Opportunistic Bone Mineral Density Measurement Using Photon-Counting Detector CT Spectral Localizer Images: A...

Area of Science:

• Radiology and Imaging
• Bone Health and Osteoporosis
• Medical Physics

Background:

• Photon-counting detector (PCD) CT offers material decomposition capabilities, enabling bone mineral density (BMD) evaluation from spectral localizer images.
• Opportunistic osteoporosis screening is feasible using existing PCD CT localizer images during clinically indicated scans.

Purpose of the Study:

• To evaluate the utility of PCD CT spectral localizer images for opportunistic derivation of areal BMD (aBMD) and T-scores.
• To compare aBMD and T-scores derived from PCD CT localizer images against dual-energy x-ray absorptiometry (DEXA) as the reference standard.

Main Methods:

• Prospective study of patients undergoing lumbar spine CT with PCD CT, including spectral localizer images.
• Extraction of aBMD from DEXA reports and derivation of aBMD and T-scores from PCD CT spectral localizer images using material decomposition.
• Comparison of DEXA-derived and PCD CT-derived T-scores, analyzing correlations with age, time interval, BMI, and sex.

Main Results:

• 51 participants (31 women, 20 men; mean age 62) included.
• High concordance (Lin's CCC=0.90) between DEXA- and PCD CT-derived T-scores; no significant difference in mean T-scores (p=0.29).
• PCD CT-derived T-scores demonstrated 97% sensitivity and 91% NPV for detecting abnormal bone mass.

Conclusions:

• PCD CT spectral localizer images are clinically useful for deriving aBMD values and T-scores.
• T-scores from PCD CT spectral localizer images can serve as an opportunistic screening tool for low bone mass and osteoporosis.