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T Yousry

Publications and source records attributed to T Yousry.

At least 19 recordsLinked to original sources
PubMed2001

Clinical-MRI correlations in a European trial of interferon beta-1b in secondary progressive MS.

BACKGROUND: The recently completed placebo-controlled multicenter randomized trial of interferon beta-1b (Betaferon) in 718 patients with secondary progressive MS shows significant delay of disease progression and reduction of relapse rate. This study provides an opportunity to assess the level of relationship between clinical and MRI outcomes in this cohort of patients with secondary progressive MS. METHODS: Brain T2-weighted lesion volume was measured annually in all available patients, with visual analysis to identify any new or enlarging (active) T2 lesions at each annual time point. A subgroup of 125 patients had monthly gadolinium-enhanced, T1-weighted imaging at months 0 to 6 and 18 to 24. Relapses were documented and expanded disability status scale (EDSS) was measured every 3 months. RESULTS: For the annual MRI outcomes, a significant but modest correlation was identified between the change in T2 lesion volume from baseline to the final scan and the corresponding change from baseline in EDSS (r = 0.17, p < 0.0001). There were significant correlations between the cumulative number of active T2 lesions and 1) change in EDSS (r = 0.18, p < 0.0001) and 2) relapse rate (r = 0.24, p < 0.0001). In the subgroup of 125 patients undergoing monthly imaging, MRI lesion activity was correlated with relapse rate over months 0 to 24 (r = 0.24, p = 0.006) but not with change in EDSS. CONCLUSIONS: These results confirm that the clinical-MRI relationships previously identified in relapsing-remitting MS still are apparent in the secondary progressive phase of the disease and support the use of MRI as a relevant outcome measure. In view of the relatively modest nature of the correlations, it seems unwise to rely on such MRI measures alone as primary efficacy variables in secondary progressive MS trials.

Brain↗
PubMed2001

T(1) hypointense lesions in secondary progressive multiple sclerosis: effect of interferon beta-1b treatment.

Recently, the clinical efficacy of interferon beta-1b (IFNbeta-1b) was demonstrated for secondary progressive (SP) multiple sclerosis in a European multicentre study. We evaluated the effect of IFNbeta-1b treatment on the rate of development of hypointense T(1) MRI lesions, a putative marker of axonal damage. Unenhanced T(1)-weighted images were obtained in a subgroup of 95 multiple sclerosis patients from five centres at 6-month intervals; this subgroup was similar to the total study population for all demographic, clinical and MRI parameters. An experienced observer blinded to the clinical data and treatment allocation measured volumes. The median baseline lesion load for hypointense T(1) lesions was 5.1 cm(3) for placebo-treated and 4.9 cm(3) for IFNbeta-1b-treated patients (P = 0.56). Placebo-treated patients showed an increase in T(1) lesion load by a median of 14% per year (P = 0.0002 compared with baseline); this was reduced to 7.7% per year in the IFNbeta-1b-treated patients (P = 0.003 versus placebo). In the IFNbeta-1b arm there was a statistically significant correlation between absolute change in Expanded Disability Status Scale scores and T(1) lesion load by month 36 (r = 0.38, P = 0.0015). In patients with SP multiple sclerosis, IFNbeta-1b treatment reduces the development of hypointense T(1) lesions, suggesting that reduced axonal damage in lesions may play a part in the beneficial effect that is observed clinically.

Adult↗
PubMed2001

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy: decrease in regional cerebral blood volume in hyperintense subcortical lesions inversely correlates with disability and cognitive performance.

BACKGROUND AND PURPOSE: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an arteriopathic syndrome related to a genetic defect on chromosome 19. Characteristic changes in CADASIL can be observed onT2-weighted MR images in the subcortical white matter. The purpose of this study was to measure changes of regional cerebral blood volume (rCBV) with dynamic contrast-enhanced MR imaging and to correlate the changes to disability and cognitive performance. METHODS: We obtained rCBV measurements of 24 individuals with proven CADASIL on a 1.5-T MR imaging unit. A susceptibility-weighted MR imaging sequence was used for bolus tracking. Principles of the indicator dilution theory were applied to estimate values of absolute rCBV (mL/100 g). Disability was determined by using the Rankin scale, and overall cognitive performance was assessed by using the Mini-Mental State Examination. RESULTS: The mean rCBV in the subcortical white matter that was hyperintense on the T2-weighted images (2.7 +/- 0.8 mL/100 g) was significantly lower than the rCBV in the white matter that appeared normal on the T2-weighted images (4.4 +/- 1.3 mL/100 g) (P <.05). The mean rCBV in the gray matter was within the normal range (8.3 +/- 1.7 mL/100 g). Both cognitive impairment and disability negatively correlated with rCBV in the subcortical white matter that was hyperintense (P <.05) but not with rCBV in the normal appearing white matter. rCBV did not correlate with age. CONCLUSION: rCBV measured in the hyperintense subcortical white matter in individuals with CADASIL was decreased and inversely correlated with disability and cognitive impairment.

