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In the current study, we assessed changes in interstitial fluid dynamics resulting after whole-brain radiotherapy using the diffusion-weighted image analysis along the perivascular space (DWI-ALPS) method, which is a simplified variation of the diffusion tensor image ALPS (DTI-ALPS) method using diffusion-weighted imaging (DWI) with orthogonal motion-probing gradients (MPGs). This retrospective study included 47 image sets from 22 patients who underwent whole-brain radiotherapy for brain tumors. The data for the normal control group comprised 105 image sets from 105 participants with no pathological changes. DWI was performed with the three MPGs applied in an orthogonal direction to the imaging plane, and apparent diffusion coefficient images for the x-, y-, and z-axes were retrospectively generated. The ALPS index was calculated to quantify interstitial fluid dynamics. The independent t-test was used to compare the ALPS index between normal controls and patients who underwent whole-brain radiotherapy. Patients were compared in all age groups and individual age groups (20-39, 40-59, and 60-84 years). We also examined the correlation between biologically equivalent doses (BEDs) and the ALPS index, as well as the correlation between white matter hyperintensity and the ALPS index. In the comparison of all age groups, the ALPS index was significantly lower (p < 0.001) in the postradiation group (1.32 ± 0.16) than in the control group (1.44 ± 0.17), suggesting that interstitial fluid dynamics were altered in patients following whole-brain radiotherapy. Significant age group differences were found (40-59 years: p < 0.01; 60-84 years: p < 0.001), along with a weak negative correlation between BEDs (r = -0.19) and significant correlations between white matter hyperintensity and the ALPS index (r = -0.46 for periventricular white matter, r = -0.38 for deep white matter). It was concluded that the ALPS method using DWI with orthogonal MPGs suggest alteration in interstitial fluid dynamics in patients after whole-brain radiotherapy. Further systematic prospective studies are required to investigate their association with cognitive symptoms.
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BACKGROUND: Emergency rescue lung resection is rarely performed to treat congenital lung cysts (CLCs) in neonates. Many reports have described fetal CLC treatment; however, prenatal predictors for postnatal respiratory failure have not been characterized. We hypothesized that fetal imaging findings are useful predictors of emergency surgery. METHODS: We retrospectively studied patients with CLC who underwent lung surgery during the neonatal period in our hospital between January 2001 and December 2015. The demographic data, fetal imaging findings, and intra- and postoperative courses of patients who underwent emergency surgery (Em group) were compared with those of patients who received elective surgery, i.e., non-emergency surgery (Ne group). RESULTS: The Em group and Ne group included 7 and 11 patients, respectively. No significant difference was noted in gestational age, time at prenatal diagnosis, birth weight, and body weight at surgery. The volumes of contralateral lung per thoracic volume were significantly smaller in the Em group than in the Ne group (p = 0.0188). Mediastinal compression was more common in the Em group (7/7) than in the Ne group (4/11) (p = 0.0128). CONCLUSIONS: This is the report describing neonatal emergency lobectomy in patients with CLC evaluated by fetal MRI using the lung volume ratio and mediastinal shift. In patients with CLC, mediastinal shift and significant decreases in contralateral lung volumes during the fetal stages are good prenatal predictors of postnatal emergency lung resection.
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Malformación Adenomatoide Quística Congénita del Pulmón/diagnóstico por imagen , Imagen por Resonancia Magnética , Neumonectomía , Diagnóstico Prenatal/métodos , Malformación Adenomatoide Quística Congénita del Pulmón/cirugía , Técnicas de Apoyo para la Decisión , Urgencias Médicas , Femenino , Humanos , Recién Nacido , Masculino , Embarazo , Probabilidad , Pronóstico , Estudios Retrospectivos , Índice de Severidad de la EnfermedadRESUMEN
Deep medullary veins drain into subependymal veins with four convergence zones and show parallel distribution patterns adjacent to the body or inferior horn and a radial pattern in the frontal horn or trigon of the lateral ventricle. As white matter imaging develops such as diffusion tensor imaging or susceptibility-weighted imaging, requirements for understanding of white matter structures are increasing, not only for understanding of neuronal tracts but also for that of other structures including the fine anatomy of white matter vessels. Some disorders are related to deep medullary veins and show characteristic distributions of the lesions indicating the relationship to the medullary veins. When lesions show a parallel or radial distribution pattern in the certebral deep white matter, disorders related to deep medullary veins should be considered for differential diagnosis. In this review, we discuss disorders related to deep medullary veins, including (a) anomalies of the medullary veins, (b) hemorrhagic disorders related to the medullary veins (diffuse vascular injury due to high-energy trauma, deep medullary vein engorgement/thrombosis in neonates), (c) inflammatory changes that spread along the medullary veins, (d) neoplasms within the medullary veins, and (e) metabolic changes that lead to altered visualization of medullary veins. Understanding the anatomic structure of medullary veins in the cerebral hemisphere and becoming familiar with disorders in which the medullary veins play a major role in disease development may be helpful in the interpretation of brain images. ©RSNA, 2017.
