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G Schroth

Publications and source records attributed to G Schroth.

At least 109 records · Page 6Linked to original sources
PubMed1997

Retardation of myelination due to dietary vitamin B12 deficiency: cranial MRI findings.

Vitamin B12 deficiency is known to be associated with signs of demyelination, usually in the spinal cord. Lack of vitamin B12 in the maternal diet during pregnancy has been shown to cause severe retardation of myelination in the nervous system. We report the case of a 14(1)/2-month-old child of strictly vegetarian parents who presented with severe psychomotor retardation. This severely hypotonic child had anemia due to insufficient maternal intake of vitamin B12 with associated megaloblastic anemia. MRI of the brain revealed severe brain atrophy with signs of retarded myelination, the frontal and temporal lobes being most severely affected. It was concluded that this myelination retardation was due to insufficient intake of vitamin B12 and vitamin B12 therapy was instituted. The patient responded well with improvement of clinical and imaging abnormalities. We stress the importance of MRI in the diagnosis and follow-up of patients with suspected diseases of myelination.

Anemia, Megaloblastic↗
PubMed1997

Perinatal ultrasonography and magnetic resonance imaging findings in congenital hydrocephalus associated with fetal intraventricular hemorrhage.

OBJECTIVE: We present the case histories of three premature infants with congenital posthemorrhagic hydrocephalus. STUDY DESIGN: The timing of the lesion was monitored in utero in two of the three cases. Magnetic resonance imaging studies (prenatal in one case, within 24 hours of birth in all three cases) established the duration of the lesions and thereby added to the ultrasonographic findings. RESULTS: All three patients demonstrated a similar pattern of lesions, consisting of (1) unilateral germinal matrix hemorrhage with cystic resorption, (2) residual blood in the cerebrospinal fluid with a "granular" ependymal reaction, (3) asymmetric ventriculomegaly predominating on the side of the hemorrhage with mild atrophy and periventricular cysts, and (4) partial hypoplasia of the ipsilateral thalamus. On the basis of two cases in which information about the pregnancy was available and in which fetal oligohydramnios without ruptured membranes was detected, we assume that this pattern of lesions may have resulted from a hypoxic-ischemic episode followed by intraventricular hemorrhage. CONCLUSIONS: Because these three infants with congenital hydrocephalus were born during a period of only 18 months in a perinatal center serving a region with 16,000 live births per year, we speculate that a posthemorrhagic cause for congenital hydrocephalus underestimated.

Adult↗
PubMed1997

Infrapopliteal transcatheter interventions for limb salvage in diabetic patients: importance of aggressive interventional approach and role of transcutaneous oximetry.

OBJECTIVES: This study sought to determine whether infrapopliteal transcatheter interventions can salvage ischemic limbs in diabetic patients referred for below the knee amputation at our institution. BACKGROUND: The value of transcatheter interventions in diabetic crural arteries is controversial. Tissue oxygen partial pressure (TCO2) levels < 40 mm Hg predict poor wound healing. METHODS: Percutaneous interventions were performed in 29 consecutive diabetic patients in need of limb salvage. Technical success was defined as < 20% residual vessel stenosis. Clinical success was defined as the avoidance of amputation and achievement of wound healing. At hospital discharge, patients were treated with Coumadin and aspirin. Ankle-brachial index (ABI) and TCO2 measurements were obtained before and after the intervention. RESULTS: After 12-month follow-up, six patients had presistent wounds, whereas 23 experienced wound healing. Forty of the 50 infrapopliteal arteries successfully dilated were occluded, with a mean (+/-SD) lesion length of 18.0 +/- 3.5 cm. After the procedure, TCO2 improved from 27.82 +/- 9.97 mm Hg (95% confidence interval [CI] 23.95 to 31.69) to 54.5 +/- 14.73 mm Hg (95% CI 48.79 to 60.21, p < 0.0001), whereas the ABI did not (p > 0.2). TCO2 predicted procedural and clinical success (p < 0.0182). CONCLUSIONS: Infrapopliteal transcatheter interventions in diabetic patients may salvage the majority of limbs doomed to amputation. Although TCO2 measurements are valuable in predicting wound healing and success after interventions, ABI measurements are not.

Angiography↗
PubMed1997

[Special technics for angioplasty of the brachiocephalic vessels].

