PubMed Health⌕ Search

Biomedical subjects

B Schuknecht

Publications and source records attributed to B Schuknecht.

At least 37 records · Page 2Linked to original sources
PubMed1998

Improvement of cerebral oxygenation patterns and metabolic validation of superselective intraarterial infusion of papaverine for the treatment of cerebral vasospasm.

OBJECT: The purpose of the present study was to assess cerebral oxygenation patterns and brain lactate concentration changes before, during, and after intraarterial infusion of papaverine with or without balloon angioplasty in patients with symptomatic vasospasm. METHODS: A total of 23 vascular territories were successfully treated in 10 patients. In three patients balloon angioplasty was performed before the papaverine infusion. Continuous monitoring of jugular bulb vein oxygen saturation with a fiberoptic catheter and blood sampling allowed the assessment of the cerebral arteriovenous oxygen and lactate differences. A significant and rapid improvement in jugular bulb oxygen saturation was observed in all cases, with critical values reflecting an improvement in cerebral oxygenation after endovascular treatment of vasospasm (p = 0.005). Lactate concentration in the jugular bulb normalized within 4 hours in all patients who had evidence of brain lactic acidosis before superselective intraarterial infusion of papaverine. Recurrence of abnormal metabolic and oxygenation patterns were observed in one case in which an optimal hypertension and hypervolemic therapy could not be achieved after the procedure. CONCLUSIONS: Improvement in cerebral oxygenation as well as prevention of cerebral lactic acidosis can be successfully achieved after intraarterial infusion of papaverine. Normalization of the oxygen supply after endovascular treatment has to be supported by optimal and well-monitored hypertension and hypervolemic hemodilution.

Acidosis, Lactic↗
PubMed1998

Tributary venosinus occlusion and septic cavernous sinus thrombosis: CT and MR findings.

PURPOSE: In autopsy reports of patients who died of septic cavernous sinus thrombosis, tributary venosinus occlusion has been a common finding related to intracranial inflammatory complications. The purpose of this article is to illustrate the MR and CT appearance of septic cavernous sinus thrombosis and tributary venous occlusion. METHODS: Over a period of 7 years, eight patients with septic cavernous sinus thrombosis were examined by contrast-enhanced thin-section CT. The CT scans of these eight patients and those of 30 healthy control subjects were assessed independently and subjectively by two blinded readers to ascertain the presence, size, and density of areas of nonopacification within the cavernous sinus and the presence of filling defects and dilation of tributary veins and venous sinuses. In six subjects, MR images supplemented by a contrast-enhanced spoiled gradient-recalled acquisition in the steady state (SPGR) sequence were assessed with respect to the presence of filling defects, expansion, and signal abnormalities within the cavernous sinus and tributary veins and sinuses. The MR and CT findings were compared. RESULTS: The CT studies of the eight patients were consistently differentiated from those of the control subjects by the two readers. Contrast-enhanced CT findings in patients included areas of nonopacification that were present within the cavernous sinus bilaterally in six cases and unilaterally in two. The size of the filling defects exceeded 7 mm in 76% of thrombosed cavernous sinuses compared with 9% of control subjects. The mean density of filling defects in patients differed significantly from those in control subjects. Comparison of the MR and CT findings in six cases showed the contrast-enhanced SPGR sequence to be equivalent to CT with respect to delineation of filling defects. CONCLUSION: Contrast-enhanced high-resolution CT findings indicate that venosinus thrombosis associated with septic cavernous sinus thrombosis is not restricted to the superior ophthalmic vein and is more common than previously assumed. A contrast-enhanced SPGR MR sequence may be used as a reliable alternative to establish the diagnosis of cavernous sinus and tributary venosinus thrombosis.

Adolescent↗
PubMed1998

Transcranial color-coded Doppler sonography of intracranial aneurysms before and after endovascular occlusion with Guglielmi detachable coils.