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Angiografía Cerebral/métodos , Venas Cerebrales/anomalías , Venas Cerebrales/diagnóstico por imagen , Trastornos Cerebrovasculares/diagnóstico por imagen , Angiografía por Tomografía Computarizada/métodos , Angiografía por Resonancia Magnética/métodos , Diagnóstico Diferencial , Humanos , Neuroimagen/métodosRESUMEN
We used functional magnetic resonance imaging to investigate how attended and non-attended hearing of a subject's own name (SON) captures his or her attention. It has been reported that SON presentation activates the medial prefrontal cortex (mPFC), which is considered to be the key region for self-recognition. However, it remains unclear whether non-attended SON presentation also activates the mPFC. We hypothesized that an attended SON should activate mPFC more than a non-attended SON. To test this hypothesis, we designed an experiment in which we manipulated the task-relevance of SON; in a name-detection task, SON was a target stimulus, whereas in a tone-judgment task, SON was unrelated to the task. In each condition, identical sets of sound stimuli were presented. SON activated mPFC in the name-detection task but not in the tone-judgment task, supporting our hypothesis. In contrast, non-attended SON activated midbrain reticular formation, thalamus, insula, auditory cortex, and precuneus. We interpreted these to be related to low-level, automatic SON detection. Thus, hearing one's own name in a non-attended condition does not primarily engage the mPFC, but recruits a cortico-subcortical auditory attention network; this may account for the oft-observed salience of SON.
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Atención/fisiología , Encéfalo/fisiología , Nombres , Percepción del Habla/fisiología , Estimulación Acústica , Adulto , Encéfalo/diagnóstico por imagen , Mapeo Encefálico , Femenino , Humanos , Juicio/fisiología , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Percepción de la Altura Tonal/fisiología , Tiempo de Reacción , Autoimagen , Adulto JovenRESUMEN
More than 5 years have passed since the Diffusion Tensor Image Analysis ALong the Perivascular Space (DTI-ALPS) method was proposed with the intention of evaluating the glymphatic system. This method is handy due to its noninvasiveness, provision of a simple index in a straightforward formula, and the possibility of retrospective analysis. Therefore, the ALPS method was adopted to evaluate the glymphatic system for many disorders in many studies. The purpose of this review is to look back and discuss the ALPS method at this moment.The ALPS-index was found to be an indicator of a number of conditions related to the glymphatic system. Thus, although this was expected in the original report, the results of the ALPS method are often interpreted as uniquely corresponding to the function of the glymphatic system. However, a number of subsequent studies have pointed out the problems on the data interpretation. As they rightly point out, a higher ALPS-index indicates predominant Brownian motion of water molecules in the radial direction at the lateral ventricular body level, no more and no less. Fortunately, the term "ALPS-index" has become common and is now known as a common term by many researchers. Therefore, the ALPS-index should simply be expressed as high or low, and whether it reflects a glymphatic system is better to be discussed carefully. In other words, when a decreased ALPS-index is observed, it should be expressed as "decreased ALPS-index" and not directly as "glymphatic dysfunction". Recently, various methods have been proposed to evaluate the glymphatic system. It has become clear that these methods also do not seem to reflect the entirety of the extremely complex glymphatic system. This means that it would be desirable to use various methods in combination to evaluate the glymphatic system in a comprehensive manner.
