Scan Mode
This panel shows the results of the same patient scanned in both fast and fast array mode. Using the 95% confidence interval for the lumbar spine, there is not a significant difference in the L1-L4 bone mineral density.
A second example of a patient scanned in both fast array and array mode. There is not a significant difference in L1-L4 bone mineral density between the two scans.
Case Description:
There are various scanning modes, which refer to the rapidity of the scan and the amount of radiation. In Hologic the scan modes are array, fast array, express, and high definition for the spine and hip. The forearm scan has only the array mode available. In Hologic, the results are generally the same for different scanning models until the TH value is >10 (thick patients). For large patients, the extra radiation from the array mode is useful, compared to the fast mode. It is recommended that patients be scanned in the same mode on a follow-up scan.
Credit:
Sarah L Morgan, MD, RD, CCD, The University of Alabama at Birmingham
References:
• Bandirali M et al. In vivo differences among scan modes in bone mineral density measurement at dual-energy X-ray absorptiometry. Radiol Med. 2014 April 119(4): 257-60.