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Träfflista för sökning "hsv:(MEDICIN OCH HÄLSOVETENSKAP) hsv:(Klinisk medicin) srt2:(1990-1999);srt2:(1996);pers:(Holtås Stig)"

Sökning: hsv:(MEDICIN OCH HÄLSOVETENSKAP) hsv:(Klinisk medicin) > (1990-1999) > (1996) > Holtås Stig

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1.
  • Källén, Kristina, et al. (författare)
  • Preoperative grading of glioma malignancy with thallium-201 single-photon emission CT: comparison with conventional CT
  • 1996
  • Ingår i: AJNR. - 1936-959X. ; 17:5, s. 925-932
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To compare thallium-201 single-photon emission CT with conventional CT in grading the malignancy of gliomas and to determine the reliability of each in tumor assessment. METHODS: We studied 37 patients who had gliomas (31 high grade and 6 low grade) and compared the CT findings with the thallium-201 index, which we defined as tumor uptake relative to the uptake in the contralateral hemisphere. RESULTS: Among the high-grade gliomas, we observed a significant correlation between breakdown volume of the blood-brain barrier and thallium-201 uptake. However, 8 of the high-grade gliomas had low thallium-201 uptake, in the same range as the low-grade gliomas. Of these, 2 were nonenhancing and the other 6 showed ring enhancement on CT scans. Analysis of variance showed no significant difference in thallium-201 indexes between low-grade gliomas and highly malignant (grade II-III) gliomas. Accuracy of thallium-201 imaging was lower (78%) than that of CT (84%) in identifying high-grade gliomas. CONCLUSIONS: Damage to the blood-brain barrier is a prerequisite for uptake of thallium-201 in gliomas. Tumors with central necrotic areas and moderate ring enhancement tend to be underestimated when evaluated by means of thallium-201 scintigraphy. The results indicate a need for caution when interpreting findings on images obtained with thallium-201 single-photon emission CT in preoperative evaluation of brain tumors.
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2.
  • Akeson, P, et al. (författare)
  • MR imaging in recurrent pain after back surgery. A comparative study using standard and high doses of gadolinium contrast agents
  • 1996
  • Ingår i: Acta Radiologica. - 1600-0455. ; 37:6, s. 858-858
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To compare the diagnostic results following injection of (a) a high dose (0.3 mmol/kg b.w.) of gadodiamide injection and (b) the standard dose (0.1 mmol/kg b.w.) of Gd-DTPA, in patients with recurrent symptoms after surgery for lumbar disc herniation. MATERIAL AND METHODS: Twenty patients with recurrent or sustained symptoms after surgery for lumbar disc herniations were examined. MR imaging (0.3 T) was first performed before and after Gd-DTPA at 0.1 mmol/kg b.w., and then within one month (17 patients) or within 3 months (3 patients) before and after gadodiamide injection at 0.3 mmol/kg b.w. The examinations were first evaluated by 2 neuroradiologists blinded to dose but not to patient as the images were presented in pairs. Six months later the same investigators evaluated the examinations again, this time blinded to both dose and patient. RESULTS: At the evaluation in pairs (with the investigators blinded to dose only) the high-dose examinations were considered the most informative (p=0.05). However, at the later evaluation (with the investigators blinded both to dose and patient) no significant difference between high and standard dose was found regarding diagnosis or diagnostic certainty. CONCLUSION: In this study the high-dose contrast enhancement of MR imaging at 0.3 T did not increase the diagnostic information for differentiating between scar and recurrent hernia. The high-dose images were considered more informative when evaluated in pairs, but gave no additional or different information when evaluated separately. The study also indicated that comparisons in pairs should be interpreted with caution.
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3.
