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Biomedical subjects

G H Zoarski

Publications and source records attributed to G H Zoarski.

At least 19 recordsLinked to original sources
PubMed2001

An intracranial aspergilloma with low signal on T2-weighted images corresponding to iron accumulation.

We present a case of cerebral aspergillosis in an immunocompetent patient. The MRI signal characteristics were compared with the histologic findings. Irregular low-signal zones were demonstrated between the wall of the abscess and the central necrosis on T2-weighted images; the pathology specimen revealed concentrated iron in these transitional zones but no hemosiderin. Iron is an essential element for the growth of fungal hyphae. The low-signal zones may represent the areas where there was active proliferation of aspergillus, and the unique location of the low signal may be a helpful imaging characteristic for the diagnosis of an aspergillus abscess.

Adult↗
PubMed2001

Vertebral artery pseudoaneurysm complicating posterior C1-2 transarticular screw fixation: case report.

BACKGROUND: Vertebral artery injury during posterior C1-2 transarticular screw fixation occurs in approximately 3% of patients and may remain asymptomatic or result in arteriovenous fistulae, occlusion, narrowing, or dissection of the vertebral artery, and lead to transient ischemic attacks, stroke, or death. CASE DESCRIPTION: This is the first report of a pseudoaneurysm resulting from damage to the vertebral artery during the procedure. This 31-year-old male underwent posterior C1-2 transarticular screw fixation for unstable os odontoideum. Injury to the left vertebral artery occurred while the hole for the left screw was being drilled. Temporary control of bleeding with local pressure was followed by immediate postoperative angiography that revealed a left vertebral artery pseudoaneurysm. Although the patient remained asymptomatic, therapeutic anticoagulation was instituted 6 hours postoperatively. Increasing size of the pseudoaneurysm was noted on routine follow-up angiography 4 weeks later. Endovascular occlusion of the pseudoaneurysm and left vertebral artery, with preservation of vertebrobasilar flow through the right vertebral artery, was accomplished without neurological consequence. CONCLUSIONS: Vertebral artery pseudoaneurysm complicating posterior C1-2 transarticular screw fixation may be effectively treated with endovascular approaches.

Adult↗
PubMed2001

A clinical comparison of the safety and efficacy of MultiHance (gadobenate dimeglumine) and Omniscan (Gadodiamide) in magnetic resonance imaging in patients with central nervous system pathology.

RATIONALE AND OBJECTIVES: The safety and diagnostic efficacy of MultiHance (gadobenate dimeglumine) in the central nervous system (CNS) were evaluated in a double-blind, multicenter, phase III clinical trial. METHODS: Two hundred five patients highly suspected of having a CNS lesion (by previous imaging exam) were enrolled at 16 sites in the United States. Patients were randomized to one of three incremental dosing regimens. Magnetic resonance imaging with Omniscan (gadodiamide) at doses of 0.1 and 0.3 mmol/kg was compared with MultiHance (gadobenate dimeglumine) at doses of 0.05 and 0.15 mmol/kg and at 0.1 and 0.2 mmol/kg. RESULTS: Compared with predose images alone, efficacy was demonstrated in each of the gadobenate dimeglumine and gadodiamide groups (single and cumulative doses) as indicated by the level of diagnostic information, number of lesions detected, and contrast-to-noise ratio measurements. The level of diagnostic information from gadobenate dimeglumine at 0.1 mmol/kg was equivalent to that with gadodiamide at the same dose. One of the two blinded reviewers found equivalence between the gadobenate dimeglumine 0.05 mmol/kg dose and gadodiamide at 0.1 mmol/kg. Both reviewers found the level of diagnostic information to be equivalent after the second dose of contrast for all three dosing regimens. The cumulative doses of gadobenate dimeglumine were well tolerated and as safe as gadodiamide. CONCLUSIONS: Gadobenate dimeglumine is comparable to gadodiamide in terms of safety and efficacy for imaging of CNS lesions, with a possible advantage in imaging applications owing to enhanced T1 relaxivity.

Brain Neoplasms↗
PubMed2000

Temporal lobe injury in temporal bone fractures.

