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O P Eldevik

Publications and source records attributed to O P Eldevik.

At least 19 recordsLinked to original sources
PubMed2005

Spinal cord magnetic resonance imaging in autosomal dominant hereditary spastic paraplegia.

Hereditary spastic paraplegia (HSP) is a genetically heterogeneous group of neurodegenerative disorders characterized by progressive lower extremity weakness and spasticity. HSP pathology involves axonal degeneration that is most pronounced in the terminal segments of the longest descending (pyramidal) and ascending (dorsal columns) tracts. In this study, we compared spinal cord magnetic resonance imaging (MRI) in 13 HSP patients with four different types of autosomal dominant hereditary spastic paraplegia (SPG3A, SPG4, SPG6, and SPG8) with age-matched control subjects. The cross-section area of HSP subjects at cervical level C2 was 59.42 +/- 12.57 mm2 and at thoracic level T9 was 28.58 +/- 5.25 mm2. Both of these values were less than in the healthy controls (p < 0.001). The degree of cord atrophy was more prominent in patients with SPG6 and SPG8 who had signs of severe cord atrophy (47.60 +/- 6.58 mm2 at C2, 21.40 +/- 2.4 mm2 at T9) than in subjects with SPG3 and SPG4 (66.0 +/- 8.94 mm2 at C2, p < 0.02; 31.75 +/- 2.76 mm2 at T9, p < 0.001). These observations indicate that spinal cord atrophy is a common finding in the four genetic types of HSP. Spinal cord atrophy was more severe in SPG6 and SPG8 HSP subjects than in other types of HSP we studied. This may suggest a different disease mechanism with more prominent axonal degeneration in these two types of HSP when compared with HSP due to spastin and atlastin mutations.

Adult↗
PubMed2002

Spastic paraplegia, ataxia, mental retardation (SPAR): a novel genetic disorder.

OBJECTIVE: To describe a kindred with a dominantly inherited neurologic disorder manifested either as uncomplicated spastic paraplegia or ataxia, spastic paraplegia, and mental retardation. METHODS: Neurologic examinations and molecular genetic analysis (exclusion of known SCA and HSP genes and loci; and trinucleotide repeat expansion detection [RED]) were performed in six affected and four unaffected subjects in this family. MRI, electromyography (EMG), and nerve conduction studies were performed in three affected subjects. RESULTS: The phenotype of this dominantly inherited syndrome varied in succeeding generations. Pure spastic paraplegia was present in the earliest generation; subsequent generations had ataxia and mental retardation. MRI showed marked atrophy of the spinal cord in all patients and cerebellar atrophy in those with ataxia. Laboratory analysis showed that the disorder was not caused by mutations in genes that cause SCA-1, SCA-2, SCA-3, SCA-6, SCA-7, SCA-8, and SCA-12; not linked to other known loci for autosomal dominant ataxia (SCA-4, SCA-5, SCA-10, SCA-11, SCA-13, SCA-14, and SCA-16); and not linked to known loci for autosomal dominant hereditary spastic paraplegia (HSP) (SPG-3, SPG-4, SPG-6, SPG-8, SPG-9, SPG-10, SPG-12, and SPG-13) or autosomal recessive HSP SPG-7. Analysis of intergenerational differences in age at onset of symptoms suggests genetic anticipation. Using RED, the authors did not detect expanded CAG, CCT, TGG, or CGT repeats that segregate with the disease. CONCLUSIONS: The authors describe an unusual, dominantly inherited neurologic disorder in which the phenotype (pure spastic paraplegia or spastic ataxia with variable mental retardation) differed in subsequent generations. The molecular explanation for apparent genetic anticipation does not appear to involve trinucleotide repeat expansion.

Adolescent↗
PubMed2001

Sensory nerve somatosensory evoked potentials as add-on diagnostic procedure to imaging procedures in patients with sciatica.

