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Objective: To demonstrate the accuracy of magnetic resonance tractograpghy (MRT) in localizing the cortical spinal tract (CST) close to brain tumours by using intraoperative electric subcortical stimulation.Methods: Nine patients with intra-axial brain tumours underwent neurosurgery. Planning was based on analysis of the course of streamlines compatible with the CST. After tumour removal, intraoperative MRT was reacquired. Sites at various distance from the CST were repeatedly stimulated to assess whether registered motor evoked potential (MEP) could be elicited. All patients were assessed clinically both pre- and postoperatively.Results: The motor function was preserved in all patients. In all patients intraoperative MRT demonstrated shift of the bundle position caused by the surgical procedure. The distance between the estimated intraoperative CST and the point of elicited MEP was 1 cm or less in all nine patients. At distances greater than 2 cm, no patient reported positive MEP.Conclusion: Intraoperative MRT is a reliable technique for localization of CST. In all patients MEP were elicited by direct subcortical electrical stimulation at a distance below 1 cm from the CST as represented by MRT. Brain shifting might impact this evaluation since CST position may change during surgery in the range of 8 mm. [ABSTRACT FROM AUTHOR]

The purposes of this study were (1) to evaluate the possible identification of trajectories of fibre tracts, (2) to examine the useful of a neuronavigation system for presurgical planning, (3) to assess pre- and post-surgery patients' clinical condition and (4) to evaluate the impact of this information on surgical planning and procedure. Twenty-eight right-handed patients were prospectively and consecutively studied. All the patients were clinically assessed by a neurologist in both pre- and postsurgical phases. Separately the pyramidal tract, optic radiation and arcuate fasciculus were reconstructed. The trajectories were considered suitable for surgical planning if there were no interruptions of any of the layers at the level of the lesion. Dedicated software 'merged' the acquired images with the tractographic processing, and the whole dataset was sent to the neuronavigation system. The assessment of the 37 visualised trajectories close to the tumour resulted in a modification of the surgical approach to corticotomy in six patients (21%); the impact on the definition of the resection margins during surgery was 64%(18 cases). The overall impact percentage on the surgical procedure was 82%. In 27 cases, the symptoms had not changed. MR-tractography provides the neurosurgeon with a new anatomical view that has an impact on the surgical resection planning for brain neoplasms. [ABSTRACT FROM AUTHOR]

Objective: To assess what kind of information MR examination in flexed and extended positions provides in Down syndrome subjects with suspected cranio-cervical instability., Methods: Between 2005 and 2008, 35 subjects with DS were recruited in the study. Ethics committee approval was granted and a signed informed consent was obtained from the parents. All the subjects were affected by hypotonic status and ligament laxity established by clinical evaluation, but were asymptomatic about focal neurological symptoms due to medullar damage caused by cranio-cervical instability. Each patient underwent lateral supine radiographs and MR imaging in the neutral, active flexed and extended positions. For evaluating the atlanto-axial and atlanto-occipital joint stability, multiple measurements were calculated., Results: A significant reduction of anterior subarachnoid space in flexed position was evident in DS subjects compared to healthy controls in neutral and flexed positions. Both, space available for cord and ligamentous thickness showed significant differences between DS subjects and healthy controls. In DS subjects with occipito-cervical instability, the anterior subarachnoidal space reduction was significantly reduced in flexed position., Conclusions: In DS subjects with asymptomatic cranio-cervical instability, anterior subarachnoidal evaluation and ligamentous status could add new information about the risk of spinal cord damage.

Purpose: The aim of this study was to verify the sensitivity and specificity of the hyperdense middle cerebral artery sign (HMCAS) obtained by multidetector computed tomography (CT) in predicting acute stroke, using diffusion-weighted (DW) magnetic resonance imaging (MRI) as a reference. The location of the HMCAS, the extension of the ischaemic lesion and its prognostic value were also assessed., Materials and Methods: The CT examinations of 654 patients with symptoms related to acute cerebral stroke were retrospectively reviewed. DW-MRI confirmed recent stroke in 175 patients. Two expert neuroradiologists analysed the CT examinations of these patients in four phases. Sensitivity, specificity and interobserver reliability was evaluated. Patients were divided into three groups according to the HMCAS site (M1-M2-M3) and the Alberta Stroke Program Early CT Score (ASPECTS) on DW-MRI was calculated. The ASPECTS average score was correlated with the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS) at 3 months., Results: In 41 patients, the presence of HMCAS was confirmed (71 % sensitivity; 100 % specificity; Interobserver reliability k, 84 %). An inverse correlation was found by comparing the ASPECTS and NIHSS scores (Rsq = -0.206). After logistic regression analysis, HMCAS was found to be independently associated with a poor outcome (mRS >2) at 3 months after adjusting for age, NIHSS on admission, risk factors and aetiology of stroke., Conclusions: Our study demonstrated that HMCAS obtained with multidetector CT can be detected in more than 70 % of patients with large acute ischaemic lesion and it is an unfavourable prognostic sign.

