Randomized comparison of Guglielmi detachable coils and cellulose acetate polymer for treatment of aneurysms in dogs.

BACKGROUND AND PURPOSE: Endovascular treatments for aneurysms are being used more frequently in patients in the absence of a large body of information on their histopathological effects. This study determined the efficacy and histopathological effects of treatment of experimental aneurysms with Guglielmi detachable coils (GDC) or cellulose acetate polymer (CAP). METHODS: Fourteen dogs had 13 terminal and 30 sidewall aneurysms created with venous pouches sutured to the cervical carotid arteries. Two weeks later, dogs had angiography followed by randomization to no treatment (n=2) or to aneurysm occlusion with GDC (n=4) or CAP (n=6). Two months later, angiography was repeated, animals were killed, and aneurysms were excised, fixed, photographed, and examined by light and electron microscopy. RESULTS: Two dogs were excluded because of common carotid artery occlusion at 2-week angiography. There were 11 terminal and 16 sidewall aneurysms available for treatment. The rate of spontaneous thrombosis of untreated aneurysms was 0% (0/5). Treatment with GDC showed complete terminal and sidewall aneurysm obliteration rates of 33% (1/3) and 80% (4/5), respectively. Greater than 90% occlusion occurred in the remaining cases. There were no parent or branch artery occlusions. Treatment with CAP showed complete terminal and sidewall aneurysm obliteration rates of 20% (1/5) and 0% (0/5), respectively, and incomplete sidewall aneurysm obliteration in 1 of 5 cases. Aneurysms reformed at 2 months in 2 of 5 terminal and 1 of 5 sidewall cases. There were parent or branch artery occlusions with CAP in 2 and 4 cases, respectively. The rate of aneurysm occlusion was significantly lower and the rate of arterial occlusion significantly higher with CAP than with GDC (P<.05). Histopathology showed complete endothelialization across the orifice of the aneurysm successfully treated with CAP, whereas aneurysms treated with GDC were significantly more likely to show fresh or organizing thrombus without complete endothelialization (P<.05). CONCLUSIONS: It is concluded that both treatments have limitations. Complete packing of aneurysms with GDC obliterates the aneurysm, but endothelialization does not always occur within 2 months. There are substantial problems with CAP. It is thrombogenic and carries a higher risk of causing arterial thrombosis. Even if an aneurysm is successfully obliterated initially with CAP, the CAP may disappear, leaving the aneurysm completely untreated.

Embryological basis of some aspects of cerebral vascular fistulas and malformations.

The literature on the formation of cerebral veins is reviewed to obtain a better understanding of some cerebrovascular anomalies. Clinical observations such as the entry of the superior ophthalmic vein into the cavernous sinus through the inferior rather than the superior orbital fissure, the relative infrequency of middle cerebral vein backflow in the presence of an extensive cavernous fistula, and the relative infrequency of hemorrhage in relation to the inferior petrosal fistula all relate to the persistence of an older venous pathway. The frequent occurrence of hemorrhage in association with the superior petrosal sinus fistula and the frequent failure of the superior petrosal sinus to connect to the cavernous sinus similarly have an embryological explanation. The frequent association of the vein of Galen aneurysm and an absent or deformed straight sinus probably relates to the time at which the paired internal cerebral veins fuse into one channel. It is speculated that the origins of cerebral venous malformations (CVMs) and arteriovenous malformations (AVMs) probably relate to sequential formation and absorption of surface veins, which occur in human embryonic development mainly in the 40- to 80-mm length interval, although persistent AVM growth is possible even after birth. The frequent absence or anomaly of the middle cerebral vein and its failure to communicate with the cavernous sinus in the presence of both CVMs and AVMs are linked to the late development of that vein and to its even later connection to the cavernous sinus.

Cerebral venous malformation-arteriovenous malformation transition forms.

Three cases of cerebral venous malformation (CVM) are presented to demonstrate the triad that characterizes CVM: abnormal surface venous drainage, a "star-cluster" system of deep collecting veins, and a deep draining vein. Four other cases are introduced that illustrate this triad and show an additional feature, namely arterial fistulization; these cases represent arteriovenous malformations (AVMs). A final case demonstrates a CVM within an AVM. Both of these structures have a common draining vein and an identical venous core. On the basis of the cases described and of others less suitable for illustration, it is postulated that an AVM is a fistulized CVM and that both relate to a failure in the development of the cortical venous mantle. This proposition is based on the authors' observations and their assessment of the "best possible fit."

Periventricular heterotopia and epilepsy.

We report a family with nodular subependymal masses of heterotopic gray matter occurring in six members in four generations. Only female members of the family are affected, and there is a high rate of spontaneous abortion, consistent with X-linked dominant inheritance, and lack of viability in affected males. Both in this family and in sporadic cases of subependymal heterotopias there is a high frequency of convulsive disorders, suggesting that epilepsy may be the major clinical manifestation of this developmental defect.

