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Biomedical subjects

J Klisch

Publications and source records attributed to J Klisch.

At least 19 recordsLinked to original sources
PubMed2003

Head and neck vascular malformations: time-resolved MR projection angiography.

Extracranial vascular anomalies can be divided into haemangiomas and vascular malformations. The latter can be subdivided on the basis of the predominant type of vascular channels. Separation of high- and low-flow vascular malformations is of clinical importance. We report preliminary observations on time-resolved magnetic resonance projection angiography (MRPA) of vascular malformations of the head and neck. We examined eight patients with vascular anomalies of the head and neck. On MRPA the time between the early arterial phase and enhancement of the malformation could be used to distinguish high- and low-flow lesions. High-flow arteriovenous malformations showed early, intense enhancement. Venous malformations were either not visible on MRPA or showed late enhancement of veins. One patient was examined after embolisation of an arteriovenous fistula of the mandible. Normal MRPA was taken to indicate absence of a residual lesion.

Adolescent↗
PubMed2003

Activated clotting time or activated partial thromboplastin time as the method of choice for patients undergoing neuroradiological intervention.

We evaluated the role of the activated clotting time (ACT) and activated partial thromboplastin time (APTT), both currently available as bedside tests, for monitoring anticoagulation following bolus injection of 2500 or 5000 IU heparin in 21 patients undergoing neuroradiological procedures. APTT was measured using the CoaguChek Pro device compared to the laboratory standard measurement and ACT comparing CoaguChek Pro to Hemochron Celite and Kaolin. Statistical analysis was performed using Bablok-Passing regression. Despite heparin doses of 2500-5000 IU APTT measurements were out of range in 67% of patients using CoaguChek Pro and in 76.5% of patients using the laboratory measurement. ACT was reliably determined in all patients. The correlation between the different devices (CoaguChek Pro vs. Hemochron Celite r=0.69, Kaolin r=0.78) and assays (Hemochron Celite/Kaolin r=0.85) was good. ACT ranged from 141-417 s measured by CoaguChek Pro and 138-320 s measured by Hemochron Celite and 172-381 s using Hemochron Kaolin. These results indicate that ACT is the method of choice for monitoring anticoagulation in neuroangiographic procedures.

Female↗
PubMed2003

Arteriovenous malformation in the temporalis muscle.

An 18-year-old man presented with an arteriovenous malformation (AVM) in the temporalis muscle. It was shown by magnetic resonance imaging (MRI) and confirmed by intra-arterial angiography. The lesion was completely resected and the defect reconstructed with titanium mesh and cancellous bone.

Adolescent↗
PubMed2002

Determination of hemisphere dominance for language: comparison of frontal and temporal fMRI activation with intracarotid amytal testing.

The reliability of frontal and temporal fMRI activations for the determination of hemisphere language dominance was evaluated in comparison with intracarotid amytal testing (IAT). Twenty-two patients were studied by IAT (bilateral in 13, unilateral in 9 patients) and fMRI using a paradigm requiring semantic decisions. Global and regional (frontal and temporoparietal) lateralisation indices (LI) were calculated from the number of activated (r>0.4) voxels in both hemispheres. Frontolateral activations associated with the language task were seen in all patients, temporoparietal activations in 20 of 22. Regional LI corresponded better with IAT results than global LI. Frontolateral LI were consistent with IAT in all patients with bilateral IAT (including three patients with right dominant and one patient with bilateral language representation) and were not conflicting in any of the patients with unilateral IAT. Temporoparietal LI were discordant with IAT in two patients with atypical language representation. In the determination of hemisphere dominance for language, regional analysis of fMRI activation is superior to global analysis. In cases with clear-cut fMRI lateralisation, i.e. consistent lateralised activation of frontal and temporoparietal language zones, IAT may be unnecessary. FMRI should be performed prior to IAT in all patients going to be operated in brain regions potentially involved in language.

Adolescent↗
PubMed2002

Combined stent implantation and embolization with liquid 2-polyhydroxyethyl methacrylate for treatment of experimental canine wide-necked aneurysms.

