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O Jansen

Publications and source records attributed to O Jansen.

At least 73 records · Page 4Linked to original sources
PubMed1998

Neuroradiological findings in adult cranially conjoined twins. Case report.

The authors demonstrate the radiological anatomy and review the accepted embryological theories in a case of total craniopagus. These 24-year-old female cranially conjoined twins were studied with computerized tomography (CT) and CT angiography, magnetic resonance (MR) imaging and MR angiography as well as selective arterial digital subtraction (DS) angiography to clarify whether surgical separation was possible. The neuroradiological findings are discussed, taking into consideration both the embryological and surgical literature. The malformation was classified as a total parietooccipitotemporal craniopagus. Whereas CT angiography and MR imaging including MR angiography demonstrated a common superior sagittal sinus, only selective arterial DS angiography revealed a significant arterial and venous cross-flow between the two adjacent temporal lobes. Selective intraarterial DS angiography is required in the neuroradiological evaluation of complex malformations, even when the anatomy of brain and skull can be well demonstrated with high-quality MR and CT studies.

Adult↗
PubMed1998

[CT angiography to determine the size of intracranial aneurysms before GDC therapy].

OBJECTIVE: To examine in a model and in clinical practice whether CT angiography (CTA) is suitable to determine the size of intracranial aneurysms. METHODS: For an aneurysm model the contrast medium-filled balloon of an occlusion catheter was used. At different levels of filling images were obtained by both CTA and digital subtraction angiography (DSA). In the CT image the size of the simulated aneurysm was calculated from the CTA data at the workstation while from the DSA images it was performed by the DSA system with the use of both an external reference structure (two-ring method) and a stereotactic system (ANGIOLOG). In 7 patients, the size of the aneurysm was determined by CTA and DSA prior to aneurysm occlusion by means of guglielmi detachable coils (GDC therapy). RESULTS: On the basis of 2 D reconstructions of the CT average size deviations in the XY plane of 1.6% and on the Z axis of 3.2% were determined. These errors increased to 3.4% (XY plane) and 5.6% (Z axis) with 3 D reconstructions. By use of the two-ring model, DSA gave an average size deviation of 3% while with the stereotactic system (ANGIOLOG) it was as high as 11%. In 6 of the 7 patients, the appropriate spiral size was chosen primarily after CTA measurements. CONCLUSIONS: CTA enables the reliable determination of the size of an intracranial arterial aneurysm and in individual cases can give a better representation of an anatomic situation at the base of an aneurysm than DSA. Thus, CTA imaging of an aneurysm prior to GDC therapy is useful.

Adult↗
PubMed1997

Image guided excision of a ruptured feeding artery "pedicle aneurysm" associated with an arteriovenous malformation in a child: case report.

Excision of a ruptured aneurysm located at a lenticulostriate feeding artery associated with an arteriovenous malformation was performed using image guided neuronavigation in an 8-year-old child. The management of this lesion, which is rare in childhood, demonstrates the potential of combining frameless stereotaxy for precise target approach with conventional open microneurosurgery to minimize morbidity. Because of the unavoidable shifting of the brain that occurs during surgery, a catheter pointing towards the dome of the aneurysm was placed using image guidance prior to insertion of spatulae.

Aneurysm, Ruptured↗
PubMed1997

MRI findings in chronic hepatic encephalopathy depend on portosystemic shunt: results of a controlled prospective clinical investigation.

