[Hemiballism-hemichorea syndrome].
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Anti-Dyskinesia Agents↗
Biomedical subjects
F Ebner
Publications and source records attributed to F Ebner.
Review of source images is necessary for the evaluation of gadolinium-enhanced MR angiography for renal artery stenosis.
The purpose of this study was to assess interobserver variability and accuracy in the evaluation of renal artery stenosis (RAS) with gadolinium-enhanced MR angiography (MRA) and digital subtraction angiography (DSA) in patients with hypertension. The authors found that source images are more accurate than maximum intensity projection (MIP) for depicting renal artery stenosis. Two independent radiologists reviewed MRA and DSA from 38 patients with hypertension. Studies were post-processed to display images in MIP and source images. DSA was the standard for comparison in each patient. For each main renal artery, percentage stenosis was estimated for any stenosis detected by the two radiologists. To calculate sensitivity, specificity and accuracy, MRA studies and stenoses were categorized as normal, mild (1-39%), moderate (40-69%) or severe (> or =70%), or occluded. DSA stenosis estimates of 70% or greater were considered hemodynamically significant. Analysis of variance demonstrated that MIP estimates of stenosis were greater than source image estimates for both readers. Differences in estimates for MIP versus DSA reached significance in one reader. The interobserver variance for MIP, source images and DSA was excellent (0.80< kappa< or = 0.90). The specificity of source images was high (97%) but less for MIP (87%); average accuracy was 92% for MIP and 98% for source images. In this study, source images are significantly more accurate than MIP images in one reader with a similar trend was observed in the second reader. The interobserver variability was excellent. When renal artery stenosis is a consideration, high accuracy can only be obtained when source images are examined.
Adolescent↗
Acupuncture using laser needles modulates brain function: first evidence from functional transcranial Doppler sonography and functional magnetic resonance imaging.
Acupuncture using laser needles is a new totally painless stimulation method which has been described for the first time. This paper presents an experimental double-blind study in acupuncture research in healthy volunteers using a new optical stimulation method. We investigated 18 healthy volunteers (mean age +/- SD: 25.4 +/- 4.3 years; range: 21-30 years; 11 female, 7 male) in a randomized controlled cross-over trial using functional multidirectional transcranial ultrasound Doppler sonography (fTCD; n = 17) and performed functional magnetic resonance imaging (fMRI) in one volunteer. Stimulation of vision-related acupoints resulted in an increase of mean blood flow velocity in the posterior cerebral artery measured by fTCD [before stimulation (mean +/- SE): 42.2 +/- 2.5; during stimulation: 44.2 +/- 2.6; after stimulation: 42.3 +/- 2.4 cm/s, n.s.]. Mean blood flow velocity in the middle cerebral artery decreased insignificantly. Significant changes (p < 0.05) of brain activity were demonstrated in the occipital and frontal gyrus by fMRI. Optical stimulation using properly adjusted laser needles has the advantage that the stimulation cannot be felt by the patient (painless and no tactile stimulation) and the operator may also be unaware of whether the stimulation system is active. Therefore true double-blind studies in acupuncture research can be performed.
Acupuncture↗
Serum total 8-iso-prostaglandin F2alpha: a new and independent predictor of peripheral arterial disease.