The aim of the present study was to evaluate the ability of sensory nerve somatosensory evoked potentials (SEP) to discriminate between lumbar spine computed tomography (CT) findings with and without relevance for the radiating sensory symptoms in patients with sciatica in whom myelography does not have such discriminatory capacity. Forty consecutive sciatic patients in whom CT without intrathecal contrast showed degenerative changes which did not cause probable compression in at least one symptomatic nerve root, or caused probable compression in at least one asymptomatic nerve root, and in whom there were corresponding discrepancies between the radiating sensory symptoms and myelographic nerve root compression, were studied. Sensory nerve SEP representing nerve roots L4, L5 and S1, were performed in all patients. The sensory nerve conduction velocity (SNCV) and the amplitude of the sensory nerve action potential (SNAP) were recorded from the stimulated nerves. The odds ratios (OR 95% CI) of the association of positive SEP to symptomatic nerve roots were 24.0 (4.8 to 54.5) in nerve roots with probable and 39.0 (5.9 to 258.9) with possible CT compression. The corresponding associations between myelography and sciatic symptoms were not statistically significant. Comparisons of SNCVs and SNAP amplitudes did not indicate that postganglionic nerve dysfunction contributed to the sensory symptoms or to the SEP results. SEP examination may be used to discriminate between CT findings with and without relevance to the radiating sensory symptoms in patients with sciatica in whom myelography does not show this discriminatory capacity.

Adolescent↗
PubMed2000

Improving postoperative MR imaging of pituitary macroadenomas: comparison of full and reduced dose of gadopentetate dimeglumine.

The aim of this study was to evaluate the efficacy of contrast-medium (CM)-ehanced MR imaging of operated pituitary macroadenomas with reduced dose of gadopentetate dimeglumine. In a prospective study 18 patients were examined with coronal T1-weighted MR imaging prior to and following intravenous CM injections. Two sets of contrast-enhanced coronal images were obtained in each patient; the first set after 50% of the recommended dose of 0.1 mmol/kg body weight (b.w.) had been administered, and the second set immediately after additional CM had been given to make up a total dose of 0.1 mmol/kg b.w. The images were evaluated by three neuroradiologists. The SIPAP classification system was used to evaluate tumour extension, whereas tumour margin conspicuity was scored using an arbitrary scale of 1-5 (1 = indistinct, 5 = well defined). Signal intensity measurements obtained from the most enhancing part of the adenomas demonstrated increased enhancement with increased CM dose. Tumour delineation scores were significantly better on the reduced- and full-dose images than on pre-CM injection images, but, with one exception, tumour extension was identified as the same on all imaging sequences. Postoperative MR imaging of large macroadenoma residues can routinely be performed without intravenous CM. When CM is indicated a reduced dose of gadopentetate dimeglumine should provide sufficient diagnostic information.

Adenoma↗
PubMed2000

Acoustic droplet vaporization for therapeutic and diagnostic applications.

A phase shift droplet emulsion is introduced as an aid to unusual ultrasound (US) applications. The transpulmonary droplet emulsion (90% < 6 microm diameter) is made by mixing saline, bovine albumin and dodecafluoropentane. It has been observed that an acoustic pressure threshold exists, above which the droplets vaporize into bubbles approximately 25 times the original diameter. For frequencies between 1.5 and 8 MHz, the threshold decreases from 4.5 to 0.75 MPa peak rarefactional pressure. This paper presents preliminary results for droplet preparation and their evaporation as a function of applied acoustic pressure and frequency, as well as simulations of the lifetime of these gas bubbles based on gas diffusion. In vivo experiments were simulated by the evaporation of droplets in blood flowing under attenuating material. We propose that this agent might be useful for tissue occlusion in cancer treatment, as well as for phase aberration corrections in acoustic imaging.

Albumins↗
PubMed2000

Sedation and general anaesthesia in children undergoing MRI and CT: adverse events and outcomes.