BACKGROUND AND PURPOSE: Our purpose was to evaluate the ability of transcranial color-coded Doppler sonography (TCCD) to 1) identify Guglielmi detachable coils (GDCs) within intracranial aneurysms, 2) show endovascular aneurysmal occlusion and patency of parent and branch arteries, 3) determine the flow velocities within parent arteries and major branches before and after treatment, and 4) assess persistence of aneurysmal occlusion. METHODS: The sonographic appearance of GDCs was established experimentally by TCCD (2 to 2.5 MHz), which was then performed in 40 patients with 43 aneurysms occluded by GDCs. The patency of parent arteries and major branches was assessed qualitatively and compared with the immediate posttherapeutic angiographic appearance in every patient. Flow velocities were selectively measured and compared before and after treatment in 21 parent arteries and 24 major branches. Follow-up TCCD studies performed in 26 patients were compared with angiographic (16 cases) and MR angiographic (10 cases) findings for signs of recanalization of the treated aneurysms. RESULTS: The GDCs were identified experimentally and in the patients as hyperechoic structures of the size and shape, and in the location of, the treated aneurysm in 41 of 43 cases. TCCD in accordance with angiography showed a lack of flow in 42 aneurysms and the presence of flow signal in one large aneurysm. Patency of the parent artery was shown in 40 aneurysms and in all branches. Follow-up TCCD showed the coils unchanged in 23 of 26 cases. In three large aneurysms, TCCD indicated recanalization and reappearance of a flow signal separate from the parent artery. CONCLUSION: TCCD is a reliable, noninvasive means to assess parent artery and major branch patency and to reveal a lack of hemodynamic compromise in the vicinity of aneurysms after endovascular therapy. On follow-up examinations, TCCD was able to detect signs of aneurysmal recanalization.

Adolescent↗
PubMed1997

[Computerized tomography of paranasal sinuses--a preoperative check list].

BACKGROUND: Computed tomography (CT) is being used increasingly both to evaluate location and extent of sinus disease and to detect anatomic abnormalities prior to surgery. Analysis of the CT scan should be undertaken in a routine, standardized fashion to ensure that important details are not missed. To aid in this evaluation, a checklist has been developed which focuses on the most salient and potentially dangerous areas of the paranasal sinuses. Regular preoperative analysis using this system may prevent unforeseen technical difficulties and excess morbidity. MATERIALS AND METHODS: Before obtaining a CT scan, the patient is placed on optimal medical therapy including antibiotics, and topical and occasionally systemic steroids. Coronal scans are then performed with 3 mm sections through the frontal and sphenoid sinuses and 2 mm sections through the ethmoid region. Intravenous contrast is used. The study is then analyzed focusing on specific critical anatomic landmarks. When additional information is required due to severe pathology or atypical anatomy, axial sections are added. RESULTS: Out of 300 CT examinations that where analyzed, a preoperative checklist was developed with eight items that must be evaluated preoperatively. Methods for the identification and analysis of this anatomy as well as the types of anatomic variation are discussed. We have found this evaluation to be extremely useful and efficacious in preventing morbidity in endoscopic sinus surgery. CONCLUSIONS: Evaluation of the preoperative CT examination with a strictly applied checklist of important details and landmarks allows the recognition of hazardous anatomy and pathology which should increase the safety and efficacy of paranasal sinus surgery.

Chronic Disease↗
PubMed1997

[Experiences with assessment of frontobasal defects, a diagnostic concept].

BACKGROUND: Cerebrospinal fluid (CSF) rhinorrhea presents not only a therapeutic challenge, but a diagnostic challenge as well. This is especially true in the case of atraumatic spontaneous leakage, which is often only minimal in quantity and can occur intermittently. The purpose of this paper is to compare the current methods of evaluation of CSF Rhinorrhea (beta 2-Transferrin assay, high resolution computed tomography [HRCT], and computotomographic cisternography [CTC]) and develop a diagnostic protocol. METHOD: A retrospective analysis was performed of 61 patients who underwent operation for CSF rhinorrhea between 1988 and 1996 comparing the method of preoperative diagnosis and intraoperative findings. RESULTS: beta 2-transferrin-determination in the nasal discharge had a sensitivity of 79% (33/42), HRCT correctly identified the defect in 84% (48/57) of cases, and CTC correctly localized the pathology in 72% (18/25) of the patients. CONCLUSION: The sensitivity of each CSF rhinorrhea diagnosis method is less than 90%. It is our opinion that with the current level of technology a combined approach is optimal with two or more of the above studies. A diagnosis scheme is presented to manage step by step this challenging and potentially lethal problem.

Adolescent↗
PubMed1996

CT assessment of orbital volume in late post-traumatic enophthalmos.

