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Biomedical subjects

G B Bradac

Publications and source records attributed to G B Bradac.

At least 19 recordsLinked to original sources
PubMed2007

Periprocedural morbidity and mortality by endovascular treatment of cerebral aneurysms with GDC: a retrospective 12-year experience of a single center.

Despite increasing experience and improved material, endovascular treatment of cerebral aneurysms still has risks linked to the technique itself and to the specificity of the pathology treated. The purpose of this report is to examine procedural technical and clinical negative events, even minimal ones, occurring in this type of treatment. We considered 557 procedures carried out from January 1994 to December 2005 in 533 patients harboring 550 aneurysms. Of the patients, 448 presented with SAH and 85 with unruptured aneurysms. All procedures were performed under general anesthesia. The GDC-10 system was routinely used. Additional devices like the balloon remodeling technique, Trispan and stents were also occasionally used. Every procedural complication occurring during or soon after treatment was registered. Endovascular treatment was completed in 539 out of 557 procedures. There were 18 failures (3.3%). Occlusion of the aneurysm was judged complete in 343 (64%), near complete in 184 (34%) and incomplete in 12 (2%). Procedural complications occurred in 72 (13%) of the cases. The most frequent negative events were thromboembolisms (6.6%) and ruptures (3.9%). Other types (coil migration, transient occlusions of the parent vessel, dissections and early rebleeding) were rarer (2.5%). In the majority of cases there were no clinical consequences. Procedural morbidity and mortality were 1.1 and 1.8%, respectively. Considering the 449 procedures performed in ruptured and the 90 in the unruptured aneurysms separately, morbidity and mortality were 1.1 and 2.2% in the former group and 1.1 and 0% in the latter. Many factors influence the risk of complications. Being progressively aware of this and with increasing experience, the frequency can be limited. Negative events linked to the procedure have more significant serious clinical consequences in patients admitted in a critical clinical condition after SAH, because of the already present changes involving the brain parenchyma and cerebral circulation.

Adult↗
PubMed2006

The effect of gender on planning: An fMRI study using the Tower of London task.

Since the introduction of brain mapping, evidences of functional gender differences have been corroborating previous behavioral and neuropsychological results showing a sex-specific brain organization. We investigated gender differences in brain activation during the performance of the Tower of London (TOL) task which is a standardized test to assess executive functions. Eighteen healthy subjects (9 females and 9 males) underwent fMRI scanning while solving a series of TOL problems with different levels of difficulty. Data were analyzed by modeling both genders and difficulty task load. Task-elicited brain activations comprised a bilateral fronto-parietal network, common to both genders; within this network, females activated more than males in dorsolateral prefrontal cortex (DLPFC) and right parietal cortex, whereas males showed higher activity in precuneus. A prominent parietal activity was found at low level of difficulty while, with heavier task demand, several frontal regions and subcortical structures were recruited. Our results suggest peculiar gender strategies, with males relying more on visuospatial abilities and females on executive processing.

Adult↗
PubMed2006

Functional MR study of a motor task and the tower of London task at 1.0 T.

INTRODUCTION: The use of functional magnetic resonance imaging (fMRI) for clinical applications and basic neuroscience is constantly increasing. The discussion about minimum performance requirement for a correct implementation of fMRI is still open, and one of the critical points is the magnetic field strength. We tested the feasibility of fMRI at 1.0 T during motor and cognitive tasks. METHODS: Fourteen healthy subjects were scanned during a motor task and 12 while performing the Tower of London task. In the activated areas, the percentage signal change due to BOLD (blood oxygenation level dependent) contrast was analysed. To check basic image quality of the acquisition system we measured quality indices in a temporal series of images of a phantom. RESULTS: Motor and cognitive brain activations matched previous results obtained at higher field strengths. The mean percentage change over subjects in the motor task was in the range 1.3-2.6% for the primary motor area and 0.8-6.7% for the cerebellum. In the cognitive task, the mean percentage change over subjects was 0.7-1.2% for a frontal area and 0.6-2.8% for a parietal area. The percentage noise of the phantom temporal series was less than 0.4%. Percentage changes and signal to noise ratio, although lower than that obtained with high-field systems, allowed activation maps to be obtained in all subjects. CONCLUSION: Our results replicate previous fMRI results demonstrating reproducible motor-related brain activations and extend the field to a complex cognitive task, thus providing evidence of the safety for routine clinical use of 1-T equipment.

