Wolfgang Gowin

Recent developments in DXA. Quality of new DXA/MXA-devices for densitometry and morphometry

The introduction of new devices demands the assessment of their capabilities in established terms. The accuracy, reproducibility and spatial resolution of in vitro (phantom) osteodensitometric and morphometric measurements of QDR 2000 Plus and EXPERT are presented. Design details of these DXA/MXA-devices are listed and discussed in combination with the data acquired in the test measurements and calculations. The image quality will improve with further software developments. The long-term reproducibility and in vivo reliability remains to be evaluated.

Prävalenz der vertebralen Wirbelkörperdeformationen bei Frauen und Männern in Deutschland

BACKGROUND The prevalence of radiographically defined vertebral deformities, as a marker of vertebral osteoporosis, was calculated in a population based cross-sectional survey in Germany. METHOD Lateral spine X-rays were taken according to a standardized protocol and evaluated centrally. Three thousand nine hundred and eighty subjects (2064 male and 1916 female) aged 50 to 79 years, have been examined in 8 German centers. RESULTS Based on McCloskeys method of deformity definition the age-standardized mean prevalence of vertebral deformities in Germany was 10.2% for males and 10.5% for females. Based on the definition by Melton/Eastell a significant higher prevalence was calculated (males 17.8%, females 18.7%). The prevalence increased with age in both sexes with a steeper increase in females. There was no difference in East and West German populations. There were substantial variations between the centers regarding the prevalence of deformities in females and males.Summary□Background: The prevalence of radiographically defined vertebral deformities, as a marker of vertebral osteoporosis, was calculated in a population based cross-sectional survey in Germany.□Method: Lateral spine X-rays were taken according to a standardized protocol and evaluated centrally. Three thousand nine hundred and eighty subjects (2064 male and 1916 female) aged 50 to 79 years, have been examined in 8 German centers.□Results: Based on McCloskey’s method of deformity definition the age-standardized mean prevalence of vertebral deformities in Germany was 10.2% for males and 10.5% for females. Based on the definition by Melton/Eastell as significant higher prevalence was calculated (males 17.8%, females 18.7%). The prevalence increased with age in both sexes with a steeper increase in females. There was no difference in East and West German populations. There were substantial variations between the centers regarding the prevalence of deformities in females and males.

Bone densitometry : applications in sports-medicine

Physical exercise and sports increase muscular mass and the remodelling process of bones. The increment of bone depends on the type and the quality of sport. Short-term high-performance activities such as sprint, tennis, fencing lead to increased bone mineral density as well as weight lifting or heavy athletics. Swimming, bicycling, walking are associated with good musculature conditioning without an increase of bone mass. The effects on the bone by performing endurance activities are controversially discussed. Excessive sport leads to an increase of fatigue fractures. Low bone mass may result from hormonal disregulation in female athletes.

Morphometrische Analyse von Röntgenbildern der Wirbelsäule zur Diagnose einer osteoporotischen Fraktur

The European Vertebral Osteoporosis Study (EVOS) is one of the largest studies to investigate the prevalence of osteoporosis related vertebral fractures in a population based cross-sectional study. One of the main tasks was to create standards and logistics to obtain uniform and comparable radiographs in all 36 European centers. Furthermore the central reading of the X-rays and the morphometry of the vertebral bodies were 2 important challenges. This paper describes the standardized patient positioning and making of the radiographs as well as their morphometry, reading, and evaluation.Summary□ The European Vertebral Osteoporosis Study (EVOS) is one of the largest studies to investigate the prevalence of osteoporosis related vertebral fractures in a population based cross-sectional study. One of the main tasks was to create standards and logistics to obtain uniform and comparable radiographs in all 36 European centers. Furthermore the central rading of the X-rays and the morphometry of the vertebral bodies were 2 important challenges. This paper describes the standardized patient positioning and making of the radiographs as well as their morphometry, reading, and evaluation.ZusammenfassungIn der gesamten EVOPS- bzw. EPOS-Studie wurden über 50 000 Röntgenbilder ausgewertet. Zur Durchführung der zentralen Auswertung wurde die Logistik der Aufnahmetechnik, der Patientenlagerung, der geometrischen Vermessung, der digitalen Speicherung und der Datenverarbeitung erarbeitet. Die Befundung der Röntgenbilder und deren geometrische Vermessung erfolgte durch Radiologen older durch speziell dafür ausgebildete Ärzte oder Ärztinnen. Die geometrischen Daten wurden statistisch mit unterschiedlichen Verfahren und Frakturdefinitionen (nach Melton/Eastell, McCloskey/Kanis, Felsenberg) ausgewertet. Gleichzeitig wurde ein Algorithmus zur automatisierten geometrischen Vermessung von Röntgenbildern der Brust- und Lendenwirbelsäule entwickelt.

