[Show abstract][Hide abstract] ABSTRACT: This pictorial essay highlights the role of the radiologist as a member of the adult epilepsy multidisciplinary team, and gives an overview of MRI-evident epileptogenic lesions.
Journal of Medical Imaging and Radiation Oncology 01/2014; · 0.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Changes in collateral blood flow, which sustains brain viability distal to arterial occlusion, may impact infarct evolution but have not previously been demonstrated in humans. We correlated leptomeningeal collateral flow, assessed using novel perfusion magnetic resonance imaging (MRI) processing at baseline and 3 to 5 days, with simultaneous assessment of perfusion parameters. Perfusion raw data were averaged across three consecutive slices to increase leptomeningeal collateral vessel continuity after subtraction of baseline signal analogous to digital subtraction angiography. Changes in collateral quality, Tmax hypoperfusion severity, and infarct growth were assessed between baseline and days 3 to 5 perfusion-diffusion MRI. Acute MRI was analysed for 88 patients imaged 3 to 6 hours after ischemic stroke onset. Better collateral flow at baseline was associated with larger perfusion-diffusion mismatch (Spearman's Rho 0.51, P<0.001) and smaller baseline diffusion lesion volume (Rho -0.70, P<0.001). In 30 patients without reperfusion at day 3 to 5, deterioration in collateral quality between baseline and subacute imaging was strongly associated with absolute (P=0.02) and relative (P<0.001) infarct growth. The deterioration in collateral grade correlated with increased mean Tmax hypoperfusion severity (Rho -0.68, P<0.001). Deterioration in Tmax hypoperfusion severity was also significantly associated with absolute (P=0.003) and relative (P=0.002) infarct growth. Collateral flow is dynamic and failure is associated with infarct growth.Journal of Cerebral Blood Flow & Metabolism advance online publication, 8 May 2013; doi:10.1038/jcbfm.2013.77.
Journal of cerebral blood flow and metabolism: official journal of the International Society of Cerebral Blood Flow and Metabolism 05/2013; · 5.46 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND AND PURPOSE:Intracerebral hemorrhage growth independently predicts disability and death. We hypothesized that noncontrast quantitative CT densitometry reflects active bleeding and improves predictive models of growth.MATERIALS AND METHODS:We analyzed 81 of the 96 available baseline CT scans obtained <3 hours post-ICH from the placebo arm of the phase IIb trial of recombinant factor VIIa. Fifteen scans could not be analyzed for technical reasons, but baseline characteristics were not statistically significantly different. Hounsfield unit histograms for each ICH were generated. Analyzed qCTD parameters included the following: mean, SD, coefficient of variation, skewness (distribution asymmetry), and kurtosis ("peakedness" versus "flatness"). These densitometry parameters were examined in statistical models accounting for baseline volume and time-to-scan.RESULTS:The coefficient of variation of the ICH attenuation was the most significant individual predictor of hematoma growth (adjusted R(2) = 0.107, P = .002), superior to BV (adjusted R(2) = 0.08, P = .006) or TTS (adjusted R(2) = 0.03, P = .05). The most significant combined model incorporated coefficient of variation, BV, and TTS (adjusted R(2) = 0.202, P = .009 for coefficient of variation) compared with BV and TTS alone (adjusted R(2) = 0.115, P < .05). qCTD increased the number of growth predictions within ±1 mL of actual 24-hour growth by up to 47%.CONCLUSIONS:Heterogeneous ICH attenuation on hyperacute (<3 hours) CT imaging is predictive of subsequent hematoma expansion and may reflect an active bleeding process. Further studies are required to determine whether qCTD can be incorporated into standard imaging protocols for predicting ICH growth.
American Journal of Neuroradiology 01/2013; · 3.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Protoplasmic astrocytomas are a poorly recognized and uncommon subtype of astrocytoma. While usually categorized with other low-grade gliomas, there is literature to suggest that protoplasmic astrocytomas have differences in biology compared to other gliomas in this group. This paper presents the MR imaging characteristics of a series of eight protoplasmic astrocytomas.
We retrospectively reviewed MR images and histopathology of eight consecutive cases of histologically proven protoplasmic astrocytomas.
