Biomedical subjects

B Turowski

Publications and source records attributed to B Turowski.

31 records · Page 2Linked to original sources

PubMed1997

Imaging of intracranial aneurysm by three-dimensional contrast enhanced duplex sonography-two case reports.

We report two cases of intracranial aneurysms to give an impression of the use of three-dimensional (3-D) transcranial duplex sonography in combination with the application of a transpulmonary stable contrast agent. Data acquisition was performed with a free-hand scanning of the transducer (2 MHz) and a prototype of a new magnetic sensor system to track the spatial orientation of the ultrasound probe while scanning the volume of interest. The 3-D data were stored and afterwards 3-D reconstructions performed. Three-dimensional transcranial color duplex system with power Doppler mode showed an exact spatial orientation of the intracranial arteries. The three-dimensional system lets the reader retrospectively choose the section plane through the 3-D data set, and the reconstructions through the data set allowed us to localize aneurysms in both cases. The increased freedom of movement of the transducer allows the sonographer to maintain transducer contact with the skin, while offering the freedom to move the transducer as needed to remain on the acoustic window. Copyright 1997 Elsevier Science Ireland Ltd.

Journal Article↗

PubMed1997

[A new method for imaging intracranial cerebral arteries--3-dimensional transcranial duplex ultrasonography with image enhancement].

AIM: A new data acquisition system for transcranial 3 D-ultrasonography was used. The present study examines the evaluation of intracranial cerebral arteries by 3 D-ultrasound and echo contrast agents in comparison to cerebral angiography. METHODS: Ten patients, who underwent diagnostic cerebral angiography, were examined without knowledge of the angiographic results. Data acquisition through the transtemporal acoustic bone window was performed with a magnetic sensor system to track the spatial orientation of the ultrasound probe while scanning the volume of interest. We used a transcranial duplex system with power mode and stored a 3 D-data set before injection of transpulmonary stable contrast medium and afterwards. RESULTS: Ipsilateral to the transducer anterior cerebral artery (ACA) in 90%, middle cerebral artery (MCA) in 90%, three or more branches of MCA in 60% and posterior cerebral artery (PCA) in 40% were analysed without injecting an echo contrast agent. After the contrast injection ACA, MCA, branches of MCA and PCA in 100% were visible. In 70% of cases the posterior and anterior communicating arteries were visualised only by means of a contrast agent. CONCLUSION: Application of a transpulmonary stable ultrasound contrast agent in combination with 3 D transcranial duplex ultrasonography significantly enhances the visualisation of intracranial arteries.

Adult↗

PubMed1997

Diagnostic value of three-dimensional transcranial contrast duplex sonography.

This study evaluated intracranial cerebral arteries using a new data acquisition system for transcranial three-dimensional (3D) ultrasonography with and without an echo contrast agent, with confirmation by cerebral angiography. Ten patients, studied with diagnostic cerebral angiography, were examined without knowledge of the angiographic results. Data acquisition through the transtemporal acoustic window was performed using a magnetic sensor system to track the spatial orientation of the ultrasound probe while scanning the volume of interest. A color transcranial duplex system with a power Doppler mode was used, and 3D data sets were acquired before and after the injection of transpulmonary-stable ultrasound contrast medium. Ipsilateral to the transducer, the anterior cerebral artery (ACA) in 90%, middle cerebral artery (MCA) in 60%, all three or more branches of the MCA in 60%, posterior cerebral artery (PCA) in 60%, and posterior communicating artery (PCoA) in 60% were successfully imaged without the echo contrast agent. With the contrast agent, the ACA, MCA, three or more branches of the MCA, PCA, and PCoA were visible in 100%. The anterior communicating artery was visualized in 40% without contrast enhancement and in 90% with contrast enhancement. Contralateral to the transducer, the ACA (60%), MCA (30%), all three or more branches of the MCA (10%), PCA (20%), and PCoA (20%) were successfully imaged without contrast. Contrast enhancement improved the imaging success rate for the ACA (90%), MCA (80%), three or more branches of the MCA (80%), PCA (100%), and PCoA (100%). A transpulmonary-stable ultrasound contrast agent used in combination with 3D transcranial duplex ultrasonography can significantly improve the success rate for transcranial color duplex imaging of intracranial arteries.

