Digital mammography. ROC studies of the effects of pixel size and unsharp-mask filtering on the detection of subtle microcalcifications

We investigated the spatial resolution requirement and the effect of unsharp-mask filtering on the detectability of subtle microcalcifications in digital mammography. Digital images were obtained by digitizing conventional screen-film mammograms with a 0.1 X 0.1 mm2 pixel size, processed with unsharp masking, and then reconstituted on film with a Fuji image processing/simulation system (Fuji Photo Film Co., Tokyo, Japan). Twenty normal cases and 12 cases with subtle microcalcifications were included. Observer performance experiments were conducted to assess the detectability of subtle microcalcifications in the conventional, the unprocessed digital, and the unsharp-masked mammograms. The observer response data were evaluated using receiver operating characteristic (ROC) and LROC (ROC with localization) analyses. Our results indicate that digital mammograms obtained with 0.1 X 0.1 mm2 pixels provide lower detectability than the conventional screen-film mammograms. The detectability of microcalcifications in the digital mammograms is improved by unsharp-mask filtering; the processed mammograms still provide lower accuracy than the conventional mammograms, however, chiefly because of increased false-positive detection rates for the processed images at each subjective confidence level. Viewing unprocessed digital and unsharp-masked images in pairs resulted in approximately the same detectability as that obtained with the unsharp-masked images alone. However, this result may be influenced by the fact that the same limited viewing time was necessarily divided between the two images.     

Positive sign of the stenocardia syndrome as a criterion of myocardial ischemia during the treadmill test

Diagnostic validity of the criteria of myocardial ischemia in coronary patients exposed to the treadmill test is assessed. The risk of a false diagnosis of coronary insufficiency on the basis of the pain syndrome was 5 times as high as that of diagnosis based on ischemic electrocardiographic ST depression. In subjective assessment of walking tolerance, patients with severe angina were particularly prone to mistakes. Limitations of angina classifications by severity, based on subjective sensations of coronary patients, are considered.     

Morphological observations in skeletal muscle from patients with a mitochondrial myopathy

The regional distribution of the phenylalanine-sensitive ATP-sulphurylase in fetal calf brain coincides with demyelinated lesions observed in the central nervous systems of untreated PKU patients. This would be expected if this species of ATP-sulphurylase played a role in the pathogenesis of brain dysfunction in the untreated or poorly controlled phenylketonuria patient.     

Role of immediate versus delayed nephrectomy for failed renal transplants

The role of timing of transplant nephrectomy after renal transplantation has not been well defined. This report compares the morbidity, mortality, and hospitalization costs of 37 patients undergoing transplant nephrectomy within 14 days after graft failure and return to dialysis, with 31 patients undergoing delayed transplant nephrectomy (less than 14 days after graft failure and return to dialysis). This analysis revealed that there were no significant (P greater than .05) differences in patient morbidity and mortality between these groups. There was, however, a substantial increase (P less than .05) in the cost of hospitalization in the delayed nephrectomy group. For this reason, we recommend early nephrectomy after renal transplant failure in order to minimize the cost of health care for these patients undergoing failed cadaver donor transplant nephrectomy.     

303. Orientierungshilfen in der diagnostischen und operativen Schulterarthroskopie

Zusammenfassung Zu Beginn des Videofilms wird die Problematik der Rectumcarcinomdiagnostik mit genauer Bestimmung der Wandinfiltration dargestellt. Als zusätzliches diagnostisches Verfahren wird sodann die endorectale Sonographie und deren Prinzip erläutert. An einer Falldarstellung (Patient mit ulcerierendem Rectumcarcinom und Rectumpolypen) wird die sonographische Methode im Vergleich mit der Rectoskopie und weiteren bildgebenden Verfahren sowie dem Operationspräparat und dem histologischen Schnitt verglichen. Eine weitere Anwendungsmöglichkeit der endorectalen Sonographie liegt in der Verlaufskontrolle operierter Patienten mit Rectumcarcinom. Dies wird an einer weiteren Falldarstellune erläutert.     

Renal Aspergilloma--A Case Illustrating the Problems of Medical Therapy

The second documented case of renal aspergilloma due to Aspergillusflavus is presented. The merits of the medical therapy thatfailed are discussed. Pathological examination showed a nidusof aspergillus around suture material persisting from a pyelolithotomyoperation 2 years before in India. We argue that this was thereason for the failure of the medical therapy. This is the firstcase of its kind reported.     

Traumatology of the alar ligaments

A postmortem study of craniocerebral traumas of varying severity was done to determine the pattern of injury of the alar ligaments. It was found that in the entire group of patients (n = 30) the alar ligaments were ruptured or suffused with blood 11 times. No close relationship was found between the massive nature of the cranial trauma and the severity of the injury of the alar ligaments. In some cases the alar ligaments were not at all involved even though the skull had suffered extensive osseous lesions, whereas on the other hand the ligaments were injured even though only soft parts had been involved (e.g., haematoma or dehiscent wounds of the scalp). Ruptures of the alar ligaments were typically involved in extended ruptures of the ligamentous apparatus (see Figure 6a involving the ligamentum apicis dentis, ligamentum transversum atlantis, m.atlanto-occipitalis anterior, m.tectoria, m.atlanto-axialis anterior et posterior). In some cases the pattern of injury of the alar ligaments was found to be decisive in enabling reconstruction of the course of the accident. Damage to the alar ligaments near the dens axis represent rotation injuries. On the other hand, insertion tears out of the condyli occipitales must be related to a lateral thrust tendency in indirect fracture of the skull (bursting fracture). Within this overall framework a new mechanism of fracture of the condylus occipitalis is described. As a matter of principle, the alar ligaments can become involved in consequence of rotation, traction and compression of the cranium.