[Principles of interventional treatment in epistaxis]. / Grundlagen der interventionellen Behandlung bei Epistaxis.

Epistaxis is a common ear, nose, and throat emergency, but rarely a direct cause for hospital admission. Patients who receive inpatient treatment usually suffer from recurrent posterior epistaxis. Despite otolaryngologic measures such as posterior packing or surgery, bleeding may recur or continue or the source may not be surgically accessible. For these patients, endovascular therapy is a real, sometimes the only, treatment option. In addition to idiopathic causes of posterior epistaxis, the cause may also be symptomatic. In this case, the cause must be identified and treatment adapted accordingly. Pre-embolization CT of the paranasal sinuses and CT-angiography is useful. These methods can reveal the cause and location of the hemorrhage as well as significant vessel variants, anatomic anomalies, or an unsuspected cause of epistaxis. Overall, with a good understanding of the dangerous anastomoses, endovascular therapy for posterior epistaxis has high success rates with a low periprocedural risk.

[Comparison of four digital and one conventional radiographic image systems for the chest in a patient study with subsequent system optimization]. / Vergleich von vier digitalen und einem konventionellen Röntgenaufnahmesystem für den Thorax mittels einer Patientenstudie mit nachfolgender Systemoptimierung.

PURPOSE: Using a patient study to prove the clinical relevance of a comparison of five different radiographic systems for the chest conducted with an anthropomorphic chest phantom. Depending on the results, it was tested whether the performance of a modern digital system with a transparent imaging plate can be improved by changing the post-processing of the image. METHOD: Chest radiographs of patients were taken with a CsI/aSi-flat panel detector (FDR), transparent imaging plate (tDLR), selenium drum detector (DSR), conventional storage phosphor plate (DLR) and asymmetrical screen-film-system (aFFS), and compared using image criteria scoring (ICS) and visual grading analysis (VGA) for anatomical structures (modified criterions of the EUR 16 260 EN guidelines). After optimizing the post processing, the images of the tDLR-system were evaluated once more in a phantom ROC study and patient VGA study. RESULTS: The flat panel detector-system proved to meet best the anatomical image quality criteria, followed by DSR, tDLR, aFFS and DLR. The modified post processing of the tDLR-images resulted in a significantly better detection of simulated pathological lung-structures, but improved the perceptibility of anatomical structures only slightly. CONCLUSIONS: The results of the patient VGA study and the phantom ROC study are similar and considered valid. The new digital imaging systems with flat panel detector and transparent imaging plate provide the best image quality of the tested radiographic devices for chest imaging, assuming that all system components are attuned and optimized for the type of structure to be detected. Image processing is of primary importance for system optimization.

[Chest radiography: ROC phantom study of four different digital systems and one conventional radiographic system]. / Thoraxübersichtsaufnahme: ROC-Phantomstudie an vier verschiedenen digitalen und einemkonventionellen Röntgenaufnahmesystem.

PURPOSE: To compare the diagnostic quality of five different radiographic systems used in chest radiography for visualization of differently configured, clinically relevant pathologic pulmonary structures. MATERIALS AND METHODS: Four digital detector systems using as detection unit a CsI/aSi-based flat panel detector, a transparent imaging plate, a selenium detector and a conventional storage phosphor plate were analyzed for this study, as well as an asymmetrical film-screen system. The analyzed imaging material consisted of radiographs of an anthropomorphic chest-phantom with superimposed simulated pulmonary structures. The images were evaluated for different pathologic structures by a newly developed multiple structure ROC (ms-ROC). RESULTS: The performance of each system was found to have a strong structure-related variability. The flat panel detector system had the best overall performance. The theoretical advantage of the 4k-matrix of the transparent imaging plate over the 3k-matrix of the flat panel detector was only confirmed for reticular structures. CONCLUSIONS: In addition to comparing the image quality of the different systems, this study shows that the performance of a radiographic system depends on the structure to be analyzed. The modified ROC (ms-ROC) provides valid results with less effort.

[Optimized image processing with modified preprocessing of image data sets of a transparent imaging plate by way of the lateral view of the cervical spine]. / Optimierte Bildverarbeitung durch ein modifiziertes Pre-Processing von Bilddatensätzen eines transparenten Speicherfoliensystems am Beispiel der seitlichen HWS-Aufnahme.