Objective: To evaluate whether apparent diffusion coefficient (ADC) values can predict the status of MGMT of glioblastoma multiforme (GBM) and correlate with overall survival (OS) and progression-free survival (PFS)., Methods: This retrospective study included 47 patients with pathologically proven glioblastoma. All of them underwent MR DWI study before surgery (mean time 1 week) and the status of methylguanine-DNA-methyltransferase (MGMT) promoter methylation was searched for. Minimum apparent diffusion coefficient (ADC) values were evaluated. OS and PSF parameters were calculated, and Student's t-test, Kaplan-Meier curves, linear and Cox regression were performed., Results: Twenty-five patients showed positive methylation of the MGMT promoter. Patients showing MGMT promoter methylation had higher minimum ADC values, and they survived longer than those without MGMT promoter methylation. The median ADCmin value of 0.80 represents the cutoff value able to distinguish between methylated and un-methylated patients. Patients showing minimum ADC values higher than 0.80 survived longer than patients with minimum ADC values lower than 0.80. A linear correlation between minimum ADC values vs. the OS and PFS was observed., Conclusions: Minimum ADC values in glioblastoma multiforme could be used as a preoperative parameter to estimate the status of MGMT promoter methylation and the survival of patients.

Ventricular dyssynchrony significantly impairs cardiac performance. However, the independent role of interventricular dyssynchrony (interVD) and intraventricular dyssynchrony (intraVD) in the development of abnormalities of systolic and diastolic performance is unclear. Cardiac magnetic resonance imaging was performed in 39 patients with left bundle branch block and 13 healthy patients. Structural and functional parameters of the left ventricle and degrees of interVD and intraVD were measured. We found that interVD was inversely correlated with left ventricular (LV) ejection fraction (r = -0.8, p <0.0001) and positively correlated with LV end-diastolic volume (r = 0.4, p <0.01), LV end-systolic volume (r = 0.6, p <0.0001), and LV mass (r = 0.4, p <0.01), thus indicating that interVD significantly affects systolic function and favors ventricular remodeling. Multivariate analysis further confirmed that interVD was an independent predictor of systolic dysfunction. Interestingly, we found that interVD was not associated with abnormalities of diastolic performance. Conversely, we found that intraVD significantly impaired diastolic function, whereas it had no effect on systolic function. IntraVD was inversely correlated with peak filling rate (r = -0.7, p <0.0001) and 1/2 filling fraction (r = 0.4, p = 0.04) and positively correlated with time to peak filling rate (r = 0.6, p <0.0001), validated parameters of diastolic function. Multivariate analysis confirmed that intraVD was an independent predictor of diastolic dysfunction. In conclusion, our study suggests that the 2 components of ventricular dyssynchrony differently affect cardiac performance. If confirmed in prospective studies, our results may help to predict the prognosis of patients with left bundle branch block and different degrees of interVD and intraVD, particularly those subjects undergoing cardiac resynchronization therapy., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Magnetic resonance imaging (MRI) with a dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) sequence to study brain tumours provides information on the haemodynamic characteristics of the neoplastic tissue. Brain perfusion maps and calculation of perfusion parameters, such as relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV) and mean transit time (MTT) allow assessment of vascularity and angiogenesis within tumours of the central nervous system (CNS), thus providing additional information to conventional MRI sequences. Although DSC-PWI has long been used, its clinical use in the study of brain tumours in daily clinical practice is still to be defined. The aim of this review was to analyse the application of perfusion MRI in the study of brain tumours by summarising our personal experience and the main results reported in the literature.

We describe a case of asymmetric PRES due to the presence of hyperplastic anterior choroidal artery (AChA) in a man affected by sever hypertension. Posterior reversible encephalopathy syndrome (PRES) has become synonymous with a unique pattern of brain vasogenic edema and predominates in the parietal and occipital regions, accompanied by clinical neurological alterations. Sever hypertension is a risk factor that exceeds the limits of brain autoregulation, leading to breakthrough brain edema. In our knowledge this is the first case reported in literature, in which a similar vascular abnormality is linked to a PRES syndrome., (© The Author(s) 2010. This article is published with open access at Springerlink.com)

The most frequent type of Krabbe disease has an infantile onset. Unusual slowly progressive adult forms have also been described. We described a different involvement of white matter tracts where magnetic resonance signal alterations were evident in a case of a patient affected by late-onset form of disease.

