1/12. Quantitative follow-up of patients with multiple sclerosis using MRI: technical aspects.A highly reproducible automated procedure for quantitative analysis of serial brain magnetic resonance (MR) images was developed for use in patients with multiple sclerosis (MS). The intracranial cavity (ICC) was identified on standard dual-echo spin-echo brain MR images using a supervised automated procedure. MR images obtained from one MS patient at 24 time points in the course of a 1-year follow-up were aligned with the images of one of the time points. Next, the contents of the ICC in each MR exam were segmented into four tissues, using a self-adaptive statistical algorithm. Misclassifications due to partial voluming were corrected using a combination of morphologic operators and connectivity criteria. Finally, a connectivity detection algorithm was used to separate the tissue classified as lesions into individual entities. Registration, classification of the contents of the ICC, and identification of individual lesions are fully automatic. Only identification of the ICC requires operator interaction. In each MR exam, the program estimated volumes for the ICC, gray matter (GM), white matter (WM), white matter lesions (WML), and cerebrospinal fluid (CSF). The reproducibility of the system was superior to that of supervised segmentation, as evidenced by the coefficient of variation: CSF supervised 45.9% vs. automated 7.7%, GM 16.0% vs. 1.4%, WM 15.7% vs. 1.3%, and WML 39.5% vs 52.0%. Our results demonstrate that this computerized procedure allows routine reproducible quantitative analysis of large serial MRI data sets.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
2/12. Middle-ear myoclonus.tinnitus produced by repetitive contraction of the middle-ear muscles is a rare condition. We present an interesting case of bilateral middle-ear myoclonus causing incapacitating tinnitus in a patient with multiple sclerosis. Otological examination demonstrated rhythmic involuntary movement of the tympanic membrane. These movements correlated with a rhythmic 'rushing wind' noise perceived by the patient. Oropharyngeal examination showed no evidence of palatal myoclonus. Impedance audiometry confirmed rhythmic change in the middle-ear volume. Medical management was unsuccessful. The patient's tinnitus was subsequently cured with bilateral sectioning of the tensor tympani and stapedial tendons.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
3/12. Confabulation and multiple sclerosis: a rare association.BACKGROUND: Fantastic confabulation in the context of multiple sclerosis (MS) has not previously been reported in the literature. The association is of interest because clearly demonstrable brain pathology in MS together with other cognitive and behavioural correlates may further our understanding of the neural basis underlying confabulation. methods: A single case report with magnetic resonance imaging of the brain and detailed neuropsychological evaluation. RESULTS: Confabulation occurred together with disinhibited and stimulus bound behaviour. While the patient's physical and emotional state limited the range of psychometric tests administered, the results revealed an inability to maintain focused, regulated information processing. Although memory difficulties were present, they were not in the nature of a severe amnesic disorder. The patient appeared to have a broad fund of knowledge, but the associations binding the information together and putting it into context were loose. All three features of a triad of responses previously described in confabulating patients were present, namely an inability to withhold answers, to monitor one's own responses and provide verbal self corrections. MRI of the brain showed bilateral periventricular lesions and discrete frontal lesions with 53% of the total lesion volume distributed in frontal areas. Cortical atrophy, most marked in frontal regions also was conspicuous. CONCLUSIONS: Confabulation linked to frontal lobe involvement may occur as part of the changes in mentation found in MS. It is, however, rare and although associated with impaired memory, may be found in the absence of a severe amnesic disorder. This conclusion is discussed in the light of observations from the literature suggesting that frontal involvement is a prerequisite before fantastic confabulation occurs.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
4/12. Quantitative proton magnetic resonance spectroscopy of focal brain lesions.The diagnostic value of single-voxel proton magnetic resonance spectroscopy (2 T, stimulated echo acquisition mode, TR = 6,000 ms, TE = 20 ms, 4-5 mL volumes-of-interest) was assessed for a differentiation of focal brain lesions of unknown etiology in 17 patients 1-14 years of age. Absolute metabolite concentrations were compared with age-matched control subjects and an individual control region. Most of the brain tumors were characterized by strongly reduced total N-acetylaspartyl compounds and marked increases of myo-inositol and choline-containing compounds, consistent with a lack of neuroaxonal tissue and a proliferation of glial cells. Lactate was elevated in only four patients. When using this pattern for a metabolic discrimination of brain tumors from other focal lesions, proton spectroscopy correctly identified 14 of 17 abnormalities, as confirmed by histologic examination after neurosurgical intervention. One false-positive tumor diagnosis was a severe reactive gliosis mimicking a typical tumor spectrum. Two inconclusive cases comprised an astrocytoma with moderately elevated myo-inositol but reduced choline-containing compounds and a patient with an abscess leading to a marked reduction of all metabolites but strong contributions from mobile lipids. In summary, quantitative proton spectroscopy has considerable clinical value for preoperative characterization of focal brain lesions.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