OBJECTIVE: To determine the incidence of intracranial injury, specifically in the temporal lobe, in patients with longitudinal fractures of the temporal bone. DESIGN: Prospective inception cohort. SETTING: University of Maryland Division of Otolaryngology-Head and Neck Surgery and the Maryland Shock Trauma Center, Baltimore. PATIENTS: Twenty-seven consecutive patients with unilateral or bilateral temporal bone fractures. MAIN OUTCOME MEASURES: Evaluation of temporal bone and intracranial trauma using computed tomography (CT) and magnetic resonance imaging (MRI). RESULTS: Of the 27 patients enrolled in the study, 12 had the complete battery of MRI, CT, and physical and audiological examinations. In all 12 patients, MRI demonstrated adjacent middle cranial fossa meningeal enhancement. Results of non-contrast-enhanced CT and MRI demonstrated ipsilateral temporal lobe contusions in 6 of the 13 fractures for an overall incidence of 46%. In addition, MRI demonstrated 4 cerebral contusions not seen in the results of non-contrast-enhanced CT. CONCLUSIONS: While high-resolution CT remains the criterion standard for evaluation of temporal bone fractures, MRI revealed a higher incidence of related temporal lobe injuries. Magnetic resonance imaging data may be valuable in preoperative evaluation of patients who require surgical intervention through a middle cranial fossa approach to document pre-existing injury and potential morbidity before retraction of the middle cranial fossa dura mater and temporal lobe.

Adolescent↗
PubMed1999

Surgically confirmed incorporation of a chronically retained neurointerventional microcatheter in the carotid artery.

A woman reported painful thrombosis of the superficial femoral artery 16 months after a transfemoral microcatheter was glued into a cerebral arteriovenous malformation and transected at the groin. When the catheter was removed, a portion was found to be incorporated into the wall of the carotid artery. This case demonstrates that portions of a retained microcatheter may be incorporated into the arterial wall while other portions may remain mobile and cause late peripheral arterial symptoms.

Adult↗
PubMed1998

Intra-arterial papaverine treatment for cerebral vasospasm: our experience and review of the literature.

We described the techniques and efficacy of intra-arterial papaverine hydrochloride infusion (IA-PAP) for symptomatic vasospasm due to aneurysmal subarachnoid hemorrhage based on our experience and review of the literature. Angiographic improvement occurred almost always, but only 50% of patients who presented with acute symptoms showed remarkable clinical improvement after the first, second, or third IA-PAP. Recurrent vasospasm after IA-PAP frequently occurred and this seems to be an apparent source of controversy regarding its efficacy. Review of the literature indicates that IA-PAP may be most effective in combination with percutaneous transluminal angioplasty. Further controlled studies should be conducted regarding papaverine's true efficacy including most effective papaverine concentration and rate of infusion, maximum total dose, site of infusion, timing of treatment, and selection of patients.

Cerebral Angiography↗
PubMed1998

Systemic sarcoidosis with bilateral orbital involvement: MR findings.

A 43-year-old woman with diplopia had a disconjugate gaze on physical examination. MR images revealed enlarged, abnormally enhancing extraocular muscles and lacrimal glands bilaterally. Biopsy results were consistent with sarcoidosis. Chest radiographs and CT scans were normal. Clinical and MR findings improved after appropriate medical therapy.

Adult↗
PubMed1998

Superior blowout fracture of the orbit: the blowup fracture.

We describe a patient who sustained a blowout fracture of the superior orbital roof without an orbital rim fracture. The initial CT study (obtained with 10-mm-thick sections) did not show herniation of the intraorbital fat into the anterior cranial fossa; however, thin (3-mm-thick) direct orbital sections showed a fracture of the midportion of the superomedial orbital roof with displacement of the fracture fragment into the anterior cranial fossa.

Adipose Tissue↗
PubMed1998

Performance characteristics of microcatheter systems in a standardized tortuous pathway.

BACKGROUND AND PURPOSE: Published reports of controlled experiments designed to evaluate the performance of over-the-wire microcatheter systems are rare and have often been based on subjective impressions from small clinical series. This investigation was designed to compare the load forces required to propel state-of-the-art, hydrophilically coated microcatheters from each of four manufacturers through a standardized tortuous pathway constructed of polytetrafluoroethylene tubing. METHODS: Currently available hydrophilically coated microcatheters were provided by four manufacturers. A 20-cm long, three-dimensional pathway simulating the intracranial carotid circulation was constructed of 0.065-in. (inner diameter) polytetrafluoroethylene tubing and immersed in a water bath at 37 degrees C. Testing was performed using an Instron tabletop load frame fitted with a 2-lb load cell. Durability and load force tests were conducted using a 0.014-in. stainless steel noncoated guidewire, with the wire tip protruding 1 cm beyond the catheter tip. At least four samples of microcatheters from each manufacturer were tested. RESULTS: Extensive trackability testing of the guidewire alone established reproducible performance with maximum load forces of less than 8 g. Maximum gram forces for the four reinforced microcatheters were not greatly different, measuring between 9 and 14 g. Excessive buckling of the only nonreinforced catheter was initially overcome early in the pathway in a staccato, stepwise fashion. After reaching a critical load, however, the catheter and guidewire prolapsed. CONCLUSION: All reinforced microcatheters tested established good and reproducible performance in our model. Reinforced microcatheters provided superior trackability over the one nonreinforced device tested.