Posterior cerebral artery (PCA) territory infarcts account for only 5-10% of all infarcts in stroke registries. Moreover, the clinical features and etiology of such infarcts have not been studied as extensively as those in other vascular territories.We describe two patients with recurrent episodes of visual symptoms and headache due to probable transitory PCA vasospasm. MR angiography in the acute phase revealed incomplete visualization of PCA, conventional MRI showed mild T2 signal alterations and MR perfusion showed the presence of marked hypoperfusion in the same regions. Diffusion weighted MR images were normal. All these findings resolved after therapy. These cases suggest that reversible signal alterations associated with reversible vessel and perfusion abnormalities may be observed in patients with visual symptoms and headache. Normal DWI-MR may help distinguish these patients from those affected by non-reversible ischemic attacks.

We describe a 32-year-old woman who presented with progressive dorsal back pain. Neither sensory nor motor deficit was reported. Magnetic resonance imaging (MRI) of the dorsal spine revealed a primary intradural extramedullary lesion with severe spinal cord compression. No other lesion was found in the central nervous system. During surgery an intradural extramedullary tumor was found without medullary infiltration and a total removal was achieved under microscopic guidance. The histological diagnosis revealed a benign extramedullary ependymoma. The patient recovery completely after surgery and at a follow-up of 24 months MRI showed no evidence of tumor recurrence. Ependymoma should be taken in account in the differential diagnosis on intradural extramedullary tumours.

Whether fractional anisotropy (FA), apparent diffusion coefficient (ADC), and fiber density index (FDi) values differ in the white matter close to glioblastomas of both symptomatic and asymptomatic patients was investigated. Twenty patients with glioblastomas underwent magnetic resonance imaging study. The FDi, FA and ADC values were calculated in areas of white matter in close proximity to the tumor (perWM) and encompassing fibers of cortico-spinal tract and in the contralateral normal-appearing white matter (nWM). The clinical compromise of the cortico-spinal tract was graded using Brunnstrom's criteria. FA and FDi were significantly decreased and ADC increased in perWM compared with the contralateral. Mean FDi, FA, and ADC values comparing perWM and nWM in symptomatic patients showed similar differences. Comparing the perWM of symptomatic and asymptomatic patients, mean FDi and ADC values were lower in symptomatic patients than in asymptomatic ones. A positive correlation was found between the clinical score (CS) and, separately, FDi, FA and ADC per WM values. In a multiple stepwise regression among the same factors, only the ADC of perWM values showed a positive correlation with the CS. An increased ADC plays a major role in reducing the number of fibers (reduced FDi) in symptomatic patients.

Purpose: This study was conducted to assess the possibility of identifying precise white matter tracts situated in proximity to intracranial tumours, to define the anatomical and topographical relations between the same white matter tracts and the tumour, to verify the possibility of integrating tractographic images in the context of a package of three-dimensional anatomical images to send to the neuronavigation system, to assess the impact of this information on surgical planning, and to analyse, both pre-and postoperatively, the patient's clinical conditions as an index of the functional integrity of the fibres themselves., Materials and Methods: Twenty-five patients underwent diffusion tensor study prior to neurosurgery. With the use of dedicated software, relative colour maps were obtained and the trajectories of the white matter tracts adjacent to the tumour were reconstructed in three dimensions. These were then processed for preoperative planning. Planning, which was performed with the neuronavigator, was based on analysis of the location of the course of the main white matter tracts adjacent to the lesion (pyramidal tract, optic radiation and arcuate fasciculus). Two neurosurgeons were asked whether the tractography images had modified the access and/or intraoperative approach to the tumour. All patients were clinically assessed both pre-and postoperatively 1 month after the procedure to define the presence of symptoms related to the involvement of the white matter tracts studied and therefore to assess the integrity of the fibres after the operation., Results: In one patient, the tumour was situated away from all the tracts studied and did not compress them in any way. Overall, 40/75 tracts studied had no anatomical relation with the tumour, were not displaced by the tumour or could not be visualised in their entire course. Analysis of the remaining 35 white matter tracts led to an a priori change in the surgical approach for corticotomy in four patients (16%), with no disagreement between the two neurosurgeons and an impact on the extent of resection during surgery in 17 (68%), thus an overall impact on the surgical procedure in 80% of cases. Eight patients showed no symptoms related to the involvement of the white matter tracts studied. In the remaining 17 patients, the symptoms were related to involvement of the pyramidal tract, arcuate fasciculus or optic radiation. At 1-month follow-up, one previously asymptomatic patient reported a speech disorder (transcortical sensory dysphasia); in the remaining 24, symptoms remained unchanged, with a tendency to improvement in 14/17 with symptoms related to involvement of white matter tracts studied., Conclusions: Magnetic resonance (MR) tractography offers the neurosurgeon an anatomical panoramic view that can improve surgical planning for the resection of intracranial tumours. Despite the high incidence of cases in which the lesion is responsible for changes that hinder the reconstruction of white matter tracts, the technique can change the surgical approach for corticotomy, defines the extent of resection and leads to some change in the procedure in 80% of cases. The improvement of pre-existing symptoms and the absence of new symptoms in the postoperative phase, in our opinion, confirms the value of the technique.