Adult↗
PubMed2005

Endovascular treatment of cerebral aneurysms in elderly patients.

We report our experience in the endovascular treatment with detachable platinum coils of ruptured or symptomatic unruptured cerebral aneurysms in 61 patients aged 70-82 years. Complete occlusion was achieved in 38, subtotal in 17 and partial in one. The treatment failed in five patients. Clinical follow-up was performed in all patients for 8 months to 8 years. No bleeding occurred during the follow-up period. Outcome was favourable in 63% of the patients. When we compared the outcome of elderly patients with those of younger age endovascularly treated in the same period of time, we found a significantly higher frequency of poorer outcome in the elderly group (chi(2) = 9.084; P = 0.011). The frequency of favourable outcome in the elderly was significantly lower than in the younger group for H-H IV-V (chi(2) = 9.299; P = 0.010). The most important factor influencing the outcome was not age itself, but primary clinical condition on admission. The therapy of symptomatic aneurysms in elderly patients should not be purely conservative--a direct approach of the aneurysm should be considered. Endovascular treatment whenever possible seems to be a good alternative to surgery.

Age Factors↗
PubMed2004

Endovascular treatment of the posterior inferior cerebellar artery aneurysms.

Aneurysms may arise at various locations along the course of the posterior inferior cerebellar artery. Brainstem and cranial nerves manipulation make the surgical approach to proximal aneurysms difficult, while the occlusion of the parent vessel is sometimes unavoidable in peripheral aneurysms. Endovascular treatment can be a good alternative, but also with this approach the location of the aneurysm is critical. If occlusion of the parent vessel is planned, anatomical variations and vascular territories of the brainstem should be considered. We report our experience with 18 consecutive aneurysms (12 proximal, 6 peripheral) treated by coils. Complete occlusion was achieved in 14 patients and subtotal in 4. In three patients the parent vessel had to be sacrificed. During treatment two perforations occurred; aneurysms were completely occluded without clinical consequences. Two small asymptomatic cerebellar infarctions were seen on postoperative computed tomography. Clinical outcome was good in 16 patients.

Adult↗
PubMed2003

Acute endovascular treatment of ruptured aneurysms in poor-grade patients.

We reviewed the 6-month outcome of 45 consecutive patients in poor grade treated acutely by coiling after subarachnoid haemorrhage (SAH). About half had a favourable outcome, a promising result in accordance with some surgical and endovascular reports proposing early aggressive treatment of an aneurysm causing SAH. The poor clinical grade, due to parenchyma damage from the SAH, remains the main prognostic factor, rebleeding from the untreated aneurysm being only one cause of poor outcome. It is therefore difficult to isolate the impact of any treatment of the aneurysm on outcome, and unavoidable selection bias may strongly influence favourable results. Nevertheless, available evidence and the limited invasiveness suggest that acute endovascular treatment is reasonable in these patients.

Acute Disease↗
PubMed2003

Progressive multifocal leukoencephalopathy: diffusion-weighted imaging and pathological correlations.

We examined MRI of two patients with progressive multifocal leukoencephalopathy (PML), including diffusion-weighted imaging (DWI), with calculation of apparent diffusion coefficients (ADC). The pathology findings of one patient were compared with those of MRI. The lesions had different ADC and DWI appearances, depending on the stage of the disease. Newer lesions and the advancing edge of large lesions had normal-to-low ADC and gave high signal on DWI. Older lesions and the centre of large lesions had increased ADC and gave low signal. High signal on DWI and low ADC mark the regions of active infection and cell swelling, distinguishing them from areas of reparative gliosis.

Adult↗
PubMed2003

Extensive cortical damage in a case of Creutzfeldt-Jacob disease: clinicoradiological correlations.

MRI demonstrated extensive cortical involvement in a patient with pathologically proven Creutzfeldt-Jacob disease. The whole brain was atrophic; some of the supratentorial cortex, putamen and caudate nucleus gave high signal on T2-weighted images; the changes were more extensive on diffusion-weighted images (DWI). Comparison of the history, and the sites of atrophy and signal change suggested that the latter predominates in regions with long-lasting damage and prevalent gliosis, while high signal on DWI indicate current neuronal loss. This case widens the range of MRI findings in patients with Creutzfeldt-Jacob disease, and suggests that some information about the progression of the disease can be extracted from single MRI study.

Brain↗
PubMed2001

Diffusion-weighted images of intracranial cyst-like lesions.

Magnetic resonance sequences may be designed to evaluate the diffusion movements of the protons (diffusion-weighted images, DWI). In these images, a bright signal identifies a region where the diffusion along a spatial axis is restricted. The contents of a cystic lesion frequently have the signal intensities of a generic homogeneous hyperproteinic fluid (hypointensity in T1-, hyperintensity in T2-weighted images). DWI may give further information about the microscopic organisation of these fluids: a hyperintense signal indicates the presence of a restricted diffusion, due to some kind of microscopic organisation, at the cellular or macromolecular level. This may provide additional information useful for clinical purposes. We obtained DWI in 24 consecutive patients with intracranial cystic lesions, (19 intra-axial: five abscesses, five gliomas, six metastases, two demyelinating lesions, one neurocysticercosis; five extraaxial: two arachnoid cysts, two epidermoid cysts, one cholesteatoma). We found a strongly hyperintense signal, indicating restricted diffusion, in brain abscesses, epidermoid cysts and cholesteatoma; all the remaining lesions were hypointense or mildly hyperintense. We found these data useful in critical diagnoses, such as in differentiating abscesses from tumours, and in identifying elusive tumours such as epidermoid cysts.

Adult↗
PubMed2001

Diffusion-weighted MR in reversible wernicke encephalopathy.

Diffusion-weighted images (DWI) of a patient with Wernicke encephalopathy were obtained during routine MR examination. Mammillary bodies were hyperintense on T2-weighted and enhanced on T1-weighted images; on DWI, a mild hyperintensity was noticed. Calculation of the apparent diffusion coefficient (ADC) demonstrated an increased diffusion on the affected regions; the hyperintensity on DWI was probably due to a "T2-shine-through" effect. These findings are consistent with the presence of extracellular oedema, without significant neuronal damage. The patient recovered promptly after thiamine administration, and MR alterations disappeared. The favourable evolution indicates that no relevant neuronal death occurred. This is consistent with DWI findings. DWI are more sensitive than ordinary T1- and T2-weighted images to neuronal irreversible damage, and may differentiate between neuronal necrosis and extracellular oedema in various brain pathologies. The demonstration of a limited neuronal damage may represent a favourable prognostic factor in patients with WE.

Adult↗
PubMed2001

Primitive cerebral melanoma: case report and review of the literature.

BACKGROUND: Central nervous system primary malignant melanoma accounts for approximately 1% of all the cases of melanoma; reports in the literature are relatively rare. CASE DESCRIPTION: A 74-year-old man was hospitalized because of an episode of aphasia. The neuroradiologic examinations demonstrated a round homogeneous lesion extending near the left sylvian fissure. He had no extracranial abnormalities. The patient underwent a neurosurgical procedure and the tumor was macroscopically totally excised. Pathological examination of the surgical specimen revealed a histological appearance similar to that of melanoma. A diagnosis of primary CNS melanoma was made after careful dermatologic and ophthalmologic examination, which ruled out presence of cutaneous or choroidal melanoma. The patient did not receive any further treatment and he is free of disease 2 years after diagnosis. CONCLUSIONS: We report a case of primary cerebral melanoma of the left temporal lobe; clinical, neuroradiological, and histological findings are discussed with review of the literature. Primary melanoma of the CNS may present either with localized intra/extra-axial mass lesions or with meningeal spread, which carries a worse prognosis. The prognosis of cerebral primitive melanoma is variable, although it is common opinion that primitive cerebral melanoma has a better prognosis than cutaneous melanoma, with two cases in the literature surviving 9 and 12 years.

Aphasia↗
PubMed1999

Transforming growth factor beta1 (TGFbeta1) mRNA level correlates with magnetic resonance imaging disease activity in multiple sclerosis patients.

Eight relapsing-remitting multiple sclerosis (MS) patients were tested for the level of transforming growth factor beta1 (TGFbeta1) mRNA in peripheral blood mononuclear cells every 15 days for 6 months. Disease activity was evaluated every 4 weeks by magnetic resonance imaging (MRI) and neurological examination. An inverse correlation was found between the level of TGFbeta1 mRNA and MRI disease activity. The level of TGFbeta1 mRNA predicted the presence of disease activity in the scans performed 2-4 weeks later with high sensitivity (88%) and specificity (87.5%) suggesting that TGFbeta1 mRNA quantification could be an indicator of disease activity in MS.

Adult↗
PubMed1999

Brain lesions due to cerebral venous thrombosis do not correlate with sinus involvement.

Cerebral venous thrombosis may be well tolerated or lead to a brain lesion; availability of collateral venous pathways may explain the great variability of the lesions. This collateral circulation involves mainly medullary and cortical veins. These are difficult to assess neuroradiologically, particularly if thrombosed. Cerebral venous thrombosis is diagnosed usually based on thrombosis of dural sinuses and of the deep venous system. We tried to correlate the site and extent of dural sinus thrombosis with the location and the size of brain lesions in 26 consecutive patients with cerebral venous thrombosis, to investigate whether a simple causal relationship exists. No significant correlation between the extent and site of thrombosis in dural sinuses and the extent and location of brain lesions was found. In some cases a clear relationship between thrombosis of cortical and medullary veins and the lesions was evident. These data suggest that sinus thrombosis alone may be well tolerated in many cases, while involvement of cortical and medullary veins leads to a worse clinical situation.

Adolescent↗
PubMed1998

PCV chemotherapy for recurrent oligodendrogliomas and oligoastrocytomas.

OBJECTIVE: The role of chemotherapy in the treatment of low-grade oligodendrogliomas and oligoastrocytomas is still unclear. A Phase II study was conducted to determine the benefits and toxicity of the procarbazine, lomustine, and vincristine (PCV) regimen in patients with low-grade oligodendrogliomas and oligoastrocytomas recurrent after surgery alone or surgery with radiotherapy. METHODS: Patients with both enhancing and nonenhancing tumors were treated with up to six cycles of standard PCV, and response was evaluated by conventional criteria based on computed tomography or magnetic resonance imaging. RESULTS: Sixteen of 26 patients (62%) responded to PCV: 3 (12%) experienced complete response, 13 (50%) experienced partial response, 8 (31%) had stable disease, and 2 (8%) had progressive disease. All symptomatic patients who responded and three with stable disease improved in seizure frequency, lateralizing signs, and symptoms of intracranial hypertension. The response rate for patients with enhancing lesions revealed by computed tomography or magnetic resonance imaging (74%) was significantly higher than that of patients with nonenhancing lesions (29%) (P < 0.05). Both oligodendrogliomas and oligoastrocytomas responded to PCV, with complete responses occurring in association with pure tumors only. The median time to tumor progression of all 26 patients was 24 months and was significantly longer for those with oligodendrogliomas compared with those with oligoastrocytomas (32 versus 12 mo) (P < 0.001). Chemotherapy was well tolerated, with mild hematological toxicity and rare skin rashes being the most frequent sequelae. CONCLUSION: These results suggest that chemotherapy with PCV is effective in the treatment of recurrent low-grade oligodendrogliomas and oligoastrocytomas.

Adult↗
PubMed1998

[Therapeutic decisions and grading of subarachnoid hemorrhage].

Early admission and medical treatment can improve prognosis in patients with subarachnoid hemorrhage (SAH). In our Centre in 10 years, 595 patients with SAH have been treated: 422 were admitted within 24 hours (71%) and 498 (84%) within 72 hours. 374 underwent surgical treatment: 283 within 48 hours and 91 underwent late surgery. Thirty-three patients underwent emergency surgery for intracranial hematomas, with a mortality rate of 30%. One hundred eighty-one patients in Hunt-Hess grade I-II underwent early surgery. Mortality rate was 7%. Mortality rate for rebleeding, when surgery was delayed was more than 10%. Patients in Hunt-Hess grade III underwent early surgery in the majority of cases (68 out of 111). Only in 52% of cases surgical result was good. Thirty-four out of 108 in grade IV-V underwent early surgery, with a mortality rate of 45%. The analysis of general results shows that early surgery improves prognosis in Hunt-Hess grade III patients. Also patients in Hunt-Hess grade III-IV-V can take advantage of early surgery. Old age, arterial hypertension and angiographical vasospasm do not worsen prognosis even in patients operated on early. Endovascular treatment even in acute phase has improved results especially in cases of certain aneurysms types such as posterior circulation aneurysms.

Adult↗