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Biomedical subjects

C F Dowd

Publications and source records attributed to C F Dowd.

At least 109 records · Page 6Linked to original sources
PubMed1989

Endovascular treatment of scalp arteriovenous fistulas associated with a large varix.

Ten patients with scalp arteriovenous fistulas associated with a large varix (cirsoid aneurysms) were treated with a combination of interventional neuroradiologic procedures. These procedures included transarterial embolization, transarterial embolization followed by surgical excision, and two new methods of treatment of cirsoid aneurysms: transvenous embolization and direct puncture of the fistula for embolization. The embolic materials included liquid adhesive agents, particulate agents, detachable balloons, and wire coils. The embolization was performed to lodge the embolic agents in the fistula or proximal draining vein, not just the feeding vessels. Surgery was performed in two cases to remove a small residual nidus of fistula that could not be completely treated with intravascular embolization. With the use of these forms of treatment, cures were obtained in seven patients, and clinical and angiographic improvement was achieved in three patients. No major morbidity, blood loss, or mortality occurred during the treatment of these patients. The follow-up period ranged from 1 month to 8 years.

Adolescent↗
PubMed1988

MR imaging of brain contusions: a comparative study with CT.

Ninety-eight brain contusions in 17 patients served as a data base for a comparative study of MR and CT for defining brain contusions. MR was the more sensitive technique, detecting 98% of the brain contusions compared with only 56% by CT. CT was slightly better for showing hemorrhagic components, documenting 77% of hemorrhages compared with 71% for MR. The appearance of the contusions on MR was variable, depending on the T1- and T2-weighting of the images and the constituents of the contusions, such as edema, hemorrhage, and encephalomalacia. On MR, hemorrhagic components appeared as high signal on T1-weighted images and as either low or high signal on T2-weighted images, depending on the age of the hemorrhage. The approximate ages of hemorrhagic contusions were often suggested by their appearance on T1- and T2-weighted images. CT is very effective for evaluating acute head trauma, but MR is recommended for documenting brain contusions during the subacute and chronic stages of head injuries.

Adolescent↗
PubMed1987

Thrombosed dialysis grafts: efficacy of intrathrombic deposition of concentrated urokinase, clot maceration, and angioplasty.

Forty-one thrombosed polytetrafluoroethylene hemodialysis grafts in 26 patients were treated by a modified method of fibrinolytic therapy and transluminal angioplasty. The modifications included the use of highly concentrated urokinase, intrathrombic injection of urokinase into mechanically macerated thrombi, use of a crossed two-catheter technique, observation of the patient in the angiography suite during the entire procedure, and transluminal angioplasty to correct underlying stenosis immediately after partial or complete thrombolysis. Lysis was initially successful in 37 (90%) of 41 procedures. Successful treatment, defined as a functional graft for longer than 6 months without intervening surgery, was achieved in 16 (62%) of 26 patients. In comparison with previous transluminal or surgical regimens, this modified method permits marked acceleration of thrombolysis, immediate transluminal angioplasty, and sparing of potential future graft sites.

Angioplasty, Balloon↗
PubMedDate not supplied

Subclavian arteritis and pseudoaneurysm formation secondary to stent infection.

Technically uncomplicated percutaneous angioplasty and stent placement of a left subclavian artery stenosis was performed in a 56-year-old man for treatment of subclavian steal syndrome and vertebrobasilar insufficiency. Six days later the patient was readmitted with Staphylococcus aureus bacteremia and stigmata of septic emboli isolated to the ipsilateral hand. Nine days later he had computed tomography (CT) evidence of a contrast-enhancing phlegmon surrounding the stent. Despite clinical improvement and resolution of bacteremia on intravenous antibiotic therapy, the phlegmon progressed, and at day 21 a pseudoaneurysm was angiographically confirmed. The patient underwent surgical removal of the stented arterial segment and successful autogenous arterial reconstruction. The possible contributory factors leading to stent infection were prolonged right femoral artery access and an infected left arm venous access. Although the role of prophylactic antibiotics remains to be defined, it may be important in cases where the vascular access sheath remains in place for a prolonged period of time.