Quality assurance data were collected prospectively for children who were sedated (n = 922) or given general anaesthesia (n = 140) for magnetic resonance imaging (MRI) or computerized tomography (CT). The data included patient characteristics, concurrent medication, adequacy of sedation, adverse events and requirement for escalated care. The quality of scans was evaluated. Reasons for preselection of general anaesthesia included previously failed sedation (28%), potential for failed sedation (32%) and perceived medical risk (14%). Hypoxaemia occurred in 2.9% of sedated children, and was more common in children classified as ASA III or IV. Sedation was inadequate for 16% of children and failed in 7%. Failed sedation was associated with greater age (P = 0.009), higher ASA status (P = 0.04) and use of benzodiazepines as sole sedatives (P < 0.03). More of the children who underwent general anaesthesia were ASA III or IV than sedated children, yet the procedure was successful in all the children who underwent general anaesthesia, with one incident of laryngospasm. Excessive motion was noted in 12% of scans of sedated children and 0.7% of those completed with general anaesthesia. We conclude that sedation of children for MRI and CT is associated with risks of hypoxaemia and of inadequate or failed sedation. These adverse events were more likely to occur in older children, those with a higher ASA status and those in whom benzodiazepines had been used as sole sedatives. For a preselected high-risk group of children, general anaesthesia may make MRI and CT scans more successful with minimal adverse events.

Adolescent↗
PubMed2000

Clinical consequences of misinterpretations of neuroradiologic CT scans by on-call radiology residents.

BACKGROUND AND PURPOSE: Studies have looked at the accuracy of radiologic interpretations by radiology residents as compared with staff radiologists with regard to emergency room plain films, emergency room body CT scans, and trauma head CT scans; however, to our knowledge, no study has evaluated on-call resident interpretations of all types of neuroradiologic CT scans. Both as a part of our departmental quality control program and to address concerns of clinical services about misinterpretation of neuroradiologic CT scans by on-call radiology residents, we evaluated the frequency of incorrect preliminary interpretations of neuroradiologic CT scans by on-call radiology residents and the effect of such misinterpretations on clinical management and patient outcome. METHODS: As determined by the staff neuroradiologist the next day, all potentially clinically significant changes to preliminary reports of emergency neuroradiologic CT scans rendered by on-call radiology residents were recorded over a 9-month period. A panel of neuroradiologists reviewed and graded all the changed cases by consensus. An emergency department staff physician reviewed medical records of all submitted cases to determine clinical consequences of the misinterpretations. RESULTS: Significant misinterpretations were made in 21 (0.9%) of 2388 cases during the study period. There was a significant change in patient management in 12 of the cases, with a potentially serious change in patient outcome in two cases (0.08%). CONCLUSION: On-call radiology residents have a low rate of significant misinterpretations of neuroradiologic CT scans, and the potential to affect patient outcome is rare.

Adolescent↗
PubMed1999

Phenotypic analysis of autosomal dominant hereditary spastic paraplegia linked to chromosome 8q.

OBJECTIVE: To describe clinical, electrophysiologic, neuroimaging, and muscle biopsy features in a hereditary spastic paraplegia (HSP) kindred linked to a new HSP locus on chromosome 8q. BACKGROUND: HSP is a genetically diverse group of disorders characterized by insidiously progressive spastic weakness in the legs. We recently analyzed a Caucasian kindred with autosomal dominant HSP and identified tight linkage to a novel HSP locus on chromosome 8q23-24. METHODS: Clinical analysis, nerve conduction studies, electromyography, somatosensory evoked potentials, MRI of brain and spinal cord, and muscle biopsy for mitochondrial analysis were performed in members of the first HSP kindred linked to chromosome 8q. RESULTS: Fifteen individuals showed insidiously progressive spastic paraparesis beginning between ages 22 and 60 years (average, 37.2 years). Spinal cord MRI in 1 moderately affected subject showed significant atrophy of the thoracic spinal cord as determined by cross-sectional area measurements. Somatosensory evoked potential recording, electromyography, nerve conduction studies, and muscle biopsy, including histochemical and biochemical analysis of mitochondrial function, were normal. CONCLUSIONS: The phenotype in this family is that of typical, but severe, uncomplicated HSP. Other than apparently increased severity, there were no clinical features that distinguished this family from autosomal dominant HSP linked to loci on chromosomes 2p, 14q, and 15q. This clinical similarity between different genetic types of autosomal dominant HSP raises the possibility that genes responsible for these clinically indistinguishable disorders may participate in a common biochemical cascade. Normal results of muscle histochemical and biochemical analysis suggest that mitochondrial disturbance, a feature of chromosome 16-linked autosomal recessive HSP due to paraplegin gene mutations, is not a feature of chromosome 8q-linked autosomal dominant HSP and may not be a common factor of HSP in general.

