The authors describe four cases of subependymoma studied with computed tomography (CT) and review 18 previously reported cases in an attempt to define the most characteristic CT presentation of this rare, benign tumor. Subependymoma usually appears as an isodense, or even hypodense, intraventricular tumor on plain CT scan and shows minimal or no enhancement in postcontrast studies. Differential diagnosis between subependymoma and the more malignant true ependymoma is difficult, particularly when the tumor occurs in the posterior fossa. Recognition of subependymoma should prompt the surgeon to attempt radical tumor removal because it can be achieved without sacrificing contiguous tissue and carries a good prognosis.

Only 4 of the 30 previously reported cases of giant sacral schwannomas have been studied with Magnetic Resonance Imaging (MRI). We are reporting 6 more cases, 5 of which had MRI studies. There were 5 women and 1 man (average age 45 years) with long lasting symptoms consisting of lumbosacral and radicular pain accompanied by urinary disturbances and dysaesthetic sensations in the lower limbs. CT clearly defined sacral bone involvement but poorly demonstrated intraspinal tumour extension which was more evident in MRI studies. MRI also clearly showed the intrapelvic extension of the tumour, its relationship with the neighbouring structures and the dumbbell growth pattern due to tumour extension through sacral foramina which are important data for making a pro-operative diagnosis and surgical planning. Surgical treatment consisted of piecemeal tumour resection through a posterior approach in four cases. Two patients underwent operation through an abdominal transperitoneal approach followed by a sacral laminectomy. Total intracapsular resection was apparently achieved in 5 cases. Through an average follow-up period of 9.2 years and despite a rather conservative approach, the recurrence rate has been very low in our series and only one patient had to be re-operated on for tumour recurrence.

A group of 78 severe head injury patients showing computerized tomography (CT) findings of the so-called "diffuse axonal injury" is analyzed. These patients represent 20% of the authors' series of severe head injury. Twenty-three patients showed small intraparenchymal haemorrhages in the CT scan study, 15 intraventricular haemorrhage and 40 patients had both intraparenchymal and intraventricular haemorrhages. Signs of brainstem haemorrhagic contusion were seen in 29 (38%) patients. Generalized brain swelling superimposed on the above findings was present in 75% of the cases. Raised intracranial pressure, which was found in 50% of the patients, correlated with the presence of ventriculocisternal collapse in the CT scan and an unfavourable outcome. Only 4 patients in this series made a good recovery, 13 developed a moderate disability, 11 a severe disability, 12 became vegetative and 38 (49%) died. The prognosis with this post-traumatic lesion is the worst in the authors' severe head injury series after excluding cases with subdural haematoma.

The authors analyze the clinical course of 46 severely head-injured patients who had completely normal computerized tomography (CT) scans through the immediate posttraumatic period (1 to 7 days after trauma). These patients represent 10.2% of a consecutive series of 448 cases of severe head injuries and two-thirds of the cases showing a normal CT scan on admission (the other one-third of the cases developed new pathology). The usual course in these 46 patients after the initial coma was toward progressive neurological improvement, and 35 patients (76%) achieved a functional level of survival. Nine patients (19.5%) remained comatose for several weeks and developed severe disability. There were two fatalities due to medical complications. The final outcome was more closely related to the duration of coma (the longer the duration the worse the result) than to the initial Glasgow Coma Scale (GCS) score. In fact, 26% of the patients in the lower GCS score ranges (3 to 4 points) made a good recovery and 46% developed moderate disability only. These findings indicate that the grim prognostic significance of deep posttraumatic coma is tempered in the presence of a normal scan. However, the absence of CT abnormalities in severely head-injured patients cannot be equated with a good prognosis because in one-fifth of the cases serious permanent disability develops. Sustained elevation of the intracranial pressure (ICP) was not seen in these patients, indicating that ICP monitoring may be omitted in cases with a normal scan. However, since one-third of the patients with a normal admission scan developed new pathology within the first few days of injury, a strategy for control scanning is recommended. Control CT scans performed more than 6 months after injury showed a significantly higher incidence of brain atrophy in patients developing permanent disability than in those who made a good recovery.

The authors surveyed 31 surgical and radiotherapy series comprising over 2300 patients with spinal metastases to determine the influence of factors such as tumor biology and topography, pretreatment neurological status, the presence of a myelographic block, the progression rate of symptoms, and the general medical condition of the patient on both the functional prognosis and the choice of treatment. Both life expectancy and the functional results after therapy are mainly dependent on tumor biology, which in turn determines radiosensitivity. The remaining factors seem to have only complementary predictive power. Because radiotherapy has been found to be as effective as operation plus radiotherapy in the management of the majority of patients with spinal metastases, it is very important to improve the selection of surgical candidates (less than 42% of the total cases) to prevent unnecessary surgery-related morbidity and mortality. Factors considered important in the selection of therapy are the location of the tumor within the spinal canal, the neurological status at the time of treatment, and the systemic condition of the patient.

The authors review the literature on subarachnoid haemorrhage of unknown aetiology (SAHUE) and analyze a personal series of 212 patients diagnosed as SAHUE. These patients represent 30% of all cases of primary SAH admitted over a 14.5 year period. The age, sex, antecedents and initial clinical presentation of patients with SAHUE were indistinguishable from those of patients with subarachnoid haemorrhage due to ruptured aneurysm (SAHRA). However, the present series of SAHUE compare favourably with both a personal and a previously reported series of SAHRA insofar as clinical grade on admission (94% of patients in grades I-II of Botterell), presence of blood on CT (51%), vasospasm (5%), ischaemic deficits (3.3%), persistent hydrocephalus (3.5%), rebleeding (6%) and fatal result (3.9%) are concerned. The amount of blood on CT scan in our patients with SAHUE was associated with a significantly higher incidence of brain ischaemia and hydrocephalus but did not correlate with the Botterell grade on admission or final outcome, which were good in the majority of cases regardless of the presence or not of visible cisternal haemorrhage. The results of the present series confirm that the final prognosis of patients with primary SAH showing normal four-vessel cerebral angiography is essentially favourable.

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The authors surveyed 31 surgical and radiotherapy series comprising over 2300 patients with spinal metastases to determine the influence of factors such as tumor biology and topography, pretreatment neurological status, the presence of a myelographic block, the progression rate of symptoms, and the general medical condition of the patient on both the functional prognosis and the choice of treatment. Both life expectancy and the functional results after therapy are mainly dependent on tumor biology, which in turn determines radiosensitivity. The remaining factors seem to have only complementary predictive power. Because radiotherapy has been found to be as effective as operation plus radiotherapy in the management of the majority of patients with spinal metastases, it is very important to improve the selection of surgical candidates (less than 42% of the total cases) to prevent unnecessary surgery-related morbidity and mortality. Factors considered important in the selection of therapy are the location of the tumor within the spinal canal, the neurological status at the time of treatment, and the systemic condition of the patient.