REMS
Also called: Radiofrequency Echographic Multi Spectrometry, Echolight, REMS scan
What it means
REMS is an ultrasound-based scan that estimates bone density and tissue quality at the spine and hip without using radiation.
Knowing your bone density and tracking changes over time helps you and your healthcare provider understand your fracture risk and monitor your bone health.
REMS stands for Radiofrequency Echographic Multi Spectrometry, sometimes known by the brand name Echolight. Instead of using X-rays like a DEXA scan, it uses ultrasound to look at your spine and hip. It analyzes the raw echo signal that comes back and compares it to reference models, producing its own T-score (not directly interchangeable with a DEXA T-score), plus a separate fragility score that gives a sense of tissue quality rather than just density.
Because it doesn't use radiation, REMS can be repeated more often, and it isn't thrown off by arthritis or calcium buildup the way a lumbar spine DEXA sometimes can be. Validation studies have shown good agreement between REMS and DEXA, along with REMS independently helping predict fracture risk over a five-year follow-up period.
That said, REMS is newer than DEXA and doesn't yet have as much long-term outcome data behind it. It's best thought of as a strong complement to DEXA rather than a replacement for it. If you already have a history of DEXA scans, it's worth continuing those so your results stay comparable over time.
How sure is this?
Graded Emerging Evidence: Promising research, but findings are still developing and may be primarily from laboratory or animal studies. Read each study with its grade in mind. One study is a piece of the picture, not the whole of it.
Where the Academy teaches it
This page is the short version. The lessons teach it in full, with the context around it and a quiz to lock it in.
Questions people ask about this
A DEXA scan uses a low dose of X-ray to measure bone mineral density at the hip and spine, and it's the long-established standard that generates your T-score. A REMS scan uses ultrasound instead of radiation to assess the same areas, comparing the echo signal to reference models to produce its own T-score (not directly interchangeable with a DEXA T-score) plus a separate "fragility score" reflecting tissue quality. REMS is newer, has less long-term data, and is best used alongside DEXA rather than replacing it, especially if you already have a DEXA history.
Read the full answer →For most people, the honest answer is every 1 to 2 years. DEXA machines have a built-in measurement error, and most facilities can't reliably detect a real change in bone density sooner than that — a small shift of 1-2% on your scan often just reflects machine noise, not actual bone loss or gain. Your physician can tell you the right interval for your specific situation.
Read the full answer →Related words
A DEXA scan is a low-radiation X-ray test that measures how much mineral is in your hip and spine bones, giving you…
A T-score shows how your bone density compares to a healthy young adult, measured in standard deviations, and it's…
A Z-score compares your bone density to other people your own age and sex, which matters most for younger adults,…
Bone mineral density (BMD) measures how much mineral is packed into your bones, usually estimated with a DEXA scan,…
Trabecular Bone Score (TBS) is a measurement taken from your spine DEXA image that estimates how well-connected your…
A fragility fracture is a broken bone caused by a fall or bump that normally wouldn't break a healthy bone, often at…
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