Sporadic Creutzfeldt-Jacob disease (CJD) is a transmissible, progressive, fatal spongiform encephalopathy. Routine MR imaging sequences may show abnormalities in the basal ganglia and cerebral cortex. Recently, several reports claimed that diffusion weighted MRI (DWI) could demonstrate early brain lesions in CJD patients when conventional MR images are normal on T2-weighted sequences. We evaluated the usefulness of DWI, perfusion-weighted MRI (PWI) and spectroscopy to confirm the clinical diagnosis and assess lesion progression in two patients with suspected CJD. We noted a diffuse hypoperfusion in the basal ganglia where ADC values were reduced but spectroscopy values were normal. A strong hypoperfusion was observed in the right head of the caudate nucleus in patient n° 2 where spectroscopy values were abnormal. A typical distribution of hypoperfusion followed the posterior progression of disease. We suggest the hypoperfusion in the areas presenting restricted diffusion probably reflects spongiform degeneration and moderate mass effects from cytotoxic edema.

Assessment was made of the cerebral vascular haemodynamic parameters in patients with a high-flow extra-intracranial (EC-IC) bypass performed for therapeutic occlusion of the internal carotid artery (ICA). Sixteen patients with ICA occlusion and EC-IC bypass (time interval from surgery 1-6 years) underwent MRI. Perfusion-weighted magnetic resonance imaging (PW-MRI) sequences were performed without the use of an arterial input function. The relative cerebral blood volume (rCBV), mean transit time (MTT) and relative cerebral blood flow (rCBF) were evaluated in all patients at the level of the basal ganglia, centrum semiovale and cortex in both hemispheres. Statistically significant differences (P<0.005) were observed in the haemodynamic parameters, indicating increased rCBV in the basal ganglia and decreased rCBF and rCBV in the cortex of the hemisphere supplied by the graft with respect to the contralateral. Patients with occlusion of the ICA and high flow EC-IC bypass do have altered vascular haemodynamic status between the hemispheres. In particular, rCBF is impaired in the surgical hemisphere at the level of the cortex. These patients should be followed-up to rule out chronic ischemia.

Parasagittal meningiomas (PSM) may pose a difficult surgical challenge since venous patency and collateral anastomoses have to be clearly defined for correct surgical planning. The aim of this study was to assess the diagnostic value of contrast-enhanced (CE) magnetic resonance venography (MRV) in the preoperative evaluation of venous infiltration and collateral venous anastomoses in patients with PSM. CE-MRV was compared with phase-contrast (PC) magnetic resonance (MR) angiography, conventional angiography (when available), and surgery as a reference. Twenty-three patients undergoing surgery for meningiomas located adjacent to the superior sagittal sinus were prospectively evaluated. All the patients underwent both conventional MR examination and MRV. This was performed by means of PC and CE techniques. Both sets of angiograms (CE and PC) were evaluated by two expert neuroradiologists to assess (1) patency of the sinus (patent/occluded), (2) the extent of occlusion (in centimeters), and (3) the number of collateral anastomoses close to the insertion of the meningioma. Eight patients underwent digital subtraction angiography (DSA). All patients were operated on, and intraoperative findings were taken as the gold standard to evaluate the diagnostic value of MRA techniques. PC-MRV showed a flow void inside the sinus compatible with its occlusion in 15 cases, whereas CE-MRV showed the sinus to be occluded in five cases. CE-MRV data were confirmed by surgery, showing five patients to have an occlusion of the superior sagittal sinus. The PC-MRV sensitivity was thus 100% with a specificity of 50%. In those cases in which both MRV techniques documented occlusion of the sinus, the extent of occlusion was overestimated by PC compared with CE and surgery. CE-MRV depicted 87% of collateral venous anastomoses close to the meningioma as subsequently confirmed by surgery, while PC showed 58%. In the preoperative planning for patients with meningiomas located close to a venous sinus, CE-MRV provides additional and more reliable information concerning venous infiltration and the presence of collateral anastomoses compared with PC sequences.

