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Biomedical subjects

P Springer

Publications and source records attributed to P Springer.

At least 19 recordsLinked to original sources
PubMed2000

Virtual computed tomography colonoscopy: artifacts, image quality and radiation dose load in a cadaver study.

The purpose of our study was to evaluate the interdependency of spatial resolution, image reconstruction artifacts, and radiation doses in virtual CT colonoscopy by comparing various CT scanning protocols. A pig's colon with several artificial polypoid lesions was imaged after air insufflation with helical CT scanning using 1-, 3-, and 5-mm collimation, and pitch values varying from 1.0 to 3.0. Virtual endoscopic images and "fly through" sequences were calculated on a Sun Sparc 20 workstation (Navigator Software, GE Medical Systems, Milwaukee, Wis.). Several reconstruction artifacts as well as overall image quality were evaluated by three independent reviewers. In addition, radiation doses for the different CT protocols were measured as multiple-scan average dose using a 10-cm ion chamber and a standard Plexiglass body phantom. Generally, image quality and reconstruction artifacts were less affected by pitch values than by beam collimation. Thus, narrow beam collimation at higher pitch values (e. g. 3 mm/2.0) seems to be a reasonable compromise between quality of virtual endoscopic images and radiation dose load.

Animals↗
PubMed2000

Adjunctive thalidomide therapy of childhood tuberculous meningitis: possible anti-inflammatory role.

The objective of this study was to determine the safety and tolerability of the immunomodulatory agent thalidomide as adjunct therapy in children with tuberculous meningitis. Children with stage 2 tuberculous meningitis received oral thalidomide for 28 days in a dose-escalating study, in addition to standard four-drug antituberculosis therapy, corticosteroids, and specific treatment of complications such as raised intracranial pressure. Clinical and laboratory evaluations were carried out. Fifteen patients (median age, 34 months) were enrolled. Thalidomide was administered via nasogastric tube in a dosage of 6 mg/kg/day, 12 mg/kg/day, or 24 mg/kg/day. The only adverse events possibly related to the study drug were transient skin rashes in two patients. Levels of tumor necrosis factor-alpha in the cerebrospinal fluid decreased markedly during thalidomide therapy. Clinical outcome and neurologic imaging showed greater improvement than that experienced with historical controls. Thalidomide appeared safe and well tolerated in children with stage 2 tuberculous meningitis and could have important anti-inflammatory effects. These promising results have led us to embark on a randomized, double-blind, placebo-controlled trial of the efficacy of thalidomide in tuberculous meningitis.

Adjuvants, Immunologic↗
PubMed1999

Diagnosis of digital flexor tendon annular pulley disruption: comparison of high frequency ultrasound and MRI.

PURPOSE: The objective of this study is to assess accuracy of ultrasound (US) and MRI to diagnose completely disrupted annular pulley ligaments (APL) of the flexor tendons of the fingers. PATIENTS AND METHODS: In a prospective study 32 patients (all males 18-42 years, mean age 25 years) with clinically suspected annular pulley disruption were studied with US and MRI. As a control group we investigated 40 fingers of 10 healthy volunteers and a non-injured finger of the patients with US. A 10 MHz linear array was used for US examinations and a 1.5 Tesla unit for MRI. Imaging was performed between the accident and surgical repair within 6 weeks. Examinations were performed in an extended and forced flexed finger position. RESULTS: Complete disruption of the APL was diagnosed by US and MRI in 14 cases confirmed by surgery. The typical sign of disruption was a marked volar displacement of the flexor tendon in the area of the torn annular pulley during forced flexion. A distance between tendon and bone at the area of the ruptured pulley of 3 mm during extension and a distance of 5 mm at flexion was typical for complete disruption. CONCLUSION: Both diagnostic modalities, US and MRI are valuable techniques in diagnosing complete disrupted annular pulleys of the flexor tendons.

Adult↗
PubMed1999

Aneurysmal portosystemic venous shunt: a case report.

A case of an aneurysmal portosystemic venous shunt detected by colour Doppler ultrasound (CDUS) is presented. A young female patient complained of postprandial fatigue and had paroxysmal tachycardia. A direct vascular communication between right portal vein and right hepatic vein was found at CDUS and confirmed by direct portal angiogram. Using detachable coils a complete occlusion of the intrahepatic shunt was obtained. Reports from the literature regarding portovenous aneurysms are reviewed.

Adult↗
PubMed1999

Incidental findings on sonography of the breast: clinical significance and diagnostic workup.

