Subtraction radiography and computer assisted densitometric analyses of standardized radiographs

Abstract

A standardized radiographic series of incrementally increasing alveolar crestal defects in skulls were subjected to analyses by subtraction radiography and computer assisted quantitative densitometric analysis. Subjects were able to detect change using subtraction radiography in alveolar bone defects with bone loss in the range of 1–5 percent as measured by 125I absorptiometry. Quantitative densitometric analyses utilizing radiographic pairs adjusted for differences in contrast (gamma corrected) can be used to follow longitudinal changes at a particular alveolar bone site. Such measurements correlate with change observed by 125I absorptiometry (r= 0.82–0.94).

Relationship between thromboelastography and long-term ischemic events as gauged by the response to clopidogrel in patients undergoing elective percutaneous coronary intervention

“…Multifactorial processes such as clinical, demographic, and hemostatic components influence ischemic events, and especially those after PCI (12). The current results suggested that only gender and the level of FBG differed significantly between ischemic and non-ischemic groups.…”

Radiometric Classification of Alveolar Bone Health

“…These studies have typically used digital subtraction radiography where image pairs taken at different times are superimposed and gray-scale differences computed (Grondahl et al, 1983(Grondahl et al, , 1987Ortman et al, 1985;Rethman et al, 1985;Hausmann et al, 1985Hausmann et al, , 1986Ruttimannet al, 1985Ruttimannet al, , 1986Okano etal., 1990;Webberet al, 1990). Changes in either the profile or radiodensity ofthe alveolar ridge can be accentuated with this technique when two conditions are satisfied: The images are exactly superimposed (which depends largely upon whether or not the exposure geometries have been controlled-that is, film and beam angulations), and the brightness levels of the films are matched to control for variations in film processing and x-ray source parameters (kVp and mA-seconds).…”

IMAGING SYSTEMS USED FOR DIAGNOSIS OF PERIODONTAL PATHOLOGY Part 2: Alternative Imaging Systems and Image Processing Methods

“…Konvansiyonel radyografi yöntemleriyle kemik dokusunda %30-60 oranında mineral kaybı olmaksızın radyografik olarak tanı koymak mümkün değilken, bu konuda yapılan çalışmalar çıkartma radyografisi kullanılarak %5'den daha az mineral kayıplarının %90 doğrulukta saptanabileceğini göstermektedir. 41 Çıkartma radyografisinin mineral değişikliklerin saptanmasındaki yüksek sensitivite oranı, interdental kemiği radyografik olarak sıklıkla inceleyip yorumlayan periodontoloji uzmanları için özellikle önem taşımaktadır. Örneğin, periodontal tedavi gören bir hastada alveoler kemik dokusunda oluşan kayıpların erken dönemde çıkartma radyografisi kullanılarak saptanması sayesinde geç kalınmadan müdahale edilmesi tedavinin başarı şansını artıracaktır.…”