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BACKGROUND AND PURPOSE: Odor preference is one of the key factors for the rehabilitation of the swallowing function. On the other hand, sensitivity to odor differs between sexes and decreases with age. These factors rely on brain neuronal circuits. However, it remains not fully clarified which neuronal circuit determines the sex and age differences in odor sensitivity. In this study, we carried out both the odor sensitivity test and functional MRI (fMRI) to find the key neuronal circuits determining sex and age differences in odor sensitivity. METHODS: Healthy volunteers (28 males, aged 27-62 years, and 30 females, aged 21-59 years) participated in this study. Some of them (seven males and seven females) underwent fMRI. We prepared five odorous test substances and presented each substance at 1 minute intervals. After 5 minutes of questioning about food intake, the subjects were asked to recall each of the test substances presented from the list. In the fMRI study, all the subjects underwent 15 minutes of the prestimulation, stimulation with peppermint odor, and poststimulation sessions. RESULTS: The odor test score was significantly higher in females than in males and showed an age-dependent decrease. We found four functional connectivities whose degrees were significantly different between males and females. One of them, the functional connectivity between the frontal medial cortex (MedFC) and the left angular gyrus (AG. l), showed an age-dependent change. CONCLUSIONS: The functional MedFC-AG.l connectivity is one of the important neuronal circuits that affect the sex- and age-dependent odor sensitivity.
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Odorantes , Lóbulo Parietal , Femenino , Sustancia Gris , Voluntarios Sanos , Humanos , Imagen por Resonancia Magnética/métodos , MasculinoRESUMEN
PURPOSE: We performed echo-planar imaging (EPI) and turbo spin-echo (TSE) diffusion-weighted imaging (DWI) using magnetic resonance imaging (MRI) to obtain basic clinical data of the apparent diffusion coefficient (ADC) in various parts of normal brains and compared the datasets using our retrospective distortion correction technique. MATERIALS AND METHODS: The normal brains of 32 patients who underwent health check were scanned on a 1.5-T MRI instrument using EPI- and TSE-DWI. Distortion was corrected by (1) segmentation: the b0 images were segmented based on the plural threshold values; (2) edge detection: the edge was detected in the images obtained in step (1); (3) non-rigid image registration: non-rigid image registration using Demons algorithm was achieved between the b0 images of EPI-DWI and TSE-DWI, thereby, creating a displacement field; and (4) image warp: the displacement field was applied to the b1000 image to warp. Twenty-six parts of the brain were measured from the images of b0 and b1000 and the ADCs were calculated. The signal-to-noise ratio (SNR) of the cerebrospinal fluid was measured to identify the cause of the difference between the two sequences. These were compared using Wilcoxon signed-rank test (P = 0.05). RESULTS: The ADC was significantly higher measured by EPI-DWI than by TSE-DWI. The SNR of EPI-DWI was significantly higher than that of the TSE-DWI. CONCLUSION: Care must be taken when measuring ADCs near the base of the skull, such as the brain stem, where the SNR of the imaging technique is likely to decrease or distort.
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Imagen de Difusión por Resonancia Magnética , Imagen Eco-Planar , Encéfalo/diagnóstico por imagen , Imagen de Difusión por Resonancia Magnética/métodos , Imagen Eco-Planar/métodos , Humanos , Reproducibilidad de los Resultados , Estudios RetrospectivosRESUMEN
OBJECTIVE: Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) is now recommended as a first-line staging modality in prostate cancer patients, and the widespread use of DWIBS may lead to an increased frequency of incidental findings. The aim of this study was to evaluate the prevalence and clinical significance of incidental findings on whole-body magnetic resonance imaging (WB-MRI) with DWIBS. METHODS: Data from 124 patients with prostate cancer (age, 76.5 ± 5.6 years), who underwent 1.5 T WB-MRI with STIR, TSE-T2, TSE-T1, In/Out GRE, and DWIBS sequences, were retrospectively analyzed. Findings unrelated to prostate cancer were considered as incidental findings and categorized into two groups based on their clinical implications as follows: imaging follow-up or additional examinations was required (significant incidental findings) and no need to additional work-up (non-significant incidental findings). A chi-square test was performed to compare the differences in the prevalence of significant incidental findings based on age (≤75 and>75 years old). RESULTS: A total of 334 incidental findings were found with 8.1% (n = 27) as significant incidental findings. Significant incidental findings were more frequent in patients over 75 years old than those of 75 years old or younger (28.6% vs 11.1%, p = 0.018). CONCLUSION: Clinically significant incidental findings, which required imaging follow-up or additional examinations, were commonly observed in prostate cancer patients on WB-MRI/DWIBS. ADVANCES IN KNOWLEDGE: Some incidental findings were clinically significant that may lead to changes in treatment strategy. Checking the entire organ carefully for abnormalities and reporting any incidental findings detected are important.
