COMPARISON OF NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY WITH DUAL-PHOTON ABSORPTIOMETRY AND DUAL-ENERGY X-RAY ABSORPTIOMETRY IN THE MEASUREMENT OF THORACIC VERTEBRAL BONE-MINERAL DENSITY - COMPRESSIVE FORCE VERSUS BONE-MINERAL

P-31 nuclear magnetic resonance spectroscopy (NMRS) measurements were made on human, T2 and T3 vertebral bodies. The bone mineral content (B MC) of isolated vertebral bodies minus the posterior elements and disk s was measured using (1) NMRS on a 3.5 T, 85 mm bore GE Medical System s NT-150 superconducting spectrometer, (2) a Lunar Corporation DPX-L d ual-energy X-ray absorptiometry (DXA) scanner in an anterior-posterior (AP) orientation, (3) a Norland Corporation XR26 DXA scanner, also in an AP direction, and (4) a Norland Corporation model 2600 dual-photon absorptiometry (DPA) densitometer in both the AP and superior-inferio r (SI) directions. Vertebral body volumes were measured using a water displacement technique to determine volume bone mineral densities (VBM D). They were then compressed to failure using an electrohydraulic tes ting device, followed by ashing in a muffle furnace at 700-degrees-C f or 18 h. Correlations of BMC between NMRS and DPA, DXA and ashing were excellent (0.96 less-than-or-equal-to r less-than-or-equal-to 0.99); in a one-way analysis of variance (ANOVA) test, means were not statist ically different at a p level of 0.757. The correlations of VBMD betwe en NMRS and the other methods were not as good (0.83 less-than-or-equa l-to r less-than-or-equal-to 0.95); in a one-way ANOVA test, means wer e not statistically different at a p level of 0.089. BMC was a better predictor of ultimate compressive failure than VBMD for all six method s. For NMRS, the regression coefficient for BMC was r2 = 0.806, compar ed with r2 = 0.505 for VBMD. NMRS may prove an alternative to present methods of determing bone mineral.