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D G MacManus

Publications and source records attributed to D G MacManus.

71 records · Page 4Linked to original sources
PubMed1990

Breakdown of the blood-brain barrier precedes symptoms and other MRI signs of new lesions in multiple sclerosis. Pathogenetic and clinical implications.

From an extensive serial magnetic resonance imaging (MRI) study in multiple sclerosis (MS) we have identified 4 cases in which disruption of the blood-brain barrier, as detected by gadolinium-DTPA enhancement, preceded other MRI abnormalities and in 1 case clinical evidence of the new lesion. This supports the view that a defect in the blood-brain barrier, and therefore inflammation, is an early and possibly crucial event in the pathogenesis of the new lesion in MS. These cases showed a marked discrepancy between MRI abnormality and symptoms. The mechanisms contributing to this disparity are discussed, and it is concluded that far from being surprising it is to be expected.

Adult↗
PubMed1990

Magnetic resonance imaging of inflammatory and demyelinating white-matter diseases of childhood.

Magnetic resonance imaging (MRI) was performed on 36 children and two adults (with clinical presentation during childhood) with white-matter disease of the central nervous system. Abnormalities were readily demonstrated in patients with multiple sclerosis, acute disseminated encephalomyelitis, leucodystrophies and subacute sclerosing panencephalitis: MRI demonstrated the extent and distribution of abnormalities more clearly than computed tomography for all these disorders. The abnormalities tended to be asymmetrical and multifocal in multiple sclerosis and acute disseminated encephalomyelitis, and more confluent and symmetrical in the leucodystrophies. Children with clinically isolated optic neuritis had a significantly lower frequency of MRI brain-lesions than adults with the same disorder. MRI should be regarded as the radiological investigation of choice when white-matter disease is suspected in children.

Adolescent↗
PubMed1990

Heterogeneity of blood-brain barrier changes in multiple sclerosis: an MRI study with gadolinium-DTPA enhancement.

We performed 15 dynamic gadolinium-DTPA (Gd-DTPA)-enhanced MRI studies in 8 patients with relapsing and remitting multiple sclerosis; 7 were follow-up studies. We measured the time course of enhancement in 102 enhancing lesions for up to 384 minutes, with rest breaks. Immediate postcontrast MRIs demonstrated many different patterns of enhancement. We observed both uniformly enhancing and ring enhancing lesions. The enhancing regions were often less extensive than the corresponding high signal on T2-weighted images. Three lesions were seen with Gd-DTPA but not on unenhanced scans; 1 was seen on unenhanced scans 10 days later, suggesting that blood-brain barrier disturbance may precede other MRI signs of MS lesions. Three months later, some high-signal areas on T2-weighted scans had decreased in size to resemble the areas previously outlined by Gd-DTPA. This technique provides useful information about the pathogenesis and behavior of MS lesions.

Adolescent↗
PubMed1989

Quantitative magnetic resonance imaging in multiple sclerosis: the effect of high dose intravenous methylprednisolone.

Magnetic resonance imaging was performed on 50 patients with clinically definite or probable multiple sclerosis before and 15 days after starting treatment with intravenous methylprednisolone (0.5 g daily for 5 days). Scans were abnormal in 49 patients. New lesions had appeared on the second scan in nine individuals and in seven a single pre-existing lesion appeared to have become smaller but in no case were lesions seen to disappear. Two patients showed both reduction in the size of an abnormal area and development of a single new lesion indicating that corticosteroids do not appear rapidly to alter the process underlying plaque formation. Measurements of relaxation times were performed in 12 randomly selected patients. All showed elevated values in normal appearing white matter but not cortex before treatment compared with 18 healthy controls. After treatment a significant decrease of T1 and T2 was observed in cortex, and of T1 alone in normal appearing white matter. No significant change could be detected within lesions, a finding attributed to the wide range of relaxation values observed at these sites before treatment. Since brain water content is increased in normal appearing white matter of multiple sclerosis patients, and is significantly reduced by high-dose methylprednisolone, resolution of oedema may contribute to the rapid spontaneous or corticosteroid induced symptomatic recovery that characterises the disease in its early stages.

Adult↗
PubMed1989

Magnetic resonance imaging in Leber's optic neuropathy.

Thirteen males with Leber's optic neuropathy had magnetic resonance imaging (MRI) of the brain, and in eight the optic nerves were imaged using STIR (Short Time Inversion Recovery) sequences. All optic nerve scans were abnormal. In seven with bilateral visual loss four showed bilateral increased optic nerve signal and three unilateral increase. The involvement was of the mid and posterior intra-orbital sections over three 5 mm slices or more with sparing of the anterior portion. One patient with unilateral visual loss had increased signal only on the affected side. Brain MRI was normal, in marked contrast to the findings in clinically isolated optic neuritis in which multiple white matter lesions are seen in the majority.