OBJECTIVE: Circulating 8-iso-prostaglandin F 2alpha (8-iso-PGF 2alpha ) has been proposed as new indicator of oxidative stress, which is involved in the pathophysiologic changes of atherosclerosis. We proposed to test the hypothesis that 8-iso-PGF 2alpha is an independent predictor of symptomatic peripheral arterial disease (PAD). METHODS: A case-control study in 100 patients with symptomatic PAD and 100 control subjects matched for age, sex, and diabetes mellitus was conducted. Smokers and subjects using lipid-lowering drugs were excluded. Serum total 8-iso-PGF 2alpha was quantified with an enzyme immunoassay. RESULTS: Median 8-iso-PGF 2alpha was higher in patients with PAD than in control subjects (63 vs 42 pg/mL; P = .001). Logistic regression with hypertension, body mass index, and creatinine, low-density lipoprotein (LDL) cholesterol, triglyceride, high-sensitivity C-reactive protein (hs-CRP), 8-iso-PGF 2alpha , and total homocysteine concentrations as independent variables and case-control status as dependent variable revealed significant odds ratios (OR) for hypertension (OR, 3.74; 95% confidence interval [CI], 1.85-7.53), low-density lipoprotein cholesterol (OR, 1.16, for an increment of 10 mg/dL; 95% CI, 1.07-1.27), high-sensitivity C-reactive protein (OR, 1.02, for an increment of 1 mg/L; 95% CI, 1.00-1.03), and 8-iso-PGF 2alpha (OR, 1.11, for an increment of 10 pg/mL; 95% CI, 1.03-1.20). CONCLUSIONS: Serum total 8-iso-PGF 2alpha was an independent predictor of PAD in the population studied. This finding supports the hypothesis that 8-iso-PGF 2alpha is a risk marker for PAD. Our results indicate increased systemic oxidative stress in patients with PAD.
Aged↗
Degree of hypomyelination and magnetic resonance spectroscopy findings in patients with Pelizaeus Merzbacher phenotype.
As only 10 - 30 % of patients with a Pelizaeus Merzbacher disease (PMD) phenotype carry mutations of the proteolipid protein (PLP) gene, we were interested if the degree and time-dependent progression of abnormal MRI and MRS findings would discriminate patients with mutations of the PLP gene (Pelizaeus Merzbacher disease, PMD) from patients without a defect of the PLP gene (Pelizaeus Merzbacher-like disease, PMLD). For a standardised intraindividual follow-up and for comparison of the degree of hypomyelination, we have applied a newly developed semiquantitative myelination score on a total of 18 MRI series of 4 PMD and 4 PMLD patients. We found severe hypomyelination (< 50 % of normal) in 2 PMD and in 2 PMLD patients, moderate hypomyelination (< 75 % of normal) in 2 PMD and mild hypomyelination (> 75 % of normal) in 2 PMLD patients. Our score revealed a clear correlation between the degree of hypomyelination and the severity of clinical handicap in PMD but not in PMLD patients. MRS showed heterogeneous cerebral metabolite patterns in both patient groups and seems to reflect a mixture of unspecific changes due to primary hypomyelination and secondary gliosis and demyelination. Neither by MRI nor by MRS were patterns found that would allow differentiation between PMD and PMLD patients.
Adolescent↗
Feasibility of MR urography in neonates and infants with anomalies of the upper urinary tract.
The aim of this study was to evaluate the feasibility and diagnostic potential of dynamic MR urography (MRU) in neonates and infants with sonographically detected abnormalities of the upper urinary tract. Thirty infants (age range 5 days to 3 years, mean age 7.9 months; male:female: 22:8) underwent MRU using T2 and contrast-enhanced dynamic T1-weighted sequences. The results were compared with the findings of ultrasound ( n=30), intravenous urography (IVU, n=19) and/or scintigraphy ( n=25) based on the criteria suggestive of obstructive uropathy. Oral sedation was sufficient to perform MRU with diagnostic quality in 20 of 21 patients younger than 1 year; 9 older patients needed intravenous sedation. Diagnosis of the 66 renal units (58 kidneys, 29 successful examinations) included normal systems (contralateral units), duplex systems, vesico-ureteral reflux, obstructive megaureter, ureteropelvic junction obstruction and accompanying renal parenchymal disease, with complex pathology in 10 patients. Magnetic resonance urography demonstrated anatomy better than IVU, particularly the renal parenchyma, (ectopic) ureters, and poorly functioning dilated systems. Magnetic resonance urography was superior to US in showing ureteral pathology. Tiny cysts in dysplastic kidneys were better seen by US. Gadolinium-enhanced dynamic MRU allowed accurate assessment of obstruction applying IVU criteria. Here MRU matched IVU results, and most of the scintigraphic findings. Magnetic resonance urography can be performed in young infants with diagnostic quality using oral sedation. Magnetic resonance urography correctly depicts anatomy and allows assessment of the urinary tract better than US and IVU, with additional functional information. Magnetic resonance urography thus has the potential to replace IVU for many indications.
