Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Quant Imaging Med Surg ; 11(9): 4056-4073, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34476189

RESUMO

BACKGROUND: This study sought to validate the clinical utility of multimodal magnetic resonance imaging (MRI) techniques in the assessment of neurodegenerative disorders. We intended to demonstrate that advanced neuroimaging techniques commonly used in research can effectively be employed in clinical practice to accurately differentiate heathy aging and dementia subtypes. METHODS: Twenty patients with dementia of the Alzheimer's type (DAT) and 18 patients with Parkinson's disease dementia (PDD) were identified using gold-standard techniques. Twenty-three healthy, age and sex matched control participants were also recruited. All participants underwent multimodal MRI including T1 structural, diffusion tensor imaging (DTI), arterial spin labeling (ASL), and magnetic resonance spectroscopy (MRS). MRI modalities were evaluated by trained neuroimaging readers and were separately assessed using cross-validated, iterative discriminant function analyses with subsequent feature reduction techniques. In this way, each modality was evaluated for its ability to differentiate patients with dementia from healthy controls as well as to differentiate dementia subtypes. RESULTS: Following individual and group feature reduction, each of the multimodal MRI metrics except MRS successfully differentiated healthy aging from dementia and also demonstrated distinct dementia subtypes. Using the following ten metrics, excellent separation (95.5% accuracy, 92.3% sensitivity; 100.0% specificity) was achieved between healthy aging and neurodegenerative conditions: volume of the left frontal pole, left occipital pole, right posterior superior temporal gyrus, left posterior cingulate gyrus, right planum temporale; perfusion of the left hippocampus and left occipital lobe; fractional anisotropy (FA) of the forceps major and bilateral anterior thalamic radiation. Using volume of the left frontal pole, right posterior superior temporal gyrus, left posterior cingulate gyrus, perfusion of the left hippocampus and left occipital lobe; FA of the forceps major and bilateral anterior thalamic radiation, neurodegenerative subtypes were accurately differentiated as well (87.8% accuracy, 95.2% sensitivity; 85.0% specificity). CONCLUSIONS: Regional volumetrics, DTI metrics, and ASL successfully differentiated dementia patients from controls with sufficient sensitivity to differentiate dementia subtypes. Similarly, feature reduction results suggest that advanced analyses can meaningfully identify brain regions with the most positive predictive value and discriminant validity. Together, these advanced neuroimaging techniques can contribute significantly to diagnosis and treatment planning for individual patients.

2.
Neurol Clin Pract ; 11(3): e294-e302, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34484904

RESUMO

OBJECTIVE: The pursuit of an effective therapeutic intervention for dementia has inspired interest in the class of medications known as tyrosine kinase inhibitors such as bosutinib. METHODS: Thirty-one patients with probable Alzheimer dementia or Parkinson spectrum disorder with dementia completed 12 months of bosutinib therapy and an additional 12 months of follow-up. The Clinical Dementia Rating scale (as estimated by the Quick Dementia Rating System [QDRS]) was the primary cognitive status outcome measure. Secondary outcome measures included the Repeatable Battery Assessment of Neuropsychological Status (RBANS) and the Montreal Cognitive Assessment. Cox regression methods were used to compare results with population-based estimates of cognitive decline. RESULTS: The present article reports on cognitive outcomes obtained at 12 months for 31 participants and up to 24 months for a 16-participant subset. Safety and tolerability of bosutinib were confirmed among the study population (Mage = 73.7 years, SDage = 14 years). Bosutinib was associated with less worsening in Clinical Dementia Rating (CDR) scores (hazard ratio = -0.62, p < 0.001, 95% confidence interval [CI]: -1.02 to -0.30) and less decline in RBANS performance (hazard ratio = -3.42, p < 0.001, 95% CI: -3.59 to -3.72) during the year of treatment than population-based estimates of decline. In the 24-month follow-up, wherein 16 patients were observed after 1 year postintervention, 31.2% of participants exhibited worsened CDR levels compared with their 12-month performances. CONCLUSIONS: Results support an overall positive outcome after 1 year of bosutinib. Future studies should explore the relationship between tyrosine kinases and neurodegenerative pathology as well as related avenues of treatment.