  • Albeck, M J, et al. (författare)
  • Billeddiagnostik ved mistanke om lumbal diskusprolaps. En kontrolleret sammenligning af myelografi, CT og magnetisk resonans-billeddannelse
  • 1996
  • Ingår i: Ugeskrift for Læger. - 0041-5782. ; 158:10, s. 1362-1362
  • Tidskriftsartikel (refereegranskat)abstract
    • Eighty patients with monoradicular sciatica were examined by myelography, computed tomography (CT) and magnetic resonance imaging (MRI) and all had subsequent surgery. The images were evaluated by a decision-analytic regret function. The largest amount of diagnostic information was gained from CT followed by MRI and myelography. Myelography was not significantly informative. The results suggest that CT or MRI should be the first choice examination in patients with suspected lumbar disc herniation.
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4.
  • Annertz, Mårten, et al. (författare)
  • MR imaging as the primary modality for neuroradiologic evaluation of the lumbar spine. Effects on cost and number of examinations
  • 1996
  • Ingår i: Acta Radiologica. - 1600-0455. ; 37:3 Pt 1, s. 373-380
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To evaluate the effects on cost, and number of primary and supplementary neuroradiologic examinations, after introducing MR imaging as the primary modality in the evaluation of the lumbar spine. MATERIAL AND METHODS: Two 5-month periods were compared: period 1--before MR; and period 2--after introduction of a 2nd MR device. In period 1, patients were examined with myelography and/or CT after referral from specialists only, whereas in period 2 both specialists and general practitioners could refer patients for MR imaging. The direct cost (neuroradiologic methods and hospitalization) and indirect cost (sick-leave and estimated loss of production caused by the diagnostic procedure) were estimated. RESULTS AND CONCLUSION: In period 1, investigations were started in 75 patients (62 myelographies and 13 CT examinations); in period 2, in 227 patients (198 MR, 21 CT, and 8 myelographies). The estimated total cost increased from SEK 825,000 to 1,265,000 (53%), the cost per investigated patient decreasing from 11,000 to 5565 (50%), and the cost of preoperative investigation per operated patient decreasing from 8616 to 5563 (35%). The number of supplementary examinations was unchanged.
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5.
  • Cronqvist, Mats, et al. (författare)
  • Evaluation of time-of-flight and phase-contrast MRA sequences at 1.0 T for diagnosis of carotid artery disease. I. A phantom and volunteer study
  • 1996
  • Ingår i: Acta Radiologica. - 1600-0455. ; 37:3 Pt 1, s. 267-277
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE AND MATERIAL: The aim of this work was, firstly, to compare different manufacturer-provided MRA sequences in a 1.0 T MR unit, with respect to the visibility of an artificial stenosis in a flow phantom and, secondly, to evaluate the same sequences in healthy volunteers with respect to S/N ratio levels and practical in vivo implementation routines. METHODS: The studied sequences were 2D and 3D TOF and sequences with an acquisition time of approximately 10 min. Quantitative signal evaluation was made using single transverse partitions in all phantom experiments. MIP angiograms and MPR reconstructions were made for visual inspection of image quality. In vivo, the images were individually evaluated by visual inspection by experienced neuroradiologists. RESULTS: In the evaluation of the grade and length of a stenosis, a combination of MIP and MPR was seen to be the optimal and necessary procedure. A shortening of TE played an important and significant role in the visualization of the poststenotic flow in the phantom using TOF MRA. However, the shortest TE values gave poor S/N ratio in vivo. The good results achieved in the phantom studies for 3D phase-contrast were somewhat reversed in the volunteer studies, whereas 3D TOF sequences showed good results in both the phantom and the volunteer studies.
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6.
