Romosozumab induces increases in bone mineral density (BMD), likely most pronounced in the trabecular compartment. Dual-energy X-ray absorptiometry (DXA) areal BMD may underestimate compartment-specific responses. 3D Shaper estimates trabecular volumetric BMD, cortical surface BMD, and integral measures from standard DXA. Changes in these parameters following treatment remains incompletely characterised.  In 68 patients aged >50 years (mean 71.5) treated with romosozumab for 1-year, bilateral hip DXA scans (GE-Lunar iDXA) were performed at commencement and completion of treatment. Changes in mean total proximal femoral BMD (TPF-aBMD; g/cm²) were compared to 3D Shaper parameters: trabecular vBMD (Tr-vBMD; mg/cm³), cortical surface BMD (CsBMD; mg/cm²), cortical volumetric BMD (CvBMD, mg/cm3), and integral vBMD (IT-vBMD; mg/cm³).  Mean scan interval was 1.19 years. TPF-aBMD increased in 48/68 patients (71%); mean increase of +1.48%;  p<0.001. Tr-vBMD increased in 38/68 patients (56%); mean increase of +2.56%; p<0.01. The mean percentage increase in Tr-vBMD exceeded that of TPF-aBMD (difference +1.08%; p<0.05 .  CsBMD demonstrated a smaller mean percentage increase (+1.11%), while IT-vBMD showed a mean increase similar to TPF-aBMD (+1.43%), with no significant difference between the two measures.  CvBMD demonstrated smaller changes than TPF-aBMD (mean difference −0.83%, p=0.06).  Concordant changes in TPF-aBMD and Tr-vBMD were observed in 52/68 patients (76.5%), (Cohen’s κ = 0.51, p<0.001, Figure 1). Discordant responses occurred in 16/68 patients (23.5%), including 13 (19.1%) with increasing TPF-aBMD but declining Tr-vBMD, and 3 (4.4%) with declining TPF-aBMD but increasing Tr-vBMD. The distribution of individual differences (Tr-vBMD − TPF-aBMD) showed a positive mean shift, indicating greater trabecular response (Figure 2).  In romosozumab treated patients, TPF-aBMD demonstrated the most consistent increase. 3D Shaper-derived Tr-vBMD showed larger relative gains but greater variability, suggesting a stronger trabecular response, albeit with increased measurement variability. The smaller CsBMD change suggests a more modest cortical response to romosozumab.  3D Shaper Tr-vBMD may provide greater sensitivity to romosozumab treatment-related change, but with reduced consistency compared to TPF-aBMD. These findings highlight the potential value, and limitations, of compartmental bone assessment derived from DXA. Tr-vBMD may be more sensitive in capturing an anabolic response, while TPF-aBMD remains the most stable indicator of overall treatment effect.