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排序方式: 共有2240条查询结果,搜索用时 15 毫秒
1.
Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography 总被引:2,自引:0,他引:2
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study. 相似文献
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3.
Maxillary sinusitis in adults: an evaluation of placebo-controlled double-blind trials 总被引:1,自引:0,他引:1
BACKGROUND: In general practice, acute sinusitis is frequently diagnosed
and treated with antibiotics. OBJECTIVE: This study aimed to determine the
evidence for the effectiveness of antibiotic treatment in acute maxillary
sinusitis in adults by assessing the methodological quality of
placebo-controlled double-blind randomized trials. METHOD: An evaluation by
four raters through a 35-item scoring-scale for internal and external
validity of all placebo-controlled double-blind randomized trials on acute
sinusitis found between January 1966 and July 1996. RESULTS: Eighty-five
trials were excluded because they were not placebo-controlled,
double-blind, randomized, or were carried out in patients with chronic
sinusitis or in children. The three remaining trials were performed in
different populations (one in general practice) between 1973 and 1978. Only
one study claimed superiority of antibiotic treatment. Different inclusion
criteria and major outcome measures were used by the authors. The
reliability of major outcome events was reported poorly or not at all and
in two studies outcome measures were clinically inappropriate. The studies
scored 30-62% of the maximum attainable score for internal validity and
10-20% for external validity. CONCLUSION: The effectiveness of antibiotic
treatment in acute maxillary sinusitis in a general practice population is
not based sufficiently on evidence.
相似文献
4.
H Angus-Leppan GA Lambert J Michalicek 《Cephalalgia : an international journal of headache》1997,17(6):625-630
Co-existence of facial and occipital pain may occur in occipital neuralgia, migraine and cluster headache; suggesting convergence of trigeminal and cervical afferents. Such convergence has been shown in humans and other animals, but the site and extent of this are uncertain. In anaesthetized adult cats, the superior sagittal sinus and occipital nerve were stimulated electrically, and extracellular recordings made in the dorsolateral area of the upper cervical cord using glass-coated tungsten electrodes. Of 49 units in 10 cats, 33 (67%) had input from the superior sagittal sinus and the occipital nerve. Thirteen (27%) had superior sagittal sinus input and 3 (6%) had occipital nerve input. Convergent receptive fields were identified mechanically in 7 units. These experiments in cats show convergent input from occipital nerve and superior sagittal sinus on dorsolateral area units in two-thirds of cases studied. This experimental site of trigeminocervical convergence may relate to referral of pain in occipital neuralgia and other headaches. 相似文献
5.
In patients with PG-dependent renal function, NSAID administration
constantly reduces GFR and RBF in a dose-dependent fashion. In this
situation, the risk of overt acute renal failure is high and should be
taken into proper account. In contrast, the incidence of NSAID-related
renal structural alterations appears to be very low, yet the absolute
number of patients may be significant considering the wide use of such
drugs. Concerning the antiproteinuric effect of NSAIDs, the unfavourable
ratio risk/benefit does not seem to support their indication in proteinuric
nephropathies. The development of PGHS-2 selective inhibitors is promising,
and may open new therapeutical strategies in the treatment of the
progression of renal disease.
相似文献
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7.
R Glousman C Shields R Kerlan F Jobe S Lombardo L Yocum J Tibone R Gambardella 《The American journal of sports medicine》1988,16(4):321-326
Reconstruction for symptomatic anterior cruciate deficient knees has yielded varying success rates. Prosthetic cruciate replacement has recently become a potentially attractive alternative. The results of the Gore-Tex polytetrafluoroethylene ligament, which is intended as a permanent replacement, are reported. Eighty-two patients were followed prospectively, mean age was 28 years (range, 16 to 51 years) and mean followup was 18 months (range, 12 to 30 months). Subjective scores improved in all categories, including pain, swelling, giving way, locking, and stair climbing. All patients without complications had no episodes of actual giving way, considered themselves improved, and returned to activities of daily living at 3 weeks and athletics at 8 months. Range of motion lacking at 3 months was 2 degrees of extension and 10 degrees of flexion, and at 12 months was 0 degrees of extension and 4 degrees of flexion. All mean objective data, including the anterior drawer, Lachman, and pivot shift, demonstrated improvement at final followup. Cybex testing revealed improvement in relative quadriceps strength from 88% to 99%. The KT-1000 Arthrometer showed improvement in the injured-normal knee difference score throughout the follow-up period. Of importance is that while final objective data was improved over initial data, an early nonprogressive shift toward loosening was indicated by worsening of the drawer, Lachman, pivot shift, and KT-1000 scores. This shift may be attributed to resorption of interposed soft tissue, creep, or loosening of the graft. Subjective scores remained stable after improving. Complications included four ruptures, four chronic sterile effusions with partial attenuation, one infection, and one symptomatic loose body.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
Cystic meningiomas. Report of seven cases 总被引:1,自引:0,他引:1
Seven patients with cystic meningioma are reported. The computerized tomography appearance of these meningiomas may mimic that of a glial or metastatic tumor with cystic or necrotic changes, and lead to an incorrect presumptive diagnosis. Radiological evaluation and recognition are important for the surgical removal of these potentially curable neoplasms. 相似文献
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