BACKGROUND/AIMS: Deterioration of hepatic encephalopathy is a major concern with the transjugular intrahepatic portosystemic shunt procedure. Symmetric hyperintense globus pallidus on T1-weighted cranial magnetic resonance imaging in patients with liver cirrhosis anticipates hepatocerebral disease. It is hypothesized that hepatic encephalopathy and basal ganglia signal intensity progress in patients with cirrhosis of the liver undergoing transjugular intrahepatic portosystemic shunt. METHODS: Twenty-four patients were randomized to undergo either transjugular intrahepatic portosystemic shunt or elective sclerotherapy. At study entry and 6 months after randomization, neurologic assessment, psychometric tests, standard EEG, and magnetic resonance imaging were performed. The severity of liver failure was graded using Child-Pugh's classification. The signal intensity of the globus pallidus was determined on sagittal T1-weighted magnetic resonance imaging. RESULTS: The T1-weighted signal intensity of the globus pallidus on magnetic resonance imaging significantly increased after transjugular intrahepatic portosystemic shunt placement (p<0.01), but not with elective sclerotherapy. At follow-up, neurological symptoms indicating decline of mental status and motor performance were somewhat more prevalent in transjugular intrahepatic portosystemic shunt patients. Significant deterioration of EEG abnormalities occurred in patients treated with transjugular intrahepatic portosystemic shunt as opposed to elective sclerotherapy (p<0.01). CONCLUSIONS: Transjugular intrahepatic portosystemic shunt procedure increases hyperresonant globus pallidus on magnetic resonance imaging. Neuropsychiatric evaluation shows advancing hepatic encephalopathy, in particular with transjugular intrahepatic portosystemic shunt; however, it does not parallel the augmentation of pallidal signal intensity on magnetic resonance imaging.

Adult↗
PubMed1997

Muscular involvement in the Holt-Oram syndrome.

Holt-Oram syndrome is an autosomal dominant disorder characterised by radial ray and congenital heart defects. Recently, a gene for this disorder has been identified on chromosome 12q24.1, encoding a T box transcription factor. However, the functional role of the gene product is not completely understood. We present results of neurological, radiological, and muscle magnetic resonance imaging (MRI) investigations in 13 patients from eight unrelated families. Besides heart defects, clinical signs ranged from thenar abnormalities to bilateral phocomelia. The former were present in all patients. MRI showed hypoplasia of discrete muscles which clinically showed as non-progressive weakness. The structural pattern of residual muscles was normal on MRI, which together with normal muscular power, electromyography, and muscle enzyme investigations excluded a progressive neuromuscular disorder. The number and location of hypoplastic muscles correlated with the severity of skeletal involvement. Thus, patients with hypoplasia of large and proximal muscles had phocomelia, and those with mere intrinsic hand muscle hypoplasia had only a triphalangeal thumb or no skeletal malformation. On the basis of these observations, we conclude that disturbed fetal limb muscle development is involved in the bony malformations of the upper limbs.

Adult↗
PubMed1997

Proximal myotonic myopathy with MRI white matter abnormalities of the brain.

Proximal myotonic myopathy (PROMM) is an autosomal dominantly inherited multisystemic disorder characterized by myotonia, proximal muscle weakness, and cataracts. This disorder is not linked to the gene locus of myotonic dystrophy (DM). We describe three new families with PROMM. In all patients, CTG repeats of the DM gene in DNA from blood leukocytes were normal. MRI of the brain revealed a consistent pattern of marked white matter hyperintensity on T2-weighted images in four patients; two additional patients had similar but mild to moderate MRI abnormalities. The morphology of these abnormalities is unknown. Clinical symptoms of brain disease were not consistent and included mental changes with hypersomnia, parkinsonian features, stroke-like episodes, and seizures. The causative relationship of these clinical features with the MRI white matter abnormalities remains to be established. Our observations suggest that PROMM may involve the brain.

Adult↗
PubMed1996

[CT angiography in dissections of the internal carotid artery. Value of a new examination technique in comparison with DSA and Doppler ultrasound].

PURPOSE: To evaluate the role of CT angiography (CTA) in the diagnosis of dissection of the internal carotid artery (ICA). METHODS: In 21 patients who were clinically or sonographically suspected of having a dissection of the ICA, we performed CTA covering the extracranial course of the ICA. Our technique included spiral scanning (Picker PQ 2000), slice thickness 3 mm, index 1.5 mm, pitch factor 1.25, tube voltage 130 kV, amperage 125 mA, i.v. bolus injection of 100 ml nonionic contrast medium, injection rate 4 ml/s and scan delay 15 s. Spiral data were processed using a workstation (Picker Voxel Q) to calculate 3D "angiographic" reconstructions, maximal intensity projections and multiplanar reconstructions. In 20 of the 21 patients transfemoral angiography was performed, and in all patients cw-Doppler ultrasonography of the carotid arteries was performed. RESULTS: Sensitivity of CTA in acute extracranial dissection of the ICA was 100% (14/14). One patient had a pseudoaneurysm of the ICA, two patients had excessive kinking and one patient showed an atheromatous carotid ulcer. DSA could confirm this in all cases. One intracranial ICA dissection, not covered by the scan field, was missed by CTA. CTA source images demonstrated mural thickening and eccentric luminal narrowing in cases of dissection. 3D reconstructions showed tapering of the ICA. CONCLUSION: CTA is a reliable tool in the diagnosis of ICA dissection. Further studies comparing CTA, MRI and duplex ultrasound are necessary.

