Biomedical subjects

Isabel Wanke

Publications and source records attributed to Isabel Wanke.

At least 19 recordsLinked to original sources

PubMed2006

Whole-body MR vascular screening detects unsuspected concomitant vascular disease in coronary heart disease patients.

Coronary heart disease (CHD) patients often show atherosclerotic vascular disease in other vascular territories. We evaluated how often whole-body MR imaging detects concomitant arterial pathologies in CHD patients, and how often these pathologies were not known to the patients previously. Of 4,814 participants in the population-based Heinz Nixdorf Recall Study, 327 reported CHD (i.e., previous coronary bypass surgery, angioplasty); of those, 160 patients (mean age 66.4 years) were examined using MR of the brain, the heart (excluding the coronary arteries), and whole-body MR angiography. The prevalence of each vascular pathology was assessed, correlated to the others and compared to patients' histories. Of the 160 CHD patients, 16 (10%) showed MR signs of stroke, and 77 (48.1%) had a stenosis >50% in at least one extracerebral peripheral artery (other than the coronaries), including 28 (17.5%) with relevant renal artery stenoses, and 20 (12.5%) with relevant extracerebral internal carotid artery stenoses. False negative histories were reported in 12 of 81 cases with myocardial infarctions, and in 11 of 16 cases with cerebrovascular infarctions. This whole-body atherosclerosis MR screening program allows previously unknown concomitant vascular disease to be detected in coronary heart disease patients. Its prospective value should be assessed in further studies.

Aged↗

PubMed2006

Balloon-assisted coil embolization of a posterior cerebral artery aneurysm via a persistent primitive trigeminal artery: technical note.

INTRODUCTION: We present a patient with an acutely ruptured, wide-necked aneurysm of the left posterior cerebral artery (PCA) treated with Guglielmi detachable coils using the remodeling technique. METHODS: Since the left vertebral artery was compressed due to a tumor in the cerebellopontine angle and the right vertebral artery was hypoplastic, we used a carotid artery approach via a persistent primitive trigeminal artery (PPTA) to selectively catheterize the aneurysm. RESULTS: The aneurysm was occluded completely. CONCLUSION: To our knowledge this is the first case of a wide-necked PCA aneurysm treated via a PPTA and using the remodeling technique. In patients with hypoplastic vertebral arteries and a PPTA, this approach may represent an alternative for selective embolization of posterior circulation aneurysms not amenable to the conventional approach.

Adult↗

PubMed2006

Horizontal stent placement plus coiling in a broad-based basilar-tip aneurysm: an alternative to the Y-stent technique.

INTRODUCTION: Basilar tip aneurysms are the most frequent type of aneurysm in the posterior circulation. Specifically, if wide-necked, they remain a significant therapeutic challenge. On the endovascular side, stents may help to overcome many of these technical challenges. However, if both P1 segments encroach into the aneurysm neck, sometimes stent placement from the middle of the basilar artery to one P1 segment is not enough. Therefore, some groups recommend the use of the so-called Y-stent technique, with one stent passing through the interstices of another stent in a Y-configuration thus remodelling the basilar tip. METHODS: We describe a patient with a broad-based basilar tip aneurysm and a single, very tortuous vertebral artery which did not allow the use of the vertebrobasilar system as the straight route to the aneurysm. Because of the well-known high surgical risk we decided to navigate the stent through the internal carotid artery and via the posterior communicating artery into the contralateral P1 segment and placed the stent at right angles to the aneurysm from one P1 segment to the contralateral one. RESULTS: The outcome in the patients was excellent without any ischemic lesions. CONCLUSION: Horizontal stent placement in wide-necked basilar tip aneurysms may be a therapeutic alternative if the regular route via the vertebral arteries is not feasible.

Blood Vessel Prosthesis Implantation↗

PubMed2005

Gender-specific cerebral activation during cognitive tasks using functional MRI: comparison of women in mid-luteal phase and men.