B.D. is a 48-year-old professional woman. She has been suffering for migraine since she was 28, but she did not have serious problems until last year, when headache episodes became more frequent and it was necessary an admission to emergency room. At the beginning, the events were about 6 per month, lasting from 2 to 4 days, beating and of high intensity together with nausea, vomit, photo and phonophobia and visual area. Looking at the anamnesis, we report a psychiatric treatment since about ten years, because of type II bipolar disorder. In spite of the psychopharmacological treatment, as the patient came in our Regional Headache Center, she talked about 7 events with aura (scintillating scotomas, emianopsia) per month, lasting 2-4 days with photo and phonophobia, nausea, crying crisis, anxiety. Although the neurological examination was normal, the sudden aggravation of pain symptomatology and the unresposiveness to usual painkillers, suggested a cerebral CT and CT-angiography. CT and CT-angiography discovered the presence of an aneurysm of the right middle cerebral artery (MCA) of 4 mm diameter, with parietal irregularities. The patient was operated to reduce the hemorrhagic risk, with a positive result. One year after the operation, the patient reports a decrease of headache events with a frequency of 2 per month, lasting only a few hours, which she can now solve with COXIB.

Introduction: Eclampsia is one of the main causes of Posterior Reversible Encephalopathy Syndrome (PRES) a recent clinico-neuroradiological entity represented by characteristic MR findings of a symmetric bilateral subcortical/cortical hyperintensity in T2-weighted images, more often in parieto-occipital lobes, accompanied by clinical neurological alterations. Neuroradiological and clinical alterations are commonly completely reversible although ischemic evolution has been described. The pathophysiology is still a matter of debate. Specific magnetic resonance (MR) techniques, such as FLAIR (fluid attenuated inversion recovery) and DWI (diffusion weighted images) sequences, have improved the ability to detect subcortical/cortical lesions and helped to clarify the underlying pathophysiological mechanism of cerebrovascular involvement, which results important for an appropriate therapeutic decision., Case Report and Discussion: We report the MR imaging findings of three patients with eclampsia and PRES as well as a careful review of literature.

Among functional magnetic resonance imaging techniques, diffusion-weighted imaging (DWI) plays an important role in the assessment of a wide variety of brain diseases. DWI provides image contrast that depends on the molecular motion of water and it can be easily added to a standard cranial MR examination, with limited increase in time (imaging time ranges from a few seconds to 2 minutes). DWI is particularly sensitive in the detection of acute ischaemic stroke and in monitoring its evolution (also in the light of new therapeutic strategies for early treatment). Diffusion-weighted MR imaging also provides adjunctive information in the differential diagnosis of other brain diseases including neoplasms, intracranial infections, traumatic brain injury and demyelination some of which may manifest with sudden neurological deficits mimicking acute ischaemic stroke.

Summary: Two Landrace Large White swine underwent angiography by the femoral route. In both cases, the superior left renal artery was embolized by injection of 2 ml of Glubran 2((R)), diluted with Lipiodol 1:1 thereby excluding the superior left kidney poles from blood flow. During the follow-up period, neither pig presented any clinical symptom correlated to the embolization procedure. Case 1 was sacrificed after 30 days and case 2 after 60 days. Macroscopic and microscopic analysis was performed in both animals. Long-term follow-up of the two cases after endovascular injection of Glubran 2((R)) showed that the embolization procedure was well-tolerated by the swine in terms of clinical symptoms and histological findings. Arterial occlusion was stable and a reasonable quantity of scar tissue appeared between 30 and 60 days, surrounding the ischaemic tissue. This follow-up experimental study offers further evidence that Glubran 2((R)) is a safe embolizing material for human use as far as its chemical activity is concerned.

Diffusion-weighted imaging (DWI) has been shown to be highly sensitive in detecting acute cerebral infarction, but its use in detecting hypoxic-ischemic encephalopathy (HIE) in neonates is still controversial. Moreover, few reports concern pre-term infants with possible periventricular leukomalacia (PVL). We examined the ability of this technique to detect cerebral changes in the acute phase of PVL. Fifteen MR examinations were performed in 11 pre-term infants (mean age 3.4 days, range 2-6 days). Conventional DWI sequences, apparent diffusion coefficient (ADC) maps, and US obtained in the acute phase were compared. All the neonates underwent US follow-up up to 4 months after delivery; those with suspected PVL also underwent MRI follow-up for up to 2 months. Qualitative and quantitative evaluations were performed to assess the presence of DW changes compatible with PVL. Diffusion-weighted MRI showed signal hyperintensity associated with decreased ADC values in 3 subjects (27%). In these patients conventional MRI sequences were interpreted as normal and US (performed at the same time) as doubtful in 2 and compatible with PVL in 1 subject. The MRI and US follow-up confirmed severe damage in all these patients. In 1 neonate hemorrhages involving the germinative matrix were identified. In 8 neonates MRI was considered normal. In these subjects US follow-up (up to 4 months) confirmed no signs of PVL. Diffusion-weighted imaging may have a higher correlation with later evidence of PVL than does conventional MR imaging and US when performed in the acute phase of the disease.

