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MR Vol.10 No.4 indexに戻る
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MODERN RHEUMATOLOGY
Vol.10 No.4 |
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Quantification of bone volume on radiographs
using NIH Image |
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| R. Nagamine1, Y. Hanada1, M. Kondo1, S. Fukumoto1,
T. Shuto1, Y. Nakashima1, G. Hirata1, A. Katayama 1, Y. Iwamoto1 |
| (1)Department of Orthopaedic Surgery, Postgraduate
School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku,
Fukuoka, Japan |
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| Abstract |
| Abstract We attempted to quantify periarticular
bone atrophy from radiographs of the proximal phalanx in patients
with rheumatoid arthritis (RA) by means of the National Institutes
of Health (NIH) Image computer program. The degree of brightness
or darkness in four squares, each 20 2 20 pixels, in the right third
proximal phalanx was measured using NIH Image, and the mean value
of the 400 pixels was defined as the brightness/darkness index (BDI).
The BDI was used to express bone volume. The BDI value was set at
zero for an area of complete darkness and at 255 for an area of maximum
brightness. The mean coefficient of variation in our hospital was
2.28%. The BDI was measured in 54 RA patients and 146 normal volunteers.
The mean BDI at the midpoint of the diaphysis was 100 in RA patients
and 176 in normal volunteers, while at the medial side of the proximal
end it was 75 and 145, respectively. The difference between normal
volunteers and RA patients was greatest in younger people. In some
young RA patients, the BDI was significantly low at the medial side
of the proximal end, clearly demonstrating periarticular bone atrophy.
Periarticular bone atrophy can be quantified using the NIH Image
computer program. |
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| Key words |
| Key words Radiograph ・ Rheumatoid arthritis
・ Bone volume ・ NIH Image ・ Computer |
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