Feasibility Studies↗
Temporal organization of multi-whisker contact in rats.
Previous work has established that during exploration and discrimination, rats move their whiskers at frequencies between 6 and 12 Hz and that whisking frequency changes during contact. One critical component of any tactile system is contact. In the rat whisker system, such contacts may involve one or more vibrissa in the whisker array and contact duration of each whisker may vary over a considerable range, depending upon the behavioral context. However, little is known about the variables controlling contact duration or about the temporal relationships among contacts by adjacent whiskers. To address these issues head fixed rats were trained to touch a piezo-contact-sensor with the shaft of their whiskers (Bermejo and Zeigler, Somatosens Mot Res 17: 373-377, 2000). During the task, whisker movements and contacts were monitored with a high-speed camera at 500 frames/s and stored on videotape. To facilitate analysis, animals had their whiskers selectively trimmed. Data are reported from animals with C1 & C2, D1 & D2, or Arc2 (E2, D2, C2, B2) whiskers intact. For both row and arc animals, when just a single whisker touched the sensor the duration of contact was significantly shorter than when multiple whiskers made contact. When multiple whiskers made contact, onset was rarely simultaneous. Furthermore, in row-intact animals, contact progressed in an orderly fashion such that the rostral whisker in a row made contact first followed 24 ms (SE = 1.9 ms) later by the caudal whisker. When contact reversed the caudal whisker lifted off first, followed by the rostral whisker. Thus, the order in which whiskers touch an object regulates contact duration: the first whisker to touch the sensor stays in contact longer than any other whisker. The temporal discharge properties of neurons in the trigeminal system are expected to reflect position of whiskers on the nose.
Animals↗
Magnetic resonance diffusion tensor imaging for characterizing diffuse and focal white matter abnormalities in multiple sclerosis.
High-resolution diffusion tensor imaging (DTI) was performed in 14 patients with clinically definite multiple sclerosis (MS) and the trace of the diffusion tensor ( ) and the fractional anisotropy (FA) were determined in normal appearing white matter (NAWM) and in different types of focal MS lesions. A small but significant increase of the in NAWM compared to control white matter ((840 +/- 85) x 10(-6) mm(2)/sec vs. (812 +/- 59) x 10(-6) mm(2)/sec; P < 0.01) was found. In addition, there was a significant decrease in the FA of normal-appearing regions containing well-defined white matter tracts, such as the genu of the internal capsule. In non-acute lesions, the of T(1)-hypointense areas was significantly higher than that of T(1)-isointense lesions ((1198 +/- 248) x 10(-6) mm(2)/sec vs. (1006 +/- 142) x 10(-6) mm(2)/sec; P < 0. 001), and there was a corresponding inverse relation of FA. Diffusion characteristics of active lesions with different enhancement patterns were also significantly different. DTI with a phase navigated interleaved echo planar imaging technique may be used to detect abnormalities of isotropic and anisotropic diffusion in the NAWM and selected fiber tracts of patients with MS throughout the entire brain, and it demonstrates substantial differences between various types of focal lesions.
Adult↗
Echo-enhanced color Doppler sonography in children and adolescents.
