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If you’ve been told to get a bone density scan, you’ve likely heard of a DEXA scan.

A newer technology is now available at BioStrong Avenida in Calgary called REMS (Radiofrequency Echographic Multi Spectrometry).

What’s the difference between DEXA and REMS?  Are they interchangeable?  And which one should you choose?

Let’s break it down clearly.

What Is a DEXA Scan?

DEXA (Dual-Energy X-ray Absorptiometry) has long been considered the standard test for measuring bone mineral density (BMD).

DEXA works by:

• Using low-dose X-rays
• Measuring how much radiation is absorbed by bone
• Calculating bone mineral density in grams per square centimeter (g/cm²)

From this, it generates:

• T-score
• Z-score
• Fracture risk calculations (often using FRAX)

DEXA is widely used in hospitals and diagnostic imaging clinics across Canada.

What Is REMS (Echolight)?

REMS stands for Radiofrequency Echographic Multi Spectrometry.

REMS works by:

• Using ultrasound technology
• Does not use radiation
• Analyzes raw radiofrequency signals reflected from bone
• Evaluates both mineral density and bone microarchitecture

REMS produces:

• BMD (g/cm²)
• T-score
• Z-score
• Fragility Score
• 5-year fracture risk estimation

At BioStrong Avenida, we use the Echolight REMS scanner, a radiation-free diagnostic tool designed to provide accurate and repeatable bone health assessments.

Key Differences Between DEXA and REMS

1️⃣ Radiation Exposure

• DEXA: Uses low-dose X-ray radiation
• REMS: No radiation (ultrasound-based)

This makes REMS suitable for:

• More frequent follow-up monitoring
• Patients concerned about cumulative radiation exposure
• Getting a baseline before age 50

2️⃣ What Is Being Measured

DEXA primarily measures:

• Bone mineral content (density)

REMS evaluates:

• Bone mineral density
• Structural signal patterns
• Indicators related to bone microarchitecture

This means REMS may provide additional insight into bone fragility beyond mineral content alone.

3️⃣ Degenerative Artifacts

In older adults, DEXA scans of the lumbar spine can be influenced by:

• Osteoarthritis
• Calcifications
• Degenerative changes

These factors can artificially elevate spine BMD readings.

REMS uses spectral filtering of raw ultrasound signals, which may reduce interference from degenerative artifacts, potentially providing a clearer picture in certain populations.

4️⃣ Longitudinal Tracking

Both DEXA and REMS calculate percentage change using:

(New BMD − Old BMD) ÷ Old BMD × 100

However:

• You must use the same technology for follow-up comparison.
• DEXA and REMS are not interchangeable for tracking progress.

At BioStrong, if you begin with REMS, we recommend follow-up scans using the same system to ensure accurate longitudinal monitoring.

Are They Both Clinically Valid?

Yes.

Multiple validation studies have shown REMS measurements to be comparable to DEXA for lumbar spine and femoral neck BMD assessment.

DEXA remains widely accepted in hospital systems and is often required for pharmacological treatment decisions.

REMS offers:

• No radiation
• Microarchitectural insight
• Practical repeat testing capability

Each has value depending on the clinical situation.

What About T-Scores?

Both DEXA and REMS generate T-scores.

A T-score compares your bone density to an average 30-year-old adult of the same sex:

• Normal: –1.0 or higher
• Osteopenia: –1.0 to –2.5
• Osteoporosis: –2.5 or lower

T-scores are derived from absolute BMD measurements — not the other way around.

Why BioStrong Uses REMS at Our Avenida Location

At BioStrong, our focus is proactive bone health — not just diagnosis after fracture.

The Echolight REMS scanner allows us to:

• Measure bone density without radiation
• Track changes safely over time
• Monitor response to osteogenic loading
• Assess fragility risk
• Provide immediate in-clinic results
• Measure a baseline during BMD peak time of life (age 30-40)

For patients engaged in structured mechanical loading programs, REMS allows practical follow-up without radiation concerns.

Which One Should You Choose?

If your physician specifically requests DEXA, follow their recommendation.

If you are:

• Curious about your bone density
• Wanting baseline screening
• Monitoring osteopenia
• Tracking progress during a bone-building program
• Interested in radiation-free assessment

REMS may be an excellent option.

🧠 How REMS/Echolight Tracks Longitudinal Change vs. DEXA

Like DEXA, REMS (Radiofrequency Echographic Multi-Spectrometry) provides measurements of bone mineral density (BMD) in g/cm², which allows comparison over time. However, the two technologies analyze data very differently.

🦴 1. Comparable Accuracy to DEXA

Multiple studies have shown that REMS correlates well with standard DEXA measurements and can identify osteoporosis with similar diagnostic accuracy:

• A real-world clinical study of 343 women found strong agreement between REMS and DEXA BMD outcomes for spine and hip, with low coefficients of variation, meaning high precision for repeated measures.
• Systematic reviews and meta-analyses find REMS performs comparably for osteoporosis detection and shows high correlation with DEXA across diverse populations.

This means when you scan the same person with REMS at different times (e.g., baseline vs. 6–12 months later), you can calculate percent change much the same way as with DEXA:

🧪 2. REMS Precision and Repeatability

Studies show:

• REMS has excellent intra-operator precision (variation as low as ~0.3–1.0%), meaning the same operator repeating the scan will get very similar results.
• Inter-operator precision (different operators scanning the same person) is also strong, which is important for clinical follow-up.

Because REMS excludes artifact data and analyzes raw radiofrequency signals, it can sometimes avoid the false elevation that can occur in DEXA (e.g., due to osteoarthritis or calcification).

🧠 3. Diagnostic Agreement Across Populations

In specific populations (e.g., systemic lupus erythematosus), REMS and DEXA showed moderate correlation in BMD and fracture risk discrimination — supporting its use as a monitoring tool even in complex clinical settings.

📊 How REMS/Echolight Assesses Body Composition

Unlike traditional bone-only devices, REMS/Echolight can also estimate body composition parameters during the same scanning session. This includes:

• Fat mass (total & percentage)
• Fat-free mass (lean mass)
• Basal metabolic rate (BMR) estimates
• Body water and protein/mineral distribution

A clinical abstract comparing REMS to standard Bioelectrical Impedance Analysis (BIA) found that REMS provided accurate body fat percentage and metabolic rate estimates that did not differ significantly from BIA measurements — suggesting REMS can be an effective alternative for body composition assessment.

This makes REMS/Echolight a multidimensional tool, giving both bone health and overall body composition data from the same non-radiation scan — valuable for personalized care planning.

Book a Bone Density Assessment in Calgary

BioStrong Avenida is equipped with the Echolight REMS bone density scanner.

If you’d like to:

• Establish a baseline
• Understand your T-score
• Assess osteopenia or osteoporosis risk
• Track your progress safely
• Learn about your body composition

📞 Call 403.978.9780 🌐 Book a scan online!

Our team is happy to guide you through your options.

Frequently Asked Questions

Is REMS as accurate as DEXA?

Studies suggest comparable accuracy for lumbar spine and femoral neck BMD measurements.

Can I switch between DEXA and REMS for follow-up?

No. For accurate longitudinal tracking, you must use the same technology consistently.

Is REMS covered by insurance?

Coverage varies. Contact us for details regarding your provider.