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991.
992.
Edwin van der Linden Herman M. Kroon Joost Doornbos J. Hermans Johan L. Bloem 《Skeletal radiology》1998,27(6):297-305
Objective. To identify an optimal pulse sequence for in vitro imaging of hyaline cartilage at 0.5 T. Materials and methods. Twelve holes of varying diameter and depth were drilled in cartilage of two pig knees. These were submerged in saline and
scanned with a 0.5-T MR system. Sixteen T1-weighted gradient echo (GE), two T2-weighted GE, and 16 fast spin echo sequences
were used, by varying repetition time (TR), echo time (TE), flip angle (FA), echo train length, profile order, and by use
of fat saturation. Contrast-to-noise ratios (CNR) of cartilage versus saline solution and cartilage versus subchondral bone
were measured. Cartilaginous lesions were evaluated separately by three independent observers. Interobserver variability and
correlation between the quantitative and qualitative analyses were calculated. Results. The mean CNRs of two specimens of cartilage versus saline solution ranged from 6.3 (±2.1) to 27.7 (±2.5), and those of cartilage
versus subchondral bone from 0.3 (±0.2) to 22.5 (±1.4). The highest CNR was obtained with a T1-weighted spoiled 3D-GE technique
(TR 65 ms, TE 11.5 ms, FA 45°). The number of lesions observed per sequence varied from 35 to 69. Observer agreement was fair
to good. The T1-weighted spoiled GE sequences with a TR of 65 ms, TE of 11.5 ms and FA of 30° and 45° were significantly superior
to the other 34 sequences in the qualitative analysis. Conclusion. T1-weighted spoiled 3D-GE sequences with a TR of 65 ms, a TE of 11.5 ms, and a FA of 30–45° were found to be optimal for
in vitro imaging of cartilage at 0.5 T. 相似文献
993.
Diagnostic imaging is pivotal in the initial detection, characterization, staging and post-treatment follow-up of patients
with high-grade osteogenic and Ewing’s sarcoma. In the present review article, conventional and new imaging modalities are
discussed with regard to the monitoring of the effect of neoadjuvant chemotherapy in such patients. Presurgical monitoring
of response to chemotherapy may have an impact on modification of neoadjuvant treatment protocols, on patient selection for
the performance and timing of limb-salvage surgery and on planning of radiation therapy (in non-operated Ewing’s sarcomas)
and selection of postoperative chemotherapy regimens. Dynamic contrast-enhanced MR imaging, as part of a routine MR protocol,
assists in the detection of the most viable parts of the tumour and serves as an initial standard for follow-up of the metabolic
activity of the tumour during and after chemotherapy, both in small intraosseous tumours and in tumours with an associated
soft tissue mass. In combination with selected morphological features, dynamic imaging parameters are therefore advocated
for monitoring the effect of neoadjuvant chemotherapy in patients with osteogenic and Ewing’s sarcoma. 相似文献
994.
van Iersel MB Hoefsloot W Munneke M Bloem BR Olde Rikkert MG 《Zeitschrift für Gerontologie und Geriatrie》2004,37(1):27-32
INTRODUCTION: Diminished mobility often accompanies dementia and has a great impact on independence and quality of life. New treatment strategies for dementia are emerging, but the effects on gait remains to be studied objectively. In this review we address the general effects of dementia on gait as revealed by quantitative gait analysis. METHODS: A systematic literature search with the (MESH) terms: 'dementia' and 'gait disorders' in Medline, CC, Psychlit and CinaHL between 1980-2002. Main inclusion criteria: controlled studies; patients with dementia; quantitative gait data. RESULTS: Seven publications met the inclusion criteria. All compared gait in Alzheimer's Disease (AD) with healthy elderly controls; one also assessed gait in Vascular Dementia (VaD). The methodology used was inconsistent and often had many shortcomings. However, there were several consistent findings: walking velocity decreased in dementia compared to healthy controls and decreased further with progressing severity of dementia. VaD was associated with a significant decrease in walking velocity compared to AD subjects. Dementia was associated with a shortened step length, an increased double support time and step to step variability. DISCUSSION: Gait in dementia is hardly analyzed in a well-designed manner. Despite this, the literature suggests that quantitative gait analysis can be sufficiently reliable and responsive to measure decline in walking velocity between subjects with and without dementia. More research is required to assess, both on an individual and a group level, how the minimal clinically relevant changes in gait in elderly demented patients should be defined and what would be the most responsive method to measure these changes. 相似文献
995.
