Trabecular bone mineral density measurement using thoracic and lumbar quantitative computed tomography.

Area of Science:

• Radiology
• Osteoporosis Research
• Quantitative CT

Background:

• Assessing bone mineral density (BMD) is crucial for osteoporosis diagnosis.
• Current methods often require separate scans, increasing patient burden and radiation dose.
• Cardiac CT imaging presents an opportunity to assess thoracic spine BMD non-invasively.

Purpose of the Study:

• To evaluate the agreement between bone mineral density (BMD) in lumbar (L) and individual thoracic (T) vertebrae.
• To identify a standard thoracic spine level for BMD assessment using cardiac computed tomography (CT) images.

Main Methods:

• Simultaneous chest and abdomen CT scans were performed on 300 subjects.
• Vertebral BMD was measured using QCT 5000 and NVivo systems with a calibration phantom (T1-L5).
• Associations between lumbar (L1-L3) and thoracic BMD (3T) were evaluated.

Main Results:

• BMD values decreased from T1 to L3, then increased in L4 and L5.
• 3T BMD was significantly higher than L1-L3 BMD in both genders (P < .001).
• High correlations were found between 3T and L1-L3 BMD (r=0.91-0.93), and between L1-L3 and individual thoracic vertebrae (r=0.62-0.98).

Conclusions:

• Thoracic spine BMD (3T) is highly correlated with lumbar spine BMD (L1-L3).
• Thoracic BMD can be measured during cardiac and lung CT scans without additional patient burden or radiation.
• This reproducible method is valuable for large cohort studies on osteoporosis prevalence and progression.