PURPOSE: Description of special techniques for retrograde angioplasty of cerebral arteries with protection of the brain. MATERIAL AND METHOD: During the last 3 years, 51 dilatations of cerebral vessels were carried out in 45 patients; in 8, special techniques were required. In cases with particular operative risks, angioplasty of cerebral vessels can be performed using various techniques (double catheter [8 cases], retrograde PTA [8 cases], kissing balloon technique [3 cases]). RESULTS: All stenoses were successfully dilated, using a local anaesthetic. One patient with a double stenosis of the common carotid artery developed severe headache and visual disturbances in the ipsilateral eye following dilatation of a tight stenosis with total remission of all symptoms within 24 hours. CONCLUSION: Stenoses of cerebral arteries where surgery would be difficult and associated with a high risk can be dilated by retrograde PTA using a double catheter technique with a low complication rate.

Aged↗
PubMed1997

Nontraumatic spinal epidural hematomas. MR features.

PURPOSE: Spinal epidural hematoma (SEH) is a rare clinical entity with a bleak outcome. The aim of our study was to establish the value of MR findings in the diagnosis of nontraumatic SEH. MATERIAL AND METHODS: Seven patients with nontraumatic SEH were examined by MR at 1.5 T. Two patients were under anticoagulation therapy with heparin, and 2 others were taking salicylic acid. One patient had lupus erythematodes with a marked thrombocytopenia. One patient had a spinal arteriovenous malformation. RESULTS: MR imaging permitted the accurate localization of extradural intraspinal expansive lesions which exhibited the characteristic signal intensities of blood. Five patients underwent laminectomy and evacuation of the hematoma. In the acute phase, the hematomas appeared isointense when compared with the spinal cord on T1-weighted images and hyperintense on T2-weighted images. Later the hematomas were hyperintense on T1-weighted images and showed signals identical to those of cerebrospinal fluid (CSF) on T2-weighted images. CONCLUSION: MR imaging established the exact diagnosis and localization of SEH in all cases. MR also can provide useful information about the age of the hematomas.

Acute Disease↗
PubMed1997

Human cortical plasticity: functional recovery with mirror movements.

Cortical plasticity of the human brain permits functional recovery after brain injury even in the absence of neuronal recovery. We report the combined evaluation, including electrophysiology and functional magnetic resonance imaging, of the pattern of cortical and cerebellar reorganization, in a patient with mirror movements as a sequel of perinatal unilateral brain injury. Recovery resulted in motor control by the healthy hemisphere using direct ipsilateral corticospinal projections and the contralateral cerebellum.

Adolescent↗
PubMed1997

Transcranial color-coded duplex sonography in the evaluation of collateral flow through the circle of Willis.

PURPOSE: To determine the sensitivity, specificity, and positive and negative predictive values of transcranial color-coded duplex sonographic (TCCD) evaluation of cross flow through the anterior (ACoA) and posterior (PCoA) communicating arteries in patients with occlusive cerebrovascular disease. METHODS: We studied prospectively 132 patients (37 women, 95 men; mean age, 60 years) with stenoses of more than 69% reduction in vessel diameter (n = 93) and occlusions (n = 52) of the internal carotid artery, and three occlusions of the basilar artery. The sonographer was aware of extracranial sonographic findings but was blinded to the results of cerebral angiography. RESULTS: Nine patients (7%) with thick bones preventing transtemporal insonation and three patients (3%) with occlusions of the middle (n = 3) and anterior (n = 1) cerebral arteries were excluded. Sensitivity of TCCD for detection of collateral flow through the ACoA in patients with occlusive carotid artery disease was 98%, specificity was 100%, positive predictive value was 100%, and negative predictive value was 98%. The corresponding values for the PCoA were 84%, 94%, 94%, and 84%, respectively. All three functional PCoAs were identified in patients with occluded basilar arteries. CONCLUSION: TCCD is a valuable method for noninvasive evaluation of cross flow through the ACoA in patients with adequate sonographic windows. However, TCCD evaluation of cross flow through the PCoA is less reliable, because hemodynamic criteria may cause falsely positive and falsely negative results.

Adult↗
PubMed1997

Arteriovenous shunt measurement during endovascular therapy for cerebrospinal lesions.