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Imagen de Difusión por Resonancia Magnética/métodos , Hallazgos Incidentales , Neoplasias de la Próstata/diagnóstico por imagen , Imagen de Cuerpo Entero/métodos , Anciano , Humanos , Masculino , Prevalencia , Estudios RetrospectivosRESUMEN
BACKGROUND: Gray matter (GM) imaging is important in the investigation of many neurological diseases, including schizophrenia, multiple sclerosis, stroke, Alzheimer's disease, tuberous sclerosis, and epilepsy, which are all associated with changes in cortical GM. OBJECTIVE: The aim of this study was to develop a quantitative statistical analysis system for double inversion recovery (DIR) MRI and to evaluate the new system using preliminary clinical data. METHODS: The study population comprised of 10 healthy volunteers and six patients with or without brain degeneration. A quantitative statistical analysis system for DIR images was developed using the following steps: 1) brain spatial normalization, 2) mean and standard deviation (SD) map creation, and 3) Z-score map creation. To evaluate the new voxel-based morphometry system, Z-scores of lesions in patients with brain degeneration were measured and then compared with Z-scores of normal regions. RESULTS: All DIR images were adequately spatially normalized to Montreal Neurological Institute MNI coordinate. Lesions in each patient were indicated by high Z-score values on a Z-score map, which were significantly higher than Z-scores of normal regions (p< 0.05). CONCLUSIONS: In this study, we developed a quantitative statistical analysis system for DIR MRI. Using our system, clinicians might accurately diagnose early brain degeneration.
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Encefalopatías/diagnóstico por imagen , Encéfalo/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Encéfalo/patología , Encefalopatías/patología , Femenino , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/patología , Humanos , Masculino , Persona de Mediana Edad , Análisis Espacial , Adulto JovenRESUMEN
PURPOSE: Dynamic contrast enhancement (DCE)-MRI has high diagnostic performance of prostate cancer. However, it is preferable to avoid the use of MRI contrast media. A study reported that the diagnosability of the wash-in index of DCE-MRI was equivalent to the intravoxel incoherent motion of the diffusion weighted image. The purpose of this study was to examine the correlation between the slow component apparent diffusion coefficient (ADC) and the wash-out index of the DCE. MATERIALS AND METHODS: Thirty-eight patients diagnosed with prostate cancer by biopsy were enrolled in this study. The fast and slow component ADCs of the DWI were calculated for 76 points of the tumor and the contralateral normal parts. Furthermore, the wash-in and wash-out indices of the DCE-MRI were calculated. The correlations for each calculated index were compared. RESULTS: There was a significant difference between the tumor and the contralateral normal parts for both fast (pâ¯=â¯0.03) and slow component (pâ¯<â¯0.01) ADCs. In addition, the slow component ADC was correlated with the wash-out index (râ¯=â¯0.64). CONCLUSION: The slow component ADC was correlated with the wash-out index, and may, therefore, be a suitable substitute for DCE-MRI.
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Medios de Contraste/farmacocinética , Próstata/diagnóstico por imagen , Neoplasias de la Próstata/diagnóstico por imagen , Anciano , Anciano de 80 o más Años , Biopsia , Imagen de Difusión por Resonancia Magnética , Gadolinio/farmacocinética , Humanos , Masculino , Persona de Mediana Edad , Movimiento (Física) , Reproducibilidad de los ResultadosRESUMEN
It is important to optimize imaging parameters in 3D-double inversion recovery (DIR) magnetic resonance imaging (MRI) for detecting cortical micro lesions. However, inadequate parameters markedly raise blurring in 3DDIR MRI. The purpose of this study was to evaluate the relationship between the blurring and refocus flip angle (RFA) in 3D-DIR MRI. White matter attenuated inversion recovery (WAIR) images as a test sample were obtained by 1.5T MRI with various RFA settings (30°, 40°, 60°, 100°, 140°, 180°, and variable refocus flip angle (VRFA)). Optimal RFA was evaluated using Scheffé's method (Nakaya changing method) by five observers. The results of average preferences indicated that RFA settings of under the 60° of RFA or VRFA suppressed the blurring in 3DDIR MRI. The yard sticks of RFAs of 30° and 40° were significantly higher than the yard sticks of other RFAs (p<0.01). For detecting cortical microlesions, it is very important to obtain WAIR images with no blurring. Using low RFA or VRFA didn't cause significant differences of signal intensity between high-frequency region and low-frequency region in k-space of 3D-DIR MRI. Therefore, it is recommended to set lower RFA (under 60° or VRFA) for suppressing blur in 3D-DIR MRI.
