[Recanalization of dural sinus occlusion following the disappearance of dural arteriovenous fistula: report of a case]

A 73-year-old female was admitted to our hospital because of disturbed consciousness and left-sided motor weakness. Computed tomographic scans demonstrated a hemorrhagic infarction in the right parietal region. Right carotid angiograms showed both the posterior portion of the superior sagittal sinus (SSS) and the entire left transverse sinus simultaneously occluded. Left carotid angiograms revealed an enlarged occipital artery, which had direct communications to the left sigmoid sinus and the superior petrosal sinus. These findings were consistent with dural arteriovenous fistula (D-AVF). The laboratory examinations yieled normal results. The patient was managed conservatively with glyceol and anticonvulsants for four weeks and eventually recovered with complete resolution of hemiparesis. Follow-up angiography carried out 6 weeks later showed the SSS, partially stenotic, but recanalized with no evidence of venous congestion. The D-AVF still remained opacified, but there was a marked reduction in retrograde flow to the sigmoid sinus. Further repeated angiograms obtained at 10 months after the onset confirmed complete recanalization of the SSS and disappearance of the D-AVF. From the timing of the angiographies, we considered that the sinus occlusion was caused by the high arterial flow to the fistula and its disappearance made recanalization of SSS possible.

Local image filing system in neurosurgery: validity of selective storage of radiographic images

In an effort to achieve efficient image management in the practice of neurosurgery, a clinical data base system was designed and developed to process, store and retrieve neuroradiologic image information on hospitalized patients with the use of a local image filing system (EFPACS-500, Fuji Electric Co., Ltd). Storage and retrieval of radiographic images were studied to quantify existing procedures and to evaluate the validity of new technology. One of our hospitals (Southern Tohoku Research Institute for Neuroscience) has annually produced approximately 100,000 sheets of film radiographs, resulting in a great deal of serious problems, particularly lack of space for storage. In addition, the overall averaged ratio of selected key films to total files of radiographs was estimated to be 16.3% for hospitalized patients during the past 5 years. It is assumed that, by means of digital storage on this selective basis, radiographic storage problems can be solved with the use of the current data base system which efficiently handles image information involving patient care. In the practical view another substantial improvement in this work is the high functionality of the system, with which radiographic images coupled with a variety of clinical data on patients can be stored in a descriptive fashion.

[Clinical effect of nitroglycerin (GTN) on prevention of cerebral vasospasm]

Nitroglycerin (GTN) is widely used as a safe and effective dilator in patients with ischemic heart disease, and it is said that it dilates the cerebral vessels. So the authors are now using GTN for the prevention of cerebral vasospasm. 125 patients classified as Fisher's Group 2, 3 or 4 were operated on within 72 hours after subarachnoid hemorrhage due to ruptured cerebral aneurysm. 58 patients (GTN group) were treated with continuous intravenous infusions of GTN (0.5-1.0 micrograms/kg/min) for about 2 weeks after their operation, and another 67 patients (control group) were not administered GTN. The frequency of occurrence of symptomatic vasospasm decreased in each GTN group of Fisher's classification, and the severity of angiographic vasospasm also tended to decrease. Especially in patients with severe subarachnoid hemorrhage classified as CT group 3 or 4, symptomatic vasospasm occurred in 11 patients (30.6%) in the GTN group, but in 26 patients (63.4%) in the control group. Regarding the outcome, 10 patients (17.2%) in the GTN group showed poor results or died, as opposed to 22 patients (32.9%) in the control group. This difference was significant. Moreover the GTN group had no cases of mortality due to cerebral vasospasm. These results indicate that GTN can be effective for prevention of cerebral vasospasm and improve the prognosis in patients with serious subarachnoid hemorrhage due to a ruptured aneurysm.