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Imagen de Difusión Tensora , Sistema Glinfático , Humanos , Imagen de Difusión Tensora/métodos , Sistema Glinfático/diagnóstico por imagen , Encéfalo/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodosRESUMEN
PURPOSE: The effect of temporal sampling rate (TSR) on perfusion parameters has not been fully investigated in Moyamoya disease (MMD); therefore, this study evaluated the influence of different TSRs on perfusion parameters quantitatively and qualitatively by applying simultaneous multi-slice (SMS) dynamic susceptibility contrast-enhanced MR imaging (DSC-MRI). METHODS: DSC-MRI datasets were acquired from 28 patients with MMD with a TSR of 0.5 s. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and time to maximum tissue residue function (Tmax) were calculated for eight TSRs ranging from 0.5 to 4.0 s in 0.5-s increments that were subsampled from a TSR of 0.5 s datasets. Perfusion measurements and volume for chronic ischemic (Tmax ≥ 2 s) and non-ischemic (Tmax < 2 s) areas for each TSR were compared to measurements with a TSR of 0.5 s, as was visual perfusion map analysis. RESULTS: CBF, CBV, and Tmax values tended to be underestimated, whereas MTT and TTP values were less influenced, with a longer TSR. Although Tmax values were overestimated in the TSR of 1.0 s in non-ischemic areas, differences in perfusion measurements between the TSRs of 0.5 and 1.0 s were generally minimal. The volumes of the chronic ischemic areas with a TSR ≥ 3.0 s were significantly underestimated. In CBF and CBV maps, no significant deterioration was noted in image quality up to 3.0 and 2.5 s, respectively. The image quality of MTT, TTP, and Tmax maps for the TSR of 1.0 s was similar to that for the TSR of 0.5 s but was significantly deteriorated for the TSRs of ≥ 1.5 s. CONCLUSION: In the assessment of MMD by SMS DSC-MRI, application of TSRs of ≥ 1.5 s may lead to deterioration of the perfusion measurements; however, that was less influenced in TSRs of ≤ 1.0 s.
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Enfermedad de Moyamoya , Humanos , Enfermedad de Moyamoya/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Perfusión , Circulación CerebrovascularRESUMEN
Interest in interstitial fluid dynamics has increased since the proposal of the glymphatic system hypothesis. Abnormal dynamics of the interstitial fluid have been pointed out to be an important factor in various pathological statuses. In this article, we propose the concept of central nervous system interstitial fluidopathy as a disease or condition in which abnormal interstitial fluid dynamics is one of the important factors for the development of a pathological condition. We discuss the aspects of interstitial fluidopathy in various diseases, including Alzheimer's disease, Parkinson's disease, normal pressure hydrocephalus, and cerebral small vessel disease. We also discuss a method called "diffusion tensor image analysis along the perivascular space" using MR diffusion images, which is used to evaluate the degree of interstitial fluidopathy or the activity of the glymphatic system.
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PURPOSE: The purpose of this study was to evaluate the interstitial fluid status in a wide range of age groups using diffusion-weighted image analysis along the perivascular space (DWI-ALPS) method, which is a simplified variation of diffusion tensor image analysis along the perivascular space (DTI-ALPS). MATERIALS AND METHODS: This retrospective study included data from 128 patients who underwent clinical magnetic resonance imaging (MRI) studies, including DWI, and were found to have no abnormal findings in the brain on MRI. Three motion-probing gradients of the DWI were applied in an orthogonal direction to the imaging plane. Apparent diffusion coefficient images in the x-, y-, and z-axes were retrospectively generated, and composite color images were created to locate the projection and association fiber area on the slice including the body of the lateral ventricle. ALPS indices were calculated, and correlations with age were evaluated using linear and second-degree regression analysis. Linear regression analysis was also performed for a subgroup of patients older than 40 years. In addition, an analysis of variance (ANOVA) test among the generations was performed. RESULTS: The linear regression analysis between age and the ALPS index showed a correlation coefficient of -0.20 for all age group and -0.51 for the subgroup older than 40 years. The second-degree regression analysis showed a correlation coefficient of 0.39. ANOVA showed that the 40's generation showed a statistically significant higher value of ALPS index compared to all other generations except for the 30's generation. While, the 70's generation showed a statistically significant lower value of the ALPS index compared to all other generations. CONCLUSIONS: The analysis of the DWI-APLS method showed a correlation between age and the ALPS index in second-degree distribution which peaked in the 40's generation. This finding in normal subjects may be fundamental in the analysis of disease cases. We tried to evaluate the glymphatic system status in a wide range of age groups using diffusion-weighted image analysis along the perivascular space (DWI-ALPS) method, and the results showed a correlation between age and the ALPS index in second-degree distribution which peaked in the 40's generation.