Fifty-one patients, with a range of underlying pathologic conditions, were studied prospectively to assess the diagnostic value of echo-enhanced color Doppler sonography in the pediatric and adolescent population Their diagnoses included various tumors, vascular disorders, cerebral bleeding, pathologic conditions of small parts, and focal lesions of parenchymal organs. All patients underwent color Doppler sonography before proceeding to echo-enhanced color Doppler sonography. Diagnoses were confirmed by additional imaging (computed tomography, magnetic resonance imaging, angiography, and scintigraphy) performed as appropriate, with or without histologic study. An additional 20 children did not proceed to echoenhanced color Doppler sonography as color Doppler sonography alone was found to be sufficiently diagnostic. Levovist (SHU 508A), a contrast agent based on galactose-encapsulated air microbubbles, is approved for pediatric applications in Austria and was used as the echo-enhancing agent. Echo-enhanced color Doppler sonography was performed a total of 63 times in 51 patients (mean age, 9.8 years). Compared to color Doppler sonography, echo-enhanced color Doppler sonography either detected or enhanced visualization of pathologic conditions in 55 investigations (87.3%), yielding an overall accuracy of 95.2% (sensitivity, 95%), versus 65.7% with color Doppler sonography. One spinal arteriovenous malformation, one cerebral cavernoma, and one liver lesion were missed. The contrast material was easy to administer; no adverse reactions were observed. We conclude that echoenhanced color Doppler sonography is beneficial in pediatric sonography. It enhances visualization of vessels and perfusion, thus offering a nonionizing imaging tool for detection and follow-up evaluation of pathologic conditions with disturbed vasculature in specific cases. In infants and in persons with superficial lesions it did not offer significant advantages over color Doppler sonography.
Adolescent↗
Idiopathic sclerotic inflammation of the orbit with left optic nerve compression in a patient with multifocal fibrosclerosis.
We present the MR imaging findings in a 43-year-old male patient with bilateral idiopathic sclerosing inflammation of the orbit. Bilateral enhancing retrobulbar masses, with concentric compression of the retrobulbar segment of the left optic nerve, were seen. MR imaging proved to be the only means to distinguish between the different intraorbital structures and to determine the exact site of optic nerve compression. To our knowledge, this is the first documented case of MR imaging findings of this entity.
Adult↗
T1 imaging using phase acquisition of composite echoes.
A new magnetic resonance method for T1 imaging is presented. It is based on the simultaneous acquisition of a spin echo and a phase-shifted, stimulated echo. The phase of this composite echo image is modulated heavily by the spin-lattice relaxation time T1, whereas spin density and T2 do not influence the phase information. This phase information can be assigned easily to corresponding T1 values. Although this method is sensitive to radiofrequency inhomogenities, phantom studies showed that high precision and reasonable accuracy of T1 determination can be achieved. Moreover, this method was found to be very robust, because no fitting is required. T1 imaging of the human brain was performed to confirm the in vivo utility of this method.
Adult↗
Diffusion-weighted imaging with navigated interleaved echo-planar imaging and a conventional gradient system.
PURPOSE: To demonstrate the technical feasibility and precision of a navigated diffusion-weighted (DW) MR imaging method with interleaved echo-planar imaging and test its diagnostic sensitivity for detection of ischemic stroke. MATERIALS AND METHODS: Apparent diffusion coefficient (ADC) measurements were performed in phantoms, and six healthy adult volunteers were examined to determine intrasubject (precision) and intersubject (reference range) variations in absolute ADC and relative ADC (rADC) measurements. DW imaging maps and lesion rADC values were also obtained in 34 consecutive stroke patients to evaluate the sensitivity and reliability of DW-interleaved echo-planar imaging for detection of ischemic brain damage. RESULTS: Phantom and volunteer ADC values were in excellent agreement with published data. The intrasubject variation of rADC was 6.2%. The ADC precision ranged from 6.5% in the subcortical white matter in the frontal lobe to 12.9% in the head of the caudate nucleus. Interleaved echo-planar imaging enabled rapid acquisition of high-quality images of the entire brain without substantial artifacts. Within the 1st week, the sensitivity of DW-interleaved echo-planar imaging for detection of acute infarction was 90% (18 of 20 true-positive studies) and independent of lesion location. CONCLUSION: DW-interleaved echo-planar imaging with phase navigation and cardiac triggering is robust, reliable, and fast. With high sensitivity for detection of early ischemic infarction, it is useful for examining stroke patients by using MR systems with conventional gradient hardware.
