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Biomedical subjects

M Langer

Publications and source records attributed to M Langer.

At least 37 records · Page 2Linked to original sources

[Rupture of the quadriceps tendon. Diagnosis and treatment of a rare injury].

Rupture of the quadriceps tendon is a rare knee injury. In most cases the tendon ruptures spontaneously without adequate trauma in patients older than 40 years with degenerative changes of the tendon. Suture repair is the only treatment option for acute complete, older ruptures and partial ruptures that do not heal after nonoperative treatment. The type of repair depends on the time of diagnosis and localisation of the rupture. The functional outcome depends on timely repair and early initiation of knee movement and strengthening therapy.

Humans↗

[Conventional thorax diagnostics in neonates and children].

Advances in neonatal medicine have led to an increasing number of premature infant patients and to an improved survival rate of these children. Chest X-rays of premature infants, newborns, and older children with respiratory difficulties provide information leading to diagnosis and help decide on further clinical management. Diagnostic findings and their appreciation by the radiologist require knowledge of the specific anatomy of the infant chest, and also of common diseases in early and later childhood, congenital or acquired. Radiologic findings in pediatric patients may differ significantly from those in adults. Close collaboration between the neonatologist and radiologist is essential for reaching the right diagnosis.

Child↗

Diagnostic value of MRI in comparison to scintigraphy, PET, MS-CT and PET/CT for the detection of metastases of bone.

The initial localization of metastases in the bone in patients with solid tumors has a relatively good prognosis in comparison with visceral metastasization. The early detection of bone marrow metastases allows for a rapid initiation of therapy and a subsequent reduction in the morbidity rate. Modern MRI is superior to the 30-year-old skeletal scintigraphy and bone marrow scintigraphy with respect to sensitivity, specificity, as well as the extent of osteal metastasis. MRI provides substantial, therapy-relevant additional information. MSCT plays an important role in the management of cancer patients in clinical routine and gives an excellent survey of the axial skeleton by demonstrating osteolytic and osteoblastic metastases. Extensive comparative studies of MRI with 18F-FDG-PET and 18F-fluoride-PET have not yet been carried out. Whole body MRI is a very promising new staging method for the oncological diagnosis of solid tumors and the detection of osteal metastases. The adoption of 18F-FDG-PET and 18F-fluoride-PET FDG as well as the side by side PET-CT image fusion and the two in one PET/CT examinations appears to be slightly less sensitive to whole body MRI in the detection of osteal metastases. Larger, prospective multicenter studies are necessary to establish these as new, promising methods for the detection of osteal metastases.

Bone Neoplasms↗

Serial high-resolution computed tomography imaging in patients with Wegener granulomatosis: differentiation between active inflammatory and chronic fibrotic lesions.

PURPOSE: To evaluate pulmonary pathologies in Wegener granulomatosis with sequential computed tomography (CT) in order to differentiate active inflammatory lesions from chronic fibrotic lesions. MATERIAL AND METHODS: Serial CT findings in 38 patients with Wegener granulomatosis were retrospectively analyzed (mean follow-up period, 21 months). The presence, extension, and distribution of the following findings were evaluated with CT: parenchymal nodules, masses, ground-glass attenuation, airspace consolidation, bronchial wall-thickening, bronchiectasis, linear areas of attenuation, pleural irregularities, pleural effusions, hilar and mediastinal lymphadenopathy. RESULTS: Observed in 92% of patients, nodules were the most common CT pathology. Areas of ground-glass attenuation, consolidation, masses of linear attenuation, and tracheal/bronchial wall-thickening were detected in 24%, 26%, 32%, 39%, and 68% of patients. At follow-up, the clearance of lesions was most consistent for areas of ground-glass attenuation (89%), masses (87%), and cavitated nodules (85%). In the follow-up scan, 58% of all nodules, 47% of pulmonary consolidations, and 66% of bronchial wall-thickening were completely resolved. Areas of bronchiectasis and septal/non-septal lines remained stable in 70% and 71% of patients. CONCLUSION: The majority of the lesions decreased or resolved completely with or without areas of linear attenuation. Ground-glass attenuation, cavitated nodules and masses appear to represent active inflammatory lesions. In most probability, areas of bronchiectasis and septal/non-septal lines more often represent chronic fibrotic changes rather than active inflammatory changes. In combination with clinical evaluation and bronchoscopy, CT assists in the assessment of disease activity.

Adult↗

[Whole-body MRI in comparison to skeletal scintigraphy for detection of skeletal metastases in patients with solid tumors].