Adult↗
PubMed2000

The use of magnetic resonance imaging in multiple sclerosis treatment trials: power calculations for annual lesion load measurement.

Phase III definitive treatment trials of new multiple sclerosis (MS) therapies now routinely incorporate an annual magnetic resonance imaging protocol, with change in T2-weighted brain lesion load providing an important outcome measure. To date the accepted strategy has been to perform a core imaging protocol on all patients in such studies. The aim of this study was to provide power calculations based on this MRI endpoint. Serial MRI data from 128 patients with either relapsing remitting (RR) or secondary progressive (SP) MS were used to calculate sample size requirements using a repeated measures analysis of variance design. We provide sample size calculations based on various follow-up intervals and effect sizes. Sample sizes for the SPMS cohort were substantially larger than for the RRMS group, reflecting the greater variance in lesion load changes between patients in the SPMS group. With a follow-up of 3 years, we estimate that only 12 and 33 patients per arm are needed to show stabilisation of MRI lesion load in the RRMS and SPMS groups, respectively. Our results suggest that ongoing phase III treatment trials are more than adequately powered to detect even subtle treatment effects, and indicate that incorporating measurements from longer follow-up durations increases power substantially. We conclude that an annual imaging protocol provides a robust and powerful tool for assessing effects on the radiological appearance of the disease process.

Brain↗
PubMed2000

The effect of interferon beta-1b treatment on MRI measures of cerebral atrophy in secondary progressive multiple sclerosis. European Study Group on Interferon beta-1b in secondary progressive multiple sclerosis.

The recently completed European trial of interferon beta-1b (IFNbeta-1b) in patients with secondary progressive multiple sclerosis (SP multiple sclerosis) has given an opportunity to assess the impact of treatment on cerebral atrophy using serial MRI. Unenhanced T(1)-weighted brain imaging was acquired in a subgroup of 95 patients from five of the European centres; imaging was performed at 6-month intervals from month 0 to month 36. A blinded observer measured cerebral volume on four contiguous 5 mm cerebral hemisphere slices at each time point, using an algorithm with a high level of reproducibility and automation. There was a significant and progressive reduction in cerebral volume in both placebo and treated groups, with a mean reduction of 3.9 and 2.9%, respectively, by month 36 (P = 0.34 between groups). Exploratory subgroup analyses indicated that patients without gadolinium (Gd) enhancement at the baseline had a greater reduction of cerebral volume in the placebo group (mean reduction at month 36: placebo 5.1%, IFNbeta-1b 1.8%, P < 0.05) whereas those with Gd-enhancing lesions showed a trend to greater reduction of cerebral volume if the patient was on IFNbeta-1b (placebo 2.6%, IFNbeta-1b 3.7%; P > 0.05). These results are consistent with ongoing tissue loss in both arms of this study of secondary progressive multiple sclerosis. This finding is concordant with previous observations that disease progression, although delayed, is not halted by IFNbeta. The different pattern seen in patients with and without baseline gadolinium enhancement suggests that part of the cerebral volume reduction observed in IFNbeta-treated patients may be due to the anti-inflammatory/antioedematous effect of the drug. Longer periods of observation and larger groups of patients may be needed to detect the effects of treatment on cerebral atrophy in this population of patients with advanced disease.

Adult↗
PubMed1999

[Diagnosis and treatment of cranial arteriovenous dural fistulas].

DAVF are difficult to recognize with CT- or MR-imaging. Diagnosis is often possible by arterial MRA. The type of the venous drainage as demonstrated by DSA is relevant for the clinical decision. Most often the endovascular occlusion of the affected venous segment a suitable therapeutical approach.

Angiography, Digital Subtraction↗
PubMed1999

Echo-planar magnetic resonance imaging (EPI) with high-resolution matrix in intra-axial brain tumors.