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Sistema Glinfático , Adulto , Imagen de Difusión por Resonancia Magnética/métodos , Líquido Extracelular/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Estudios RetrospectivosRESUMEN
PURPOSE: The diffusion tensor image analysis along the perivascular space (DTI-ALPS) method was developed to evaluate the brain's glymphatic function or interstitial fluid dynamics. This study aimed to evaluate the reproducibility of the DTI-ALPS method and the effect of modifications in the imaging method and data evaluation. MATERIALS AND METHODS: Seven healthy volunteers were enrolled in this study. Image acquisition was performed for this test-retest study using a fixed imaging sequence and modified imaging methods which included the placement of region of interest (ROI), imaging plane, head position, averaging, number of motion-proving gradients, echo time (TE), and a different scanner. The ALPS-index values were evaluated for the change of conditions listed above. RESULTS: This test-retest study by a fixed imaging sequence showed very high reproducibility (intraclass coefficient = 0.828) for the ALPS-index value. The bilateral ROI placement showed higher reproducibility. The number of averaging and the difference of the scanner did not influence the ALPS-index values. However, modification of the imaging plane and head position impaired reproducibility, and the number of motion-proving gradients affected the ALPS-index value. The ALPS-index values from 12-axis DTI and 3-axis diffusion-weighted image (DWI) showed good correlation (r = 0.86). Also, a shorter TE resulted in a larger value of the ALPS-index. CONCLUSION: ALPS index was robust under the fixed imaging method even when different scanners were used. ALPS index was influenced by the imaging plane, the number of motion-proving gradient axes, and TE in the imaging sequence. These factors should be uniformed in the planning ALPS method studies. The possibility to develop a 3-axis DWI-ALPS method using three axes of the motion-proving gradient was also suggested.
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Imagen de Difusión Tensora , Líquido Extracelular , Imagen de Difusión por Resonancia Magnética , Humanos , Procesamiento de Imagen Asistido por Computador , Reproducibilidad de los ResultadosRESUMEN
PURPOSE: Decrease in signal of the cerebrospinal fluid (CSF) on low b-value diffusion weighted image (DWI) due to non-uniform flow can provide additional information regarding CSF motion. The purpose of the current study was to evaluate whether arterial pulsations constitute the driving force of CSF motion. METHODS: We evaluated the CSF signals within the Sylvian fissure on low b-value DWI in 19 patients with unilateral middle cerebral artery (MCA) occlusion. DWI with b-value of 500 s/mm2 was evaluated for a decrease in CSF signal within the Sylvian fissure including the Sylvian vallecula and lower, middle, and higher Sylvian fissures and graded as follows: the same as contralateral side; smaller signal decrease than that on contralateral side; and no signal decrease. MR angiography (MRA) findings of MCA were graded as follows: the same as contralateral, lower signal than contralateral signal, and no signal. In 15 patients, regional cerebral blood flow (rCBF) was evaluated using single-photon emission computed tomography (SPECT) studies and graded as >90%, 90%-70%, and <70% rCBF compared to contralateral. The correlations between the gradings were evaluated using G likelihood-ratio test. RESULTS: There was no statistically significant correlation between the MRA and low b-value DWI gradings of CSF in all areas. There were statistically significant correlations between the decreases in CBF on SPECT and CSF signals in the middle Sylvian fissure. CONCLUSION: The driving force of CSF pulsation in the Sylvian sinus may be related to the pulsations of the cerebral hemisphere rather than direct arterial pulsations.
