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A modified spinal cord puncture technique that was combined with CT metrizamide syringography for the evaluation of potentially cystic spinal cord lesions has been used in 5 patients. This procedure proved to be safe and efficacious in the preoperative differentiation of cystic neoplasms from syringohydromyelia. It also aided in planning a surgical approach by revealing details of the tumor location and/or syrinx dynamics. Spinal cord puncture associated with CT metrizamide syringography has a role in the diagnosis and therapy of patients with cystic spinal cord lesions.

Three cases of documented sarcoid meningoencephalitis were reviewed. Computed tomography (CT) showed enhancing, perivascular, linear, and nodular areas along the subarachnoid space, extending deep into the white matter. In one case the perivascular granulomatous infiltration, which caused small vessel periangiitis, gave rise to a CT pattern closely resembling that of arteriovenous malformation or infarction with gyral enhancement. This infiltrative pattern might be seen in other chronic meningeal processes. The pathophysiology responsible for the unusual CT appearance and the differential diagnosis are discussed.

Arterial bolus dynamic computed tomography (ABDCT) was performed on 52 patients presenting with intracranial and intraspinal disorders. Rapid sequential ABDCT scans were obtained during selective intraarterial injection of a small bolus of contrast material following conventional angiography. By this method, the local intravascular iodine level was maximized, allowing for improved contrast resolution of central nervous system lesions. Thirty-eight patients had a known diagnosis. In 35 of these, ABDCT was helpful in delineating tumor margins at the base of the skull and demonstrating tumor or arteriovenous malformation vascularity. In 14 patients, the diagnosis was obscure using conventional computed tomography. In eight of these, ABDCT suggested a distinction between infarct, neoplasm, and inflammatory process. In the remaining six, ABDCT was noncontributory.

Six patients with masses of the anterosuperior portion of the third ventricle were imaged with MR and CT. Four patients had proved colloid cysts, one patient had a proved astrocytoma, and one patient had a presumed colloid cyst. Multiplanar MR imaging provided accurate localization of the anterosuperior third-ventricle mass in all cases. The MR intensity characteristics of the colloid cysts varied and the astrocytoma could not be differentiated from the colloid cysts on MR. The astrocytoma contained a calcification that was clearly demonstrated on CT but was difficult to appreciate on MR. Neither MR nor CT was useful in predicting success of stereotactic aspiration of the colloid cysts in this small series, but the presence of thin, low-viscosity cyst contents could be suggested by both examinations.

• Prospective study of patients admitted to a hospital for closed head injury showed that nine patients (nearly 3%) became mute for varying periods despite recovery of consciousness and communication through a nonspeech channel. Computed tomography (CT) showed subcortical lesions situated primarily in the putamen and internal capsule of four patients, whereas four of the five patients without subcortical lesions had left-hemisphere cortical injury. The patients without subcortical injury visualized by CT exhibited a longer duration of impaired consciousness consistent with severe diffuse brain injury and they showed more long-term linguistic deficits. We related our findings to recent studies of atypical aphasia after occlusive vascular lesions of the basal ganglia.

Vertebral expansion may be caused by both benign and malignant disease processes. Recognition of such lesions on radiographs facilitates accurate diagnosis in many cases.

✓ Magnetic resonance (MR) imaging was performed in 94 patients who sustained closed head injury of varying severity. Results of MR studies obtained after the intensive care phase of treatment disclosed that intracranial lesions were present in about 88% of the patients. Consistent with the centripetal model of progressive brain injury proposed in 1974 by Ommaya and Gennarelli, the depth of brain lesion was positively related to the degree and duration of impaired consciousness. Further analysis indicated that the relationship between depth of brain lesion and impaired consciousness could not be attributed to secondary effects of raised intracranial pressure or to the size of intracranial lesion(s).

Combined intrathecal metrizamide and arterial injection of contrast medium during dynamic computed tomography scanning was used to define the morphology and topographic aspects of a thoracic arteriovenous malformation. The information obtained from this new technique was decisive in establishing the operability of the lesion.

It has been customary to designate crescent-shaped subdural hematomas at angiography as "acute" and biconvex hematomas as "chronic."Analysis of angiograms in 57 proven cases of subdural hematoma reveals that: (1) only 14 per cent of subdural hematomas have a biconvex shape; (2) crescent-shaped hematomas occur at any time interval after injury; and (3) biconvex hematomas may occur any time after 11 days. We conclude that there is no valid basis for predicting the age of a subdural hematoma from its configuration at angiography.Since the shapes of the hematomas at angiography do not correlate with the clinical stages of subdural hematoma, the terms "acute" and "chronic" are best not employed in the radiologic description.The preponderance of biconvex hematomas in the older age group suggests that cerebral atrophy may play a role in determining the shape of a subdural hematoma.

