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T A Yousry

Publications and source records attributed to T A Yousry.

At least 19 recordsLinked to original sources
PubMed1999

Cerebroretinal vasculopathy mimicking a brain tumor: a case of a rare hereditary syndrome.

We report a 35-year-old man with hereditary cerebroretinal vasculopathy (CRV) characterized by retinal microvascular changes and a right frontal intracerebral mass lesion that suggested a brain tumor. Histopathologic analysis of the patient's brain lesion as well as reviewed specimens of the patient's mother, who had reportedly died of a brain tumor, showed no neoplasia but did show cerebral microvasculopathy. CRV should be considered as a differential diagnosis for patients with intracerebral mass lesions, retinal vascular changes, and a positive family history of "brain tumors."

Adult↗
PubMed1999

Quantitative MRI in CADASIL: correlation with disability and cognitive performance.

OBJECTIVE: To study correlations between total lesion load on brain MRI and clinical features, and to evaluate the influence of demographic variables on quantitative MRI variables in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). BACKGROUND: CADASIL is a hereditary form of small-vessel disease caused by mutations within the Notch3 gene. MRI abnormalities have been found both in asymptomatic and symptomatic CADASIL individuals. METHODS: Quantitative measurements on cerebral MRI were performed in 64 CADASIL individuals. MRI lesions were quantified using a semi-automated segmentation technique based on local thresholds. RESULTS: MRI total lesion volume correlated significantly with disability (Rankin Scale) on both T1- and proton density (PD)-weighted images. There was a significant inverse correlation between total lesion volume and overall cognitive performance as determined by the Mini-Mental State Examination. Age but not sex was correlated with lesion load both on T1- and PD-weighted images. There was no detectable influence of the Notch3 genotype on quantitative MRI variables. CONCLUSIONS: This study demonstrates correlations between MRI lesion volume and clinical characteristics in CADASIL. Longitudinal studies are now warranted to investigate whether quantitative MRI could be used as an adjunct outcome measure in future therapeutic trials in CADASIL.

Adult↗
PubMed1999

Correlation between enhancing lesion number and volume on standard and triple dose gadolinium-enhanced brain MRI scans from patients with multiple sclerosis.

We investigated the correlations between numbers and volumes of multiple sclerosis (MS) lesions enhancing on standard dose (SD) and triple dose (TD) gadolinium (Gd)-enhanced brain magnetic resonance imaging (MRI) scans, to clarify whether the measurement of enhancing lesion volumes or the use of TD MRI give additional information which can not be obtained by counting enhancing lesions on SD scans. SD and TD Gd-enhanced brain MRI scans were obtained every month for three months from 40 MS patients. The numbers of total and new enhancing lesions were counted, and the total volumes of enhancing lesions were measured from each of the four scans obtained with the two techniques. Univariate correlations between enhancing lesion numbers and volumes were assessed. The numbers of total and new enhancing lesions seen either on SD or TD scans were significantly correlated (r = 0.91 and 0.93, respectively). The numbers and volumes of total enhancing lesions were significantly correlated on both SD (r = 0.90), and TD (r = 0.89) scans. Moderate correlations were found between the total number of enhancing lesions on SD scans and the average difference between TD and SD scans for total enhancing lesion number (r = 0.66), and between the number of new enhancing lesions on SD scans and the average difference between TD and SD scans for new enhancing lesion number (r = 0.50). Our findings indicate that, both on SD and TD MRI, the counts and the volumes of total and new enhancing lesions are highly correlated, and that lesion counting may suffice to monitor MS activity. On the contrary, this study confirms the usefulness of TD MRI for a more complete assessment of the acute changes occurring in MS patients.

Brain↗
PubMed1999

Lesion load quantification on fast-FLAIR, rapid acquisition relaxation-enhanced, and gradient spin echo brain MRI scans from multiple sclerosis patients.

