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Stroke is the third leading cause of death and is a major cause of long-term disability. Neuroprotective treatment within a 4-hour «therapeutic window» has proved highly efficacious in reducing morbility and mortality in animal model. It is with this background that the need for emergent diagnosis and therapy of acute stroke in strongly suggested. Computed tomography (CT) shows the parenchymal changes of acute stroke too late to be helpful, and its role has been primarily to evaluate the possibility of intracerebral or subarachnoid hemorrhage. While conventional magnetic resonance (MR) imaging can demonstrate parenchymal abnormalities 4–6 hours after ischemia, newer techniques such as diffusion-weighted MR imaging (DWI) hold promise that a diagnosis of ischemia can be made within minutes after the acute event. In this article compares different aspects of hyperacute cerebral ischemia depicted at diffusion-weighted imaging before infarction is depicted at conventional MR or CT scans. DWI techniques may improve stroke diagnosis and may contribute to advances in treatment.

Diastematomyelia is an uncommon defect of the neural axis and spinal column involving a sagittal cleft in the spinal cord and/or cauda equina, and phylum terminale; a spur of bone, cartilage or fibrous tissue separes two distinct spinal compartments and hemicords. A true double cord, each with four nerve roots is traditionally defined as diplomyelia. Associated cutaneous, skeletal or visceral anomalies are very common. Clinical onset occurs most frequently in adulthood, with low back pain, perineal hyperpatia and symptoms of motor and sensory deficit. In infantile onset cases pain is less frequent while neurologic symptoms prevail with orthopedic complications. Symptoms generally resemble tethered cord syndrome. Several hypotheses have been advanced to explain the embryopathogenesis of diastematomyelia, and they give rise to the current accredited theory, recently proposed by Pang and Coll. This paper resembles these hypoteses and explanes the actual accepted theory: the formation of an “ectopic or accessory neurenteric canal” abnormally joining the ectodermal and entodermal layers, bisects the notocord in its cranial development from Hensen's node; a regional splitting of the notocord takes place at this level and the maturative outcome is a split spinal cord with spinal dysraphism. Recently (1992) Pang and Coll. perfected this theory postulating a migration of mesenchymal cells along the accessory neurenteric canal, to form an “endomesenchymal tract”. The presence of displaced mesenchyma other than ectoderm and endoderm, is able to explain the entire complex of associated anomalies in diastematomyelia. Finally, they have by-passed the traditional distinction between diastematomyelia and diplomyelia, proposing a new unified theory of “Split Cord Malformations” (SCM).

This article presents some anatomic and neuroradiologic clues in the identification of intrinsic tectal tumours and the main related problems of differential diagnosis. The majority of intrinsic tectal lesions are low-grade gliomas that have been recognized as a potential cause of late-onset aqueductal stenosis. The superb sensitivity of magnetic resonance (MR) imaging and its multiplanar imaging capability allow an optimal diagnostic accuracy in the tectal region. For this reason, MR imaging should be included in the work-up of all patients with neurological findings of brain stem dysfunction and late-onset aqueductal stenosis. Tectal gliomas particularly merit an accurate MR long-term follow-up monitoring, since they may ultimately show evidence of progressive growth and require therapeutic intervention to maintain disease control.

To identify pituitary iron overload in patients with transfusion-dependent thalassemia major causing secondary hypogonadism, we prospectively evaluated signal intensity abnormalities of the anterior lobe of the pituitary gland of 30 patients comparing spin-echo, gradient-echo imaging and pituitary T2 relaxation times measurement. We found that pituitary iron overload can best be assessed by MR imaging using gradient-echo T2*-weighted technique to establish signal reduction in the anterior lobe of the pituitary gland. This finding is correlated to increasing serum ferritin level — a parameter that reflects the severity of iron overload, and is more evident in patients with secondary hypogonadism. This finding is consistent with the hypothesis of hypogonadotrophic pituitary insufficiency due to iron-induced cellular damage.