The purpose of the study was the evaluation of 2-polyhydroxyethyl methacrylate (2-P-HEMA) for endovascular liquid embolization of experimental side-wall aneurysms following stent protection in a canine model. The swelling behaviour and polymerization characteristics of 2-P-HEMA in different solutions were investigated in vitro. Different methods for applications were tested in a latex aneurysm model under pulsatile flow conditions. Twenty broad-based carotid side-wall aneurysms were microsurgically produced in five dogs. Four weeks after surgery self-expandable nitinol stents were placed, covering the orifice of the aneurysms. 2-P-HEMA was injected via a microcatheter, which was positioned through the meshwork of the stent. Control angiography was performed immediately after treatment and after 1, 6 and 9 months. In-vivo stent placement succeeded in all but one case. Two aneurysms occluded spontaneously after stent placement. Combined embolization of 17 aneurysms using a stent and 2-P-HEMA was performed. Eleven aneurysms could be primarily completely occluded (65%). A small remaining neck was evident in six aneurysms. Efflux of 2-P-HEMA during the process of embolization was observed in seven aneurysms, due to an excess volume of 2-P-HEMA. The excessive 2-P-HEMA led to significant vessel stenosis in two cases. Two carotid arteries (three treated aneurysms) occluded after 1 month, due to insufficient anticoagulation management. Histological examination of embolized aneurysms revealed no foreign-body or inflammatory reaction. A smooth neo-intimal layer covered the stented vessel segment. Liquid embolization of side-wall aneurysms with 2-P-HEMA is technically feasible. Embolotherapy of aneurysms with liquid agents still has the risk that embolic material will exit even when it is stent-protected. To avoid this problem, stents with smaller strut diameter and/or additional balloon-protection are required. The inert 2-P-HEMA seems to be a promising agent for combining techniques of aneurysm treatment.

Aneurysm↗
PubMed2002

Paraneoplastic cerebellar degeneration and nephrotic syndrome preceding Hodgkin's disease: case report and review of the literature.

A patient presented with symptoms of cerebellar degeneration and nephrotic syndrome. A work-up at that time failed to reveal an underlying disease; however, 20 months later Hodgkin's disease was diagnosed. Hodgkin's lymphadenopathy developed 2 wk after prednisone therapy for the nephrotic syndrome had been discontinued. Systemic polychemotherapy resulted in complete remission of both Hodgkin's disease and nephrotic syndrome, while the neurological deficit persisted. Patients with unexplained cerebellar degeneration and/or nephrotic syndrome demand extensive evaluation for the presence of Hodgkin's disease, and steroid therapy may delay diagnosis.

Adrenal Cortex Hormones↗
PubMed2002

Latex aneurysms: a technical note.

We describe a new technique for manufacturing latex tubings with thin-walled aneurysms. The physical characteristics of the latex model with its compliance simulates important details such as shape, size, neck and the thin wall of an aneurysm. Therefore important aspects of neuroendovascular therapy could be simulated and investigated in-vitro.

Aneurysm↗
PubMed2002

Hyperglycemia in patients with focal cerebral ischemia after intravenous thrombolysis: influence on clinical outcome and infarct size.

The aim of the present prospective study was to investigate whether hyperglycemia influences the clinical outcome or the infarct size after intravenous thrombolysis of focal cerebral ischemia. A consecutive series of hyperglycemic (n = 14) and normoglycemic patients (n = 17) with acute focal cerebral ischemia (<3 h) in the middle cerebral artery (MCA) territory received rtPA (0.9 mg/kg body weight) intravenously. Clinical outcome was measured using the NIH Stroke Score on admission and was followed up until day 28. Infarct volume was measured by diffusion-weighted MR imaging on admission, on days 3 and 7. There was a significantly better neurological outcome on day 28 in the normoglycemic patients than in the hyperglycemic group (NIH SS 4.0 versus 7.4; p < 0.05). The infarction volume increased significantly in the hyperglycemic patients Delta = 39.9 plus minus 17.4% compared to normoglycemic patients Delta = 27.1 plus minus 14.1% (p < 0.05). The present study suggests that hyperglycemia in patients with a focal MCA ischemia can cause a worse clinical outcome despite recanalization of the occluded vessel by thrombolysis therapy. This correlates with a markedly larger increase of the infarction volume in the hyperglycemic group. These results may be explained by an accentuated lactate accumulation and pH decrease by elevated energy levels which cannot be compensated by restoration of blood flow alone.