A statistical method to minimize magnification errors in serial vertebral radiographs

Abstract: Incident vertebral deformities are commonly defined by observed changes in height between measurements on two consecutive radiographs. However, conventional radiographs are subject to magnification, and this magnification may differ between films, leading to artifactual changes in height. In order to minimize this effect, it is common practice to record the spine–film and film–focus distances, and from this to calculate a magnification factor for each film. We present a simple statistical method for correcting for differences in magnification between two films if the spine–film and film–focus distances are unknown. This method is shown to reduce the variance of the magnification differences in vertebral heights by 14%, considerably more than is possible using the spine–film distance. Using the statistical method, the number of vertebrae that showed not only a reduction in one or more height of 15%, but were also judged clinically to be free from any incident deformity by an expert radiologist, was reduced from 100 to 46. The number showing a reduction of 20% that were judged fracture-free was reduced from 15 to 9. In the subset of subjects for whom the spine–film distance was known, the reduction in false positives was similar, whichever method was used to correct for magnification. There was no difference in the number of confirmed incident fractures detected when magnification correction by either method was employed. It is concluded that correcting for magnification differences using the statistical method outlined here reduces the number of false positive deformities very substantially and by a similar extent as correcting the magnification using reliable, measured spine–film and film–focus distances. A further advantage of this method is that it can be used retrospectively.

Acronyms in Osteodensitometry

Abstract The refinement of technologies and the development of new techniques based on osteodensitometry requires a communication basis understandable to both the referring and the providing physician. The terminology and the acronyms of bone densitometry measurements should follow internationally accepted conventionality. The correct utilization of the terminology is advocated and will reduce common entanglement.

Bones And Nonlinear Dynamics — The Quantification Of Architecture

In order to quantify the internal architecture of a bone in a holistic manner based on radiological images, the methodology of nonlinear dynamics was applied. Image processing algorithms, an expansion of symbolic dynamics, and five measures of complexity were introduced to quantify the trabecular part of human lumbar vertebral bodies. Healthy vertebral bones have a complex and ordered architecture with a high degree of spatiodynamics. Pathology changes the architecture significantly and can be quantified by measures of complexity.

The osteoporotic vertebral fracture/deformity and its differential diagnosis

BODIES AND ITS CHANGES IN OSTEOPOROSIS W. Gowin, L. Welzing, D. Felsenberg, C. M~ller, F. Alenfeld, E. DieSel, J. Dequeker 2 on behalf of the Biomed Group, University Hospital Benjamin Franklin, Dept. of Radiology, Osteoporosis Research Group, Berlin, Germany, 2University Hospital Pellenberg, Rheumatology Unit, Pellenberg, Belgium The purpose of the study was to evaluate the distribution of trabaculae within vertebral bodies. Normal vertebrae were compared with osteoporotic vertebrae. 50 L3 cadaver vertebrae (Biomed i) were evaluated. Axial slices were obtained by computer tomography. The slices were reconstructed in the coronal and sagital planes. The bone volume fraction (BV/TV) was calculated in all three planes and compared with the BMD. A subjective qualitative assessment of x-ray absorption of the standardized images concluded the evaluation. The highest BV/TV was found in the dorsal, the lowest in the ventral portion of the vertebrae. This distribution pattern remains the same in osteoporotic vertebrae. In osteoporosis, the BV/TV decreases in all portions of the vertebrae, mostly in the ventral and mid-coronal region. The least loss of bone was found in the dorsal region. The pattern of trabaculae distribution and its reduction in osteoporosis is an implication for the architectural stability of the vertebral body.