Aortic Dissection↗
PubMed1996

Neuropsychiatric profile and hyperintense globus pallidus on T1-weighted magnetic resonance images in liver cirrhosis.

BACKGROUND & AIMS: Hyperintense globus pallidus on T1-weighted magnetic resonance images (MRIs) in cirrhotic patients are reported to reflect severity of liver disease; however, their consequence for hepatic encephalopathy is unknown. The aim of this study was to outline a pattern of neuropsychiatric abnormalities in chronic liver failure and its correlation with MRI findings. METHODS: Fifty-one consecutive patients were enrolled in the study. Neuropsychiatric assessment used a standardized protocol, including dichotomized neurological parameters, brief psychiatric rating and psychometric tests, as well as electroencephalography. The severity of liver failure was graded using standard laboratory parameters and the Child-Pugh's classification. Signal intensity of the globus pallidus was determined on sagittal T1-weighted MRIs. RESULTS: Two aspects of neurological dysfunction could be distinguished by principal components analysis: impairment of complex cerebral function and subcortical motor performance. Both neurological categories correlated with severity of liver failure, grade of electroencephalographic abnormalities, and psychometric test results. Additionally, prior bouts of overt encephalopathy indicate progressive dementia. T1-weighted globus pallidus signal intensity did not correlate with any clinical or laboratory test result. CONCLUSIONS: This study shows a characteristic pattern of neurological findings in patients with liver failure and hyperintense globus pallidus on T1-weighted MRIs. Although neurological dysfunction parallels hepatic failure, MRI abnormalities of basal ganglia do not indicate severity of actual hepatic encephalopathy.

Adolescent↗
PubMed1996

[Does the administration of a high dose of a paramagnetic contrast medium (Gadovist) improve the diagnostic value of magnetic resonance tomography in glioblastomas?].

PURPOSE: To assess the efficacy of high-dose contrast enhanced magnetic resonance imaging (MRI) in detection and delineation of infiltrating tumour in glioblastoma. MATERIAL AND METHODS: In a phase II clinical trial 14 patients with suspected supratentorial glioblastoma underwent MRI with Gd-DO3A-butriol (Gadovist, Schering AG, Berlin) with doses of 0.1 up to 0.3 mmol/kg. RESULTS: Increasing the dose of Gd-DO3A-butriol resulted in improved enhancement (14/14) and better delineation of infiltrating tumour (9/14) up to 2 cm beyond enhancement after standard dose. In two of the 9 patients additional enhancement in the peritumoural oedema was only seen after the third injection. CONCLUSIONS: Successful surgery requires precise preoperative delineation of tumour borders. After high-dose MRI it might be possible to select those patients who would benefit from more radical attempts at eradicating the macroscopic as well as most of the microscopic compartment of glioblastoma.

Contrast Media↗
PubMed1996

[Magnetic resonance tomography of vasogenic brain edema in animal experiments].

PURPOSE: To systematically evaluate modern magnetic resonance imaging (MRI) techniques of studying brain oedema, an animal model of vasogenic oedema is needed. MATERIAL AND METHODS: We developed such a model by stereotactically cannulating the caudate nucleus in 11 Wistar-rats and infusing a solution of albumin. The way the oedema developed was imaged by MRI and then correlated histologically (three animals) and macroscopically after infusion of Evans' blue (two animals). RESULTS: The extension of the infusion oedema was the same in both MRI and histology as well as at direct inspection of the specimen after infusion of Evans blue. With continuous acquisition of T1-weighted images after infusion of a 1% solution of Gd-DTPA we were able to demonstrate the dynamics of oedema evolution and bulk flow. CONCLUSION: We believe that this infusion oedema is a suitable model for systematically investigating both signal behaviour and pathogenesis of vasogenic brain oedema by MRI.