Positron emission tomographic evaluation of patients with head and neck cancer undergoing occlusion and removal of the carotid artery.

We used positron emission tomography (PET) to evaluate cerebral metabolic changes in five patients who underwent resection of the internal carotid artery (ICA) for malignant tumors of the head and neck. These patients received a thorough clinical neurologic examination as well as neuroradiologic evaluation, including computed tomography (CT), magnetic resonance imaging (MRI), and PET of the head, before and after balloon occlusion of the ICA. All five were free of cerebral or peripheral vascular disease. In addition, each patient was evaluated with an electroencephalogram (EEG) before and during the balloon occlusion for signs of ischemic changes. No abnormalities were noted on clinical neurologic examination, CT, MRI, or EEG, either before or after occlusion, and excision of the ICA. The PET examination showed a mean preoperative metabolic rate of 7.52 mg of glucose/min/100 gm of brain tissue and a mean postoperative rate of 6.32 mg/min/100 gm of brain tissue; these values were within the normal range of 5.00 to 9.00 mg of glucose/min/100 gm of tissue observed at this center. Only one subject showed asymmetry of glucose metabolism; this subject had received radiation treatment to one side of the brain after the initial PET evaluation. The results of this study support our clinical experience with occlusion and resection of the ICA in patients with head and neck tumors that in the past have been considered inoperable.

Evaluation of radiographs developed by a new ultrarapid film processing system.

The image quality of radiographs developed by a new ultrarapid processor was evaluated to determine if faster processing causes degradation in the image. The processor used was the Konica Super-Rapid SRX-501 model. Two films designed for this processor (Konica MGH-SR and MGL-SR) were processed in 45 sec and were compared with standard rapid processing in 90 sec of corresponding conventional films (Kodak TMG and OC). Rare-earth screens (Kodak Lanex Regular and Lanex Medium) used with the new and conventional films interleaved during angiographic studies or for phantom images were assessed for image quality. The basic imaging properties of the screen-film systems were examined by measuring (1) Hurter and Driffield curves, (2) modulation transfer functions by using the slit method, and (3) noise Wiener spectra. Subjective clinical assessment showed that the images obtained with ultrarapid processing were acceptable, with increased contrast and graininess. Hurter and Driffield curve measurements confirmed higher gradients. Modulation transfer function measurements were the same as for the conventional films. Noise Wiener spectrum measurements showed a 10% increase in noise for MGH-SR vs TMG film and a 30% increase for MGL-SR vs OC film. We conclude that acceptable image quality can be obtained using ultrarapid processing, with processing time approximately 60% that of conventional rapid processing. Potential applications include all areas in which rapid availability of the radiograph for interpretation is important. Although the processor studied was the first of its kind available, our evaluation indicates that the technology is available for a new class of ultrarapid processors.

Internal carotid artery hypoplasia.

Hypoplasia of the carotid arteries is a rare congenital anomaly which when clinically symptomatic presents as cerebral ischemia or hemorrhage. Patients with this anomaly commonly have associated variations of the circle of Willis, an increased incidence of intracranial aneurysms and extensive networks of collateral vessels to accommodate the diminished carotid flow. Carotid artery hypoplasia should not be confused with other conditions which may have a similar appearance such as arterial dissection, vasculitis, and tubular fibromuscular hyperplasia.

Paraganglioma metastatic to the cervical spine.

Paragangliomas are usually benign tumors which may be locally invasive. Only 10% of these tumors are malignant. When metastases occur the most common sites are lung, liver and bone. When bony metastases occur the spine is a common site. In the present case cervical spine metastases with resultant bony encroachment and epidural extension of tumor with cord compression was diagnosed with myelography and CT.

Experimental vasospasm: experiences with a canine model and failure of naloxone therapy.

Experimental vasospasm was studied in a canine model utilizing subarachnoid injection of autologous blood. Alterations in the size of the basilar artery were noted angiographically. Naloxone, an opioid receptor antagonist, has been reported to have a beneficial effect on neurological dysfunction secondary to cerebral ischemia. No significant change in the diameter of the basilar artery was noted in dogs either with or without spasm when treated with naloxone. We have concluded that naloxone has no detectable vasodilatory effect on the cerebral arteries of dogs.

Spontaneous intracerebral hematoma in carotid-cavernous fistula. Report of three cases.

Spontaneous intracerebral hematoma associated with carotid-cavernous fistula is rare. Three new cases are presented. In each, the hemorrhage originated in the vicinity of localized intracranial venous engorgement, as demonstrated by cerebral angiography. Rupture of one or several of the distended venous channels from increased back-flow is postulated as the etiology of the intraparenchymal hematomas.