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O P Eldevik

Publications and source records attributed to O P Eldevik.

At least 19 recordsLinked to original sources
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↗
PubMed1994

Gadopentetate dimeglumine-enhanced MR of the brain: clinical utility and safety in patients younger than two years of age.

PURPOSE: To evaluate the clinical utility and safety of gadopentetate dimeglumine as a contrast agent for MR of the brain in patients younger than 2 years of age. METHODS: In 125 consecutive patients younger than 2 years of age, MR images obtained before and after gadopentetate dimeglumine administration (0.1 mmol/kg) were independently and prospectively evaluated. After interpreting the unenhanced T1- and T2-weighted images, we rated the utility of contrast administration in each patient as not helpful, helpful, or essential for formulation of the radiologic diagnosis. Ratings were categorized both on the basis of the referring clinical diagnoses and on the basis of a radiologic diagnosis that was established from the clinical history and from the findings on the precontrast and postcontrast T1- and T2-weighted images. Patients' vital signs were recorded, and general medical status was observed for 120 minutes after gadopentetate dimeglumine administration. RESULTS: In no case did gadopentetate dimeglumine permit detection of lesions when precontrast T1- and T2-weighted images were normal. In only 4 of 125 patients were postcontrast images considered essential for establishing the radiologic diagnosis. Abnormal contrast enhancement was radiologically helpful in 20 of 125 patients. Lack of enhancement was considered helpful in 22 of 125 patients. No adverse clinical events or clinically important trends in vital signs were observed after contrast administration. CONCLUSION: The indiscriminate use of contrast agents in the MR imaging of patients younger than 2 years of age is not warranted. Appropriate decisions regarding the use of gadopentetate dimeglumine can be based on the findings in unenhanced T1- and T2-weighted images and on the referring clinical diagnosis.

Brain Diseases↗
PubMed1986

Volumes of pituitary adenomas related to hormone production, duration of symptoms and postoperative outcome.

In the period from December 1978 to February 1986, 292 patients with pituitary adenomas were operated transsphenoidally. We measured tumor volumes from CT scans and pneumoencephalograms. Tumor volumes varied from 0.5 to 160 cm3. The duration of the clinical history varied from 6 months to 24 years. All pituitary hormones were recorded pre- and postoperatively in each patient. We found a positive correlation between tumor size and duration of clinical symptoms, both in hormone producing (active) and non-producing (inactive) adenomas. Among the prolactin and growth-hormone producing adenomas there was also positive correlation between tumor size and hormone levels: small and medium sized hormone producing adenomas (volume 6 cm3 or less), showed normalization of the preoperatively increased hormone levels after surgery. In patients with hormone producing pituitary adenomas larger than 6 cm3, we still found elevated serum prolactin or serum growth-hormone levels postoperatively. This indicates that the largest tumors could not be completely removed surgically. Pituitary tumors should be operated before they reach a volume of 6 cm3. If non-surgical treatment is initiated, the patient has to be closely followed with computed tomography.

Adenoma↗
PubMed1985

Absorption of iohexol from cerebrospinal fluid to blood: pharmacokinetics in humans.

The absorption of iohexol from the subarachnoid space was studied in 9 patients. Serum concentrations of iohexol were measured for a minimum of 24 hours after injection. Peak serum concentrations were observed after 2.2 (1.7-2.7) hours. The half-life of the subsequent decrease in serum concentrations was 3.4 (2.2-7.9) hours. Concentrations of iohexol in cerebrospinal fluid were 0.29-4.3 mg I/ml 24 hours after injection (7 patients). Serum and cerebrospinal fluid concentrations of iohexol are comparable to those found after intrathecal injection of metrizamide.

Adult↗
PubMed1984

Intraoperative gas cisternography and gas dissection in the operative treatment of pituitary tumors. A methodological description.

We have given a methodological description of gas dissection and gas cisternography used during transsphenoidal surgery. 200 consecutive patients with pituitary adenomas or craniopharyngeomas have been operated according to Cushing- Guiot -Hardy's procedure. 68 patients had suprasellar expansions in which gas dissection was used. The operative procedure with technical equipment and staff requirement is reported as well as the combined neurosurgical and neuroradiological techniques.

Adenoma↗
PubMed1983

Lateral C1-2 puncture for cervical myelography. Part III: Historical, anatomic, and technical considerations.

Three significantly different lateral approaches to the cervical subarachnoid space (anterior, midplane, and posterior needle positions) have been previously described for cordotomy and myelography. Experimental lateral C1-2 punctures were performed by each of these three methods in anatomic specimens, cadaver models with reconstituted cerebrospinal fluid pressures, a patient with cerebral death, and to a limited degree in patients undergoing routine cervical myelography. In the cervical region the dura is pushed ahead of the needle, forming a "tent" over the needle tip during C1-2 puncture; the needle projects several millimeters into the spinal canal before penetrating the dura, regardless of the method of entry or needle diameter. The extent of this tenting phenomenon and its relationship to the spinal cord are significantly affected by the needle diameter and position. A posterior technique for lateral C1-2 puncture is described.

Adolescent↗
PubMed1983

Documentation of a new contrast medium for the subarachnoid space. Demands, design and results from the first multicentre trial with iohexol.

The first clinical trial with the non-ionic contrast medium iohexol (Omnipaque) in lumbar myelography was performed as a multicentre investigation of a total of 88 included patients. The design of the comprehensive clinical trial program is presented and the necessity of using such an extensive clinical trial program in the early stage of the investigation is discussed. This comprehensive monitoring did not reveal any serious or persistent side effects. The documentation on the safety of the drug encourages further clinical trials.

Adult↗
PubMed1983

First clinical trial with iohexol in myelography.

This is a report of the first clinical trial with iohexol in lumbar myelography. The investigation was carried out as an open, non-comparative study in 30 patients and was part of a multicentre trial. Iohexol doses of 10 to 15 ml (180 mg I/ml) were used and clinical and laboratory tests were performed before and during 48 h after myelography. Spinal repuncture 6 or 24 h after myelography was done in all patients. Only minor side effects of temporary duration were recorded in 8 patients. No seizures or spikes on EEG were seen. There was no significant increase in CSF parameters such as white cell counts, protein or IgG.

Cerebrospinal Fluid Proteins↗
PubMed1982

A prospective comparison of computed tomography and myelography in the diagnosis of herniated lumbar disks.

Although CT effectively demonstrates normal and herniated intervertebral disks, the value of CT in low back pain has not been adequately evaluated. We compared CT prospectively with myelography in 107 patients referred to Ulleval Hospital Department of Radiology for myelography. Fifty-two patients subsequently had spinal explorations, one patient twice during the study and two patients at two levels. Forty-six CT and 44 myelographic diagnoses agreed perfectly with the operative diagnosis at that level. In 30 disk herniations, there were 29 true-positive CT diagnosis and 28 true-positive myelographic diagnoses. False-negative diagnoses of herniated nucleus pulposus were made twice on myelography and once on CT. In 24 other spinal operations, there were eight false-positive CT and nine false-positive myelographic diagnoses of herniated nucleus pulposus. CT demonstrates lumbar disk disease as effectively as myelography.

Adolescent↗