Animals↗
PubMed1996

[CT angiography of the cerebral veins].

PURPOSE: We report on our first experience in imaging the cerebral veins and sinuses with CT angiography (CTA). MATERIAL AND METHODS: CTA was performed in 10 patients after bolus injection of contrast medium to rule out sinus thrombosis. RESULTS: In 8 of 10 patients thrombosis of cerebral venous sinuses was ruled out by CTA. Sinus thrombosis was diagnosed and confirmed in two patients. In 5 cases, diagnosis of CTA was confirmed by MRI and/or DSA, in 5 other cases by the clinical course. CTA results in detailed information about flow and anatomy of cerebral veins due to high intravascular contrast. CONCLUSIONS: CTA is a suitable noninvasive method to study cerebral veins as it is superior to conventional CT because of high resolution and intravascular contrast. To assess the sensitivity of CTA for diagnosis of venous sinus thrombosis a prospective study is needed.

Adolescent↗
PubMed1996

Coil placement after clipping: endovascular treatment of incompletely clipped cerebral aneurysms. Report of two cases.

In up to 4% of patients whose aneurysms are microsurgically clipped, there is an expected or unexpected aneurysm residuum. The authors describe two patients in whom surgical clipping did not result in complete obliteration of the aneurysm sac and in whom a second operation was not believed to be the solution to the problem. In both patients complete occlusion of the aneurysm residuum was achieved via an endovascular approach. Using the Guglielmi detachable coil system, it was possible to place two platinum coils selectively into the aneurysms. The endovascular approach may be a good treatment option for all patients in whom surgical clipping does not result in complete obliteration of the aneurysm sac and reoperation is contraindicated or unacceptable to the patient.

Adult↗
PubMed1996

Interobserver agreement in assessing early CT signs of middle cerebral artery infarction.

PURPOSE: To assess the reliability of detecting signs of hemispheric infarction on CT scans obtained within 6 hours of the onset of symptoms. METHODS: A neuroradiologist selected 12 normal and 33 abnormal CT studies showing the hyperdense middle cerebral artery sign (HMCAS) (n = 10), brain swelling (n = 22), and parenchymal hypodensity (n = 33) from two series of 750 patients with recent onset of middle cerebral artery stroke. These selections served as the reference source for a nonblinded analysis of the initial and follow-up CT scans. Six neuroradiologists then reviewed the CT scans twice, first blinded then not blinded to clinical symptoms. They assessed the signs of infarction for each hemisphere separately and estimated the volume of abnormal parenchymal hypodensity in increments of 20% within the territory of the middle cerebral artery. RESULTS: Unblinding the reviewers did not change interobserver agreement significantly. The chance adjusted agreement was moderate to substantial: kappa = .62 (95% confidence interval [CI], .46 to .78) and kappa = .57 (95% CI, .33 to .81) for the HMCAS of the right and left hemisphere, respectively; kappa = .59 (95% CI, .47 to .71) and kappa = .56 (95% CI, .38 to .74) for focal brain swelling of the right and left hemisphere, respectively; and kappa = .58 (95% CI, .50 to .66) and kappa = .55 (95% CI, .32 to .67) for parenchymal hypodensity of the right and left hemisphere, respectively. Weighted kappa was .65 and .57 for the estimation of the hypodense tissue volume in the right and left hemisphere, respectively. Agreement with the reference source ranged from 73% to 93% for all variables and both hemispheres. CONCLUSION: Even with no clinical information, neuroradiologists can assess subtle CT signs of cerebral infarction within the first 6 hours of symptom onset with moderate to substantial interobserver agreement.

Brain Edema↗
PubMed1996

Cortical hyperintensity on proton density-weighted images: An MR sign of cyclosporine-related encephalopathy.