Previous studies of gender-specific differences in functional imaging during spatial and language tasks have been inconclusive. Furthermore, among women, such differences may occur during mid-luteal phase compared to the rest of the menstrual cycle. In order to examine further gender differences, functional MRI was performed in 12 male volunteers and 12 female volunteers (in the mid-luteal phase) during mental rotation and verb-generation tests. Two-sample t-tests with uncorrected P values of <0.001 for the specific regions of interest (ROIs) revealed cerebral activation differences in both stimuli. During mental rotation tests, higher levels of activation were noted in the right medial frontal, precentral, and bilateral inferior parietal cortex, while in women this occurred in the right inferior and medial temporal, right superior frontal cortex, and left fusiform gyrus. During verb-generation tests, higher levels of activation in men was found in the left medial temporal and precentral cortex. Our results indicate that differences in cerebral activity during cognitive tasks can be shown between men and women in the mid-luteal phase. Gender differences while performing a mental rotation task were more prominent than during a verb-generation task.

Adolescent↗

PubMed2005

Comparison of volume, four- and eight-channel head coils using standard and parallel imaging.

Array coils can potentially offer increased signal-to-noise ratio (SNR) over standard coils adjacent to the array elements, while preserving the SNR at the center of the volume. The SNR advantage should theoretically increase with the number of array elements. Parallel acquisition techniques (PAT), on the other hand, can benefit acquisition times or spatial resolution at a cost to SNR as well as image quality. This study examines the question of whether SNR and image quality are still acceptable with two different array coils (four and eight channels) in conjunction with PAT when compared to standard imaging with a volume coil. All imaging was on a 1.5 T MR scanner. T2-weighted, FLAIR, diffusion-weighted, and time of flight (TOF) angiography images were performed with and without PAT in a phantom and in ten healthy volunteers. The phantom measurements demonstrated superior SNR for the eight-channel coil versus the four-channel and standard head coils. Using the eight-channel head coil for in vivo imaging, image quality with PAT (acceleration factor=2) was scored similar to images without PAT using the volume coil. The four-channel head coil suffered from inhomogeneity, lower SNR and poorer image quality when using PAT compared to standard imaging with the volume head coil. Both the in vivo and the phantom results indicate that the eight-channel head coil should be used for the highest quality brain images; this coil can be combined with PAT sequences for shorter acquisition time without a significant decrease in image quality relative to a volume coil without PAT.

Adult↗

PubMed2005

T1 Gd-enhanced compared with CISS sequences in retinoblastoma: superiority of T1 sequences in evaluation of tumour extension.

BACKGROUND: As adequate therapy for retinoblastoma in young children depends on infiltration of extra-retinal structures, diagnostic modalities play an essential role. METHODS: In this widely extended study, 80 children with retinoblastoma were studied with MRI (standard fat-suppressed Gd-enhanced T1, T2 thin-slice sequences (additionally with small loop surface coil), constructive interference in steady state (CISS) sequence covering the orbita). The images were analysed by two blinded neuroradiologists. Histology was used as the gold standard. RESULTS: MRI assumed infiltration of extra-retinal structures in 13 of 80 patients of which ten were confirmed by histology. Affected extra-retinal structures were: optic nerve (five, of which two were on CISS and three on T1 with higher image resolution using the surface coil), scleral infiltration (five, of which four on CISS and T1) and ciliary body infiltration (one on CISS and T1). Another 61 enucleated patients did not have any extra-retinal infiltration in histology. The CISS sequence with multiplanar reconstruction was mainly helpful in revealing exact three-dimensional tumour extension with excellent clinical acceptance and pre-surgical planning but T1 fat-suppressed Gd-enhanced images were superior in revealing exact tumour extension. CONCLUSION: CISS sequences allow to produce excellent anatomical images and to perform multiplanar reconstruction to better demonstrate tumour extension. However, T1-weighted sequences after contrast application are more sensitive (60 versus 40%) in detecting infiltration of the optic nerve but equal in detecting scleral infiltration.