Patients ranged from 17 to 51 years of age with a 5:3 male to female ratio. The tumors were located in the frontal or temporal lobes and tended to be large, well defined, and had a very high signal on T2 (close to cerebrospinal fluid). Generally, a large proportion of the tumor showed substantial signal suppression on T2 fluid-attenuated inversion recovery (FLAIR). Six of the eight lesions also demonstrated a partial or complete rim of reduced apparent diffusion coefficient (ADC) around the T2 FLAIR suppressing portion.
The possibility that a primary cerebral neoplasm represents a protoplasmic astrocytoma should be considered in a patient with a large frontal or temporal tumor that has a very high signal on T2 with a large proportion of the tumor showing substantial T2 FLAIR suppression. A further clue is a partial or complete rim of reduced ADC.
[Show abstract][Hide abstract] ABSTRACT: the Echoplanar Imaging Thrombolytic Evaluation Trial (EPITHET) was a prospective, randomized, double-blinded, placebo-controlled, phase II trial of alteplase between 3 and 6 hours after stroke onset. The primary outcome of infarct growth attenuation on MRI with alteplase in mismatch patients was negative when mismatch volumes were assessed volumetrically, without coregistration, which underestimates mismatch volumes. We hypothesized that assessing the extent of mismatch by coregistration of perfusion and diffusion MRI maps may more accurately allow the effects of alteplase vs placebo to be evaluated.
patients were classified as having mismatch if perfusion-weighted imaging divided by coregistered diffusion-weighted imaging volume ratio was >1.2 and total coregistered mismatch volume was ≥ 10 mL. The primary outcome was a comparison of infarct growth in alteplase vs placebo patients with coregistered mismatch.
of 99 patients with baseline diffusion-weighted imaging and perfusion-weighted imaging, coregistration of both images was possible in 95 patients. Coregistered mismatch was present in 93% (88/95) compared to 85% (81/95) with standard volumetric mismatch. In the coregistered mismatch patients, of whom 45 received alteplase and 43 received placebo, the primary outcome measure of geometric mean infarct growth was significantly attenuated by a ratio of 0.58 with alteplase compared to placebo (1.02 vs 1.77; 95% CI, 0.33-0.99; P=0.0459).
when using coregistration techniques to determine the presence of mismatch at study entry, alteplase significantly attenuated infarct growth. This highlights the necessity for a randomized, placebo-controlled, phase III clinical trial of alteplase using penumbral selection beyond 3 hours.
[Show abstract][Hide abstract] ABSTRACT: Transient ischemic attack (TIA) has recently been redefined to incorporate the latest clinical and neuroimaging information that has shed new light on TIA pathophysiology. Patients suffering from TIA are at a substantial risk of subsequent stroke, but quantifying this risk is difficult as TIA patients are a heterogeneous population and there are multiple TIA mimics. Clinical scores for prediction of stroke risk are principally based on patient history and potentially understate actual risk. Magnetic resonance imaging (MRI), in particular diffusion-weighted imaging (DWI) performed in the first days following TIA, reveals relevant focal ischemic abnormalities in 21-68% of patients. These lesions predict stroke recurrence, functional dependence and subsequent vascular events. Adding imaging information to clinical scores improves prediction of stroke risk following TIA. Alongside clinical judgement, use of MRI has the potential to change the management of TIA patients and is the imaging modality of choice for this condition.