The potential of CT to facilitate preoperative planning of reconstructive maxillofacial surgery by orbital volume quantification was analysed in 11 patients with traumatic enophthalmos as a late sequela of zygomatic fractures. We carried out biplanar CT examination of the orbits, and calculated total orbital and fat volumes for the healthy and enophthalmic sides. Displacement of the orbital floor and lateral wall was present in 11 and 7 cases respectively. Indentation of the medial wall was noted in 9 cases. Quantitative evaluation of the orbital cavity revealed a significant increase (P < 0.0188) in total volume on the enophthalmic side, the difference between the two sides ranging from 9.2% to 36.4%, mean 17.9%. The degree of enophthalmos, measured radiologically as 2.5-5 mm, correlated with the increase in orbital cavity volume (P = 0.000076). Enophthalmos was 2.5-3 mm in 7 cases (63.6%) and 3.5-5 mm in 4 (36.4%). This corresponded with a mean increase in orbital volume of 3.4 ml (12.3%) and 7.1 ml (27.8%) respectively. Fat atrophy was not an aetiological factor in the production of post-traumatic enophthalmos.

Adult↗
PubMed1996

Structural and neurobehavioral delay in postnatal brain development of preterm infants.

Postnatal brain development of healthy prematurely born infants was assessed to study possible influence of premature birth and early extrauterine environment on structural, biochemical, and functional brain development. Myelination and differentiation of gray and white matter were studied by in vivo magnetic resonance (MR) imaging (MRI), changes in cerebral metabolism by 1HMR spectroscopy (MRS), and changes in early human neurobehavior by the assessment of preterm infant's behavior (APIB). The stage of intrauterine and extrauterine brain development in prematurely born infants at term was compared with the stage of mainly intrauterine brain development in a group of full-term infants. Eighteen preterm infants unremarkable with respect to neurologic and medical status were studied at approximately 2 wk of postnatal age [gestational age (GA) 1: 32.5 +/- 1.2 wk] and again at term (GA 2: 40.0 +/- 1.1 wk). For comparison a group of 13 full-term born infants (GA T: 40.6 +/- 2.1 wk) were studied by MR and six by APIB. When GA 2 to GA 1 was compared, significant maturational changes were found with MRI in gray and white matter and myelination, with 1H MRS in the concentration of N-acetylaspartate and with all scores of APIB. In preterm infants at term (GA 2) compared with full-term infants (GA T) significantly less gray and white matter differentiation and myelination was observed as well as significantly poorer performance in four neurobehavioral parameters (autonomic reactivity, motoric reactivity, state organization, attentional availability). We conclude that MRI and 1H MRS can be used to study postnatal brain development in preterm infants. Structural and biochemical maturation is accompanied by functional maturation as shown with the neurobehavior assessment. Preterm infants at term compared with full-term infants show a structural as well as a functional delay in brain development assessed at 40 wk of postconceptional age.

Age Factors↗
PubMed1995

[Quiz on an unusual orbital masquerade syndrome].

BACKGROUND: After consulting the here presented CT-images of the orbit, the question was raised whether the ocular bulbus was really enucleated or the anamnesis was wrong and a lymphoma existed in the orbit. We will therefore discuss a case of a special follow-up after an enucleation with implantation of a "Bangerter Plomb". CASE REPORT: In 1988 the patient, born on February 1, 1947, underwent an enucleation of the right eye with implantation of a "Bangerter Plomb" because of posttraumatic phthisis dolorosa. The postoperative follow up was complicated by a reactive psychopathological development with automutilation. In 1992, a Non-Hodgkin lymphoma of the mandibula was detected and treated. During the year of 1994, a painful swelling of the right orbit developed. The orbital CT suggested a recurrence of the lymphoma in the right eye, which seemed to be still in place. The biopsy however showed an abscess cavity and some parts of the Bangerter implant. CONCLUSIONS: The abscess cavity with the connected muscles and the interruption of the optic nerve which was only partially visible simulated the presence of a bulbus; the rest of the implant, on the other hand, simulated the presence of a lymphoma. The two main reasons for the infection were an early dehiscence of the wound and the automutilation. This "syndrome of masquerade" could have been detected earlier if the ophthalmologists and the neuroradiologists would have discussed the CT-images together earlier.

Abscess↗
PubMed1994

Value of three-dimensional computed tomography in craniomaxillofacial surgery.

Three-dimensional (3-D) computed tomographic (CT) scans of 72 adult patients were evaluated by two observers in a blinded fashion by comparing the 3-D images with the two-dimensional (axial and coronal) CT scans. With 3-D CT, the observers found improved visualization of facial anatomy in certain patients (i.e., asymmetries of the whole face and skull, large defects of the midface and skull vault, and fractures with major dislocation). In these defects, the information can be assimilated more rapidly. The documentation of effects of cranial surgery on craniofacial growth and resorption after reconstruction with autologous material can also be evaluated more accurately. Because higher levels of radiation are used, 3-D CT protocols are less indicated in patients with minor dislocation of fractures, tumors, and inflammations. Three-dimensional CT images in these patients are of little help and can mislead the surgeon. Further improvements in hardware and software will allow more accurate surgical planning by performing interactive surgery or by producing precise models.