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Imagen de Difusión por Resonancia Magnética , Infarto de la Arteria Cerebral Media , Corteza Cerebral , Circulación Cerebrovascular , Humanos , Arteria Cerebral Media/diagnóstico por imagen , Movimiento (Física)RESUMEN
PURPOSE: To visualize and analyze the dynamics of cerebrospinal fluid (CSF) motion in the cranium, we evaluated the distribution of motion-related signal dephasing by CSF on Diffusion ANalysis of fluid DYnamics with Incremental Strength of Motion proving gradient (DANDYISM) method, a composite imaging method using various low b values. MATERIALS AND METHODS: This study examined ten subjects aged 25-58. We acquired DWIs on a 3T clinical scanner with b values 0, 50, 100, 200, 300, 500, 700, and 1000 s/mm2 in total imaging time of 4 min. We constructed DANDYISM images and evaluated the CSF area distribution with decreased motion-dephasing signal using a scoring method. RESULTS: The DANDYISM images showed statistically significant higher CSF scores in the ventral posterior fossa, suprasellar cistern, and Sylvian vallecula compared to the lateral ventricle and frontal and parietal CSF spaces, indicating greater CSF movement in the former areas. CONCLUSION: The results indicated prominent CSF motions in the ventral portion of the posterior fossa, suprasellar cistern, and Sylvian fissure but smaller motions in the lateral ventricles and parietal subarachnoid space. This method may provide information of CSF dynamics in the clinical settings within short imaging time.
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Encéfalo/diagnóstico por imagen , Líquido Cefalorraquídeo/fisiología , Adulto , Encéfalo/fisiología , Imagen de Difusión por Resonancia Magnética , Humanos , Hidrodinámica , Imagenología Tridimensional , Persona de Mediana Edad , Movimiento (Física) , MovimientoRESUMEN
Neurite orientation dispersion and density imaging (NODDI) is a novel diffusion method for evaluating tissue microstructure, and may provide additional information over conventional diffusion tensor imaging (DTI). We evaluated NODDI and DTI parameters in cases of tuberous sclerosis (TS) to assess microstructural changes in the white matter. Eleven cases of tuberous sclerosis and eight age-matched controls underwent NODDI and DTI. We performed qualitative analysis and tract-based spatial statistics (TBSS) analysis of the NODDI parameters (Ficv: intracellular volume fraction, Fiso: isotropic fraction, ODI: orientation dispersion index) as well as DTI parameters (MD: mean diffusivity, FA: fractional anisotropy). We also performed a correlation analysis between clinical symptoms and parameters. The qualitative analysis indicated that the Ficv had a lower value in TS cases particularly in the tubers adjacent to the white matter. The TBSS analysis showed that the TS cases had decreased Ficv in a greater area compared to the other parameters including MD. In particular, the Ficv was decreased in deep white matter, such as the superior longitudinal fascicles (SLF). The application of NODDI to TS cases revealed tissue microstructural changes, and particularly the Ficv could detect more widespread abnormalities in white matter structure compared to DTI parameters.
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Imagen de Difusión Tensora , Neuritas/metabolismo , Esclerosis Tuberosa/diagnóstico por imagen , Esclerosis Tuberosa/patología , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Adolescente , Niño , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , MasculinoRESUMEN
BACKGROUND: Advances in hematopoietic stem cell transplantation have improved the survival rate of malignant diseases and congenital immunodeficiencies. It has become important to assess long-term complications in survivors. To assess neurological abnormalities in children treated by transplantation, diffusion tensor imaging was performed. METHODS: Forty children who underwent head diffusion tensor imaging before and after their first transplantation were enrolled. Patients with brain lesions on conventional MRI were excluded. Fractional anisotropy and mean diffusivity were compared between patients and 28 control subjects using tract-based spatial statistics. The Strengths and Difficulties Questionnaire was administered as a behavioral evaluation after transplantation, and diffusion tensor images of patients with and without behavioral abnormalities were compared. RESULTS: The age of patients and controls was 0 to 19 years and 0 to 16 years, respectively. The date of diffusion tensor imaging was 10 to 57 days before and 40 to 153 days after transplantation. Tract-based spatial statistics showed fractional anisotropy reduction in widespread white matter in patients before and after transplantation. Mean diffusivity was high before transplantation and normalized after transplantation. Analysis comparing before and after hematopoietic stem cell transplantation shows no difference in fractional anisotropy and a higher mean diffusivity before hematopoietic stem cell transplantation. In patients with behavioral abnormalities, low fractional anisotropy and high mean diffusivity remained after transplantation. CONCLUSIONS: Longitudinal diffusion tensor imaging showed white matter abnormalities in children without conventional MRI abnormalities, which were related to behavioral problems after transplantation. Diffusion tensor imaging is useful for behavioral assessment in children undergoing transplantation.