Journal of Clinical Neuroscience 09/2010; 17(9):1105-10. · 1.32 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background Stents are an alternative treatment to carotid endarterectomy for symptomatic carotid stenosis, but previous trials have not established equivalent safety and efficacy. We compared the safety of carotid artery stenting with that of carotid endarterectomy. Methods The International Carotid Stenting Study (ICSS) is a multicentre, international, randomised controlled trial with blinded adjudication of outcomes. Patients with recently symptomatic carotid artery stenosis were randomly assigned in a 1:1 ratio to receive carotid artery stenting or carotid endarterectomy. Randomisation was by telephone call or fax to a central computerised service and was stratified by centre with minimisation for sex, age, contralateral occlusion, and side of the randomised artery. Patients and investigators were not masked to treatment assignment. Patients were followed up by independent clinicians not directly involved in delivering the randomised treatment. The primary outcome measure of the trial is the 3-year rate of fatal or disabling stroke in any territory, which has not been analysed yet. The main outcome measure for the interim safety analysis was the 120-day rate of stroke, death, or procedural myocardial infarction. Analysis was by intention to treat (ITT). This study is registered, number ISRCTN25337470. Findings The trial enrolled 1713 patients (stenting group, n=855; endarterectomy group, n=858). Two patients in the stenting group and one in the endarterectomy group withdrew immediately after randomisation, and were not included in the ITT analysis. Between randomisation and 120 days, there were 34 (Kaplan-Meier estimate 4.0%) events of disabling stroke or death in the stenting group compared with 27 (3.2%) events in the endarterectomy group (hazard ratio [HR] 1.28, 95% CI 0.77-2.11). The incidence of stroke, death, or procedural myocardial infarction was 8.5% in the stenting group compared with 5.2% in the endarterectomy group (72 vs 44 events; HR 1.69, 1.16-2.45, p=0.006), Risks of any stroke (65 vs 35 events; HR 1.92, 1.27-2.89) and all-cause death (19 vs seven events; HR 2.76, 1.16-6.56) were higher in the stenting group than in the endarterectomy group. Three procedural myocardial infarctions were recorded in the stenting group, all of which were fatal, compared with four, all non-fatal, in the endarterectomy group. There was one event of cranial nerve palsy in the stenting group compared with 45 in the endarterectomy group. There were also fewer haematomas of any severity in the stenting group than in the endarterectomy group (31 vs 50 events; p=0.0197). Interpretation Completion of long-term follow-up is needed to establish the efficacy of carotid artery stenting compared with endarterectomy. In the meantime, carotid endarterectomy should remain the treatment of choice for patients suitable for surgery
The Lancet 01/2010; 375:985. · 39.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Reliable predictors of hemorrhagic transformation (HT) after stroke thrombolysis have not been identified. We analyzed hemorrhage in a randomized trial of tissue plasminogen activator (t-PA) vs placebo in ischemic stroke patients. We hypothesized that acute diffusion-weighted imaging (DWI) lesion volumes would be larger and blood pressures would be higher in patients with HT.
HT was assessed 2 to 5 days after treatment in 97 patients. Hemorrhage was assessed by using susceptibility-weighted imaging sequences and was classified as petechial hemorrhagic infarction (HI) or parenchymal hematoma (PH).
PH was more frequent in t-PA- (11/49) than in placebo- (4/48) treated patients (P=0.049). Patients with PH had larger DWI lesion volumes (63.1+/-56.1 mL) than did those without HT (27.6+/-39.0 mL, P=0.033). There were no differences in baseline systolic blood pressure (SBP) between patients with and without hemorrhage. Weighted average SBP 24 hours after treatment was higher in patients with PH (159.4+/-18.8 mL, P<0.011) relative to those without HT (143.1+/-20.0 mL). Multinomial logistic regression indicated that PH was predicted by DWI lesion volume (odds ratio=1.16 per 10 mL; 95% CI, 1.03 to 1.30), atrial fibrillation (odds ratio=9.33; 95% CI, 2.30 to 37.94), and 24-hour weighted average SBP (odds ratio=1.59 per 10 mm Hg; 95% CI, 1.14 to 2.23).
Pretreatment DWI lesion volume and postthrombolysis BP are both predictive of HT. Consideration should be given to excluding patients with very large baseline DWI volumes from t-PA therapy and to more stringent BP control after stroke thrombolysis.
[Show abstract][Hide abstract] ABSTRACT: Intracerebral hemorrhage (ICH) growth predicts mortality and functional outcome. We hypothesized that irregular hematoma shape and density heterogeneity, reflecting active, multifocal bleeding or a variable bleeding time course, would predict ICH growth.
Three raters examined baseline sub-3-hour CT brain scans of 90 patients in the placebo arm of a Phase IIb trial of recombinant activated Factor VII in ICH. Each rater, blinded to growth data, independently applied novel 5-point categorical scales of density and shape to randomly presented baseline CT images of ICH. Density and shape were defined as either homogeneous/regular (Category 1 to 2) or heterogeneous/irregular (Category 3 to 5). Within- and between-rater reliability was determined for these scales. Growth was assessed as a continuous variable and using 3 binary definitions: (1) any ICH growth; (2) >or=33% or >or=12.5 mL ICH growth; and (3) radial growth >1 mm between baseline and 24-hour CT scan. Patients were divided into tertiles of baseline ICH volume: "small" (0 to 10 mL), "medium" (10 to 25 mL), and "large" (25 to 106 mL).