Adult↗
PubMed1998

Contrast enhancement in the craniopharyngioma cyst wall caused by irradiation.

PURPOSE: To report the occurrence, degree, frequency, and duration of contrast enhancement in the craniopharyngioma cyst wall as caused by irradiation. MATERIAL AND METHODS: Eight patients with cystic craniopharyngiomas had comparable CT or MR studies before and after either external irradiation of the cyst (n = 5) or 32P instillation into the cyst (n = 3). RESULTS: A minimal to marked increase in cyst-wall enhancement was seen at 66-157 days after 32P instillation in 3/3 cases and at 112-495 days after external irradiation in 3/5 cases. The increased enhancement was always associated with a variable interim increase in the thickness of the enhanced cyst wall. CONCLUSION: CT or MR imaging after the irradiation of cystic craniopharyngiomas usually demonstrated an increase in thickness and enhancement in the cyst wall. Such changes may be due to the irradiation alone and do not necessarily represent infection or increased neoplastic activity. The timing is uncertain as to the earliest possible development of such changes and their maximum duration, but they were seen as early as 66 days post-irradiation and as late as 495 days post-irradiation.

Adult↗
PubMed1997

P1-latency interroot comparison enhances the validity of scalp-recorded somatosensory-evoked potentials to diagnose nerve root dysfunction in sciatica.

STUDY DESIGN: A prospective validity study was done of scalp-recorded somatosensory-evoked potentials as a diagnostic procedure to show lumbosacral radiculopathy in 100 consecutive patients with unilateral or bilateral sciatica. OBJECTIVE: To determine the validity gained by the use of P1-latency interroot comparison to show P1-latency prolongation. SUMMARY OF THE BACKGROUND DATA: The validity of scalp-recorded somatosensory-evoked potentials in diagnosing lumbosacral radiculopathy has been debated and is uncertain. METHOD: Sensory nerves representing nerve roots L4, L5, and S1 were stimulated bilaterally. Height-corrected P1-latency, two new P1-interroot comparison-based criteria, and absence of P1 were studied. The gold standard was defined as clinically-involved nerve roots with radiologic nerve root compression. The false-positive nerve root compression rate was determined, and the gold standard was corrected accordingly. Clinically relevant cut-off values were defined by multilevel likelihood ratio analysis. RESULTS: The positive and negative likelihood ratios of P1-latency prolongation were 6.79 and 0.53, respectively, for the gold standard, and 10.57 and 0.21, respectively, for the corrected gold standard. The validity was not reduced when scalp-recorded, somatosensory-evoked potentials were blinded to the radiologic results. Absence of P1 was associated to the gold standard and the corrected gold standard. Compared with the combined use of P1-latency interside difference and height-corrected latency, the combination of P1-interroot comparison and height-corrected P1-latency increased the sensitivity by 20% for the gold standard and 32% for the corrected gold standard, and when absent P1 was added, the overall sensitivity was 53% for the gold standard and 81% for the corrected gold standard. The corresponding specificity was 92%, and in asymptomatic nerve roots it was 98%. CONCLUSION: The P1-interroot comparison permits the use of scalp-recorded somatosensory-evoked potentials as a contributory "rule in" procedure in patients with sciatica.

Adolescent↗
PubMed1996

Magnetic resonance imaging of normal meningeal enhancement at 1.5 T.

