Finding the right tests…
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Emergency services available 24 x 7
Finding the right tests…
CT Scan
CT bone analysis measures how dense your bone actually is, using a CT scanner alongside a calibration reference to convert the scan's raw readings into a bone mineral density value - a technique generally known as quantitative CT. It looks at the spine or hip and can separate the two main types of bone, the dense outer shell and the honeycomb-like inner bone, which a standard DEXA bone density scan reports together as a single number. Doctors use it as an alternative to DEXA, or opportunistically on a CT scan someone already had for another reason, to assess fracture risk from conditions like osteoporosis. It's not the same as a routine CT looking for a fracture or tumor.
This scan calculates a bone mineral density value from your CT images, using a calibration reference alongside the scan. It's used to assess fracture risk from bone thinning, such as osteoporosis, and can look at the spine or hip's inner and outer bone separately. Your doctor interprets the result against standard thresholds.
Quantitative CT, often shortened to QCT, uses a standard CT scanner together with a calibration phantom to convert the raw brightness values in the images into an actual bone mineral density measurement. It's a different approach from DEXA, the low-dose X-ray scan most commonly used for bone density, though both aim to answer the same question: how strong is your bone.
QCT reports a true volumetric density and can separate the dense outer shell of bone from the softer, honeycomb-like inner bone, rather than reporting one combined number the way DEXA does. It can also be applied to a CT scan a patient already had for an unrelated reason, without a separate test or extra radiation.
- Assessing bone density at the spine or hip - Monitoring bone loss over time in some conditions - An alternative when DEXA isn't available or practical
QCT and DEXA don't report results on quite the same scale, so results from one aren't directly interchangeable with the other. Ask your doctor how your result should be interpreted and whether DEXA is more appropriate for follow-up.
DEXA is a low-dose X-ray test that's the standard way to check bone density. This test uses a CT scanner with a calibration reference instead, and can separate the dense outer bone from the softer inner bone, which DEXA reports as one combined number.
It gives your doctor a bone density measurement that helps assess fracture risk, including conditions like osteoporosis. Your doctor combines this with your history and other tests to reach a diagnosis.
Sometimes, yes. If you've already had a CT scan of your spine or hip for another reason, that data can sometimes be reanalysed for bone density without scanning you again.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
It typically uses a similar radiation dose to the CT scan of that body region. Ask your doctor or the centre how this compares to DEXA, which generally involves lower radiation.
Not directly - the two tests report bone density on different scales, so the numbers aren't simply interchangeable. Ask your doctor how to interpret your result alongside any previous DEXA test.
It's generally used for people whose bone density needs checking through CT, whether that's a first assessment or because DEXA isn't a practical option for them. Your doctor decides based on your history and risk factors.
Preparation is generally minimal, mainly removing metal objects near the area being scanned. Ask your doctor or the centre about anything specific to your appointment.
The scan itself is quick, usually just a few minutes. Ask the centre for a more precise estimate on the day.