Adult↗

PubMed1997

[Value of lung filter, asymmetric film-screen technique and digital storage screen radiography in diagnosis of coin lesion].

AIM: To evaluate the image quality of an asymmetric film-screen combination (a-FSC), a conventional screen-film combination (FSC) at speed class 200, a lung filter, and digital luminescence radiograms in detecting pulmonary nodules. METHODS: Detail perception studies were carried out with an anthropomorphic phantom. The image systems were exposed under standardised conditions with 125 kVp. The systems' perception efficiency was evaluated on the basis of 12.240 single observations with ROC analysis. RESULTS: In the overall evaluation the a-FSC and the filter achieved equally high assessments of 0.878 +/- 0.018 and 0.860 +/- 0.21 respectively (p > 0.05). The 200 speed FSC and the storage phosphor screen radiograms did not differ significantly. In the mediastinum all the tested systems were clearly superior to the 200 speed FSC (p < 0.05). In the lung fields on the other hand the 200 speed system was given a higher assessment of 0.866 +/- 0.026. The a-FSC had slight advantages over the lung filter and the digital imagining modes (p > 0.05). CONCLUSIONS: The a-FSC and digital luminescence radiograms provide significantly more diagnostic information in the mediastinum, together with high detail detectability in the lung fields and without requiring additional dosage.

Humans↗

PubMed1996

Frequency-filtered image post-processing of digital luminescence radiographs in pulmonary nodule imaging.

AIM: The aim of the study was to optimize unsharp masking image post-processing of digital luminescence radiographs (DLR) for the representation of pulmonary nodules, and to compare DLR to screen-film radiography at two dose levels. PATIENTS AND METHODS: A total of 284 CT-validated pulmonary nodules were evaluated. One hundred and forty-nine nodules were exposed with a 200-speed screen-film combination (SFC) and 135 nodules with a 400-speed SFC, with correspondingly exposed storage phosphor images. The kernal size in digital post-processing using 'unsharp masking' was varied between S 10 (2.83 mm) and S 70 (19.80 mm). A total of 11928 individual assessments were obtained from six independent observers and evaluated in multifactorial variance analyses. RESULTS: The large filter kernels of S 40 and S 70 were on a par with the 200-speed SFC (P > 0.05). As the exposure dose was reduced, the quality of the digital image vis-à-vis the 400-speed SFC improved significantly (P < 0.05). Smaller filter kernels (S 10; S 20) producing edge-enhancement processing were significantly inferior to the analog image technique in both dose ranges (P < 0.05). CONCLUSIONS: At speed class 200, low-frequency emphasizing digital image post-processing with large filter kernels are significantly superior to high-frequency emphasizing filtrations for the recognition of pulmonary nodules. In the lower dose range DLR with large filter kernel unsharp masking processing showed significantly improved image quality compared to 400 speed SFC for the detection of pulmonary nodules.

Adolescent↗

PubMed1996

ROC-analysis of detection performance by analogue and digital plain film systems in chest radiography.

PURPOSE: To compare the performances of 4 imaging systems in the diagnostic radiology of the chest: an asymmetric screen-film combination (a-SFC); a conventional screen-film combination of speed class 200 (SFC); a screen-film combination of speed class 200 with an aluminium lung filter; and digital luminescence radiographs (DLR). MATERIAL AND METHODS: Object detectability studies were carried out using an anthropomorphic chest phantom. The images were obtained under standard exposure conditions at 125 kVp. The detection performance of the various systems was evaluated by receiver operating characteristic (ROC) analysis on the basis of a total of 12,240 observations. RESULTS: In the overall evaluation the a-SFC and the SFC plus lung filter received equally high ratings of 0.878+/-0.018 and 0.860+/-0.21, respectively (p>0.05). There was no significant difference between the 200-speed SFC and the storage phosphor radiographs. In the mediastinum all the tested systems were clearly superior to the 200-speed SFC (p<0.05) while in the lung fields the 200-speed SFC received a high rating of 0.866+/-0.026. The a-SFC had slight advantages over the SFC plus lung filter and the 2 digital imaging modes (p>0.05). CONCLUSION: The a-SFC and the digital luminescence radiographs provide a significant gain in diagnostic information in the mediastinum without diminishing detail detectability in the lung fields and without additional radiation exposure.