PURPOSE: To determine (a) whether superselective angioscintigraphy with technetium-99m macroaggregated albumin (99mTc-MAA) can be used for the evaluation of arteriovenous shunting in tumors and vascular malformations of the head and spine and (b) whether the amount of microparticles shunted is related to diagnosis, lesion size, or angiographic pattern. METHODS: Particles of 99mTc-MAA with a calibrated diameter of 25 to 50 microm were delivered intraarterially in feeders of head and spine tumors and vascular malformations in 38 patients. The first estimation of the proportion of particles reaching the lungs was made on-line in the angiography suite using a hand-held lead-shielded detector. Evaluation of the intralesional shunt (pulmonary shunt index, or PSI) was derived from quantitative gamma camera recordings of tumoral and pulmonary activity after the embolization procedure was complete. RESULTS: The PSI value ranged from 48% to 100% for vascular malformations and vascular tumors (n = 11), 82% to 95% for juvenile angiofibromas (n = 4), 63% to 70% for high-grade gliomas (n = 2), 0% to 50% for renal cell carcinoma metastases (n = 4), 0% to 86% for meningiomas (n = 11), and 0% to 36% for paragangliomas (n = 6). Angiographically, the presence of visible arteriovenous channels was predictive of a high PSI. In contrast, the presence of early venous drainage was associated with a wide PSI range. CONCLUSION: Superselective 99mTc-MAA angioscintigraphy of tumors and vascular malformations of the head and spine is a valuable method for quantifying an intralesional arteriovenous shunt before embolization.

Adolescent↗
PubMed1996

[Spinal stenosis: current aspects of imaging diagnosis and therapy].

Lumbar spinal stenosis typically manifests itself through low back pain and neurogenic claudication during walking. Cervical spinal stenosis may manifest itself through a multitude of symptoms. Spinal stenosis is classified into congenital or primary and acquired or secondary forms. Conventional X-rays of the spine often reveal only unspecific findings. Computed tomography (CT) is the preferred method of judging the width and anatomy of the spinal canal. Myelography remains a good method of imaging the spinal cord in its entirety and in addition allows functional imaging of the width of the spinal canal with functional stress images. CT performed directly after myelography (myelo-CT) allows specific imaging of areas still unclear. Magnetic resonance imaging (MRI) allows multiplanar imaging of the spine and better soft tissue definition. Surgical therapy is discussed in relation to the clinical and neuroradiological findings.

Aged↗
PubMed1996

Preoperative embolization of paragangliomas and angiofibromas. Measurement of intratumoral arteriovenous shunts.

OBJECTIVE: To determine if technetium Tc 99m-labeled macroaggregated albumin selective angioscintigraphy enables estimation of microparticle-arteriovenous shunt in branchial paragangliomas and nasopharyngeal angiofibromas. DESIGN: Technetium Tc 99m-labeled macroaggregated albumin particles with calibrated diameters between 25 and 50 microns were administered during selective catheterization of the feeding arteries in 4 branchial paragangliomas (glomus tumors) and 4 nasopharyngeal angiofibromas. Preliminary measures of the activity of the tumor region and of the lungs were obtained in the angiography suite using a hand-held detector. Without changing the position of the microcatheter, definitive embolization was performed. After endovascular treatment, scintigraphy was performed and the pulmonary shunt index was calculated with the use of a gamma camera and a dedicated computer program. RESULTS: The pulmonary shunt index varied between 0% and 36% for branchial paragangliomas (glomus tumors) and between 82% and 95% for angiofibromas. CONCLUSIONS: Our results provide new evidence that the incidence of microparticle-arteriovenous shunt in nasopharyngeal angiofibromas is much higher than in paragangliomas.

Adolescent↗
PubMed1996

Recordings of eye movements for stimulus control during fMRI by means of electro-oculographic methods.

A method for monitoring eye movements in humans during functional MRI is presented. It is based on the acquisition of electro-oculographic (EOG) signals near one eye. EOG potentials were amplified and converted into an optical signal just outside the head coil. An optical fiber was used for signal transmission from inside the magnet bore to the control room. The EOG sensor was tested during EPI sequences at 1.5 Tesla without contamination of the MR signal. Some flow related artifacts on the EOG were observed inside the magnet, but no additional interactions from the MR sequence. An analysis of the latency, direction, and amplitude of the saccadic eye movements was possible.

Electrooculography↗
PubMed1996

Diagnostic criteria for transcranial colour-coded duplex sonography evaluation of cross-flow through the circle of Willis in unilateral obstructive carotid artery disease.