Child↗

PubMed2005

Neuroimaging of infections.

Neuroimaging plays a crucial role in the diagnosis and therapeutic decision making in infectious diseases of the nervous system. The review summarizes imaging findings and recent advances in the diagnosis of pyogenic brain abscess, ventriculitis, viral disease including exotic and emergent viruses, and opportunistic disease. For each condition, the ensuing therapeutic steps are presented. In cases of uncomplicated meningitis, cranial computed tomography (CT) appears to be sufficient for clinical management to exclude acute brain edema, hydrocephalus, and pathology of the base of skull. Magnetic resonance imaging (MRI) is superior in depicting complications like sub-/epidural empyema and vasculitic complications notably on FLAIR (fluid-attenuated inversion recovery)-weighted images. The newer technique of diffusion-weighted imaging (DWI) shows early parenchymal complications of meningitis earlier and with more clarity and is of help in differentiation of pyogenic abscess (PA) from ring enhancing lesions of other etiology. Proton magnetic resonance spectroscopy (PMRS) seems to produce specific peak patterns in cases of abscess. The presence of lactate cytosolic amino acids and absence of choline seems to indicate PA. Also in cases of suspected opportunistic infection due to toxoplasma DWI may be of help in the differentiation from lymphoma, showing no restriction of water diffusion. In patients with herpes simplex and more exotic viruses like West Nile and Murray Valley virus DWI allows earlier lesion detection and therapeutic intervention with virustatic drugs.

Animals↗

PubMed2005

Water excitation: a possible pitfall in cerebral time-of-flight angiography.

BACKGROUND AND PURPOSE: Time-of-flight MR angiography (TOF MRA), with its advantage of high spatial resolution, is widely used for visualization of intracranial arteries. Fat signal intensity from bone marrow can interfere with vessel signal intensity, especially in maximum intensity projection reconstructions. Use of a technique such as fat saturation or water excitation can reduce this signal intensity. METHODS: Ten volunteers were included in this study. TOF MRA was performed by using spoiled gradient echo sequences on a 1.5-T MR unit either with or without water excitation. Water excitation was performed by using a binomial excitation pulse pair, with a null in the excitation profile at the fat frequency to obtain fat suppression. Two blinded neuroradiologists then judged the images. Additional studies by using a phantom with a flow of about 2 mL/s were performed under the same conditions. Image quality obtained with and that without water excitation was graded as similar by both neuroradiologists. RESULTS: As the main finding, the sequences by using water excitation revealed an important pitfall: apparent carotid artery stenosis was detected in 4/10 and occlusions in 1/10 cases. Use of a flow phantom could reveal the same pitfall. Intracranial vessel disease was excluded in all volunteers by using Doppler sonography. CONCLUSION: The type of water excitation tested here can induce significant artifacts in cerebral TOF MRA. These artifacts can be misinterpreted as carotid artery stenosis or even occlusion, whereas the benefit brought by water excitation with respect to fat suppression is less significant.

Adult↗

PubMed2005

A novel flexible, retrievable endovascular stent system for small-vessel anatomy: preliminary in vivo data.

