Luigi Maria Fantozzi

Early collateral blood supply and late parenchymal brain damage in patients with middle cerebral artery occlusion.

We angiographically studied 80 patients within 6 hours after the onset of ischemic supratentorial infarction. From this group we selected 36 patients with middle cerebral artery occlusion who survived. In these 36 patients, we compared the presence of a collateral blood supply during the early phase with the extent of final parenchymal brain damage obtained by computed tomography 3 months after the event. The presence of a collateral circulation during the first few hours after the stroke reduced the size of the final parenchymal brain damage in patients with middle cerebral artery stem-trunk occlusion. The collateral blood supply was more efficient in patients who had no significant stenosing lesions of the extracranial internal carotid artery. Our data confirm that the lenticulostriate arteries are end arteries not supplied by collateral blood vessels and suggest that lesions formerly thought to be caused by hemodynamic mechanisms (watershed infarcts) or arteriolar lesions (lacunar infarcts) may be due to middle cerebral artery occlusions.

Hyperdense middle cerebral artery CT sign

SummaryThe 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 erly CT hypodensity (88%). Finally the presence of HMCAS might be considered a negative prognostic sign for the development of extensive brain damage.

Correlation between MRI findings and long-term outcome in patients with severe brain trauma

Abstract 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.

Pre-surgical planning and MR-tractography utility in brain tumour resection.

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 pre-surgical 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 post-surgical 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.

Magnetic resonance imaging in Posterior Reversible Encephalopathy Syndrome: report of three cases and review of literature

IntroductionEclampsia 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 discussionWe report the MR imaging findings of three patients with eclampsia and PRES as well as a careful review of literature.

Apparent diffusion coefficient obtained by magnetic resonance imaging as a prognostic marker in glioblastomas: correlation with MGMT promoter methylation status

ObjectiveTo 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).MethodsThis 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.ResultsTwenty-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.ConclusionsMinimum 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.Key Points• Diffusion-weighted MR imaging (DWI) provides new insights into glioblastoma multiforme (GBM)• DWI ADCmin values can predict the methylation status of MGMT promoter.• The MGMT promoter methylation group survived longer than the unmethylated group.• Patients with high ADCmin values survived longer than patients with low values.

Role of magnetic resonance tractography in the preoperative planning and intraoperative assessment of patients with intra-axial brain tumours