Aneurysm, False↗
PubMedDate not supplied

Transarterial embolization of vertebral hemangioma.

PURPOSE: The authors retrospectively reviewed their 4-year clinical experience to determine the role of transarterial embolization in the treatment of symptomatic vertebral hemangioma. PATIENTS AND METHODS: Eight patients (age range, 12-56 years) underwent a total of 10 embolization procedures; one patient underwent three procedures. The lesions were located between T-5 and L-5, and all patients presented with pain and symptoms referable to the lower extremities. RESULTS: Embolization was technically successful in all patients, and no complications were encountered. Six of eight patients underwent surgery within 48 hours of embolization; four of the six showed significant clinical improvement immediately after surgery and on follow-up (average, 34 months). Two patients did not improve postoperatively. Two patients initially underwent embolization as the sole therapy. The first refused surgery and did not improve clinically; the second underwent two embolization procedures without clinical improvement and eventually underwent a third followed by surgery, which resulted in clinical improvement. All patients were hemodynamically stable during surgery, and blood loss was not problematic in any patient. CONCLUSIONS: Overall, surgery was an effective treatment for symptomatic vertebral hemangioma and the authors conclude that transarterial embolization of vertebral hemangioma is a safe and efficacious adjunctive procedure to such surgery. However, embolization was not as promising as a sole therapeutic modality in this small group of patients.

Adolescent↗
PubMedDate not supplied

Magnetic resonance imaging of intractable complex partial seizures: pathologic and electroencephalographic correlation.

Prior studies indicate variable usefulness of magnetic resonance imaging (MRI) in the evaluation of patients with complex partial seizures (CPS), but sensitivities as low as 12% have been reported. We analyzed the MRI examinations of 20 patients with medically refractory CPS who later underwent resection of the seizure focus proven by electroencephalography (EEG). MRI studies were correlated with surgical pathology in all patients. Eleven of the 20 CPS patients had mesial temporal sclerosis (MTS). Seven of the 11 (64%) exhibited an MRI abnormality at the site of the EEG-demonstrated histopathologic focus. MRI abnormalities included temporal lobe hypoplasia or atrophy (four patients), and increased signal intensity on long repetition time (TR) sequences (three patients). Four patients had no MRI abnormalities corresponding to the histopathologic focus. Nine of the 20 CPS patients had other abnormalities responsible for the seizures, including astrocytoma, cryptic vascular malformation, hamartoma, polymicrogyria, tuberous sclerosis (forme fruste), arachnoid cyst, and congenital hemiatrophy. No patient had normal MRI studies. Our single most useful MRI sequence was the coronal long TR/dual echo sequence, using cardiac gating and first-order gradient moment nulling to diminish flow-related artifacts that could hinder evaluation of medial temporal lobe structures.

Electroencephalography↗
PubMedDate not supplied

Simultaneous subarachnoid hemorrhage and carotid cavernous fistula after rupture of a paraclinoid aneurysm during balloon-assisted coil embolization.

We describe an iatrogenic perforation of a paraclinoid aneurysm during balloon-assisted coil embolization that resulted in simultaneous subarachnoid contrast extravasation and a carotid cavernous fistula. The causative factors specifically related to the balloon-assisted method that led to aneurysm rupture are discussed as well as strategies for dealing with this complication.

Aged↗
PubMedDate not supplied

Embolization of the meningohypophyseal trunk as a cause of diabetes insipidus.

We present an unusual case of diabetes insipidus occurring after selective embolization of 50% dextrose and pure ethanol into an enlarged left meningohypophyseal trunk (MHT) supplying a dural carotid cavernous fistula. The inferior hypophyseal artery was not opacified during the selective preembolization MHT injection; however, diabetes insipidus developed abruptly a few hours after the procedure. The patient required intranasal 1-deamino-(8-D-arginine)-vasopressin for approximately 3 months, after which his symptoms resolved. The hazards of using liquid embolic agents, especially ethanol, in the cavernous branches of the internal carotid artery should always be borne in mind.

