A new implementation of digital X-ray radiogrammetry and reference curves of four indices of cortical bone for healthy European adults.

UNLABELLED: Digital X-ray radiogrammetry performs measurements on a hand radiograph in digital form. We present an improved implementation of the method and provide reference curves for four indices for the amount of bone. We collected 1662 hand radiographs of healthy subjects of age 9-100 years. PURPOSE: The digital X-ray radiogrammetry (DXR) method has been shown to be efficient for diagnosis of osteoporosis and for assessment of progression of rheumatoid arthritis. The aim of this work is to present a new DXR implementation and reference curves of four indices of cortical bone and to compare their relative SDs in healthy subjects at fixed age and gender. MATERIALS AND METHODS: A total of 1662 hand radiographs of healthy subjects of age 9-100 years were collected in Jena in 2001-2005. We also used a longitudinal study of 116 Danish children born in 1952 with on average 11 images taken over the age range 7 to 40 years. The new DXR method reconstructs the whole metacarpal contour so that the metacarpal lengths can be measured and used in two of the indices. The new DXR method automatically validates 97 % of the images and is implemented as a local server for PACS users. RESULTS: The Danish bone health index (BHI) data are consistent with the Jena data and also with the published BHI reference for healthy children. BHI is found to have smaller relative SD than the other three indices in the Jena cohort over the age range 20-80 years. CONCLUSION: The new DXR method is an extension of the existing BoneXpert method for children, which allows patients to be followed from childhood into adulthood with the same method. By making all four indices of cortical bone available within the same medical device, it becomes possible to decide which index has the best relation to fracture risk in future studies.

Subclassification of anencephalic human fetuses according to morphology of the posterior cranial fossa.

Anencephaly is a designation for congenital absence of the cranial vault with cerebral hemispheres completely missing or decreased to small masses attached to the base of the skull. The etiology is unknown. Whether the bony tissue or soft brain tissue is a primary factor is also unknown. The present study has focused on the posterior cranial fossa in anencephaly. The goal is to determine whether differences in the posterior cranial fossa could provide a basis for subclassification of anencephalic fetal skeletons. Twenty-three human anencephalic fetuses, at gestational ages 13 to 22 weeks, were studied. Radiologic and cephalometric analyses, including measurements of bone sizes and different angles, were performed. Permission for autopsy of the central nervous system was not available. For comparison of anencephalic findings with normal conditions, standards from a recent publication were used. Foot length served as a parameter for age comparison. The study showed 2 morphologic types of the posterior cranial fossa. One type had a fossa cranial morphology close to normal morphology, whereas the other had a malformed and much smaller posterior cranial fossa. The latter condition was presumed to be due to a primary error in chondral and cranial development. The current skeletal subgrouping might be essential for clinicians' or pathologists' future assessment of the autopsy results. The skeletal subgrouping should, if possible, be associated with karyotyping and analysis of the central nervous system. The goal is to distinguish between congenital conditions resulting in anencephaly and acquired conditions resulting in anencephaly.

Third molar agenesis in Down syndrome.

The frequency, gender, and maxillary/mandibular occurrences of third molar agenesis have been studied in a Danish population of Down syndrome individuals (39 F and 31 M). The study was based on radiological examination and compared with 2 control groups of normal Caucasian populations. We found that the occurrence of third molar agenesis in Down syndrome individuals was around 4 times greater than in a normal population and higher than in corresponding previous studies. The agenesis occurred more often in the maxilla than in the mandible, and the frequency was not significantly higher in females than in males. The present study stresses the importance of focusing on the dental germs in the phenotypic discussion, as different genes are involved in tooth formation. The absence of teeth can contribute to an understanding of the interaction between genotype and phenotype.