The likelihood of rupture of unruptured intracranial aneurysms that were less than 10 mm in diameter was exceedingly low among patients in group 1 and was substantially higher among those in group 2. The risk of morbidity and mortality related to surgery greatly exceeded the 7.5-year risk of rupture among patients in group 1 with unruptured intracranial aneurysms smaller than 10 mm in diameter.

✓ A limited number of cases have been reported in which gas-containing lumbar disc herniation caused compression of nerve roots. The authors describe two patients in whom computerized tomography scanning revealed a large intraspinal gas collection that appeared to be causing nerve root compression and that was successfully evacuated by percutaneous needle aspiration.

MRI is today the first-choice technique for detection of pituitary microadenomas. The combination of T1-weighted spin-echo, T2-weighted spin-echo and T1-weighted spin-echo after intravenous gadolinium administration gives a clearly positive result in about 70% of cases. In the remaining 30% the hypersignal generated by the contrast agent can hide the smallest lesions. Dynamic MRI is considered capable of visualizing some of the smallest pituitary microadenomas not visible on conventional MRI, and has therefore become the most promising technique to image pituitary lesions. The purpose of this study is to compare the effectiveness of conventional and dynamic MRI. Fifty patients were examined with dynamic contrast-enhanced MRI of the pituitary gland. They were thought to have pituitary adenoma on the basis of clinical and biological data. MRI was performed at 1.5T (Siemens SP 63) with the acquisition of three sequences: 1) T2-weighted sequence 2) Dynamic study: (temporal resolution 17 s) 3) T1-weighted postcontrast sequence. In 10 cases (20%) no pathological findings were seen. In 32 cases (64%) pathological findings were seen both in dynamic and in SE T1 and T2-weighted images. In 8 cases (16%) pathological findings were observed only in the dynamic study. In 8 studies out of 50 (16%) dynamic MRI showed small (less than 7 mm) focal relatively hypointense areas in the pituitary gland, visible neither on SE T2-weighted pre-contrast nor on SE T1-weighted postcontrast images, leading to a diagnostic sensitivity from 64% to 80%. Dynamic MRI did not miss any lesions although in 3 cases the picture was more clear on SE sequences. We can conclude that dynamic MRI study of the pituitary gland improves accuracy in the diagnosis of pituitary microadenomas.

Parole chiave: TC, trauma cranico RIASSUNTO -Sulla base della revisione delle richieste di Tomografia Computerizzata Cerebrale (TC) inoltrate dal Pronto Soccorso al Servizio di Neuroradiologia dell'Ospedale Maggiore Policlinico di Milano, si e osservata una percentuale di casi di trauma cranico pari al 41% degli esami richiesti. E stato quindi effettuato lo studio retrospettivo di 300 casi di trauma cranico indagati con esame TC nel corso di un trimestre, il 92% dei quali e risultato negativo per complicanze intracraniche post-traumatiche. Tenuto canto di un'obiettivita neurologica negativa al momento dell'ammissione in Pronto Soccorso, il 79% dei casi e stato ascritto alla categoria di trauma cranico lieve. Per essi si e rivelata una positivitaper lesioni intracraniche post-traumatiche del 2%, mentre si e osservato che un'obiettivita neurologica positiva e associata alla presenza di lesioni intracraniche con una frequenza del 17%. Si e osservata una maggiore positivita per complicanze intracraniche nei pazienti di eta superiore ai 50 anni, nei casi di incidente stradale, nei casi di trauma in sede parietale e nei casi di amnesia e episodi di vomito successivi all'evento traumatico. Non si e invece riscontrata una maggiore associazione con lesioni intracraniche nei casi di trauma commotivo rispetto ai casi di trauma non commotivo.Gli autori, sulla base della esperienza presentata in questa sede e della revisione della letteratura in merito, propongono alcune linee guida per la gestione dei pazienti affetti da trauma cranico lieve. SUMMARY-We reviewed all cranial CT scans at our Neuroradiological Service requested by the Emergency Room from August 1993 to April1994 and we noted that 41% of them dealt with patients admitted for closed head injuries. A retrospective study of 300 head injured patients who underwent CT examination on admission was performed, CT scans were negative in 92% of cases.All patients with a normal neurological examination at the Emergency Room were regarded as mild head injury patients. This group comprised 79% of all the observations; intracranial lesions were disclosed by CT scans in 2% of them; whereas, in patients with neurological signs, CT scans demonstrated intracranial lesions in 17% of cases.We observed intracranial lesions more frequently in patients over 50 years, or in road accident head injury patients, or in parietal head injury patients and in patients who developed amnesia, or episodes of vomiting following trauma. No relation was found between loss of consciousness and positive CT scans.On the basis of their experience and a review of the literature, we propose some guidelines for the management of mild head injury patients.All patients with a negative neurological examination should undergo 6-12 hours of clinical observation; after this period, they might be simply discharged if there are no clinical changes. 415A Ruolo della tomografia computerizzata cerebrale nel trauma lieve S. Lucchi

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