A transcranial colour-coded duplex sonography (TCCD) study was performed to establish reliable criteria for the assessment of collateral flow through the anterior (ACoA) and posterior (PCoA) communicating artery without using compression tests. We studied 86 patients with angiographically evaluated unilateral > 69% stenosis (n = 53) and occlusion (n = 33) of the carotid artery. The following TCCD criteria were evaluated: for diagnosis of cross-flow through the ACoA, detection of reversed flow in the anterior cerebral artery (ACA) on the obstructed (ipsilateral) side. For the diagnosis of cross-flow through the PCoA: (A) identification of the PCoA; (B) peak systolic velocity in P1 posterior cerebral artery (PCA) higher than the mean value + 2 SD of normals; (C) ratio of ipsilateral peak systolic P1 PCA velocity to peak systolic P1 PCA velocity to peak systolic P2 PCA velocity higher than the mean ratio + 2 SD of normals; (D) ratio of ipsilateral peak systolic P1 PCA velocity to contralateral peak systolic P1 PCA velocity higher than the mean ratio + 2 SD of normals; (E) peak systolic basilar artery velocity higher than the mean value + 2 SD of normals. Eight patients (9%) with inadequate temporal ultrasonic windows were excluded. The sensitivity and specificity for TCCD evaluation of ACoA cross-flow were 100%. Using criteria A and B the corresponding values for the PCoA were 85 and 98%, respectively. Criteria C-E were not useful owing to lower sensitivity. In conclusion, we delineated TCCD criteria that make it possible to assess reliably the cross-flow through the circle of Willis in patients with adequate ultrasonic windows.

Adult↗
PubMed1996

Transcranial colour-coded duplex sonography of cerebral arteriovenous malformations.

A transcranial colour-coded duplex sonography (TCCD) study was performed to evaluate the sensitivity of detection and the feasibility of visualising details of cerebral arteriovenous malformations (AVMs). We prospectively examined 15 patients with 2 large (> 4 cm), 7 medium-size (2-4 cm) and 6 small (< 2 cm) radiologically proven supratentorial AVMs of the brain using TCCD. A feeding vessel was diagnosed if the velocities and/or the relative interhemisphere velocity difference between feeding and non-feeding anterior, middle and posterior cerebral arteries were more than two standard deviations above the means of 136 age- and sex-matched normals. The sonographer was blinded to the results of cerebral angiography. Using TCCD it was possible to detect all large and medium-size lesions, and 4 of 6 small ones, because 23 of 29 (79%) feeding arteries showed abnormal haemodynamics. In addition, 8 of 46 (17%) feeding branches of cerebral arteries were shown. However, all but 2 large draining veins and sinus were not detected. In view of the availability of MRI, MRA and angiography, TCCD is not the method of choice in screening for cerebral AVMs. However, careful assessment of the velocities in the intracranial arteries permits incidental detection of cerebral AVMs and characterisation of the haemodynamics in the feeding arteries.

Adult↗
PubMed1996

Comparison of angioscopy, intravascular ultrasound imaging and quantitative coronary angiography in predicting clinical outcome after coronary intervention in high risk patients.

OBJECTIVES: The purpose of this study was to identify qualitative or quantitative variables present on angioscopy, intravascular ultrasound imaging or quantitative coronary arteriography that were associated with adverse clinical outcome after coronary intervention in high risk patients. BACKGROUND: Patients with acute coronary syndromes and complex lesion morphology on angiography are at increased risk for acute complications after coronary angioplasty. Newer devices that primarily remove atheroma have not improved outcome over that of balloon angioplasty. Intravascular imaging can accurately identify intraluminal and intramural histopathologic features not adequately visualized during coronary arteriography and may provide mechanistic insight into the pathogenesis of abrupt closure and restenosis. METHODS: Sixty high risk patients with unstable coronary syndromes and complex lesions on angiography underwent angioscopy (n = 40) and intravascular ultrasound imaging (n = 46) during interventional procedures. In 26 patients, both angioscopy and intravascular ultrasound were performed in the same lesion. All patients underwent off-line quantitative coronary arteriography. Coronary interventions included balloon (n = 21) and excimer laser (n = 4) angioplasty, directional (n = 19) and rotational (n = 6) atherectomy and stent implantation (n = 11). Patients were followed up for 1 year for objective evidence for recurrent ischemia. RESULTS: Patients whose clinical presentation included rest angina or acute myocardial infarction or who received thrombolytic therapy within 24 h of procedure were significantly more likely to experience recurrent ischemia after intervention. Plaque rupture or thrombus on preprocedure angioscopy or angioscopic thrombus after intervention were also significantly associated with adverse outcome. Qualitative or quantitative variables on angiography, intravascular ultrasound or off-line quantitative arteriography were not associated with recurrent ischemia on univariate analysis. Multivariate predictors of recurrent ischemia were plaque rupture on preprocedure angioscopy (p < 0.05, odds ratio [OR] 10.15) and angioscopic thrombus after intervention (p < 0.05, OR 7.26). CONCLUSIONS: Angioscopic plaque rupture and thrombus were independently associated with adverse outcome in patients with complex lesions after interventional procedures. These features were not identified by either angiography or intravascular ultrasound.

