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Biomedical subjects

W Steinbrich

Publications and source records attributed to W Steinbrich.

At least 55 records · Page 3Linked to original sources
PubMed1996

Proton chemical shift imaging, metabolic maps, and single voxel spectroscopy of glial brain tumors.

Seventeen patients with presumed glial brain tumors were examined with proton chemical shift imaging and single voxel spectroscopy that used different echo times. Metabolite resonances were evaluated by metabolic ratios and absolutely by correcting for coil load and comparison to phantom measurements. Metabolic images were created to visualize the metabolic changes. All patients showed spectra that were different from those measured in healthy control subjects. Spectral changes were also present in normal-appearing matter (NAM) that was distant from lesions. The resonance at 3.55 ppm which is usually assigned to both myo-inositol and glycine, was the only one to allow a discrimination between healthy volunteers, astrocytoma grade II, and glioblastoma multiforme (GBM) (p < 0.02). From the different echo times used we conclude that an increase in this resonance has to be assigned to glycine rather than myo-inositol. This resonance might be used to grade human gliomas more reliably. Total creatine (Cr) decreased more drastically with malignancy than N-acetylated metabolites (NA). This led to a higher NA/Cr ratio in GBM compared to astrocytoma grade II. NA/Cr was thus pseudonormal in GBM due to a change in both nominator and denominator. This study reveals the importance of comparing magnetic resonance spectroscopy data of lesions to spectra measured in identical localizations in healthy control subjects instead of NAM and the importance of quantifying single metabolic peaks instead of creating metabolic ratios in clinical magnetic resonance spectroscopy.

Adult↗
PubMed1996

Evaluation of the clinical safety and efficacy of iobitridol (Xenetix) in intravenous urography.

The aim of this study is to report on the clinical safety and diagnostic efficacy of iobitridol (Xenetix) in intravenous urography compared to iohexol (Omnipaque) or iopamidol (Iopamiro). A total of 120 patients underwent intravenous urography (i.v.u.); 60 received Xenetix and 60 either Omnipaque (30 patients) or Iopamiro (30 patients) according to the center where they were treated. Clinical safety was assessed by the reporting of adverse events and diagnostic efficacy was evaluated. Warmth sensation was the most commonly reported adverse event. Two cases of nausea and vomiting were reported. Concerning diagnostic efficacy, 72-74% of the i.v.u. examinations were rated good or excellent by the physician. These studies confirm that Xenetix is a suitable contrast agent for i.v.u.

Contrast Media↗
PubMed1996

Lower extremity angiography: improved image quality and outflow vessel detection with bilaterally antegrade selective digital subtraction angiography. A blinded prospective intraindividual comparison with aortic flush digital subtraction angiography.

RATIONALE AND OBJECTIVES: To introduce routine bilaterally antegrade selective stationary digital subtraction angiography (DSA), and prospectively compare it with unselective stationary DSA in the detection of calf arteries and assess additional time and complication rate. METHODS: Twenty-five patients received one unselective and two separate antegrade selective studies of each calf. Images were evaluated for image quality, number of depicted run-off vessels, and potential crural bypass recipient arteries. RESULTS: Bilaterally antegrade selective DSA was significantly superior in image quality and motion artifacts (P < 0.01). The number of adequately depicted run-off arteries per calf increased from 79% (2.37 of 3) to 96% (2.89 of 3) for legs with advanced peripheral vascular disease (PVD). Seventy-nine instead of 62 potential bypass recipients were identified (P = 0.002). Mean procedure time needed for selective catheterizations was 7 minutes. No adverse events were seen. CONCLUSIONS: Bilaterally antegrade selective DSA clearly is superior to aortic run-off DSA depicting tibial arteries. It requires comparatively small additional effort. Outflow vessel detection essentially is independent of advanced PVD.

Aged↗
PubMed1996

Value of repeat-angiography in cases of unexplained subarachnoid hemorrhage (SAH).

