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1.
AJNR Am J Neuroradiol ; 34(5): 1016-21, S1, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23306013

RESUMO

Hemolytic uremic syndrome is a multisystem disorder that is caused by infection with Shiga-toxin-producing Escherichia coli. HUS affects mainly children and is rare among adults. This retrospective case series analyzes clinical signs and MR imaging findings of 11 adult patients with HUS associated nervous system involvement during the epidemic EHEC outbreak in northern Europe with its epicenter in Hamburg in May 2011. The most prevalent imaging finding was symmetric pointy vasogenic edema of the brain stem in the acute and subacute phases of the disease (n = 5). One patient exhibited additional symmetric mesiotemporal signal changes mimicking limbic encephalitis. Two patients developed subcortical patchy lesions, and 4 subjects did not present with any signal changes. Remarkably, territorial ischemia, signs of hemorrhage, or blood-brain barrier disruption have not been detected. While brain stem lesions were transient and normalized with clinical recovery, supratentorial lesions did not resolve completely at 2-month follow-up examination.


Assuntos
Edema Encefálico/patologia , Encéfalo/patologia , Síndrome Hemolítico-Urêmica/patologia , Imageamento por Ressonância Magnética , Adulto , Edema Encefálico/epidemiologia , Surtos de Doenças/estatística & dados numéricos , Feminino , Alemanha/epidemiologia , Síndrome Hemolítico-Urêmica/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência
2.
Neuroradiology ; 49(4): 317-26, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17200864

RESUMO

INTRODUCTION: Impaired cerebral vascular reserve (CVR) in patients with symptomatic internal carotid artery (ICA) occlusion is regarded as a possible indication for performing extra-/intracranial (EC/IC) bypass surgery. As perfusion MR imaging (MRI) can demonstrate cerebral haemodynamics at capillary level, our hypothesis was that perfusion MRI could be used in these patients for the evaluation of CVR following acetazolamide challenge in a similar way to single photon emission CT (SPECT) and might provide additional information. METHODS: Enrolled in the study were 12 patients (mean age 61.3 years; 11 male, 1 female) with symptomatic unilateral ICA occlusion proven by angiography. Both perfusion MRI and 99m-technetium-ethyl-cysteinate dimer ((99m)Tc-ECD) SPECT were performed before and after injection of acetazolamide (Diamox ,1000 mg i.v.). CVR parameters including regional cerebral blood flow (rCBF) and volume (rCBV), and mean transit times (MTT) were measured by perfusion MRI. RESULTS: The patients with impaired CVR proven by SPECT (n = 9) had a negative mean rCBF increment (-46.52%), negative rCBV increment (-13.5%) and delayed MTT (mean +2.98 s), respectively, on the occluded side (Student's t-test all P < 0.05). The patients with sufficient CVR (n = 3) had a mean rCBF increment of 1.2%, a decrement of rCBV of 10.46%, and a mean MTT shortening of 0.27 s following the acetazolamide injection. CONCLUSIONS: Perfusion MRI before and after acetazolamide administration compares favourably with (99m)Tc-ECD SPECT for the detection of impaired CVR. The impact that perfusion MRI studies (before and after acetazolamide administration) might have on the treatment decision in patients with ICA occlusion has yet to be determined by a prospective study.


Assuntos
Acetazolamida , Artéria Carótida Interna , Estenose das Carótidas/diagnóstico por imagem , Estenose das Carótidas/diagnóstico , Cisteína/análogos & derivados , Imageamento por Ressonância Magnética/métodos , Compostos de Organotecnécio , Compostos Radiofarmacêuticos , Tomografia Computadorizada de Emissão de Fóton Único , Idoso , Circulação Cerebrovascular , Distribuição de Qui-Quadrado , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
3.
Neuroradiol J ; 19(6): 705-10, 2007 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-24351295