Angioplasty, Balloon, Coronary↗
PubMed1996

Memory without context: amnesia with confabulations after infarction of the right capsular genu.

OBJECTIVE: To explore the mechanism of an amnesia marked by confabulations and lack of insight in a patient with an infarct of the right inferior capsular genu. The confabulations could mostly be traced back to earlier events, indicating that the memory disorder ensued from an inability to store the temporal and spatial context of information acquisition rather than a failure to store new information. METHODS: To test the patient's ability to store the context of information acquisition, two experiments were composed in which she was asked to decide when or where she had learned the words from two word lists presented at different points in time or in different rooms. To test her ability to store new information, two continuous recognition tests with novel non-words and nonsense designs were used. Recognition of these stimuli was assumed to be independent of the context of acquisition because the patient could not have an a priori sense of familiarity with them. RESULTS: The patient performed at chance in the experiments probing knowledge of the context of information acquisition, although she recognised the presented words almost as well as the controls. By contrast, her performance was normal in the recognition tests with non-words and nonsense designs. CONCLUSION: These findings indicate that the patient's amnesia was based on an inability to store the context of information acquisition rather than the information itself. Based on an analysis of her lesion, which disconnected the thalamus from the orbitofrontal cortex and the amygdala, and considering the similarities between her disorder, Wernicke-Korsakoff syndrome, and the amnesia after orbitofrontal lesions, it is proposed that contextual amnesia results from interruption of the loop connecting the amygdala, the dorsomedial nucleus, and the orbitofrontal cortex.

Amnesia↗
PubMed1996

Internal carotid artery dissection: MR imaging features and clinical-radiologic correlation.

PURPOSE: To analyze the usefulness of magnetic resonance (MR) imaging techniques and diagnostic sensitivity in internal and carotid artery dissection (ICAD) and to correlate these findings with those of other imaging modalities and with clinical signs. MATERIALS AND METHODS: Thirty-one patients with ICAD underwent MR imaging within 2-40 days (mean, 13 days) after onset of clinical symptoms. All patients initially underwent Doppler sonography; 15 patients underwent additional angiographic studies. RESULTS: T1-weighted fat-suppressed MR images most accurately demonstrated intramural hematoma in the internal carotid artery (ICA) in all patients. Kinking or coiling of the ICA was found in nine (29%) patients. Hyperintense signal was seen on T1- and T2-weighted images in the carotid canal or in the cavernous sinus in two-thirds of the patients. Findings characteristic of ICAD were seen on 13 of 16 angiograms. CONCLUSION: MR imaging most accurately demonstrated ICAD. The high rate of kinking and coiling in the carotid artery suggests that these anatomic conditions may be predisposing factors.

Adult↗
PubMed1996

Transcranial color-coded duplex sonography in unilateral flow-restrictive extracranial carotid artery disease.

PURPOSE: To provide transcranial color-coded duplex flow-velocity data for the basal cerebral arteries in patients with unilateral flow-restrictive extracranial carotid artery disease, and to compare these data with the flow velocities obtained in healthy control subjects. METHODS: Transcranial color-coded duplex sonography was performed in 78 patients with different patterns of cross flow through the anterior and posterior communicating arteries associated with unilateral obstruction (70% to 100%; 46 stenoses and 32 occlusions) of the internal carotid arteries. Peak systolic, mean, and end diastolic velocities were measured in the anterior, middle, and precommunicating and postcommunicating posterior cerebral arteries. These measurements were compared with the values obtained in 125 age- and sex-matched health control subjects. RESULTS: Patients with anterior communicating artery cross flow to the middle cerebral artery (63%) had increased peak velocity in the anterior cerebral artery and decrease peak velocity in the middle cerebral artery on the obstructed (ipsilateral) side, and increased peak velocity in the anterior cerebral artery on unobstructed (contralateral) side. Patients with anterior communicating artery cross flow to the pericallosal artery (19%) had increased contralateral peak systolic velocity and mean anterior cerebral artery velocities. Patients without anterior communicating artery cross flow (18%) had normal peak velocities in the anterior and middle cerebral arteries. Patients with posterior communicating artery cross flow (42%) had ipsilaterally decreased peak systolic and mean middle cerebral artery velocities and increased peak velocities in the precommunicating posterior cerebral artery. Patients without posterior communicating artery cross flow (58%) had ipsilaterally decreased peak systolic and mean middle cerebral artery velocities. CONCLUSION: Our findings suggest that typical abnormalities of basal cerebral artery flow velocities occur in patients with unilateral 70% to 100% obstruction of the internal carotid arteries resulting in different patterns of cross flow through the circle of Willis.

Adult↗