Previous studies have addressed the issue of the usefullness of fast fluid-attenuated (fast-FLAIR), rapid acquisition relaxation-enhanced (RARE), and gradient spin echo (GRASE) sequences in small groups of patients with multiple sclerosis (MS). The aim of this study was to assess and compare the lesion volumes and the intra-rater reproducibility of such measurements using fast-FLAIR, dual echo RARE, and dual echo GRASE brain scans from a large sample of MS patients. Using a 1.5 Tesla scanner, fast-FLAIR, dual echo RARE, and dual echo GRASE scans (24 axial, 5-mm thick contiguous interleaved slices) of the brain were obtained from 50 MS patients. Total lesion loads (TLL) were assessed twice using a semi-automated local thresholding segmentation technique by the same rater from the scans obtained with the three techniques. Mean TLL were 20.3 mL for fast-FLAIR, 16.6 mL for RARE, and 17.6 mL for GRASE sequences. Mean TLL detected by the three techniques were significantly heterogeneous (p < 0.001); at post-hoc analysis, the mean lesion volume detected on fast-FLAIR images was significantly higher than that on both RARE and GRASE images (p < 0.001) and the mean TLL on GRASE scans was significantly higher than that on RARE scans (p = 0.001). The mean values of intra-observer coefficient of variation for TLL measurements were similar for the three techniques (2.69% for fast-FLAIR, 2.33% for RARE, and 2.65% for GRASE). Our results confirm that fast-FLAIR sequences detect higher lesion volumes than those detected by other magnetic resonance imaging (MRI) sequences with shorter acquisition times. However, the reproducibility of TLL measurements is comparable among fast-FLAIR, RARE, and GRASE. This suggests that when assessing MS disease burden with MRI, the choice of the pulse sequence to be used should be dictated by the clinical setting.

Adult↗
PubMed1999

Statistical power of MRI monitored trials in multiple sclerosis: new data and comparison with previous results.

OBJECTIVES: To evaluate the durations of the follow up and the reference population sizes needed to achieve optimal and stable statistical powers for two period cross over and parallel group design clinical trials in multiple sclerosis, when using the numbers of new enhancing lesions and the numbers of active scans as end point variables. METHODS: The statistical power was calculated by means of computer simulations performed using MRI data obtained from 65 untreated relapsing-remitting or secondary progressive patients who were scanned monthly for 9 months. The statistical power was calculated for follow up durations of 2, 3, 6, and 9 months and for sample sizes of 40-100 patients for parallel group and of 20-80 patients for two period cross over design studies. The stability of the estimated powers was evaluated by applying the same procedure on random subsets of the original data. RESULTS: When using the number of new enhancing lesions as the end point, the statistical power increased for all the simulated treatment effects with the duration of the follow up until 3 months for the parallel group design and until 6 months for the two period cross over design. Using the number of active scans as the end point, the statistical power steadily increased until 6 months for the parallel group design and until 9 months for the two period cross over design. The power estimates in the present sample and the comparisons of these results with those obtained by previous studies with smaller patient cohorts suggest that statistical power is significantly overestimated when the size of the reference data set decreases for parallel group design studies or the duration of the follow up decreases for two period cross over studies. CONCLUSIONS: These results should be used to determine the duration of the follow up and the sample size needed when planning MRI monitored clinical trials in multiple sclerosis.

Adolescent↗
PubMed1999

Detailed magnetic resonance imaging anatomy of the cisternal segment of the abducent nerve: Dorello's canal and neurovascular relationships and landmarks.

OBJECT: The goal of this study was to identify reliably the cisternal segment of the abducent nerve by using the three-dimensional Fourier transform constructive interference in steady-state (3-D CISS) magnetic resonance (MR) imaging sequence to define landmarks that assist in the identification of the abducent nerve on MR imaging and to describe the nerve's relationship to the anterior inferior cerebellar artery (AICA). METHODS: A total of 26 volunteers underwent 3-D CISS MR imaging, and 10 of these volunteers also underwent MR angiography in which a time-of-flight sequence was used to identify the facial colliculus, the abducent nerve and its apparent origin, Dorello's canal, and the AICA. The authors identified the abducent nerve with certainty in 96% of 3-D CISS sequences obtained in the axial and sagittal planes and in 94% obtained in the coronal plane. The nerve emerged from the pontomedullary sulcus in 94% of cases. The facial colliculus could always be identified, and Dorello's canal was identified in 94% of cases. In 76.6% of cases, the abducent nerve was seen to contact the AICA, which passed inferior to the nerve in 63.8% of cases and superior to it in 29.8%. CONCLUSIONS: The anatomical course of the abducent nerve and its relationship to the AICA and other blood vessels can be reliably identified using a 3-D CISS MR sequence with the facial colliculus and Dorello's canal serving as landmarks.