PurposeThis 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 methodsTwenty-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.ResultsIn 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.ConclusionsMagnetic 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.RiassuntoObiettivoValutare la possibilità di identificare definiti fasci di sostanza bianca localizzati in prossimità di un tumore cerebrale; definire le relazioni anatomiche e topografiche tra gli stessi fasci di sostanza bianca e il tumore; verificare la possibilità di integrare le immagini trattografiche nell’ambito di un pacchetto di immagini anatomiche tridimensionali da inviare a un sistema di neuronavigazione; valutare l’impatto di queste informazioni sulla programmazione chirurgica e analizzare, prima e dopo l’intervento chirurgico, le condizioni cliniche dei pazienti, come indici di integrità funzionale delle fibre stesse.Materiali e metodiVenticinque pazienti, che avevano preventivamente eseguito uno studio del tensore di diffusione, sono stati successivamente sottoposti a intervento neurochirurgico. Mediante un software dedicato, sono state ottenute le relative mappe colorimetriche e ricostruite in tre dimensioni le traiettorie dei fasci di sostanza bianca adiacenti alla neoformazione che sono state elaborate per la pianificazione preoperatoria. La pianificazione, effettuata mediante il neuronavigatore, si è basata sull’analisi della localizzazione e del decorso dei principali fasci di sostanza bianca adiacenti la lesione (fascio cortico-spinale, radiazione ottica e fascicolo arcuato). È stato chiesto a due neurochirurghi se e come la disponibilità della trattografia avesse modificato l’accesso e/o l’approccio intraoperatorio alla neoplasia. Tutti i pazienti sono stati valutati clinicamente sia in fase pre-che post-operatoria, a 1 mese dall’intervento, per definire la presenza di sintomi riferibili a un coinvolgimento dei fasci mielinici oggetto dello studio e verificare quindi, dal punto di vista clinico, l’integrità degli stessi in seguito all’intervento.RisultatiIn un paziente il tumore era localizzato a distanza da tutti i fasci considerati e non determinava sugli stessi effetti compressivi. Globalmente, dei 75 fasci considerati, 40 non avevano rapporto anatomico con il tumore, non venivano dislocati dallo stesso o non risultavano visualizzabili in tutto il loro decorso. L’analisi dei restanti 35 fasci di sostanza bianca considerati ha determinato una modifica a priori dell’approccio chirurgico di corticotomia in 4 pazienti (16%) senza casi di discrepanza nel giudizio tra i due neurochirurghi e un impatto sulla definizione dei limiti di resezione durante l’intervento in 17 (68%), risultando complessivamente di impatto sulla procedura chirurgica nell’80% dei casi. Otto pazienti non mostravano sintomi riferibili a un coinvolgimento dei fasci mielinici oggetto dello studio. Nei restanti 17 i sintomi erano riferibili a un coinvolgimento del fascio piramidale, arcuato o della radiazione ottica. Al controllo a 1 mese un paziente, precedentemente asintomatico, riferiva un disturbo del linguaggio a tipo disfasia sensoriale; nei restanti 24 la sintomatologia era invariata con tendenza al miglioramento in 14 dei 17 pazienti sintomatici per coinvolgimento dei fasci mielinici segnalati.ConclusioniLa tecnica della trattografia con RM offre al neurochirurgo una nuova panoramica anatomica che permette una migliore pianificazione della procedura chirurgica di resezione di patologia cerebrale. Nonostante l’elevata incidenza di casi in cui la patologia determina modificazioni che inficiano la possibilità di ricostruire i fasci di sostanza bianca, la tecnica modifica l’approccio chirurgico di corticotomia, consente di definire i limiti di resezione e determina globalmente un cambiamento dell’intervento nell’80% dei casi. Il miglioramento della sintomatologia pre-esistente e l’assenza di nuovi sintomi in fase post-operatoria conferma, a nostro avviso, la sua validità.

Role of contrast-enhanced MR venography in the preoperative evaluation of parasagittal meningiomas

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.

Pre- and intraoperative tractographic evaluation of corticospinal tract shift

BACKGROUND:Magnetic resonance with diffusion tensor image (DTI) may be able to estimate trajectories compatible with subcortical tracts close to brain lesions. A limit of DTI is brain shifting (movement of the brain after dural opening and tumor resection). OBJECTIVE:To calculate the brain shift of trajectories compatible with the corticospinal tract (CST) in patients undergoing glioma resection and predict the shift directions of CST. METHODS:DTI was acquired in 20 patients and carried out through 12 noncollinear directions. Dedicated software “merged” all sequences acquired with tractographic processing and the whole dataset was sent to the neuronavigation system. Preoperative, after dural opening (in 11) and tumor resection (in all) DTI acquisitions were performed to evaluate CST shifting. The extent of shifting was considered as the maximum distance between the preoperative and intraoperative contours of the trajectories. RESULTS:An outward shift of CST was observed in 8 patients and an inward shift in 10 patients during surgery. In the remaining 2 patients, no intraoperative displacement was detected. Only peritumoral edema showed a statistically significant correlation with the amount of shift. In those patients in which DTI was acquired after dural opening as well (11 patients), an outward shifting of CST was evident in that phase. CONCLUSION:The use of intraoperative DTI demonstrated brain shifting of the CST. DTI evaluation of white matter tracts can be used during surgical procedures only if updated with intraoperative acquisitions.

Gelastic Epilepsy A Clinical Contribution

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.