Inter- and intrarater agreements for the novel scales exceeded 85% (+/-1 category). Median growth was significantly higher in the large-volume group compared with the small group (P<0.001) and in heterogeneous compared with homogeneous ICH (P=0.008). Median growth trended higher in irregular ICHs compared with regular ICHs (P=0.084). Small ICHs were more regularly shaped (43%) than medium (17%) and large (3%) ICHs (P<0.001). Small ICHs were more homogeneous (73%) compared with medium (37%) and large (17%) ICHs (P<0.001). Adjusting for baseline ICH volume and time to scan, density heterogeneity, but not shape irregularity, independently predicted ICH growth (P=0.046) on a continuous growth scale.
Large ICHs were significantly more irregular in shape, heterogeneous in density, and had greater growth. Density heterogeneity independently predicted ICH growth using some definitions.
[Show abstract][Hide abstract] ABSTRACT: Background
Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disorder characterized by motor, psychiatric, and cognitive dysfunction. One of the main focuses of clinical research now is to define valid and reliable biomarkers of disease onset and progression that can be of use in future treatment trials. Various neuropathological and neuroimaging studies have indicated early involvement of various components of the basal ganglia.
In this study, we examined the sensitivity of three magnetic resonance techniques in detecting basal ganglia pathology. Diffusion tensor imaging (DTI) is an MRI technique that measures indices of passive water diffusion, which is believed to reflect the tissue fiber density, fiber architecture, and uniformity of nerve fiber direction. Proton MRS (1H-MRS) is a non-invasive technique that allows the detection of brain chemicals that contain hydrogen, such as N-Acetyl-aspartate (NAA), choline-containing compounds (CHO), creatine/phosphocreatine (CRE), glutamine, glutamate, myoinositol (mI), and lactate (LAC). Volumetric measures of caudate and putamen can be obtained from structural MRI scans.
We examined 25 HD gene carriers (13 preclinical and 12 early symptomatic) and 20 matched gene negative controls. The three imaging modalities were performed on each subject using a GE Signa 1.5T scanner during one scan session. Six HD gene carriers and two control subjects were scanned twice, two years apart. Clinical measures were also collected.
The H-MRS revealed increased choline/creatine and myoinositol/creatine ratios in the basal ganglia in the symptomatic group and decreased glutamate+glutamine/creatine ratios in the preclinical group. Preliminary DTI analyses suggest reduced anisotropy, measured as fractional anisotropy in the basal ganglia. More detailed DTI results and volumetric data will be presented at the meeting. The sensitivity, limitations of, and relationship between the three MRI imaging modalities in detecting basal ganglia pathology in HD will be discussed. The combination of all three techniques may provide a more powerful tool to predict aspects of the clinical presentation.
[Show abstract][Hide abstract] ABSTRACT: We report the case of a 74-year-old woman who presented with deterioration in gait, short-term memory loss and urinary incontinence. She had a past history of excision of a cervical dermal sinus tract at the age of 5 years. CT scan in 2004 revealed ventriculomegaly and an extremely hypodense ovoid structure lying in the midline low posterior fossa with calcification anteriorly. On MRI, the lesion was hypointense on T1-eighted and hyperintense on T2-weighted images, with incomplete suppression on fluid-attenuated inversion-recovery images and marked restriction on diffusion weighted images. Cerebrospinal fluid isotope study revealed non-communicating hydrocephalus. Posterior fossa crainectomy and removal of the lesion was undertaken. Pathological study revealed a dermoid cyst. Post-operatively, her hydrocephalus persisted and a ventriculo-atrial shunt was inserted with excellent functional recovery.
Journal of Clinical Neuroscience 08/2008; 15(7):835-8. · 1.32 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Whether intravenous tissue plasminogen activator (alteplase) is effective beyond 3 h after onset of acute ischaemic stroke is unclear. We aimed to test whether alteplase given 3-6 h after stroke onset promotes reperfusion and attenuates infarct growth in patients who have a mismatch in perfusion-weighted MRI (PWI) and diffusion-weighted MRI (DWI).
We prospectively and randomly assigned 101 patients to receive alteplase or placebo 3-6 h after onset of ischaemic stroke. PWI and DWI were done before and 3-5 days after therapy, with T2-weighted MRI at around day 90. The primary endpoint was infarct growth between baseline DWI and the day 90 T2 lesion in mismatch patients. Major secondary endpoints were reperfusion, good neurological outcome, and good functional outcome. Patients, caregivers, and investigators were unaware of treatment allocations. Primary analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT00238537.