3.
Invest Radiol ; 42(10): 665-70, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17984762

RESUMO

PURPOSE: X-ray angiography is currently the standard test for the assessment of coronary artery disease. A substantial minority of patients referred for coronary angiography have no significant coronary artery disease. The purpose of this work was the evaluation of the accuracy of a three-dimensional (3D) breathhold coronary magnetic resonance angiography (MRA) technique in detecting hemodynamically significant coronary artery stenoses in a patient population with x-ray angiographic correlation. MATERIALS AND METHODS: Sequential subjects (n = 33, M/F = 22/11, average age = 57) who were referred for conventional coronary angiography were enrolled in the study. The study protocol was approved by our institutional review board. Each subject gave written informed consent. Volume-targeted 3D breathhold coronary artery scans with ECG-triggered, segmented True Fast Imaging with Steady-state Precession (TrueFISP) were acquired for the left main (LM), left anterior descending (LAD), and right coronary arteries (RCAs). Coronary MRA was evaluated with conventional angiography as the gold standard. RESULTS: The overall sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) for diagnosing any hemodynamically significant coronary artery disease (> or =50% diameter reduction) with coronary MRA was 87%, 57%, 72%, 68%, and 80%, respectively. The sensitivity of the technique in the LM, LAD, and RCA was 100%, 83%, and 100%, respectively. The NPV of the technique in the LM, LAD, and RCA was 100%, 82%, and 100%, respectively. CONCLUSIONS: Three-dimensional breathhold True Fast Imaging with Steady-state Precession is a promising technique for coronary artery imaging. It has a relatively high sensitivity and NPV. Results of this study warrant further technical improvements and clinical evaluation of the technique.


Assuntos
Doença da Artéria Coronariana/diagnóstico , Vasos Coronários/patologia , Angiografia por Ressonância Magnética/instrumentação , Adulto , Idoso , Arteriosclerose/diagnóstico , Arteriosclerose/fisiopatologia , Angiografia Coronária , Doença da Artéria Coronariana/fisiopatologia , Feminino , Humanos , Angiografia por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Sensibilidade e Especificidade
4.
J Am Coll Cardiol ; 45(7): 1104-8, 2005 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-15808771

RESUMO

OBJECTIVES: We sought to evaluate whether infarct size characterization by cardiac magnetic resonance imaging (MRI) is a better predictor of inducible ventricular tachycardia (VT) than left ventricular ejection fraction (LVEF). BACKGROUND: Inducibility of VT at electrophysiologic study (EPS) and low LVEF can identify patients with a substrate for VT. Magnetic resonance imaging has been shown to identify, with high precision, areas of myocardial infarction and may therefore be a better tool to evaluate for a substrate for VT. METHODS: We studied 48 patients with known coronary artery disease who were referred for EPS using cine and gadolinium-enhanced MRI. Wall motion and infarct characteristics were determined blindly and compared among patients with no inducible ventricular arrhythmias (n = 21), those with inducible monomorphic VT (MVT, n = 18), and those with either inducible polymorphic VT or ventricular fibrillation (n = 9). RESULTS: Patients with MVT had larger infarcts than patients who did not have inducible arrhythmias (mass: 49 +/- 5 g [SE] vs. 28 +/- 5 g, p < 0.005; surface area: 172 +/- 15 cm(2) vs. 93 +/- 14 cm(2), p < 0.0005). Patients with polymorphic VT/fibrillation had intermediate values (mass: 36 +/- 7 g; surface area: 115 +/- 22 cm(2)). Ejection fraction was inversely related to infarct mass and surface area, with R(2) values ranging from 0.21 to 0.27. Logistic regression and receiver-operating characteristic analysis demonstrated that infarct mass and surface area were better predictors of inducibility of MVT than LVEF. CONCLUSIONS: Infarct surface area and mass, as measured by cardiac MRI, are better identifiers of patients who have a substrate for MVT than LVEF. Further evaluation of infarct size characterization by cardiac MRI as a predictor of sudden cardiac death is warranted.