5/12. Evidence for shutter-speed variation in CR bolus-tracking studies of human pathology.The standard pharmacokinetic model for the analysis of MRI contrast reagent (CR) bolus-tracking (B-T) data assumes that the mean intracellular water molecule lifetime (tau(i)) is effectively zero. This assertion is inconsistent with a considerable body of physiological measurements. Furthermore, theory and simulation show the B-T time-course shape to be very sensitive to the tau(i) magnitude in the physiological range (hundreds of milliseconds to several seconds). Consequently, this standard model aspect can cause significant underestimations (factors of 2 or 3) of the two parameters usually determined: K(trans), the vascular wall CR transfer rate constant, and v(e), the CR distribution volume (the extracellular, extravascular space fraction). Analyses of animal model data confirmed two predicted behaviors indicative of this standard model inadequacy: (1) a specific temporal pattern for the mismatch between the best-fitted curve and data; and (2) an inverse dependence of the curve's K(trans) and v(e) magnitudes on the CR dose. These parameters should be CR dose-independent. The most parsimonious analysis allowing for realistic tau(i) values is the 'shutter-speed' model. Its application to the experimental animal data essentially eliminated the two standard model signature inadequacies. This paper reports the first survey for the extent of this 'shutter-speed effect' in human data. Retrospective analyses are made of clinical data chosen from a range of pathology (the active multiple sclerosis lesion, the invasive ductal carcinoma breast tumor, and osteosarcoma in the leg) that provides a wide variation, particularly of K(trans). The signature temporal mismatch of the standard model is observed in all cases, and is essentially eliminated by use of the shutter-speed model. Pixel-by-pixel maps show that parameter values from the shutter-speed analysis are increased by more than a factor of 3 for some lesion regions. This endows the lesions with very high contrast, and reveals heterogeneities that are often not seen in the standard model maps. Normal muscle regions in the leg allow validation of the shutter-speed model K(trans), v(e), and tau(i) magnitudes, by comparison with results of previous careful rat leg studies not possible for human subjects.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
6/12. multiple sclerosis and asymptomatic urinary tract infection.multiple sclerosis patients with bladder dysfunction are prone to have an asymptomatic urinary tract infection. Because bladder function abnormalities occur at some time in 70% to 90% of multiple sclerosis patients, a quantitative estimate of the bacterial concentration in the urine as well as a culture is mandatory. Treatment of bladder dysfunction or infection will vary according to the post-voiding residual volume. A patient with multiple sclerosis and asymptomatic urinary tract infection is reported that highlights strategies for the diagnosis and treatment of the urinary tract infection.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
7/12. Intermittent positive pressure ventilation via nasal access in the management of respiratory insufficiency.These are preliminary observations of the introduction of a new technique of noninvasive positive pressure respiratory support for patients with subacute or chronic respiratory failure. Clinical situations where intubation or tracheostomy may have been performed were managed by intermittent positive pressure ventilation via nasal access (NIPPV) with a CPAP mask, or a custom constructed Vel-Foam nose piece. Four patients were managed at home with the use of portable volume ventilators. One patient employed the technique while hospitalized with subacute respiratory failure. Two patients, otherwise dependent on mouth intermittent positive pressure ventilation (MIPPV) 24 hours a day, received necessary dental care with NIPPV support. In a large population with a decade or more follow-up, MIPPV was shown to be an effective noninvasive technique to support respiration in patients with the most severe paralytic respiratory failure. Preliminary observations suggest that NIPPV may compare favorably with MIPPV and deserves more widespread study and application.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
8/12. Dorsal midbrain syndrome in multiple sclerosis with magnetic resonance imaging correlation.We describe the clinical characteristics and a series of magnetic resonance imaging (MRI) studies in a patient with the features of dorsal midbrain syndrome occurring in the setting of multiple sclerosis. A T2-weighted MRI study revealed a discrete abnormality in the tectum of the midbrain whereas a high volume delayed computed tomography (CT) scan was uninformative. In parallel with remission of the clinical findings, the MRI abnormality diminished over time and was no longer visible at one year suggesting that some MRI detected MS lesions can completely disappear with time. This report demonstrates the use of MRI to detect and to follow sequentially sites of known disease activity in MS.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
9/12. Correlates of brain-stem oculomotor disorders in multiple sclerosis. magnetic resonance imaging.Three patients with focal brain-stem oculomotor disturbances (nuclear sixth nerve syndrome, sixth nerve palsy, bilateral internuclear ophthalmoplegia) as a consequence of multiple sclerosis have been studied with high-volume delayed computed tomography and high-field magnetic resonance imaging. In all of them, high-volume delayed computed tomography was inconclusive in the brain stem, but magnetic resonance imaging showed an area of prolonged T1 and/or T2 in the region appropriate to the oculomotor findings. magnetic resonance imaging is the imaging technique of choice of small plaques in the brain stem. It can considerably aid clinicotopographic correlation in multiple sclerosis.- - - - - - - - - - ranking = 2keywords = volume (Clic here for more details about this article) |
10/12. Unsuspected (clinically silent) multiple sclerosis. Quantitative investigations in one autoptic case.The incidental retrieval of a few, well-circumscribed, chronic multiple sclerosis plaques in a 49-year-old female who died from myocardial infarct is reported. In serial gallocyanin stained frontal sections of the brain one plaque in the left and four plaques in the right hemisphere were encountered. A total of 1.25 cm3 or 0.24% of the right hemispheric volume and a total of 0.93 cm3 or 0.2% of the left hemispheric volume was afflicted. The size as well as the topography of the plaques could explain the absence of clinical symptoms. Methodological issues concerning in vivo and post mortem diagnosis of multiple sclerosis and their impact on the epidemiology of this disease are discussed.- - - - - - - - - - ranking = 2keywords = volume (Clic here for more details about this article) |
| | Next -> |