Adult↗
PubMed1988

Chronic unilateral optic neuropathy: a magnetic resonance study.

We studied the clinical, electrophysiological, and magnetic resonance imaging (MRI) features of 20 patients with chronic unilateral optic neuropathy (CUON): progressive unilateral visual failure lasting a minimum of 6 months. The patients, 10 male and 10 female, ranged in age from 12 to 77 years (mean 44) and had a mean duration of symptoms of 22 months. All had signs of optic nerve dysfunction. Each patient was studied with MRI using a short TI inversion recovery (STIR) sequence to delineate the optic nerve from surrounding orbital tissue. Three distinct groups of patients with CUON were identified using MRI. In the first group (8/20) the optic nerve was compressed by an extrinsic mass, whereas in the second group (5/20) CUON resulted from an intrinsic tumor of the optic nerve or sheath. In both groups STIR sequences compared favorably with computed tomography in identifying mass lesions. MRI was superior in delineating distortion of the optic nerve by mass or tumor extension beyond the orbit. In the third group (7/20) no mass was evident on MRI. However, STIR sequences revealed altered signal (long T1) in clinically symptomatic nerves. In 4 of the patients T2-weighted cerebral MRI disclosed periventricular lesions suggestive of disseminated white matter disease. We conclude that MRI complements clinical and electrophysiological testing in the assessment of CUON.

Adolescent↗
PubMed1988

The early risk of multiple sclerosis after optic neuritis.

Serial brain MRI was performed in 53 patients with clinically isolated optic neuritis. Using clinical and imaging evidence for relapse, multiple sclerosis developed within a mean of 12 months in 19 of 34 cases (56%) with brain lesions at presentation, and in only 3 of 19 cases (16%) without (Relative Risk = 6.8, p less than 0.005).

Adolescent↗
PubMed1988

Magnetic resonance imaging of the optic nerve in optic neuritis.

Magnetic resonance imaging (MRI) of the optic nerves using the STIR (short inversion time inversion recovery) sequence was performed in 37 adult patients with a recent or past attack of optic neuritis. MRI revealed high-signal regions in 84% of symptomatic and 20% of asymptomatic nerves. The mean longitudinal extent of lesions was 1 cm. Slow or poor visual recovery was associated with more extensive lesions, or lesions within the optic canal. Disk swelling was usually associated with anterior lesions but also occurred with lesions in the canal. Visual evoked potentials were even more sensitive than MRI in detecting lesions and are still the investigation of choice in suspected demyelinating disease involving the optic nerve.

Adult↗
PubMed1988

Magnetic resonance imaging in central nervous system sarcoidosis.

We performed brain MRIs on 21 patients with CNS sarcoidosis. Brain CTs were performed in 18 of these. Parenchymal lesions were seen in 17 of 21 with MRI, compared with 9 of 18 with CT. MRI detected a greater number of parenchymal lesions in cases where both CT and MRI were positive, and some lesions appeared more extensive with MRI than with CT. The most common MRI pattern was one of periventricular and multifocal white matter lesions (14 cases). Such a pattern is not specific, and other recognized causes for it were identified in four cases. It is likely, however, that sarcoid tissue causes this pattern in some cases, and confirmation was obtained from cerebral biopsy in one. In six patients, the white matter changes were indistinguishable from those seen in multiple sclerosis. Contrast-enhanced CT in two patients showed diffuse meningeal involvement not seen with MRI. MRI is the investigation of choice in detecting parenchymal changes in the brain of patients with CNS sarcoidosis and may prove useful in monitoring treatment in such cases.

Adolescent↗
PubMed1987

Magnetic resonance imaging in isolated noncompressive spinal cord syndromes.

The frequency with which patients presenting with acute or chronic noncompressive cord syndromes subsequently develop multiple sclerosis is uncertain. Magnetic resonance imaging (MRI) was performed on 121 patients with such syndromes to determine the frequency of asymptomatic brain lesions and to assess the sensitivity of MRI in detecting the local cord lesion. MRI findings were compared with those from visual, brainstem, and somatosensory evoked potentials (VEPs, BAEPs, SEPs), and cerebrospinal fluid electrophoresis. Lesions were seen in the appropriate cord region in 47 of 73 patients (64%) with a cervical syndrome, and in 7 of 25 patients (28%) with a thoracic or lumbar syndrome. MRI demonstrated more cervical lesions than did SEPs, but fewer thoracic or lumbar lesions. Cord swelling was seen in 6 patients and atrophy in 10. Of those with acute syndromes, abnormalities were seen with brain MRI in 18 of 32 patients (56%), with VEPs in 2 of 30 patients (7%), and with BAEPs in 2 of 24 patients (8%). In patients with chronic syndromes, abnormalities were seen with brain MRI in 73 of 89 patients (82%), with VEPs in 22 of 80 patients (28%), and with BAEPs in 12 of 62 patients (19%). Brain MRI was thus more sensitive than evoked potentials were in establishing multiplicity of lesions. However, in acute syndromes, it was not possible to diagnose multiple sclerosis from a single abnormal brain scan in chronic syndromes, a diagnosis of clinically probable multiple sclerosis could be made from one scan, provided there was no better explanation for the abnormalities: the added presence of oligoclonal bands allows a diagnosis of laboratory-supported, definite multiple sclerosis as was the case in 28 patients in this series.