Filtration↗

PubMed1996

[Progression of arthrosis after alloplasty--what factors play a role?].

From 87 patients who underwent anterior cruciate ligament (ACL) surgery with an alloplastic ligament (Trevira hochfest) the radiographs of 77 patients were examined by 2 physicians, who were not involved in the operation. They evaluated the increase of degenerative osteoarthritis according to the classification by Holz [12] finding a significant increase of degenerative osteoarthritis after surgery with a mean follow-up of 41.2 months. The ligament reconstruction was performed in 50 fresh ACL tears by reinsertion plus synthetic ligament protection and in 27 chronic instabilities with several failed previous operations by using the alloplastic ligament as an ACL prosthesis by means of a salvage procedure. Both investigators found a significant increase of degenerative osteoarthritis in both groups, but the chronically instable knees had a higher initial value. Patients with concomitant meniscus and/or posterior cruciate ligament (PCL) ruptures showed the highest increase of osteoarthritic changes; isolated ACL tears were found with very low degeneration. Considering the special profile of our collective, the factors that were found to as a risk of osteoarthritis and the comparison with the literature we could not find any indication for a relevantly increased risk of osteoarthritic progression using the Trevira hochfest ligament.

Anterior Cruciate Ligament↗

PubMed1995

[The use of an asymmetric film-screen combination for the imaging of round pulmonary foci].

PURPOSE: To examine the diagnostic advantages of an asymmetric film-screen system (a-FSS) compared to a conventional 200-speed FSS with and without anatomical lung filter. METHODS: Standard radiographs were obtained from an anthropomorphic chest phantom with simulated pulmonary nodules. The existence or non-existence of nodules was assessed in 7344 individual observations. The results were evaluated using ROC analysis. RESULTS: In an overall evaluation the a-FSS with an ROC area of 0.873 +/- 0.018 was not significantly superior (p > 0.05) to the lung filter but significantly superior (p < 0.05) to the 200-speed FSS. In the mediastinum the a-FSS and the lung filter were significantly superior (p < 0.05) to the 200-speed FSS. In the lung areas the 200-speed FSS and the a-FSS attained equivalent results (p > 0.05), whereas the lung filter was rated significantly lower (p < 0.05). CONCLUSIONS: Asymmetric FSS improves chest diagnostics, because it yields significantly more diagnostic information in the mediastinum using equivalent x-ray exposure without reducing the image quality in the lung areas in respect of simulated pulmonary nodules.

Evaluation Studies as Topic↗

PubMed1995

[Swelling of the sternoclavicular joint].

From 1990 through 1993 nine patients presented with unexplained swelling of the sternoclavicular joint. In some cases a tumor was suspected. The clinical histories included trauma with injury of forearm and wrist or strain on the shoulder girdle without acute onset of any symptoms in the sternoclavicular joint. In trauma cases the time from injury to onset of symptoms was between 1 day and 1 year (median 5 weeks). CT studies demonstrated widening of the joint space in two cases, thickening of the pectoral muscle in six cases and thickening of capsule and ligaments in five cases. In one case arthroplasty of the sternoclavicular joint was performed and in a second we performed a biopsy. The remaining cases were not treated. Other differential diagnoses to be considered in the case of a swelling of the sternoclavicular joint are listed.

Adolescent↗

PubMed1994

Which factors influence the progression of degenerative osteoarthritis after ACL surgery?

The knee radiographs of 77 patients were examined by two physicians not involved in the operation a mean of 41.2 months after implantation of a synthetic ligament (Trevira hochfest). They evaluated the increase of degenerative osteoarthritis on a five-grade scale (0-4) by Jonasch and Mohing as modified by Holz, and using the IKDC score. Fifty patients with acute rupture had the synthetic ligament implanted for protection of anterior cruciate repair. Twenty-seven patients had a salvage procedure with the alloplastic ligament functioning as a prosthesis. Both examiners found a statistically significant increase of degenerative arthritis. Patients with acute anterior cruciate tears had a lower degree of osteoarthritis on the day of surgery compared to the patients with chronic insufficiency, but the postoperative increase was identical in both groups. Statistical analysis revealed correlations between osteoarthric changes and several factors such as concomitant meniscus or posterior cruciate injury and demonstrated no correlation to the grade of postoperative stability or injuries to the medial or lateral collateral ligaments or capsule.

