1 All radiogrammetry methods measure the volume of bone tissue r

1. All radiogrammetry methods measure the volume of bone tissue rather than its mineral content. If mineralization is a constant, as is the case in healthy subjects, this is the same thing. But some disorders alter the degree of mineralization, and radiogrammetry is inPF-4708671 mw sensitive to this. Many would consider this to be a weakness of the radiogrammetric method—it

is sensitive to osteopenia, defined as a decrease in the amount of bone tissue, but insensitive to osteomalacia, i.e. a decrease in the mineral content of bone.   2. A limitation of all radiogrammetric methods performed on metacarpals is that they measure only cortical bone, and they measure at a site different buy Z-VAD-FMK from the most relevant sites of fractures, e.g. spine and hip. Notice, however, that the main reason for measuring bone mass in children is not to estimate fracture risk at specific sites but rather to assess the general bone mass accrual during childhood.   3. pQCT provides more detailed information on bone geometry than PBI. Notice, however, that the radiogrammetric method can also give specific information on bone length and inner and outer diameters.   4. In comparison with DEXA and pQCT, PBI has the advantage that it takes only a fraction of a second to record the image, so movement artefacts are not a problem.   5. The effective radiation dose

of MCC950 in vitro a hand X-ray is very small, 0.10–0.12 μSv for children of age 10–15 year, corresponding to less than 30 min of the background radiation [18]. The effective radiation dose for a spine DEXA for 10–15-year-old children is 7.1–5.0 μSv, if the appropriate paediatric software is used. [19]. This is about 50 times more than for a hand X-ray. The adult effective dose values of pQCT range from less than 1 μSv for a single slice to 25–50 μSv, depending on the system and technique used [20]. Thus, the radiation dose of PBI is much smaller than for the conventional methods.   6. If PBI is based

on an X-ray taken for the purpose of bone age determination, the PBI measurement is obtained at no extra radiation VAV2 dose or cost. PBI could be an efficient screening tool prior to the use of more elaborate bone densitometers, in particular in regions of the world where bone densitometers are not within easy reach.   Effect of image magnification MCI and ESI (and all other indices with a + b = 2) have the advantage of being scale-invariant, i.e. if the radiographic bone image is magnified, the index is unchanged. PBI is not scale-invariant. The standard geometry of bone age hand X-rays is a distance from the X-ray tube to the detector (film–focus distance) of 1 m and a distance from the centre of the metacarpals to the detector of 1.5 cm. The magnification is then 1.5%, and the PBI reference database presented here corresponds approximately to this geometry (the Erasmus study actually used a film–focus distance of 1.

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