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The shape of the proximal femur has been demonstrated to be important in the occurrence of fractures of the femoral neck. Unfortunately, multiple geometric measurements frequently used to describe this shape are highly correlated. A new method, active shape modeling (ASM) has been developed to quantify the morphology of the femur. This describes the shape in terms of orthogonal modes of variation that, consequently, are all independent. To test this method, digitized standard pelvic radiographs were obtained from 26 women who had suffered a hip fracture and compared with images from 24 age-matched controls with no fracture. All subjects also had their bone mineral density (BMD) measured at five sites using dual-energy X-ray absorptiometry. An ASM was developed and principal components analysis used to identify the modes which best described the shape. Discriminant analysis was used to determine which variable, or combination of variables, was best able to discriminate between the groups. ASM alone correctly identified 74% of the individuals and placed them in the appropriate group. Only one of the BMD values (Ward's triangle) achieved a higher value (82%). A combination of Ward's triangle BMD and ASM improved the accuracy to 90%. Geometric variables used in this study were weaker, correctly classifying less than 60% of the study group. Logistic regression showed that after adjustment for age, body mass index, and BMD, the ASM data was still independently associated with hip fracture (odds ratio (OR)=1.83, 95% confidence interval 1.08 to 3.11). The odds ratio was calculated relative to a 10% increase in the probability of belonging to the fracture group. Though these initial results were obtained from a limited data set, this study shows that ASM may be a powerful method to help identify individuals at risk of a hip fracture in the future.

In mammography, national breast screening programmes have lead to a large increase in the number of mammograms needing to be studied by radiologists. Lesion indicators can be pointlike as in microcalcifications or extended as in stellate (spiculate) lesions or regular masses. Texture analysis has been proposed as a promising method for studying radiographic images in relation to the quantitation of extended objects. Filters have been designed, which may be used to segment or classify an image using textural features, and these have been reported as being of value in automatic mammographic glandular tissue classification. The work reported here suggests the incorporation of additional steps of image processing in an attempt to improve the performance of these filters in the quantitation of lesions. By deriving approximate outlines, which are used to identify suspicious regions, the investigation illustrates the properties of one of the filters. After applying the method to a small prediagnosed database of stellate lesions and regular masses, the results show that the filter is able to outline the malignant masses in all cases presented. The erroneous areas extracted are small for the initial part of the work, which deals with 256 x 256 pixel image extracts, though slightly larger in some cases when the whole mammogram is considered. Simple methods for the removal of these artefacts are proposed. For each non-suspicious case studied, the sum of any false positive areas is statistically insignificant when compared with the regions correctly outlined in the prediagnosed instances.

In recent years, teleultrasound has emerged as a potentially effective method of provision of ultrasound services to remote areas of the community. Transmission of teleultrasound, however, requires a high degree of compression when utilizing the relatively low bandwidth ISDN connections available within the UK. The actual amount of compression occurring varies both with the connection and the image content, often on a frame to frame basis. For this reason, traditional measurements of image quality using test tools are ineffective. Most studies to date have assessed equipment performance by testing diagnostic performance. Although this is the most important method of assessing the results of image degradation, few studies have attempted to perform physical measurements of degradation. The aims of this study were to measure the amount of degradation within a teleultrasound system and, using a number of methods, to ascertain the most useful indicators of loss of image quality. Groups of successive abdominal ultrasound images were captured and digitized both before and after degradation via an ISDN6 teleultrasound system. Normalized mean squared error (NMSE), pixel histograms, line and surface plots, Fourier spectra and contrast measurements were carried out on regions of interest in both sets of images. The NMSE was most sensitive to degradation, with alterations in the NMSE value depending on image content and degree of degradation. Fourier analysis was also indicative, showing consistent changes in high frequency content again varying with image content.

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