RATIONALE AND OBJECTIVES: We examined patterns of intracranial meningeal enhancement on gadolinium chelate contrast media-enhanced 1.5-T spin-echo magnetic resonance (MR) imaging and developed criteria that might be useful for distinguishing between normal and abnormal meningeal enhancement. METHODS: The convexity, falx cerebri, tentorium cerebelli, and suprasellar cistern regions of 204 patients were prospectively evaluated for contrast enhancement with a grading system ranging from 0 (no enhancement) to 5 (diffuse, irregular, thickened enhancement). Meningeal findings were correlated with other MR abnormalities and pertinent clinical histories that have been associated previously with meningeal enhancement. RESULTS: Short-segment convexity meningeal enhancement was commonly seen and most likely represents intravascular contrast material in normal meningeal vessels. Such enhancement did not correlate with the presence of other MR abnormalities. Long-segment (> 3 cm) or diffuse convexity meningeal enhancement did correlate with other significant MR abnormalities and pertinent clinical history. Fine linear falcine and tentorial meningeal enhancement, as an isolated finding, did not correlate with other MR or clinical abnormalities. The suprasellar cistern and ventricular walls were rarely enhanced. CONCLUSION: Short-segment convexity meningeal contrast enhancement is a normal finding representing normal vascular structures. More extensive convexity meningeal enhancement is abnormal and should prompt careful examination of the remainder of an MR image as well as the patient's clinical history for an etiology of the enhancement.

Adolescent↗
PubMed1996

Neuroradiology.

Explore the source record for details and available documents.

Humans↗
PubMed1996

Pre- and postoperative MR imaging of craniopharyngiomas.

PURPOSE: To compare the pre- and postoperative MR appearance of craniopharyngiomas with respect to lesion size, tumour morphology and identification of surrounding normal structures. MATERIAL AND METHODS: MR images obtained prior to and following craniopharyngioma resection were evaluated retrospectively in 10 patients. Tumour signal characteristics, size and extension with particular reference to the optic chiasm, the pituitary gland, the pituitary stalk and the third ventricle were evaluated. RESULTS: Following surgery, tumour volume was reduced in all patients. In 6 patients there was further tumour volume reduction between the first and second postoperative images. Two of these patients received radiation therapy between the 2 postoperative studies, while 4 had no adjuvant treatment to the surgical intervention. There was improved visualization of the optic chiasm in 3, the pituitary stalk in one, and the third ventricle in 9 of the 10 patients. The pituitary gland was identified preoperatively only in one patient, postoperatively only in another, pre- and postoperatively in 5, and neither pre- nor postoperatively in 3 patients. In 3 patients MR imaging 0-7 days postoperatively identified tumour remnants not seen at the end of the surgical procedure. The signal intensities of solid and cystic tumour components were stable from pre- to the first postoperative MR images. Optic tract increased signal prior to surgery was gone 28 days postoperatively in one patient, but persisted on the left side for 197 days after surgery in another. CONCLUSION: Postoperative MR imaging of craniopharyngiomas demonstrated tumour volume reduction and tumour remnants not seen at surgery. Early postoperative MR imaging of craniopharyngiomas may overestimate the size of residual tumour. Improved visualization of peritumoral structures may be achieved.

Adult↗
PubMed1996

Craniopharyngioma: radiologic and histologic findings and recurrence.

PURPOSE: To identify the CT and MR characteristics of craniopharyngiomas, to evaluate the histologic types of craniopharyngioma, and to compare the radiologic/histologic appearance and type of therapy with tumor recurrence. METHODS: We reviewed the records of 45 patients with craniopharyngiomas for which surgical specimens (n = 45), preoperative MR or CT studies (n = 27), or other MR or CT studies or reports (n = 18) were available. Radiologic appearance, histologic morphology, treatment, and tumor recurrence were studied. RESULTS: Adamantinomatous epithelium was found in 40 of 45 surgical specimens, keratin in 34 of 45, and squamous epithelium in 11 of 45. A continuum of mixed morphology rather than distinct subtypes of tumors was found. The radiologic appearance did not correlate with the histologic features. No statistically significant difference was found between children and adults with respect to tumor size, calcification, histology, or tumor recurrence. Patients treated with radiation after subtotal resection had far fewer tumor recurrences (n = 3) than patients treated with surgery alone (n = 18). CONCLUSION: Craniopharyngiomas could not be divided into distinct histologic types. No differentiating radiologic or histologic characteristics could be established for craniopharyngiomas in children versus adults. Radiation treatment was strongly associated with tumor regression or lack of recurrence.