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Síntomas Conductuales/diagnóstico , Imagen de Difusión Tensora , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Leucoencefalopatías/diagnóstico por imagen , Leucoencefalopatías/etiología , Adolescente , Adulto , Enfermedades de la Médula Ósea/terapia , Niño , Preescolar , Femenino , Humanos , Lactante , Estudios Longitudinales , Masculino , Neoplasias/terapia , Enfermedades de Inmunodeficiencia Primaria/terapia , Adulto JovenRESUMEN
PURPOSE: It has been reported that leakage of intravenously administered gadolinium-based contrast agents (IV-GBCAs) into the cerebrospinal fluid (CSF) from the cortical veins even in healthy subjects can be detected using a highly sensitive pulse sequence such as heavily T2-weighted 3D fluid-attenuated inversion recovery and 3D-real inversion recovery (IR). The purpose of this study was to evaluate the feasibility of MR fingerprinting to detect GBCA leakage from the cortical veins after IV-GBCA. MATERIALS: Fourteen patients with suspected endolymphatic hydrops (EH) who received a single dose of IV-GBCA (39-79 years old) were included. The real IR images as well as MR fingerprinting images were obtained at 4 h after IV-GBCA. T1 and T2 values were obtained using MR fingerprinting and analyzed in ROIs covering intense GBCA leakage, and non-leakage areas of the CSF as determined on real IR images. The scan time for real IR imaging was 10 min and that for MR fingerprinting was 41 s. RESULTS: The mean T1 value of the ROI in the area of GBCA leakage was 2422 ± 261 ms and that in the non-leakage area was 3851 ± 235 ms (P < 0.01). There was no overlap between the T1 values in the area of GBCA leakage and those in the non-leakage area.The mean T2 value in the area of GBCA leakage was 319 ± 90 ms and that in the non-leakage area was 670 ± 166 ms (P < 0.01). There was some overlap between the T2 values in the area of GBCA leakage and those in the non-leakage area. CONCLUSION: Leaked GBCA from the cortical veins into the surrounding CSF can be detected using MR fingerprinting obtained in <1 min.
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Líquido Cefalorraquídeo/diagnóstico por imagen , Medios de Contraste/efectos adversos , Gadolinio/efectos adversos , Imagenología Tridimensional/métodos , Imagen por Resonancia Magnética/métodos , Adulto , Anciano , Líquido Cefalorraquídeo/química , Medios de Contraste/administración & dosificación , Medios de Contraste/química , Hidropesía Endolinfática/diagnóstico por imagen , Gadolinio/administración & dosificación , Gadolinio/química , Humanos , Persona de Mediana EdadRESUMEN
PURPOSE: We aimed to investigate whether low b value diffusion-weighted imaging (DWI) can show the change of cerebrospinal fluid (CSF) dynamics. MATERIALS AND METHODS: The subjects of this retrospective study consisted of patients with ventricular dilatation (n = 50) and controls (n = 50). The CSF signal intensity on the b = 500 s/mm2 DWI was evaluated by a scoring method in the lateral, 3rd and 4th ventricles, the cerebral sulci and the Sylvian fissure. The signal void findings adjacent to the septum pellucidum were also evaluated. RESULTS: The CSF signal intensities were significantly less in lateral ventricle and 3rd ventricle of the ventricular dilatation subjects. In controls, the score for the signal void in the Sylvian fissure showed a significant positive correlation with age. However, other areas did not show a significant correlation with age. The appearance of the characteristic signal void adjacent to the septum pellucidum showed a significant correlation with ventricular dilatation. CONCLUSION: Our current study suggests that the CSF signal intensity on the b = 500 s/mm2 DWI may show the changes in CSF dynamics and might be useful to evaluate the overlook of CSF dynamics.