PURPOSE: The aim of this study was to compare the diagnostic efficacy of whole-body magnetic resonance imaging (WB-MRI) as a new and rapid examination technique with skeletal scintigraphy for detection of skeletal metastases from solid tumors. MATERIAL AND METHODS: In 129 patients with solid malignant tumors, WB-MRI was performed for individual comparison with skeletal scintigraphy. Examinations were performed with the innovative AngioSURF rolling table with integrated phased array surface coil and coronary TIRM sequences for different body regions. RESULTS: The results for WB-MRI and skeletal scintigraphy were concordant in 81% of the cases, whereby both procedures excluded skeletal metastases in 43%. WB-MRI and skeletal scintigraphy demonstrated skeletal metastases in 38% of the cases, whereby WB-MRI provided more comprehensive findings in 45%. In 12% of the cases, skeletal scintigraphy was superior to WB-MRI and in 19% the findings were discordant, whereby WB-MRI detected skeletal metastases in 15 cases which had not been found on skeletal scintigraphy. In nine cases, skeletal scintigraphy was positive when the WB-MRI was negative. In 60% of the cases, WB-MRI evidenced tumor-associated findings. CONCLUSION: WB-MRI represents a promising new staging technique for detection of skeletal metastases, which is more sensitive in many cases than skeletal scintigraphy in detecting and assessing the extent of skeletal metastases-and tumor-associated findings that are relevant for treatment strategy.

Adolescent↗

Endovascular treatment of superficial femoral artery occlusive disease with stents coated with diamond-like carbon.

A major consideration in the reduction of early stent thrombosis and in-stent restenosis is the improvement of biocompatibility of the devices. Diamond-like carbon is a novel material for coating stent surfaces in order to increase biocompatibility. The authors report on the endovascular treatment of two individuals with superficial femoral artery occlusions, using stents coated with diamond-like carbon. Technical and clinical success was achieved in both cases, with primary patency rates of 100% 12 months after intervention.

Aftercare↗

Totally implantable femoral vein catheters in cancer patients.

INTRODUCTION: Totally implantable devices are increasingly being utilized for chemotherapy treatment of oncological patients. When it is impossible to implant the reservoir on the anterior wall of the thorax, or when there is an obstruction of the superior vena cava system, alternative access routes must be sought. Of these, the femoral vein is the most utilized. Few studies have been performed to analyse the results obtained from the implantation and utilization of such catheters in the femoral vein. The goal of this work was to prospectively study the results obtained from the implantation of 20 TIC in femoral veins in a large-sized cancer hospital with its own dedicated vascular clinical team. MATERIAL AND METHODS: Twenty femoral TIC were inserted in 20 patients out of a group of 560 cancer patients submitted to TIC implantation for chemotherapy. Evaluations were made of the early and late-stage complications and patient evolution until removal of the device, death or the end of the treatment. RESULTS: The prospective analysis showed a mean duration of 215 days for the catheters. There were 16 patients with no complications. There were no early complications. Among the late complications, three were infections, representing 0.69/1000 days of catheter use, and one was a deep vein thrombosis (0.23/1000 days of catheter use). One catheter was removed due to primary bacteremia and one due to subcutaneous pocket infection. Fourteen patients died while the catheter was functioning and four patients are still making use of the catheter. CONCLUSION: The low rate of complications implying catheter loss in this study confirms the safety and convenience of the use of femoral TIC in patients who cannot be submitted to implantation in the superior vena cava system.

Adult↗

Investigations on the predictability of the formation of glassy solid solutions of drugs in sugar alcohols.

A prerequisite for the formation of glassy solid solutions prepared by the melting method is the miscibility of the respective drug and the carrier in the molten state. As could be shown experimentally, all investigated drug/sugar alcohol combinations miscible in the molten state form to some extent glassy solid solutions, dependent on their tendency to recrystallize during preparation. Therefore, the present study focuses on the evaluation of factors that govern the miscibility of molten drugs and sugar alcohols as carriers. In this context, solubility parameters are discussed as a means of predicting miscibility in comparison to a new approach, using calculated interaction parameters derived from molecular dynamics (MD) studies. There is evidence that a Coulomb interaction term C(SR), comprising short-range electrostatic interactions and hydrogen bonding energy is essential for the miscibility of drug and carrier in the molten state. To relate C(SR) to the molecular volume, a non-dimensional parameter P(i) is defined. For this parameter, a limiting value for miscibility exists. Contrary, calculated solubility parameter differences between drug and sugar alcohol in the range of 8-15 MPa(1/2) are not suitable for a prediction of miscibility or immiscibility, since the mixtures deviate from regular solution behavior. In irregular mixtures of drugs and sugar alcohols, an excess entropy and the formation of hydrogen bonds between unlike molecules favor miscibility, that cannot be predicted by regular solution theory.

Glass↗

[Ecthyma contagiosum (Orf) as an uncommon differential diagnosis of infections of the hand].

Orf of the hand is considered as an uncommon viral infection which is usually acquired through contact with infected sheep and goats. Indirect infections through contaminated knives or meat have been reported. Many authors feel that the disorder is more common than reported because the disease is often misdiagnosed and the course is usually self-limiting with spontaneous healing within several weeks. Diagnosis is mainly made by patient's history and clinical course. It is important to know the benign nature of human orf, since complications seem to be caused by overtreatment.

Biopsy↗

[Subperiosteal pisiform excision in misaligned fractures of the triquetrum].

