Microradioscopic quantitation of periosteal resorption in secondary hyperparathyroidism of chronic renal failure

The feasibility of expressing periosteal resorption (PR) in hand bones quantitatively as a measure of skeletal involvement of hyperparathyroidism, was tested by measuring the length of surface irregularities in medial and lateral surfaces of the middle phlanges of digits II--IV in one hand. Measurements were made to 0.1 mm by microradioscopy of fine detail radiographs using a X 6 measuring magnifier. Randomly numbered unidentified radiographs from 60 normal subjects and 61 chronic renal failure patients were measured by Reader 1 twice at 4 weeks interval and by Reader 2 once. There was no significant systematic difference between the readers, or for Reader 1 over the 4 weeks interval. The intraobserver precision was estimated to be +/- 3.8 mm. Relative to the normal ranges (0--9 mm, mean 2.54) such precision is sufficient for diagnostic purposes and for comparison of groups. Diagnostically, this method was found to be more sensitive than the currently used gradient of PR (0 to 3+): definite abnormalities were detected in 30 of 61 patients by quantitative microradioscopy, and in 22 by the grading method. A further advantage is that the numerical expression is better suited for statistical analysis of data than the results by grading.