  • Ekholm, S, et al. (författare)
  • Tolerance and efficacy of Omniscan (gadodiamide injection) in MR imaging of the central nervous system
  • 1996
  • Ingår i: Acta Radiologica. - 1600-0455. ; 37:2, s. 223-228
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: This Swedish multicenter trial was performed on patients with known or suspected lesions of the CNS for which an MR examination using a contrast medium was indicated. A total of 8 MR centers participated in the study to establish the safety and efficacy of Omniscan (gadodiamide injection) in clinical routine using a standard dose of 0.1 mmol Gd/kg b.w. MATERIAL AND METHODS: Seven hundred adult patients who had been referred for MR investigation of suspected CNS lesions were included in the study. Since most patients were examined on an outpatient basis, it was decided to use an explicit questionnaire regarding adverse events that developed within 24 h after examination. The efficacy evaluation involved comparisons of detectability, delineation, and number of lesions before and after injection of Omniscan. RESULTS: No serious or unexpected adverse event was found. There were a total of 70 (10.2%) patients with adverse events, excluding those judged not to be contrast media-related. However, only 15 patients (2.2%) had adverse events that possibly or probably were related to the contrast medium. Usually, the symptoms were headache, dizziness, abnormal taste, and nausea. Two patients complained of itching, but only one developed urticaria. The efficacy was similar to that of other currently used Gd-based MR agents. Lesions were more often seen on T2-weighted images, but the contrast medium improved lesion delineation, contributing to higher certainty in diagnosis, and provided more confidence in excluding suspected abnormality. CONCLUSION: Omniscan was found to be a safe and clinically valuable contrast medium for MR imaging of the CNS.
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7.
  • Holtås, Stig, et al. (författare)
  • Spontaneous spinal epidural hematoma: findings at MR imaging and clinical correlation
  • 1996
  • Ingår i: Radiology. - 1527-1315. ; 199:2, s. 409-413
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To evaluate radiologic findings and clinical data in patients with spontaneous spinal epidural hematoma (SSEH). MATERIALS AND METHODS: Thirteen patients (10 men aged 28-71 years; three women aged 40-65 years) with SSEH from 1986 to 1995 underwent magnetic resonance (MR) imaging; six also underwent spinal angiography. Patients with minor trauma, anticoagulant therapy, increased bleeding tendency, or vascular lesions were included. RESULTS: The incidence was estimated to be 0.1 patients per 100,000 patients per year. On MR images, the hematoma was in the anterior (n=8) or posterior (n=4) epidural space or both (n=1). The most common location was the upper thoracic region. T1-weighted images were most useful owing to the pathognomonic signal shift from isointensity with the cord in the early period to hyperintensity in the intermediate stage. Five patients had minor trauma, and four were receiving anticoagulant therapy. CONCLUSION: A rough estimation of the incidence of SSEH is provided,and the results confirm the previously described association with minor trauma and anticoagulant therapy and low frequency of arteriovenous malformations.
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8.
  • Wallengren, Nils-Olof, et al. (författare)
  • Preoperative staging of rectal carcinoma using double-contrast MR imaging. Technical aspects and early clinical experiences
  • 1996
  • Ingår i: Acta Radiologica. - 1600-0455. ; 37:5, s. 791-798
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To improve preoperative staging of rectal carcinoma with MR imaging, using a double-contrast technique. MATERIAL AND METHODS: Imaging was performed in 12 patients before and after i.v. injection of Gd-DTPA and rectal administration of a superparamagnetic contrast medium, mainly containing magnetite. The diagnostic information was evaluated and compared with findings at surgery and histopathological analysis. RESULTS: The superparamagnetic contrast medium enema caused a distension of the rectum and intraluminal signal void, whereas Gd-DTPA enhanced the mucosa in T1-weighted images. This allowed an evaluation of the normal rectal wall and separation of the mucosa, tunica muscularis and perirectal space in all cases, which was not possible in T1- or T2-weighted precontrast images. The rectal carcinoma could be delineated and tumor invasion to the rectal wall determined in all cases. The findings in postcontrast MR corresponded with the findings at histopathological examination in 11 of 12 patients. The histopathological examination in one patient revealed metastases (< 1 cm) in regional lymph nodes, too small to be identified in pre- or postcontrast MR images. CONCLUSION: Double-contrast-enhanced MR imaging allows evaluation of the normal rectal wall and preoperative staging of rectal carcinoma.
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  • Resultat 1-8 av 8

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