Abducens Nerve↗
PubMed1999

Characteristic MR lesion pattern and correlation of T1 and T2 lesion volume with neurologic and neuropsychological findings in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

BACKGROUND AND PURPOSE: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an arteriopathy related to a genetic defect of the notch 3 gene on chromosome 19. The purpose of this study was to evaluate lesion distribution and volume using MR imaging and to correlate the lesion volume with the neurologic and neuropsychological findings. METHODS: Twenty members of two families (14 with CADASIL as determined by linkage analysis, six healthy) were studied with MR imaging. Two observers evaluated the MR findings semiquantitatively and quantitatively. MR results were then correlated with neurologic and neuropsychological findings. RESULTS: A typical pattern of lesion distribution in patients with CADASIL was found: the frontal lobe was the site with the highest lesion load, followed by the temporal lobe and the insula. The total lesion volume on T1-weighted MR images correlated significantly with the degree of disability and the degree of impairment in neuropsychological functions (including attention, memory, and conceptual and visuospatial functions). CONCLUSION: In CADASIL patients, a common pattern of cerebral lesion distribution is found. The total T1 lesion volume is an important parameter to correlate with disability, as it may prove to be helpful in predicting the natural history of the disease.

Adult↗
PubMed1998

Triple dose of gadolinium-DTPA increases the sensitivity of spinal cord MRI in detecting enhancing lesions in multiple sclerosis.

We compared the sensitivity of single and triple dose Gd-DTPA magnetic resonance imaging (MRI) in detecting enhancing lesions in the spinal cord of 13 patients with multiple sclerosis (MS). We detected two enhancing lesions in two of 13 (15%) patients when the single dose of Gd-DTPA was used and 12 lesions in five of 13 (38%) patients when the triple dose of Gd-DTPA was used. These results suggest that: (1) the use of triple dose increases the sensitivity of spinal cord MRI when studying relapsing-remitting or secondary progressive MS patients, (2) triple dose Gd-DTPA enhanced of the spinal cord MRI might be useful in monitoring disease activity in patients with MS.

Adult↗
PubMed1998

Correlations between monthly enhanced MRI lesion rate and changes in T2 lesion volume in multiple sclerosis.

Magnetic resonance imaging (MRI) provides a powerful tool for assessing disease activity in multiple sclerosis (MS), and its role as a surrogate marker for monitoring treatment efficacy is now becoming established. The most commonly used MRI parameters in treatment trials are (1) monthly gadolinium-enhanced MRI, with the number of active lesions serving as the outcome measure, and (2) annual lesion load quantification, in which change in MS lesion volume provides the MRI endpoint. We evaluated clinical/MRI correlations and the relationship between these two markers of disease activity in 73 patients with clinically definite MS. Quantification of T2 lesion load was performed at study entry and exit, with a median study duration of 11 months (range, 9 to 14 months). Monthly postgadolinium T1-weighted images were acquired between these time points. Lesion load at study entry was significantly correlated with the baseline Expanded Disability Status Scale (EDSS) score, but no significant longitudinal correlation was demonstrated. The number of enhancing lesions on the entry scan was predictive of subsequent relapse rate over the study duration and also correlated with the subsequent enhancing lesion activity over the study period. A significant correlation was found between change in lesion load and disease activity on the monthly scans. Our results suggest that annual lesion load quantification provides an efficient measure of ongoing disease activity, and this supports its application as a surrogate marker of disease evolution in phase III treatment trials.

Adolescent↗
PubMed1998

Neurological and neuroradiological findings in long-term survivors of allogeneic bone marrow transplantation.

The aim of this study was to assess neurological, neuropsychological, and neuroradiological findings in long-term survivors of allogeneic bone marrow transplantation (BMT) who were recruited from a hematological outpatient clinic. In addition, risk factors for the development of late neurological complications were identified. In contrast to previous studies on autopsied patients, our study design provoked a bias away from increased neurological sequelae, because patients with early complications after BMT were excluded. Fifty-nine allogeneic patients and 7 autologous BMT patients underwent clinical examination, short neuropsychological testing, and cranial magnetic resonance imaging (MRI) 34 +/- 26 months after BMT. The pathological results of the neurological examination (abnormal 64%) and the MRI examination (white matter lesions, 54%; atrophy, 11%) were associated with the occurrence of chronic graft-versus-host disease (GvHD) evolving from acute GvHD, with corticosteroid therapy and with cyclosporine medication. Neuropsychological impairment (cognitive deficits, 37%) was associated with long-term cyclosporine medication and age. No influence of pre-BMT disease, BMT donor status, or the conditioning regimen was found. These results suggest that the frequent neurological abnormalities in long-term survivors of allogeneic BMT are associated with chronic GvHD and with the resulting immunosuppression as major risk factors.

Adult↗
PubMed1998

Cerebral functional magnetic resonance imaging of vestibular, auditory, and nociceptive areas during galvanic stimulation.