Adolescent↗
PubMed1994

[Orbital volumetry as a planning principle for reconstruction of the orbital wall].

Before reconstruction of the orbital walls and other surgical procedures concerning the orbits leading to a modification of pathologically altered orbital volumes, it is useful to measure these volumes in order to allow preciser correction. Orbital volumetric studies on 22 patients and 6 dry skulls were performed using high resolution computer tomography. 14 patients presented enophthalmos of various origin, 3 patients fibrous dysplasia involving the orbits and 5 patients showed no orbital pathology. In 10 patients with unilateral posttraumatic enophthalmos an increase of the bony orbital volume of 20.1% in the average was found corresponding to an enophthalmos of 3.5 mm in the average. Correlation between the severity of the enophthalmos and the increase in orbital volume was found. Enophthalmos could not be correlated to the intraorbital fat volume, especially no atrophy of orbital fat could be demonstrated in these patients. Normal orbital volume measurements of patients and dry skulls were compared to those found in the literature. Planning of the surgery was therefore facilitated before correction of enophthalmos, reconstruction of bony orbital contour after tumor resection and in patients with fibrous dysplasia. Results suggest that the bony orbital enlargement, followed by a change in soft-tissue shape and position is the usual cause for posttraumatic enophthalmos. Changes in volume of soft-tissues themselves are less significant.

Cephalometry↗
PubMed1993

Compound heterozygosity for metachromatic leukodystrophy and arylsulfatase A pseudodeficiency alleles is not associated with progressive neurological disease.

Several allelic mutations at the arylsulfatase A (ASA) locus cause substantial deficiencies of this lysosomal enzyme. Depending on the genetically determined degree of the deficiency, the clinical outcome may be very different--either metachromatic leukodystrophy (MLD), a lethal lysosomal storage disorder affecting the nervous system, or, more frequently, the so-called pseudodeficiency (PD), which has no apparent clinical consequence. Because of compound heterozygosity for MLD and PD, 1/1,000 individuals in the population have low residual enzyme activities, which are intermediate between those of MLD patients and those of PD homozygous normal individuals. In order to assess whether PD/MLD compound heterozygotes bear a health risk, we examined clinically and biochemically 16 individuals with this genotype. Of these subjects, two had neurological symptoms and two showed lesions, without clinical symptoms, in magnetic resonance imaging of the brain. None of these symptoms was progressive, nor did they resemble those of MLD. Nerve conduction velocities were normal in these probands, and they secreted only low amounts of sulfatide in the urine. We conclude that the observed neurological symptoms are unrelated to the ASA genotype and that PD/MLD compound heterozygotes are not at an increased risk for developing progressive nervous system diseases.

Adolescent↗
PubMed1993

[Magnetic resonance imaging in neuroradiology. Indications and applications].

On the basis of own experience with 250 MR-Angiographies and with reference to the literature the authors report on the role MR-Angiography is assuming in neuroradiological diagnostic procedures. As a noninvasive method MR-Angiography contributes to the evaluation of vessel stenosis and occlusion, venous sinus thrombosis and neurovascular compression syndromes. It supports the work-up of space-occupying lesions, as well as arteriovenous malformations and aneurysms. In addition to the diagnosis, follow-up examinations serve as a noninvasive means of therapy control particularly after interventional endovascular procedures. Knowledge of the diagnostic capabilities and limitations, the choice of the correct examination technique and modification of technical variables contribute to establish MR-Angiography as a valuable adjunct to MR imaging.

Aneurysm↗
PubMed1992

Spinal leptomeningeal neoplastic disease. Evaluation by MR, myelography and CT myelography.

Out of 16 patients, spinal leptomeningeal neoplastic disease was diagnosed by MRI in 4 patients, myelography in 14 patients and CT myelography in 12 cases. MR was superior to myelography in 2 patients, in another 2 patients MRI was equally diagnostic. The cerebrospinal fluid of every patient contained malignant cells. Histological evidence for primary central nervous system tumors was found in 5 cases. In 10 cases, non-neuraxial malignancy consisted of small cell carcinoma of the lung (7 cases), and leukemia and lymphoma (3 patients). In 1 patient, primary leptomeningeal malignant melanoma was confirmed at autopsy. Preferential thoracolumbar neoplastic morphologic manifestation correlated with the presence of conus and cauda equina syndrome in 9 patients, low back pain, paresthesia and spinal root signs in 7 patients. False-negative interpretation of myelography in 2 patients with positive MR findings, and the impressive sensitivity of gadolinium Dota to improve visualization of subarachnoid spread, favor MRI as an alternative imaging technique in the assessment of patients with suspected intradural extramedullary malignancy.