PURPOSE: To improve the diagnostic quality of lateral radiographs of the cervical spine by pre-processing the image data sets produced by a transparent imaging plate with both-side reading and to evaluate any possible impact on minimizing the number of additional radiographs and supplementary investigations. MATERIAL AND METHODS: One hundred lateral digital radiographs of the cervical spine were processed with two different methods: processing of each data set using the system-imminent parameters and using the manual mode. The difference between the two types of processing is the level of the latitude value. Hard copies of the processed images were judged by five radiologists and three neurosurgeons. The evaluation applied the image criteria score (ICS) without conventional reference images. RESULTS: In 99 % of the lateral radiographs of the cervical spine, all vertebral bodies could be completed delineated using the manual mode, but only 76 % oft the images processed by the system-imminent parameters showed all vertebral bodies. Thus, the manual mode enabled the evaluation of up to two additional more caudal vertebral bodies. The manual mode processing was significantly better concerning object size and processing artifacts. This optimized image processing and the resultant minimization of supplementary investigations was calculated to correspond to a theoretical dose reduction of about 50 %. CONCLUSION: The introduction of optimized organ programs for the upper and lower cervical spine based on the 12-bit data of the images should improve the evaluation of the lateral radiograph of the cervical spine without reducing the latitude value.

[First clinical experience with a full-size, flat-panel detector for imaging the peripheral skeleton - Part II: Post-processing with a newly developed adaptive autowindow algorithm]. / Erste klinische Erfahrungen mit einem grossformatigen Flächendetektorsystem bei Aufnahmen des peripheren Skelettsystems - Teil 2 : Nachverarbeitung mit einem neu entwickelten adaptiven Autofensteralgorithmus -

PURPOSE: of the second part of the investigation was the evaluation of a newly developed adaptive autowindow algorithm in comparison to the system processing radiographs of the wrist and ankle to further optimize the image quality with softcopy reading. MATERIAL AND METHODS: All 120 radiographs of the wrist and all 100 radiographs of the ankle used in the 1st part of this paper were processed with the adaptive autowindow algorithm. The evaluation was again performed by 5 radiologists with softcopy reading. For the data analysis a variation of the Visual Grading Analysis (VGA) was used. RESULTS: Up to 19 % of the wrist radiographs and 2 % of the ankle radiographs processed with the system software had to be processed manually afterwards to get acceptable results. By the application of the adaptive autowindow algorithm a manual post-processing was no longer necessary. Highly significant (p less-than-or-equal 0.001) differences for all criteria to be evaluated were found for the wrist radiographs and in the case of the ankle radiographs for the bone contrast, the contrast in soft-tissue regions, the fine details in the bone and the artifacts, the adaptive autowindow algorithm performed always better than the system software. CONCLUSION: Using half of the exposition dose on a flat-panel detector, an optimized post-processing leads to comparable or better results compared to the conventional film-screen-system concerning the image quality.

[First clinical experience with a full-size, flat-panel detector for imaging the peripheral skeletal system]. / Erste klinische Erfahrungen mit einem grossformatigen Flächendetektorsystem bei Aufnahmen des peripheren Skelettsystems - Teil 1: halbierte Patientendosis -

PURPOSE: This investigation was intended to show that exposures of the peripheral skeleton system can be done with half of the dose used for conventional screen-film systems with a full-size CsI/a-Si flat panel detector. MATERIAL AN METHODS: 120 exposures of the wrist and 100 exposures of the ankle have been made on a full-size flat panel detector system (43 x 43 cm). The patient dose has been reduced by a factor of two compared to conventional images. Five radiologists evaluated every image as a softcopy and a hardcopy image. For the evaluation, a variation of the Visual Grading Analysis (VGA) without reference images was used. For the determination of the patient entrance dose, measurement of a phantom were performed. RESULTS: A dose reduction of about 50 % is possible with the same or even better image quality in routine diagnostics. Only 3 % of the ankle and approx. 21 % of the wrist exposures required a postprocessing. Exposures with implants did not show any artifacts and some of the those achieved better evaluation results compared with exposures without implants. CONCLUSION: A halving of the patient dose is possible with acceptable results for the image quality. The effect of an improved image processing remains to be evaluated. The patient entrance dose is suitable for an evaluation of a radiographic detector and especially for a dose-referred comparison of digital X-ray units.