Carpenter MG Allum JH Honegger F Adkin AL Bloem BR 《Journal of neurology, neurosurgery, and psychiatry》2004,75(9):1245-1254
OBJECTIVE: We investigated trunk control, protective arm movements, and electromyographic responses to multidirectional support-surface rotations in patients with Parkinson's disease (PD), aiming to better understand the pathophysiology underlying postural instability in PD, on and off antiparkinson medication. METHODS: Ten patients with PD were compared with 11 age matched healthy controls. Seven patients were also tested without (OFF) antiparkinson medication. All subjects received rotational perturbations (7.5 deg amplitude) that were randomly delivered in six different directions. RESULTS: The PD patients had decreased trunk rotation and ankle torque changes, consistent with a stiffening response. Stiffness appeared to be caused by the combined action of three factors: co-contraction that interfered in particular with the normal response asymmetry in trunk muscles; increased response amplitudes in agonist and antagonist muscles at both medium (approximately 80 ms) and balance correcting (approximately 120 ms) response latencies; and increased background activity in lower leg, hip, and trunk muscles. Although the patients had significantly earlier onset of deltoid muscle responses, this gave no functional protection because the arm movements were abnormally directed. Most instability in PD occurred for backward falls, with or without a roll component. Medication provided partial improvement in arm responses and trunk roll instability. CONCLUSIONS: Our results confirm previous findings in ankle muscles, and provide new information on balance impairments in hip, trunk, and arm responses in PD. 相似文献
996.
Magnetic resonance imaging of knee cartilage using a water selective balanced steady-state free precession sequence 总被引:1,自引:0,他引:1
Kornaat PR Doornbos J van der Molen AJ Kloppenburg M Nelissen RG Hogendoorn PC Bloem JL 《Journal of magnetic resonance imaging : JMRI》2004,20(5):850-856
PURPOSE: To compare an optimized water selective balanced steady-state free precession sequence (WS-bSSFP) with conventional magnetic resonance (MR) sequences in imaging cartilage of osteoarthritic knees. MATERIALS AND METHODS: Flip angles of sagittal and axial WS-bSSFP sequences were optimized in three volunteers. Subsequently, the knees of 10 patients with generalized osteoarthritis were imaged using sagittal and axial WS-bSSFP and conventional MR imaging techniques. We calculated contrast-to-noise ratios (CNR) between cartilage and its surrounding tissues to quantitatively analyze the various sequences. Using dedicated software we compared, in two other patients, the accuracy of cartilage volume measurements with anatomic sections of the tibial plateau. RESULTS: CNRtotal eff (CNR efficiency between cartilage and its surrounding tissue) using WS-bSSFP was maximal with a 20-25 degrees flip angle. CNRtotal eff was higher in WS-bSSFP than in conventional images: 6.1 times higher compared to T1-weighted gradient echo (GE) images, 5.1 compared to proton-density (PD) fast spin echo (FSE) images, and 4.8 compared to T2-weighted FSE images. The mean difference of cartilage volume measurement on WS-bSSFP and anatomic sections was 0.06 mL compared to 0.24 mL for T1-GE and anatomic sections. CONCLUSION: A WS-bSSFP sequence is superior to conventional MR imaging sequences in imaging cartilage of the knee in patients with osteoarthritis. 相似文献
997.
Pseudoaneurysms complicating pancreatitis: detection by CT 总被引:3,自引:0,他引:3
Burke JW; Erickson SJ; Kellum CD; Tegtmeyer CJ; Williamson BR; Hansen MF 《Radiology》1986,161(2):447-450
Complications of pancreatitis such as pseudocyst formation and abscess are well known to radiologists. Secondary formation of pseudoaneurysms has not been emphasized in the radiologic literature. The great morbidity and mortality associated with pseudoaneurysms emphasize the importance of early detection. Three patients are described whose angiographically proved pseudoaneurysms were demonstrated on contrast material-enhanced abdominal CT scans obtained for evaluation of pancreatitis. A homogeneously enhancing structure within or adjacent to a pancreatic pseudocyst or contiguous with a vascular structure should be considered highly suspicious for an associated pseudoaneurysm. 相似文献
998.