The aim of this study was to assess the potential of high-speed interleaved echo-planar imaging (EPI) to achieve diagnostic image quality comparable to T2-weighted imaging in patients with brain tumors. Seventeen patients with intra-axial, supratentorial tumors (10 untreated gliomas, 7 radiated gliomas) were investigated on a 1. 5-T scanner. The conventional scan (SE, TR/TE = 2200/80 ms, 18 slices) was acquired in 8 min, 4 s, and EPI (TR/TE = 3000/80 ms, 18 slices) was completed in 25 s. The films were compared in a blinded trail by three radiologists. On the general impression and anatomic display, both sequences were rated to be of similar quality. Artifacts were slightly more pronounced at the skull base and around surgical clips using EPI. Tumor delineation was nearly equivalent using EPI, compared with the T2-weighted sequence. Echo-planar imaging reached diagnostic quality in all patients. Interleaved high-resolution EPI yielded sufficient quality to depict intra-axial, supratentorial brain tumors. Since EPI can be obtained in a small fraction of the time needed for conventional spin echo, in addition to other indications it could be considered to study patients unable to cooperate.

Artifacts↗
PubMed1998

Intraobserver and interobserver variability in schemes for estimating volume of brain lesions on MR images in multiple sclerosis.

PURPOSE: Our goal was to evaluate the intraobserver and interobserver reproducibility of measurements of brain lesion load in multiple sclerosis (MS) by using two proposed acquisition schemes. METHODS: Three-millimeter-thick conventional spin-echo (CSE) and fast fluid-attenuated inversion-recovery (FLAIR) sequences were obtained and the lesions segmented using a semiautomated technique based on local thresholding to calculate intraobserver and interobserver reproducibility. These were compared with images obtained from two separate MR units in which 5-mm CSE sequences were obtained and segmented by using the local thresholding technique and also by manual outlining. RESULTS: The intraobserver coefficient of variation was 4.0% (95% confidence interval [CI], 3.0% to 4.5%) for the 5-mm CSE sequence measured with manual outlining, 3.1% (95% CI, 2.5% to 3.2%) and 5.1% (95% CI, 4.1% to 5.6%) for the two sets of 5-mm CSE sequences measured using the local thresholding technique, 5.7% (95% CI, 3.9% to 6.6%) for the 3-mm CSE sequence, and 2.6% (95% CI, 2.1% to 2.7%) for the fast FLAIR sequence. The interobserver coefficient of variation was 7.1% (95% CI, 4.9% to 8.7%) and 8.3% (95% CI, 6.4% to 9.6%) for the two sets of 5-mm CSE sequences, 7.3% (95% CI, 4.7% to 9.1%) for the 3-mm CSE sequence, and 2.9% (95% CI, 2.3% to 3.3%) for the fast FLAIR sequence. The intraobserver and interobserver reproducibility of measurements obtained with the fast FLAIR technique was significantly better than those obtained with the other techniques. CONCLUSIONS: Our data indicate that the intraobserver and interobserver variability in quantifying MS lesions can be reduced significantly with the use of fast FLAIR sequences, while no significant improvement is gained by reducing the section thickness from 5 mm to 3 mm.

Adult↗
PubMed1997

Dural arteriovenous fistulas including the transverse and sigmoid sinuses: results of treatment in 30 cases.

We report about the treatment and outcome of 30 patients with dural arteriovenous fistulas including the transverse and sigmoid sinuses treated between 1986 and 1995. All patients underwent panangiography for definitive diagnosis. The dAVF were supplied by the external carotid artery system alone (14 patients), both external and internal carotid systems (10 patients) or both anterior and posterior circulation (6 patients). Depending on the venous drainage the fistulas were classified following a modification of Djindjian's description with 18 patients revealing Type I (main sinus with antegrade flow), 5 Type II a (main sinus with reflux into the contralateral sinus). 5 Type II b (cortical veins), 1 Type II a+b (both) and 1 of Type III (direct cortical drainage). Bruit, pulsatile tinnitus and headaches were the most common symptoms. 6 patients presented with intracranial haemorrhage, 4 with progressive neurological deficit or seizures and 3 with dementia. Arterial embolization was performed in all cases except one, where a transvenous approach for balloon occlusion of the transverse sinus was performed. 21 patients were treated by single or repeated embolization alone. Only in 9/21 cases did arterial embolization result in complete occlusion of the fistula. In 12/21 patients incomplete occlusion was achieved. Following embolization 8 patients underwent additional surgery including coagulation of the feeding arteries and arterialized veins, sinus resection and reconstruction of the sinus. Overall, 18 patients were cured, 11 improved and 1 patient was unchanged. There was a total number of 5 complications including transient stroke, transient facial nerve palsy, and a small necrotic skin area following embolization. Venous infarction of the occipital lobe was induced by transvenous occlusion and surgical resection of the transverse sinus in one patient each, respectively. From our results we conclude that the endovascular therapy alone is the treatment of choice in case of Type I fistulas. In dAVF of Type II and III repeated endovascular treatment seems not to be sufficient and additional surgery is necessary.