BACKGROUND AND PURPOSE: This study assessed the in vivo delivery, retrievability, short-term patency, and cellular response to a new flexible endovascular stent system in a rabbit model. The stent is designed for delivery through a microcatheter and is fully retrievable with electrolytic detachment from a delivery wire. METHODS: We successfully deployed nine stents (range of sizes, 2.5-4 mm diameter, 15-35 mm length) in six straight (carotid) and three angled (subclavian) arteries of six Chinchilla Bastard rabbits. Serial imaging was performed by using intravenous digital subtraction angiography (IVDSA), contrast-enhanced MR angiography (CEMRA), time-of-flight MR angiography (TOF), and CT-angiography 3 days and 4 weeks after stent deployment. Subjects were euthenized after 4 weeks (n = 5), and stents were removed for histologic analysis. RESULTS: Stent deployment was feasible in all cases. After initial deployment, all stents could be fully retrieved within the microcatheter. The detachment zone and the distal stent marker were easily visible under fluoroscopy, and final detachment occurred reliably in all cases. We observed no procedural complications. Noninvasive imaging by using IVDSA, MR angiography, and CT angiography was feasible in this stent system and demonstrated all arteries patent and not narrowed at 3 days and 4 weeks, findings that were confirmed by histologic analysis. CONCLUSION: This electrolytically detachable stent is promising as a treatment for intracranial arteries, because it can be delivered through microcatheters small enough for intracranial navigation. It is fully retrievable, thus providing greater control than currently available stents. Noninvasive imaging by using IVDSA, MR angiography, and CT angiography is feasible in this stent system and may be useful for follow-up. Further long-term data are needed.

Animals↗

PubMed2004

Mutations in the lysyl oxidase gene not associated with intracranial aneurysm in central European families.

BACKGROUND: Lysyl oxidase is a promising candidate gene for a mutation search in intracranial aneurysm families because (a) it controls the processing, cross-linking and maturation of collagen and elastin fibers in the blood vessel wall, (b) its expression levels and activity are altered in different animal models of aneurysm pathogenesis, and (c) it is encoded within the chromosome 5q22-31 region of suggestive linkage to intracranial aneurysms. METHODS: We have performed genomic sequencing of all 7 exons including the intron-exon splice sites and of the putative promoter region for lysyl oxidase in 25 patients from intracranial aneurysm multiplex families resident in Central Europe. RESULTS: We observed 4 genetic variants including 2 novel polymorphisms, 1 in the noncoding sequence of exon 7 and the other upstream from the lysyl oxidase promoter. None of these single nucleotide polymorphisms showed an allelic association or cosegregation with intracranial aneurysm in the families. CONCLUSIONS: Genetic variants in the lysyl oxidase gene do not appear to be a major factor in the etiology of intracranial aneurysms in Central Europe.

Adenine↗

PubMed2004

Clipping versus coiling: neuropsychological follow up after aneurysmal subarachnoid haemorrhage (SAH).

Patients treated with microsurgical clipping of ruptured intracranial aneurysms often suffer from neuropsychological deficits in spite of a good neurological outcome. The purpose of this study was to explore if the deficits are related to the type of therapy. Two groups of 16 patients each suffering from aneurysmal SAH, matched for sex, age, aneurysm-site and Hunt and Hess score, and 16 control subjects were examined with a battery of neuropsychological tests including memory, attention, and executive function. Depression, mood, and quality of life were also assessed. One patient group had been treated with surgical clipping, the other with endovascular coiling. Both patient groups showed deficits in verbal and visual memory. Clipped patients were slightly more impaired than coiled patients, especially on measures of affect and on a self-assessment measure of executive function. The pattern of results suggests that the neuropsychological outcome after aneurysmal SAH is affected by both the severity of the bleeding and the type of therapy.

Affect↗

PubMed2004

Endovascular treatment of cerebrovascular disease.