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Imagenología Tridimensional/métodos , Imagen por Resonancia Magnética/métodos , Femenino , Humanos , Masculino , Sustancia Blanca/diagnóstico por imagen , Adulto JovenRESUMEN
BACKGROUND: Optimizing scan parameters for double inversion recovery (DIR) sequences remains difficult. OBJECTIVE: To evaluate a new method for optimizing DIR sequence scan parameters using T1 mapping and a newly developed analysis algorithm. METHODS: Twelve healthy volunteers underwent T1 mapping and DIR magnetic resonance imaging. The following steps were used for image optimization including: 1) measurement of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) T1 values to create a T1 map; 2) calculation of optimized scan parameters by using a developed analysis algorithm; 3) performance assessment of DIR magnetic resonance imaging by using the calculated optimized imaging parameters. Additionally, we used scan parameters from previous studies to obtain DIR images in order to evaluate our new method. The contrast between GM and suppressed tissues was compared between these images and those obtained using the optimized parameters. RESULTS: Using our optimization method, WM and CSF regions were suppressed uniformly for all scan conditions. The contrast was significantly higher in images obtained using this optimization method compared to those obtained using previously published parameters (pâ<â0.01). CONCLUSIONS: It is possible to obtain superior DIR images by using an optimization method that involves T1 mapping and a newly developed analysis algorithm.
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Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Adulto , Algoritmos , Encéfalo/diagnóstico por imagen , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
We propose a practical method for setting the optimal inversion times (TI) for double inversion recovery (DIR) sequences. Our method used the measurement of signal intensity (SI) from real images to set the optimal TI for white-matter (WM) and gray-matter (GM)-attenuated inversion recovery (WAIR and GAIR, respectively) images. 3D-DIR images of healthy volunteers were obtained on 1.5- and 3.0-T magnetic resonance (MR) scanners and the SIs of GM, WM, and cerebrospinal fluid (CSF) were evaluated on real images. We found TI2s at which the SI of WM or GM was null. Then, we found TI1+2 (=TI1 + TI2) at which the SI of CSF was null. We defined the two TIs as optimal TIs. We assessed the utility of these TIs with additional volunteers and patients, and similar images were obtained with the determined TIs. Optimal TIs for DIR images could be efficiently determined using this method.
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Encéfalo/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Color , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
The depth of myometrial invasion in patients with endometrial carcinoma is recognized as an important factor that closely correlates with prognosis. Preoperative assessment of myometrial invasion is essential for planning surgery. To enhance the contrast between myometrium and endometrium including myometrial invasion with endometrial carcinoma, we optimized the sequence parameter with phase-sensitive inversion-recovery (PSIR) in gadolinium dynamic study of uterine corpus. On a 1.5-T magnetic resonance imaging (MRI), images were acquired by three-dimensional (3D) T1 -turbo field echo (TFE) with PSIR sequence and gadolinium-diethylenetriamine pentaacetic acid( Gd-DTPA) diluted phantom (0-5 mmol/L) and myometrium model (manganese chloride tetrahydrate+agar). We calculated the null point and the contrast-to-noise ratio (CNR) at multiple TFE inversion delay times, 200 ms-maximum in each combination; flip angles (FAs), 5-35 degrees; TFE factor, 20-40; and shot interval (SI), 500-1000 ms. We assumed that dynamic scanning time was 30 seconds when the sensitivity encoding factor was 2, namely, in this study, the scanning time was 1 minute with no sensitivity encoding. In addition, we compared CNR between optimized PSIR sequence ande-Thrive. We recognized a successful CNR of the 3D PSIR parameter was TFE inversion delay times, 335 ms; FA, 25 degrees; TFE factor, 20; and SI, 500 ms. In each gadolinium-DTPA diluted phantom, the average CNR of the optimized PSIR sequence was approximately 1.7 times (maximum: 3 times) higher than e-Thrive. Optimizing sequence parameter of PSIR is applicable in gadolinium dynamic study of uterine corpus.
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Imagen por Resonancia Magnética/métodos , Útero/fisiología , Femenino , Gadolinio DTPA , Humanos , Fantasmas de ImagenRESUMEN
The purpose of this study was to develop an optimizing program of scanning parameters for double inversion recovery (DIR) MRI. The optimization algorithm consists of the following steps: (1) obtaining the initial parameters (TR, TE, and T1 values of the two attenuated tissues); (2) iterative calculation for minimization of errors; and (3) determination of the optimized TI(1st) and TI(2nd). To evaluate the developed algorithm, we performed the phantom and simulation studies using the phantoms which were imitated T1 values of white and gray matters and cerebrospinal fluid. In addition, white matter attenuated inversion recovery (WAIR) and gray matter attenuated inversion recovery (GAIR) images were obtained by optimized scan parameters in one volunteer. The developed algorithm could calculate the optimized TI(1st) and TI(2nd) values at once. Results of summation of signal intensity (SI) of two attenuated tissues shows that the SI of the two tissues were well-attenuated using the theoretical values which were calculated using the developed algorithm. The correlation coefficient of the SI of the phantom of the gray matter between actual and simulation measurements was r=0.997. The SI obtained by actual measurements well correlated with the SI obtained by the simulation measurements. The WAIR and GAIR images in the volunteer were well enhanced gray or white matters. We thus conclude that it is possible to calculate the optimized parameters for the DIR-MRI using the developed algorithm.