Adult↗
PubMed1991

Acute and chronic neuroborreliosis with and without CNS involvement: a clinical, MRI, and HLA study of 27 cases.

Of the 96 serologically confirmed neuroborreliosis cases seen in our clinic between 1983 and 1988, 11 patients had mild to moderate and 4 patients had serious cerebral and/or spinal cord symptoms. Nine of these 15 patients with CNS involvement exhibited a primary chronic course of the illness. After high-dose intravenous therapy with penicillin, doxycycline or cefotaxime, given mostly in combination with cortisone, gradual recovery occurred with normalization of CSF findings characteristic of neuroborreliosis, and normalization of significantly elevated Borrelia burgdorferi IgG antibody titres in CSF and serum. Brain MRI and CT showed evidence of or were suggestive of vascular involvement which correlated with clinical symptoms in 11 of the 15 patients with CNS involvement. Brain MRI changes that were similar but much slighter in number and intensity were seen in 5 of 12 neuroborreliosis patients without clinical signs of CNS involvement (lymphocytic meningoradiculitis; Bannwarth's syndrome). The frequencies of the HLA-DR7 (75%), HLA-B44 (50%) and HLA-A29 (33%) antigens in 12 neuroborreliosis patients with clinical symptoms of CNS involvement were significantly different from the frequencies in 12 neuroborreliosis patients without CNS involvement and in 100 control subjects. Diagnostic criteria of active neuroborreliosis are proposed.

Acute Disease↗
PubMed1990

[Magnetic resonance in oncology].

The physical and biological background to magnetic resonance imaging (MRI) in patients with neoplasms is reviewed. The clinical indications for this method of diagnosis, staging, and follow-up of malignant neoplasms are discussed on the basis of the guidelines given by the MRI Consensus Conference on April 25-26, 1989, in Berne. MRI is the modality of choice in patients with neoplasms of the central nervous system and the musculoskeletal system. Further emerging indications for MRI are neoplasma of the ENT region, liver, and pelvic organs. Finally, the foreseeable developments in MRI and in magnetic resonance spectroscopy (MRS) are mentioned.

Abdominal Neoplasms↗
PubMed1990

The "dense artery sign"--major cerebral artery thromboembolism demonstrated by computed tomography.

A 4 years review of high resolution thin slice (3-5 mm) computed tomography performed within 24 h after cerebral infarction revealed increased density in a major cerebral artery segment in 28 patients. Arteries affected were the vertebral and basilar artery in 6 and 8 patients, the sphenoid course of the middle cerebral artery in 13 cases and the extracranial internal carotid artery in 1 patient. In 35.7% of cases the so called "dense artery sign" provided earliest evidence of the ensuing infarction documented by CT controls in most patients. Angiography carried out in 8 patients, density calculations in the course of the affected vessel and resolution of the increased density on subsequent CT examinations suggest thrombembolism as the most likely etiology. In the clinical setting of acute stroke increased artery density encompassing the entire vessel diameter may serve as an early indicator of major cerebral artery occlusion and prompt angiographic investigation of a lesion potentially amenable to lysis.

Adult↗
PubMed1990

[Malignant melanoma of the meninges--MR and CT diagnosis].

Malignant melanoma of the meninges is a rare neoplasm derived from melanocytes of the cranial or spinal meninges. Histologically classified as grade IV tumours, malignant melanoma may present either as a diffuse meningeal neoplasm, first described by Virchow in 1859, or as a circumscribed tumour attached to the meninges. Although diagnosis is rarely established prior to surgery or autopsy, MR and CT may provide indispensable information probably leading to earlier diagnosis. In 4 patients, diagnosis of a primary meningeal melanoma was based on MR and CT findings and histology. Histology was obtained in 3 cases by surgery, in one patient by autopsy and showed a melanotic and an amelanotic malignant melanoma in 2 patients each. Autopsy was carried out in 3 cases after survival of 4, 5, and 18 months; in a single case, the follow-up period is almost 3 years.

Adolescent↗