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Líquido Cefalorraquídeo/diagnóstico por imagen , Líquido Cefalorraquídeo/fisiología , Imagen de Difusión por Resonancia Magnética/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Encéfalo/diagnóstico por imagen , Niño , Preescolar , Femenino , Hemodinámica , Humanos , Lactante , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto JovenRESUMEN
PURPOSE: It has been reported that intravenously administered gadolinium-based contrast agents (IV-GBCAs) leak into the cerebrospinal fluid (CSF) even in healthy subjects. The purpose of this study was to evaluate GBCA leakage from the cortical veins in patients with delayed imaging after IV-GBCA. MATERIALS AND METHODS: There are two parts of retrospective study. In the first part, we reviewed six patients with suspected endolymphatic hydrops (EH) who received a single dose of IV-GBCA (37-58 years old). The 3D-real inversion recovery images were obtained prior to the contrast administration as well as 5 min and 4 h after IV-GBCA. Leakage from the cortical veins to the CSF was graded as positive if enhancement around the cortical veins at 5 min was observed and had further spread into the CSF at 4 h after IV-GBCA.In the second part of this study, we reviewed 21 patients with suspected EH (17-69 years old). Images were obtained only at 4 h after IV-GBCA. The number of slices (NOS) with a positive GBCA leakage from the cortical veins was counted. The correlation of the NOS with age, gender, and degree of EH was evaluated by Spearman's rank correlation coefficient. RESULTS: In the first part of the study, the GBCA leakage from the cortical veins was positive in all patients. In the second part of the study, the GBCA leakage from the cortical veins was seen in all older patients (above 37 years old), but not in the five younger patients (younger than 37 years old). The NOS correlated significantly only with age (r = 0.755, P < 0.01), but not with gender or degree of EH. CONCLUSION: IV-GBCA leaks from the cortical veins into the surrounding CSF. The leakiness of the cortical veins significantly correlated with age, but not with gender or degree of EH.
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Encéfalo/diagnóstico por imagen , Líquido Cefalorraquídeo/fisiología , Medios de Contraste/administración & dosificación , Hidropesía Endolinfática/diagnóstico por imagen , Gadolinio/administración & dosificación , Imagen por Resonancia Magnética/métodos , Administración Intravenosa , Adolescente , Adulto , Anciano , Femenino , Voluntarios Sanos , Humanos , Imagenología Tridimensional/métodos , Inyecciones Intravenosas , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto JovenRESUMEN
Recent technical advances have enabled the visualization of neuromelanin in the substantia nigra pars compacta (SNc) and locus ceruleus (LC) by 3-tesla (T) magnetic resonance imaging in vivo. In the present study, we successfully detected neuromelanin in the SNc and LC of 6 healthy volunteers at 1.5T using a 3D gradient echo sequence with off-resonance magnetization transfer contrast.
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Locus Coeruleus/química , Imagen por Resonancia Magnética/métodos , Melaninas/análisis , Sustancia Negra/química , Adulto , Femenino , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
PURPOSE: To elucidate differences between the perivascular space (PVS) in the basal ganglia (BG) versus that found in white matter (WM) using heavily T2-weighted FLAIR (hT2-FL) in terms of 1) signal intensity on non-contrast enhanced images, and 2) the degree of contrast enhancement by intravenous single dose administration of gadolinium based contrast agent (IV-SD-GBCA). MATERIALS AND METHODS: Eight healthy men and 13 patients with suspected endolymphatic hydrops were included. No subjects had renal insufficiency. All subjects received IV-SD-GBCA. MR cisternography (MRC) and hT2-FL images were obtained prior to and 4 h after IV-SD-GBCA. The signal intensity of the PVS in the BG, subinsular WM, and the cerebrospinal fluid (CSF) in Ambient cistern (CSFAC) and CSF in Sylvian fissure (CSFSyl) was measured as well as that of the thalamus. The signal intensity ratio (SIR) was calculated by dividing the intensity by that of the thalamus. We used 5% as a threshold to determine the significance of the statistical test. RESULTS: In the pre-contrast scan, the SIR of the PVS in WM (Mean ± standard deviation, 1.83 ± 0.46) was significantly higher than that of the PVS in the BG (1.05 ± 0.154), CSFSyl (1.03 ± 0.15) and the CSFAC (0.97 ± 0.29). There was no significant difference between the SIR of the PVS in the BG compared to the CSFAC and CSFSyl. For the evaluation of the contrast enhancement effect, significant enhancement was observed in the PVS in the BG, the CSFAC and the CSFSyl compared to the pre-contrast scan. No significant contrast enhancement was observed in the PVS in WM. CONCLUSION: The signal intensity difference between the PVS in the BG versus WM on pre-contrast images suggests that the fluid composition might be different between these PVSs. The difference in the contrast enhancement between the PVSs in the BG versus WM suggests a difference in drainage function.