Adolescent↗
PubMedDate not supplied

Macroscopic and microscopic assessments of disease burden by MRI in multiple sclerosis: relationship to clinical parameters.

We have evaluated macroscopic white matter abnormalities (visible lesions) together with microscopic abnormalities in the normal appearing white matter (NAWM) of patients with multiple sclerosis (MS) to determine their relative contributions to the development of disability. The total visible lesion volume (TLV) was computed as a measure macroscopic changes, whereas both texture analysis and T2 were used as possible indicators of diffuse disease in the NAWM. Dual echo T2-weighted SE images were obtained from 41 patients with definite MS: 10 primary progressive (PP), 11 secondary progressive (SP), 10 benign (BE), 10 early relapsing remitting (ERR), as well as from 10 healthy controls. Calculation of T2 and texture parameters were performed in a region of frontal NAWM of patients and controls. The TLV of each patient was measured using a semiautomated lesion detection program. No significant differences were found between the controls and the patients for all texture parameters examined. However, NAWM T2 was longer in the patients than in the controls (P = .02). Mean TLV was highest for SP and lowest for BE and ERR patients. A significant correlation was found between TLV and EDSS (P < .01) but not between NAWM T2 or texture and expanded disability status score (EDSS). Our study suggest that: (a) diffuse changes are present in NAWM, (b) texture analysis is unable to detect any subtle structure in the NAWM abnormalities, possibly because of the limited image resolution; (c) in the development of disability in MS, macroscopic lesions are more important than microscopic abnormalities in the NAWM.

Adult↗
PubMedDate not supplied

A reproducible repositioning method for serial magnetic resonance imaging studies of the brain in treatment trials for multiple sclerosis.

Serial MRI is an important measure of disease progression in evaluating the treatment of multiple sclerosis (MS). Accurate comparisons of scans for lesion activity and lesion volume require precise repositioning of patients. A simple, reproducible repositioning method is described. In a multicenter treatment trial of MS using beta-interferon-1b, this method has been successful, with only 1.1% of scans being rejected because of poor repositioning.

Adjuvants, Immunologic↗
PubMedDate not supplied

Nasal orientation device to control head movement during CT and MR studies.

Cooperative patients can often keep still during a long examination of the brain provided that they are given cues about their position in space. In a U-shaped head support, the only movements likely are rotation in the sagittal or transverse planes. These can be detected by a nasal orientation device (NOD), simply a ring around the nose, close but not touching. Any unintentional movement is felt on the nose by the patient, who can return to the original (nontouching) position. With this device the patient can keep immobile to within approximately +/- 2 mm during long examinations. We have used the NOD to improve the quality of dynamic Gd-DTPA scanning for the measurement of blood-brain barrier permeability. The NOD can be of value in any neurological imaging procedure that is currently degraded by head movement.

Head↗
PubMedDate not supplied

Correction of nonuniformity in images of the spine and optic nerve from fixed receive-only surface coils at 1.5 T.

OBJECTIVE: Our goal was to analyze the sources of nonuniform image intensity of two surface coil configurations used on a General Electric 1.5 T Signa scanner and to correct the major source. MATERIALS AND METHODS: Correction of receive coil nonuniform sensitivity is achieved using division by images of a uniform phantom. Patient images are transferred to a network of Sun workstations for routine correction by technologists. Spinal cord images, originally 512 x 512, are truncated to 128 x 512 to allow four slices to be copied onto one X-ray film. RESULTS: Images of the spinal cord, collected using a four coil multiarray, show marked coil-to-coil nonuniformity and a high signal level from subcutaneous tissue near the coils. After correction the cord has uniform intensity, with improved visualization in the posterior fossa and upper thoracic region, enabling more reliable detection of small intrinsic lesions as occur in multiple sclerosis. Images of the optic nerves, collected using a two coil array, show bright signal in the brain and subcutaneous tissue. After correction the images are more uniform. CONCLUSION: Nonuniformity in images of the spine can be corrected using division by a phantom image. Water phantoms must be restricted in size to avoid standing wave effects; for the optic nerves a cylindrical oil phantom 20 cm in diameter was used.

Artifacts↗