Quantitative assessment of areal bone mineral density using multi-energy localizer radiographs from photon-counting detector CT

Abstract

Objective. To assess the accuracy and stability of areal bone-mineral-density (aBMD) measurements from multi-energy CT localizer radiographs acquired using photon-counting detector (PCD) CT. Approach. A European Spine Phantom (ESP) with hydroxyapatite (HA 0.5, 1.0 and 1.5 g cm -2 ) was scanned using clinical PCD-CT and a dual-energy x-ray absorptiometry (DXA) to compare aBMD values. To assess aBMD stability and reproducibility, PCD-localizers were acquired twice a day for one week, and once per week for five weeks. Multiple ESP anteroposterior thicknesses (18, 26, 34, and 40 cm) were achieved using a synthetic gel layer and scanned across eight tube current values for both 120 kV (15-120 mA) and 140 kV (10-80 mA). One-way analysis of variance was performed for statistical significance ( p In vivo performance of PCD-based aBMD was illustrated using a patient scan acquired at 140 kV and 40 mA, and lumbar aBMD values were compared with DXA. Main results. The ESP aBMD values from PCD-localizers demonstrated excellent day-to-day stability with a coefficient-of-variation ranging from 0.42% to 0.53%, with mean absolute percentage errors (MAPE) of less than 5% for all three vertebral bodies. The coefficient-of-variation for weekly scans ranged from 0.17% to 0.60%, again with MAPE below 5% for all three vertebral bodies. Across phantom sizes and tube currents, the MAPE values varied ranging from 1.84% to 13.78% for 120 kV, and 1.38%-9.11% for 140 kV. No significant difference was foun…