Search PubMed⌕ Search

Biomedical subjects

G M Nesbit

Publications and source records attributed to G M Nesbit.

30 records · Page 2Linked to original sources
PubMed1996

Traumatic indirect carotid-cavernous fistula: report of two cases.

UNLABELLED: OBJECTIVE AND CLINICAL IMPORTANCE: We present two cases of post-traumatic indirect carotid-cavernous fistulas. Trauma produces the direct type of carotid-cavernous fistula in almost all cases, and recognition that trauma may induce the indirect type has been rarely reported. CLINICAL PRESENTATION: Both patients presented with signs and symptoms of direct carotid-cavernous fistulas, including bruit, proptosis, and chemosis, after trauma to the head. INTERVENTION: The two patients were treated by transarterial embolization, resulting in immediate and permanent occlusion of the fistula. CONCLUSION: Trauma may rarely induce an indirect type of carotid-cavernous fistula. This posttraumatic, indirect carotid-cavernous fistula was, in these two cases, successfully and permanently cured by transarterial embolization because of the large fistulous connection between the branches of the external carotid artery and the cavernous sinus.

Adult↗
PubMed1996

Embolization as treatment for spinal cord compression from renal cell carcinoma: case report.

OBJECTIVE AND IMPORTANCE: Metastatic renal cell carcinoma may involve the vertebrae, resulting in acute spinal cord compression. Embolization has been used to reduce operative blood loss during surgical decompression, but it has not been considered as an alternative that may eliminate the need for open debulking. CLINICAL PRESENTATION: A case is presented of a 30-year-old woman with renal cell carcinoma who developed increasing severe back pain, lower extremity weakness, and sensory loss. Magnetic resonance evaluation revealed a T5 metastasis, resulting in significant spinal cord compression. INTERVENTION: Transarterial embolization was performed with polyvinyl alcohol particles and platinum microcoils. One month after embolization, the patient's lower extremity strength and sensation had improved, and magnetic resonance imaging demonstrated a dramatic response with a significant reduction of cord compression. She deteriorated again 4 months later, and a new sacral mass was embolized. She again improved after treatment. CONCLUSION: This report illustrates that embolization may be used as palliative treatment for spinal cord compression and obviate the need for open surgical decompression.

Adult↗
PubMed1996

Intracranial intraarterial thrombolysis facilitated by microcatheter navigation through an occluded cervical internal carotid artery.

This report covers a series of four patients with acute cervical carotid occlusion and profound neurological deficits who were treated with intracranial intraarterial thrombolysis. All of the patients presented with arm plegia with variable leg involvement and two of them had global aphasia. Angiography identified occlusion of the proximal internal carotid artery (ICA) in each case and intracranial thromboembolus of the supraclinoid ICA and/or its branches. Catheter navigation through the occluded ICA segment was straightforward in three patients and somewhat difficult in one patient with an 80% ICA stenosis. Intraarterial urokinase infusion along with mechanical clot disruption was performed at the clot site in the middle cerebral artery, supraclinoid ICA, and/or anterior cerebral artery. All patients had recanalization of the treated artery after urokinase infusion. Antegrade flow through the ICA was reestablished in two patients, and good collateral filling across the anterior communicating artery was established in the other two. All patients had major pretreatment deficits (mean National Institutes of Health (NIH) Stroke Score 24 +/-4) with significant improvement noted at 3 months posttreatment (NIH Stroke Score 7 +/-6;p=0.03). Two patients made a dramatic early recovery. Postprocedure computerized tomography revealed no abnormality in one and asymptomatic basal ganglia high density from repeated local contrast injections in two patients. On the basis of their findings in this small study group the authors suggest that catheter navigation through a presumably occluded carotid artery is feasible and possibly effective in thrombolytic therapy of intracranial thrombolysis. Further study with clinical trials is necessary to determine the safety and efficacy of this technique.

Adult↗
PubMed1994

Prospective evaluation of extracranial carotid stenosis: MR angiography with maximum-intensity projections and multiplanar reformation compared with conventional angiography.