Adolescent↗
PubMed1997

[Spiral CT angiography in demonstration of cerebral aneurysms before and after treatment with titanium clips].

PURPOSE: To determine the suitability of spiral CT angiography (SCTA) in patients with intracerebral titanium aneurysm clips. MATERIAL AND METHOD: The section parameters were optimised using a phantom. 16 patients were examined preoperatively and 18 following treatment of aneurysms with clips. RESULTS: The resolution, sensitivity and specificity for demonstrating cerebral aneurysms measuring > or = 3 mm was 91.3% and 75% respectively. In 15 patients with intracerebral clips there were no or only minor artefacts; three examinations were of no value because of major metal artefacts. Amongst six aneurysms demonstrated angiographically, two, which measured more than 3 mm, could be shown by SCTA. CONCLUSION: SCTA was able to demonstrate intracerebral aneurysms measuring > or = 3 mm. Titanium clips did not usually affect image quality significantly.

Adolescent↗
PubMed1997

Radical resection of meningiomas and arteriovenous fistulas involving critical dural sinus segments: experience with intraoperative sinus pressure monitoring and elective sinus reconstruction in 10 patients.

OBJECTIVE: Radical resection of meningiomas and dural arteriovenous fistulas involving functional major dural sinuses entails the risk of intracranial hypertension and venous infarction. Surgical reconstruction of dural sinuses and bridging veins increases the spectrum of dural sinus conditions that can be treated by complete resection, but indications for venous reconstructions and associated risks are still not well defined. We report our experience with sinus reconstruction based on the intraoperative assessment of collateral venous flow. METHODS: Radical resection of meningiomas (n = 5) or dural arteriovenous fistulas (n = 5) involving critical segments of dural sinuses was performed in 10 patients. All but two patients were suffering from recurrent disease after incomplete treatment. Tolerance of sinus occlusion was assessed intraoperatively by measuring stump pressure in the superior sagittal sinus during test clamping of the involved sinus segment. RESULTS: In five patients, the results of pressure monitoring suggested that occlusion of the sinus might not be tolerated. In two other patients, major bridging veins entered the diseased segment. In these patients, the resected sinus segment was reconstructed and bridging veins were reinserted as far as possible. Postoperative graft occlusion occurred in two patients. One patient who was managed without reconstruction sustained a transient postoperative neurological deficit resulting from venous congestion in the vein of Labbé. Postoperative imaging confirmed total elimination of the pathological process in all 10 patients. There was no recurrence of disease during follow-up periods of up to 8 years. CONCLUSION: The monitoring of sinus pressure, together with the possible reconstruction of the diseased sinus, allows complete surgical treatment of dural sinus abnormalities and involves acceptable risk.

Adolescent↗
PubMed1997

Sensitivity of delayed gadolinium-enhanced MRI in multiple sclerosis.

INTRODUCTION: We performed this study to define the sensitivity of delayed gadolinium-enhanced magnetic resonance imaging (MRI) in detecting active lesions in the brains of patients with multiple sclerosis (MS). MATERIAL AND METHODS: T1-weighted images were obtained in 27 patients with relapsing-remitting or secondary progressive MS before, 5-7 min and 20-30 min after the injection of 0.1 mmol/kg gadolinium-DTPA. RESULTS: One-hundred-and-three enhancing lesions were found on the early and 110 on the delayed scans (increase=6.4%). Six patients had 8 additional lesions in the delayed scans, while 1 patient had 1 more lesion on the early scan. Two of the 12 (17%) patients with no enhancing lesions on the early scans had 2 enhancing lesions on the delayed scans. The average increase of enhancing lesion detection with delayed scanning was 14.5% for those patients who already had enhancing lesions on the early post-contrast scans. A significant increase of the enhancing lesion volume was found with delayed scanning (P=0.004). CONCLUSION: These data indicate that it is possible to increase MRI sensitivity in detecting MS active lesions by delaying the scanning after gadolinium injection.

Adult↗
PubMed1997

Sensitivity and reproducibility of fast-FLAIR, FSE, and TGSE sequences for the MRI assessment of brain lesion load in multiple sclerosis: a preliminary study.