PURPOSE: To describe cortical hyperintensities in proton density-weighted images in six patients with presumed cyclosporine-induced neurotoxicity. METHODS: In six patients with clinical evidence of cyclosporine-related encephalopathy, MR imaging was performed after the onset of symptoms and signs (mean, 24 days after liver transplantation). Five of these patients had serial MR imaging for a period that varied from 2 to 20 months. Along with the imaging studies, the patients' clinical status was evaluated and various laboratory parameters, including blood pressure and levels of cyclosporine, cholesterol, and magnesium, were monitored. RESULTS: In all six patients, initial MR studies showed hyperintensity of several cerebral gyri that was unequivocal only on proton density-weighted images. Although in five patients these signal abnormalities were limited to the cortex, one patient had increased signal in the subjacent white matter as well. In one patient, the images were also remarkable for areas of cortical hyperintensities on T1-weighted images. In another patient, cortical enhancement occurred after administration of gadopentetate dimeglumine, with a normal cortical signal on the precontrast images. The abnormal cortical signal began to fade after cyclosporine reduction, but in two patients it remained visible for at least 20 months. The neurologic symptomatology associated with cyclosporine-induced neurotoxicity included seizures (three patients), speech disorder (three patients), and disturbance of consciousness (three patients). CONCLUSION: Cyclosporine-induced neurotoxicity occurring in patients after liver transplantation appears to affect the cerebral cortex preferentially. Because its MR equivalent resembles changes resulting from hypoxic injury or cortically centered vasculitis, we suspect the underlying mechanism may be a vascular injury that results in cortical hypoperfusion.

Adolescent↗
PubMed1995

Manganese and chronic hepatic encephalopathy.

Clinical observations and animal studies have raised the hypothesis that increased concentrations of manganese (Mn) in whole blood might lead to accumulation of this metal within the basal ganglia in patients with end-stage liver disease. We studied ten patients with liver failure (and ten controls) by magnetic resonance imaging (MRI) and measurement of Mn in brain tissue of three patients who died of progressive liver failure (and three controls) was also done. Whole blood Mn concentrations in patients with liver cirrhosis were significantly increased (median 34.4 micrograms/L vs 10.3 micrograms/L in controls; p = 0.0004) and pallidal signal intensity indices correlated with blood Mn (Rs = 0.8, p = 0.0058). Brain tissue samples reveal highest Mn concentrations in the caudate nucleus, followed by the quadrigeminal plate and globus pallidus. Mn accumulates within the basal ganglia in liver cirrhosis. Similarities between Mn neurotoxicity and chronic hepatic encephalopathy suggest that this metal may have a role in the pathogenesis of chronic hepatic encephalopathy. Further studies are warranted because the use of chelating agents could prove to be a new therapeutic option to prevent or reverse this neuropsychiatric syndrome.

Adult↗
PubMed1995

[Value of spiral CT in the diagnosis of nasolacrimal duct stenosis].

PURPOSE: This study was to evaluate postdacryocystographic spiral CT in the diagnosis of stenoses of the nasolacrimal duct system. PATIENTS AND METHODS: Dacryocystography and postdacryocystographic spiral CT were performed in 11 patients with epiphora. RESULTS: Postdacryocystographic spiral CT results in detailed information about the nasolacrimal duct system. Localization, degree, and aetiology of stenoses can be determined more reliably than with dacryocystography alone. CONCLUSION: Postdacryocystographic spiral CT improves planning surgical or radiological interventions such as balloon dacryocystoplasty of the nasolacrimal duct.

Adult↗
PubMed1995

[Neuroradiologic findings in arterial cerebral ischemia].

New therapeutical approaches require neuroradiological description of cerebral infarcts under pathogenetical aspects. Knowledge of the pathophysiological concepts of arterial cerebral vessel disease is necessary. These concepts are described in the first part of this paper. The relation between neuropathologic and radiologic findings and the different patterns and pathomechanisms or cerebral infarction are reported. In the second part of this paper typical CT- and MRI-findings are described and the differential diagnosis of cerebral infarcts are discussed.

Brain↗