Angioplasty, Balloon↗
PubMed1997

Repeat intra-arterial papaverine for recurrent cerebral vasospasm after subarachnoid haemorrhage.

We assessed the prevalence of recurrent vasospasm following failure of intra-arterial papaverine and the efficacy of repeat intra-arterial infusions of papaverine for control of recurrent vasospasm. Of 24 patients treated with intra-arterial papaverine for vasospasm following aneurysm surgery, 12 did not improve clinically after the initial treatment; 9 received second or third infusions on consecutive days; 6 received only a second infusion; and 3 received a third. Superselective infusion into the intracranial arteries was performed in all nine cases. Despite angiographic improvement after the initial or second infusions, all nine patients showed varying degrees of recurrent vasospasm at the time of the second or third treatment. Within 24 h of a second infusion, three of the six patients had significant clinical improvement, and one of these showed marked improvement soon after a third infusion. Our preliminary results suggest that repeat papaverine infusion may be a way of controlling recurrent or recalcitrant vasospasm.

Adult↗
PubMed1996

Radiosurgery for cerebral arteriovenous malformations: assessment of early phase magnetic resonance imaging and significance of gadolinium-DTPA enhancement.

PURPOSE: To evaluate the initial changes within the nidus of arteriovenous malformations (AVMs) and to assess the reaction to the brain tissue surrounding AVMs after radiosurgery by serial magnetic resonance (MR) imaging. METHODS AND MATERIALS: Twenty-one patients, treated using 60Co gamma knife unit with cerebral AVMs, were retrospectively evaluated. Forty-seven follow-up MR images of the 21 patients were performed including 10 patients with two or more serial gadolinium enhanced studies (Gd-MR). Two or more sequential MR angiographies (MRA) were obtained in 13 patients. Three-dimensional (3D) time-of-flight MRA and two-dimensional (2D) phase contrast MRA were used in 13 patients for evaluating the flow changes of AVMs. The follow-up period after radiosurgery ranged from 3 to 30 months (average 10.8 months) and the interval time of MRI ranged from 34 days to 13 months (average 4.9 months). RESULTS: Reduction of nidus size was observed in 14 of 21 patients (67%) between 4 to 13 months on spin echo (SE) images. Complete obliteration was observed on SE images in 4 of these 14 patients; three were confirmed by conventional angiography. New hyperintense areas surrounding the nidus on T2s-weighted images (T2WI) developed in 9 of the 14 patients who showed nidus reduction between 5 to 17 months after radiosurgery; in three patients, size of the hyperintense area started to decrease between 6 to 7 months after its appearance. Probable radiation necrosis of pons developed in one patient 26 months after radiosurgery. The irradiated area within the AVM nidus was significantly enhanced in 8 of the 10 patients who underwent Gd-MR. The degrees of enhancement within the nidus increased with time in 7 of the 10 patients. Overall, total enhancement of irradiated areas was observed in four of the 10 patients; in three of the four, the enhancement decreased in size and degree, indicating nidus reduction. In three patients who had a partial volume irradiation within the nidus, the enhancing areas corresponded with the exact portions of irradiated volume. The nidus reduction was observed in 7 of the 13 patients on MRA during 5 to 13 months after radiosurgery. MRA was more useful compared to SE images in four of the seven patients in evaluating the size change of AVM nidus, feeding arteries, and draining veins. CONCLUSION: Magnetic resonance imaging and MRA were useful in assessing the progress of nidus reduction. T2-weighted imaging was sensitive to radiation-induced reaction in and around the AVM nidus. The enhancement within the AVM nidus on Gd-MR may represent the initial sign of nidus reduction and demonstrates the exact location of irradiation in the nidus. The changes of the enhancement pattern are presumed to represent the processes of nidus reduction and irradiated reaction within the AVM nidus.

Adolescent↗
PubMed1995

Radiologic appearance of the dysembryoplastic neuroepithelial tumor.

