1,720,973 research outputs found
NON INVASIVE DIAGNOSIS WITH ORBITAL COLOR DOPPLER (OCD) OF CAROTID CAVERNOUS SINUS FISTULAS (CCSF): PERSONAL EXPERIENCE IN 20 CASES
No full textFollow-up of coiled cerebral aneurysms at 3T: comparison of 3D Time of flight MR angiography and contrast-enhanced MR angiography
No full textFollow-up of coil.cerebr.aneurysms:compar.of 3-dimens.time-of-flight magn.reson.angiogr.at3tesla with 3-dimens. time-of-flight magn.reson.angiogr.and contrast-enhanced magn.reson.angiogr. at 1.5 tesla
No full textOBJECTIVES: To compare three-dimensional (3D) time-of-flight (TOF)-magnetic resonance angiography (MRA) at 3 T with 3D TOF-MRA and ultrafast contrast-enhanced (CE)-MRA at 1.5 T and to determine the optimum MRA sequence for follow-up of cerebral aneurysms treated with Guglielmi detachable coils (GDCs). MATERIAL AND METHODS: Twenty-eight patients treated with GDCs for 29 cerebral aneurysms underwent MRA at 3 T and 1.5 T within 24 hours (during the same session for outpatients). All imaging was performed using a sensitivity-encoding head coil (SENSE factor = 2). Unenhanced axial 3D TOF-MRA at 3 T was performed with repetition time (TR)/echo time (TE) = 16/2.9. At 1.5 T, axial 3D TOF-MRA (TR/TE = 23/4) was performed first, followed by axial 3D ultrafast gradient echo MRA (TR/TE = 6/2) enhanced with 0.1 mmol/kg gadobenate dimeglumine (MultiHance). Source images and maximum intensity projection and shaded surface display reconstructions for each acquisition sequence were evaluated for quality of visualization of residual aneurysm patency and scored for visualization preference. RESULTS: Residual aneurysm was detected in 15/29 cases on CE-MRA at 1.5 T and TOF-MRA at 3 T but in only 11/29 cases on TOF-MRA at 1.5 T. CE-MRA at 1.5 T was preferred to TOF-MRA at 1.5 T in 13 cases (P = 0.004) and to TOF-MRA at 3 T in 3 cases. TOF-MRA at 3 T was preferred to TOF-MRA at 1.5 T in 11 cases (P = 0.04) but was not preferred to CE-MRA at 1.5 T in any case. The parent artery was identifiable in all 29 cases after TOF-MRA at 3 T and CE-MRA at 1.5 T but in only 27 cases after 3D TOF-MRA at 1.5 T. CONCLUSIONS: TOF-MRA follow-up of coiled aneurysms is better at 3 T than at 1.5 T; nevertheless, greater definition of residual patency is achieved with ultrafast CE-MRA at 1.5 T
Debunking 7 myths that hamper the realization of randomized controlled trials on intra-arterial thrombolysis for acute ischemic stroke.
No full textBackground and Purpose—Although intravenous (IV) thrombolysis is the standard treatment for patients with ischemic
stroke occurring within 3 hours from symptom onset, a few interventional neuroradiologists have been treating this
category of patients by an intra-arterial (IA) route for 25 years. However, evidence is still required to support the
clinical feeling that IA treatment, which needs longer time and greater complexity, leads to a better outcome. Therefore,
the objective of the present review was to analyze beliefs and myths underlying the selection of patients for IA
thrombolysis.
Methods and Results—We identified and debunked the following myths on IA thrombolysis: (1) IA thrombolysis works
better than IV because it achieves higher recanalization rates; (2) IA thrombolysis works better than IV after the 3-hour
window; (3) IA thrombolysis works better than IV in vertebrobasilar stroke; (4) carotid duplex, transcranial doppler, CT
angiography, or MRA should be used to screen for major vessel occlusion treatable with IA thrombolysis; (5) to be
treated with IA thrombolysis, patients should be selected with diffusion/perfusion MRI; (6) IA thrombolysis should be
used as a “rescue” therapy for IV thrombolysis; and (7) the efficacy of IA thrombolysis depends on the thrombolytic
agent or the device used.
Conclusion—Evidence on acute stroke management with IA thrombolysis is scant. Therefore, neither clinicians nor
patients have enough information to make truly informed decisions about the most appropriate treatment. Only
randomized controlled trials can clear uncertainties about the possible superiority of IA over IV thrombolysis.
Regretfully, case series on IA treatment have limited the organization of such trials and have only favored the spread
of myths
Evaluation of prognostic factors as predictor of AVMS obliteration after Gamma Knife Radiosurgery
No full text"Background: The reported AVMs obliteration rate after Gamma Knife radiosurgery (GKS) ranges from 70 to 94 %. The objective of the present study was to assess prognostic factors predictive for cerebral AVMs obliteration in 127 patients who underwent GKS. Methods: The AVMs were classified according to the Spetzler-Martin classification. Twenty-one cases (16.5 %) were classified as grade I, 46 cases (36.2 %) as grade II, 51 cases (40.1 %) as grade III, and nine cases (7.1 %) as grade IV-V. The AVMs were deeply located in 16.5 % of patients. The peripheral prescription dose ranged from 16 to 30 Gy (mean 22.3 Gy). The AVMs volume ranged from 0.1 to 13 cc (mean 2.7 cc). Results: In 72 patients out of the 104 (69.2 %) with a radiological follow-up, MRI showed the AVM obliteration; in 54 cases (60 %) out of the 90 that performed a DSA, a complete AVM obliteration was achieved (average closure time 48.5 months). The volume of the nidus (p = 0.001), the prescription dose (p = 0.004), the 2002 Pollock-Flickinger classification (p = 0.031), and their 2008 revised classification (p = 0.025) were found to be statistically significant in predicting the probability of AVM closure. In the multivariate analysis, only the prescription dose was found to be an independent prognostic factor (p = 0.009) for AVM obliteration. Conclusions: The volume of the nidus and the prescription dose significantly influence the outcome of radiosurgical treatment. The Pollock-Flickinger classification was found to be a reliable scoring system in predicting the AVM closure and an important tool for selection of patients candidate for GKS. © 2013 Springer-Verlag Wien.
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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