OBJECTIVE: The purpose of this study was to determine how often physician-performed high-resolution sonography can detect nonpalpable breast lesions not revealed by mammography. A sonographic classification scheme was tested for its accuracy in predicting malignancy of incidentally detected breast lesions. SUBJECTS AND METHODS: Six thousand one hundred thirteen asymptomatic women with breast density grades 2-4 and 687 patients with palpable or mammographically detected breast masses underwent sonography as an adjunct to mammography. All sonographically detected, clinically and mammographically occult breast lesions that were not simple cysts were prospectively classified into benign, indeterminate, or malignant categories. Diagnoses were confirmed by sonographically guided fine-needle aspiration or core needle biopsy. RESULTS: In 6113 asymptomatic women, 23 malignancies in 21 patients were detected with sonography only (prevalence, 0.31%). Five additional malignant lesions were found in patients with a malignant (n = 3) or a benign (n = 2) palpable or mammographically detected index lesion. The mean size of invasive malignancies detected only by sonography was 9.1 mm, which was not significantly different from the mean size of invasive cancers detected by mammography (p = .07). The sensitivity of the prospective sonographic classification for malignancy was 100%, and the specificity was 33.5%. CONCLUSION: The use of high-resolution sonography as an adjunct to mammography in women with dense breasts may lead to detection of a significant number of otherwise occult malignancies that are no different in size from nonpalpable mammographically detected lesions. Prospective classification of these lesions based on sonographic characteristics results in a significant reduction in number of unnecessary biopsies performed.

Aged↗
PubMed1998

Sonographic appearance of an appendix carcinoma.

Malignant appendix tumours are rare entities. Especially adenocarcinomas, which only appear in about 10% of appendix tumours, are very seldom. Preoperative diagnosis is very difficult due to a lack of typical clinical signs and a clinical appearance mimicking perforated appendicitis. Nevertheless, sonography is able to show indirect signs and therefore it can provide the surgeon with more information for a better operative treatment.

Adenocarcinoma↗
PubMed1998

[Doppler ultrasound determination of vascular resistance in arteriovenous shunts of the finger tip].

AIM: Doppler sonographic assessment of physiological bloodflow characteristic in arteriovenous shunts of the fingertip and calculation of vascular resistance. Identification and definition of a peripheral, physiological resistive index in healthy volunteers. METHOD: Doppler sonographic measurement of bloodflow values in Hoyer-Grosser organs of the fingertip in 20 healthy volunteers. Measurements were repeated at normal air temperature (21 degrees C) and after submersion in water (15 degrees C). The resistive index was calculated from peak systolic velocity and minimal diastolic velocity. RESULTS: Although bloodflow values vary in a wide range, the resistive index is constant with 0.54 (range 0.45-0.69) in healthy volunteers. Characteristic sonographic flow patterns could be achieved in all tests. CONCLUSIONS: Colour Doppler sonography allows identification of small arterio-venous shunts of the fingertip, measurement of bloodflow in these vessels and calculation of vascular resistance. At normal air temperature the physiological resistive index is 0.54.

Adult↗
PubMed1998

[Ruptures of the medial gastrocnemius muscle: diagnosis with high resolution ultrasound].

AIM: Evaluation of high resolution ultrasound to diagnose rupture of the medial head of gastrocnemius muscle in patients with uncharacteristic calf pain. METHOD: 66 patients with clinically unclear calf pain were examined in a prospective study. RESULTS: Out of 66 patients, 51 showed sonographic criteria of a partial rupture of the medial gastrocnemius head. 47 ruptures were located in musculotendineus transition zone. CONCLUSION: High resolution sonography detect minimal lesions of the medial gastrocnemius muscle in patients with clinically uncharacteristic calf pain.

Adult↗
PubMed1998

[ACOnet (Austrian Academic Computer Network) as data carrier for teleradiologic consultations].

PURPOSE: To assess the feasibility of image transfer for teleradiologic consultations using the Austrian Academic Computer Network (ACOnet). The ACOnet corresponds between the main universities to a MAN (Metropolitan Area Network) with a transfer rate of 4 Mbps. Its use is free of charge for university institutions. MATERIALS AND METHODS: 1740 test image data sets and 620 image data sets for teleradiological consultations were exchanged without annotations between the Departments of Diagnostic Radiology of the universities of Innsbruck and Graz, using the ACOnet. RESULTS: Data transmission was reliable and fast with an average transfer capacity of 170.2 kBytes/s (94-341 kBytes/s). There were no major problems with image transfer during the test phase. CONCLUSION: Due to its high transfer capacity, the ACOnet is considered a reasonable alternative to the ISDN service.

Austria↗
PubMed1998

Rating nursing performance based on behaviors.

If used effectively, performance appraisal systems keep employees focused on the vision and mission of the organization. Appraisal tools firmly grounded in desired behaviors can be effective in improving performance. The authors describe the steps and development of a Behavior Anchored Rating Scale (BARS) for registered nurses and give readers information for developing behaviorally based evaluation tools.

Behavior↗
PubMed1998

The Austrian Academic Computer Network and its usefulness for teleradiology.

To study the value of the Austrian Academic Computer Network (ACOnet) for teleradiology, 1740 test image data-sets and 620 image data-sets were exchanged between the departments of diagnostic radiology of the Universities of Innsbruck and Graz using the ACOnet service. Data transmission was reliable and fast with an average transfer capacity of 170 kByte/s (range 94-341). During the test phase, no major problems with image transfer occurred. Assuming that problems like security of patient data-sets, data compression and data verification can be solved, the ACOnet service would be a useful additional tool for telemedicine applications throughout Austria and eastern Europe.