Fluid-attenuated inversion recovery (FLAIR) sequence is currently used in clinical practice. Some reports emphasize the possibility that, in pathologic conditions, intravenous injection of gadolinium chelates may lead to an increased signal inside the cerebrospinal fluid (CSF). The aim of this study was to evaluate the presence of CSF signal changes in pathologic conditions causing blood-brain barrier disruption or neovascularization when imaging is performed after intravenous injection of gadolinium. We obtained FLAIR sequences after gadolinium injection from 33 patients affected by different intracranial pathologies and 10 control subjects. Patients were affected by ischemic stroke in the subacute phase, from 2 to 7 days from onset of symptoms (12 patients), meningiomas (8 patients), high-grade gliomas (5 patients), previous surgical procedures for intra-axial neoplasms (5 patients), and multiple sclerosis with active plaques (3 patients). Magnetic resonance imaging was performed in patients and controls using a 1.5-T magnet, using T2- and T1-weighted FLAIR sequences. The FLAIR sequence was acquired before and 1-3 h after injection of a standard dose of gadolinium. In those patients affected by ischemic lesions, FLAIR sequences were repeated the next days and 3-4 days later. The CSF signal was visually evaluated by two readers and scored from 0 to 3 depending by the degree of enhancement. The location of CSF signal changes (close to the lesion, hemispheric, or diffuse) was also considered. The CSF signal was markedly increased after 3 h from intravenous injection of gadolinium in all the patients with stroke, in those with previous surgery, and in those with high-grade gliomas whose neoplasm's surface was in contact with the subarachnoid spaces (SAS) or ventricles; a strong enhancement was also evident inside the necrotic component of the tumor. The CSF changes were more evident close to the pathology and/or in the hemisphere involved by the pathology. Moderate CSF enhancement was observed in the SAS close to meningiomas. No signal changes were evident in all the others. In those patients with stroke imaged in the following days, CSF signal showed to be diffuse to both hemispheres the next day and returned to normal values within 2 days. In patients affected by pathologies with blood-brain barrier breakdown or neovascularization close the SAS or the ventricles, CSF changes, related to gadolinium leakage, are likely when FLAIR sequences are acquired 2-24 h after i.v. injection of the contrast. This pattern should be known in order to differentiate it from that of subarachnoid hemorrhage.

Background and Purpose: Risk of developing ischemia is higher in patients with reduced cerebrovascular reactivity than in those with preserved cerebrovascular reactivity. Therefore, we assessed cerebral hemodynamic modifications in patients with unilateral stenosis of the internal carotid artery by using perfusion-weighted MR imaging to determine if these modifications underlie or anticipate ischemic signs and symptoms., Methods: Fifteen patients with unilateral 70-90% carotid artery stenosis were studied with digital subtraction angiography and perfusion-weighted MR imaging. Their findings were compared with those of 15 age- and sex-matched control subjects. Regional cerebral blood volume (rCBV) and mean transit time (MTT) values were calculated in the middle cerebral artery and border zone territories., Results: No significant difference was noted in rCBV and MTT values between the hemispheres in the symptomatic patients. There was a significant difference in MTT values in the border zones between patients and control subjects. MR images in patients and control subjects did not reveal large territorial infarcts and did reveal similar white matter lesion burdens., Conclusion: There is adequate compensation of unilateral stenosis when the stenosis is less than 90%. The risk of stroke is higher in patients with stenoses exceeding 70%, mostly because of decreased collateral reserve when confronted with emboli.

Background and Purpose: Preoperative assessment of the anatomy and dynamics of cerebral circulation for patients with giant intracranial aneurysm can improve both outcome prediction and therapeutic approach. The aim of our study was to use perfusion MR imaging to evaluate cerebral hemodynamics in such patients before and after extraintracranial high-flow bypass surgery., Methods: Five patients with a giant aneurysm of the intracranial internal carotid artery underwent MR studies before, 1 week after, and 1 month after high-flow bypass surgery. We performed MR and digital subtraction angiography, and conventional and functional MR sequences (diffusion and perfusion). Surgery consisted of middle cerebral artery (MCA)-internal carotid artery bypass with saphenous vein grafts (n = 4) or MCA-external carotid artery bypass (n = 1)., Results: In four patients, MR perfusion study showed impaired hemodynamics in the vascular territory supplied by the MCA of the aneurysm side, characterized by significantly reduced mean cerebral blood flow (CBF), whereas mean transit time (MTT) and regional cerebral blood volume (rCBV) were either preserved, reduced, or increased. After surgery, angiography showed good canalization of the bypass graft. MR perfusion data obtained after surgery showed improved cerebral hemodynamics in all cases, with a return of CBF index (CBFi), MTT, and rCBV to nearly normal values., Conclusion: Increased MTT with increased or preserved rCBV can be interpreted as a compensatory vasodilatory response to reduced perfusion pressure, presumably from compression and disturbed flow in the giant aneurysmal sac. When maximal vasodilation has occurred, however, the brain can no longer compensate for diminished perfusion by vasodilation, and rCBV and CBFi diminish. Bypass surgery improves hemodynamics, increasing perfusion pressure and, thus, CBFi. Perfusion MR imaging can be used to evaluate cerebral hemodynamics in patients with intracranial giant aneurysm.