PURPOSE: To evaluate the computed tomographic (CT) and magnetic resonance (MR) imaging features of dysembryoplastic neuroepithelial tumor (DNT). MATERIALS AND METHODS: Six CT studies (four with contrast material enhancement) and 10 MR imaging studies (seven with gadolinium enhancement) obtained in 10 patients with a history of seizures and pathologically proved DNT were retrospectively reviewed. RESULTS: All tumors were intracortical or subcortical. CT showed a low-attenuation mass in all cases except one of mixed isoattenuation and low attenuation. The DNT had decreased signal intensity on T1-weighted MR images and well-demarcated increased signal intensity on T2-weighted images without peritumoral edema. Prominent MR imaging features were a gyriform configuration on T1- or T2-weighted images in 10 patients (100%), well-demarcated lobular tumor margins on T2-weighted images in eight (80%), and a high rate of bone remodeling of the adjacent calvaria on MR (60% [n = 6]) and CT (67% [n = 4]) images. CONCLUSION: Diagnosis of DNT with imaging modalities alone may be difficult, but these radiologic features may aid in differentiating DNT from other gliomas.

Adolescent↗
PubMed1995

Posterior fossa glioblastoma multiforme: MR findings.

PURPOSE: To characterize the MR findings of glioblastoma multiforme in the posterior fossa. METHODS: MR studies of nine patients with surgically proved posterior fossa glioblastoma multiforme were retrospectively evaluated. MR characteristics studied included tumor location, signal intensity, enhancement pattern, and presence of intratumoral hemorrhage, as well as presence of secondary hydrocephalus or metastatic spread. RESULTS: The tumors were located in the median portion of the cerebellum or brain stem in eight cases. Six extended into the fourth ventricle. Hydrocephalus was seen in four cases. Six cases demonstrated decreased T1- and increased T2-weighted signal intensities. Three cases demonstrated mixed signal intensities suggesting intratumoral hemorrhage. All of the eight patients who received contrast showed moderate to marked heterogeneous ringlike enhancement suggesting intratumoral necrosis. Multicentric/multifocal lesions or extraaxial metastases were identified in three of the nine cases, and there was extracranial extension into the cervical region in one case. CONCLUSION: Glioblastoma multiforme is a rare tumor in the posterior fossa. Differentiating it from metastatic tumor or malignant astrocytoma was difficult. However, combination of heterogeneous and ringlike enhancement, midline location, poorly defined margin, tumoral hemorrhage, concomitant multicentric/multifocal lesions, and extraaxial or extracranial metastasis may be clues for the prospective diagnosis of glioblastoma multiforme.

Adult↗
PubMed1995

Intraarterial papaverine infusion for cerebral vasospasm after subarachnoid hemorrhage.

PURPOSE: To evaluate the techniques and efficacy of intracranial intraarterial papaverine infusion for symptomatic vasospasm after subarachnoid hemorrhage caused by aneurysm rupture. METHODS: Papaverine was infused on 19 occasions in 14 patients, 6 hours to 2 days after spasm became apparent clinically. Sixty vascular territories were treated. Infusion was made into the supraclinoid internal carotid artery 20 times, cavernous internal carotid artery once, selective A1 anterior cerebral artery 8 times, M1 middle cerebral artery 7 times, and basilar artery 3 times. Papaverine doses ranged from 150 to 600 mg and exceeded 400 mg on 8 occasions. RESULTS: Angiographic improvement occurred in 18 (95%) of the 19 treatment sessions: results were excellent in 3 sessions, moderate in 8, and mild in 7. The best angiographic results often were obtained with superselective infusion, although angiographic results did not always correlate with clinical response. Seven (50%) of the 14 treated patients showed dramatic acute clinical improvement within 24 hours of papaverine therapy, and there was no clinical evidence of recurrent vasospasm in these patients. Recurrence of angiographic vasoconstriction was demonstrated in three patients; one showed marked clinical improvement after a second treatment. There were no episodes of systemic hypotension in any of the cases. Monocular blindness developed in one patient because of papaverine infusion near the ophthalmic artery. CONCLUSIONS: Papaverine was effective in dilating narrowed arteries in most patients with symptomatic vasospasm caused by subarachnoid hemorrhage. This series showed encouraging clinical results with no recurrence of neurologic deterioration in those patients who responded well to papaverine. Superselective infusion appears to be indicated in some cases for adequate papaverine delivery.

Adult↗
PubMed1994

Extradural causes of myelopathy.

Myelopathy, the rapid or insidious onset of motor and sensory abnormalities referable to the spinal cord, occurs as a result of a variety of causes that may be classified on the basis of their location of origin (intramedullary, intradural-extramedullary, and extradural). The first goal of imaging is to appropriately assign the observed abnormality to its location of origin and, therefore, into the correct diagnostic list. This article focuses on the plain film, computed tomography, and magnetic resonance demonstration of extradural causes of myelopathy.

Bacterial Infections↗