We randomly assigned 52 patients to alteplase and 49 patients to placebo. Mean age was 71.6 years, and median score on the National Institutes of Health stroke scale was 13. 85 of 99 (86%) patients had mismatch of PWI and DWI. The geometric mean infarct growth (exponential of the mean log of relative growth) was 1.24 with alteplase and 1.78 with placebo (ratio 0.69, 95% CI 0.38-1.28; Student's t test p=0.239); the median relative infarct growth was 1.18 with alteplase and 1.79 with placebo (ratio 0.66, 0.36-0.92; Wilcoxon's test p=0.054). Reperfusion was more common with alteplase than with placebo and was associated with less infarct growth (p=0.001), better neurological outcome (p<0.0001), and better functional outcome (p=0.010) than was no reperfusion.
Alteplase was non-significantly associated with lower infarct growth and significantly associated with increased reperfusion in patients who had mismatch. Because reperfusion was associated with improved clinical outcomes, phase III trials beyond 3 h after treatment are warranted.
The Lancet Neurology 04/2008; 7(4):299-309. · 21.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: For MR perfusion-diffusion (PWI-DWI) mismatch to become routine in thrombolysis patient selection, rapid and reliable assessment tools are required. We examined interrater variability in PWI/DWI volume measurements and developed a rapid assessment tool based on the Alberta Stroke Program Early CT Scores (ASPECTS) system.
DWI and PWI were performed in 35 patients with stroke <6 hours after symptom onset. DWI lesion and PWI (time to peak) volumes were measured with planimetric techniques by 4 raters and the 95% limits of agreement calculated. ASPECT scores were assessed separately by 4 investigators (2 experienced and 2 inexperienced) for DWI (MR DWI scores) and PWI (MR time to peak scores). MR mismatch scores were calculated as MR DWI-MR time to peak scores.
Interobserver variability was much greater for PWI (95% limit of agreement=+/-72.3 mL) than for DWI (95% limit of agreement=+/-12.6 mL). A semiautomated PWI volume (time to peak+2 s) was therefore used to calculate mismatch volume. MR mismatch scores >or=2 predicted 20% PWI-DWI mismatch by volume with mean 78% sensitivity (range, 72% to 84%) and 88% specificity (range, 83% to 90%). There was excellent agreement on mismatch classification using MR mismatch scores between experienced raters (weighted kappa scores of 0.94) with agreement in 34 of 35 cases. Agreement was less consistent between inexperienced raters (weighted kappa=0.49, 28 of 35 cases).
Variability in planimetric mismatch measurements arises primarily from differences in PWI volume assessment. High specificity and interrater reliability may make MR mismatch scores an ideal rapid screening tool for potential thrombolysis patients.
[Show abstract][Hide abstract] ABSTRACT: The value of magnetic resonance imaging (MRI) in investigation of patients with late-onset epilepsy has not been studied systematically. We evaluated prospectively the usefulness of MRI in 50 patients with late-onset epilepsy in whom a computed tomography (CT) scan was normal (32), did not allow a definitive diagnosis to be made (12), or showed irrelevant lesions (6). Patients were assessed clinically and had an EEG, and CT and MRI scans were reported by one neuroradiologist blinded to clinical and laboratory data. Of the 32 patients with a normal CT scan, MRI was normal in 20, showed irrelevant ischemic lesions in 8, and showed the cause of seizures in 4 patients. Of the 12 patients with nondiagnostic CT, MRI clarified the diagnosis in 5 and was normal in 2 patients. In 6 patients, both scans showed irrelevant ischemic lesions, and in 1 patient MRI showed a relevant additional lesion. The incidence of MRI-detected white matter ischemic lesions was no greater than in an age- and sex-matched group of subjects without seizures. MRI was diagnostic in 32% of the patients with partial seizures and/or focal EEG findings, as compared with 0% of patients without focal features (p < 0.01). We conclude that MRI is useful in investigation of patients with late-onset epilepsy with focal features.RÉSUMÉĽapport de ľimagerie par résonance magnélique (IRM) dans le bilan de patients présentant une épilepsie tardive, n'a pas étéétudié de façon systématique. Dans cette étude, les auteurs ont évalué de façon pospective ľutilityé de ľIRM chez 50 patients