Adolescent↗
PubMed1995

Craniopharyngioma identification by CT and MR imaging at 1.5 T.

To compare the detectability of craniopharyngiomas by CT and MR imaging, preoperative CT and MR studies obtained within 16 days of each other were evaluated retrospectively in 9 patients. MR imaging demonstrated cystic and solid tumor components in all 9 tumors, and enhancement in the 7 tumors that were studied after contrast medium injection. MR imaging demonstrated a signal void consistent with calcification in 4 patients. Combining unenhanced and contrast medium-enhanced studies, CT also identified all the tumors. CT demonstrated cysts in 7 lesions, calcification in 7 and enhancement in 6 of the 7 lesions that received i.v. contrast medium. Calcification was better seen by CT than MR imaging, while MR imaging identified cystic tumor components not seen on CT. The contrast medium enhancement pattern was the same with the 2 modalities. MR imaging of the sellar region, including at least one contrast medium-enhanced sequence, should be sufficient in most instances to establish a preoperative diagnosis of craniopharyngioma.

Adult↗
PubMed1995

Esophageal carcinoma metastatic to the brain: clinical value and cost-effectiveness of routine enhanced head CT before esophagectomy.

PURPOSE: To assess the value of screening enhanced head CT before esophagectomy for carcinoma, identify increased risk factor(s) for brain metastases, and determine metastasis incidence. METHODS: Thoracic surgery files of patients undergoing esophagectomies for squamous carcinomas, adenocarcinomas, and undifferentiated carcinomas between January 1984 and March 1993 were reviewed regarding sex, size (length) of neoplasm, and brain metastases. Surgical pathology and tumor registry files also were reviewed. Records of patients with brain metastases were reviewed in detail. RESULTS: Three hundred thirty-four esophagectomies were performed for 230 adenocarcinomas (202 male, 28 female) and 104 squamous carcinomas (61 male, 43 female). In 9 males and 1 female with adenocarcinomas and 1 male and 1 female with squamous carcinomas, brain metastases developed. Surgical pathology files identified 293 additional esophageal carcinomas, including 2 males with adenocarcinomas metastatic to brain. Tumor registry files identified I additional male with brain metastasis from an undifferentiated esophageal neoplasm. No statistically significant preoperative characteristic of esophageal carcinomas with proneness to brain metastases was found, except large size of primary neoplasm. Preoperative screening head CT done on approximately 240 patients who underwent esophagectomies showed no metastases. CONCLUSIONS: Brain metastases from carcinomas of the esophagus are relatively uncommon (3.6% in the esophagectomy cohort). They tend to occur in patients with large primary neoplasm, probably especially adenocarcinomas involving the esophagogastric junction, and with findings of local invasion and lymph node metastases by CT and/or microscopically. It may be reasonable to obtain head CT as a last preoperative staging procedure in such patients. Routine preoperative head CT for staging is not cost effective.

Aged↗
PubMed1994

Craniopharyngiomas--the utility of contrast medium enhancement for MR imaging at 1.5 T.

To evaluate the efficacy of i.v. contrast medium administration in MR imaging at 1.5 T in patients with craniopharyngiomas, MR studies of 10 men and 6 women with pathologically proven craniopharyngiomas were made. The MR images were obtained as 3- to 5-mm-thick coronal (n = 13) or axial (n = 3) Tl-weighted images (T1WI) prior to and following i.v. Gd-DTPA administration. Proton density- (PD) and T2-weighted images (T2WI) were also obtained. Conspicuity of tumor margins, cystic versus solid components, size, location and effect upon adjacent structures were separately characterized in all imaging sequences. In 6 patients contrast medium-enhanced T1WI. PD and T2WI demonstrated cystic tumor components not seen on unenhanced T1WI. There were significant differences (p < 0.004) on 2-tailed Student's t-test comparing tumor conspicuity on contrast medium-enhanced T1WI with unenhanced T1WI, PD and T2WI. Optimal tumor delineation on MR imaging of patients with craniopharyngiomas justifies the use of i.v. contrast medium.

Adolescent↗