Angiography, Digital Subtraction↗
PubMedDate not supplied

Particulate embolization of the anterior choroidal artery in the treatment of cerebral arteriovenous malformations.

The anterior choroidal artery is commonly recruited to supply arteriovenous malformations in the temporal lobe, basal ganglia, lateral ventricle, and internal capsule. Embolization of this artery is theoretically hazardous owing to its supply to important motor territory, relative lack of collaterals, and small caliber. However, this procedure can be a beneficial adjunct to surgery or radiation in the treatment of arteriovenous malformations. We describe our experience in performing particulate embolization of the anterior choroidal artery in 15 patients (16 procedures). Significant flow reduction was achieved in 14 patients. Two symptomatic and two asymptomatic complications arose, including permanent hemiparesis in one patient.

Adolescent↗
PubMedDate not supplied

Management of vascular perforations that occur during neurointerventional procedures.

This article describes a number of treatment strategies for the management of perforations that occur during neurointerventional procedures. During the past 5 years, we have performed over 1200 endovascular procedures to treat vascular disorders involving the brain and spinal cord (400 cerebral arteriovenous malformations, 230 tumors, 197 carotid cavernous fistulas, 183 aneurysms, 130 dural fistulas, 80 spinal arteriovenous malformations, 18 vein of Galen aneurysms, and 20 cases of vasospasm). Fifteen patients (1.1%) sustained a vascular perforation as a direct result of these procedures. Among these 15 patients, indications for endovascular treatment were six symptomatic arteriovenous malformations, two spinal cord arteriovenous malformations, two cavernous sinus dural fistulas, one transverse sinus fistula, one case of vasospasm following subarachnoid hemorrhage, one direct carotid cavernous fistula, one vein of Galen malformation, and one ruptured basilar artery aneurysm. The vascular perforations were grouped into three probable mechanisms: mechanical perforation of a normal vessel (six patients), mechanical disruption of a dysplastic vessel or aneurysm (five patients), and fluid overinjection (four patients). Treatment of the perforations included immediate reversal of anticoagulants (12 patients) and direct closure of the perforation site with coils (five patients). In addition, closure of the intravascular compartment adjacent to the perforation was achieved with coils (six patients), liquid adhesives (four patients), balloons (two patients), or particles (two patients). In two patients a detachable balloon was placed transiently across the perforation site for several minutes, deflated, and removed when no further extravasation was noted. Five patients were started on anticonvulsant therapy, two of whom have had a new onset seizure related to the perforation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Transarterial platinum coil embolization of carotid-cavernous fistulas.

Of the 227 embolization procedures performed by our neurointerventional section for symptomatic carotid-cavernous fistulas over the past 10 years, five involved placement of platinum coils in the cavernous sinus from a transarterial route. In four patients, prior transarterial balloon procedures had failed to produce fistula closure. In the fifth patient, with Ehlers-Danlos syndrome, a prior transvenous embolization attempt was unsuccessful. In three patients, complete closure of the carotid-cavernous fistula was achieved with preservation of the parent artery. In one patient, the earliest treated, a portion of a platinum coil projected through the fistula into the parent artery. To eliminate the risk of clot formation and distal embolization, internal carotid occlusion was performed and tolerated without deficits. In the last patient, closure of the anterior drainage was achieved, but complicated by distal migration of the platinum coils with transient aggravation of ocular symptoms. Attempts to occlude the remaining cortical drainage were unsuccessful with platinum coils; therefore, a balloon was used to obliterate the small remaining fistula. Transarterial platinum coil embolization is an alternative treatment for symptomatic carotid-cavernous fistulas that cannot be closed successfully by other embolization techniques. The development of shorter, more thrombogenic, detachable or retrievable coils may make this technique more promising in the future.

Adult↗
PubMedDate not supplied

Multiple dural arteriovenous fistulas of the cranium and spine.

Dural arteriovenous fistulas are acquired lesions that usually involve the dura around the cavernous sinus. The transverse, sigmoid, and superior sagittal sinuses may be affected occasionally. With the exception of bilateral cavernous sinus dural arteriovenous fistulas, the simultaneous occurrence of dural arteriovenous fistulas at two locations is rare. Among 105 patients evaluated for dural arteriovenous fistulas, we identified seven patients with fistulas at two sites. The age of the patients ranged from 27 to 74 years. Presentation was related to hemorrhage in three patients, loss of vision in four, and a bruit and headaches in one. Patients were treated with combined surgical and endovascular techniques. All treated lesions were completely closed with no mortality or permanent morbidity. The presence of multiple fistulas must be considered in patients being evaluated for dural arteriovenous fistulas. Patients with multiple fistulas usually present with life-threatening hemorrhages or acute neurologic decline; the risk factor for hemorrhages, including those related to venous outflow obstruction, is high in patients with multiple dural arteriovenous fistulas.

Adult↗
PubMedDate not supplied

Aneurysms of the petrous portion of the internal carotid artery: results of treatment with endovascular or surgical occlusion.

Seven patients with symptomatic aneurysms involving the petrous segment of the internal carotid artery were treated by endovascular techniques (six patients) or surgical ligation (one patient). Patients' ages at the time of treatment ranged from 7 to 62 years (mean, 30 years). The presenting symptoms were pain (seven patients), eighth nerve dysfunction (three patients), seventh nerve dysfunction (one patient), fifth nerve dysfunction (two patients), and bruit (one patient). Two patients, ages 7 and 19, respectively, presented with giant, partially thrombosed petrous aneurysms and had hemiatrophy of the body ipsilateral to the side of the aneurysm. Only one patient had a history of trauma; aneurysms in the remaining patients were presumed to be congenital in origin. In one patient with a saccular aneurysm, a balloon could be navigated into the aneurysm, obliterating it but preserving the parent artery. The remaining six patients had fusiform aneurysms with intraluminal thrombus and underwent proximal occlusion (four patients) or trapping procedure (two patients). In all patients, symptoms were alleviated after thrombosis of the aneurysm. The only complication was a transient visual loss in a hypercoagulable patient, occurring after carotid occlusion. Petrous carotid aneurysms can produce a wide clinical spectrum of signs and symptoms in younger patients; these aneurysms frequently are fusiform and contain chronic thrombus. They can be treated effectively by endovascular or surgical occlusive procedures.

Adolescent↗
PubMedDate not supplied

Transfemoral venous embolization of vein of Galen malformations.

Three infants with vein of Galen malformations, all presenting with congestive heart failure, underwent a total of five embolization procedures that employed a percutaneous transfemoral venous approach to catheterize the vein of Galen. In one instance, direct retrograde catheterization of feeding arterial pedicles to the vein of Galen and embolization of the fistulous connections was achieved via this route. The indications for transfemoral venous treatment included persistent symptoms despite transarterial and transtorcular embolization in one patient, an unsuccessful transarterial embolization attempt (complicated by catheter fracture) in another, and the inadvisability of transarterial embolization because of an excessive number of feeding arteries in a third. Complete obliteration of the malformation was achieved in one patient and significant flow reduction in the other two. Vein of Galen perforation with the catheter tip complicated one procedure. All three patients were stable after clinical follow-ups (9-12 months). The transvenous route to the vein of Galen can be undertaken from a transfemoral approach, obviating surgical exposure of the torcular Herophili. In addition, we introduce the concept of direct retrograde catheterization of the feeding arteries to the vein of Galen malformation by a transfemoral venous approach, a procedure that has not been reported previously.

Cerebral Veins↗
PubMedDate not supplied

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.

Adolescent↗