Cerebral activation was investigated with functional magnetic resonance imaging (fMRI) during galvanic stimulation of the mastoid in 6 normal volunteers. Cutaneous stimulation at the neck C4-5 level served as a control. During mastoid stimulation, bilateral vestibular activation occurred in the posterior insula (parietoinsular vestibular cortex, PIVC), the transverse temporal (Heschl's) gyrus, and thalamic pulvinar. The cutaneous pain elicited by galvanic stimulation caused bilateral activity of the medial part of the insula and the anterior median thalamus. Thus, galvanic stimulation at the mastoid level activates cortical areas of three different sensory systems in the insulathalamic region, the vestibular, the auditory, and the nociceptive systems.

Adult↗
PubMed1998

Ictal technetium-99m ethyl cysteinate dimer single-photon emission tomographic findings and propagation of epileptic seizure activity in patients with extratemporal epilepsies.

Although ictal single-photon emission tomography (SPET) with technetium-99m ethyl cysteinate dimer (ECD) has a well-established role in the diagnostic evaluation of patients with temporal lobe epilepsy who are being considered for epilepsy surgery, its use in cases of extratemporal epilepsy is still limited. We investigated the influence of the propagation of extratemporal epileptic seizure activity on the regional increase in cerebral blood flow, which is usually associated with epileptic seizure activity. Forty-two consecutive patients with extratemporal epilepsies were prospectively evaluated. All patients underwent ictal SPET studies with simultaneous electroencephalography (EEG) and video recordings of habitual seizures and imaging studies including cranial magnetic resonance imaging and positron emission tomography with 2-[18F]-fluoro-2 deoxy-d-glucose. Propagation of epilptic seizure activity (PESA) was defined as the absence of hyperperfusion on ictal ECD SPET in the lobe of seizure onset, but its presence in another ipsilateral or contralateral lobe. Observers analysing the SPET images were not informed of the other results. PESA was observed in 8 of the 42 patients (19%) and was ipsilateral to the seizure onset in five (63%) of these eight patients. The time between clinical seizure onset and injection of the ECD tracer ranged from 14 to 61 s (mean 34 s). Seven patients (88%) with PESA had parieto-occipital epilepsy and one patient had a frontal epilepsy. PESA was statistically more frequent in patients with parieto-occipital lobe epilepsies (58%) than in the remaining extratemporal epilepsy syndromes (3%) (P<0.0002). These findings indicate that ictal SPET studies require simultaneous EEG-video recordings in patients with extratemporal epilepsies. PESA should be considered when interpreting ictal SPET studies in these patients. Patients with PESA are more likely to have parieto-occipital lobe epilepsy than seizure onset in other extratemporal regions.

Adolescent↗
PubMed1998

A multi-centre longitudinal study comparing the sensitivity of monthly MRI after standard and triple dose gadolinium-DTPA for monitoring disease activity in multiple sclerosis. Implications for phase II clinical trials.

In this study we assessed the safety, efficacy and cost-effectiveness of the use of triple dose gadolinium-DTPA (Gd) in serial monthly brain MRI of patients with multiple sclerosis, such as could be selected for clinical trials. The number of enhancing lesions, the number of new enhancing lesions and the number of active scans were used to evaluate the sensitivity of the contrast-enhanced MRI to disease activity. The dose of Gd, and the effect of introducing a delay between the contrast injection and the scan were both appraised. Every 4 weeks for 3 months, and in two separate sessions, scans were obtained from 40 patients with relapsing-remitting or secondary progressive multiple sclerosis, 5 min (early) and 20 min (delayed) after a standard dose (0.1 mmol/kg) or triple dose (0.3 mmol/kg) Gd injection. There were 435 enhancing lesions (242 of which were new) on the early standard dose scans, 479 (263 new) on the delayed standard dose, 772 (365 new) on the early triple dose and 827 (404 new) on the delayed triple dose. There were 109 scans revealing active disease on the early standard dose scans, 112 on the delayed standard dose, 119 on the early triple dose and 120 on the delayed triple dose. Statistical simulations indicated that the sample sizes needed for both cross-over and parallel-group trials with similar powers are lower if serial monthly triple dose MRI is used. No side-effects were reported and no significant changes in blood test parameters were found throughout the study. This study shows that the serial use of triple dose Gd is safe, and that it increases the sensitivity of serial monthly enhanced MRI in detecting multiple sclerosis activity significantly. Its use should enable preliminary trials of experimental therapies for multiple sclerosis to be conducted in small patient populations, over a short period of time.

Adult↗
PubMed1998

MRI evolution of new MS lesions enhancing after different doses of gadolinium.

