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  • 1
    ISSN: 1432-1459
    Keywords: Key words Multi-parametric ; Multiple sclerosis ; Magnetic ; resonance imaging ; Lesion volume ; Clinico-radiological correlation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Magnetic resonance imaging (MRI) is frequently used to monitor new treatments in multiple sclerosis (MS), but its role is limited by the uncertain relationship between MRI parameters and clinical disability. A brain MRI study using nine MRI parameters was undertaken in 15 MS patients with a wide spectrum of disability to evaluate the relationship between each parameter and disability. A strong correlation was found between disability (measured using Kurtzke’s EDSS) and total lesion load on both proton density (PD; r = 0.79) and T1 (r = 0.71) weighted sequences. There was also a strong correlation of disability with average lesion magnetisation transfer ratio (MTR; r = –0.74) and calculated T1 (r = 0.71) but not with calculated T2 or the average signal intensity of lesions on the conventional T1-weighted, PD-weighted and heavily T2-weighted images. Thus, four parameters which measured either the extent of lesions (PD lesion load) or their pathological severity (MTR, calculated T1, hypointense T1-lesion load) were correlated significantly with disability. While this suggests that such parameters will be useful in treatment trial monitoring, further multi-parameter MRI studies, of larger cohorts and using a wider range of techniques, are indicated.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1459
    Keywords: Quantitative MRI ; Disability ; Multiple sclerosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In a preliminary study, we compared by means of quantitative magnetic resonance imaging (MRI) methods (1) the T2 values and the decay characteristics of chronic brain lesions, (2) the T2 values of normal-appearing frontal white matter (NAWM) and (3) brain lesion volumes in patients with benign and secondary progressive multiple sclerosis (MS) in order to evaluate the mechanisms underlying the development of disability. Eleven clinically definite MS patients with either benign MS (n = 5) or secondary progressive MS (n = 6) were studied. Fifty-two chronic lesions (identified by comparison with MRI scans obtained at least 12 months previously) were identified. The mean T2 of large lesions (cross-sectional area greater than 41 mm2) and of the NAWM was similar in both clinical groups. However, small lesions had higher mean T2 values (P 〈 0.01) in the benign group, probably at least in part because of partial volume effects. Analysis of large lesions revealed biexponential T2 relaxation in 6 of 8 “secondary progressive” and in 2 of 16 “benign” lesions, perhaps indicating a greater degree of axonal loss in large lesions of patients with secondary progressive MS. Patients with secondary progressive MS had higher (although not significant) total and infratentorial lesion loads than those of the benign group. These preliminary findings suggest, but do not establish, that variations in the extent, site and pathological nature of lesions may all contribute to different patterns of disease evolution in MS.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1459
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1920
    Keywords: Magnetic resonance imaging ; Arteriovenous malformations ; Spinal cord ; Contrast media
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Arteriovenous fistulae and malformations (AVFs and AVMs) of the spinal cord are rare, potentially treatable causes of progressive disability. Although a variety of MRI abnormalities has been described, the diagnosis rests on the findings on selective spinal angiography.Collecting T2*-weighted MR images during the passage of a gadolinium bolus gives information about perfusion and blood volume. We carried out dynamic MRI in seven patients with vascular abnormalities (5 dural AVFs, 1 intramedullary AVM, 1 cryptic angioma) and in two patients without an AVM. High resolution T1- and T2-weighted sagittal images of the whole spinal cord were first obtained using a multiarray receiver coil. Sagittal radiofrequency spoilt gradient echo images (GE34/25, flip angle 100) were then obtained during bolus injection of gadolinium-DTPA. Abnormalities were seen in all seven patients with AVFs or AVMs. In the patient with an intramedullary AVM and four of the five with dural AVFs transient signal reduction was seen within the perimedullary venous plexus during passage of the bolus. The findings correlated well with those from selective spinal angiography. We conclude that dynamic MRI offers a useful adjunct to angiography and may localise an arteriovenous shunt when conventional MRI fails to do so. In combination with high-resolution imaging of the entire spinal cord the technique may make myelography redundant; it is simple, well tolerated and can be carried out without significant time penalty.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1920