Austria↗
PubMed1998

Intensive short course chemotherapy in the management of tuberculous meningitis.

SETTING: Short course chemotherapy for tuberculous meningitis (TBM) is advocated by several groups, but relatively few children have been so treated and followed up. METHODS: A prospective, observational study of isoniazid (INH), rifampicin (RMP) and ethionamide (ETH) in a dosage of 20 mg/kg, and pyrazinamide (PZA) 40 mg/kg, all given once daily in hospital for 6 months. Surviving children were followed up for a year after discharge. RESULTS: Ninety five children, 39 (41%) at stage III, 52 (55%) at stage II and 4 (4%) at stage I TBM were studied. Ten (26%) at stage III and 3 (6%) at stage II died before completion of therapy. Five surviving children (6%) moved on discharge and were untraceable; seven children (9%) were lost during follow up and three were inadvertently restarted on antituberculosis therapy. Two children with severe stage III disease died after discharge. One child experienced a probable disease recrudescence 1 month after discharge. Eighteen children (20%) developed a mildly elevated serum bilirubin concentration during the first month of treatment. In five of these children INH, RMP, ETH and PZA were stopped and streptomycin (SM) and ethambutol substituted. In all cases the original treatment was restarted without incident. One child developed overt jaundice after 5 months of treatment due to hepatitis A infection. CONCLUSIONS: Our experience suggests that young children with TBM can be safely treated for 6 months with high doses of antituberculosis agents without overt hepatotoxicity and with a low risk of relapse.

Antibiotics, Antitubercular↗
PubMed1997

Virtual computed tomography gastroscopy: a new technique.

BACKGROUND AND STUDY AIMS: The aim of the present study was to establish a suitable method for virtual computed tomography (CT) gastroscopy. PATIENTS AND METHODS: Three-millimeter helical CT scans of a pig stomach were obtained after air insufflation and instillation of diluted diatrizoic acid (Gastrografin), and with double contrast. In addition, three patients with gastric tumors were studied after ingestion of an effervescent agent (Duplotrast, 6 g) and intravenous injection of hyoscine butylbromide (Buscopan, 1 ml). Virtual endoscopy images were computed on a Sun Sparc 20 workstation (128 megabytes of random access memory, four gigabytes of hard disk space), using dedicated software (Navigator, General Electric Medical System Company). The endoscopy sequences were compared with real endoscopic examinations and with anatomical specimens. RESULTS: In the cadaver studies, the best results were obtained with plain air insufflation, whereas virtual CT gastroscopy with diluted contrast and with double contrast showed artifacts simulating polyps, erosions, and flat ulcers. Patient studies showed good correlation with the fiberoptic endoscopy findings, although large amounts of retained gastric fluid substantially reduced the quality of the surface reconstruction. CONCLUSION: These preliminary results show that virtual CT gastroscopy is able to provide insights into the upper gastrointestinal tract similar to those of fiberoptic endoscopy. However, due to the limited spatial resolution of the CT protocol used, as well as inherent image artifacts associated with the Navigator program's reconstruction algorithm, the form of virtual CT gastroscopy studied was not capable of competing with the imaging quality provided by fiberoptic gastroscopy.

Animals↗
PubMed1997

[Virtual endoscopy with post-processing helical CT data sets].

PURPOSE: The purpose of this work was to test a newly developed, post-processing software for virtual CT endoscopic methods. Virtual endoscopic images were generated from helical CT data sets in the region of the shoulder joint (n = 2), the tracheobronchial system (n = 3), the nasal sinuses (n = 2), the colon (n = 2), and the common carotid artery n = 1). Software developed specifically for virtual endoscopy ("Navigator") was used which, after a previous threshold value selection, makes the reconstruction of internal body surfaces possible by an automatic segmentation process. We have evaluated the usage of the software, the reconstruction time for individual images and sequences of images as well as the quality of the reconstruction. All pathological findings of the virtual endoscopy were confirmed by surgery. RESULTS: The post-processing program is easy to use and provides virtual endoscopic images within 50 seconds. Depending of the extent of the data set, virtual tracheobronchoscopy as a cine loop sequence required about 15 minutes. Through use of the threshold value-dependent surface reconstruction the demands on the computer configuration are limited; however, this also created quality problems in image calculation as a consequence of the accompanying loss of data. CONCLUSIONS: The Navigator software enables the calculation of virtual endoscopic models with only moderate demands on the hardware.

Artifacts↗
PubMed1997

[Open questions on the topic of teleradiology from the current viewpoint].

A review on the theoretical challenges and potential risks of teleradiology is given. Based on the authors two years clinical experience and the current literature unsolved problems are discussed, which are to a smaller extent the technical implementation but much more the still missing regulation of various concomitant circumstances.

Computer Security↗