Assuntos
Imageamento por Ressonância Magnética/métodos , Infarto do Miocárdio/patologia , Taquicardia Ventricular/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/complicações , Infarto do Miocárdio/fisiopatologia , Valor Preditivo dos Testes , Curva ROC , Sensibilidade e Especificidade , Volume Sistólico , Taquicardia Ventricular/complicações , Taquicardia Ventricular/fisiopatologia
5.
Acad Radiol ; 9(12): 1407-18, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12553352

RESUMO

RATIONALE AND OBJECTIVES: The purpose of this study was to implement ultrafast, multiphase three-dimensional (3D) magnetic resonance (MR) angiography and perfusion imaging after bolus injection of contrast medium to generate preliminary validation of parameters in a pig model and to illustrate potential applications in patients with lung abnormalities. MATERIALS AND METHODS: Five healthy volunteers, five patients, and three pigs underwent rapid, time-resolved pulmonary MR angiography and perfusion imaging on a 1.5-T MR imager. All patients had undergone correlative computed tomographic or conventional angiography. The pulse sequence was a 3D spin-warp, gradient-echo acquisition with a repetition time of 1.6 msec and an echo time of 0.6 msec. Each 3D acquisition lasted 2-3 seconds, and 8-16 sequential measurements were made in each study. Artificial pulmonary emboli were generated in pigs with gelatin sponge. All patients had diseases of the pulmonary circulation (as confirmed with other studies). RESULTS: Multiphasic, time-resolved pulmonary parenchymal enhancement was demonstrated in all healthy subjects and animals. All segmental (n = 100) and subsegmental (n = 200) branches were identified in the healthy subjects. Perfusion deficits were clearly demonstrated in all pigs after gelatin embolization. Perfusion defects were identified in two patients with lung disease. Abnormalities of the pulmonary vasculature were clearly identified in the patient group. CONCLUSION: Dynamic time-resolved 3D pulmonary MR angiography and perfusion imaging is feasible in humans as well as in animals. Induced perfusion deficits are identifiable after artificial embolization in pigs. Combined pulmonary MR angiography and parenchymal (perfusion) imaging may improve evaluation of the pulmonary circulation in a variety of conditions.


Assuntos
Imageamento Tridimensional , Angiografia por Ressonância Magnética , Perfusão/métodos , Adulto , Idoso , Animais , Aorta Torácica/diagnóstico por imagem , Arteriopatias Oclusivas/diagnóstico , Malformações Arteriovenosas/diagnóstico , Biópsia , Feminino , Ventrículos do Coração/diagnóstico por imagem , Humanos , Pulmão/irrigação sanguínea , Pulmão/diagnóstico por imagem , Pneumopatias/diagnóstico , Angiografia por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Artéria Pulmonar/diagnóstico por imagem , Artéria Pulmonar/patologia , Circulação Pulmonar/fisiologia , Veias Pulmonares/diagnóstico por imagem , Veias Pulmonares/patologia , Intensificação de Imagem Radiográfica , Suínos , Fatores de Tempo , Tomografia Computadorizada por Raios X
6.
Acad Radiol ; 9(1): 50-9, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11918359

