AJNR. American journal of neuroradiology
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AJNR Am J Neuroradiol · Nov 2000
Comparative StudyA comparison of magnetization transfer ratio, magnetization transfer rate, and the native relaxation time of water protons related to relapsing-remitting multiple sclerosis.
Magnetization transfer (MT) imaging and measurements of the magnetization transfer ratio (MTR) have extended our capability to depict and characterize pathologic changes associated with multiple sclerosis (MS). We wanted to investigate whether the analysis of other MT parameters, such as magnetization transfer rate (k(for)) and relative measure of water content (T1(free)), adds insight into MS-related tissue changes. ⋯ Estimates of k(for) and T1(free) appear to complement MTR measurements for the understanding of MT changes that occur with different types of MS abnormalities in the brain.
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AJNR Am J Neuroradiol · Nov 2000
Letter Case ReportsAnaphylaxis after steroid and local anesthetic injections.
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AJNR Am J Neuroradiol · Oct 2000
Case Reports Comparative StudyThe role of MR angiography in the pretreatment assessment of intracranial aneurysms: a comparative study.
With developments in coil technology, intracranial aneurysms are being treated increasingly by the endovascular route. Endovascular treatment of aneurysms requires an accurate depiction of the aneurysm neck and its relation to parent and branch vessels preoperatively. Our goal was to estimate the clinical efficacy of MR angiography (MRA) in the pretreatment assessment of ruptured and unruptured intracranial aneurysms. We compared MRA source data (axial acquired partitions), multiplanar reconstruction (MPR) of these data, as well as maximum intensity projection (MIP) and 3D-isosurface images with intraarterial digital subtraction angiography (IA-DSA). ⋯ MRA is currently inferior to IA-DSA in pretreatment assessment of intracranial aneurysms, and can miss small lesions (<3 mm). It can, however, provide complementary information to IA-DSA, particularly in anatomically complex areas or in the presence of intramural thrombus. If MRA is used in aneurysm assessment, a meticulous technique with reference to both axial source data and MPR is mandatory. The axial source data should not be interpreted in isolation. Three-dimensional isosurface images are comparable to those of IA-DSA and are more reliable than are MIP images, which should be interpreted with caution.
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AJNR Am J Neuroradiol · Sep 2000
Functional MR imaging analysis of pain-related brain activation after acute mechanical stimulation.
Most studies concerning imaging of pain processing have used thermal, chemical, or electrical nociceptive stimulation. The aim of the present study was to determine the cortical representation of mechanical pain. For this, using functional MR (fMR) imaging at 1.5 T, we compared activation patterns during painful and nonpainful tonic mechanical stimulation in healthy volunteers. ⋯ The interindividual variability found in this fMR imaging study calls for repetitive single-subject analysis or more extensive studies of large groups of patients. Either may be based on fMR imaging analysis of brain activation after tonic mechanically induced pain, which leads to deep pain sensation similar to patients' painful sensations most commonly encountered in clinical practice.