Isolated fractures of the os triquetrum are a very rare condition, since they are usually combined with other fractures of the carpus. An undetected isolated fracture of the os triquetrum in a 28-year-old pieceworker revealed an osseous consolidation with a misalignment of the joint surface on presentation 6 months after his primary injury. During the whole time he was unable to work due to the severely painful restricted range of movement of his wrist. There are no general guidelines for treatment. Instead of correction of the anatomy of the os triquetrum, we decided to perform a subperiosteal pisiform excision according to Palmieri. As early as 6 weeks later, the patient was able to go back to work and demonstrated a pain-free full range of movement of his wrist. We encourage this procedure not only for degenerated joint disease but also for posttraumatic lesions in the early onset of painful blocking of the joint between the os triquetrum and os pisiforme.

Adult↗

[Electronic distribution of patient records and images through PACS: implementation of data protection at the University Hospital in Freiburg].

In large installations of a Picture Archiving and Communication System (PACS), data protection becomes an issue. Above all, not every employee should have access to all data stored in the system. At the Freiburg University Hospital, we developed a concept of dynamic assignment of authorization, assuring that every physician is authorized to the data of all patients under his care. We describe the technical implementation of data protection developed for the integration of PACS and electronic patient records in Freiburg. The system was installed in January 2001 and the experience of its two years in operation is reported.

Computer Security↗

CT-guided radiofrequency ablation of a bronchogenic carcinoma.

We report on the successful use of percutaneous CT-guided radiofrequency ablation (RFA) of a peripheral bronchogenic carcinoma in a 73-year-old patient. RFA was the favoured treatment option in this patient, who owing to comorbid factors was not a candidate for surgery. A 15 G LeVeen Needle Electrode (RadioTherapeutics, Sunnyvale, USA) with an array diameter of 3.0 cm was connected to a 200 Watt Generator (RF 3000, RadioTherapeutics, Sunnyvale, USA) and inserted into a 3.5 cm squamous cell carcinoma of the axillary subsegment of the right upper lobe. RFA resulted in complete tumour necrosis confirmed by histopathological examination. No complications such as a pneumothorax or bleeding occurred. Further clinical experience and prospective studies are necessary to determine the long-term efficacy of RFA in the treatment of lung tumours.

Aged↗

Using receiver operating characteristic methodology to evaluate the diagnostic quality of radiography on paper prints versus film.

OBJECTIVE: The aim of this study was to compare the diagnostic quality of paper prints with film copies in a sample of observers who were trying to detect small coin lesions on radiographs of a phantom. MATERIALS AND METHODS: The phantom consisted of 60 high-contrast and 60 low-contrast test objects, half of which had holes in them. Diameter and depth of the holes varied from 0.5 mm to 2 mm. Fifteen radiographs were obtained from different areas of the test objects. Film copies and paper prints were made using high-quality printers. Five observers independently evaluated 1,800 high-contrast and 1,800 low-contrast images. Data were evaluated using the well-established receiver operating characteristic methodology. RESULTS: The mean area under the curve rated 0.863 for paper prints (0.859 for high contrast and 0.860 for low contrast) and 0.926 for laser films (0.937 for high contrast and 0.913 for low contrast). The difference between the two imaging techniques was statistically significant for both high- and low-contrast lesions (p < 0.05). CONCLUSION: Detection of small coin lesions on radiographs of a phantom was significantly less sensitive on paper prints than on film. We found paper prints less acceptable for the diagnosis of small-sized lesions.

Diagnostic Errors↗

MRI-diffusion imaging of neuroblastomas: first results and correlation to histology.

The purpose of this study was to evaluate diffusion-weighted MR imaging in neuroblastomas. We prospectively examined seven children (age range 1-3 years) with seven solid body neuroblastomas. Diagnosis was established histologically. Diffusion-weighted echo-planar imaging (EPI) sequence was performed in all patients, with a repetition time of 5400 ms and an echo time of 103 ms, and with a b-value of 1000 s/mm(2). The contrast of tumour tissue depicted with T2-weighted images and diffusion-weighted images were evaluated by means of region-of-interest measurements and a calculation of the apparent diffusion coefficient (ADC) was done. The ADC calculation showed a mean ADC of 1.1x10(-3) (SD 0.14x10(-3), range 0.9-1.2x10(-3)) mm(2)/s of all tumours. Diffusion-weighted images showed an increased tumour signal. Water proton diffusion within the tumour matrix of neuroblastomas is especially restricted by the molecular and macromolecular barriers due to the very dense structure of this tumour tissue. We hypothesize that high nuclear-to-cytoplasm ratio of neuroblastoma cells limits intracellular motion. Furthermore, the very densely packed tumour cells inhibit effective motion of extracellular water protons. Restricted proton motion leads to a reduction in the rate of apparent diffusion and to a marked increase in signal on diffusion-weighted EPI MR images.

Adrenal Gland Neoplasms↗

Digital radiography with large-area flat-panel detectors.

Large-area flat-panel detectors with active readout mechanisms have been on the market for the past 2 years. This article describes different detector technologies. An important distinction is made between detectors with direct and those with indirect conversion of X-rays into electrical charges. Detectors with indirect conversion are built with unstructured or structured scintillators, the latter resulting in less lateral diffusion of emitted light. Some important qualities of flat-panel detectors are discussed. The first phantom and clinical studies published report an image quality at least comparable to that of screen-film systems and a potential for dose reduction. The available studies are summarised in this article.

Humans↗