RESUMO

The purpose of this study was to compare diffusion-weighted MR imaging with conventional MR sequences in patients with amyotrophic lateral sclerosis (ALS) and controls, and to assess the diagnostic value of diffusion-weighted imaging in the ALS patients. Twelve patients with ALS (ten men and two women, mean age 56 years) and 12 age-matched control subjects were studied with axial diffusion-weighted imaging and conventional MR imaging. Three adjacent slices of diffusion-weighted imaging were obtained at the level of the internal capsule. The diffusion-weighted imaging was performed with a b-value from 165-600 s/mm(2). Identical slices of diffusion-weighted images and conventional MR images were evaluated by a consensus reading. Diffusion-weighted images showed high signal intensity in the corticospinal tract at the level of the internal capsule in 11/12 patients with ALS (92%) and 5/12 control subjects (42%), whereas T2-weighted images (T2WI) revealed high signal intensity in the corticospinal tract in 11/12 patients with ALS (92%) and 8/12 control subjects (67%). The proton-weighted images (PDWI) disclosed the high signal corticospinal tract in 5/12 patients with ALS (42%), but not in any of the control subjects. Considering ALS patients versus control subjects, statistical analysis demonstrated that diffusion-weighted imaging (p=0.027, X(2) test) and proton-weighted imaging (p=0.037) were more specific than T2-weighted imaging. Diffusion-weighted imaging and proton-weighted imaging were more specific than T2-weighted imaging. The combination of diffusion-weighted imaging and T2WI/PDWI seems a promising tool in the diagnosis of amyotrophic lateral sclerosis.

4.
Nervenarzt ; 77(10): 1232-4, 2006 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-17024479

RESUMO

Thunderclap headache describes a rare headache syndrome characterized by abrupt-onset severe headache mimicking subarachnoidal bleeding, which has to be excluded by adequate diagnostic procedures such as digital subtraction angiography. The pathophysiology is still not clear but there are an increasing number of reports which describe some kind of vasospasm of the intracranial arteries during the headache episode. Here we describe a patient with a thunderclap headache and a mid-basilar narrowing due to a reversible vasospasm.


Assuntos
Transtornos da Cefaleia Primários/etiologia , Nimodipina/uso terapêutico , Vasodilatadores/uso terapêutico , Vasoespasmo Intracraniano/complicações , Insuficiência Vertebrobasilar/complicações , Adulto , Angiografia Digital , Angiografia Cerebral , Diagnóstico Diferencial , Transtornos da Cefaleia Primários/tratamento farmacológico , Humanos , Angiografia por Ressonância Magnética , Masculino , Recidiva , Hemorragia Subaracnóidea/diagnóstico , Vasoespasmo Intracraniano/diagnóstico , Vasoespasmo Intracraniano/tratamento farmacológico , Insuficiência Vertebrobasilar/diagnóstico , Insuficiência Vertebrobasilar/tratamento farmacológico
5.
AJNR Am J Neuroradiol ; 27(6): 1326-31, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16775291

RESUMO

BACKGROUND AND PURPOSE: When using detachable coils to treat intracranial aneurysms, thromboembolism is the most feared and frequently reported complication during or after endovascular therapy. The purpose of this study was to document the therapeutic effect of tirofiban on patency of the parent vessel, rate of rebleedings, and outcome of the patients in the setting of acute subarachnoidal hemorrhage. METHODS: A patient data base was retrospectively reviewed to identify patients in whom thrombus occurred during endovascular treatment of ruptured cerebral aneurysms within a 34-month period and who were treated with tirofiban. All patients underwent anticoagulation with heparin during endovascular treatment procedures. Sixteen patients (age range, 52.9 +/- 10.7 years; 10 women, 6 men) were identified with intraprocedural thrombus formation. The patency of the parent vessel was assessed in a retrospective analysis blinded to outcome. Eight patients received ventriculostomy and had a follow-up CT. RESULTS: Local nonocclusive thrombus at the coil surface was detected in 5 patients, in all of whom the thrombus was dissolved. In 10 patients, partial or total occlusion of the parent vessel occurred during the intervention; in 8 of these, the vessel was recanalized completely and in 2 drug administration was assisted by mechanical means. In 1 patient, however, the occlusion persisted. No periprocedural rebleedings of the ruptured aneurysm occurred; 3 of 8 ventriculostomies had clinically silent small local bleedings. CONCLUSION: The use of tirofiban in the setting of endovascular treatment of ruptured intracranial aneurysms to dissolve platelet aggregation seems relatively safe and effective.


Assuntos
Aneurisma Roto/cirurgia , Embolização Terapêutica/efeitos adversos , Fibrinolíticos/administração & dosagem , Aneurisma Intracraniano/cirurgia , Trombose Intracraniana/tratamento farmacológico , Complicações Intraoperatórias/tratamento farmacológico , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/antagonistas & inibidores , Tirosina/análogos & derivados , Adulto , Idoso , Aneurisma Roto/complicações , Aneurisma Roto/diagnóstico por imagem , Angiografia Digital , Angiografia Cerebral , Feminino , Humanos , Infusões Intravenosas , Aneurisma Intracraniano/diagnóstico por imagem , Trombose Intracraniana/diagnóstico por imagem , Trombose Intracraniana/etiologia , Masculino , Pessoa de Meia-Idade , Hemorragia Subaracnóidea/etiologia , Tirofibana , Tirosina/administração & dosagem
6.
AJNR Am J Neuroradiol ; 27(1): 107-13, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16418367

RESUMO

BACKGROUND AND PURPOSE: To investigate image quality and vascular delineation of multisection CT (MSCT) angiography of the cervicocranial vessels with sliding-thin-slab (STS) maximum intensity projections (MIP) and multiplanar reformations (MPR). MATERIALS AND METHODS: Ten patients examined with a standardized protocol on a 16-section MSCT were included in the study. The data were reformatted as MIP and MPR in 3 planes for each subject; both reformatting techniques were applied in an STS technique with an increment of 3 mm. Images were evaluated independently by 3 blinded readers grading image quality parameters and vascular delineation of supra-aortic arteries and veins. An extension of the Mantel-Haenzel row mean score test was used to compare the distribution of scores for vascular delineation and image quality between STS MIP and STS MPR. RESULTS: STS MIP reformations were significantly superior to STS MPR in the delineation of all extra- and intracranial arteries and arterial segments and in the delineation of the cavernous sinus and the internal cerebral veins (P < .05). No significant differences were found for the large venous vessels, the visual assessment of vascular contrast, or the impact of imaging artifacts. CONCLUSION: Because STS MIP reformations were preferred to or equal to STS MPR in all aspects, we recommend STS MIP as the primary reformatting technique in MSCT angiography of the cervicocranial vessels in addition to viewing the source images.


Assuntos
Angiografia/métodos , Processamento de Imagem Assistida por Computador , Pescoço/irrigação sanguínea , Tomografia Computadorizada por Raios X/métodos , Idoso , Angiografia Cerebral/métodos , Feminino , Humanos , Masculino
7.
Cytogenet Genome Res ; 108(1-3): 175-82, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15545727

RESUMO

We report on reciprocal painting between humans and two Cercopithecini species, Erythrocebus patas (patas monkey) and Cercopithecus neglectus (De Brazza's monkey). Both human and monkeys chromosome-specific probes were made by degenerate oligonucleotide primed PCR (DOP-PCR) from flow sorted chromosomes. Metaphases of both monkey species were first hybridized with human chromosome-specific probes and then human metaphases were hybridized with chromosome paints from each monkey species. The human paint probes detected 34 homologous segments on the C. neglectus karyotype, while the C. neglectus probes, including the Y, revealed 41 homologous segments on the human karyotype. The probes specific for human chromosomes detected 29 homologous segments in the E. patas karyotype, while the patas monkey probes painted 34 segments on the human karyotype. We tested various hypotheses of Cercopithecini phylogeny and taxonomy developed by morphologists, molecular biologists and cytogeneticists. Our hybridization data confirm that fissions (both Robertsonian and non-Robertsonian) are the main mechanism driving the evolutionary trend in Cercopithecini toward higher diploid numbers and strongly suggest an early phylogenetic bifurcation in Cercopithecini. One branch leads to Cercopithecus neglectus/Cercopithecus wolfi while the other line leads to Erythrocebus patas/Chlorocebus aethiops. Allenopithecus nigroviridis may have diverged prior to this major phylogenetic node.


Assuntos
Cercopithecinae/genética , Cercopithecus/genética , Coloração Cromossômica/métodos , Cromossomos Humanos/genética , Cromossomos de Mamíferos/genética , Erythrocebus patas/genética , Filogenia , Animais , Sondas de DNA/genética , Citometria de Fluxo/métodos , Humanos , Homologia de Sequência do Ácido Nucleico
8.
J Neuroradiol ; 31(3): 190-7, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15356444

RESUMO

PURPOSE: MR based first-pass method can be utilized to obtain hemodynamic information in the head and neck region. The purpose of this study was to estimate the regional relative blood volume (rBV) in head and neck tumors, which is useful for tumor staging and tumor biopsy. METHODS: Eighteen patients with head and neck tumors (17 squamous cell carcinomas, 1 hemangiopericytoma) were studied on a 1.5-T system. Conventional T1-weighted MR images and T2-weighted images and sequential T2*-weighted images were obtained. During repetitive image sequence acquisition, a bolus (0.2 mmol/kg) of gadopentetate dimeglumine was mechanically injected. Image processing of the dynamic raw data was performed on a pixel-by-pixel basis. RESULTS: Regional relative blood volume maps of the head and neck were successfully reconstructed in all (18/18) patients. The regional relative blood volume values within the tumor area of squamous cell carcinoma were 7.0 +/- 2.8, normalized on muscle, whereas the rBV of a single hemangiopericytoma was 11.6. The difference of rBV values of tumor and muscle was highly significant at statistical evaluation (p < 0.001). CONCLUSIONS: Relative blood volume imaging of head and neck tumors is valid using MR-based first-pass method. This method provides hemodynamic information which is not available from conventional MR imaging and is promising for further characterization of head and neck tumors


Assuntos
Volume Sanguíneo/fisiologia , Carcinoma de Células Escamosas/irrigação sanguínea , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Neoplasias Otorrinolaringológicas/irrigação sanguínea , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Carcinoma de Células Escamosas/patologia , Meios de Contraste/administração & dosagem , Meios de Contraste/farmacocinética , Diagnóstico Diferencial , Feminino , Gadolínio DTPA/farmacocinética , Hemangiopericitoma/irrigação sanguínea , Hemangiopericitoma/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Músculos do Pescoço/irrigação sanguínea , Músculos do Pescoço/patologia , Estadiamento de Neoplasias , Neoplasias Otorrinolaringológicas/patologia , Valores de Referência , Sensibilidade e Especificidade
9.
Eur Arch Otorhinolaryngol ; 260(10): 568-75, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12827382

RESUMO

At the present time, the partial and/or complete reconstruction of an auricle from autologous rib cartilage is one of most widely published techniques. In the field of tissue engineering, different techniques have been described to generate cartilage tissue using isolated chondrocytes. The basis of these tissue-engineering techniques is bioresorbable or non-bioresorbable biomaterials, which serve as a three-dimensional cell carrier. Tissue engineering of an auricle requires preformed bioresorbable biomaterials designed to fit the form of a patient's auricular defect. Three-dimensional imaging acquired from computed tomography scans or laser surface scanning has become an important tool in modern medicine. This study represents the preoperative procedures for the reconstruction of an auricle through tissue engineering in accordance with the clinical aspects. Hyaff 11, a hyaluronic acid derivative, was used as a three-dimensional cell carrier for isolated human nasoseptal chondrocytes. The chondrocytes were amplified in a conventional monolayer culture before the cells were seeded on a hyaluronic non-woven mesh and cultured in vitro for 4 weeks. The chondrogenic potential of human nasal chondrocytes in Hyaff 11 was investigated by confocal laser scanning microscopy, histology (toluidine blue) and immunohistochemistry (collagen type II). Computer-aided design (CAD) and manufacture of an auricle model with stereolithographical methods were used for the prefabrication of a bioresorbable three-dimensional cell carrier designed in the form of a patient's auricular defect. The cell carrier used was Hyaff 11, a fully benzyl-esterified hyaluronic acid derivative. Confocal laser scanning microscopy has shown good cell attachment, a homogenous distribution of amplified chondrocytes and a viability of more than 90%. After 4 weeks in vitro culture the human nasoseptal chondrocytes synthesized new cartilage with the expression of cartilage-specific collagen type II. In order to shape a patient's designed scaffold the auricle model was fitted exactly and symetrically to the contralateral side. Subsequently, the mirror image patient-specific model was used to prepare an identical scaffold model made of a fully benzyl-esterified hyaluronic acid derivative. The bioresorbable scaffold that was produced gave a satisfactory representation of auricle structure. Bioresorbable preformed biomaterials in the form of a patient's auricle defect represent an important prerequisite for the tissue engineering of autologous auricle grafts. Hyaff 11 seems to be a promising material for tissue engineering of cartilage transplants, and the application of this approach will improve conventional reconstructive surgery in the future.


Assuntos
Orelha Externa , Ácido Hialurônico/análogos & derivados , Desenho de Prótese/métodos , Engenharia Tecidual/métodos , Implantes Absorvíveis , Materiais Biocompatíveis , Células Cultivadas , Condrócitos/citologia , Desenho Assistido por Computador , Orelha Externa/anormalidades , Orelha Externa/lesões , Orelha Externa/cirurgia , Humanos , Imageamento Tridimensional , Masculino , Microscopia Confocal , Pessoa de Meia-Idade , Nariz , Tomografia Computadorizada por Raios X
10.
AJNR Am J Neuroradiol ; 22(7): 1268-74, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11498413

RESUMO

BACKGROUND AND PURPOSE: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an arteriopathic syndrome related to a genetic defect on chromosome 19. Characteristic changes in CADASIL can be observed onT2-weighted MR images in the subcortical white matter. The purpose of this study was to measure changes of regional cerebral blood volume (rCBV) with dynamic contrast-enhanced MR imaging and to correlate the changes to disability and cognitive performance. METHODS: We obtained rCBV measurements of 24 individuals with proven CADASIL on a 1.5-T MR imaging unit. A susceptibility-weighted MR imaging sequence was used for bolus tracking. Principles of the indicator dilution theory were applied to estimate values of absolute rCBV (mL/100 g). Disability was determined by using the Rankin scale, and overall cognitive performance was assessed by using the Mini-Mental State Examination. RESULTS: The mean rCBV in the subcortical white matter that was hyperintense on the T2-weighted images (2.7 +/- 0.8 mL/100 g) was significantly lower than the rCBV in the white matter that appeared normal on the T2-weighted images (4.4 +/- 1.3 mL/100 g) (P <.05). The mean rCBV in the gray matter was within the normal range (8.3 +/- 1.7 mL/100 g). Both cognitive impairment and disability negatively correlated with rCBV in the subcortical white matter that was hyperintense (P <.05) but not with rCBV in the normal appearing white matter. rCBV did not correlate with age. CONCLUSION: rCBV measured in the hyperintense subcortical white matter in individuals with CADASIL was decreased and inversely correlated with disability and cognitive impairment.


Assuntos
Doenças Arteriais Cerebrais/genética , Infarto Cerebral/genética , Aberrações Cromossômicas/genética , Demência Vascular/genética , Demência/genética , Avaliação da Deficiência , Genes Dominantes/genética , Adulto , Idoso , Volume Sanguíneo/fisiologia , Encéfalo/irrigação sanguínea , Doenças Arteriais Cerebrais/diagnóstico , Infarto Cerebral/diagnóstico , Transtornos Cromossômicos , Demência/diagnóstico , Demência Vascular/diagnóstico , Dominância Cerebral/fisiologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Entrevista Psiquiátrica Padronizada , Pessoa de Meia-Idade , Exame Neurológico , Fluxo Sanguíneo Regional/fisiologia , Síndrome
11.
AJR Am J Roentgenol ; 177(1): 179-84, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11418423

RESUMO

OBJECTIVE: We tested breath-held 1-mm multislice helical CT for obtaining both contiguous and high-resolution CT sections of the chest from a single set of raw data. SUBJECTS AND METHODS: Seventy patients with suspected focal and diffuse lung disease were allocated into two groups for comparison. The first group (n = 35) underwent multislice helical CT of the chest with 1-mm collimation and a pitch of 6. From the raw data, 5-mm contiguous and 1.25-mm high-resolution CT sections were reconstructed. The second group (n = 35) underwent conventional single-slice helical CT and high-resolution CT. High-resolution CT sections and 5-mm scans were rated for overall image quality, spatial resolution, subjective signal-to-noise ratio, diagnostic value, depiction of bronchi and parenchyma, and motion and streak artifacts. The 5-mm scans were also rated for contrast resolution and depiction of the heart and vessels. Radiation dose was calculated. RESULTS: We rated 5-mm multislice helical CT superior to 5-mm single-slice helical CT, having a significantly higher total score (p = 0.0001). No significant difference (p = 0.986) was found between multislice and single-slice high-resolution CT sections. Radiation dose was 5.55 mSv for multislice helical CT and 5.50 mSv for single-slice helical CT. CONCLUSION: Contiguous chest scans of superior quality and high-resolution CT sections of equal image quality compared with single-slice helical CT can be obtained using multislice helical CT. Therefore, a comprehensive diagnosis is feasible in patients with suspected focal and diffuse lung disease by obtaining a single scan.


Assuntos
Pneumopatias/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adulto , Feminino , Humanos , Pessoa de Meia-Idade
12.
Radiology ; 217(3): 693-700, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11110930

RESUMO

PURPOSE: To comprehensively assess thoracic anatomy and pulmonary microcirculation in pulmonary embolism by using computed tomographic (CT) angiography of the pulmonary arteries combined with functional CT imaging of blood flow. MATERIALS AND METHODS: Twenty-two patients suspected of having acute pulmonary embolism underwent contrast material-enhanced thin-section electron-beam CT angiography of the pulmonary arteries. In addition, in each patient, a dynamic multisection blood flow CT study was performed on a 7.6-cm lung volume with electrocardiographic gating. Pulmonary blood flow was calculated, and perfusion parameters were visualized on color-coded maps. The color-coded maps and CT angiograms were independently evaluated, segment by segment, by two readers for perfusion deficits and the presence of clots, respectively. The results were compared. RESULTS: Mean pulmonary blood flow was 0.63 mL/min/mL in the occluded segments versus 2.27 mL/min/mL in the nonoccluded segments (P: =.001). The sensitivity and specificity of perfusion maps for the presence of segmental pulmonary embolism compared with those of CT angiography were 75.4% and 82.3%, respectively, with positive and negative predictive values of 79.6% and 84.7%, respectively. The false-negative findings were caused mainly by partial occlusion of vessels. In eight patients, a substantial alternative or additional pathologic entity was diagnosed. CONCLUSION: By combining CT angiography and dynamic CT imaging, a comprehensive and noninvasive diagnosis of thoracic structure and function is feasible with a single modality.


Assuntos
Artéria Pulmonar/diagnóstico por imagem , Circulação Pulmonar , Embolia Pulmonar/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Doença Aguda , Adulto , Idoso , Angiografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Artéria Pulmonar/fisiopatologia , Embolia Pulmonar/fisiopatologia
13.
J Org Chem ; 65(20): 6534-9, 2000 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-11052098

RESUMO

Two new compounds, pycnanthuquinone A (1) and pycnanthuquinone B (2), were isolated from leaves and stems of the African plant, Pycnanthus angolensis (Welw.) Warb (Myristicaceae), by bioassay-guided fractionation of an ethanolic extract using a diabetic mouse model. Pycnanthuquinones A and B are the first representatives of a novel terpenoid-type quinone skeleton, and both compounds possess significant antihyperglycemic activity.


Assuntos
Ácidos Graxos Insaturados/isolamento & purificação , Hipoglicemiantes/isolamento & purificação , Naftoquinonas/isolamento & purificação , Plantas Medicinais/química , África , Animais , Glicemia/metabolismo , Peso Corporal/efeitos dos fármacos , Diabetes Mellitus/sangue , Diabetes Mellitus/genética , Ingestão de Alimentos/efeitos dos fármacos , Ácidos Graxos Insaturados/farmacologia , Hipoglicemiantes/farmacologia , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Naftoquinonas/farmacologia , Extratos Vegetais/química , Folhas de Planta/química , Caules de Planta/química
14.
AJNR Am J Neuroradiol ; 21(9): 1603-10, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11039338

RESUMO

BACKGROUND AND PURPOSE: Reconstruction of first-pass bolus information to derive regional cerebral blood volume (rCBV) maps is commonly performed in many centers; however, various protocols with different doses of paramagnetic contrast injections have been reported. We evaluated the dose dependency of rCBV maps in a brain tumor population by using three different doses of gadodiamide injection to evaluate their diagnostic accuracy in blinded reader sessions. METHODS: Eighty-three patients with intraaxial brain tumors (72 gliomas) were studied at three centers and randomized to receive a bolus injection of 0.1, 0.2, or 0.3 mmol/kg per body weight of gadodiamide. rCBV maps were generated from T2*-weighted gradient-echo echoplanar sequences at 1.5 T. Data processing was performed according to the indicator dilution theory. RESULTS: The mean contrast-to-noise ratio (CNR) was significantly different between gadodiamide doses of 0.1 and 0.2 mmol/kg (CNR = 8.7 and 15.7) and between 0.1 and 0.3 mmol/kg (CNR = 17.7). No significant difference was found between doses of 0.2 and 0.3 mmol/kg. Sensitivity for the differentiation of benign and malignant brain tumors was 80%, 95%, and 91%, and specificity was 45%, 54%, and 43% by blinded readings at 0.1, 0.2, and 0.3 mmol/ kg, respectively, as compared with histologic findings. Nonblinded readings had a sensitivity of 83%, 100%, and 90% and a specificity of 82%, 100%, and 73% at 0.1, 0.2, and 0.3 mmol/kg, respectively. CONCLUSION: A dose of 0.2 mmol/kg of gadodiamide is recommended for reconstruction of rCBV maps if data are acquired with the T2*-weighted protocol described.


Assuntos
Volume Sanguíneo , Neoplasias Encefálicas/fisiopatologia , Circulação Cerebrovascular , Meios de Contraste/administração & dosagem , Gadolínio DTPA/administração & dosagem , Imageamento por Ressonância Magnética , Neoplasias Encefálicas/diagnóstico , Método Duplo-Cego , Feminino , Humanos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade
15.
Eur Radiol ; 10(4): 629-35, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10795546

RESUMO

This contribution reviews the pathology and morphology of coronary calcifications. It summarizes the indications for investigation of the coronary arteries. The standard protocols for scan acquisition using electron beam and conventional computed tomography are described as well as various methods for evaluation such as the traditional Agatston scoring method and the newer three-dimensional scoring algorithms. Guidelines for interpreting scores are also reviewed. Major limitations of the reproducibility of the calcium score measurement are summarized. Future aspects of multirow-detector spiral computed tomography with retrospective electrocardiographic triggering for quantifying coronary calcium are discussed.


Assuntos
Calcinose/diagnóstico por imagem , Doença da Artéria Coronariana/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Calcinose/epidemiologia , Calcinose/patologia , Doença da Artéria Coronariana/epidemiologia , Doença da Artéria Coronariana/patologia , Doença das Coronárias/diagnóstico por imagem , Doença das Coronárias/epidemiologia , Doença das Coronárias/patologia , Previsões , Humanos , Prevalência , Prognóstico , Reprodutibilidade dos Testes , Tomografia Computadorizada por Raios X/métodos
16.
Eur Radiol ; 10(3): 443-9, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10756993

RESUMO

We describe the findings from various cross-sectional imaging modalities in patients with cardiac valve adherent masses. The techniques are discussed, and imaging findings are compared with the results of cardiac surgery. All three patients had neurological symptoms and/or cardiac murmurs. Transthoracic and/or transesophageal echocardiography revealed the cardiac mass in all three. For differentiation of thrombus and cardiac neoplasm magnetic resonance imaging (MRI) was also performed in all three patients and electron-beam computed tomography (EBCT) in two. Fast segmented cine gradient-echo MRI techniques provided mass depiction in all patients, while T1-weighted spin-echo imaging failed in mass detection in one patient. None of the patients showed evidence of valve regurgitation or stenosis in flow sensitive cine MRI. EBCT excluded mass calcifications in both patients and reliably demonstrated the valve attached lesions. Although echocardiography is the modality of choice in evaluating cardiac masses and especially valve attached masses, MRI and EBCT provide additional information about tissue characteristics and allows an excellent overview of the cardiac and paracardiac morphology. Fast segmented cine gradient-echo MRI is especially able to depict even small tumors attached to rapidly moving cardiac valves, and valve competence can be easily assessed within the same examination.


Assuntos
Ecocardiografia , Fibroma/diagnóstico , Neoplasias Cardíacas/diagnóstico , Linfangioma/diagnóstico , Imageamento por Ressonância Magnética , Mixoma/diagnóstico , Tomografia Computadorizada por Raios X , Adulto , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/patologia , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valva Mitral/diagnóstico por imagem , Valva Mitral/patologia
17.
Radiology ; 214(2): 433-9, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10671591

RESUMO

PURPOSE: To compare contrast agent-enhanced spiral and electron-beam computed tomography (CT) for the analysis of segmental and subsegmental pulmonary arteries. MATERIALS AND METHODS: CT angiography of the pulmonary arteries was performed in 56 patients to rule out pulmonary embolism. Electron-beam CT was performed in 28 patients. The other 28 patients underwent spiral CT with comparable scanning protocols. The depiction of segmental and subsegmental arteries was analyzed by three independent readers. The contrast enhancement in the main pulmonary artery was measured in each patient. RESULTS: Analysis was performed in 1,120 segmental and 2, 240 subsegmental arteries. One segmental (RA7, P =.010) and two subsegmental (LA7b, P =.029; RA6a+b, P =.038) arteries in paracardiac and basal segments of the lung were depicted significantly better with electron-beam CT. There was no statistically significant difference between electron-beam and spiral CT in the total number of analyzable peripheral arteries depicted. The mean contrast enhancement in the main pulmonary artery was 362 HU in electron-beam CT studies versus 248 HU in spiral CT studies. CONCLUSION: Detailed visualization of peripheral pulmonary arteries is well within the scope of advanced CT techniques. Electron-beam CT has minor advantages in analyzing paracardiac arteries, probably because of reduction of motion artifacts and higher contrast enhancement. Further studies are needed to establish whether electron-beam CT allows a more confident diagnosis of emboli in these vessels.


Assuntos
Angiografia/métodos , Pulmão/irrigação sanguínea , Embolia Pulmonar/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Artérias , Artefatos , Meios de Contraste , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Artéria Pulmonar/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Ácidos Tri-Iodobenzoicos
18.
AJR Am J Roentgenol ; 174(2): 543-7, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10658740

RESUMO

OBJECTIVE: We compared electron beam CT with conventional CT to determine the best method for the assessment of the coronary calcium score. We used conventional CT to examine symptomatic and asymptomatic patients suspected of having coronary artery disease. SUBJECTS AND METHODS: One hundred sixty male patients underwent electron beam CT and helical CT with a pitch of 1 (n = 30) and 2 (n = 30) and using a single-slice mode with (n = 50) and without (n = 50) prospective ECG triggering. In another 50 patients, we determined reproducibility for repeated scanning using electron beam CT. For all images, we derived the calcium score according to the Agatston method. We performed regression analysis and determined mean variability. Mean variability was calculated as the ratio of the absolute difference to the mean of the corresponding calcium scores. RESULTS: The correlation coefficients for electron beam CT and all conventional CT modes were very high (range, 0.93-0.98). The mean variability was highest in the helical mode with a pitch of 2 (61.4%) and lowest for the single-slice mode with prospective ECG triggering (25.4%). For repeated electron beam CT, the correlation coefficient and mean variability were 0.99 and 22.1%, respectively. CONCLUSION: ECG-triggered single-slice conventional CT had the best agreement with electron beam CT calcium scores.


Assuntos
Calcinose/diagnóstico por imagem , Doença das Coronárias/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Elétrons , Humanos , Masculino , Pessoa de Meia-Idade
19.
J Comput Assist Tomogr ; 23(5): 795-9, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10524869

RESUMO

PURPOSE: The purpose of this work was to compare image quality in phantom and patient CT scans acquired by xenon and ceramic CT detector systems. METHOD: High and low contrast resolution and image noise were determined with a standard CT phantom for both detector systems. In patient CT images, the effect on image noise was measured in anatomical regions of interest in the head, lumbar spine, chest, and abdomen. RESULTS: In phantom studies, image noise was significantly lower using ceramic versus xenon detectors. Also, in images of the head and lumbar spine, the signal-to-noise ratio was significantly higher with ceramic than with xenon detectors. In chest scans, ceramic significantly reduced beam-hardening artifacts caused by the thoracic spine. However, in abdominal images, the signal-to-noise ratio was not significantly different between ceramic and xenon detector systems. CONCLUSION: For reduced image noise in CT images of the head, lumbar spine, and chest and high resolution CT, ceramic detector systems appear to be superior to xenon detector systems.


Assuntos
Tomógrafos Computadorizados , Tomografia Computadorizada por Raios X/instrumentação , Artefatos , Encéfalo/diagnóstico por imagem , Cerâmica , Estudos de Avaliação como Assunto , Feminino , Humanos , Vértebras Lombares/diagnóstico por imagem , Masculino , Imagens de Fantasmas/estatística & dados numéricos , Radiografia Abdominal , Radiografia Torácica , Tomógrafos Computadorizados/estatística & dados numéricos , Tomografia Computadorizada por Raios X/métodos , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Xenônio
20.
Radiology ; 212(3): 649-54, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10478227

RESUMO

PURPOSE: To determine whether electrocardiographic (ECG) gating improves image quality of thin-section computed tomographic (CT) scans of the lung obtained with a subsecond CT scanner. MATERIALS AND METHODS: Thin-section CT was performed in 35 patients by using standard techniques. Three additional sections were obtained in each patient with prospective ECG gating at corresponding levels of the paracardiac lung parenchyma. Non-ECG-gated and ECG-gated sections were then rated in blinded fashion by three experienced radiologists for overall image quality, spatial resolution, and diagnostic value and for different types of respiratory and cardiac motion artifacts. RESULTS: ECG gating helped significantly reduce artifacts caused by cardiac motion (i.e., distortion of pulmonary vessels, double images, or blurring of the cardiac border) (P < .05). ECG gating did not reduce respiratory motion artifacts. In patients with heart rates of less than 76 beats per minute, ECG gating significantly improved overall image quality (P = .041). ECG gating was not perceived to increase the diagnostic value of thin-section CT scans. CONCLUSION: ECG gating improves image quality of thin-section CT scans of the lung by reducing cardiac motion artifacts that may mimic disease. It must be established whether ECG gating can help increase the diagnostic accuracy of thin-section CT for the evaluation of subtle parenchymal disease.


Assuntos
Eletrocardiografia/instrumentação , Processamento de Imagem Assistida por Computador/instrumentação , Pneumopatias/diagnóstico por imagem , Intensificação de Imagem Radiográfica/instrumentação , Tomografia Computadorizada por Raios X/instrumentação , Adulto , Idoso , Artefatos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Estudos Prospectivos , Sensibilidade e Especificidade
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