Reduced bone perfusion in proximal femur of subjects with decreased bone mineral density preferentially affects the femoral neck

Using dynamic contrast enhanced MR imaging, this study investigated perfusion of the proximal femur in subjects with normal BMD, low bone mass and osteoporosis. Study cohort comprised healthy elderly Hong Kong Chinese volunteers consisting of 107 males (74.4 ± 4.2 years, mean ± SD) and 135 females (73.9 ± 4.3 years). Right proximal femur BMD measurement by DXA and MR perfusion imaging (maximum enhancement, Emax and enhancement slope, Eslope) of the femoral head, neck, and proximal shaft were carried out within a one month interval. Normal BMD, low bone mass and osteoporotic subjects accounted for 46.7%, 44.9%, and 8.4% of males; and 32.6%, 43.7%, and 23.7% of females. Perfusion indices showed that femoral head perfusion was less perfused compared to the femoral shaft (Emax and Eslope indices of head region = 28% of shaft region). Compared with normal BMD subjects, Emax of femoral head, neck, and proximal femur shaft were reduced by 15 ± 5% (mean ± standard error); 40 ± 4%; 15 ± 5% respectively for low bone mass subjects, and 36 ± 4%; 50 ± 6%; 47 ± 6% respectively for osteoporotic subjects. Eslope of femoral head, neck, and proximal femur shaft were reduced by 17 ± 7%; 41 ± 5%; 4 ± 7% for low bone mass subjects and 50 ± 5%, 62 ± 5%, 34 ± 8% for osteoporotic subjects. In low bone mass and osteoporotic subjects there was a tendency for perfusion in the femoral neck to reduce to a greater degree relative to that in the femoral head and shaft.