OBJECTIVE: To investigate the evolution of multiple sclerosis (MS) lesions enhancing after single dose (SD) or triple dose (TD) of gadolinium-DTPA (Gd). MATERIAL AND METHODS: For 3 months, 30 relapsing-remitting MS patients underwent 2 monthly MRI sessions, consisting of Gd-enhanced T1-weighted scans, after SD (i.e., 0.1 mmol/kg) in one session and TD (i.e., 0.3 mmol/kg) in the other. New enhancing lesions on month 1 and month 2 follow-up scans were studied and for them any persistence of enhancement was evaluated on the scans obtained the next month. RESULTS: In all, 151 lesions enhancing after both SD and TD and 91 lesions enhancing only after TD entered the analysis. After 1 month, for the 151 lesions enhancing after both SD and TD, 73 (48%) were not enhancing, 50 (33%) were still enhancing after both SD and TD and 28 (19%) were enhancing only after TD. For the 91 lesions enhancing only after TD, 61 (67%; P<0.005) were not enhancing, 16 (18%; P<0.01) were still enhancing only after TD and 14 (15%; P=NS) showed enhancement after both SD and TD. CONCLUSION: Enhancing lesions in patients with MS are heterogeneous. Those enhancing only after TD of Gd are characterized by a milder and shorter opening of the blood-brain barrier.

Blood-Brain Barrier↗
PubMed1998

A preliminary study comparing the sensitivity of serial monthly enhanced MRI after standard and triple dose gadolinium-DTPA for monitoring disease activity in primary progressive multiple sclerosis.

We performed this study to evaluate and compare the numbers of total and new enhancing lesions detected on serial monthly brain magnetic resonance imaging (MRI) after the injection of a standard dose (SD) and a triple dose (TD) of gadolinium-DTPA (Gd) in patients with primary progressive multiple sclerosis (PPMS). Every 4 weeks for 3 months and in two separate sessions, MRI scans were obtained from 5 patients with PPMS, 5 (early) and 20 minutes (delayed) after SD (0.1 mmol/kg) or TD (0.3 mmol/kg) Gd injection. In 2 patients, T1-weighted scans with a magnetization transfer pulse (MT) after SD and TD injection were also obtained. There were 13 enhancing lesions (5 of which were new) on the early SD scans, 15 (5 new) on the delayed SD scans, 17 (6 new) on the early TD scans and 18 (7 new) on the delayed TD scans. TD MRI scans detected more enhancing lesions than SD scans in 3 patients (two of them were those with the lowest disability). The application of the MT pulse did not change the numbers of enhancing lesions seen after the injection of SD and TD of Gd in the remaining two patients. No side effects were reported and no significant changes in blood test parameters were found throughout the study. Our results suggest that serial monthly TD MRI, delayed scanning, MT T1-weighted scans or their combination, although safe, have a limited role for monitoring disease evolution in patients with PPMS.

Adult↗
PubMed1998

Common variable immunodeficiency leading to spinal subacute combined degeneration monitored by MRI.

A patient is reported on with a common variable immunodeficiency syndrome (CVID), in whom chronic gastritis with antibodies against parietal cells and a cytomegalovirus associated enteritis led to vitamin B12 deficiency with consecutive subacute combined degeneration of the spinal cord. The resulting medullary changes, most probably representing demyelination, were visualised with MRI. The effects of treatment were also monitored over three years by MRI and clinical examination. The resolution of the MRI changes correlated with clinical improvement of the patient's signs. In the medical literature only five cases of vitamin B12 related spinal cord changes have been identified by MRI; none was caused by a CVID syndrome.

Autoimmune Diseases↗
PubMed1998

The effect of cross-talk on MRI lesion numbers and volumes in multiple sclerosis using conventional and turbo spin-echo.

We measured and compared lesion numbers and volumes present on brain magnetic resonance imaging (MRI) scans of patients with multiple sclerosis (MS) acquired with contiguous (scheme A) and interleaved (scheme B) slice acquisition, to evaluate whether there was a gain in sensitivity using the second pattern of acquisition and whether this counterbalanced the doubled acquisition time. Conventional spin-echo (CSE) sequences were performed for eight patients and turbo spin-echo (TSE) sequences for ten. Acquisition scheme B detected 3.8% more lesions than acquisition scheme A (the increase was 3.1% for CSE and 4.5% for TSE). These differences were not statistically significant. No significant difference in lesion numbers was found when different lesion locations were also considered. Lesions volumes were significantly higher when scheme B was used (P = 0.024). This was due to higher lesion volumes on TSE images (P = 0.006), especially on even-numbered slices (P = 0.008). Inter-slice cross-talk has a negligible effect on lesion numbers and volume estimates in MS for CSE sequence, whilst it cannot be neglected when TSE sequences are used to measure MS lesion volume.

Adult↗