Background and Purpose: The use of MR angiography and contrast-enhanced T1-weighted MR imaging in cases of acute cerebral ischemia may be helpful in the evaluation of middle cerebral artery (MCA) occlusion and leptomeningeal collaterals, respectively. The aim of our work was to investigate the relationship between MCA occlusion, T1-weighted vascular contrast enhancement, hemodynamic alterations, and tissue damage in cases of acute ischemic stroke., Methods: We studied the MCA territory in 15 patients with acute ischemic stroke within 8 hr of symptom onset. The first MR imaging study (<8 hr after onset) comprised diffusion-weighted imaging, MR angiography, perfusion-weighted imaging, and contrast-enhanced T1-weighted MR imaging sequences. Follow-up MR imaging, performed 1 week later, consisted of MR angiography and T2-weighted fluid-attenuated inversion recovery MR imaging., Results: Early MR angiography showed MCA stem occlusion in nine of 15 patients. Patients with MCA occlusion had significantly larger areas of abnormality on early diffusion-weighted images, significantly larger areas of altered hemodynamics, larger final lesion volumes, and poorer clinical outcome. Among the nine patients with MCA stem occlusion, vascular enhancement was marked in seven and absent in two who had complete MCA infarcts and poor clinical outcome. Among patients with MCA patency, vascular enhancement was marked in only one, mild in four, and absent in one. Patients with marked vascular enhancement had significantly larger regions of altered hemodynamics and significantly higher asymmetries in both regional cerebral blood volume and mean transit time because of increased values in the affected hemisphere., Conclusion: Among patients with stroke with MCA occlusion, marked vascular enhancement and increased blood volume indicate efficient leptomeningeal collaterals and compensatory hemodynamic mechanisms.

Our aim was to relate MRI findings in patients with severe traumatic brain injury (TBI) to clinical severity and long-term outcome. We studied 37 patients with severe TBI, who were submitted to clinical assessment for disability and cognition and to MRI 60-90 days after trauma. Clinical assessment was also performed 3, 6 and 12 months later. The number and volume of lesions in various cerebral structures were calculated semiautomatically from FLAIR and fast field-echo images. Possible correlations between total and regional lesion volume and clinical deficits were then investigated. The frontal and temporal lobes were most frequently involved. Total lesion volume on FLAIR images correlated significantly with clinical outcome, whereas that on FFE images did not. Regional analysis showed that FLAIR lesion volume in the corpus callosum correlated significantly with scores on disability and cognition scales at the first clinical assessment. FLAIR lesion volume in the frontal lobes correlated significantly with clinical scores 1 year later.

Introduction: We studied the hippocampal region using Fluid Attenuation Inversion Recovery (Turbo-FLAIR) sequences to detect signal intensity abnormalities, and volumetric sequences to detect cortical thickness changes, in patients with drug-resistant temporal epilepsy., Materials and Methods: We examined 30 patients with drug-resistant temporal epilepsy with a 1.5 Tesla unit (NT 15 Philips Gyroscan). Conventional SE, Turbo SE, IR, Turbo-FLAIR, volumetric 3D sequences on coronal plane, PD, T2-weighted SE sequences on axial plane, T1-weighted SE on sagittal plane were performed. Signal intensity and volumetric computerized measurements were obtained using the SUN system., Results: Differences in signal intensity values between the two hippocampal regions were found in 18 patients with Turbo-FLAIR sequences. In 6 of these patients no significant differences in computerized evaluation of signal intensity were detected with either conventional or Turbo-SE sequences. Volumetric analysis showed hippocampal cortex thinning in 9 of 18 patients with hippocampal signal intensity abnormalities., Conclusions: Turbo-FLAIR were the best sequences for the detection of signal intensity changes in the hippocampal region. Such changes are strongly suggestive of hippocampal sclerosis, especially when associated with cortical atrophy.

