Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 63
Filtrar
1.
PLoS One ; 14(4): e0215093, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30986263

RESUMO

BACKGROUND: Irreversible Electroporation (IRE) is a novel image-guided tissue ablation technology that induces cell death via very short but strong pulsed electric fields. IRE has been shown to have preserving properties towards vessels and nerves and the extracellular matrix. This makes IRE an ideal candidate to treat prostate cancer (PCa) where other treatment modalities frequently unselectively destroy surrounding structures inducing severe side effects like incontinence or impotence. We report the retrospective assessment of 471 IRE treatments in 429 patients of all grades and stages of PCa with 6-year maximum follow-up time. MATERIAL AND FINDINGS: The patient cohort consisted of low (25), intermediate (88) and high-risk cancers (312). All had multi-parametric magnetic resonance imaging, and 199 men had additional 3D-mapping biopsy for diagnostic work-up prior to IRE. Patients were treated either focally (123), sub-whole-gland (154), whole-gland (134) or for recurrent disease (63) after previous radical prostatectomy, radiation therapy, etc. Adverse effects were mild (19.7%), moderate (3.7%) and severe (1.4%), never life-threatening. Urinary continence was preserved in all cases. IRE-induced erectile dysfunction persisted in 3% of the evaluated cases 12 months post treatment. Mean transient IIEF-5-Score reduction was 33% within 12-month post IRE follow-up and 15% after 12 months. Recurrences within the follow-up period occurred in 10% of the treated men, 23 in or adjacent to the treatment field and 18 outside the treatment field (residuals). Including residuals for worst case analysis, Kaplan Maier estimation on recurrence rate at 5 years resulted in 5.6% (CI95: 1.8-16.93) for Gleason 6, 14.6% (CI95: 8.8-23.7) for Gleason 7 and 39.5% (CI95: 23.5-61.4) for Gleason 8-10. CONCLUSION: The results indicate comparable efficacy of IRE to standard radical prostatectomy in terms of 5-year recurrence rates and better preservation of urogenital function, proving the safety and suitability of IRE for PCa treatment. The data also shows that IRE, besides focal therapy of early PCa, can also be used for whole-gland ablations, in patients with recurrent PCa, and as a problem-solver for local tumor control in T4-cancers not amenable to surgery and radiation therapy anymore.


Assuntos
Eletroporação/métodos , Recidiva Local de Neoplasia/terapia , Neoplasias da Próstata/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Neoplasias da Próstata/patologia , Estudos Retrospectivos , Resultado do Tratamento
2.
Proc Natl Acad Sci U S A ; 105(44): 16940-5, 2008 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-18957543

RESUMO

Tumors derived from rat LA7 cancer stem cells (CSCs) contain a hierarchy of cells with different capacities to generate self-renewing spheres and tubules serially ex vivo and to evoke tumors in vivo. We isolated two morphologically distinct cell types with distinct tumorigenic potential from LA7-evoked tumors: cells with polygonal morphology that are characterized by expression of p21/(WAF1) and p63 and display hallmarks of CSCs and elongated epithelial cells, which generate tumors with far less heterogeneity than LA7 CSCs. Serial transplantation of elongated epithelial cells results in progressive loss of tumorigenic potential; tumor heterogeneity; CD44, E-cadherin, and epithelial cytokeratin expression and increased alpha-smooth muscle actin I and vimentin expression. In contrast, serial transplantation of LA7 CSCs can be performed indefinitely and results in tumors that maintain their heterogeneity, consistent with self-renewal and multilineage differentiation potential. Collectively, our data show that polygonal cells are CSCs, whereas epithelial elongated cells are lineage-committed progenitors with tumorigenic potential, and suggest that tumor progenitors, although lacking indefinite self-renewal potential, nevertheless may make a substantial contribution to tumor development. Because LA7 cells can switch between conditions that favor maintenance of pure CSCs vs. differentiation into other tumor cell types, this cell system provides the opportunity to study factors that influence CSC self-renewal and differentiation. One factor, p63, was identified as a key gene regulating the transition between CSCs and early progenitor cells.