PURPOSE: To investigate the rate of false negative initial cerebral angiography in spontaneous SAH and to ascertain why aneurysms remain undetected. Furthermore to validate CCT in predicting the presence and site of an angiographically missed aneurysm. METHODS: Forty-two patients with spontaneous SAH were investigated, in whom initial cerebral angiography did not reveal any bleeding cause. Repeat-angiography was performed in all patients 5 to 55 days (mean 15 days) after the bleeding event. All patients underwent CCT scans within 48h after the ictus. RESULTS: In 8 of 42 patients (19%) repeat-angiography revealed an aneurysm missed on initial angiography. The aneurysms were located on the AcomA (n = 2), the MCA (n = 2), the ACA (n = 1), the PICA (n = 2) and the junction of ICA and PcomA (n = 1). Presumable reasons for missing an aneurysm were spasms detected in four of eight cases on initial angiography and thrombosis of the aneurysm found in two cases at surgery. In two cases, multiple additional views just revealed the aneurysm appearing different in size and shape on repeat-angiography. CCT blood distribution pattern in four cases indicated presence and site of an aneurysm, while blood distribution was non-specific in the other four cases. CONCLUSION: Repeat-angiography plays an important role in defining the site of an initially occult aneurysm and should be performed in all cases of unexplained SAH. It is of particular importance if vasospasm has compromised the initial angiogram or if one part of the vascular tree is not optimally seen.

Adult↗
PubMed1996

Solitary pulmonary nodules: MR evaluation of enhancement patterns with contrast-enhanced dynamic snapshot gradient-echo imaging.

PURPOSE: To evaluate the enhancement patterns of solitary pulmonary nodules (SPNs) with dynamic contrast-material-enhanced magnetic resonance (MR) imaging to differentiate between benign and malignant SPNs. MATERIALS AND METHODS: Twenty-eight patients with SPNs 30 mm or smaller in diameter were examined with pre- and postcontrast, electrocardiographically gated, T1-weighted spin-echo (SE) sequences and a snapshot gradient-echo (GRE) sequence after bolus injection of a paramagnetic contrast agent. For all SPNs (20 malignant, eight benign), the percentage increase in signal intensity (%SI) on the postcontrast T1-weighted SE images and the enhancement curves (%SI/sec) for the snapshot GRE measurements were established from regions of interest. RESULTS: Malignant nodules showed a higher increase of signal intensity during the first transit of the bolus of contrast material on the dynamic snapshot GRE images (malignant: median, 18.1 %SI/sec; range, 6.7-95.2 %SI/sec; benign: median, 2.3 %SI/sec; range, 0.1-8.1 %SI/sec) (P < .0001). Static T1-weighted SE measurements did not allow differentiation between malignant (median, 53.4 %SI; range 12.5-110.0 %SI) and benign (median, 33 %SI; range, 0.8-85.5 %SI) (P > .2) nodules on the basis of the degree of contrast enhancement. CONCLUSION: Dynamic contrast-enhanced MR measurements of tumor enhancement can provide additional information about the nature of SPNs.

Adult↗
PubMed1996

Anatomic evaluation of the circle of Willis: MR angiography versus intraarterial digital subtraction angiography.

PURPOSE: To evaluate the reliability of source images and maximum intensity projection images of MR angiography in showing the arterial segments of the circle of Willis. METHODS: In 62 patients, 526 arterial segments of the circle of Willis were determined to be present, partially present, or absent by blinded observers evaluating MR angiographic source images and maximum intensity projection images. Vessel diameter was measured on source images. These results were then compared with the results from intraarterial digital subtraction angiography. RESULTS: MR angiographic maximum intensity projection images had a sensitivity of 87% and a specificity of 88% and MR angiographic source images had a sensitivity of 89% and a specificity of 63% in depicting the presence of a vessel segment. The positive predictive value of an arterial segment with a diameter of at least 1 mm was 99%. CONCLUSION: MR angiography is a sensitive technique for detecting the anatomy of the circle of Willis. Maximum intensity projection images are more specific than source images. An arterial segment with a diameter of at least 1 mm on the source image is almost always present and patent.