Thirty-six patients with a peripheral localized nerve lesion (18 of median nerve, 7 of ulnar nerve, 2 of radial nerve, 1 of lateral cutaneous brachii nerve, 1 of sciatic nerve, 5 of peroneal nerve and 2 of tibial nerve), were evaluated by Computed Tomography (CT). We used a high resolution scanner (Siemens Somatom CR) and we performed 2mm thickness slices. Sagittal and coronal reconstructed images were obtained too. Thirty-two out of 36 patients underwent surgery. CT scan was useful in all cases in defining the relationship between nerve lesions and surrounding tissues and in planning surgical procedures. The CT evaluation of tissues densities and characteristics allowed us to define the pathologic nature of the lesions in 10 cases.

Gelastic (laughing) epilepsy, relatively uncommon, is usually associated with hypothalamic hamartomas, pituitary tumors, astrocytomas of the mammillary bodies, and dysraphic conditions. Cases of unknown etiology are rare. In three of the four cases reported here, the diagnoses were hamartoma of the tuber cinereum; lobar holoprosencephaly; and lissencephaly type I, grade 2. In the fourth, radiographic investigation gave a normal result; a genetic etiology was suggested because of bilateral familial idiopathic epilepsy. In all patients, EEGs showed both focal spikes and generalized spike-and-wave discharges. The primary underlying neurophysiologic disorder may be provoked by the diffuse hyperexcitability of the cortex and subsequent firing of the thalamocortical networks with which the cortical brain is reciprocally interlinked.

Hemorrhagic infarction subsequent to ischemic brain damage, even if small, slight, or marbled, can be detected by CT. The mechanisms that give rise to this transformation in humans are not well elucidated. Previous reports indicate that hemorrhagic infarction is most common in embolic stroke and large infarcts, and can worsen the clinical state of ischemic patients. We examined 36 patients with supratentorial ischemic signs and symptoms within the first hours after onset. CT was used to judge if hypodensity on early CT studies might predict the development of hemorrhagic infarction. Angiography was used to observe the site of arterial occlusion, the state of collateral circulation, and the mechanisms of late reperfusion. Hemorrhagic infarction was present in 18 of our 36 patients. Angiography revealed occlusion of the middle cerebral artery or internal carotid artery (three cases) in all patients. Hypodensity was present on early CT studies in all of the 18 patients who developed hemorrhagic infarction. The finding of hypodensity on CT studies performed soon after embolic ischemic stroke is strongly predictive of hemorrhagic transformation.

The early CT finding of an hyperdensity of a portion of the middle cerebral artery Hyperdense Middle Cerebral Artery Sign (HMCAS), in patients with supratentorial stroke, is often indicative of an embolic occlusion. Aim of this study was to verify the incidence and reliability of the HMCAS and its possible correlation with early CT findings and with the extent of late brain damage. We studied 36 patients presenting with symptoms of stroke in the MCA territory, by means of CT and angiography performed respectively within 4 and 6 hours. Follow-up CT scans were then obtained after one week and three months from the ischemic event. The HMCAS was present in 50% of our patients and in this group it always correlated positively with the angiographic finding of occlusion. The same group presented a high incidence of early CT hypodensity (88%). Finally the presence of HMCAS might be considered a negative prognostic sign for the development of extensive brain damage.

We performed serial baseline and gadolinium (Gd)-DTPA-enhanced MRI in 4 patients with definite multiple sclerosis. Studies were performed every month for a total of 4 scans. We obtained short TR/short TE sequences at 10 and 60 minutes after Gd-DTPA injection. All patients had multiple hyperintense lesions seen on baseline MRI with long TR/short and long TE. There was Gd-DTPA enhancement in new, enlarging, and preexisting lesions that were unchanged in size. The enhancing lesions were always seen on T2-weighted images. There was no difference in enhancement between the 10- and 60-minute studies. Six of 85 preexisting lesions enhanced whereas all new or enlarging lesions enhanced. Enhancement persisted in only 1/3 of the new or enlarging lesions, suggesting that MR enhancement is a transient phenomenon due to local temporary blood-brain barrier breakdown. Our data indicate that Gd-DTPA enhancement monitoring is more sensitive than unenhanced MRI for detecting disease activity in MS.

A child with microcephaly, facial dysmorphisms, seizures, and congenital cardiopathy is presented. On the basis of skull x-rays, electroencephalogram, transillumination of the head, and computed tomography (CT) scan, the diagnosis of semilobar holoprosencephaly was made. The heterogeneous etiology of the disorder is discussed in order to evaluate the recurrence risk. The usefulness of CT scan for the classification in the different types of holoprosencephaly is stressed.