    Keywords: Magnetic resonance imaging ; Fast spin-echo ; Multiple sclerosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Long repetition time (TR) spin-echo (SE) with T2- or proton density weighting is the sequence of choice to detect the brain lesions of multiple sclerosis (MS). Fast spin-echo (FSE) permits the generation of T2-weighted images with similar contrast to SE but in a fraction of the time. We compared the sensitivity of FSE and SE in the detection of the brain lesions of MS. Six patients with clinically definite MS underwent brain imaging with both dual echo (long TR, long and short echo time (TE) SE and dual echo FSE. The SE and FSE images were first reviewed independently and then compared. A total of 404 lesions was detected on SE and 398 on FSE. Slightly more periventricular lesions were detected using SE than FSE (145 vs 127), whereas more posterior cranial fossa lesions were detected by FSE (77 vs 57). With both SE and FSE the short TE images revealed more lesions than the long echo. These results suggest that FSE could replace SE as the long TR sequence of choice in the investigation of MS.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1920
    Keywords: Key words Magnetisation transfer ratio ; Cervical spinal cord ; Multiple sclerosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract MRI readily detects the lesions of multiple sclerosis (MS) in the brain and spinal cord. Conventional MRI sequences do not, however, permit distinction between the various pathological characteristics (oedema, demyelination, axonal loss and gliosis) of lesions in MS. Magnetisation transfer (MT) imaging may be more specific in distinguishing the pathologies responsible for disability in MS, namely demyelination and axonal loss, and therefore may have a potential role in monitoring treatment. We have applied MT imaging to the cervical spinal cord to see if it is feasible to measure MT ratios (MTR) in this region where pathological changes may result in considerable disability. We studied 12 patients with MS and 12 age- and sex-matched normal controls using a sagittal T2-weighted fast spin-echo sequence with and without an MT pulse. The median value for cervical cord mean MTR measurement in normal controls was 19.30 % units (interquartile range 19.05–19.55), whereas values were significantly lower in MS patients (median = 17.95 % units, interquartile range 17.25–19.00, P = 0.0004). There was a low intrarater variability for repeated mean MTR measurements. We conclude that it is possible to measure MTR in the cervical spinal cord, that a significant reduction occurs in patients with MS, and that there may be a role for this measure in future MS treatment trials.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1920
    Keywords: Key words Magnetic resonance spectroscopy ; Spinal cord ; Multiple sclerosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Magnetic resonance spectroscopy (MRS) has been used in a variety of conditions affecting the central nervous system. Until now, only the brain has been studied, and spectroscopy of the spinal cord has not been previously reported. During the past 12 months, we have been experimenting with MRS of the cervical spinal cord of healthy volunteers. We present this technique, its current limitations, and possible future technological improvements and potential applications.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-1920
    Keywords: Key words Multiple sclerosis ; Magnetic resonance imaging ; Pulse sequences ; Echo-planar imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We used five MRI sequences in six patients with multiple sclerosis (MS): conventional spin-echo (CSE) with 5-mm slices; 2D fast spin-echo (FSE) with 2-mm slices; multishot T2*-weighted echo-planar imaging (EPI) with 5-mm slices; fast fluid-attenuated inversion recovery (fFLAIR) with 2-mm slices; and 3D fast spin-echo with 1.5-mm-thick slices. A total of 225 lesions were detected on CSE, 274 on 2D FSE, 137 on EPI, 385 on fFLAIR and 320 on 3D FSE. The EPI sequence was clearly the least sensitive and susceptibility artefact was a problem, particularly in the brain stem and temporal lobes. Fast FLAIR displayed a much higher number of supratentorial lesions (380) than 3D FSE (297), 2D FSE (264) or CSE (211). However, in the posterior cranial fossa 3D FSE was the most sensitive sequence (23 lesions), followed by CSE (14) and 2D FSE (10), while fFLAIR (5) was extremely insensitive.
    Type of Medium: Electronic Resource
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