Venous infarction of the spinal cord resulting from dural arteriovenous fistula: MR imaging findings.

Three patients with spinal dural arteriovenous fistula presented with acute and/or progressive myelopathy. The thoracic cord was focally enlarged and poorly defined on MR images in two of the patients. One individual showed focal cord atrophy, and one demonstrated abnormal intrathecal vessels. In all patients MR studies revealed cord enhancement after IV administration of gadopentetate dimeglumine. The MR findings are believed to represent disruption of the blood-cord barrier associated with cord ischemia and/or infarction, which, in turn, is caused by venous stasis resulting from the fistula. The diagnosis in each case was confirmed by the combined results of myelography, spinal arteriography, and surgery. Surgical excision or embolization of the fistula produced a poor return of lost function but an arrest in the progression of paresis. One of the patients had constant severe back and leg pain postoperatively, and a follow-up MR study 5 months after surgery showed focal atrophy and persistent enhancement of the thoracic cord. The patient with preoperative focal cord atrophy had an MR examination 1 year prior to surgery, which revealed enhancement of the cord similar to that seen on the immediate preoperative MR study. This patient also had severe pain in the back and lower extremities preoperatively, which accompanied her progressive paraparesis. It is believed that long-standing enhancement of the spinal cord in patients with dural arteriovenous fistula probably results from chronic progressive venous ischemia, which may be irreversible and cause pain of a central type.

The radiologic assessment of trigeminal neuropathy.

The clinical and radiologic records of 76 patients with trigeminal neuropathy and an abnormal imaging study (CT and/or MR) were analyzed retrospectively. The trigeminal nerve (cranial nerve V) was divided into proximal (brainstem, preganglionic, gasserian ganglion, and cavernous sinus) and distal (extracranial V1, V2, and V3) segments. Lesions were organized according to segments and correlated with the type and distribution of clinical symptoms or signs. The purpose of the study was to (1) determine the efficacy of clinical localization of cranial nerve V lesions, (2) compare CT and MR for cranial nerve V imaging, (3) develop an MR protocol for effective cranial nerve V imaging, and (4) construct a differential diagnosis by anatomic segment for lesions of cranial nerve V. Clinical localization was found to be extremely inaccurate. CT was not as sensitive as MR for lesions involving the basal cisterns and skull base and will not detect the most common brainstem lesions (small infarcts and multiple sclerosis plaques). The MR protocol developed does not rely heavily on clinical localization. On the basis of lesions found in this series, a differential diagnosis by segment was developed. Patients with cranial nerve V symptoms should undergo MR imaging according to the protocol provided in this article. CT is not as effective as MR in imaging some cranial nerve V segments. Clinical localization is inaccurate.

The radiologic assessment of trigeminal neuropathy.

The clinical and radiologic records of 76 patients with trigeminal neuropathy and an abnormal imaging study (CT and/or MR) were analyzed retrospectively. The trigeminal nerve (cranial nerve V) was divided into proximal (brainstem, preganglionic, gasserian ganglion, and cavernous sinus) and distal (extracranial V1, V2, and V3) segments. Lesions were organized according to segments and correlated with the type and distribution of clinical symptoms or signs. The purpose of the study was to (1) determine the efficacy of clinical localization of cranial nerve V lesions, (2) compare CT and MR for cranial nerve V imaging, (3) develop an MR protocol for effective cranial nerve V imaging, and (4) construct a differential diagnosis by anatomic segment for lesions of cranial nerve V. Clinical localization was found to be extremely inaccurate. CT was not as sensitive as MR for lesions involving the basal cisterns and skull base and will not detect the most common brainstem lesions (small infarcts and multiple sclerosis plaques). The MR protocol developed does not rely heavily on clinical localization. On the basis of lesions found in this series, a differential diagnosis by segment was developed. Patients with cranial nerve V symptoms should undergo MR imaging according to the protocol provided in this article. CT is not as effective as MR in imaging some cranial nerve V segments. Clinical localization is inaccurate.

Transarterial occlusion of solitary intracerebral arteriovenous fistulas.

Congenital solitary arteriovenous fistulas unassociated with arteriovenous malformations are rare. Five patients with this condition were treated by endovascular procedures: three by transarterial balloon occlusion and two by coil and silk suture embolization. Of the three patients treated by balloon occlusion, complete angiographic obliteration was achieved in two, and one patient had subtotal occlusion resulting from proximal balloon placement. Two of these patients subsequently underwent surgical excision without incident. There were no complications. Two patients were treated with a combination of platinum coils and silk suture embolization, which resulted in complete angiographic obliteration in both. There was one asymptomatic complication consisting of a coil migrating through the fistula and lodging in the lung. While detachable balloons have advantages in allowing test occlusion prior to detachment, the traction required for detachment can limit accurate deposition and place the feeding arteries under undue stretch. Coil and silk suture embolization enable more precise deposition and are probably the agent of choice for closure of solitary arteriovenous connections within the central nervous system.

Transvenous embolization of dural fistulas involving the cavernous sinus.

Because of the risks associated with arterial embolization of cavernous dural fistulas, we have sought an alternative method to promote fistula closure. Thirteen patients underwent transvenous embolization as a treatment for symptomatic cavernous dural fistulas. All procedures were performed from a femoral vein access through the inferior petrosal sinus or basilar plexus. In five patients the inferior petrosal sinus was not angiographically demonstrable; however, embolization was still possible through this route in two patients. The embolic agents used were detachable balloons in one patient, coils alone in five, coils and liquid adhesives in four, coils plus silk sutures in one, silk sutures alone in one, and liquid adhesives alone in one. Nine patients had follow-up angiograms, which showed complete obliteration of the fistulas and complete resolution of related symptoms. One patient had complete resolution of clinical symptoms but refused follow-up angiography. Another patient had 50% decrease in fistula flow on the follow-up angiogram and improvement in clinical symptoms. Two patients had complete fistula obliteration after embolization and progressive improvement in symptoms but follow-up angiograms had not been obtained. Follow-ups ranged from 1 to 97 months (mean, 15 months). Two complications were related to this treatment. An embolic stroke followed transient placement of a balloon in the internal carotid in one patient, and a second patient developed transient visual loss when the venous outflow pathways were occluded before fistula closure. The fistula was immediately closed with complete recovery of vision. With recent advances in microcatheter and embolic agent technology, transvenous closure of cavernous dural fistulas is now possible.(ABSTRACT TRUNCATED AT 250 WORDS)

Transvenous embolization of dural fistulas involving the transverse and sigmoid sinuses.

Eleven patients with dural fistulas involving the transverse and sigmoid sinuses were treated by transvenous embolization with coils or liquid adhesives. Seven patients underwent preoperative embolization of the external supply followed by direct surgical exposure of the sinus: liquid adhesives were used in four patients and coils in the remaining three. Four of these patients had complete obliteration of their fistulas and there was 95% reduction in the remaining three. Four patients had transvenous placement of coils from a transfemoral approach. In three, the ipsilateral sigmoid sinus was thrombosed and a contralateral approach across the torcular herophili was used. Coils were used in all four patients; one patient also had liquid adhesives placed within the sinus. Complete cure was achieved in one patient, 95% reduction in another, and 50% and 40%, reductions in the remaining two. Two transient complications occurred, one related to venous occlusion secondary to liquid adhesives and another related to transient occlusion of the vestibular aqueduct. Obliteration of dural fistulas involving the transverse and sigmoid sinuses can be achieved by placement of embolic material within the involved sinus from a transvenous approach; both coils and liquid adhesives can achieve this goal.

Treatment of dural fistulas involving the deep cerebral venous system.

Eight patients with dural arteriovenous fistulas involving the deep cerebral venous system were treated by a combination of preoperative embolization, intraoperative embolization, and/or surgical excision. All eight patients were men 30-71 years old (mean age, 48.5). The presenting symptoms were hemorrhage in four patients (two subarachnoid, one intraventricular, and one parenchymal), stroke in two patients, and severe chronic headaches in two patients. Four patients were treated and cured by preoperative embolization of external carotid feeding vessels followed by direct intraoperative placement of liquid adhesives into the fistula site. Two patients underwent preoperative embolization followed by surgical interruption of feeding vessels to the fistula. Both patients had persistent fistulas and were subsequently treated by intraoperative embolization with liquid adhesives. One patient was cured and the second had 95% reduction in fistula size. The remaining two patients had surgical excision of the fistula, one in combination with preoperative embolization. Both were completely cured. Two patients developed hydrocephalus after placement of liquid adhesive into the involved vein of Galen and were successfully treated with placement of ventriculoperitoneal shunts. Follow-up periods ranged from 7 to 21 months (mean, 14). We found that patients with dural arteriovenous fistulas could be treated effectively through a combination of neuroradiologic and surgical intervention.

Direct puncture of the proximally occluded internal carotid artery for treatment of carotid cavernous fistulas.

Three patients with symptomatic carotid cavernous fistulas (CCFs) characterized by complete occlusion of the proximal internal carotid artery were treated by percutaneous puncture and embolization. Two patients had CCFs associated with traumatic dissections of the internal carotid artery and were treated initially with trapping procedures. Both patients had persistent symptoms related to the CCF and underwent additional surgical procedures (ophthalmic artery ligation and intraoperative embolization) without improvement. The third patient had traumatic occlusion of the internal carotid artery. After direct percutaneous puncture of the carotid artery above the occlusion, a catheter was advanced into the petrous internal carotid artery. Balloons (one case) or coil emboli (two cases) were placed into the cavernous sinus to produce CCF closure. There were no complications from this procedure. Direct puncture of the carotid artery is an alternative treatment for patients lacking safe access for CCF embolization.

Embolization of branches arising from the cavernous portion of the internal carotid artery.

Seven patients with vascular disease (four with cavernous and two with transverse sinus dural fistulas and one with a facial arteriovenous malformation, all supplied primarily from cavernous branches of the internal carotid artery) underwent subselective catheterization and embolization. Ten branches were catheterized (seven meningohypophyseal trunks and three inferolateral trunks) and eight branches were embolized. The embolic agents were as follows: polyvinyl alcohol particles in five, hypertonic glucose in two, and liquid adhesive in one. All four cavernous sinus dural fistulas were occluded after embolization. In the two transverse sinus fistulas, the goal of embolization was to obliterate the tentorial supply prior to surgery. This goal was achieved in both cases. In the remaining patient, who had a large facial arteriovenous malformation and recurrent epistaxis, the embolization obliterated the cavernous supply to the nasal cavity and the patient remains hemorrhage-free. Despite one complication, which occurred in the first case when a thrombus formed and dislodged, resulting in an embolic stroke, this study shows that subselective catheterization and embolization can obliterate lesions of the branches arising from the cavernous internal carotid artery.

Permanent inflation of detachable balloons with a low-viscosity, hydrophilic polymerizing system.

A polymer system was developed for use in permanent inflation of detachable balloons, to avoid long-term reliance on the integrity of balloon shells or valve mechanisms. This system is based on 2-hydroxy-ethyl methacrylate (HEMA) as the monomer, in combination with a cross-linking agent and a water-soluble curing system. The low-viscosity, hydrophilic mixture can be exchanged through a small-bore catheter into a detachable balloon and polymerizes in 40-60 minutes at body temperature. Partially polymerized HEMA can cause vascular occlusion; hence, careful timing of balloon detachment is required. The evolution of the radiographic appearance of HEMA-filled balloons is predictable. The balloons remain radiopaque on plain radiographs as long as the balloon shell and valve mechanisms are competent. After rupture of the shell or failure of the valve mechanism, the balloons become invisible on plain radiographs but remain hyperattenuating on computed tomography scans.

Arteriovenous fistula of the internal maxillary artery: treatment with transarterial embolization.

Six patients with arteriovenous fistulas of the internal maxillary artery were treated with transarterial embolization. The patients ranged in age from 19 to 47 years, with a mean of 26.5 years. Each had a lifelong history of symptoms suggestive of a congenital origin of symptoms. There was no history of trauma. The most common initial symptoms were bruit (83%), pulsatile mass (67%), and pain (50%). In one patient prior surgical ligation of the external carotid artery had been attempted, but it led to aggravation of headaches. All patients were treated with placement of a detachable balloon at the fistula site. In one patient the balloon migrated through the fistula, which was retreated with coils. Complete obliteration of the fistula was achieved in all patients. The follow-up ranged from 2 months to 10 years, with a mean of 5.2 years. Congenital arteriovenous fistulas of the internal maxillary artery are rare and can be treated effectively with transvascular techniques.

Transvenous embolization of direct carotid cavernous fistulas.

Of 165 cases of direct carotid cavernous fistula, 14 (8.5%) were treated from a transvenous approach. Twelve of these were treated through the inferior petrosal sinus and one through the superior ophthalmic vein. In one patient, both approaches were used. The embolic agents were as follows: five patients had balloons only, four patients had minicoils alone, three patients had coils and liquid adhesives, one had balloons and coils, and one had balloons and liquid adhesives. Among the patients who were treated from a transvenous approach, three had an occluded carotid artery caused by trauma, nine failed transarterial balloon attempts, and one had a prior trapping procedure. In the remaining patient, who had Ehlers-Danlos syndrome, a transarterial approach was judged to be too dangerous. This patient suffered a fatal pontine hemorrhage after subtotal transvenous occlusion of the carotid cavernous fistula with diversion of flow into cortical veins. Another complication occurred when the inferior petrosal sinus was perforated during catheterization, causing a small subarachnoid hemorrhage. The tear was immediately closed with minicoils, and surgical exposure and embolization resulted in complete cure. Of the remaining 12 patients treated, 11 were completely cured and one showed angiographic and clinical improvement. Transarterial balloon embolization remains the procedure of choice in the treatment of symptomatic carotid cavernous fistulas; however, transvenous embolization is an alternative when the arterial route fails.

The masticator space: the influence of CT scanning on therapy.

The masticator space is an important suprahyoid tissue compartment bounded by the superficial layer of the deep cervical fascia, enclosing the ramus of the mandible plus the masseteric and pterygoid muscles. Pathology of this space has been clinically difficult to diagnose and treat. Twenty-five patients with either tumor or infection involving the masticator space who underwent CT scanning were evaluated retrospectively. Ten patients had infection and 15 had tumor. CT was influential in directing appropriate biopsies or therapy in 24 of 25 patients. It misguided therapy once. The gross anatomic and CT appearance of the normal and the diseased masticator space is described along with pictures of representative cases. A discussion is given of the advantages, disadvantages, and pitfalls of computerized tomography of the masticator space.

Infection and tumor of the masticator space: CT evaluation.

The masticator space is a distinct deep facial space, bounded by the superficial layer of deep cervical fascia and containing the four muscles of mastication and the ramus and posterior body of the mandible. Trismus often complicates evaluation of masticator space disease. However, computed tomography (CT) clearly delineates the normal and pathologic anatomy of this region. The CT appearance of the masticator space was demonstrated in a retrospective review of 32 patients with either infection or tumor involving this space. Masticator space infections were found to have characteristic CT appearances and patterns of spread. CT was especially useful in differentiating inflammation from frank abscess, detecting mandibular osteomyelitis, and directing surgical drainage to the precise deep-tissue space involved. In cases of tumor, the primary utility of CT was in defining tumor extent accurately and in helping to assess resectability and determine radiation therapy ports.

Digital subtraction coronary angiography using high-pass temporal filtration: a comparison with cineangiography.

Selective coronary angiograms were obtained using a real-time high-pass temporal filtration digital subtraction technique with videotape storage and display and compared to simultaneously recorded 35-mm cineangiograms for 32 stenotic lesions in 15 patients. Both methods were evaluated by three independent observers using caliper measurement of percent diameter reduction for each lesion. There was a good correlation between the two imaging methods for individual observers, though considerable variability was seen, r = .73, standard error of estimate (SEE) = 9.1%. The average severity of stenosis and the interobserver variability were similar between methods. This digital subtraction technique for selective coronary angiography compares favorably with a conventional film-based technique for evaluation of coronary stenoses and offers advantages of real-time image processing, limited tolerance to patient motion, and relatively small digital memory requirements. In addition to further improvements in image quality, more objective computer-aided scoring methods are needed to reduce the variability in lesion analysis.

Real-time digital angiocardiography using a temporal high-pass filter.

A temporal high-pass filtration technique for digital subtraction angiocardiography was studied, using real-time digital studies performed simultaneously with routine cineangiocardiography (cine) for qualitative image comparison. The digital studies showed increased contrast and suppression of background anatomy and also enhanced detection of wall motion abnormalities when compared with cine. This digital technique is compatible with panning the image intensifier during an injection. The digital images are comparable with, and in some cases better than, cine images. Clinical efficacy of this digital technique is currently being evaluated. Real-time display, as well as potential reductions in radiation and contrast material doses, may make digital angiocardiography an attractive technique.