Test). It involves a large machine where you lie on a padded table. The scanner measures bone density in your hip and spine—the most critical areas for assessing osteoporosis. A central DEXA scan is the definitive standard for diagnosis and for monitoring changes in bone density over time or in response to treatment.

Peripheral DEXA (pDEXA)

Peripheral devices are smaller, portable machines that measure bone density in the wrist, heel, or finger. These are often used for general screening purposes, such as at health fairs. While convenient, a pDEXA is not used for a definitive diagnosis of osteoporosis. If a peripheral test indicates potential bone loss, your doctor will almost always recommend a follow-up central DEXA scan for confirmation.

The primary goal of a DEXA Scan (Bone Density Test) is to precisely quantify your bone health. It does this by measuring Bone Mineral Content (BMC) and the area of the bone being scanned. From these, it calculates the key parameter: Bone Mineral Density (BMD). Your report will then translate this BMD value into two important comparative scores.

• T-score: This is the most important score for diagnosing osteoporosis. It compares your BMD to the peak bone density of a healthy, young adult of the same sex. The T-score is a measure of how far your bone density deviates from the young adult average.
• Z-score: This score compares your BMD to the average BMD of a person of your same age, sex, and ethnicity. The Z-score is not typically used for diagnosis in post-menopausal women or older men. However, if the Z-score is unusually low (e.g., -2.0 or lower), it may alert your doctor to investigate potential secondary causes of bone loss beyond simple aging.
• Fracture Risk Assessment (FRAX® score): Many DEXA scan reports at Cadabam's diagnostics may also include a FRAX® score. This is an algorithm developed by the World Health Organization that uses your BMD along with other clinical risk factors (like age, smoking, family history) to calculate your 10-year probability of having a major osteoporotic fracture.

There are three primary clinical reasons for undergoing a bone density test:

1. To Diagnose Osteopenia and Osteoporosis: The test can definitively diagnose both osteopenia (low bone mass, a precursor to osteoporosis) and osteoporosis itself, often long before any symptoms appear or a fracture occurs.
2. To Predict Your Risk of Future Fractures: Your T-score is a powerful predictor of your likelihood of breaking a bone in the future. This information empowers you and your doctor to take preventive action.
3. To Monitor Treatment or Bone Loss: For patients diagnosed with osteoporosis and undergoing treatment, follow-up DEXA scans are essential to determine if the medication is working to slow or reverse bone loss.

When and Who Needs to Take a DEXA Scan?

Your doctor may recommend a DEXA Scan (Bone Density Test) based on your age, medical history, and specific risk factors. It is a crucial diagnostic tool for several groups of people.

Common indications for the test include:

• Post-menopausal women: Oestrogen, which helps protect bones, drops significantly after menopause, increasing bone loss.
• Men over 50 with risk factors: While less common than in women, men are also at risk for osteoporosis, especially with certain lifestyle factors or medical conditions.
• Individuals with a family history: A parental history of hip fracture is a significant risk factor.
• Those on long-term steroid medication: Medications like prednisone can accelerate bone loss.

Symptoms or conditions that may prompt a scan:

• An unexplained loss of height (more than an inch).
• A fragility fracture (breaking a bone with minimal trauma).
• Certain endocrine disorders like hyperthyroidism or hyperparathyroidism.
• Conditions like rheumatoid arthritis, which can impact bone health.
• Patients undergoing specific treatments for prostate or breast cancer.

Benefits of Taking the Test

Investing in a DEXA Scan (Bone Density Test) offers significant health benefits:

• Early Detection: It is the only test that can diagnose low bone density at its earliest, most manageable stage.
• Accurate Diagnosis: Provides precise, quantitative data, allowing for a reliable diagnosis and eliminating guesswork.
• Guides Treatment: The results are crucial for helping your doctor create a personalized management plan, which may include lifestyle adjustments, dietary changes, specific exercises, and, if necessary, medication.

Illness Diagnosed with DEXA Scan

The DEXA Scan (Bone Density Test) is the primary tool used to diagnose two key conditions related to bone health:

• Osteoporosis: A disease characterized by low bone mass and structural deterioration of bone tissue, leading to increased bone fragility and a high risk of fractures.
• Osteopenia: A condition where bone mineral density is lower than normal but not yet low enough to be classified as osteoporosis. It is considered a warning sign that you are at a higher risk for developing osteoporosis.

Preparing for your DEXA Scan (Bone Density Test) at Cadabam's diagnostics is simple and requires minimal effort.

• You can eat and drink normally on the day of your appointment. There is no need to fast.
• Key Instruction: You must avoid taking calcium supplements, multivitamins, or antacids containing calcium for at least 24 hours before your scan. These can interfere with the accuracy of the test results.
• Clothing: Wear loose, comfortable clothing. Avoid clothes with metal zippers, belts, hooks, or buttons around your abdomen and hip area. Sweatpants and a t-shirt are ideal. You may be asked to change into a gown if your clothing has metal fasteners.

Pre-requisites

• A doctor's referral or prescription is generally required to schedule a DEXA Scan (Bone Density Test).
• Important: If you have recently had a barium study (for a GI series) or a scan that required an injection of contrast material (like a CT or nuclear medicine scan), you must inform our staff when booking. You may need to wait 10 to 14 days before having your DEXA scan, as the contrast agent can interfere with the results.

Best Time to Take the DEXA Scan

There is no "best" time of day to have a DEXA scan. The test's accuracy is not affected by the time of day, your diet on that day (aside from avoiding calcium supplements), or, for women, your menstrual cycle. You can schedule it at your convenience.

Eligibility

Most adults are eligible for a DEXA scan, especially if they meet the risk criteria outlined above. The primary contraindication is pregnancy.

• The test is not recommended for individuals who are pregnant or suspect they might be pregnant due to the use of X-rays, even at a very low dose.

Procedure for Taking a DEXA Scan

The dexa scan procedure for osteoporosis is straightforward, quick, and entirely painless. Here’s what you can expect:

1. Check-in: You will register at the front desk at Cadabam's diagnostics.
2. Positioning: A certified radiologic technologist will guide you into the scanning room and ask you to lie down on your back on a padded table.
3. Alignment: The technologist will carefully position you to ensure accurate measurements. For the spine scan, your legs will be elevated and supported on a padded box to help flatten your pelvis and lower back. For the hip scan, your foot may be placed in a brace to rotate your hip inward slightly.
4. Scanning: A C-shaped scanning arm will move slowly above you, and a detector will pass underneath the table. The arm will not touch you. You simply need to breathe normally and remain as still as possible during the scan. Any movement can blur the image and affect the results.
5. Completion: The entire procedure typically takes only 10 to 20 minutes to complete. Once finished, you can get up and resume your normal activities immediately.

Caution Before Taking the Test

Your safety and the accuracy of your test are our top priorities. Before the scan begins, you must inform the technologist about two crucial things:

• Possibility of Pregnancy: It is essential to tell the technologist if there is any chance you could be pregnant.
• Metallic Implants: Let the technologist know if you have any metal in your body, particularly a hip replacement, spinal rods, or surgical screws in your spine. This information helps the radiologist interpret your scan correctly, as metal can artefactual affect the BMD reading in that specific area.