Dual-Energy X-Ray Absorptiometry (DEXA) Scan Versus Computed Tomography for Bone Density Assessment

Area of Science:

• Radiology
• Osteoporosis Research
• Medical Imaging Analysis

Background:

• Osteoporosis causes significant physical, psychological, social, and economic losses, necessitating early diagnosis for fracture prevention.
• Dual-Energy X-ray Absorptiometry (DEXA) is the standard for bone mineral density (BMD) assessment but has limitations.
• Advancements in CT technology allow for Hounsfield Unit (HU) value analysis, offering potential for opportunistic osteoporosis screening.

Purpose of the Study:

• To investigate the correlation between BMD and T-scores from DEXA and HU values from CT scans of L1-4 vertebrae.
• To establish reference CT values for opportunistic osteoporosis screening.
• To evaluate CT as a supplementary tool for osteoporosis assessment, potentially reducing radiation exposure and the need for separate DEXA scans.

Main Methods:

• A retrospective study analyzed data from 78 female patients who underwent both DEXA and CT scans within a two-year interval.
• Pearson correlation coefficient was used to analyze the relationship between HU values, age, DEXA-measured BMD, and T-scores.
• HU values from L1-4 vertebrae CT images were correlated with DEXA BMD and T-scores.

Main Results:

• A significant positive correlation was found between HU values and DEXA-measured BMD (r² range: 0.581-0.653) and T-scores (r² range: 0.544-0.611) for L1-4 vertebrae (p<0.001).
• Mean HU values decreased with age, showing a range from 202.17 HU in the fifth decade to 71 HU in the ninth decade.
• Distinct mean HU values were observed across normal (174.05 HU), osteopenia (120.45 HU), and osteoporosis (115 HU) groups, with significant differences between them.

Conclusions:

• CT-derived HU values demonstrate a strong positive correlation with DEXA-measured BMD and T-scores, validating CT's utility in osteoporosis assessment.
• Routine CT scans, such as those of the abdomen or lumbar spine, can provide valuable information for opportunistic osteoporosis screening.
• CT offers a reproducible, accessible, and reliable method for opportunistic osteoporosis screening, potentially reducing the need for additional specialized scans and associated radiation exposure.