Adolescent↗
PubMed2002

Calvarial sclerosing osteomyelitis.

We report a 15-year-old boy who suffered from calvarial sclerosing osteomyelitis and presented with painful head swelling. X-rays of the skull revealed areas of irregular radiolucency. MR imaging and CT showed a well-demarcated intradiploic lesion with thickening of the skull extending from the frontal to the parietal calvarium with a low signal on T1-weighted images, strong but heterogeneous enhancement after gadolinium application and a mixed signal on T2-weighted images. Computer-navigated neurosurgery was planned, and the craniotomy defect was reconstructed by a preformed titanium implant. Sclerosing osteomyelitis of the calvarium has to be included in the differential diagnosis of osteolytic and sclerosing lesions of the skull coinciding with persistent swelling of the head.

Adolescent↗
PubMed2001

Localization of interictal delta and epileptiform EEG activity associated with focal epileptogenic brain lesions.

The present study was aimed at investigating the accuracy of electric source reconstruction in the presurgical evaluation of epilepsy patients. Spontaneous EEG activity of 14 patients with focal intracerebral epileptogenic lesions was analyzed by source reconstruction based on high-resolution EEG (64-channel system) and a boundary element method head model accounting for the individual head anatomy. Equivalent dipole modeling was applied to focal delta and interictal epileptiform activity. The localization results were validated quantitatively by comparison with the sites of the structural lesions. In 6 of 9 patients with focal delta activity, the maximum of dipole concentration was closer than 10 mm to the nearest lesion margin and mostly at the border or within pathologically altered cortical tissue. In all 11 patients showing interictal epileptiform activity, the localization results were found in the same lobe as the lesion. In almost half of them, they were closer than 10 mm to the lesion margin. Patients with larger distances (22-36 mm) mostly had hippocampal atrophy or sclerosis. Their dipole locations did not appear in the affected hippocampus, but in the adjacent temporal neocortex. In conclusion, electric source reconstruction applied to both abnormal slow and interictal epileptiform EEG activity seems to be a valuable additional noninvasive component in the multimodal presurgical evaluation of epilepsy patients.

Adult↗
PubMed2001

The two-in-one model: a new variation of the arteriovenous malformation model in swine.

We report a new variation of the well-established experimental arteriovenous malformation (AVM) model in swine. To provide high flow through the rete mirabile (nidus, RM) and thereby to reduce the rate of spontaneous thrombosis of the AVM, we performed an end-to-end anastomosis of the left common carotid artery (CCA) and the external jugular vein (EJV) microsurgically in three micropigs. After 1 and 4 months the animals underwent angiograms of the CCA and vertebral artery (VA). In all cases the diversion of the blood through the RM was patent, up to the 4 months follow-up. We observed an arteriovenous fistula (arteriovenous pseudomalformation, pAVF) between the VA and the EJV in each case at both 1 and 4 months. This modification of the well-known AVM model in the micropig could be used to monitor long-term changes after embolisation, avoiding the naturally high rate of spontaneous thrombosis. This two-in-one model is thus well suited for preclinical testing of embolic materials.

Animals↗
PubMed2001

Transsphenoidal computer-navigation-assisted deflation of a balloon after endovascular occlusion of a direct carotid cavernous sinus fistula.

SUMMARY: A 49-year-old woman with a direct posttraumatic carotid cavernous fistula (CCF) was treated with detachable balloons via a transcarotid route. After the procedure, her intracranial bruit, conjunctival injection, and orbital congestion were cured, but the preexistent sixth nerve palsy deteriorated. CT showed one balloon positioned in the posterior portion of the right cavernous sinus and was regarded to be responsible for nerve compression. After surgical exposure by use of a transnasal-transsphenoidal approach under 3D navigation control, this balloon was deflated by puncture with a 22-gauge needle. The previously described symptoms resolved after balloon deflation. This report presents a rare complication of endovascular treatment of direct CCF and a new microsurgical approach to a balloon in a case of nerve compression.