OBJECTIVE: The purpose of this prospective study was to compare MR angiography of the carotid artery from the aortic arch through the circle of Willis using maximum-intensity projection (MIP) and multiplanar reformation (MPR) images with intraarterial angiography in the depiction of extracranial carotid atherosclerosis. SUBJECTS AND METHODS: The carotid arteries in 20 patients were studied with MR and intraarterial angiography. MR angiography included two-dimensional (2D) time-of-flight (TOF) sequences from the aortic arch through the skull base and three-dimensional (3D) TOF sequences centered at the carotid bifurcation and multiple overlapping thin slab acquisition (MOTSA) from the skull base to above the circle of Willis. Targeted MIP images of the 2D and 3D TOF MR angiograms through each carotid bifurcation were obtained. Last, MPR images of the 3D TOF MR angiograms at the obliquity that showed the greatest stenosis were obtained. All studies were reviewed in a double-blinded fashion by two neuroradiologists. Caliper measurements of MR angiograms and intraarterial angiograms were made by using North American Symptomatic Carotid Endarterectomy Trial criteria. Global MIPs of the aortic arch and common carotid arteries from the 2D TOF MR angiograms and targeted MIPs of the intracranial carotid arteries from the MOTSA MR angiograms were compared with the intraarterial angiogram and graded as normal, mild, moderate, severely stenotic, or occluded. RESULTS: MPR of the 3D TOF MR angiograms was highly correlated with intraarterial angiograms for both observers 1 and 2 (0.94/p < .001, 0.96/p < .001 [Pearson correlation/p value]). No statistically significant difference between 3D TOF MPR and intraarterial angiography was seen with a paired t-test. With an alpha = 0.05 (5% probability of type 1 error), the power to detect a difference as small as +/- 5% stenosis between 3D TOF MPR and intraarterial angiogram was 80% for observer 1 and 90% for observer 2. Although both MIPs of the 2D and 3D TOF MR angiograms showed high Pearson correlation coefficients (0.83, 0.90) with intraarterial angiography, the paired t-test revealed a statistically significant difference in the estimation of carotid stenosis. Both observers thought the global MIPs of the 2D TOF MR angiogram allowed good to excellent visualization of the common carotid arteries. The aortic arch was seen in 70% of patients; most of the missed cases occurred early in our experience, when the 2D axial images were not placed sufficiently inferior to include the arch. No stenosis of the great vessel origins was seen in this study. All four stenoses of the intracranial internal carotid artery identified with intraarterial angiography were seen with the MOTSA MR angiogram but with a tendency to overestimate stenosis. Only one carotid siphon was thought to show severe stenosis on the MR angiogram. Intraarterial angiography showed a 50% stenosis. CONCLUSION: It is possible to image the entire carotid artery from the aortic arch through the circle of Willis with MR angiography in a clinically acceptable time. MPR of the 3D TOF MR angiogram reliably shows the percentage of carotid stenosis with no statistically significant difference compared with intraarterial angiography. The role of MR angiography in showing lesions in the circle of Willis or the aortic arch is promising, but the limited number of tandem lesions in this study makes it difficult to draw any conclusions.

Aged↗
PubMed1991

Multiple sclerosis: histopathologic and MR and/or CT correlation in 37 cases at biopsy and three cases at autopsy.

The authors retrospectively reviewed the cases of 40 patients with biopsy- or autopsy-proved inflammatory demyelination consistent with multiple sclerosis (MS); each patient underwent magnetic resonance (MR) and/or computed tomographic (CT) imaging. In review of the 32 MR and 30 CT examinations, three predominant radiologic patterns were apparent: (a) relatively small homogeneous lesions with no or minimal diffuse enhancement; (b) hypoattenuating lesions on CT scans and hypointense lesions on short-TR MR images, with a contrast material-enhanced, isoattenuating or isointense ring; and (c) lesions that were more infiltrative and ill defined, with mixed attenuation and signal intensity and scattered enhancement. A common radiologic feature was lack of mass effect or edema in white matter surrounding even large lesions. In all but four patients the lesions were classified as active by using both histologic and clinical criteria. Histologically active lesions had various radiologic appearances; however, in all contrast-enhanced studies they demonstrated some form of enhancement. Inactive lesions were homogeneously hypoattenuating on CT scans, hypointense on short-TR MR images, and hyperintense on unenhanced, long-TR MR images.

Adolescent↗
PubMed1989

Spinal cord sarcoidosis: a new finding at MR imaging with Gd-DTPA enhancement.