Adult↗
Intrathalamic connections: a new way to modulate cortical plasticity?
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Animals↗
Functional magnetic resonance imaging of human renal allografts during the post-transplant period: preliminary observations.
Graft dysfunction is a common occurrence during the first weeks following renal transplantation. The current study was designed to evaluate the potential of renal magnetic resonance (MR) perfusion imaging to differentiate acute allograft rejection (AAR) from acute tubular necrosis (ATN) during the post-transplant period. Twenty-three consecutive patients with clinically suspected ATN and/or AAR and eight consecutive control patients (asymptomatic, serum creatinine concentration < 1.5 mg/dL) underwent MR perfusion imaging of the renal allograft within 64 days after transplantation. Histopathology was obtained in all cases with clinical suspicion of ATN or AAR. Sixty sequential fast gradient-recalled-echo MR images were acquired in each patient after intravenous administration of gadolinium-DTPA (0.1 mmol/kg). Histopathology revealed 6 patients with pure AAR, 4 patients with a combination of AAR and ATN, 12 patients with ATN and 1 patient with normal findings. Kidney graft recipients with normal renal function showed a moderate increase in signal intensity (SI) of the renal cortex and medulla after administration of contrast agent followed by an immediate and short decrease in SI of the medulla (biphasic medullary enhancement pattern). The increase in cortical SI of patients with AAR was significantly smaller (61 +/- 4% increase above baseline) than that measured in normal allografts (136 +/- 9% increase above baseline) (p < 0.05) and patients with ATN (129 +/- 3% increase above baseline) (p < .05). Patients with ATN had a slightly delayed and diminished cortical enhancement and an uniphasic and lesser medullary enhancement pattern compared to that observed in normal allografts (p < 0.05). A close correlation (r = 0.72) was found between serum creatinine concentration levels and changes in SI. Thus, MR imaging results and histopathology were in agreement in 22 of 23 patients (96%). MR perfusion imaging of renal allografts can be used to noninvasively differentiate ATN from AAR during the post-transplant period, and may also be helpful in cases were covert AAR is superimposing ATN during a phase of anuria. Patients with ATN can be separated from normals in the majority of cases as reflected by an uniphasic medullary enhancement pattern.
Adult↗
Simultaneous spinal and intracranial chronic subdural hematoma. Case illustration.
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Cauda Equina↗
Differentiation of delayed kidney graft function with gadolinium-DTPA-enhanced magnetic resonance imaging and Doppler ultrasound.
RATIONALE AND OBJECTIVES: The authors differentiate acute tubular necrosis from transplant rejection in patients with delayed kidney graft function using gadolinium (Gd)-DTPA enhanced magnetic resonance (MR) imaging. METHODS: Twenty-four patients after renal transplantation (10 with normal graft function, 14 with delayed graft function) underwent conventional and Doppler sonography and MR imaging examination after bolus application of Gd-DTPA. Within a time period of 512 seconds, 39 single-slice MR images were obtained. Measurements of signal intensity in three regions of interests (cortex, medulla, renal pelvis) resulted in a graphic description of the dynamics of the contrast enhancement. The time between the start of the scan and the peaks of the curves was measured. RESULTS: In patients with normal graft function the curves reached the peaks between 39 and 55 seconds (cortex), 44 and 61 seconds (medulla), and between 161 and 318 seconds (renal pelvis). Six patients with acute tubular necrosis showed normal values for the curves 1 and 2 but markedly prolonged time for curve 3 (between 420 and 512 seconds). In all patients with histologically proven transplant rejection, the peaks of all curves were not reached before the ends of the scans. CONCLUSION: The authors' preliminary results suggest that MR imaging seems to be a sensitive, noninvasive diagnostic tool to differentiate acute tubular necrosis from transplant rejection in the critical early postoperative period.