Classification of severe head injury based on magnetic resonance imaging.

OBJECT: In 1991 a new pioneering classification of severe head injuries had been proposed, based on CT findings. Unfortunately CT cannot visualise all lesions. Especially brain stem lesions may escape CT in spite of modern equipment, but may be demonstrated by MRI. The high incidence of CT negative but MRI positive posttraumatic brain stem lesions has already been demonstrated in a limited number of cases. A statistically significant evaluation is still missing. Therefore we have investigated a series of 102 comatose patients, in whom a statistical evaluation of MRI findings and their correlation with mortality and outcome of survivors was possible. PATIENTS AND METHODS: MRI was obtained within 8 days after servere head injury in 102 patients with a minimum of 24 hours of coma. The location of the lesions. identified by a neuroradiologist who was unaware of the clinical findings, was correlated with mortality, outcome of surviors and duration of coma. The correlation was analysed statistically. Follow-up ranged from 3 months to 3 years with a mean of 22 months. Four groups of lesions gave significant correlations: Grade I lesions were lesions of the hemispheres only; Grade II lesions were unilateral lesions of the brain stem at any level with or without supratentorial lesions; Grade III lesions were bilateral lesions of the mesencephalon with or without supratentorial lesions. Grade IV lesions were bilateral lesion of the pons with or without any of the foregoing lesions of lesser grades. RESULTS: Mortality increased from 14% in grade I lesions to 100% in grade IV lesions. The Glasgow outcome score differed significantly for each grade. The mean duration of coma increased from 3 days in grade I patients to 13 days in grade III. The correlations between the lesions grade I to IV with mortality, outcome of survivors and duration of coma were highly significant. CONCLUSION: The statistically significant correlations between the 4 groups of severe head injury patients, as identified by MRI, with mortality and outcome of survivors justify a new classification based on early MRI findings.

Digital selenium radiography: detection of subtle pulmonary lesions on images acquired with and without an additional antiscatter grid.

OBJECTIVE: the objective of this ROC-study was to evaluate the diagnostic efficacy of images acquired with a grid in digital selenium radiography compared to that on images obtained with the integrated air gap only. MATERIALS AND METHODS: seven types of simulated lesions were superimposed onto an anthropomorphic chest phantom. Selenium radiography images were obtained either with or without an additional antiscatter grid. For images acquired with a grid either a similar or increased exposure level was used. Both normal and obese patients were simulated. RESULTS: When a grid was used with an equivalent detector dose and a higher exposure, diagnostic performance was significantly improved as compared to images obtained with only the air gap. ROC curve areas for mediastinal nodules and catheters were substantially higher for images acquired with a grid and the same exposure level compared to images obtained without a grid. However, detection of linear, net-shaped and reticulonodular structures in peripheral lung regions was significantly worse when a grid was used with an equivalent exposure level. Concerning the interpretation of images obtained from the normal and obese phantom models, no substantial differences were observed. CONCLUSION: a marked improvement in diagnostic performance could be achieved by means of the use of an additional antiscatter grid and an equivalent detector dose. However, when the same exposure was used, images acquired with the grid allowed a better detection of mediastinal structures although a worse performance was evident in radiolucent lung regions. Therefore, the routine use of a grid without increased exposure is not recommended.

[Unusual computerized tomography and magnetic resonance imaging of cerebellar metastasis]. / Ungewöhnliche computertomographische und kernspintomographische Darstellung einer Kleinhirnmetastase.

In a 68-year old patient with brainstem/cerebellum abnormalities, a left cerebellar mass was demonstrated. It was characterized by hyperdensities in computed tomography; MRI revealed conspicuously low signal intensities on T2 weighting and isointense signal values with a peripheral gadolinium enhancement on T1 weighting. The histological finding was a metastasis of a mucus-forming adenocarcinoma which had originated in a tumor of the ascending colon.