PURPOSE OF REVIEW: This review summarizes recent advances in endovascular therapy for cerebrovascular disease. RECENT FINDINGS: For ruptured aneurysms, the only large, randomized, controlled trial comparing surgical and endovascular treatment (the International Subarachnoid Aneurysm Trial) resulted in a significant reduction in death or dependency at 1 year, compared with surgery, providing sound evidence that coiling should be the treatment of first choice. Data from the International Study of Unruptured Intracranial Aneurysms demonstrated that treatment of unruptured anterior circulation aneurysms of under 7 mm with no history of subarachnoid hemorrhage is not justified. Embolization of arteriovenous malformations, as sole therapy, is curative only in a small percentage of cases, but can be part of a multimodal approach for reducing arteriovenous malformation size prior to surgery or radiotherapy. Partial treatment of complex arteriovenous malformations may be more dangerous than no treatment. Protection devices can reduce complication rates in carotid artery stenting, but scientific evidence is still lacking. Until the results of comparative trials are available, carotid artery stenting is indicated only in selected patients. Angioplasty and stenting of intracranial arterosclerotic disease is feasible but remains a high-risk procedure, indicated only in highly selected patients. In acute stroke therapy, new thrombolytics and clot-retrieval devices may result in better recanalization rates. SUMMARY: Advances in endovascular therapy have occurred in all areas of cerebrovascular disease. To obtain maximal patient benefit, endovascular treatment should be performed as an interdisciplinary approach in high-volume centers. Importantly, long-term follow-up review is necessary to clarify the overall role of endovascular treatment in the management of cerebrovascular disease.

Arteriovenous Malformations↗

PubMed2004

Double-stent method: therapeutic alternative for small wide-necked aneurysms. Technical note.

The authors present two cases of patients with small, acutely ruptured, wide-necked aneurysms of the distal vertebral artery that were not amenable to conventional coil embolization and were instead treated by means of a double-stent method in which one stent was placed inside another. Angiography performed immediately after the procedure revealed a significant reduction in aneurysm filling; total occlusion of the lesion was observed after 7 days and confirmed 6 months later in both aneurysms. By placing one stent inside the other, stent permeability can be reduced, which may result in significant hemodynamic changes with accelerated aneurysm thrombosis. This double-stent method may represent a therapeutic alternative, especially in cases of small, wide-necked aneurysms in which conventional endovascular techniques or stent-supported coil embolization is not considered feasible or is believed to be too dangerous, and surgical treatment is contra-indicated.

Cerebral Angiography↗

PubMed2003

Recurrent hemorrhage after initially complete occlusion of intracranial aneurysms.

Recurrent hemorrhage in the case of incompletely treated aneurysms is well known. The authors present a series of patients in whom rebleeding occurred in spite of totally occluded aneurysms. During a period of 12 years, 1170 patients with intracranial aneurysms were treated using either clipping (n=727) or coiling (n=443). In 11 of them, intracranial rebleeding occurred, in seven of whom routine post-treatment angiography revealed total aneurysm occlusion before the appearance of rehemorrhage. Further analysis focused on these seven patients. Their recurrent aneurysm ruptures happened with a mean latency of 9.5 months (range 21 h-48 months) from initial treatment. All aneurysms belonged to the anterior circulation. Three patients underwent primary clipping, and four experienced coiling first. The intracranial hemorrhages appeared mainly as intracerebral hematomas. The angiographically documented recurrent aneurysm configurations were caused by clip slippage (n=2), coil compaction (n=3), or coil migration/dislocation (n=1). In one case with primary surgery, clip slippage was possible but not confirmed by intraoperative view, because the patient died before therapeutic intervention. Two patients did not undergo therapy because of their poor clinical condition and died. Four of the remaining patients underwent clipping of the recurrent lesions, and one had recoiling. Final outcome was excellent/good in only two patients. The mainly poor outcome after rebleeding was caused by the high incidence of intracerebral hemorrhage.

Adult↗

PubMed2003

Elastin polymorphism haplotype and intracranial aneurysms are not associated in Central Europe.

BACKGROUND AND PURPOSE: The occurrence of intracranial aneurysms and of aneurysmal subarachnoid hemorrhage are influenced by genetic factors. Recent genomic studies in Japan have defined 3 chromosomal loci and 1 haplotype of elastin polymorphisms as important risk factors, both for affected sib pairs and sporadic patients. METHODS: We have genotyped 2 single nucleotide polymorphisms in the elastin gene and evaluated their allelic association with intracranial aneurysm in a Central European sample of 30 familial and 175 sporadic patients and 235 population controls. RESULTS: We found no allelic association between this elastin polymorphism haplotype and intracranial aneurysm. CONCLUSIONS: Our data probably reflect increased genetic heterogeneity of intracranial aneurysm in Europe compared with Japan.