Adult↗

PubMed1993

[An atypical cause of a pulmonary embolism in a benign renal tumor].

The present case report describes a 20-year-old patient with a benign renal tumor (angiomyolipoma of the kidney). In the course of the nephrectomy a massive pulmonary embolism occurred with cardiac arrest. After reanimation, pulmonary angiography revealed a disseminated pulmonary embolism.

Adult↗

PubMed1984

Effect of a sulfonium analog of dopamine on the depolarization-induced release of [3H]acetylcholine from mouse striatal slices.

P3 have synthesized a chemical analog or dopamine in which the amino group has been replaced by a charged dimethylsulfonium group. The dopaminergic activity of this drug was evaluated by determining its ability to inhibit the depolarization-evoked release of [3H]acetylcholine from mouse striatal slices. The slices were preincubated with [3H]choline (0.1 microM) and then superfused in physiological medium. [3H]Acetylcholine release was induced by exposure of the slices to a high potassium medium (12.5 mM) for 5 min. The sulfonium analog of dopamine, dopamine, and apomorphine inhibited the evoked [3H]acetylcholine release with IC50 values of approximately 10, 2.0, and 0.3 microM respectively. The inhibition by the sulfonium analog was reversed by fluphenazine (1 microM), suggesting that the inhibition of [3H]acetylcholine release was due to the activation of dopaminergic receptors. The sulfonium analog also inhibited the uptake of [3H]dopamine into striatal slices and caused the release of exogenously taken up [3H]dopamine from these slices. The release of [3H]dopamine by the sulfonium analog was inhibited by cocaine (3 microM), suggesting that the drug-induced release of [3H]dopamine was dependent on the carrier-mediated uptake of the sulfonium analog into dopaminergic neurons. The inhibition of the evoked [3H]acetylcholine release by high concentrations (30 and 60 microM) of the sulfonium analog did not appear to be mediated by endogenous dopamine release, since the analog still inhibited [3H]acetylcholine release from slices after reserpine-alpha-methyl-p-tyrosine treatment. However, the inhibitory effect of the sulfonium analog at 10 microM was reduced by reserpine-alpha-methyl-p-tyrosine treatment, suggesting that the inhibition at lower concentrations was mediated through endogenous DA release. These results suggest that a charged compound can act as a substrate for the dopamine carrier and can activate the dopamine receptor regulating acetylcholine release. They also indicate that the nitrogen on the dopamine molecule is not essential for dopamine agonist activity.

Acetylcholine↗

PubMedDate not supplied

Mini-infarct encephalopathy associated with uncommon microvessel convolute formation presenting with presenile dementia.

A female patient started to suffer from transient ischemic attacks when she was 47 years of age, followed by increasing predominantly left-side spastic tetraparesis, generalized seizures and progressive dementia over a period of 11 years. She died when she was 58 years of age. On gross examination the brain showed enlarged ventricles and arteriosclerotic changes of large extracerebral vessels of the circulus arteriosus. Microscopic examination of the atrophic brain showed innumerable incomplete microinfarcts in the white and gray matter throughout all parts of the brain. In the white matter these lesions were characterized by small foci of demyelination and loss of oligodendrocytes while occasionally some scavenger cells were seen. Axons seemed to be unaffected or displayed irregular axonal regeneratory growth. Any inflammatory reaction failed. In the cerebral cortex and subcortical nuclei the lesions showed loss of neurons and decrease in synaptophysin expression. Intracerebral arteries showed fibrosis or fibrohyalinosis of the entire intracerebral small-vessel network. In addition, numerous uncommon clusters of angioma-like telangiectatic vessels were observed. Medium-sized ischemic infarcts were found in the right putamen and adjacent internal capsule region, left-side dorsolateral brain stem and cerebellar hemisphere as well as a left-side pyramidal tract degeneration. Contralateral pseudohypertrophy of the inferior olivary nucleus was seen. The clinical and the neuropathologic observations made in this patient are compatible with small vessel disease characterized by a multicentric special and not yet described type of incomplete mini-infarcts in cerebral cortex and white matter accompanied by some larger ischemic infarcts of the common type in brain stem and cerebellum.

Alzheimer Disease↗