Wood GS; Hardman DL; Boni R; Dummer R; Kim YH; Smoller BR; Takeshita M; Kikuchi M; Burg G 《Blood》1996,88(5):1765-1770
999.
Vitronectin expression in rheumatoid arthritic synovia--inhibition of plasmin generation by vitronectin produced in vitro 总被引:1,自引:0,他引:1
The plasmin-generating system controls, to a great extent, the degree of
connective tissue destruction as well as fibrin deposition two contributors
to the pathogenesis generated in diseases such as rheumatoid arthritis.
Vitronectin, an adhesive blood glycoprotein, has the potential to modulate
this system by its known capacity to interact with plasminogen activator
inhibitor-1, plasminogen activators, the urokinase plasminogen activator
receptor, and plasminogen. The net effect of these interactions, in terms
of plasmin generation, is not known as yet. In the present study, we have
investigated the possible expression and role of vitronectin in rheumatoid
arthritic synovia. Analysis of synovial frozen sections by
immunofluorescence showed the presence of vitronectin in the 13 cases
studied. In situ hybridization analysis demonstrated the presence of
vitronectin mRNA in cells present in areas rich in infiltrating
inflammatory cells. The adherent population of the rheumatoid arthritic
synovial cells was isolated and found to synthesize and secrete vitronectin
into the medium (seven of 10 isolates), as assessed by metabolic labelling
and immunoprecipitation. Plasmin-generating activity was detected in the
adherent synovial cells, and this activity was increased by antibodies to
vitronectin. Our findings show, for the first time, that vitronectin can be
endogenously produced in a pathophysiological system where it can inhibit
the generation of plasmin.
相似文献
1000.
de Hoon EW Allum JH Carpenter MG Salis C Bloem BR Conzelmann M Bischoff HA 《Archives of physical medicine and rehabilitation》2003,84(6):838-842
OBJECTIVE: To examine whether trunk sway and walking speed differ between elderly "stoppers" and "nonstoppers" during a shorter version of the stops walking while talking (SWWT) test-an observational assessment of impaired dual-task performance-and during a normal walking trial. DESIGN: The original SWWT test was administered on the way to the test room (over a distance of 150m). Then, subjects were asked to walk 2 trials of 8m while wearing a trunk sway measuring device strapped firmly to their lower back. For the first 8-m trial, no questions were asked (control trial). During the second 8-m trial, subjects were asked an easy question (What is your age?) after walking 2m. SETTING: Long-stay geriatric care unit in Switzerland. PARTICIPANTS: Seventeen institutionalized elderly (16 women, 1 man; mean age, 86.3y; range, 79-93y). Subjects had to be able to walk at least 150m and to understand simple questions. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The amplitude of trunk sway angle and angular velocity in the forward-backward (pitch) and side-to-side (roll) directions and the duration of each trial were compared between the two 8-m walking trials with and without a question among subjects who did and did not come to a complete stop. RESULTS: In the original SWWT test, 4 persons stopped walking while talking, compared with 8 persons who stopped in the short (8-m) walking trial when a question was asked. Persons who stopped during the 8-m trial when a question was asked had significantly longer walking durations (by 19s) and larger trunk roll angular displacements (by 5.5 degrees ) during trials, both with and without a question. For both stoppers and nonstoppers, duration was longer during the trial when a question was asked. CONCLUSION: A fixed and brief walking distance, coupled with a single sudden question, provided an effective method of identifying subjects who stop walking while talking. These subjects are those who have slower walking speeds and more unstable trunk control in the roll plane even under normal walking conditions. Our findings support the predictive capabilities of a brief SWWT test for the unstable and fall-prone elderly, as well as the usefulness of objective trunk sway measures to identify gait instabilities. 相似文献