Adult↗

PubMed2003

Funeral for a friend.

Explore the source record for details and available documents.

Angiography, Digital Subtraction↗

PubMed2002

Complementary management of partially occluded aneurysms by using surgical or endovascular therapy.

OBJECT: The authors present a series of patients in whom partially occluded aneurysms were retreated using complementary surgical or endovascular therapy. METHODS: During a period of 18 months, 301 patients with intracranial aneurysms were treated using either clip application (171 patients) or endovascular embolization with Guglielmi Detachable Coils ([GDCs] 130 patients). Routine posttreatment angiography studies revealed residual aneurysms in 21 of these patients, nine of whom were retreated using an endovascular or surgical method, with a mean treatment latency of 1.2 months. Four patients underwent primary surgical clip application, whereas five patients experienced GDC packing first. Among patients in the surgical group, the residual aneurysm neck was small and total elimination of the aneurysm was achieved by packing in GDCs. In patients in the endovascular group the authors incompletely packed the aneurysm because of its wide neck or fusiform component in two patients, perforation of a very small aneurysm in one patient, and coil dislocation in another patient. Typical coil compaction occurred in one case. Complete clip application was achieved in all patients. There was no complication in any patient due to the second treatment modality. Final outcome was excellent or good in six and fair in three. CONCLUSIONS: Following clip application or endovascular embolization of intracranial aneurysms, the use of complementary surgical or endovascular management is successful and associated with low morbidity.

Adolescent↗

PubMed2002

Endovascular treatment of unruptured intracranial aneurysms.

BACKGROUND AND PURPOSE: Intracranial aneurysms are common, with an overall frequency ranging from 0.8% to 10%. Because prognosis after subarachnoid hemorrhage is still very poor, treatment of unruptured aneurysms, either neurosurgically or endovascularly, has been advocated. However, risk of rupture and subsequent subarachnoid hemorrhage needs to be considered against the risks of elective treatment. We analyzed the technical feasibility, safety, and efficacy of endovascular treatment of a consecutive series of unruptured cerebral aneurysms. METHODS: From July 1997 through December 2000, a total of 76 patients with 82 unruptured cerebral aneurysms were treated at our institution. Endovascular treatment was administered to 39 consecutive patients with a total of 42 unruptured cerebral aneurysms. Thirty-six aneurysms were treated with an endovascular technique; in six patients, the parent artery was occluded to eliminate aneurysmal perfusion. Aneurysms were located either in the anterior (n = 31) or posterior (n = 11) circulation. Eight patients had experienced previous subarachnoid hemorrhage from other aneurysms and were treated electively after complete rehabilitation. Ten patients had neurologic symptoms; in 21 patients, the aneurysm was an incidental finding. Eighteen aneurysms were small (0-5 mm), 11 were medium (6-10 mm), nine were large (11-25 mm), and four were giant (> 25 mm). Occlusion rate was categorized as complete (100%), subtotal (95-99%), and incomplete (< 95%) obliteration. RESULTS: Endovascular treatment was technically feasible for 38 of 42 aneurysms. Complete (100%) or nearly complete (95-99%) occlusion was achieved in 34 of 38 aneurysms. In four aneurysms of the internal carotid artery, only incomplete (< 95%) occlusion was achieved. All patients except one with mild neurologic deficits according to the Glasgow Outcome Scale and one with mild memory dysfunction but no focal neurologic deficit achieved good recovery, resulting in a morbidity rate of 4.8% and a mortality rate of 0%. CONCLUSION: Endovascular embolization of unruptured cerebral aneurysms is an effective therapeutic alternative to neurosurgical clipping and is associated with low morbidity and mortality rates. For the management of unruptured aneurysms, endovascular treatment should be considered.

Adult↗