The authors describe a simple method of percutaneous femoral artery catheterization for cerebral angiography in children, using a 19 gauge disposable scalp vein needle.

Tim factors and mechanisms which consistently deliver newly overwintered adults of the ambrosia beetle Trypodendron lineatum (Olivier) to specific host trees under specific conditions have been considered. Studies and analyses of the behavioural patterns of the beetle in respect to light, host tree factors, and factors of the environment were made in recognition of the fact that preliminary research results demonstrated the predominant role that reactions to light played!, in the behaviour of the beetle. The results of the studies showed that the beetles, before flight, were strongly phototacstic at temperatures in the range of 5° to 56°C. Positive photic response was inhibited in an increasing percentage of individuals at temperatures above 56°. At 38°C, positive response to light by the beetles ceased to exists. The non-flown beetles reacted quickly to angular deviations of alignment in respect to a light source and turned, with almost equal readiness toward the light regardless of its angle. The beetles' responses to light may be classified as follows: (1) not inhibited, the beetles immediately, move toward the source of light; (2) initially inhibited positive response; (3) inhibited positive response, the beetles may or may not initially inhibited but the general movement toward She light source is not direct; (4) completely inhibited response, the beetles move with no apparent response to light. The photopositive response was found to mask: the other potential capabilities of the non-flown beetles. Exclusion of the photic stimulus from flight-inexperienced beetles resulted in response to host odour in an odour field. Flight experience was found to modify partially the simple photic reaction of some individuals in the absence of host odour, but the majority of the beetles' responses remained unchanged. The behaviour of Trypodendron is not strictly stereotyped in the sense that it follows a definite pattern. While flight may be normal as a conditioning mechanism preparatory to alighting and host finding, response to an "attractive” odour source and subsequent boring behaviour may be exhibited, in the absence of previous flight experience, under certain conditions.

The herpes simplex virus produces a severe localized necrotizing encephalitis of specific areas of the brain, usually the temporal or adjacent portions of the frontal lobes. This often results in an abnormal brain scan and carotid angiograms, showing a mass not observed in other central nervous system viral infections. Positive diagnosis is made by brain biopsy and recovery of the virus. The efficacy of the antiviral agent idoxuridine is as yet unproved, but its introduction has heightened interest in earlier, more accurate clinical diagnosis.This report concerns 4 cases which showed temporal or frontal mass effects at angiography. The 2 cases in which the virus was obtained during life also showed abnormal radionuclide images.Demonstration of the evolution of these abnormalities on serial scans and angiograms confirms the rapidity of the necrotizing process in herpes simplex encephalitis.

The authors describe a method of obtaining anteroposterior (orbital) views of the internal auditory canals during myelography of the posterior fossa. This projection simplifies anatomical orientation and renders a clear view of the internal auditory canal and its contents.

A young man with conductive hearing loss, pulsatile tinnitus, and a mass behind the tympanic membrane was found to have a persistent stapedial artery and an aberrant internal carotid within the middle ear cavity. The stapedial artery is a continuation of the primitive hyoid branch of the internal carotid artery which terminates as the middle meningeal artery, but normally regresses in the 24-mm embryo. Radiographic findings of the persistent stapedial artery include absence of the foramen spinosum, a special opening for the stapedial artery in the temporal bone best seen on tomograms, and demonstration of the characteristic course of the artery on carotid angiograms.

Radionuclide images of patients with angiographically diagnosed primary intracerebral hemorrhage (ICH) were reviewed to determine the temporal relationship between a positive image and the onset of symptoms. Four of 9 brain images in 8 patients were positive; no definite temporal relationship was observed. The results suggest that current methods of radionuclide imaging have only a limited application in primary ICH.

• The diagnosis of diffuse brain injury is considered when computed tomography provides no evidence of an intracranial mass lesion in acute nonmissile head injury. Magnetic resonance imaging (MRI) of a young woman who had sustained severe diffuse brain injury five years earlier disclosed multifocal lesions involving the frontal, temporal, parietal, and occipital lobes. We report the results of serial neurobehavioral assessment for clinical correlation with the brain lesions visualized by MRI. Pending confirmation of our findings in a series of patients studied by MRI during the acute and chronic stages of recovery from head injury, we postulate that the presence and type of neuro-behavioral sequelae of diffuse brain injury are related to the intrahemispheric loci of predominantly white matter lesions and degeneration.