[Normal values of sacroiliac index according to gender and age].
Using quantitative sacroiliac joint scintigraphy for identifying patients with active sacroiliitis the diagnosis is relied on the abnormally high values of sacroiliac (SI) index. However, the normal range of SI index and the threshold for detecting the disease are still under discussion in the literature.


OBJECTIVE
The aim of the study was to determine SI indices in a sample representing normal population for establishing normal values and the optimal threshold for our laboratory. The author investigated the effect of age and gender on SI indices.


METHODS
SI indices in 740 nonarthritic control subjects were determined by standard method. Data were analyzed separately for males and females in different age groups (in 10-year intervals).


RESULTS
Mean SI index derived for the control groups showed significant negative linear correlation with age and statistically significant differences between genders. The intra-individual difference between left and right SI joint was similar in each groups.


CONCLUSIONS
The ranges of normal SI indices are different for males and females and for different age groups. For diagnosing bilateral sacroiliitis, the upper limit of 99% confidence interval is recommended as optimal cut-off value. The data between upper limits of 95% and 99% confidence intervals should be interpreted as uncertain category. The detection of unilateral sacroiliitis is possible even by the increased rate in difference between left and right SI index. The anatomic variability of sacrum should be taken into account during quantitative sacroiliac scintigraphy.
Bajner
Agnes
A
Vas Megyei Markusovszky Kórház Nonprofit Zrt., Nukleáris Medicina Osztály, Szombathely. bajner.agnes@markusovszky.hu
D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging; D001847:Bone Diseases / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012016:Reference Values; D012446:Sacroiliac Joint / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology; D012727:Sex Characteristics; D012737:Sex Factors