Hologic Hip Global Region of Interest Incorrect

 

In this Hologic left proximal femur scan, the global hp region of interest is incorrect. The bottom line, which is the most important for analysis, is down > 10 pixels from the lesser trochanter The ischium has been painted out because part of the femoral neck box overlaps the ischium.

In this image, the bottom of the hip region of interest box has been corrected. Notice that the bone mineral density of the total hip is now less because less cortical bone is included. The ischium has been painted out because a portion of the femoral neck box overlaps the ischium.

Case Description:

On a Hologic hip scan, the bottom of the region of interest box should be 10 pixels below the lesser trochanter. The image on the left is incorrect because the bottom of the region of interest box is >10 pixels below the lesser trochanter. By lowering the bottom of the region of interest box, the bone mineral density is generally falsely elevated, because more cortical bone is included in the total hip region of interest. The analysis on the right is the corrected analysis.
It is important to step through the entire hip analysis. Auto analysis is typically correct less than 50% of the time. The upper, inner and outer edges are all set with a blue line that touches bone and the yellow line is 5 pixels out, which places the region of interest line. The bottom line is 10 pixels below the lesser trochanter.
In both analyses, notice that a portion of the femoral neck overlaps the ischium and the ischium has been painted out.

Credit:

Sarah L Morgan, MD, RD, CCD, The University of Alabama at Birmingham

References:

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