We compared T2-weighted fast spin-echo (FSE) magnetic resonance (MR) imaging and conventional spin-echo (CSE) T2-weighted imaging in the detection of brain lesions of multiple sclerosis (MS). 20 patients with clinically definite MS underwent brain imaging with both FSE and CSE T2-weighted imaging. There was no significant difference in total number of lesions detected on FSE vs CSE (1354 vs 1378). Slightly more periventricular and subcortical lesions were detected using CSE than FSE, whereas more posterior cranial fossa lesions were detected by FSE. There was no statistically significant difference in the signal intensity (SI) ratio of MS lesions to that of surrounding normal white matter on FSE vs CSE, however the SI ratio of MS lesions was lower on FSE T2-weighted images (FSE ? 1.87 ± 0.39 vs CSE = 2.09 ± 0.36). Considerable time savings can accrue when substituting FSE for CSE sequences in T2-weighted imaging, and this is a compelling reason to employ such sequence in clinical practice. Our results suggest that although CSE sequences are required to confirm the diagnosis of brain involvement of MS lesions, T2-weighted FSE sequences can replace CSE sequences in long term monitoring especially when patient's movements preclude useful investigation and when optional scanning planes are required.

We report the results on a long-term study of the effects of hyperbaric oxygen (HBO) therapy on multiple sclerosis assessed by MR imaging. Ten patients with clinically definite multiple sclerosis were studied by MR imaging during a two year HBO treatment of disease. A transient benefit of HBO therapy on brain multiple sclerosis was revealed for patients with relapsing-remitting disease course that was demonstrated at MR imaging. However, no significant changes in the total number and size of brain lesions was demonstrated on MR images in long-term follow-up of patients treated with HBO in accordance with the results of clinical outcome observed in this study.

L'encefalopatia di Wernicke è patologia legata a deficit di tiamina, conseguente spesso ad alcolismo cronico, che presenta peculiari localizzazioni encefaliche e conseguenti manifestazioni cliniche. Viene descritto un caso di encefalopatia di Wernicke in un uomo di 25 anni, non alcolista, valutandone le lesioni alla risonanza magnetica in fase acuta e seguendone l'evoluzione. Il paziente, con anamnesi patologica prossima di colite amebica, presentava un progressivo e rapido deterioramento delle capacità cognitive preceduto da una severa ipoacusia e riduzione dell'acuità visiva, discromatopsia, allucinazioni visive, prosopoagnosia, disartria. Viene eseguita una RM dell'encefalo (con apparecchio Vectra, GE, operante a 0,5 T; sequenze SE DP e T2 ponderate e T1, prima e dopo Gd-DTPA) che evidenzia aree lesionali espresse da iperintensità, nelle sequenze a lungo TE, dei corpi mammillari, dei tubercoli quadrigemelli inferiori e (segno semeiologico, per quanto risulta da una revisione della letteratura, non descritto in precedenza tra i reperti dell'encefalopatia di Wernicke) dei tratti ottici. Ad una decisa integrazione alimentare con tiamina segue un repentino miglioramento clinico. Esami RM seriati rivelano una netta riduzione dell'estensione e delle alterazioni dell'intensità di segnale delle aree precedentemente coinvolte fino alla totale normalizzazione dei reperti. Viene discussa la clinica, l'istologia e la presunta patogenesi dell'elettiva localizzazione del danno da carenza di tiamina a carico dell'encefalo, e gli aspetti neuroradiologici, individuando il ruolo dell'RM nell'iter diagnostico di tale patologia.

Gli autori si propongono di valutare le modificazioni del segnale RM a livello ipofisario nella emosiderosi secondaria in pazienti affetti da beta-talassemia major. Lo studio è stato condotto prospetticamente su un gruppo di 20 pazienti in regime alto-trasfusionale e trattamento ferro-chelante e su 10 volontari sani come gruppo di controllo. Gli esami RM sono stati condotti con apparecchiatura a magnete superconduttivo a 0,5T con sequenze SE TI-dipendenti e GRE TE*-dipendenti. Il sovraccarico di ferro è stato valutato mediante il dosaggio della ferritina sierica. è stata effettuata una valutazione quantitativa delle immagini RM SE T1- e GRE T2*-dipendenti attraverso la misurazione, mediante ROIs, dell'intensità di segnale (IS) del lobo anteriore dell'ipofisi rapportata a quella del tessuto adiposo subcutaneo, nei pazienti e nel gruppo di controllo. Al fine di verificare l'esistenza di differenze statisticamente significative tra i valori rilevati nei pazienti e nel gruppo di controllo è stato applicato il test t di Student. Sono state dimostrate differenze statisticamente significative ( P La RM si è dimostrata metodica non invasiva utile nella valutazione del sovraccarico di ferro a livello ipofisario nei pazienti talassemici. Il reperto RM in questa evenienza è costituito dalla riduzione dell'intensità di segnale dell'ipofisi, e ciò è più evidente nelle immagini GRE TE*-dipendenti.