présentant une épilepsie tardive, chez lesquels le scanner cérebral avait été normal (32), n'a pas permis ďétablir un diagnostic precis (12) ou a mis en évidence des lésions sans rapport avec ľépilepsie (6). Les patients ont bénéficéďun bilan clinique, électroencéphalographique (EEG), le scanner et ľIRM ont étéévalués par un neuroradiologiste qui n'était pas au courant des données cliniques ou de laboratoire. Parmi les 32 patients qui avaient un scanner normal, ľIRM était normale chez 20, a mis en évidence des lésions ischémiques sans rapport avec ľépilepsie chez 8, et a mis en évidence ľétiologie de ľepilepsie chez 4 patients. Chez les 12 patients pour lesquels le scanner n'avait pas eu de valeur diagnostique, ľIRM a permis de clarifier le diagnostic pour 5, elle est restée normale dans 2 cas. Chez 6 patients, ľIRM et le scanner ont tous deux mis en évidence des lésions ischémiques sans rapport avec ľépilepsie, chez 1 patient ľIRM a permis de constater une lésion supplémental significative pour ľépilepsie, Ľincidence des lésions ischémiques de la substance blanche détectées par ľIRM n'a pas été supérieure à celle constatée dans un groupe de sujets non épileptiques appariés pour le sexe et ľâge. ĽIRM a eu un apport diagnostique chez 32% des patients présentant des crises partielles et/ou des anomalies focales àľEEG, contre 0% des patients n'ayant pas présenté de symptomatologie partielle (p < 0.01). Les auteurs concluent que ľIRM est utile dans le bilan de patients présentant une épilepsie tardive avec des caractéristiques focales.RESUMENNo se ha estudiado systemáticamente el valor de la resonancia magnética (MR) en la investigación de enfermos con epilepsyía de comienzo tardío. Este estudio valora prospectivamente la utilizatiioAn de la MR en 50 enfermos con epilepsyía tardía en los cuales la tomografía computarizada (CT) fue normal (32), no permitió un diagnóstico definitivo (12) o reveló lesiones irrelevantes (86). Los pacientes fueron estudiados clínicamente y con un electroencefalograma (EEG). La CT y MR fueron informadas por un neurorradiólogo que no conocía los datos clinicos o de laboratory. De los 32 enfermos con una CT normal, la MR fue normal en 20, mostró lesiones isquémicas irrelevantes en 8 y reveló la causa de los ataques en 4 pacientes. De los 12 pacientes con un CT no-diagnóstico, la MR aclaró el diagnóstico en 5 y fue normal en 2 casos. En 6 enfermos ambas técnicas mostraron lesions isquémicas irrelevantes y en un enfermo la MR detectó una lesión adicional relevante. La incidencia de las lesiones isquémicas de sustancia blanca descubiertas con la MR no fue mayor que en un grupo de edad y sexo semejantes, sin ataques. La MR fue diagnóstica en el 32% de los enfermos con crisis parciales y/o con hallazgos focales en el EEG. No fue diagnóstica (0%) en enfermos sin datos focales (p < 0.01). Se concluye que la MR es útil en la investigación de enfermos con epilepsyía tardía con hallazgos focales.ZUSAMMENFASSUNGDer Wert der Magnetresonanz-Tomographie (MRI) für die Diagnostic von Patienten mit spät einsetzender Epilepsie wurde bisher noch nicht systematise!] untersucht. Die Studie wertet prospektiv den Nutzen des MRI bei 50 Patienten mit spät einsetzender Epilepsie aus. Bei 32 Patienten fiel das CT normal aus, erlaubte keine entgültige Diagnose (12) oder entdeckte nur unbedeutende Laesionen (6). Die Patienten wurden klinisch und elektroenzephalographisch untersucht, CT und MRI wurden “blind” durch einen Neuroradiologen befundet. Von den 32 Patienten mit normalem CT boten 20 auch ein normales MRI. Unbedeutende ischämische Laesionen fanden sich bei 8 Patienten und eine Ursache für die Anfälle bei 4 Patienten. Bei den 12 Patienten ohne entgültige CT-Diagnose erhellte das NMR eine Diagnose in 5 Fällen. In 2 Fällen war es normal. Bei 6 Patienten zeigten beide Untersuchungen unbedeutende ischämische Laesionen und bei 1 Patient fand sich eine zusätzliche relevante Schädigung. Die Häufigkeit der durch das MRI ischaumischen Laesionen in der Weißen Substanz war nicht größer als in einer alters–und geschlechts–gemat chten Gruppe von Personen ohne Anfälle. In 32% der Patienten mit Partial-Anfällen oder fokalen EEG-Befunden konnte anhand des MRI eine Diagnose gestellt wer-den, verglichen mit 0% bei fehlenden fokalen Zeichen (p < 0.01). Daraus wird geschlossen, daß das MRI für die Untersuchung von Patienten mit Spät-Epilepsie und fokalen Zeichen sinnvoll ist.
