BONE-DENSITY DETERMINATION OF MOOSE SKELETAL REMAINS FROM ISLE-ROYALE-NATIONAL-PARK USING DIGITAL IMAGE-ENHANCEMENT AND QUANTITATIVE COMPUTED-TOMOGRAPHY (QCT)

As part of an investigation of prey vulnerability in Isle Royale Natio nal Park, MI, digital image processing techniques were used to enhance original quantitative computed tomography (QCT) film products to deta il the processes of bone resorption and reformation in skeletal remain s of moose (Alces alces). Integration of these two allied imaging tech nologies allowed analyses of pixels representing fractions of millimet res of bone. Using regression analysis, linear conversions from the pi xel digital numbers (DN) to QCT Hounsfield units (HU) to actual bone m ineral density (BMD) values were calculated (r(2)=0.99), and a scale o f pixels per millimetre or bone was determined. The colour-enhanced im age revealed quantifiable patterns of density, porosity and asymmetry. In addition, the procedure provided a quick but consistent methodolog y for evaluating numerous scans. Combining the limited use of a high-d emand and expensive medical QCT scanner with a lower cost, readily ava ilable digital image processing and analysis system provides a techniq ue for researchers to investigate the bone integrity of individual ani mals and populations. This method of evaluating bone density has impli cations for use in determining differential skeletal part-preservation in archaeofaunal studies. (C) 1997 by John Wiley & Sons, Ltd.