Three patients with histologically confirmed sarcoidosis with spinal cord involvement were examined with high-field-strength magnetic resonance imaging (1.5 T) before and after the administration of gadolinium diethylenetriaminepentaacetic acid. In addition to intramedullary expansion, areas of patchy, multifocal, parenchymal enhancement and areas of linear peripheral enhancement were seen in all three patients; these findings have not been previously reported and are unusual for other more common spinal cord lesions. This observation led to a correct diagnosis and a limitation of the extent of biopsy in two of the cases. Unfortunately, this enhancement pattern is not specific for sarcoidosis, as the authors have observed similar findings in two cases of biopsy-proved myelitis and multiple sclerosis. The peripheral enhancement is thought to be located in the leptomeninges due to leptomeningeal involvement, which was proved histologically in one case. This pattern of involvement, while not specific, is certainly consistent with and, in the appropriate clinical setting, highly suggestive of sarcoidosis.

Adult↗
PubMed1988

Cholangiocarcinoma: diagnosis and evaluation of resectability by CT and sonography as procedures complementary to cholangiography.

The purpose of this study was to evaluate the usefulness of CT and sonography as procedures complementary to cholangiography in the detection and staging of cholangiocarcinoma. The studies of 42 patients with pathologically proved cholangiocarcinoma and preoperative CT (26 patients), sonography (30 patients), and cholangiography (31 patients) were reviewed blindly and retrospectively. The tumor was shown by CT in 69%, by sonography in 47%, and by cholangiography in 97% of patients. Three radiographic types of cholangiocarcinoma were identified: infiltrating stenotic (69%), bulky exophytic (19%), and polypoid intraluminal (12%). CT correctly staged 54%, sonography 50%, and cholangiography 58% of tumors as resectable (40%) or unresectable (60%). The sensitivities in detecting unresectability with CT, sonography, and cholangiography were 44%, 19%, and 43%, respectively; specificities were 78%, 100%, and 100%, respectively. CT and sonography combined with cholangiography increased the sensitivities to 64% and 50%, respectively. CT and sonography were complementary to cholangiography because they helped determine the extrabiliary extent of these tumors and therefore provided information on resectability.

Adenoma, Bile Duct↗
PubMedDate not supplied

Local thrombolytic therapy for cerebrovascular disease: current Oregon Health Sciences University experience (July 1991 through April 1995).

PURPOSE: This report details experience with local intraarterial or intradural sinus thrombolytic therapy for cerebrovascular thromboembolic occlusions in 40 patients. PATIENTS AND METHODS: Between July 1991 and April 1995, intracranial local thrombolytic therapy with urokinase was used to treat 40 patients with occlusive vascular disease. Twenty-six patients had acute occlusions of the central retinal artery, middle cerebral artery, basilar artery, or combined internal carotid and middle cerebral arteries. Three patients had embolic complications related to cerebral vascular embolization procedures. Five patients were undergoing intracranial angioplasty procedures for occlusive atheromatous disease. Six patients had dural sinus thrombosis. RESULTS: Local intraarterial thrombolytic therapy for acute thromboembolic arterial occlusions resulted in excellent restoration of perfusion in 18 patients, partial restoration of flow in four patients, and no effect in five patients. Fourteen of these patients had excellent clinical outcomes, seven made moderate improvements, and six died. In the two patients with central retinal arterial occlusions, no angiographic or clinical response to thrombolytic therapy could be ascertained. There was no angiographic improvement response from thrombolytic therapy in five patients with primary intracranial atheromatous stenosis, and one patient may have had an embolic complication related to this therapy. Three of six patients with dural sinus thrombosis had clearing of the thrombus and an excellent clinical result. The remaining three with extensive dural thrombosis did not have clearing of the thrombus; one patient became blind, and two patients died. Among the 40 patients treated, significant cerebral hemorrhage occurred after therapy in four. CONCLUSION: Local thrombolytic therapy for thromboembolic occlusive cerebrovascular disease is useful in restoring perfusion of acutely occluded vessels. Further experience is needed to fully identify the most appropriate patients for therapy, dose of thrombolytic agent, timing and length of therapy, and risk factors for hemorrhage.

Adolescent↗
PubMedDate not supplied

Foreign bodies in small arteries after use of an infusion microcatheter.

Over a 31-month period, we performed four neurointerventional procedures after which unexpected foreign bodies were noted in multiple arteries. All four procedures had in common the use of Fastracker-18 infusion microcatheters. Histologically, the intravascular debris looked strikingly similar to the hydrophilic coating on the catheter. An in vitro test mimicking clinical use of the microcatheter revealed that the hydrophilic coating can separate from the catheter. Until the coating is refined to make it more resistant to stripping, it may be advisable to reduce the amount of back-and-forth movement of these microcatheters if they have been positioned through guide catheters with small inner diameters and angled tips.

Aged↗