A. Pierallini

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.

Supratentorial diffuse astrocytic tumours: proposal of an MRI classification

Abstract. The aim of this study was to obtain an MRI severity-related classification of diffuse astrocytic tumours able to integrate the histological data in the grading of such tumours. We studied presurgical MR images of 91 patients with a histological diagnosis of astrocytoma, anaplastic astrocytoma and glioblastoma. A score ranging from 1 to 3 was assigned by two independent readers to each of the following MR features: oedema, mass effect, contrast enhancement, borders, signal homogeneity, necrosis, haemorrhage and flow void. Statistical analysis showed significant differences in the mean MRI scores between the three histological grades. Contrast enhancement was found to be the best predictor of the histological grade followed by necrosis, signal homogeneity and border scores. This classification represents a simple and reproducible means of carefully evaluating some macroscopic characteristics of these tumours. It could be used to integrate histological data especially in cases in which tissue sampling defects may affect the validity of this examination.

Radiological assessment of necrosis in glioblastoma: variability and prognostic value.

Abstract In a previous study, we found that the extent of necrosis was the only radiological feature which correlated significantly with survival in patients with glioblastoma. The aim of this paper was to evaluate the variability and prognostic value of the extent of the necrotic area as seen on contrast-enhanced MRI and CT in a larger series. We studied 72 patients who underwent surgical removal of supratentorial glioblastomas and had CT and/or MRI with contrast medium before surgery; 38, all undergoing the same treatment (surgery plus radiotherapy), were followed clinically. Necrosis within the tumour varied greatly, ranging from none (only 1 case) to involvement of 76 % of the tumour. Survival data in the subgroup suggested that only patients with a small area of necrosis (less than 35 % of the tumour) had a significantly longer survival time. When necrosis involved more than 35 % of the mass, patients had a shorter survival time, without any further correlation with the extent of necrosis.

No differences in corpus callosum size by sex and aging: A quantitative study using magnetic resonance imaging

To identify normal variations in the magnetic resonance imaging appearances of the corpus callosum with regard to sex and age, a prospective study was performed in 130 normal subjects. Callosal measurements were calculated by morphometric analysis. There were no significant sex differences in corpus callosum area or the callosal subregions. The absolute area did not decrease significantly with aging in normal males or females. However, age‐related changes of callosal configuration were shown by a decrease in the ratio of the rostrum and genu to the splenium.

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.

Reversible diffusion MRI abnormalities and transient mutism after liver transplantation

Transient mutism was observed in a liver transplant patient under immunosuppressant therapy with cyclosporine A and antifungal prophylaxis with amphotericin B. Fluid-attenuated inversion recovery and diffusion-weighted images revealed reversible bilateral symmetric hyperintensity located in the frontal motor cortex and corticospinal tracts. These MRI abnormalities may be caused by acute edema, possibly a combination of cytotoxic and vasogenic edema, which resolved with a prompt change in therapy.

Tolosa-Hunt syndrome in a patient with systemic lupus erythematosus

Abstract. We report a case of Tolosa-Hunt syndrome (THS) in a patient with systemic lupus erythematosus studied with MRI. Magnetic resonance showed enlargement of the cavernous sinus and compression of the carotid syphon by enhancing tissue. In particular, fat-suppressed T1-weighted images before and after contrast agent injection and MR angiography showed extension of the abnormal tissue to the apex of the orbit and narrowing of the internal carotid artery. A presumptive diagnosis of THS was made and steroid treatment was started with rapid relief of symptoms. Follow-up MR study after steroid therapy demonstrated sub-total resolution of the neuroradiological findings. Neuroradiological findings in THS are quite typical but they may be subtle; furthermore, the presence of a systemic disease may suggest secondary involvement of the cavernous sinus. Utilization of the appropriate MR techniques and follow-up exams may contribute to the diagnosis of THS even in the presence of other systemic diseases.

Pleomorphic xanthoastrocytoma with CT and MRI appearance of meningioma

Abstract We describe a pleomorphic xanthoastrocytoma (PXA) in a young girl whose frontal lobe location, solid structure, dural tail and MRI signal characteristics led to a preoperative diagnosis of meningioma. PXA should be considered in differential diagnosis of tumours affecting young patients with neuroradiological characteristics suggestive of meningioma.

Metastasis Along the Stereotactic Biopsy Trajectory in Glioblastoma Multiforme

Dissemination of neoplastic cells along the needle trajectory after brain biopsy has been described following biopsy of pinealoblastoma, craniopharyngioma and recently of brain metastasis [2]. To the best of our knowledge tumour seeding during biopsy of glioblastoma has never been reported. In our report we describe a case of metastasis of glioblastoma multiforme (GBM) along the needle trajectory following stereotactic guided biopsy.