Assuntos
Glândulas Mamárias Animais/citologia , Neoplasias Mamárias Experimentais/patologia , Células-Tronco Neoplásicas/citologia , Animais , Diferenciação Celular , Linhagem Celular Tumoral , Linhagem da Célula , Células Clonais , Modelos Animais de Doenças , Feminino , Imuno-Histoquímica , Glândulas Mamárias Animais/metabolismo , Camundongos , Camundongos SCID , Neoplasias/metabolismo , Neoplasias/patologia , Células-Tronco Neoplásicas/metabolismo , Ratos , Células-Tronco/citologia
3.
J Immunoassay Immunochem ; 28(1): 13-23, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17236393

RESUMO

A flow cytometric method for identifying, purifying, and expanding endothelial progenitor cells (EPC) derived from peripheral blood is reported. During our experiments, we found that isolation of viable EPC is not possible by using the standard flow cytometric protocols, since erythrocyte lysing influences cell survival. Furthermore, erythrocyte lysing has a high impact on quantative analysis of EPC with 20% lower numbers compared to no-lyse data. The viability of EPCs was tested with a colony forming test after both lysis based FACS of EPCs and without lysing. CD133 and VEGF-R2 revealed as positive markers for EPC selection and 7-amino actinomycin D (7-AAD) to eliminate dead cells. The few purified CD133+ and VEGF-R2+ cells showed strong colony-forming capacity in a human stem cell methylcellulose based medium (colony assay) when isolated by the no-lyse protocol. The colonies showed the typical shape of early EPC-colonies with round immature cells in the centre and dendritic or spindelcell-shaped peripheral cells, which were also immunologically identified as EPC-derived. Compared to this, erythrocyte lysing reagents destroyed even all sorted EPCs. Summarizing the presented data suggest that the use of erythrocyte lysing reagents is neither suitable for cloning nor for counting of endothelial progenitor cells, and no-lyse protocols should be used.


Assuntos
Antígenos CD/análise , Contagem de Células Sanguíneas/métodos , Separação Celular/métodos , Células Endoteliais/citologia , Citometria de Fluxo/métodos , Glicoproteínas/análise , Peptídeos/análise , Células-Tronco/citologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/análise , Antígeno AC133 , Adulto , Antígenos CD/metabolismo , Células Endoteliais/metabolismo , Feminino , Glicoproteínas/metabolismo , Humanos , Masculino , Peptídeos/metabolismo , Reprodutibilidade dos Testes , Células-Tronco/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo
4.
Cytokine ; 12(9): 1312-21, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10975989

RESUMO

CD163 is a glucocorticoid-inducible member of the scavenger receptor cysteine-rich family of proteins. Previous reports have indicated that CD163 is highly expressed on human macrophages, but found on less than 50% of peripheral blood monocytes. We now show that >99% of all CD14 positive monocytes express CD163 and that monocyte derived dendritic cells express low levels of CD163. We also show that IL-10, like glucocorticoids, induces high CD163 expression on cultured human monocytes. Glucocorticoid induced CD163 expression was not inhibited by anti-IL-10 and was additive with IL-10 treatment, suggesting that glucocorticoids increase CD163 expression by an IL-10 independent mechanism. Other anti-inflammatory cytokines (IL-4 and IL-13) did not increase CD163 expression. In addition, we show that p155 (a previously identified monocyte/macrophage marker of unknown function) shares identity with CD163. Western blots and flow cytometric analysis of HEK 293 cells transfected with the cDNA for CD163 were positive when probed with either mAb RM3/1 (which recognizes CD163) or Mac 2-48 (which defines p155).


Assuntos
Antígenos CD , Antígenos de Diferenciação Mielomonocítica/biossíntese , Interleucina-10/farmacologia , Monócitos/metabolismo , Receptores de Superfície Celular , Regulação para Cima , Animais , Northern Blotting , Western Blotting , Linhagem Celular , Citocinas/farmacologia , DNA Complementar/metabolismo , Células Dendríticas/metabolismo , Dexametasona/farmacologia , Relação Dose-Resposta a Droga , Citometria de Fluxo , Glucocorticoides/farmacologia , Humanos , Interleucina-13/farmacologia , Interleucina-4/farmacologia , Leucócitos Mononucleares/metabolismo , Macrófagos/metabolismo , Camundongos , Fagocitose , RNA Mensageiro/metabolismo , Transcrição Gênica/efeitos dos fármacos , Transfecção
5.
AJR Am J Roentgenol ; 173(1): 95-101, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10397107

RESUMO

OBJECTIVE: The purpose of our study was to investigate the value of respiratory-gated three-dimensional (3D) MR angiography in identifying coronary arteries in healthy volunteers and in patients with proximal coronary artery stenosis and to compare the results with those of conventional coronary angiography. SUBJECTS AND METHODS: Twenty healthy volunteers and 20 patients with coronary artery stenosis were examined on a 1.5-T scanner with a retrospectively respiratory-gated 3D gradient-echo sequence. Visualization of the main coronary arteries was analyzed after curved multiplanar reconstructions. A six-point grading system was used to evaluate 400 vessel segments. The assessment of stenosis was performed by two observers who were unaware of the results of conventional coronary angiography. RESULTS: The proximal, middle, and distal segments of the coronary arteries were completely identified with or without luminal irregularities in 55%, 47%, and 20%, respectively, of the healthy volunteers. For the 20 patients, results were 69%, 44%, and 20%, respectively. For the assessment of coronary artery stenoses (n = 53), sensitivity was 73% and specificity was 50% after evaluation of the MR angiograms of all patients. A sensitivity of 79% and a specificity of 54% were found for evaluation of the MR coronary angiograms, with an image quality score of at least 3 (i.e., artery segments completely identified with major luminal irregularities). CONCLUSION: With the navigator echo MR imaging technique, a complete 3D visualization of the main coronary arteries was possible in cases with high image quality. However, further experience with and improvement of the navigator echo technique we used is necessary for reliable assessment of coronary artery stenosis.


Assuntos
Doença das Coronárias/diagnóstico , Vasos Coronários/patologia , Angiografia por Ressonância Magnética/métodos , Adulto , Idoso , Angiografia Coronária , Doença das Coronárias/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador , Variações Dependentes do Observador , Estudos Retrospectivos , Sensibilidade e Especificidade
8.
Magn Reson Imaging ; 16(7): 799-809, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9811145

RESUMO

Breathing of 100% oxygen was used to challenge vascular autoregulation in 14 mice with either osteosarcomas (n = 6) or mammary carcinomas (n = 8). Reproducible and statistically significant signal intensity changes of -29 +/- 6% to +35 +/- 3% were observed on heavily T2*-weighted images in the tumors during the oxygen challenge. No significant changes were observed in muscle. For the mammary carcinomas a higher percentage of tumor voxels showed significant signal-intensity decrease (31 +/- 8%) compared to the percentage of voxels showing a signal-intensity increase (22 +/- 3%). In contrast, for the osteosarcomas, a higher percentage of tumor voxels showed signal-intensity increase (52 +/- 9%) compared to the percentage of voxels showing signal-intensity decrease (27 +/- 9%). The regional distribution of these signal intensity changes did not correlate with the signal pattern on T1-, T2-,and T2*-weighted and Gd-DTPA enhanced images acquired without breathing 100% oxygen. Most likely, the signal intensity changes represented the inability of the tumor's neovascularization for autoregulation during the oxygen challenge, particularly in hypoxic regions. Although further investigation is needed, the findings that malignant tumor tissue showed signal intensity changes, whereas normal muscle tissue did not, suggests that this technique may prove useful in distinguishing benign from malignant tissue.


Assuntos
Adenocarcinoma/diagnóstico , Neoplasias Ósseas/diagnóstico , Imageamento por Ressonância Magnética/métodos , Neoplasias Mamárias Experimentais/diagnóstico , Osteossarcoma/diagnóstico , Oxigênio , Administração por Inalação , Animais , Meios de Contraste , Feminino , Gadolínio DTPA , Processamento de Imagem Assistida por Computador , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Transplante de Neoplasias , Oxigênio/administração & dosagem , Reprodutibilidade dos Testes
9.
Magn Reson Imaging ; 16(4): 393-404, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9665550

RESUMO

PURPOSE: To implement and evaluate the accuracy of non-invasive temperature mapping using MRI methods based on the chemical shift (CS) and T1 relaxation in media of various heterogeneity during focal (laser) and external thermal energy deposition. MATERIALS AND METHODS: All measurements were performed on a 1.5 T superconducting clinical scanner using the temperature dependence of the water proton chemical shift and the T1 relaxation time. Homogeneous gel and heterogeneous muscle phantoms were heated focally with a fiberoptic laser probe and externally of varying degree ex vivo by water circulating in a temperature range of 20-50 degrees C. Magnetic resonance imaging data were compared to simultaneously recorded fiberoptic temperature readings. RESULTS: Both methods provided accurate results in homogeneous media (turkey) with better accuracy for the chemical shift method (CS:+/-1.5 degrees C, T1:+/-2.0 degrees C). In gel, the accuracy with the CS method was +/-0.6 degrees C. The accuracy decreased in heterogeneous media containing fat (T1:+/-3.5 degrees C, CS: +5 degrees C). In focal heating of turkey muscle, the accuracy was within 1.5 degrees C with the T1 method. CONCLUSION: Temperature monitoring with the chemical shift provides better results in homogeneous media containing no fat. In fat tissue, the temperature calculation proved to be difficult.


Assuntos
Temperatura Corporal , Articulações/fisiologia , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética/métodos , Músculo Esquelético/fisiologia , Animais , Processamento de Imagem Assistida por Computador , Imagens de Fantasmas , Reprodutibilidade dos Testes , Suínos , Termografia/métodos , Perus
10.
MAGMA ; 5(3): 247-54, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9351029

RESUMO

This study evaluated the potential of contrast-enhanced digital-subtraction magnetic resonance angiography (CE-DS-MRA) for noninvasive angiographic delineation of the arterial supply of the penis in patients with erectile dysfunction. After induction of an erection with prostaglandin E, a three-dimensional fast imaging with steady-state precision (FISP) sequence with TE of 1.8-2 milliseconds, TR of 4.4-5 milliseconds, and flip angle of 40 degrees-60 degrees was used to obtain high-resolution angiograms of the pelvis and penis during the injection of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) 0.3 mmol/kg body weight, within 30-50 seconds. DS maximum intensity projections (MIPs) and multiplanar reconstructions (MPRs) were compared with clinical work-up and directional Doppler ultrasound in 11 patients. In all 11 patients (100%), the arterial supply of the penis could be delineated from the aortic bifurcation via the iliac and internal pudendal arteries to the dorsal and deep penile arteries. Of the 22 internal pudendal arteries, 6 (27%) were occluded on CE-DS-MRA and 5 (23%) had stenoses, of which 4 (18%) were greater than 50%. In 7 patients (64%) good correlation between CE-DS-MRA and clinical findings and/or Doppler ultrasound was found; in 2 patients (18%), the correlation was moderate, and in 2 patients (18%) results were discrepant. In 6 patients (55%), MRA provided additional information to the clinical and Doppler ultrasound work-up. CE-DS-MRA can delineate small vessels such as the internal pudendal and penile arteries and thus has the potential to become a noninvasive angiography method in the work-up of erectile impotence.


Assuntos
Disfunção Erétil/diagnóstico , Gadolínio , Angiografia por Ressonância Magnética/métodos , Pelve/patologia , Ereção Peniana/fisiologia , Artérias/patologia , Estudos de Avaliação como Assunto , Humanos , Artéria Ilíaca/patologia , Masculino , Pelve/diagnóstico por imagem , Pênis/irrigação sanguínea , Pênis/diagnóstico por imagem , Intensificação de Imagem Radiográfica , Cintilografia , Ultrassonografia Doppler/métodos
11.
Radiology ; 205(1): 278-82, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9315000

RESUMO

Depiction of small-bowel pathologic conditions was optimized with use of a negative luminal contrast agent, spectral fat suppression, and gadolinium enhancement in an excised gut phantom. The method was applied in nine patients in conjunction with standard enteroclysis examinations. Bulk susceptibility effects of oral magnetic particles were canceled with use of a diamagnetic methylcellulose suspension. In the ileum, fat suppression and contrast between bowel wall and lumen was judged good or excellent in eight and nine patients, respectively. In eight of nine patients, additional mesenteric findings were depicted.


Assuntos
Meios de Contraste/administração & dosagem , Gadolínio/administração & dosagem , Enteropatias/diagnóstico , Intestino Delgado/patologia , Ferro/administração & dosagem , Imageamento por Ressonância Magnética , Meglumina/administração & dosagem , Compostos Organometálicos/administração & dosagem , Óxidos/administração & dosagem , Ácido Pentético/análogos & derivados , Administração Oral , Adolescente , Adulto , Animais , Bovinos , Combinação de Medicamentos , Feminino , Óxido Ferroso-Férrico , Gadolínio DTPA , Humanos , Técnicas In Vitro , Masculino , Pessoa de Meia-Idade , Ácido Pentético/administração & dosagem
12.
Radiologe ; 37(7): 501-7, 1997 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-9340683

RESUMO

Contrast enhanced (CE) magnetic resonance angiography affords angiographic depiction of extended vascular territories with high quality and diagnostic value. A prerequisite is the fast acquisition of a three-dimensional gradient-echo data set during the injection of a bolus of a T1-shortening contrast agent. We describe the dependence of the quality of CE-MRA on technical parameters of different MR-scanners and consider some fundamental facts and practical guidelines concerning the contrast agent injection.


Assuntos
Doenças Cardiovasculares/diagnóstico , Meios de Contraste , Aumento da Imagem/instrumentação , Angiografia por Ressonância Magnética/instrumentação , Simulação por Computador , Desenho de Equipamento , Humanos , Processamento de Imagem Assistida por Computador/instrumentação , Imagens de Fantasmas , Sensibilidade e Especificidade
13.
Radiologe ; 37(7): 539-46, 1997 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-9340687

RESUMO

Contrast enhanced (CE) magnetic resonance angiography (MRA) provides high resolution angiograms within 20-40 sec. The technique is based on the acquisition of heavily T1-weighted three-dimensional (3D) gradient-echo data sets (FISP) with ultrashort echo-(< 2ms) and repetition times (< 5 ms) during arterial phase of an intravenously injected bolus of a T1-shortening agent such as Gd-DTPA. For MR-angiography of abdominal vessels CE-MRA is better suited than "time-of flight" (TOF) and phase-contrast (PC) MRA because motional artifacts can be obviated with breath-held acquisitions. We have optimised the technique and evaluated its potential for angiography of the abdominal aorta and its branches as well as the portal vein and its tributaries. Whilst CE-MRA provides reliable diagnostic accuracy in the aorta and the proximal sections of its branches, small peripheral arteries cannot be assessed accurately. The portal vein and its tributaries can often be depicted better with CE-MRA than with conventional angiography but, like conventional angiography, CE-MRA is hampered by slow and reversed flow, conditions under which TOF or "true FISP" MRA may perform bst. We have also investigated FLASH-echo-planar imaging (EPI) hybrid techniques, a further technical development which due to shorter acquisition times of 12-15 sec. allows semi-dynamic imaging of the arterial and venous phase and provide better vessel contrast due to the use of fat-suppression.


Assuntos
Abdome/irrigação sanguínea , Meios de Contraste , Gadolínio , Angiografia por Ressonância Magnética , Doenças Vasculares/diagnóstico , Aorta Abdominal/patologia , Doenças da Aorta/diagnóstico , Arteriopatias Oclusivas/diagnóstico , Velocidade do Fluxo Sanguíneo , Humanos , Aumento da Imagem , Processamento de Imagem Assistida por Computador , Veia Porta/patologia
14.
Radiologe ; 37(5): 372-7, 1997 May.
Artigo em Alemão | MEDLINE | ID: mdl-9312780

RESUMO

PURPOSE: Purpose of this study was to test a triple slice saturation recovery turbo FLASH sequence for myocardial perfusion imaging. In addition data-evaluation-tools for qualitative and quantitative perfusion parameters are presented and preliminary tested. MATERIAL AND METHODS: We examined 8 healthy volunteers and 4 patients with myocardial infarction. Parameters of the saturation recovery turbo FLASH sequence were as follows: TR = 2.5 msec, TE = 1.2 msec, alpha = 8 degrees, 3 slices, thickness 10 mm. For data analysis signal-intensity time curves were calculated pixel by pixel and evaluated for signal-intensity-increase over baseline and signal-intensity-upslope. Images were displayed color-coded. For quantitative data analysis we used the indicator dilution theory and developed a deconvolution algorithm which takes the arterial input function into account to calculate the myocardial mean transit time (MTT). RESULTS: The color-coded parametermaps showed uniform conditions in normal myocardium of volunteers, but reduced signal-intensity-increase over baseline and signal-intensity-upslope for infarcted areas in patients. The MTTs calculated using our algorithm were significantly shorter than those assessed with previous methods and matched better with values derived from literature. Infarcted areas show prolonged MTTs in comparison to normal myocardium. CONCLUSION: A triple slice saturation recovery turbo FLASH sequence is suitable for myocardial perfusion imaging. Color-coded parametermaps can visualize hypoperfused areas. For calculating myocardial MTTs using indicator dilution therapy a deconvolution algorithm is necessary.


Assuntos
Circulação Coronária/fisiologia , Doença das Coronárias/diagnóstico , Processamento de Imagem Assistida por Computador/instrumentação , Imageamento por Ressonância Magnética/instrumentação , Infarto do Miocárdio/diagnóstico , Adulto , Algoritmos , Doença das Coronárias/fisiopatologia , Feminino , Humanos , Técnicas de Diluição do Indicador/instrumentação , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/fisiopatologia , Sensibilidade e Especificidade
15.
Eur Radiol ; 7(4): 520-3, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9204331

RESUMO

In this case of choledocholithiasis in a patient with previous Billroth-II surgery and cholecystectomy we demonstrate the advantages of a heavily T2-weighted half-Fourier turbo-spin-echo (HASTE) sequence. This technique allows thin-slice snapshot imaging with 1.4 s per slice eliminating motion artifacts and still has the necessary heavy T2-weighting to depict biliary fluid with high contrast. In the presented case endoscopic retrograde cholangiography (ERCP) could not be performed prior to MRI due to technical problems. In a second attempt, ERCP was successful and a common bile duct stone as diagnosed by MRI before could be removed. We conclude that HASTE snapshot MR cholangiography can be used as a clinically valuable tool when other noninvasive methods are not diagnostic.


Assuntos
Ductos Biliares/patologia , Cálculos Biliares/diagnóstico , Imageamento por Ressonância Magnética , Complicações Pós-Operatórias/diagnóstico , Estômago/cirurgia , Idoso , Cálculos Biliares/etiologia , Humanos , Masculino
16.
Radiologe ; 37(1): 89-93, 1997 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-9157481

RESUMO

PURPOSE: To develop and implement a method to obtain digital subtraction (DS) spiral computed tomography angiograms (SCTA) in order to avoid superimposition of bony structures and vascular calcifications on SCTA maximum intensity projections (MIPs) and shaded surface display (SSD). METHOD: Two SCTA data sets, one before and one during the injection of a contrast agent bolus, were obtained with identical scan parameters. Since ordinary subtraction of the two data sets fails to reliably separate bones and calcifications from the vascular lumen because of motion, a so-called elastic subtraction procedure was designed to correct 3D misregistration between the two data sets. It automatically accommodates for local position changes between baseline and contrast images, including regionally inconsistent non-linear displacements and arbitrary rotations. This method was tested in seven patients and evaluated against ordinary DS in terms of image quality and artifacts. RESULTS: In all patients "elastic" CTSA proved superior to ordinary DS. It provides automated and reliable separation of vessels from bones and calcifications. This improves the delineation of vessels in the neck and the skull base and of intracranial vessels. DS-SCTA facilitates MIPs and SSD without artifacts introduced by thresholding. CONCLUSION: Elastic DS-SCTA is a robust method for automated unmasking of vessels from bones and warrants clinical trials and comparison with MR- and conventional angiography.


Assuntos
Algoritmos , Angiografia Digital/instrumentação , Encéfalo/irrigação sanguínea , Angiografia Cerebral/instrumentação , Transtornos Cerebrovasculares/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/instrumentação , Tomografia Computadorizada por Raios X/instrumentação , Artefatos , Sistemas Computacionais , Humanos
17.
Invest Radiol ; 32(1): 1-6, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9007641

RESUMO

RATIONALE AND OBJECTIVES: The authors compare the value of a new circularly polarized body array coil (BAC) system with a standard body coil (BC) for high-resolution magnetic resonance imaging of the female pelvis. METHODS: Twenty patients with cervical cancer were examined with a BC and BAC. Imaging parameters were kept constant (sagittal T2-weighted turbo spin-echo: repetition time = 4000 mseconds; effective echo time = 99 mseconds; 160 x 160 mm field of view; 256 x 256 matrix; 0.63 x 0.63 mm pixel size; 4-mm slice thickness). Images were scored for lesion-to-organ delineation and overall image quality/ artifacts using a scale from 5 to 1 (excellent to poor). Signal-to-noise (S/N) ratios for different tissues (tumor, uterus, vagina, rectum, muscle, and fat) as well as contrast-to-noise (C/N) ratios between tumor and (1) uterus, (2) vagina, and (3) rectum were calculated. Magnetic resonance tumor staging was performed according to the International Federation of Gynecology and Obstetrics (FIGO) classification. RESULTS: Using the BAC, S/N and C/N ratios increased significantly compared with the BC (S/N: 2.7-3.4-fold increase for all organs evaluated, P < 0.001: C/N: tumor versus uterus 2.4-fold, P < 0.01; tumor versus vagina 6.1-fold, P < 0.001; tumor versus rectum 3.1-fold, P < 0.01). This resulted in an improved overall image quality (average ratings: BAC-4.3 points; BC-2.6 points; P < 0.001). Lesion-to-organ delineation (average ratings: BAC 4.3-4.1 points, BC 3.5-2.7 points for all organs evaluated; P < 0.001) was increased noticeably on BAC images. No significant difference was found for staging accuracy. CONCLUSIONS: Circularly polarized BAC provide superior S/N and C/N ratios and improve lesion conspicuity compared with standard BC.


Assuntos
Imageamento por Ressonância Magnética/métodos , Pelve/patologia , Neoplasias Uterinas/diagnóstico , Adulto , Idoso , Feminino , Humanos , Aumento da Imagem/instrumentação , Pessoa de Meia-Idade , Estudos Prospectivos
18.
J Neurol Neurosurg Psychiatry ; 61(6): 632-5, 1996 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8971115

RESUMO

OBJECTIVES: To compare the sensitivity of fast spin echo (FSE) and of fast fluid attenuated inversion recovery (fast FLAIR) in detecting spinal cord lesions in multiple sclerosis. METHODS: With a 1.5 Tesla machine and a multicoil receiver array, FSE images (with two different pixel sizes) and fast FLAIR images of the spinal cord were obtained from 13 patients with multiple sclerosis. RESULTS: Twenty three lesions (10 cervical, 12 thoracic, and one lumbar) were found in seven patients (54%) using FSE with the larger pixel size. Seventeen lesions (seven cervical and 10 thoracic) were detected in the same seven patients using FSE with smaller pixel size. Nine lesions (five cervical and four thoracic) were found using fast FLAIR in six patients (46%). All the lesions found using fast FLAIR were detected using the other two techniques and all the lesions detected by FSE with smaller pixel size were detected using FSE and greater pixel size. CONCLUSION: Fast FLAIR sequences detect substantially fewer cord lesions in patients with multiple sclerosis.


Assuntos
Esclerose Múltipla/patologia , Medula Espinal/patologia , Adulto , Imagem Ecoplanar , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino
19.
Radiologe ; 36(9): 722-31, 1996 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-8999449

RESUMO

PURPOSE: To assess the clinical value of MRI in patients with benign prostatic hyperplasia (BPH) before, during, and after interstitial laser-induced thermotherapy (LITT) of the prostate. METHODS: Ten patients with symptomatic BPH had MRI examinations of the prostate 48 h before and after LITT. Online monitoring with MRI at 1.5 T of interstitial Nd:YAG laser energy deposition in the prostate was performed in two patients, repeating a T1-weighted FLASH sequence (TR 100 ms, TE 5 ms, flip angle 90 degrees) every 20 s. Follow-up MRI examinations 2-3 weeks, 6-8 weeks, and 6-12 months after LITT were carried out in eight patients, using T2-weighted FSE images and contrast-enhanced T1-weighted SE images. RESULTS: The prostate was well delineated in all patients on T2-weighted FSE images, with a rather homogeneous peripheral gland and an inhomogeneous central gland. Volume measurements yielded reproducibilities of 3.2%-4.7%. Signal intensity in the FLASH sequence decreased during LITT, both in the prostate in vivo and in specimens of bovine prostate and seminal vesicles in vitro, with signal developments running in parallel. Areas of energy deposition and signal alteration were not sharply delineated. The latter margin of the laser-induced lesions could not be predicted from the FLASH images, while the tip of the laser fibre was easily recognized. Contrast-enhanced T1-weighted MR images immediately after LITT clearly demarcated low signal intensity laser lesions from high signal intensity surrounding prostate tissue. Follow-up examinations showed a decrease of 20% of prostate volume over a period of 6-12 months after LITT. Correlation between prostate volume development and lesion volume alteration was 0.85-0.90 (P = 0.002-0.007) at all follow-up times. CONCLUSIONS: MRI allows rather precise recognition of intraprostatic alterations after LITT, including volume changes over a period of up to 1 year after therapy that can be predicted immediately after LITT. While laser energy deposition in the prostate can be monitored by MRI with T1-weighted FLASH sequences as a function of temperature alteration, it is not possible to determine the lesion margins immediately from the FLASH images. Online temperature development map generation will be necessary to influence on-going LITT procedures with MRI.


Assuntos
Hipertermia Induzida/instrumentação , Imageamento por Ressonância Magnética/instrumentação , Neoplasias da Próstata/terapia , Idoso , Seguimentos , Humanos , Lasers , Masculino , Pessoa de Meia-Idade , Próstata/patologia , Neoplasias da Próstata/patologia , Resultado do Tratamento
20.
MAGMA ; 4(3-4): 231-40, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-9220412

RESUMO

PURPOSE: To implement and evaluate two robust methods for T1- and T2-weighted snapshot imaging of the heart with data acquisition within a single heart beat and suppression of blood signal. METHODS: Both T1- and T2-weighted diastolic images of the heart can be obtained with half Fourier single-shot turbo spin echo (HASTE) and turbo fast low-angle shot (turboFLASH) sequences, respectively, in less than 350 ms. Signal from flowing blood in the ventricles and large vessels can be suppressed by a preceding inversion recovery preparing pulse pair (PRESTO). Fifteen volunteers and five patients have been evaluated quantitatively for signal-to-noise ratio (SNR) contrast-to-noise ratio (CNR) and flow void and qualitatively for image quality, artifacts, and black-blood effect. RESULTS: Both PRESTO-HASTE and PRESTO-turboFLASH achieved consistently good image quality and blood signal suppression. In contrast to gradient-echo (GRE) echo-planar imaging techniques, (EPI) HASTE and turboFLASH are much less sensitive to local susceptibility differences in the thorax, resulting in a more robust imaging technique without the need for time-consuming system tuning. Compared to standard spin-echo sequences with cardiac triggering. HASTE and turboFLASH have significantly shorter image acquisition times and are not vulnerable to respiratory motion artifacts. CONCLUSION: PRESTO-HASTE and PRESTO-turboFLASH constitute suitable methods for fast and high-quality cardiac magnetic resonance imaging (MRI).


Assuntos
Coração/anatomia & histologia , Imageamento por Ressonância Magnética/métodos , Sangue , Estudos de Avaliação como Assunto , Fibrossarcoma/diagnóstico , Análise de Fourier , Átrios do Coração/anatomia & histologia , Neoplasias Cardíacas/diagnóstico , Ventrículos do Coração/anatomia & histologia , Humanos , Processamento de Imagem Assistida por Computador/métodos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Imageamento por Ressonância Magnética/estatística & dados numéricos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...