Adolescent↗
PubMed1995

[Xanthogranulomatous pyelonephritis with phlegmonous abdominal wall infiltration. Diagnosis and assessment of extent via computerized tomography].

A 34-year-old woman who 14 years previously had undergone a left nephrotomy for nephrolithiasis complained of pain in the left renal fossa which was reddened and painful on percussion. She had a fever of 38.2 degrees C. C-reactive protein was raised to 80 mg/l, the white cell count to 14,620/microliters (83% neutrophils). Protein and white cells were found in the urine together with a significant number of E. coli on urine culture. Plain film of the abdomen showed a staghorn calculus and ultrasonography demonstrated renal enlargement with a possible paranephritic abscess. The computed tomography diagnosis was xanthogranulomatous pyelonephritis, on the basis of renal enlargement, staghorn calculus, hypodense areas with typical density values (10-15 Hounsfield units), contrast enrichment and extrarenal extension of partly phlegmonous partly fused-together inflammatory changes. The abscessing parts were drained under computed tomography control. Starting 7 days pre-operatively the patient had been receiving ciprofloxacin (0.4 g daily) intravenously. A nephrectomy had to be performed subsequently. Antibiotic treatment was discontinued 2 weeks later and she was discharged symptom-free. The diagnosis of diffuse xanthogranulomatous Pyelonephritis was confirmed by histological examination of the surgical specimen.

Abdominal Abscess↗
PubMed1995

[Perimesencephalic subarachnoid hemorrhage: clinical and computer tomography aspects].

AIM: The blood distribution on CCT and the prognosis of patients with nonaneurysmal subarachnoidal haemorrhage were retrospectively studied and compared to a patient group with aneurysmal haemorrhage. METHODS: The blood distribution on CCT (72 h after bleeding episode) of 26 patients with nonaneurysmal subarachnoidal haemorrhage confirmed by two normal cerebral angiograms was compared to the blood distribution of 76 patients with aneurysmal haemorrhage. The clinical condition of these patients was further analysed, 4-60 months after the bleeding episode. RESULTS: In 62% of patients with nonaneurysmal haemorrhage the blood distribution was perimesencephalic. The aneurysmal blood distribution pattern was more extended and only one patient showed a perimesencephalic pattern. 80% of the patients without aneurysms in angiography had no limitations in daily functional capacity. CONCLUSION: The perimesencephalic pattern is frequently found in patients with nonaneurysmal subarachnoidal haemorrhage, the prognosis of these patients is excellent. Rarely is the perimesencephalic haemorrhage caused by a ruptured aneurysm. It needs thorough angiographic evaluation.

Adult↗
PubMed1995

[A comparative study of the imaging quality and picture dosage of a new conventional film-screen system for skeletal x-ray diagnosis].

PURPOSE: This paper compares a new film-screen system (FSS) called INSIGHT Skeletal Imaging System with the previously used Lanex/T-MAT G FSS. MATERIAL AND METHODS: Using a Bronder phantom, measurements were made of dose, resolution and contrast. 135 skeletal phantom images were assessed in order of quality by six observers. RESULTS: Comparable high resolution film-screen combinations (FSC) showed similar geometric resolution. Comparing high intensifying screens, the new INSIGHT Skeletal Regular FSS showed better resolution than the Lanex medium FSC. Dose reduction for the INSIGHT Skeletal Imaging FSS was 29-56%. The new FSS showed image quality similar to high resolution screens but was significantly better when using high intensifying screens. CONCLUSION: The new INSIGHT Skeletal Imaging System can replace the Lanex/T-MAT G FFS by retaining quality but reducing radiation dose by 29-56%. Using the new high intensifying FSC, images showed in addition improved film quality.

Bone and Bones↗
PubMed1995

Treatment of malignant obstruction of the superior vena cava with the self-expanding Wallstent.

BACKGROUND: Obstruction of the superior vena cava (SVC) in malignant disease can cause considerable distress to patients. Symptomatic relief can be achieved by the percutaneous implantation of a self-expanding stent (Wallstent) into the stenosis. METHODS: Fourteen patients with obstruction of the SVC were treated with one to three Wallstent endoprostheses. They suffered from advanced bronchogenic carcinoma (n = 12), thyroid carcinoma (n = 1), and breast carcinoma (n = 1). The indication for stent placement was symptomatic obstruction of the SVC and incurable disease. Stenting was performed for symptom relief, and before, during, and after courses of radiotherapy or chemotherapy as needed. RESULTS: Twelve patients experienced complete symptomatic relief within two days of stent placement. Two patients did not benefit. Three patients not given anticoagulation developed stent thrombosis between one week and eight months after initial placement, and within one day of endobronchial stent implantation with bronchial laser therapy or balloon dilatation in all three. Patency of the SVC was achieved again by a repeat procedure. CONCLUSIONS: Stent placement for obstruction of the SVC gives rapid symptomatic relief. Subsequent endobronchial stent implantation with bronchial laser therapy or balloon dilatation could be a risk for caval stent occlusion. Stent thrombosis remains a problem in patients who are not anticoagulated.

Aged↗
PubMed1995

Intracranial arteries: prospective blinded comparative study of MR angiography and DSA in 50 patients.

PURPOSE: To compare the reliability of magnetic resonance (MR) angiography performed with magnetization transfer suppression and variable flip angle excitation with that of intraarterial digital subtraction angiography (DSA) in imaging of the cerebral arteries. MATERIAL AND METHODS: Fifty nonconsecutive patients referred for intraarterial DSA gave informed consent to also undergo MR angiography of the intracranial arteries. RESULTS: MR angiography had a sensitivity of 100% and a specificity of 95% for detection of vessel occlusion (10 abnormalities). For detection of substantial vessel stenosis (seven abnormalities), sensitivity and specificity were both 86%; for detection of aneurysm (six abnormalities), sensitivity was 83% and specificity was 98%. Sensitivity and specificity were 100% for detection of arteriovenous malformation (three abnormalities), vessel displacement (three abnormalities), and extracranial-intracranial bypass (two abnormalities). MR angiography did not reliably demonstrate small feeding vessels of a tumor or faint residual perfusion of a thrombosed aneurysm. CONCLUSION: MR angiographic diagnosis of disease of the intracranial vasculature has high sensitivity and specificity but still is limited in comparison with intraarterial DSA.

Angiography, Digital Subtraction↗
PubMed1995

Arterial pseudoaneurysm as a complication of percutaneous transhepatic biliary drainage: treatment by embolization.

We observed a serious arterial hemorrhage as a complication of percutaneous transhepatic biliary drainage (PTBD). The hemorrhage appeared during catheter placement for implantation of an endobiliary stent as a two-step procedure. It was caused by an arterial pseudoaneurysm and could be successfully treated by superselective embolization. Although there was a preexisting cavernous transformation of the portal vein no signs of liver cell necrosis appeared after embolotherapy. Vascular complications of PTBD will be discussed with regard to their frequency, possible etiology, ways to avoid them and their interventional therapy.

Aged↗
PubMed1995

[Diagnostic possibilities of magnetic resonance tomography (MRT) and magnetic resonance angiography (MRA) in popliteal artery entrapment syndrome (PAES)].

MRT offers some advantages for morphological examinations of the fossa poplitea and appears to be superior in terms of multiplanar imaging over CT and duplex sonography for identifying a PAES. The method is always indicated when the diagnosis of PAES is suspected from the primary duplex sonography but the verification of the anatomic alteration is not conclusive. An MR angiography can, in principle, be carried out in the same session. On consideration of the currently presented cases, both inflow and phase-contrast MRA appear to be suited for examination. However, a sufficient detail resolution is only achieved by use of a surface coil which then makes assessment of the contralateral side and the lower leg arteries impossible. Specially fitted coils which allow a double-sided representation of sufficient image quality may, however, make conventional angiography unnecessary in future.

Adult↗
PubMed1994

[The findings and value of computed tomography in pleural empyema].

Chest radiographs and CT images of 25 patients with pleural empyemas were compared retrospectively with those of 20 patients with pleural exudates and transudates in order to determine criteria for differential diagnosis and to define the place of CT in the diagnosis of pleural empyemas. The sign which was most suggestive of an empyema on a chest radiograph was an encapsulated effusion in an atypical position (18/25); this was found in only 4 out of 20 exudates and in none of the transudates. On CT, changes in the pleura, the subcostal tissues and the configuration and position of the fluid were suggestive of an empyema. In nearly all patients with a pleural empyema there was thickening and increased contrast uptake of the parietal pleura (22/25) and thickening and increased density oft the subcostal tissues (23/25). Usually, empyemas were encapsulated and biconvex (20/25). None of the patients with pleural transudates showed any of these changes. In the presence of some pleural exudates, pleural (14/20) or thoracic (11/20) changes were noted. In part, these changes were due to previous treatment (sclerotherapy) or tumour infiltration (7/20). An attempt to correlate the CT findings with changes in the pleura and subcostal tissues with the clinical empyema stages I-III, according to Light, showed that CT was unable to distinguish between early and late empyemas. Consequently, diagnostic aspiration remains necessary for correct treatment.

Adult↗
PubMed1993

[Severe hemoptysis in pulmonary vasculitis].

A 27-year-old man, in good health but a moderate smoker, suddenly had two episodes of haemoptysis. Routine clinical examination was unremarkable. Erythrocyte sedimentation rate was increased to 34 mm/h. The chest radiography showed ill-defined, contrast-poor infiltrations bilaterally, as well as left hilar enlargement. Lung scintigraphy and pulmonary arteriogram suggested pulmonary embolism, possible from a "pelvic vein spur", i.e. an intimal proliferation due to crossing of the common iliac artery over the pelvic vein. He was placed on oral anticoagulants. Three months later he had another severe haemoptysis, providing the indication for an exploratory thoracotomy. This revealed the left pulmonary artery wall to have inflammatory changes with aneurysmal dilatation. The aneurysm was plicated. Histological examination demonstrated chronic vasculitis as seen in Behçet's syndrome, a diagnosis confirmed by the findings of ulcers of the oral mucosa and the presence of HLA B5 allo-antigens. Immunosuppressive treatment was given with prednisone (1 mg/kg), azathioprine (2.5 mg/kg) and ciclosporin (5 mg/kg). Over the next 12 months there has been only one further haemoptysis.

Adult↗
PubMed1993

[Intracranial lymphoma. Radiologic findings in 40 patients].

We analysed the radiologically findings of 40 patients with histologically confirmed cerebral lymphoma but without AIDS in a retrospective study; 31 of these had primary cerebral lymphoma without any other manifestation of the disease. All patients had CT, 24 had angiography and in five patients MRT had been performed in addition. CT showed a solitary lesion in 60%, of these 62% had scalloped margins and 38% were nodular, 34% were isodense and 57% were hyperdense. Following contrast injection, there was increased density in 97% of the lesions. The most frequent localisation was in the region of the basal ganglia and the corpus callosum (33%), in the frontal lobes (30%) and in the temporal lobes (20%). Angiographically, 63% showed evidence of a space-occupying lesion, there were vascular irregularities in 33% and tumour contrast in 21%; in 25% of the patients angiography was normal. Early venous filling was not found in any case. T1 weighted sequences during MRT of 5 patients showed the tumour to be isointense or slightly hypointense. T2 weighted images showed the tumour to be hyperintense or with mixed signal intensities.

Adolescent↗