RESUMO

RATIONALE AND OBJECTIVES: The authors compared diagnostic accuracy of maximum intensity projection (MIP), multiplanar reformatting (MPR), and three-dimensional (3D) volume rendering (VR) in the evaluation of gadolinium-enhanced 3D magnetic resonance (MR) angiography of the renal arteries. They hypothesized that VR is as accurate as or more accurate than MIP and MPR at depicting renal artery stenosis. MATERIALS AND METHODS: The study group comprised 28 consecutive patients who underwent gadolinium-enhanced 3D MR angiography of the renal arteries. Studies were postprocessed to display images in MIP, MPR, and VR formats. Digital subtraction angiography (DSA), when performed (nine of 28 patients), was the standard for comparison. For each main renal artery, an estimate of percentage stenosis was made for any stenoses detected by three independent radiologists. For calculation of sensitivity, specificity, and accuracy, MR angiographic stenosis estimates were categorized as mild (0%-39%), moderate (40%-69%), or severe (> or = 70%). DSA stenosis estimates of 70% or greater were considered hemodynamically significant. RESULTS: Analysis of variance demonstrated MIP estimates of stenosis were statistically greater than VR estimates in two readers and greater than MPR estimates in all readers for all patients. MIP images also showed the largest mean difference from DSA stenosis estimates for all three readers. For both VR and MPR, mean differences between MR angiographic stenoses estimates and DSA estimates reached significance for only one reader, whereas, for MIP versus DSA, mean differences reached significance for all three readers. Although not statistically significant compared with DSA, accuracies of VR (87%) and MPR (89%) were greater than that of MIP (81%). CONCLUSION: In this pilot study, MIP was the least accurate of the three image display algorithms tested. VR and MPR yielded similar values for each method of comparison.


Assuntos
Meios de Contraste , Gadolínio DTPA , Angiografia por Ressonância Magnética/métodos , Obstrução da Artéria Renal/diagnóstico , Adulto , Idoso , Algoritmos , Análise de Variância , Feminino , Humanos , Aumento da Imagem , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Sensibilidade e Especificidade
7.
Radiology ; 238(2): 489-96, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16436813

RESUMO

PURPOSE: To test the hypothesis that the technical success rates, complication rates, and procedural times for magnetic resonance (MR) imaging-guided percutaneous transluminal angioplasty (PTA) and conventional (x-ray) fluoroscopy-guided PTA for treatment of renal artery stenosis are similar. MATERIALS AND METHODS: The study was animal care and use committee approved. After surgically inducing bilateral renal artery stenosis in 11 swine, the authors performed baseline digital subtraction angiography. They transferred each animal to a 1.5-T MR imaging unit and randomly decided which artery would be treated with MR-guided PTA. With MR imaging guidance, angioplastic devices were tracked by using active and passive techniques. Vascular depiction was achieved by using catheter-directed MR angiography. Stenotic vessels were dilated by using 5-6-mm-diameter balloon catheters. PTA was then performed in the contralateral artery by using conventional fluoroscopy-guided techniques. With the intention to treat, the authors compared the technical success (residual stenosis < 50%) rates, complication rates, and procedural times for each guidance method. They compared technical successes and complications by using the McNemar test and procedural times by using a paired t test, with P < .05 indicating a significant difference. RESULTS: The authors successfully dilated nine (82%) of 11 renal arteries with MR guidance and all 11 arteries (100%) with conventional fluoroscopic guidance. The difference was not significant (P = .5). Complications occurred in three (27%) arteries with MR guidance and in one (9%) artery with fluoroscopic guidance, with no significant differences (P = .5). The mean MR-guided PTA procedural time was 46 minutes longer than the fluoroscopy-guided PTA procedural time; this difference was significant (P = .01). CONCLUSION: In a small cohort of swine, the authors did not observe a significant difference between MR imaging- and conventional fluoroscopy-guided renal artery PTA in terms of success and complication rates. However, no evidence of similarity between the techniques should be assumed. Procedural times differed significantly.