Fast fluid-attenuated inversion recovery (fast-FLAIR), fast spin echo (FSE), and turbo-gradient spin echo (TGSE), new pulse sequences for magnetic resonance imaging (MRI), are able to display multiple sclerosis (MS) lesions more conspicuously (fast-FLAIR) and with shorter imaging times (FSE, TGSE) than is conventional spin-echo MRI. In this study, we scanned 7 MS patients, using fast-FLAIR (18 axial brain slices), FSE (27 slices), and TGSE (9 slices) sequences in the same session, to compare the brain MRI lesion loads detected by these different sequences and the intraobserver reproducibility of these measurements. On the subset of slices (n = 9) covered by all three measurements, the mean lesion load was 7.577 mm3 on fast-FLAIR, 5.248 mm3 on FSE, and 3.080 mm3 on TGSE (p = 0.006) sequences. The mean intraobserver coefficients of variation were 2.92% for fast-FLAIR, 2.86% for FSE, and 4.31% for TGSE (not significant). These findings demonstrate that both fast-FLAIR and FSE sequences may be potentially useful for serial MRI studies for monitoring clinical trials, while TGSE might be useful for speeding diagnostic MRI in MS patients. Longitudinal, clinically correlated studies using these new MRI sequences are needed to confirm these preliminary data.

Brain↗
PubMed1997

Single-dose gadolinium with magnetization transfer versus triple-dose gadolinium in the MR detection of multiple sclerosis lesions.

PURPOSE: To compare the efficacy of single-dose gadolinium with magnetization transfer contrast (MTC) with that of triple-dose gadolinium in detecting enhancing multiple sclerosis lesions. METHODS: Twenty-one patients with multiple sclerosis were examined with MR imaging first with 0.1 mmol/kg gadolinium (single dose) and then, after 24 to 72 hours, with 0.3 mmol/kg gadolinium (triple dose). T2-weighted fast spin-echo and T1-weighted spin-echo MR images with and without MTC were obtained before contrast administration followed by either T1-weighted spin-echo images with MTC (single dose) or conventional T1-weighted spin-echo images (triple dose), starting 5, 17, and 29 minutes after contrast administration. All images were evaluated in a blinded fashion and scored in random order by two readers. Outcome parameters included number of enhancing lesions, number of active MR examinations (those containing at least one enhancing lesion), contrast ratio (signal intensity of enhancing lesion divided by signal intensity of normal-appearing white matter), and size of enhancing lesions. RESULTS: Eighty-one percent more enhancing lesions and 49% more active MR examinations were detected when a triple dose of gadolinium was used as compared with a single dose. The level of agreement between readers as to the number of enhancing lesions was significantly higher for triple-dose than for single-dose gadolinium. With triple-dose gadolinium, contrast ratios and areas of enhancement increased by 10% and 33%, respectively. Delayed imaging increased the size of the lesion by 11% on single-dose MTC images and by 18% on triple-dose images. CONCLUSION: Triple-dose gadolinium is more effective (higher sensitivity and interobserver agreement) than single-dose gadolinium in combination with MTC in detecting enhancing multiple sclerosis lesions.

Adult↗
PubMed1996

A high-resolution three-dimensional T1-weighted gradient echo sequence improves the detection of disease activity in multiple sclerosis.

In this study, we performed a post-contrast magnetization-prepared rapid acquisition gradient echo (MP RAGE) sequence with subsequent reconstruction of axial slices with 5-, 3-, and 1-mm thickness in 26 patients with multiple sclerosis (MS) to investigate the disease activity going on below the resolution of conventional scans. One hundred three enhancing lesions were detected using MP RAGE reconstructed with 1-mm-thick slices, 93 using MP RAGE reconstructed with 3-mm-thick slices and 82 using MP RAGE reconstructed with 5-mm-thick slices. The detection rate using 1-mm MP RAGE was 25.6% higher compared with 5-mm MP RAGE and 12% higher compared with 3-mm MP RAGE. Using 1-mm MP RAGE, we detected five enhancing lesions in 2 of the 12 patients (16.6%) who showed no enhancing lesions on the 5-mm MP RAGE and one enhancing lesion in 1 of the 10 patients (10%) who showed no enhancing lesions on the 3-mm MP RAGE. The increased sensitivity of 1-mm MP RAGE over the other two reconstruction slice thicknesses was due to improved detection of small lesions, located mainly in cortical/subcortical areas. These data indicate that the size of enhancing lesions in MS is highly variable, and that a significant proportion of disease activity goes undetected when performing conventional scans.

Adult↗