Abducens Nerve Diseases↗
PubMed2001

Lhermitte-Duclos disease: assessment with MR imaging, positron emission tomography, single-photon emission CT, and MR spectroscopy.

SUMMARY: Lhermitte-Duclos disease (LDD) is a rare cerebellar lesion with features of both malformation and benign neoplasm. However, the fundamental nature of the entity, its pathogenesis, and the exact genetic alterations remain unknown. We describe MR findings (including perfusion- and diffusion-weighted images) in two patients with LDD, as well as findings from single-photon emission CT (SPECT), MR spectroscopy (MRS), and fluorodeoxyglucose (FDG) positron emission tomography (PET) that give additional information about tumor pathophysiology. MR imaging usually distinguishes the LDD by its characteristic "tiger-striped" appearance. The regions of increased regional cerebral blood volume (rCBV) within the lesion correlated closely to the regions of FDG-hypermetabolism and high thallium (201-Tl) uptake. Proton MRS revealed an increased level of lactate and decreased level of myo-inositiol and N-acetyl-aspartate, as observed in low-grade gliomas, but decreased levels of choline. Our cases indicate that the functional investigations give additional information about tumor pathophysiology and reflect the histopathologic controversial entity with both characteristics found in low-grade gliomas and characteristics not typical for tumors.

Adult↗
PubMed2000

Fast functional MRA using time-resolved projection MR angiography with correlation analysis.

Most recently, time-resolved 2D MRA after injection of a contrast agent bolus for various applications has been proposed. Similar to conventional digital subtraction angiography (DSA), 2D MR DSA offers the ability to observe the dilution of the bolus in the vascular system during the passage with a temporal resolution considerably below 1 sec. The purpose of this paper is to present strategies to improve the inherent low signal-to-noise ratio of 2D angiograms while retaining some temporal resolution. This can be achieved by applying algorithms for time series analysis as used in functional MRI. The significantly improved image quality is demonstrated on examples from clinical studies from bronchial MRA as well as cardiovascular MRA. In addition to the increased signal-to-noise ratio, correlation analysis leads to suppression of background signals and to a better discrimination of overlapping vessels. Further improvements in the temporal discrimination of vessels is afforded by the use of consecutive multiple contrast agent boli as demonstrated by numerical simulations and experiments.

Artifacts↗
PubMed2000

Supratentorial primitive neuroectodermal tumours: diffusion-weighted MRI.

We report the clinical and pathological findings of supratentorial primitive neuroectodermal tumours (PNETs). These are rare, poorly differentiated, highly malignant neoplasms occurring primarily in young individuals. They frequently show dissemination to the spinal cord and sometimes also beyond neuraxis. Preoperative radiological diagnosis is difficult, due to the nonspecific CT and MRI characteristics. Our findings indicate that diffusion-weighted imaging (DWI) can be used to show the solid portion of the tumour preoperatively and to monitor postsurgical recovery. We describe the MRI findings in three patients with histologically confirmed supratentorial PNET, focussing on the role of DWI for improving the specificity of radiological diagnosis.

Child↗
PubMed2000

Time-resolved projection MRA: clinical application in intracranial vascular malformations.

We report preliminary results of imaging intracranial vascular malformations with time-resolved projection MRA after a bolus injection of contrast median before and after endovascular treatment. Projection angiograms are acquired with a slice-selective snapshot FLASH sequence with a time resolution of two images per second, 40-60 images being acquired consecutively after bolus injection of 15 ml Gd-DTPA. Postprocessing of images in 2D projection MRA by correlation analysis offers several advantages with significant improvement of signal-to-noise, leading to adequate anatomical resolution. Subsecond projection MRA is a reliable technique for imaging intracranial vessels and gives information about the haemodynamics of vascular malformations.

Angiography, Digital Subtraction↗