[Show abstract][Hide abstract] ABSTRACT: To undertake a pilot study to assess whether magnetic resonance (MR) contrast-enhanced perfusion imaging (CEPI) and diffusion-weighted imaging (DWI) provide lateralizing information in medically refractory temporal lobe epilepsy (TLE),and to compare this to standard quantitative hippocampal assessments (volumetric measurements and T2 relaxometry).
Ten patients with 'non-lesional' TLE and 10 control subjects were studied. Quantification of the relative cerebral blood flow (rCBF) and apparent diffusion coefficient (ADC) was performed for the hippocampal regions. The ratios of the ipsilateral-to-contralateral side (to the EEG lateralization) were compared with the side-to-side ratios in the controls.
Six patients (60%) had an ADC ratio outside the control range (the larger ADC ipsilateral to the EEG lateralization in all cases). The CBF ratios were outside the control range in all eight patients (100%) in whom CEPI was performed (the lower value ipsilateral to the EEG lateralization in all cases). The magnitude of the hippocampal volume (HV) ratios showed no significant correlation with the magnitude of the ADC ratios (R=-0.03, p=0.93) or CBF ratios (R=0.36, p=0.39). There was a closer relationship with the T2 relaxometry ratios, but this was also not significant (R=-0.40, p=0.32; R=0.58, p=0.08).
DWI and CEPI show potential as reliable tools for the lateralization of non-lesional TLE. Further studies with larger numbers are necessary to determine whether these techniques provide independent data to established MR quantitative measures.
Journal of Clinical Neuroscience 10/2007; 14(9):841-9. · 1.32 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The Alberta Stroke Program Early CT Score (ASPECTS) is a validated method of assessing parenchymal ischemic changes, including focal swelling and hypoattenuation. The hypothesis that these signs result from different pathophysiological processes was tested by comparing CT with diffusion and perfusion- weighted MRI.
MRI and CT were performed, within 2 hours of each other, in 30 ischemic stroke patients <17 hours after symptom onset. Relative apparent diffusion coefficient, relative cerebral blood flow, and relative cerebral blood volume were calculated for individual cortical ASPECTS regions. Regional infarction was assessed on days 3 to 5.
Isolated focal swelling was seen in 25 ASPECTS cortical regions from 6 patients. Cortical hypoattenuation was observed in 25 regions from 11 patients. Median relative apparent diffusion coefficient was significantly lower in hypoattenuated regions (0.84; interquartile range, 0.66 to 0.91) relative to those with focal swelling (0.97; interquartile range, 0.91 to 1.01; P<0.001). Median relative cerebral blood flow in focal swelling regions (81.0%; interquartile range, 70.4 to 93.0) was similar to that of tissue that appeared normal on CT (71.8%; interquartile range, 47.1 to 94.5). In hypoattenuated regions, relative cerebral blood flow was significantly decreased (37.0%; interquartile range, 25.6 to 70.2; P=0.002). Median relative cerebral blood volume was increased (121.1%; interquartile range, 112.0 to 130.3) in focal swelling regions, relative to normal-appearing tissue (94.7%; interquartile range, 62.0 to 114.6; P<0.001), but decreased in hypoattenuated regions (58.9%; interquartile range, 47.5 to 92.7; P=0.012). Infarction occurred in all hypoattenuated regions, but only in 32% of those with focal swelling.
Elevated relative cerebral blood volume and normal relative apparent diffusion coefficient in ASPECTS regions with focal swelling on CT is consistent with penumbral tissue. Isolated focal swelling is not always associated with infarction. These results support removal of focal swelling from the ASPECTS system.