Adult↗
Staging of cervical carcinomas. Comparison of body-coil magnetic resonance imaging and endorectal surface coil magnetic resonance imaging with histopathologic correlation.
RATIONALE AND OBJECTIVES: The authors evaluate the accuracy of magnetic resonance (MR) imaging with body coil and endorectal surface coil techniques in the staging of cervical carcinomas and compare these results with those obtained with clinical staging (International Federation of Gynecology and Obstetrics [FIGO] classification) and postsurgical histopathology. METHODS: Fifteen patients (average age, 48.6 years) with biopsy-proved cervical cancer were included in the study. After clinical staging (FIGO classification), MR imaging with body coil (BCMR) and subsequently with endorectal surface coil (ECMR) was performed. Using a 1.5-Tesla unit, axial and sagittal proton density weighted and spin echo T2-weighted and fast spin echo T2-weighted sequences were obtained with body and endorectal surface coil. During imaging analysis, special attention was paid to the uterine zones, the vaginal fornix, and the parametrial tissue. Ten patients were treated surgically (postsurgical histopathology was considered the gold standard), five patients, all clinically staged IIIb, underwent primary radiation therapy. RESULTS: Clinical staging with FIGO classification was accurate in 12 of 15 patients, and understaged in 2 and overstaged in 1 patient. Body coil MR showed accurate staging in 13 of 15 patients. Using this technique, understaging of 2 patients, both with only minimal tumor infiltration depth (< 8 mm), was performed. Endorectal surface coil MR was accurate in 14 of 15 patients missing minimal parametrial tumor infiltration in 1 patient. Histopathology (n = 10) revealed 3 patients with tumor stage T1b, 2 with stage T2a, and 5 patients with stage T2b. CONCLUSIONS: Although suggested by only a small number of patients, ECMR appears to be the most accurate modality for staging cervical carcinomas but seems to be unreliable in the detection of minimal tumor infiltration.
Adult↗
Magnetic resonance imaging in patients with gestational trophoblastic disease.
RATIONALE AND OBJECTIVES: The authors describe the magnetic resonance (MR) imaging characteristics in patients with gestational trophoblastic disease (GTD) before and after therapy and to correlate these findings with human gonadotropin levels and the specific histology of GTD. METHODS: Thirteen women (mean age, 30.1 years) with elevated human chorionic gonadotropin (HCG) levels and histologically proven GTD underwent MR examinations of the pelvis. Magnetic resonance imaging was performed on a 1.5-tesla unit. Axial and sagittal proton density-weighted and T2-weighted and sagittal T1-weighted sequences were obtained. Four patients underwent follow-up studies after 4 and 8 weeks to monitor the response to therapy. Gestational trophoblastic disease was histologically proven with curettage in 11 patients and with hysterectomy in two cases. RESULTS: Nine patients had a diffusely enlarged uterus with pathologic signal intensities. In four patients, a focal tumor mass was observed. All patients showed loss of the zonal anatomy of the uterus in at least one local area. In 11 patients, no uterus zones could be identified throughout the entire uterus. Pathologic dilated tumor vessels were evident in all patients. In all four cases in which follow-up imaging studies were obtained, uterus size, signal intensities, identification of uterus zones, and uterus vessels returned to normal. CONCLUSION: Magnetic resonance imaging shows trophoblastic tumor infiltration as diffuse uterus enlargement, focal tumor masses, loss of zonal anatomy of the uterus, and pathologic uterine vasculature; this seems to be the most reliable MR imaging finding in patients with GTD. No correlation was found between MR imaging changes and HCG levels or specific histologic types of GTD.
Adolescent↗