Asunto(s)
Ganglios Basales/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Sustancia Blanca/diagnóstico por imagen , Líquido Cefalorraquídeo/diagnóstico por imagen , Hidropesía Endolinfática/diagnóstico por imagen , Humanos , MasculinoRESUMEN
OBJECTIVE: To compare magnetic resonance spectroscopy (MRS) metabolite ratios in preterm infants at term-equivalent age with those in term infants and to evaluate the association between MRS metabolites and neurodevelopmental outcomes at 18 months corrected age in preterm infants. DESIGN: We studied infants born at a gestational age <37 weeks and weighing <1500 g during 2009-2013 using MRS at term-equivalent age. Infants with major brain abnormalities were excluded. The ratios of N-acetylaspartate (NAA) to creatine (Cre), NAA to choline-containing compounds (Cho) and Cho to Cre in the frontal white matter and thalamus were measured using multivoxel point-resolved proton spectroscopy sequence. Neurodevelopmental outcomes were assessed at 18 months corrected age. RESULTS: Thirty-three preterm infants and 16 term infants were enrolled in this study. Preterm infants with normal development at 18 months showed significantly lower NAA/Cho ratios in the frontal white matter than term infants. There were no differences in the Cre/Cho ratios between preterm and term infants. At 18 months corrected age, 9 preterm infants with a mild developmental delay showed significantly lower NAA/Cho ratios in the thalamus than 24 preterm infants with normal development. CONCLUSIONS: Preterm infants at term-equivalent age showed reduced MRS metabolites (NAA/Cho) compared with term infants. Decreased NAA/Cho ratios in the thalamus were associated with neurodevelopmental delay at 18 months corrected age in preterm infants.
Asunto(s)
Encéfalo/metabolismo , Desarrollo Infantil , Recien Nacido Prematuro/metabolismo , Espectroscopía de Resonancia Magnética/métodos , Trastornos del Neurodesarrollo/metabolismo , Ácido Aspártico/análogos & derivados , Ácido Aspártico/metabolismo , Colina/metabolismo , Creatina/metabolismo , Femenino , Humanos , Lactante , Recién Nacido , Imagen por Resonancia Magnética/métodos , Masculino , Trastornos del Neurodesarrollo/diagnósticoRESUMEN
PURPOSE: In textbooks, the perivascular space (PVS) is described as non-enhancing after the intravenous administration of gadolinium-based contrast agent (IV-GBCA). We noticed that the PVS sometimes has high signal intensity (SI) on heavily T2-weighted 3D-FLAIR (hT2-FL) images obtained 4 h after IV-GBCA. The purpose of this study was to retrospectively evaluate the contrast enhancement of the PVS. MATERIALS AND METHODS: In 8 healthy subjects and 19 patients with suspected endolymphatic hydrops, magnetic resonance cisternography (MRC) and hT2-FL images were obtained before and 4 h after a single dose of IV-GBCA. No subjects had renal insufficiency. On axial MRC at the level of the anterior commissure (AC)-posterior commissure (PC) line, 1 cm circular regions of interest (ROIs) were drawn centering on the PVS in the bilateral basal ganglia and thalami. Three-millimeter diameter ROIs were set in the cerebrospinal fluid (CSF) of the bilateral ambient cistern. The ROIs on MRC were copied onto the hT2-FL images and the SI was measured. The SI ratio (SIR) was defined as SIRPVS = SI of PVS/SI of the thalami, and SIRCSF = SI of CSF/SI of the thalami. The average of the bilateral values was used for the calculation. The SIRCSF, SIRPVS, and SI of the thalami were compared between before and 4 h after IV-GBCA. RESULTS: The SIR was increased significantly from 1.02 ± 0.37 to 2.65 ± 0.82 in the CSF (P < 0.01) and from 1.20 ± 0.35 to 2.13 ± 1.23 in the PVS at 4 h after IV-GBCA (P < 0.01). The SI of the thalami showed no significant difference. CONCLUSION: The enhancement of the PVS at 4 h after IV-GBCA was confirmed even in subjects without renal insufficiency. It is possible that the GBCA in the blood vessels might have permeated into the cerebrospinal fluid (CSF) space and the PVS. This might be a first step in the imaging evaluation of the glymphatic system (waste clearance system) of the brain.