[Automated image processing by PACS as a simple tool for designing craniotomy; synthesis of sagittal reconstructed CT images and cerebral angiograms]

Software has been developed to produce sagittal images of the brain recontracted from axial CT slices and automatically superimpose them on the lateral views of cerebral angiograms. A commercially available system for digitization, processing, display and computer storage of film radiographs (EFPACS-500) was used in the present studies. Axial CT scans are obtained in either 3, 5 or 10mm thicknesses parallel to the base line at the 10 degree angle to the OM line, and processed into the digital storage. Plain skull films and subtracted angiograms, on which two reference points on the same base line for superimposition were marked prior to processing, are also digitized and stored in the optical disk. On each CT slice, the ratio is calculated of a lesion's longitudinal length to the midsagittal distance of the head. By simply adjusting a linear cursor, which is parallel to the base line, to the highest and the lowest levels of the lesion, the sagittal image with the lesion clearly depicted is automatically reconstructed. And on this image an angiogram can be superimposed automatically simply by indicating two reference points on the base line on both images. The resulting images have markedly facilitated simple designing of craniotomy for intracranial lesions by graphically indicating their locations along with cerebral vessels in a lateral view.

Synthesized image processing in clinical neurosurgery

In an effort to achieve efficient image management in clinical neurosurgery utilizing a local image filing system (EFPACS, Fuji Electric Co., Ltd), adequate image-processing and display techniques were developed. One is a method whereby the anatomical location of the thalamic and basal ganglion lesions is determined by automatically superimposing these lesions defined by magnetic resonance imaging (MRI) directly onto the Schaltenbrand-Wahren's human brain atlas. Horizontal, coronal and sagittal MR images are initially obtained based on the intercommissural line and a perpendicular erected on the midcommissural point as the basic reference coordinates. Precise superimposition is accomplished by the use of these reference axes. This imaging technique may offer the potential for help in anatomical identification of small intracranial lesions. Another technique described in the current communication is automated synthesis of two cerebral angiograms. By simply indicating two reference points, nasion and inion, with a cursor on the display screen, two films are automatically superimposed and displayed as a single synthesized image, featuring two different vascular phases simultaneously by a positive(vein)-negative(artery) mode. This technique was applied to patients with complete occlusion of the middle cerebral artery with or without sufficient blood flow through collateral circulation and was found useful in evaluating basic hemodynamics on a single angiographic image.

Automated anatomical localization of small intracranial lesions with image processing based on picture-archiving and communication systems

With the use of a commercially available image-filing system, which had been implemented in the hospital for the purpose of efficient image management in neurosurgical practice, the authors developed image-processing and display techniques to identify anatomical localization of intracranial lesions. It is a method whereby the precise locations of small lesions at thalamus and basal ganglia are determined by automatically superimposing these lesions defined by magnetic resonance imaging directly on images from Schaltenbrand's human brain atlas. This paper describes the method and some illustrative examples of clinical application of this imaging technique.

[Trigeminal neuralgia associated with posterior fossa arteriovenous malformation and aneurysm fed by the same artery. Case report]

A 45-year-old male was admitted for evaluation of left facial pain of 11-years' duration. Fifteen years prior to admission, he had had an episode of subarachnoid hemorrhage. Neurological examination revealed no definite abnormalities except for trigeminal neuralgia involving the left second division of the nerve. Computed tomography scan showed an irregular enhanced lesion involving the lateral aspect of the left cerebellar hemisphere. Vertebral angiograms revealed an arteriovenous malformation (AVM) fed by both the dilated left anterior inferior cerebellar (AICA) and superior cerebellar arteries (SCA) and draining into the superior petrosal and transverse sinuses via three enlarged draining veins. A saccular aneurysm was incidentally visualized at the proximal portion of the dilated AICA. The AVM was successfully extirpated through the left retromastoid craniectomy. The trigeminal nerve was directly compressed both rostrally and caudally at its entry zone by two dilated feeding arteries of the SCA and the AICA. The aneurysm was simultaneously obliterated. The postoperative course was uneventful, and the excruciating facial pain completely subsided. Postoperative angiograms confirmed disappearance of both the AVM and the aneurysm. Posterior fossa AVMs causing trigeminal neuralgia in the literature are reviewed, and the association of the AVM and the aneurysm in the posterior fossa is also discussed.