Assuntos
Angioplastia/métodos , Imageamento por Ressonância Magnética , Obstrução da Artéria Renal/diagnóstico por imagem , Obstrução da Artéria Renal/diagnóstico , Angioplastia/efeitos adversos , Animais , Fluoroscopia , Estudos Prospectivos , Distribuição Aleatória , Suínos
8.
Magn Reson Med ; 54(5): 1094-9, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16217784

RESUMO

The accuracy of a two-step interventional MRI protocol to quantify coronary artery disease was compared to the clinical gold standard, X-ray angiography. Studies were conducted in nine swine with a surgically induced stenosis in the proximal left circumflex coronary artery. The two-step protocol consisted of catheter-directed magnetic resonance angiography (MRA), which was first used to localize the stenosis, followed by MRI cross-sectional images to quantify the degree of stenosis without the use of contrast agent. Line signal intensity profiles were drawn across the vessel diameter at the stenosis site and proximal to the stenosis for each data set to measure percentage stenosis for each animal. Catheter-directed MRA successfully detected eight of nine stenoses. Cross-sectional MRI accurately quantified each stenosis, with strong agreement to the measurements made using X-ray fluoroscopy (intraclass correlation coefficient = 0.955; P < 0.05). This study demonstrates that in the future interventional MRI may be an alternative to X-ray angiography for the detection and quantification of coronary artery disease.


Assuntos
Angiografia/métodos , Cateterismo Cardíaco/métodos , Estenose Coronária/diagnóstico por imagem , Estenose Coronária/patologia , Fluoroscopia/métodos , Angiografia por Ressonância Magnética/métodos , Animais , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Suínos
9.
J Comput Assist Tomogr ; 28(6): 852-6, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15538164

RESUMO

Cardiac lipomas are uncommon, usually asymptomatic benign primary tumors of the heart that may incidentally be discovered during computed tomography (CT) or magnetic resonance imaging (MRI). Although the finding of a low-attenuation mass with density similar to fat on CT is pathognomonic, the MRI appearances of fatty cardiac masses are variable depending on the sequences employed. The MRI findings of 4 patients with cardiac lipomas or lipomatous hypertrophy of the interatrial septum are presented. All patients had lesions with characteristic low-signal-intensity margins and high central signal intensity on "bright-blood" balanced gradient-echo cardiac MRI sequences with very low repetition and echo times. It is proposed that this appearance results from intravoxel phase cancellation effects occurring at the fat/tissue interface and is sufficiently characteristic to obviate the need for confirmatory CT.


Assuntos
Cardiomegalia/diagnóstico , Átrios do Coração/patologia , Neoplasias Cardíacas/diagnóstico , Septos Cardíacos/patologia , Lipoma/diagnóstico , Imageamento por Ressonância Magnética , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Aumento da Imagem , Miocárdio/patologia , Tomografia Computadorizada por Raios X
10.
J Vasc Surg ; 38(2): 313-8, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12891113

RESUMO

OBJECTIVE: To prevent iodinated contrast medium-induced nephrotoxicity, gadolinium has been used increasingly for magnetic resonance angiography (MRA) or conventional digital subtraction angiography (DSA) to visualize arterial anatomy in patients undergoing vascular surgery who are considered at high risk because of chronic renal insufficiency. We assessed the safety of gadolinium-based contrast medium as a substitute for iodinated contrast medium-enhanced examinations. We determined the incidence of gadolinium-induced nephrotoxicity in a clinical setting and searched for contributing risk factors. Patients and methods In a single-center retrospective study from December 1999 to January 2001, 218 inpatients underwent MRA and 42 inpatients underwent DSA, with gadolinium as the sole contrast agent. Patient comorbid conditions, indications for vascular imaging, contrast dose, urine output, baseline and post-procedure serum creatinine concentration (SCr), and outcome were recorded for all patients in whom gadolinium-induced renal failure developed. RESULTS: Of 260 patients who received gadolinium-based contrast agents, at a dose of 0.25 mmol/kg or more, 195 patients (75%) had pre-test baseline chronic renal insufficiency. In 7 of 195 patients (3.5%) acute renal failure developed after gadolinium-based contrast medium administration, for MRA (n = 153) in 3 patients (1.9%) and DSA (n = 42) in 4 patients (9.5%). Average baseline SCr in the 195 patients with chronic renal insufficiency was 38.2 +/- 1.6 mL/min/1.73 m(2), and in the 7 patients in whom acute renal failure developed, baseline SCr was 32.5 +/- 7.8 mL/min/1.73 m(2) (P =.33). Respective intravenous and intra-arterial gadolinium doses in these 7 patients ranged from 0.31 to 0.41 mmol/kg for MRA and 0.27 to 0.42 mmol/kg for DSA. Acute renal failure did not develop in any of 65 patients with normal baseline SCr. CONCLUSION: Despite reports of negligible nephrotoxicity, rarely gadolinium-based contrast agents can cause acute renal failure in patients with underlying chronic renal insufficiency. Estimation of creatinine clearance alone does not enable prediction of which patients are likely to have acute renal failure. Patients at high-risk should be identified, and prophylactic measures should be taken to reduce the risk for nephrotoxicity.


Assuntos
Injúria Renal Aguda/induzido quimicamente , Meios de Contraste/efeitos adversos , Gadolínio/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Angiografia/métodos , Comorbidade , Feminino , Humanos , Falência Renal Crônica/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Resultado do Tratamento
11.
Radiology ; 223(1): 270-4, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11930077

RESUMO

Comprehensive aortic magnetic resonance (MR) examinations currently include multiple nonenhanced and contrast material-enhanced sequences. The authors hypothesized that the nonenhanced true fast imaging with steady-state precession (FISP) portion alone of their comprehensive imaging protocol would be adequate to confidently confirm or exclude dissection or aneurysm of the aorta. In a retrospective review of 29 comprehensive thoracic aortic MR examinations, nonenhanced true FISP MR imaging alone was 100% accurate for determining the presence or absence of dissection or aneurysm.


Assuntos
Aneurisma da Aorta Torácica/patologia , Dissecção Aórtica/patologia , Angiografia por Ressonância Magnética/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo
12.
Radiology ; 227(1): 283-8, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12616011

RESUMO

In 15 healthy volunteers undergoing coronary magnetic resonance (MR) angiography, the breath-hold duration with and without preoxygenation was measured. The effect of preoxygenation on coronary artery imaging was also evaluated. A three-dimensional magnetization-prepared true fast imaging with steady-state precession sequence was employed for coronary MR angiography. All subjects showed an increase in comfortable breath-hold duration with preoxygenation. This extra imaging time allowed coronary artery imaging with increased spatial resolution.


Assuntos
Angiografia Coronária/métodos , Angiografia por Ressonância Magnética , Oxigênio/administração & dosagem , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Respiração , Fatores de Tempo
13.
Radiology ; 227(2): 585-92, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12663818

RESUMO

The majority of spinal magnetic resonance (MR) imaging has been performed with spin-echo sequences and spoiled gradient-echo sequences. Advances in gradient MR imaging performance now permit imaging with coherent steady-state sequences. In this study, the authors compare a three-dimensional true fast imaging with steady-state precession sequence with a three-dimensional spoiled gradient-recalled-echo sequence for MR evaluation of the cervical spine in the transverse plane. Initial experience indicates that the steady-state sequence is superior to spoiled gradient-recalled-echo sequences for MR evaluation of cervical spine anatomy and abnormalities.


Assuntos
Imageamento Tridimensional , Imageamento por Ressonância Magnética , Mielografia/métodos , Doenças da Medula Espinal/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Doenças da Medula Espinal/patologia , Fatores de Tempo
14.
J Vasc Interv Radiol ; 14(4): 441-9, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12682200

RESUMO

PURPOSE: To preoperatively assess the entire hepatic vasculature in living related liver donors with use of a combination of contrast material-enhanced magnetic resonance (MR) angiography and true fast imaging with steady-state precession (FISP). MATERIALS AND METHODS: Twenty-five living potential liver donors were examined preoperatively on a 1.5T Siemens Sonata system. Twenty-four underwent surgery and two had catheter angiography performed to delineate complex anatomy. Contiguous 5-mm-thick, sub-second true FISP images of the liver were initially obtained during breath-holding in axial and coronal planes (repetition time [TR]/echo time [TE], 3.2/1.6; flip angle, 70 degrees ). MR angiography was performed with use of a three-dimensional (3D) gradient-echo fast low-angle shot (FLASH) pulse sequence (TR/TE, 3.0/1.2; flip angle, 25 degrees ), with 40 mL of Gadolinium DTPA injected at a rate of 2 mL/sec. One precontrast and two postcontrast coronal 3D volumes were acquired, each in a 20-second breath-hold, and two subtracted 3D sets were calculated. Arterial anatomy was assessed with use of maximum-intensity projection, volume rendering, and multiplanar reformatting algorithms. Hepatic and portal venous anatomy was evaluated with use of the true FISP images and the venous phase of the MR angiogram. Visualization of hepatic arterial branches was noted. Visualization of portal vein branches was scored on a scale of 0-5. The presence of anatomic variants was noted. Vascular anatomy was confirmed at the time of surgery and at catheter angiography. RESULTS: Segmental branch vessels were visualized on MR angiography in the majority of cases. The segment four branch was identified in 96% patients. Variant arterial anatomy was seen in 50% of patients. MR angiography detected 10 of 11 arterial variants found at surgery and angiography. Visualization of portal vein branches was generally higher with true FISP compared to MR angiography. Twenty-four percent of patients had variant portal venous anatomy. Caudal hepatic veins were identified in 60% of patients, of which eight were significant (>5 mm). Hepatic and portal venous anatomy was accurately predicted by true FISP and MR angiography in all patients who went on to undergo surgery. CONCLUSION: Preoperative imaging with use of a combination of contrast-enhanced MR angiography and true FISP provides a comprehensive assessment of the entire hepatic vasculature in living liver donors.


Assuntos
Meios de Contraste , Transplante de Fígado , Fígado/irrigação sanguínea , Fígado/diagnóstico por imagem , Doadores Vivos , Angiografia por Ressonância Magnética , Cuidados Pré-Operatórios , Intensificação de Imagem Radiográfica , Adulto , Feminino , Artéria Hepática/anatomia & histologia , Artéria Hepática/diagnóstico por imagem , Artéria Hepática/cirurgia , Veias Hepáticas/anatomia & histologia , Veias Hepáticas/diagnóstico por imagem , Veias Hepáticas/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Veia Porta/diagnóstico por imagem , Veia Porta/cirurgia , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Resultado do Tratamento
15.
J Vasc Surg ; 37(1): 62-71, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12514579

RESUMO

OBJECTIVES: Standard lower extremity contrast-enhanced magnetic resonance angiography (LE-CEMRA) with single injection bolus-chase methods on the basis of a single pelvis timing run can be accurate for depicting most vascular occlusive lesions but may fall short of catheter-based angiography when imaging tibial and pedal vessels. Magnetic resonance angiography techniques with a second contrast timing bolus and separate acquisitions for the calves and the pelvis greatly improve reliability and reduce venous contamination to levels that may render conventional angiography obsolete. METHODS: From July to December 2001, 60 consecutive patients underwent LE-CEMRA of the calves with separate stepping-table acquisitions of the pelvis and thighs. Forty-five (75%) had complete or partial angiographic correlation during an endoluminal intervention or operative completion study. Lower extremity vessels were divided into anatomic segments (aortoiliac, femoropopliteal, tibial-pedal) for review. Three blinded observers assessed magnetic resonance source partitions, maximum-intensity projections, and volume-rendered images. Disease per segment was graded from insignificant (<20%) to occluded (100%) in 10% increments. Segments were also scored for venous contamination (scale, 0 to 3) and diagnostic quality (scale, 1 to 5). Digital subtraction angiograms were assessed similarly but separately. RESULTS: The combination dual-timing/dual-injection technique had an overall sensitivity, specificity, and accuracy of 99%, 97%, and 98%. Venous contamination and artifact were virtually eliminated with combined technique LE-CEMRA. Diagnostic quality of calf and foot vessels was significantly superior to conventional bolus-chase magnetic resonance techniques (P <.01). CONCLUSION: Hybrid dual-acquisition LE-CEMRA allows complete timing specification that consistently produces high-quality, artifact-free images of the calf and pedal vessels. These techniques may be accurate enough to replace conventional digital subtraction angiogram for evaluation of lower extremity vascular occlusive disease.


Assuntos
Meios de Contraste/administração & dosagem , Perna (Membro)/irrigação sanguínea , Angiografia por Ressonância Magnética/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade
16.
Radiology ; 224(3): 896-904, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12202730

RESUMO

The purpose of the study was to implement a three-dimensional (3D) magnetic resonance (MR) angiographic technique with acquisition times on the order of 800 msec with use of a spoiled gradient-echo pulse sequence (repetition time, 1.60 msec; echo time, 0.65 msec) and bolus intravenous injection of contrast material doses as small as 6 mL. High-spatial-resolution conventional MR angiography performed with 30 mL of gadopentetate dimeglumine was the reference standard. As implemented, subsecond 3D MR angiography allowed temporal sampling that was rapid enough to depict short-lived processes, as illustrated in patients with shunts and dissections. With small contrast material doses and subsecond frame rates, it is also possible to measure pulmonary arteriovenous circulation times with this 3D MR angiographic technique.


Assuntos
Angiografia por Ressonância Magnética/métodos , Tórax/anatomia & histologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Doenças da Aorta/diagnóstico , Meios de Contraste/administração & dosagem , Feminino , Gadolínio DTPA/administração & dosagem , Cardiopatias/diagnóstico , Humanos , Pneumopatias/diagnóstico , Masculino , Pessoa de Meia-Idade , Circulação Pulmonar
17.
J Vasc Interv Radiol ; 13(11): 1149-53, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12427815

RESUMO

PURPOSE: To determine if magnetic resonance (MR) imaging significantly alters the diagnostic thinking and treatment plans of interventional radiologists during the evaluation of women for uterine fibroid embolization (UFE) for presumed uterine fibroids. MATERIALS AND METHODS: At a single institution, interventional radiologists prospectively completed questionnaires (n = 60) before and after MR imaging was performed in their evaluation of women presenting for potential UFE. The questionnaires asked these physicians the probability (0%-100%) of their most likely diagnosis before MR imaging and after receiving the MR imaging information. They were also asked their anticipated and final treatment plans. Diagnostic confidence gains and the proportion of patients with changed initial diagnoses or anticipated management were calculated. The Wilcoxon signed-rank test was used to assess gains in diagnostic confidence. RESULTS: MR imaging caused a mean gain in diagnostic confidence of 22% (P <.0001). MR imaging changed initial diagnoses in 11 patients (18%). Immediate clinical management changed in 13 patients (22%). UFE was not performed in 11 of 57 women (19%) who were anticipated before MR imaging to receive UFE. CONCLUSIONS: MR imaging significantly alters the diagnoses and treatment plans of interventional radiologists evaluating women with presumed symptomatic fibroids. MR imaging should be considered in all patients before UFE.


Assuntos
Leiomioma/patologia , Leiomioma/terapia , Pelve/patologia , Neoplasias Uterinas/patologia , Neoplasias Uterinas/terapia , Adulto , Embolização Terapêutica , Feminino , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Estudos Prospectivos , Inquéritos e Questionários
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA