PURPOSE: To report the use of multiband accelerated echo-planar imaging (EPI) for resting-state functional MRI (rs-fMRI) to achieve rapid high temporal resolution at 3T compared to conventional EPI. MATERIALS AND METHODS: rs-fMRI data were acquired from 20 healthy right-handed volunteers by using three methods: conventional single-band gradient-echo EPI acquisition (Data 1), multiband gradient-echo EPI acquisition with 240 volumes (Data 2) and 480 volumes (Data 3). Temporal signal-to-noise ratio (tSNR) maps were obtained by dividing the mean of the time course of each voxel by its temporal standard deviation. The resting-state sensorimotor network (SMN) and default mode network (DMN) were estimated using independent component analysis (ICA) and a seed-based method. One-way analysis of variance (ANOVA) was performed between the tSNR map, SMN, and DMN from the three data sets for between-group analysis. P < 0.05 with a family-wise error (FWE) correction for multiple comparisons was considered statistically significant. RESULTS: One-way ANOVA and post-hoc two-sample t-tests showed that the tSNR was higher in Data 1 than Data 2 and 3 in white matter structures such as the striatum and medial and superior longitudinal fasciculus. One-way ANOVA revealed no differences in SMN or DMN across the three data sets. CONCLUSION: Within the adapted metrics estimated under specific imaging conditions employed in this study, multiband accelerated EPI, which substantially reduced scan times, provides the same quality image of functional connectivity as rs-fMRI by using conventional EPI at 3T. Under employed imaging conditions, this technique shows strong potential for clinical acceptance and translation of rs-fMRI protocols with potential advantages in spatial and/or temporal resolution. However, further study is warranted to evaluate whether the current findings can be generalized in diverse settings.
Dataset ; Echo-Planar Imaging* ; Magnetic Resonance Imaging* ; Methods ; Signal-To-Noise Ratio ; Volunteers ; White Matter

This paper introduces the development of the Free-MPR module, based on VC++6.0 environment and VTK5.0, and on Windows XP platform. The Free-MPR module can adjust freely the display plane according to the change of the visual angle, and implement the free multi-planar reformation.
Echo-Planar Imaging ; Imaging, Three-Dimensional ; Software ; Tomography, X-Ray Computed ; methods

The popularity of magnetic resonance imaging over other imaging disciplines depends predominantly on its high spatial resolution, soft tissue contrast, no hard fake trace and no radiation injury. However, the ghost artifacts produced during a magnetic resonance imaging would degrade the image badly and affect the precise orientation to focus. This paper introduced the process of studies for reduction of ghost artifact resulting from EPI imaging theory and motion of subject. A lot of researches indicated that how to reduce the ghost effectively is still a challenging task. Researchers should persist in seeking for new method to solve the difficult problem.
Artifacts ; Echo-Planar Imaging ; instrumentation ; methods ; Humans ; Image Enhancement ; methods ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging ; methods ; Phantoms, Imaging

OBJECTIVE: It was reported lately that to obtain consistent liver T1rho measurement, at 3T MRI using six spin-lock times (SLTs), is feasible. In this study, the feasibility of using three or two SLT points to measure liver T1rho relaxation time was explored. MATERIALS AND METHODS: Seventeen healthy volunteers underwent 36 examinations. Three representative axial slices were selected to cut through the upper, middle, and lower liver. A rotary echo spin-lock pulse was implemented in a 2D fast field echo sequence. Spin-lock frequency was 500 Hz and the spin-lock times of 1, 10, 20, 30, 40, and 50 milliseconds (ms) were used for T1rho mapping. T1rho maps were constructed by using all 6 SLT points, three SLT points of 1, 20, and 50 ms, or two SLTs of 1 and 50 ms, respectively. Intra-class correlation coefficient (ICC) and Bland and Altman plot were used to assess the measurement agreement. RESULTS: Two examinations were excluded, due to motion artifact at the SLT of 50 ms. With the remaining 34 examinations, the ICC for 6-SLT vs. 3-SLT T1rho measurements was 0.922, while the ICC for 6-SLT vs. 2-SLT T1rho measurement was 0.756. The Bland and Altman analysis showed a mean difference of 0.19 (95% limits of agreement: -1.34, 1.73) for 6-SLT vs. 3-SLT T1rho measurement, and the mean difference of 0.89 (95% limits of agreement: -1.67, 3.45) for 6-SLT vs. 2-SLT T1rho measurement. The scan re-scan reproducibility ICC (n = 11 subjects) was 0.755, 0.727, and 0.528 for 6-SLT measurement, 3-SLT measurement, and 2-SLT measurement, respectively. CONCLUSION: Adopting 3 SLTs of 1, 20, and 50 ms can be an acceptable alternative for the liver T1rho measurement, while 2 SLTs of 1 and 50 ms do not provide reliable measurement.
Adult ; Eating ; Echo-Planar Imaging/*methods ; Fasting ; Female ; Humans ; Liver/*anatomy & histology ; Magnetic Resonance Imaging/*methods ; Male ; Young Adult

When a conventional phase-encoding magnetic resonance spectrascopic imaging(MRSI) method is in use, the data acquisition is very time consuming and thus it is not well accepted in clinical settings. Echo planar spectroscopic imaging (EPSI) technology has been applied for rapid acquisition of MRSI data. It significantly reduces scan time by simultaneously encoding the spectral dimension and the spatial dimension. Reconstruction of EPSI data is sophisticated. For the t-dimension, data are non-uniformly sampled. Fast Fourier transform (FFT) is applied in odd echoes and even echoes respectively and then shift method is used to combine them together. For the kx dimension, the data are unevenly sampled and have to be interpolated onto a Cartesian grid before FFT is applied. For the phase-encoding dimension (ky), the Fourier transform can be readily done with FFT since the data are evenly spaced.
Algorithms ; Echo-Planar Imaging ; methods ; Image Processing, Computer-Assisted ; methods ; Magnetic Resonance Spectroscopy ; methods ; Signal Processing, Computer-Assisted

OBJECTIVETo assess the reproducibility of whole-body diffusion weighted imaging (WB-DWI) technique in healthy volunteers under normal breathing with background body signal suppression.

METHODSWB-DWI was performed on 32 healthy volunteers twice within two-week period using short TI inversion-recovery diffusion-weighted echo-planar imaging sequence and built-in body coil. The volunteers were scanned across six stations continuously covering the entire body from the head to the feet under normal breathing. The bone apparent diffusion coefficient (ADC) and exponential ADC (eADC) of regions of interest (ROIs) were measured. We analyzed correlation of the results using paired-t-test to assess the reproducibility of the WB-DWI technique.

RESULTSWe were successful in collecting and analyzing data of 64 WB-DWI images. There was no significant difference in bone ADC and eADC of 824 ROIs between the paired observers and paired scans (P>0.05). Most of the images from all stations were of diagnostic quality.

CONCLUSIONThe measurements of bone ADC and eADC have good reproducibility. WB-DWI technique under normal breathing with background body signal suppression is adequate.

Adult ; Aged ; Diffusion Magnetic Resonance Imaging ; methods ; Echo-Planar Imaging ; methods ; Female ; Humans ; Image Processing, Computer-Assisted ; methods ; Male ; Middle Aged ; Reproducibility of Results ; Respiration ; Whole Body Imaging ; methods

OBJECTIVES: Magnetic resonance diffusion-weighted imaging (DWI) has important clinical value in diagnosis and curative effect evaluation on endometrial carcinoma. How to improve the detection rate of endometrial small lesions by DWI is the research focus of MRI technology. This study aims to analyze the image quality of small field MRI ZOOMit-DWI sequence and conventional single-shot echo-planar imaging (SS-EPI) DWI sequence in the scanning of endometrial carcinoma, and to explore the clinical value of ZOOMit-DWI sequence. METHODS: A total of 37 patients with endometrial carcinoma diagnosed by operation and pathology in the Second Xiangya Hospital of Central South University from July 2019 to May 2021 were collected. All patients were scanned with MRI ZOOMit-DWI sequence and SS-EPI DWI sequence before operation. Two radiologists subjectively evaluated the anatomical details, artifacts, geometric deformation and focus definition of the 2 groups of DWI images. At the same time, the signal intensity were measured and the signal-to-noise ratio (SNR), contrast to noise ratio (CNR), and apparent diffusion coefficient (ADC) of the 2 DWI sequences were calculated for objective evaluation. The differences of subjective score, objective score and ADC value of the 2 DWI sequences were analyzed. RESULTS: The SNR of the ZOOMit-DWI group was significantly higher than that of the SS-EPI DWI group (301.96±141.85 vs 94.66±41.26), and the CNR of the ZOOMit-DWI group was significantly higher than that of the SS-EPI DWI group (185.05±105.45 vs 57.91±31.54, P<0.05). There was no significant difference in noise standard deviation between the ZOOMit-DWI group and the SS-EPI DWI group (P>0.05). The subjective score of anatomical detail and focus definition in the ZOOMit-DWI group was significantly higher than that of the SS-EPI DWI group (both P<0.05). The subjective score of artifacts and geometric deformation of ZOOMit-DWI group was significantly lower than that of the SS-EPI DWI group (both P<0.05). ADC had no significant difference between the ZOOMit-DWI group and the SS-EPI DWI group (P>0.05). CONCLUSIONS The image quality of ZOOMit-DWI is significantly higher than that of conventional SS-EPI DWI. In the MRI DWI examination of endometrial carcinoma, ZOOMit-DWI can effectively reduce the geometric deformation and artifacts of the image, which is more conducive to clinical diagnosis and treatment.
Female ; