RESUMEN
Fluid-attenuated inversion-recovery (FLAIR) imaging has shown to be a valuable imaging modality in the assessment of intra-axial brain tumors; however, no data are available about the role of this technique in the clinically important postoperative stage. The purpose of this study was to evaluate the diagnostic potential of FLAIR MR imaging in residual tumor after surgical resection of cerebral gliomas. Fifteen patients with residual cerebral gliomas were examined within the first 18 days after partial surgical resection of cerebral gliomas. The imaging protocol included T1-weighted spin echo, T2- and proton-density-weighted fast spin echo, and FLAIR imaging with identical slice parameters. T1 and FLAIR were repeated after contrast media application. Detection and delineation of residual tumor were the primary parameters of the image analysis. Additionally, the influence of image artifacts on the image interpretation was assessed. On FLAIR images residual signal abnormalities at the border of the resection cavities were observed in all patients, whereas T2- and T1-weighted images present residual abnormalities in 13 of 15 and 10 of 15 patients, respectively. The FLAIR imaging was found to be superior to conventional imaging sequences in the delineation of these changes and comparable to contrast enhanced T1-weighted imaging in the delineation of residual enhancing lesions. Because of protein cell components and blood byproducts within the resection cavity, FLAIR imaging was unable to suppress the cerebrospinal fluid (CSF) in 4 patients. After the decomposition of proteins and blood, CSF could again be completely suppressed and residual or recurrent tumors were clearly identified. Our preliminary study has shown that FLAIR may be a valuable diagnostic modality in the early postoperative MR imaging after resection of cerebral gliomas due to its better delineation of residual pathologic signal at the border of the resection cavity. It should therefore be integrated into the early and/or intraoperative MR imaging protocol.
Asunto(s)
Neoplasias Encefálicas/patología , Neoplasias Encefálicas/cirugía , Glioma/patología , Glioma/cirugía , Imagen por Resonancia Magnética , Adolescente , Adulto , Anciano , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Neoplasia Residual , Periodo PosoperatorioRESUMEN
It was the aim of this methodology-oriented clinical pilot study to compare the potential of dynamic MRI and 2-[18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) for the detection and characterization of breast cancer. Fourteen women with suspicious breast lesions were examined. The MRI data were acquired with a turbo fast low-angle shot sequence and analyzed using a pharmacokinetic model. Emission data were detected in the sensitive 3D modus, iteratively reconstructed, and superimposed onto corresponding transmission images. In the 14 patients, 13 breast masses with a suspicious contrast enhancement and FDG uptake were detected. For these lesions, no statistically significant correlation between evaluated MR and PET parameters was found. Of the 9 histologically confirmed carcinomas, 8 were correctly characterized with MRI and PET. Two inflammatory lesions were concordantly classified as cancer. Moreover, dynamic MRI yielded another false-positive finding. In 6 patients, PET detected occult lymph node and/or distant metastases. Although both functional imaging techniques provide independent tissue information, the results concerning the diagnosis of primary breast lesions were almost identical. An advantage of PET, however, is its ability to localize lymph node involvement and distant metastases as an integral part of the examination.
Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/patología , Fluorodesoxiglucosa F18 , Imagen por Resonancia Magnética , Radiofármacos , Tomografía Computarizada de Emisión , Adulto , Anciano , Femenino , Humanos , Persona de Mediana Edad , Estudios ProspectivosAsunto(s)
Ligamentos/lesiones , Angiografía por Resonancia Magnética , Imagen por Resonancia Magnética , Fracturas de la Columna Vertebral/diagnóstico , Traumatismos Vertebrales/diagnóstico , Accidentes de Tránsito , Adulto , Fenómenos Biomecánicos , Vértebras Cervicales/lesiones , Niño , Humanos , Vértebras Lumbares/lesiones , Imagen por Resonancia Magnética/métodos , Fracturas de la Columna Vertebral/clasificación , Traumatismos Vertebrales/clasificación , Traumatismos Vertebrales/fisiopatología , Vértebras Torácicas/lesionesRESUMEN
The aim of our study was to investigate the quantitative microcirculation parameters amplitude A (hypothetical intravascular volume) and exchange rate constant k(21) (hypothetical vascular permeability) by contrast-enhanced dynamic magnetic resonance imaging (dMRI) as markers of angiogenesis in multiple myeloma (MM). Therefore lumbar spine and spina iliaca superior posterior of 16 normal controls and 41 patients with active MM were assessed using a dMRI protocol with a pump controlled bolus infusion of Gadolinium-DTPA. Pharmacokinetic parameters, amplitude A and exchange rate constant k(21) were calculated according to a 2-compartment model. Color-coded parameter images were generated from pharmacokinetic data analysis and superimposed onto the conventional MR images. Amplitude A and k(21) parameters were significantly increased in patients with MM compared with controls (p = 0.001; median A(ctr), 0.2 [range, 0.09-0.4]; median A(MM), 0.93 [range, 0.2-2.2]; median k(21ctr), 0.09 min(-1) [range, 0.03-0.9]; median k(21MM), 4.58 [range, 0.22-23.8]). Within the group of MM patients the pattern of color-coded parameter images were found to be either of "diffuse" (n = 13, 31%) or "focal" (n = 28, 69%) type of distribution of microcirculation. Comparison of amplitude A in patients with "focal" vs. "diffuse" pattern of the pharmacokinetic maps revealed a significant increase in the median of amplitude A in the "focal" group. Amplitude A values allowed a classification of patients according to severe osteolytic bone involvement (p = 0.023) with the best cutoff value of 0.7 for amplitude A. Downmodulation of amplitude A was observed in a MM patient treated with standard VAD chemotherapy. Our data demonstrate that dMRI is a novel imaging technique for the detection and monitoring of MM bone lesions. It provides independent evidence for angiogenesis in MM.
Asunto(s)
Médula Ósea/irrigación sanguínea , Imagen por Resonancia Magnética/métodos , Microcirculación , Mieloma Múltiple/patología , Adulto , Anciano , Médula Ósea/patología , Estudios de Casos y Controles , Medios de Contraste/farmacología , Femenino , Gadolinio DTPA/farmacocinética , Humanos , Inmunohistoquímica , Región Lumbosacra/patología , Masculino , Persona de Mediana Edad , Programas Informáticos , Factores de TiempoRESUMEN
PURPOSE/OBJECTIVE: With the increasing number of patients successfully treated with stereotactic radiosurgery for brain metastases, decision making after therapy based on follow-up imaging findings becomes more and more important. Magnetic resonance imaging (MRI) is the most sensitive means for follow-up studies. The objective of this study was to investigate the treatment outcome of our radiosurgery program and to describe the response of brain metastases to contrast-enhanced MRI after linear accelerator (linac) stereotactic radiosurgery and identify factors to distinguish among local control and local failure. METHODS AND MATERIALS: Using serial MRI, we followed the course of 87 brain metastases in 48 consecutive patients treated between September 1996 and November 1997 with linac-based radiosurgery with 15-MV photons. Treatment planning was performed on an MR data cube. For spherical metastases, radiosurgery was delivered using a 9 noncoplanar arc technique with circular-shaped collimators. For irregularly shaped targets, radiosurgery was delivered using a manually driven multi-leaf collimator with a leaf width of 1.5 mm projected to the isocenter. Median radiosurgery dose was 20 Gy prescribed to the 80% isodose. Together with whole brain radiotherapy (20 x 2 Gy, 5/w), a median radiosurgical dose of 15 Gy was delivered. Median follow-up was 8 (range 2--36) months. Factors influencing local control and survival rates were analyzed with respect to MRI response, and Kaplan-Meier curves were calculated. RESULTS: Actuarial local tumor control was 91% at one and two years. Patient survival at one and two years was 30% and 18%. Median survival was 9 months. During follow-up in 70 (81%) of the 87 treated metastases, the contrast-enhancing volumes on T1W images were stable or disappeared partly or completely. A transient enlargement of contrast-enhancing volumes was observed in 11 (12%) of the 87 lesions treated, while a progressive enlargement due to local treatment failure was observed in 6 (7%) of the 87 treated metastases. Younger age, early contrast onset after radiosurgery, and previous chemotherapy were associated with this transient enlargement of contrast-enhancing lesion volume. CONCLUSIONS: Linac-based radiosurgery is an effective, noninvasive, and safe treatment option for patients with brain metastases. A marked enlargement of the contrast-enhancing volume on T(1)-weighted MR images after radiosurgery is a sensitive predictor for, but not equivalent with, local failure. In as many as two-thirds of the cases with contrast enlargement in MRI follow-up, the contrast enlargement is transient with no need for further treatment. While some MRI findings are more likely if transient enlargement is present, a clear decision cannot be made based on MRI, and ultimately the clinical status dictates further action.
Asunto(s)
Neoplasias Encefálicas/patología , Neoplasias Encefálicas/cirugía , Medios de Contraste , Imagen por Resonancia Magnética , Radiocirugia , Análisis de Varianza , Neoplasias Encefálicas/secundario , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Resultado del TratamientoAsunto(s)
Ligamentos Articulares/lesiones , Imagen por Resonancia Magnética , Traumatismos Vertebrales/diagnóstico , Humanos , Luxaciones Articulares/diagnóstico , Inestabilidad de la Articulación/diagnóstico , Ligamentos Articulares/patología , Fracturas de la Columna Vertebral/diagnóstico , Traumatismos Vertebrales/clasificación , Columna Vertebral/patologíaRESUMEN
Magnetic resonance imaging has been shown to be the most sensitive imaging modality in the assessment of gliomatosis cerebri. Recent studies have shown that fluid-attenuated inversion-recovery (FLAIR) is a valuable MR sequence in the delineation of cerebral pathologies including intra-axial tumors. However, no data are available about the role of this novel technique in the assessment of gliomatosis lesions. The purpose of this study was therefore to evaluate the diagnostic potential of FLAIR MR imaging in patients with suspected gliomatosis cerebri. Seven patients suspected of having lesions of gliomatosis cerebri were examined by T1-weighted spin echo (SE), T2-weighted fast spin echo (FSE), and FLAIR MR imaging with identical slice parameters. T1 and FLAIR were repeated after contrast media administration. Delineation and extent of gliomatosis were the primary parameters of the image analysis. The FLAIR imaging clearly delineated the extent of gliomatosis lesions in all patients. Due to the suppression of cerebrospinal fluid, the delineation was superior to conventional T2-weighted FSE images. Especially the detection and delineation of cortical spread and the infiltration of the corpus callosum was best seen on FLAIR images. The FLAIR MR imaging is a valuable diagnostic modality in the assessment of patients with gliomatosis cerebri. Due to its better delineation of tumor spread, it was found to be the imaging method of choice and should therefore be integrated into the MR imaging protocol of these patients.
Asunto(s)
Neoplasias Encefálicas/diagnóstico , Encéfalo/patología , Imagen Eco-Planar/métodos , Neoplasias Neuroepiteliales/diagnóstico , Adulto , Anciano , Biopsia , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los ResultadosRESUMEN
Close inspection of MR images in all stages of SCI can reveal alterations which are important for our understanding of the changes which occur in SCI and may be crucial for planning surgical intervention. Importantly also, these observations may assist in the evaluation of novel therapies in SCI, such as cellular transplantation. It is hopeful that MR strategies which are currently in routine use in the brain, such as diffusion weighted imaging, perfusion studies, spectroscopy, and magnetization transfer can be adopted for use in the spine [8]. Because of the small size of the cord, the magnetic susceptibility problems caused by surrounding air and bone, and nearby vascular and CSF flow/pulsations, these techniques are currently very difficult to employ in the cord. They will however evolve over time and give us greater insights into the in-vivo status of the injured cord.
Asunto(s)
Imagen por Resonancia Magnética , Traumatismos de la Médula Espinal/diagnóstico , Médula Espinal/patología , Humanos , Planificación de Atención al Paciente , Pronóstico , Traumatismos de la Médula Espinal/patología , Traumatismos de la Médula Espinal/cirugíaRESUMEN
Diffusion weighted magnetic resonance imaging (DWI) represents a recent development that extends imaging from the depiction of the neuroanatomy into the field of functional and physiologic processes. DWI measures a fundamentally different physiologic parameter than conventional MRI. Image contrast is related to differences in the microscopic motion (diffusion) of water molecules within brain tissue rather than a change in total tissue water. Consequently, DWI can reveal pathology where conventional T1- and T2-weighted MR images are negative. DWI has clinically proven its value in the assessment of acute cerebral stroke and trauma by showing cerebral injury early due to ist ability to discriminate between lesions with cytotoxic edema (decreased diffusion) from lesions with vasogenic edema (increased diffusion). Full tensor DWI allows to calculate a variety of functional maps, the most widely used maps include maps of apparent diffusion coefficients and isotropic diffusion. In addition maps of anisotropic diffusion can be calculated which are believed to give information about the integrity and location of fiber tracts. This functional-anatomical information will most probably play an increasingly important role in the early detection of primary and secondary tissue injury from various reasons and could guide and validate current and future neuroprotective treatments.
Asunto(s)
Lesiones Encefálicas/diagnóstico , Isquemia Encefálica/diagnóstico , Infarto Cerebral/diagnóstico , Aumento de la Imagen , Imagen por Resonancia Magnética , Traumatismos de la Médula Espinal/diagnóstico , Isquemia de la Médula Espinal/diagnóstico , Animales , Artefactos , Barrera Hematoencefálica/fisiología , Encéfalo/patología , Edema Encefálico/diagnóstico , Diagnóstico Diferencial , Difusión , Humanos , Sensibilidad y Especificidad , Médula Espinal/patologíaRESUMEN
The improvement of preclinical emergency medicine has increased the long-term survival of patients which sustained severe injuries of the spinal cord. However, the incidence of late complications has been increased due to the long-term survival. With the increasing use of magnetic resonance imaging (MRI) in this patient group the diagnosis of typical late complications of the spinal cord has improved. In this article we suggest the following terms to describe late complications of the spinal cord: syrinx, atrophy, cyst, malacia, disruption, and thethering.
Asunto(s)
Imagen por Resonancia Magnética , Traumatismos Vertebrales/diagnóstico , Atrofia , Quistes del Sistema Nervioso Central/diagnóstico , Humanos , Defectos del Tubo Neural/diagnóstico , Médula Espinal/patología , Traumatismos Vertebrales/complicaciones , Siringomielia/diagnósticoRESUMEN
AIM OF THE STUDY: Investigation of the quantitative microcirculation parameters amplitude A and exchange rate constant k21 determined by contrast-enhanced dynamic magnetic resonance imaging (d-MRI) in multiple myeloma (MM). METHODS: d-MRT of lumbar spine and right spina iliaca superior posterior of 16 controls (ctr) and 35 patients with active MM. Generation of colour-coded images of microcirculation parameters superimposed onto static MRI images. RESULTS: Amplitude A and k21 parameters were significantly increased in patients with MM and down modulated by therapy in 7 of 8 MM cases in a follow-up investigation [p < 0.01; median Actr = 0.2 (0.09-0.4); median AMM = 0.93 (0.2-1.52); median k21ctr = 0.09 min-1 (0.03-0.9); median k21MM = 4.57 min-1 (0.21-23.8)]. Thirteen patients revealed a "diffuse" and 22 a "focal" pattern of distribution of microcirculation parameters. Bone marrow biopsies in 8 cases revealed an correlation between bone marrow plasma cell infiltration and increased microcirculation parameters. CONCLUSION: Identification of microcirculation changes by d-MRI is a novel imaging technique for the detection and monitoring of MM bone lesions.
Asunto(s)
Monitoreo de Drogas , Imagen por Resonancia Magnética , Mieloma Múltiple/diagnóstico , Antineoplásicos Alquilantes/administración & dosificación , Antineoplásicos Hormonales/administración & dosificación , Antineoplásicos Fitogénicos/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Médula Ósea/irrigación sanguínea , Médula Ósea/metabolismo , Médula Ósea/patología , Ciclofosfamida/administración & dosificación , Dexametasona/administración & dosificación , Monitoreo de Drogas/métodos , Etopósido/administración & dosificación , Humanos , Ilion/irrigación sanguínea , Ilion/metabolismo , Ilion/patología , Inmunohistoquímica , Vértebras Lumbares/irrigación sanguínea , Vértebras Lumbares/metabolismo , Vértebras Lumbares/patología , Imagen por Resonancia Magnética/instrumentación , Imagen por Resonancia Magnética/métodos , Microcirculación/metabolismo , Microcirculación/patología , Mieloma Múltiple/tratamiento farmacológico , Mieloma Múltiple/metabolismo , Talidomida/administración & dosificaciónRESUMEN
The purpose of this study was to assess the diagnostic potential of a new dark fluid sequence, high intensity reduction (HIRE) in the diagnostic workup of patients with cerebral gliomas. The HIRE sequence utilizes a very long T(2) value of the cerebrospinal fluid (CSF) to suppress its high signal contribution in T(2)-weighted imaging by a image subtraction technique. Fifteen patients with histologically confirmed cerebral gliomas were examined with T(2)-weighted fast spin-echo (FSE), T(1)-weighted SE, fast fluid-attenuated inversion recovery (FLAIR), and HIRE imaging using identical scan parameters. In patients with enhancing lesions, fast FLAIR and HIRE were added to the contrast-enhanced T(1)-weighted SE images. Images were analyzed in a qualitative and quantitative evaluation. In the qualitative analysis, lesion detection, lesion delineation, and differentiation between enhancing and non-enhancing tumor tissue were assessed in a two-reader study. For the quantitative analysis, lesion-to-background and lesion-to-CSF contrast and contrast-to-noise ratios were determined in a region of interest analysis. HIRE achieved a significant reduction of the CSF signal without losing the high gray-to-white matter contrast of T(2)-weighted sequences. In the quantitative analysis, the contrast ratios of the HIRE images were lower compared with the FLAIR images due to a relatively high background and CSF signal. After administration of contrast media, HIRE images presented a significant signal increase in enhancing lesions, which subsequently increased the contrast and contrast-to-noise ratios. In the qualitative analysis, both readers found all tumors clearly delineated on HIRE imaging. Compared with T(2)-weighted FSE, the tumor delineation with HIRE was better in nine patients, equal in four patients, and less in one patient. Compared with the FLAIR images, HIRE was rated superior in three patients, equal in nine patients, and inferior in another three patients. Delineation of the enhancing tumor parts was possible with HIRE in all patients. HIRE images had significantly fewer image artifacts than FLAIR images due to reduced inflow effects. The T(2)-based HIRE sequence presented is an alternative to the T(1)-based FLAIR sequence, with the advantage of better gray-to-white matter contrast and shorter measurement time. Due to the subtraction technique, signal intensities from tissues with relaxation times in the range T(2 WM) < < T(2) < T(2 CSF) are also gradually affected, corresponding to their T(2) values. With respect to this unwanted effect, an improvement in HIRE imaging will be possible by using a self-weighted subtraction algorithm. In a forthcoming study this concept will first be tested on appropriate phantom fluids.
Asunto(s)
Neoplasias Encefálicas/diagnóstico , Encéfalo/patología , Glioma/diagnóstico , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Adulto , Artefactos , Medios de Contraste , Femenino , Gadolinio DTPA , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Técnica de SustracciónRESUMEN
Angiogenesis is a factor of spread and metastatization. This fact has been established for many malignancies, but the data concerning cervical cancer are rather conflicting. In a study including 42 patients affected by cervical cancer stages IB to IVA, the authors assess the mean capillary density and the correlations between this parameter and the other anatomoclinical parameters: the VEGF expression, tumoral oxygenation and the data obtained from dynamic MRI. The histologic assessment of the capillary density and the data obtained by dynamic MRI enable us at the same time to quantify the tumoral angiogenesis and establish the prognosis. The two methods could be used routinely as markers of prognosis. VGEF surely plays a role in angiogenesis linked with cervical cancer growth, but its regulation is not definitively clear at the moment. The impact of tumoral oxygenation (whose place as a prognostic marker is clearly established) on tumoral angiogenesis and vessels' permeability as well as its control is currently not clearly established. Further studies on larger populations are necessary.
Asunto(s)
Neovascularización Patológica , Neoplasias del Cuello Uterino/irrigación sanguínea , Adulto , Anciano , Anciano de 80 o más Años , Capilares/patología , Factores de Crecimiento Endotelial/análisis , Factor VIII/análisis , Femenino , Humanos , Linfocinas/análisis , Imagen por Resonancia Magnética , Persona de Mediana Edad , Oximetría , Consumo de Oxígeno , Pronóstico , Neoplasias del Cuello Uterino/metabolismo , Neoplasias del Cuello Uterino/patología , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial VascularRESUMEN
BACKGROUND: FLAIR MR imaging has shown to be a valuable imaging modality in pathologic lesions of the brain including intra-axial brain tumors. The aim of the study was to assess the value of a FLAIR technique in the planning process of stereotactic radiotherapy in patients with cerebral gliomas and metastases. PATIENTS AND METHODS: Thirty-five patients with cerebral gliomas and 12 patients with a total of 39 cerebral metastases were examined by T2/PD-weighted fast spin-echo, fast FLAIR prior and after contrast and contrast enhanced T1-weighted spin-echo using identical slice parameters. The images were evaluated by using quantitative and qualitative criteria. Quantitative criteria were tumor-to-background and tumor-to-cerebrospinal fluid contrast and contrast-to-noise. The qualitative evaluation was performed as a multireader analysis concerning lesion detection, lesion delineation and image artifacts. RESULTS: In the qualitative evaluation (Table 3 and 6), all readers found the fast FLAIR images to be superior to fast spin-echo in the exact delineation of cerebral tumors (p < 0.001) and the delineation of enhancing and non enhancing tumor parts. Fast FLAIR was superior in the delineation of cortically located and small lesions but was limited in lesions adjacent to the ventricles. Fast FLAIR provided a significantly better tumor-to-CSF contrast and tumor-to-CSF contrast-to-noise (p < 0.001) (Tables 1, 2a, 2b, 4, 5). The tumor-to-background contrast and tumor-to-background contrast-to-noise of the fast FLAIR images were lower than that of T2-weighted spin-echo images but were significantly increased after the application of contrast media. FLAIR images had more image artifacts, but the image interpretation was not influenced. CONCLUSIONS: FLAIR MR imaging was found to be a valuable sequence in the planning protocol of stereotactic radiotherapy. The concurrent presentation of enhancing and non enhancing tumor tissue on contrast enhanced fast FLAIR imaging enables to use a single imaging sequence in the treatment protocol. This enables to load a reduced image amount into the radiotherapy planning software, is therefore time saving and reduces potential errors.
Asunto(s)
Neoplasias Encefálicas/cirugía , Medios de Contraste , Glioma/cirugía , Imagen por Resonancia Magnética/métodos , Radiocirugia/métodos , Planificación de la Radioterapia Asistida por Computador/métodos , Adolescente , Adulto , Anciano , Encéfalo/patología , Encéfalo/cirugía , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/secundario , Femenino , Glioma/diagnóstico , Humanos , Imagen por Resonancia Magnética/instrumentación , Imagen por Resonancia Magnética/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Radiocirugia/estadística & datos numéricos , Planificación de la Radioterapia Asistida por Computador/estadística & datos numéricosRESUMEN
This article reviews the experience available to date on microcirculation assessment in cancer of the cervix including correlation studies of magnetic resonance (MR) microcirculatory parameters with histo-morphometric predictors and direct correlation with patient outcome. The data suggest that MR microcirculation parameters do not always correlate with histo-morphometric parameters, while there is evidence that MR parameters predict patients' treatment outcome. These observations raise the issue that perhaps the histo-morphometric parameters, accepted gold standards for tumor angiogenesis and prognostic factors, reflect anatomical information at a "static" single time point and may not always provide sufficient information on the "dynamic" microcirculation function of the tumor. MR microcirculation assessment reflects both anatomical and functional information and may provide this additional information on the "dynamic" angiogenic and metabolic status of a tumor. Therefore, assessment of tumor microcirculation may augment the individual risk profile in cervical cancer patients and has the potential to impact on therapy selection and treatment outcome.
Asunto(s)
Medios de Contraste , Gadolinio , Imagen por Resonancia Magnética/métodos , Microcirculación/patología , Neovascularización Patológica/patología , Neoplasias del Cuello Uterino/irrigación sanguínea , Neoplasias del Cuello Uterino/patología , Medios de Contraste/farmacocinética , Femenino , Gadolinio/farmacocinética , Humanos , Aumento de la Imagen/métodos , Procesamiento de Imagen Asistido por Computador , Recurrencia Local de Neoplasia , Valor Predictivo de las Pruebas , Pronóstico , Resultado del Tratamiento , Neoplasias del Cuello Uterino/metabolismoRESUMEN
Magnetic resonance imaging (MRI) is a noninvasive technique that complements computed tomography (CT), conventional X-ray, and bone marrow biopsies by sampling a large volume of musculoskeletal bone and providing information that aids the diagnosis, staging, and follow-up of various lesions. Although less sensitive to the mineral components of bones, the MRI appearance of physiologic bone marrow is mainly a reflection of the relative amounts of red marrow, yellow marrow, and trabecular bone. Therefore, use of T1-and T2-weighted MR sequences with or without fat suppression currently remains the most common approach to musculoskeletal bone lesion imaging. An additional imaging strategy to characterize various bone lesions is the application of contrast-enhanced dynamic MRI. This article examines semiquantitative and quantitative dynamic imaging, evaluation, and postprocessing techniques in various benign and malignant musculoskeletal lesions. Practical guidelines for performing a dynamic contrast-enhanced MR examination are proposed.
Asunto(s)
Neoplasias de la Médula Ósea/irrigación sanguínea , Medios de Contraste , Gadolinio DTPA , Imagen por Resonancia Magnética/métodos , Neovascularización Patológica/patología , Neoplasias de la Médula Ósea/patología , Medios de Contraste/farmacocinética , Gadolinio DTPA/farmacocinética , Humanos , Aumento de la Imagen/métodos , Procesamiento de Imagen Asistido por Computador , Osteomielitis/patologíaRESUMEN
To detect a renal artery stenosis and assess its hemodynamic and functional significance in five breath holds. In a single MR exam, T1 weighted FLASH and T2 weighted fast spin echo techniques are used to assess renal morphology, multiphase 3D gadolinium (Gd) MRA to evaluate the renal arteries, and a segmented EPI cine phase-contrast technique to measure renal artery blood flow. A standardized image analysis is performed to assess kidney size, corticomedullar differentiation (CMD), parenchymal enhancement, the degree of renal artery stenosis, abnormalities in blood flow pattern, and any associated abdominal vascular disease. Multiphase 3D-Gd-MRA accurately assesses atherosclerotic renal artery disease particularly in the presence of an associated aortic aneurysm. Delayed parenchymal enhancement, loss of CMD, and decrease in kidney size can be detected. In combination with decreased systolic velocity components, the diagnosis of a hemodynamically and functionally significant stenosis can be made. High-resolution single-phase 3D-Gd-MRA is preferable for evaluation of fibromuscular dysplasia or hypoplastic vessels. The combination of different breath hold techniques in a single, standardized MR exam allows to detect the hemodynamic and functional significance of a renal artery stenosis.
Asunto(s)
Medios de Contraste , Gadolinio , Angiografía por Resonancia Magnética/métodos , Obstrucción de la Arteria Renal/diagnóstico , Anciano , Hemodinámica , Humanos , Aumento de la Imagen/métodos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Obstrucción de la Arteria Renal/patología , Obstrucción de la Arteria Renal/fisiopatologíaRESUMEN
OBJECTIVE: To evaluate multiphasic 3D gadolinium-enhanced magnetic resonance angiography (3D-Gd-MRA) for detection of vascular pathology at multiple levels of the aorta and iliac arteries. METHODS: In 18 patients with abdominal aortic aneurysm (n = 13), dissection (n = 3), or both (n = 2), multiphase 3D-Gd-MRA was performed acquiring five consecutive (6.8 seconds) 3D data sets in a single breath-hold. In each of the five time-resolved phases, vessel visibility of the abdominal aortic branches and iliac arteries was assessed. The extent of vessel involvement by the aneurysm or dissection seen on multiphase 3D-Gd-MRA was compared with standard imaging and surgical findings. Digital subtraction angiography was available for comparison in 4 cases, CT angiography in 10 cases. RESULTS: Due to the delayed filling of the aortic aneurysm, the proximal aortic branches and the aneurysm neck demonstrated an inversely related enhancement compared with the distal abdominal and iliac vessels (P < 0.001). Review of all five phases of multiphase 3D-Gd-MRA allowed optimal visualization of each vessel segment without any artifacts due to parenchymal or venous overlay. In dissections, review of three phases was required (P < 0.001) for diagnostic evaluation of the true and false lumens. Substantially more vessel involvement was detected on multiphase 3D-Gd-MRA; this was surgically confirmed in 10 of 11 cases and affected therapy management in 11 of 18 cases. CONCLUSIONS: Multiphase 3D-Gd-MRA is a convenient, robust, and safe technique for presurgical anatomic mapping of complex aortic aneurysms and dissections.
Asunto(s)
Aneurisma de la Aorta Abdominal/patología , Angiografía por Resonancia Magnética/métodos , Disección Aórtica/patología , Medios de Contraste/administración & dosificación , Gadolinio DTPA/administración & dosificación , Humanos , Arteria Ilíaca , Intensificación de Imagen RadiográficaRESUMEN
PURPOSE: To investigate the value of multiphase breath-hold 3D gadolinium (Gd)-enhanced MR angiography (MRA) for lesion detection and characterization of focal liver lesions. MATERIALS AND METHODS: Breath-hold 3D Gd-enhanced MRA was performed in 25 patients with benign and malignant hepatic lesions on a 1.5-T MR system using an ultrafast 3D spoiled gradient echo sequence (TR/TE =5/2 ms, FOV=300-450 mm, matrix=256x168, voxel volume=1.8x2.3 x2.5 mm, 64 partitions, central k-space reordering; acquisition time=27 s). Three measurements were done in the arterial, portal venous, and late venous phase. RESULTS: The analysis of the spatial and temporal evolution of contrast enhancement of the 3D-MRA improved significantly (P<0.01) lesion detection and characterization if compared with T1 precontrast, T2-weighted, and T1 postcontrast images. CONCLUSION: Multiphase breath-hold 3D Gd-enhanced MRA imaging is a robust new technique to significantly improve morphological detection of benign and malignant lesions during the early arterial phase and further improves functional characterization of liver lesions by a combination of an arterial, a portal venous, and a late venous phase. Schlüssselwörter Multiphasisch. MR-Angiographie. Leberläsionen