Biomedical subjects

G Schulte-Altedorneburg

Publications and source records attributed to G Schulte-Altedorneburg.

At least 19 recordsLinked to original sources

PubMed2006

[Diagnosis and therapy of basilar artery occlusion].

In view of the poor prognosis for untreated patients with basilar artery occlusion, rapid delivery of effective treatment has the highest priority. Early recanalization by intra-arterial thrombolysis can improve the outcome in some patients. Apart from this method, specialized centers are increasingly using mechanical devices and glycoprotein IIb/IIIa inhibitors to achieve recanalization. This review focuses on current developments in the diagnosis and treatment of acute basilar artery occlusion.

Cerebral Angiography↗

PubMed2006

[Imaging techniques in diagnosis of brainstem infarction].

Twenty per cent of cerebral ischaemic infarctions involve tissue, supplied by the vertebrobasilar circulation. This overview of the current literature and our own experiences present the value of different imaging techniques (CT and MRI) and new developments for diagnosing brainstem infarction. Furthermore, the roles of invasive and noninvasive vascular imaging methods (computed tomographic angiography, magnetic resonance angiography, intra-arterial angiography, ultrasound) for evaluating vertebrobasilar stenosis and occlusion are described. The diagnostic workup of the most severe form of brainstem infarction, basilar artery thrombosis, is shown.

Brain Stem Infarctions↗

PubMed2006

[Postoperative syndrome after spine surgery].

Postoperative syndrome after spine surgery, i.e., symptoms or syndromes caused by complications or procedure-related consequences, is gaining more and more importance. Due to great improvements concerning imaging and operative techniques (microsurgery, instrumentation) the total number of spinal surgeries as well as their related complications are increasing. Procedure-related postoperative complications including neurological deficit syndromes can occur acutely or at a later date. Concerning imaging techniques for postoperative evaluation after spinal surgery there are several modalities available. Their indications depend on complex factors including initial pathology the surgery was performed for, kind of surgical technique (surgical approach, instrumentation), anatomy of the patient as well as the time between onset of symptoms and surgery. In cases of ambiguous findings, the combination of different imaging techniques can be instrumental.

Back Pain↗

PubMed2006

[Stroke].

Today stroke represents a major medical and political problem in Western industrial nations. High demands need to be placed on the initial diagnostic work-up and therapeutic treatment to ensure that the patients benefit from the recent advancements achieved in diagnostic and therapeutic fields. According to the motto "time is brain" the clinical examination and imaging have to be performed within 60 min ("door to needle time") so that potential patients can be quickly treated with systemic or intra-arterial lysis. However, it should be taken into consideration that the selection of diagnostic imaging facilities depends on several factors such as infrastructure, the time remaining in the diagnostic window, and the severity of the clinical symptoms.

Critical Care↗

PubMed2006

[Imaging of extradural spinal lesions].

There is a wide variety of spinal extradural tumors. In addition to real neoplasms, degenerative diseases, congenital abnormalities and inflammatory disorders can be causes of extradural masses. Due to the bony boundary of the spinal canal, both benign as well as malignant masses can cause progressive neurological deficits including paraplegia. Most of the spinal tumors are benign (hemangioma of the vertebral body, degenerative diseases). In younger patients congenital abnormalities and primary tumors of the spine have to be considered, whereas in adults the list of differential diagnoses should include secondary malignancies such as metastases and lymphomas as well as metabolic disorders such as osteoporotic vertebral compression fracture and Paget's disease. Cross-sectional imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT) of the spine often help to make a specific diagnosis of extradural spinal lesions and represent important tools for tumor staging and preoperative evaluation.

Diagnosis, Differential↗

PubMed2006

[Differential diagnosis of non-neoplastic space-occupying lesions of the spinal cord].

This overview addresses the topic of non-neoplastic intraspinal space-occupying lesions. Knowledge of these entities is essential to distinguish them from tumorous processes. A selection of clinically relevant differential diagnoses is presented which pertain to inflammatory, vascular, and degenerative diseases. In addition, special clinical findings, the radiological procedure, and therapeutic possibilities are outlined.

Angiography↗

PubMed2005

Evaluation of a new Spin-echo diffusion-weighted sequence on a 0.35 T open magnetic resonance imaging (MRI)-system: first experiences within 3 h after acute stroke.

In acute stroke, diffusion-weighted magnetic resonance imaging helps to select patients who are eligible for thrombolysis, but is almost exclusively implemented on closed-bore scanners, which make monitoring of patients difficult. We developed and tested a cardiac gated Spin-echo diffusion-weighted sequence with prescan finetrim and motion correction on an open system with 0.35 T. Nineteen stroke patients appropriate for thrombolytic therapy by clinical criteria were enrolled in a prospective study on an intention-to-treat basis. In all but one patient, computed tomography and magnetic resonance imaging including the new diffusion-weighted sequence were performed within 3 h after symptom onset. Images were evaluated for acute cerebral ischemia and hemorrhage by two radiologists blinded to clinical information. Magnetic resonance imaging required a mean total acquisition time of 26 min. Sensitivity for early infarction was 94% in diffusion-weighted imaging and 73% in computed tomography. Six patients were excluded from thrombolysis due to an infarct size of more than 1/3 of the territory of the middle cerebral artery exclusively diagnosed with diffusion-weighted imaging. Hemorrhage was recognised by both, magnetic resonance imaging and computed tomography. We conclude that in acute stroke, diffusion-weighted imaging with an open system at 0.35 T is practicable. The implemented sequence reliably demonstrated the size of the infarction and improved the selection of patients who are eligible for thrombolysis.

Adult↗

PubMed2005

Severe tick borne encephalitis with simultaneous brain stem, bithalamic, and spinal cord involvement documented by MRI.

A case of tick borne encephalitis (TBE) is reported, with simultaneous brain stem, spinal cord, and bilateral thalamic involvement confirmed by magnetic resonance imaging (MRI). After exposure to a TBE endemic region, the patient developed a biphasic clinical course with initial flu-like symptoms followed by a severe brain stem syndrome. The diagnosis of TBE was confirmed serologically. Repeated MRI scans showed brain stem, bithalamic, and spinal cord involvement. The outcome was favourable. TBE cases with concomitant myelitis tend to have a more severe clinical course and more likelihood of needing intensive care support. They should therefore be identified early in order to be prepared for life threatening respiratory complications.

Adult↗

PubMed2002

MR arthrography: pharmacology, efficacy and safety in clinical trials.

OBJECTIVE: A meta-analysis was carried out of clinical trials published between 1987 and 2001 in respect of the clinical pharmacology and safety as well as the diagnostic efficacy of gadolinium-DTPA (Gd-DTPA) for direct intra-articular injection before MRI examination. DESIGN: Scientific papers (clinical, postmortem and experimental studies) and information from the manufacturer regarding intra-articular injection of Gd-DTPA that addressed questions of mode of action, optimal concentration and dose, elimination and safety were reviewed. Clinical studies were classified according to their study design. The sensitivity, specificity and accuracy of MR arthrography (MRA) were compared with a "gold standard" (arthroscopy, arthrotomy) and other radiological evidence for different joints. RESULTS: Fifty-two clinical studies of the overall 112 studies addressed aspects of diagnostic efficacy of MRA in patients or in healthy volunteers. The shoulder was the most assessed joint (29 of 52 studies). Good (>80%) or even excellent (90-100%) sensitivity, specificity and accuracy were found for MRA in most indications, especially for the shoulder and knee joints and induced extension of rotator cuff lesions, labrum abnormalities and postoperative meniscal tears. Two millimoles per liter has proven to be the best concentration for intra-articular administration of Gd-DTPA. After passive complete diffusion from the joint within 6-24 h, complete and rapid renal elimination takes place after intra-articular injection. Local safety proved to be excellent after intra-articular administration of Gd-DTPA. Regarding systemic tolerance almost no side effects have been reported, but the same safety considerations apply for intra-articular administration of Gd-DTPA as for intravenous injection. CONCLUSIONS: The diagnostic efficacy of intra-articular MRA in most clinical conditions affecting major joints is greater than that of plain MRI. In some diagnostic problems MRA achieves almost the same sensitivity and specificity as the surgical gold standard. Given a sterile application, the intra-articular administration of Gd-DTPA in a concentration of 2 mmol/l prior to MRI is a safe procedure.

Arthrography↗

PubMed2001

Morphology and patency of Gore-Tex wrapped internal mammary artery bypass-evaluation with helical CT.

OBJECTIVE: To determine the patency of coronary internal mammary artery bypass (IMAB) with CT-angiography (CTA) and to evaluate the morphology of a covering Gore-tex IMAB-sleeve (PIMAS) used to protect the bypass at possible reoperation. MATERIALS AND METHODS: Sixty-five patients with IMAB wrapped with PIMAS (67 grafts) were prospectively investigated by CTA for bypass patency and sleeve morphology 6 months postoperatively with a standardised radiological and clinical protocol. RESULTS: All patent bypass arteries (62/62) were identified by CTA as open. In the remaining five cases, CTA revealed a bypass occlusion, which could be proven by coronary angiography in two cases (two patients refused angiography, one bypass was open angiographically). Morphology of the PIMAS could be imaged exactly in all cases. Sleeve implantation did not lead to adverse effects in terms of bypass occlusion or compression. In four patients, additional clinically relevant information were achieved. CONCLUSION: PIMAS implantation proved to be a safe procedure with good short-term results. CTA is a valuable method to exclude occlusion of sleeved IMA bypasses. Depiction of the wrapped IMAB by CTA supplies important information for preparing strategy in case of reoperation.

Adult↗

PubMed2001

Accuracy of in vivo carotid B-mode ultrasound compared with pathological analysis: intima-media thickening, lumen diameter, and cross-sectional area.

BACKGROUND AND PURPOSE: This study aimed to determine the correlation of in vivo ultrasound measurements of intima-media thickening (IMT), lumen diameter, and cross-sectional area of the common carotid artery (CCA) with corresponding measurements obtained by gross pathology and histology. METHODS: Sixty-six moribund neurological patients (mean age 71 years) underwent B-mode ultrasound of the CCA a few days before death. During autopsy, carotid specimens were removed in toto. Carotid arteries were ligated and cannulated for injection of a hydrophilic embedding material under standardized conditions. The carotid bifurcation was frozen and cut manually in 3-mm cross slices. Digital image analysis was carried out to determine the diameter and the cross-sectional area of the frozen slices of the CCA. IMT was assessed by light microscope. Ultrasonic and planimetric data were compared. RESULTS: Mean measurements of lumen diameter and cross-sectional area were 7.13+/-1.27 mm and 0.496+/-0.167 cm(2), respectively, by ultrasound, and 7.81+/-1.45 mm and 0.516+/-0.194 cm(2), respectively, by planimetric analysis of the unfixed redistended carotid arteries (R(2)=0.389 and 0.497). The mean IMT was 1.005+/-0.267 mm by ultrasound and 0.67+/-0.141 mm histologically, resulting in a mean difference of -31%. CONCLUSIONS: Transcutaneous B-mode ultrasound provides a reliable approach for in vivo measurements of the cross-sectional area and, less exactly, of the lumen diameter of the CCA. Compared with histological results, in vivo ultrasound measurements of the IMT are systematically larger.

Adult↗

PubMed2000

Serial CT and MRI of ischaemic cerebral infarcts: frequency and clinical impact of haemorrhagic transformation.

The frequency, predisposing factors and clinical consequences of haemorrhagic infarcts and damaged blood-brain barrier as shown by contrast enhancement (CE) in ischaemic cerebral infarcts are controversial. We prospectively compared the sensitivity of CT and MRI to haemorrhagic transformation (HT) and CE. We also wished to investigate the clinical significance of HT and factors possibly associated with it. We studied 36 patients with acute ischaemic infarcts in the middle cerebral artery territory during the first 2 weeks after the ictus. After CT and rating of the neurological deficit on admission, serial examinations with clinical neuromonitoring, contrast-enhanced CT and MRI were done on the same day. The occurrence and severity of HT were correlated with CE, stroke mechanism, infarct size, development of neurological deficits and antithrombotic treatment. The frequency of HT detected by MRI was 80%. CE usually preceded HT or was seen simultaneously. MRI had a higher sensitivity than CT to HT and CE. Severity of HT was positively correlated with infarct size (P < 0.01). HT had no influence on patient's neurological status. Neither the type of antithrombotic treatment nor the stroke mechanism was associated with the severity of HT. No parenchymal haemorrhage occurred.

Adolescent↗

PubMed2000

Preoperative B-mode ultrasound plaque appearance compared with carotid endarterectomy specimen histology.

In carotid artery stenosis both the degree of the lesion and its plaque morphology are thought to be associated with the carrier's thromboembolic risk. In this study we evaluated the diagnostic preciseness of non-invasively B-mode ultrasound in predicting the histopathological plaque structure. We examined 44 patients with > 50% ICA stenosis by B-mode within 6 weeks prior to carotid endarterectomy. At the affected bifurcations, up to 10 different regions of interest (ROI) per artery were investigated. Plaque appearance was classified according to 6 subtypes considering different ultrasonic plaque features. Postoperatively, plaque specimens were examined histopathologically for their relative content of calcification, fibrous tissue and different soft tissue. B-mode ultrasound was compared with histopathological features in ROI. A total of 265 regions of interest were evaluated. In mainly echolucent types of plaques, atheromatous debris was most frequently seen, whereas fibrosis was rare. Homogeneous echolucent plaques showed a high proportion of cholesterol and/or recent haemorrhage. Thrombosis at the plaque surface was often seen in "completely echolucent" plaque type (each P<0.001). Carotid B-mode ultrasonography is able to predict the histopathological components and the texture of carotid plaques.

Adipose Tissue↗

PubMed2000

Visualization of the basilar artery by transcranial color-coded duplex sonography : comparison with postmortem results.

BACKGROUND AND PURPOSE: Transcranial color-coded sonography (TCCS) via the suboccipital approach allows direct and continuous visualization of the basilar artery (BA). In this study, we intended to evaluate the ability of native TCCS in visualizing the length of the BA by means of a comparison with postmortem measurements. METHODS: The BA was prospectively studied by TCCS shortly before death (median 3 days) in 46 moribund neurological patients (mean+/-SD age 71.1+/-13.1 years). The length of the BA was determined by measuring the distance between the vertebrobasilar junction and the deepest available flow signal in the top of the BA. During autopsy, photos of the vertebrobasilar system were taken to evaluate the true anatomic length and variations of the course of BA in situ, eg, straight, curved, or S-shaped. RESULTS: Comparison of the in vivo ultrasound measurements of BA length and postmortem data was possible in 44 of 46 cases. In the 2 remaining patients, the BA was occluded. The mean insonation depth of the vertebrobasilar junction was found at 66.9+/-7.1 mm. The mean BA length was 21.5+/-6. 8 mm by color-coded duplex and 32.9+/-6 mm anatomically (P<0.0001). The mean difference between color mode and anatomic findings was 11. 3+/-6.4 mm in the case of a straight BA (35 cases) and 16.3+/-4.8 mm in an anatomically tortuous course of the BA (9 cases). CONCLUSIONS: Color duplex imaging enables correct visualization of the proximal two thirds of the BA, but only exceptionally of its distal one third. A tortuous course of the BA leads to an underestimation of its anatomic length.

Basilar Artery↗

PubMed2000

Dynamic CT perfusion imaging of acute stroke.

BACKGROUND AND PURPOSE: Because cerebral perfusion imaging for acute stroke is unavailable in most hospitals, we investigated the feasibility of a method of perfusion scanning that can be performed rapidly during standard cranial CT. Our aim was to identify the scanning parameters best suited to indicate tissue at risk and to measure a perfusion limit to predict infarction. METHODS: Seventy patients who had suffered stroke and had undergone cranial CT 0.5 to 12 hours (median, 3.75 hr) after the onset of symptoms participated in the study. While undergoing conventional CT, each patient received a bolus of iodinated contrast medium. Maps of time to peak (TTP), cerebral blood volume (CBV), and CBF were calculated from the resulting dynamically enhanced scans. These perfusion images were compared with follow-up CT scans or MR images showing the final infarctions. RESULTS: CBF maps predicted the extent of cerebral infarction with a sensitivity of 93% and a specificity of 98%. In contrast, CBV maps were less sensitive and TTP maps were less specific and also showed areas of collateral flow. Infarction occurred in all of the patients with CBF reduction of more than 70% and in half of the patients with CBF reduction of 40% to 70%. CONCLUSION: Dynamic CT perfusion imaging safely detects tissue at risk in cases of acute stroke and is a feasible method for any clinic with a third-generation CT scanner.

Acute Disease↗

PubMed1999

Four-gated transcranial Doppler ultrasound in the detection of circulating microemboli.

OBJECTIVE: Embolus detection by transcranial Doppler ultrasound is very time consuming and semi-automated detection is mandatory. The device studied, a TC4040, Nicolet-EME, uses the four-gate technique and allows for audiovisual off-line verification of the recorded events. METHODS: Twenty controls, 10 patients with mechanical prosthetic heart valves and 12 patients with occlusive carotid artery disease were investigated by transcranial colour-coded duplex sonography and, subsequently, underwent a 1-h unilateral embolus detection from the middle cerebral artery using four-gate TCD. We investigated the Doppler spectrum background, microembolic signals (MES) and artefacts produced. A detection threshold of 5 dB or more was defined taking into account natural fluctuations of the Doppler spectrum. RESULTS: Sensitivity of the software was 91.9% and observer-software agreement on MES was 7.8% in the valve patients, and 77.7% and 7.5% in the carotid artery disease patients, respectively. Weaker MES were more likely not to be detected in all four channels. The artefact signal rejection rate was 62%. MES produced either positive or zero time delays in adjacent channels. Artefact signals produced either no delay, or a positive or a negative time delay. Duration of MES ranged from 1-88 ms. CONCLUSIONS: Besides refined recognition of MES using the time delay, four gates give faint MES no less than four opportunities to overcome the detection threshold. With this device's satisfying sensitivity, regions of interest in a 1-h recording can audiovisually be evaluated off-line in a few minutes by an investigator.

Adult↗

PubMed1999

Absence of circulating microemboli in patients with lone atrial fibrillation.

Atrial fibrillation (AF) is a well-recognized independent risk factor of ischemic stroke. The aim of this study was to investigate the amount of microembolic signals (MES) in 15 patients with 'lone' AF representing the subgroup of AF patients with the lowest lifelong risk of stroke. All patients had been put on effective anticoagulation due to a scheduled electric cardioversion. Additional cardiac and arterial sources of embolism were excluded by echocardiography and extracranial color-coded duplex sonography of the carotid arteries. Unilateral one-hour transcranial Doppler monitorings revealed complete absence of MES in this series. This observation fits the concept that the amount of microembolisation is related to the risk of manifest thromboembolism. Further studies on this patient group treated with less intensive antihemostatic therapy should be undertaken to define more clearly the disease-specific microembolic activity.

Aged↗

PubMed1999

Diagnostic benefit of echocontrast enhancement for the insufficient transtemporal bone window.

Echocontrast agents (ECA) are known to improve transcranial color-coded duplex (TCCD) imaging, but its diagnostic benefit in the routine clinical setting has not clearly been defined. The authors investigated the diagnostic benefit of ECA application in 54 patients with insufficient transtemporal bone window, consecutively referred to their ultrasound laboratory. According to the precontrast imaging quality, patients were assigned to three categories: A, no intracranial structures or vessel segments visible on B-mode imaging and TCCD (n = 5); and intracranial structures visible on B-mode imaging and vessel segments less than 5 mm in length (B, n = 21), or larger than 5 mm in length (C, n = 28) visible on TCCD. The effect of the echocontrast enhancement was assessed with respect to signal enhancement, imaging quality, and diagnostic confidence. In 49 out of 54 patients (91%), a significant improvement of the imaging quality was noted, enabling 43 (80%) neurovascular diagnoses of sufficient diagnostic confidence. The diagnostic ECA effect was strongly dependent on the precontrast imaging quality: upon echoenhancement, a satisfactory image quality was obtained in none of the patients of category A, as opposed to 16 (76%) and 27 (96%) patients of categories B and C, respectively. In summary, in 80% of our consecutive patient series with insufficient transtemporal bone window, application of ECA allowed for a conclusive TCCD study. Properties of the transtemporal precontrast scans are strongly predictive of the diagnostic benefit and should be taken into the decisive consideration.

Adult↗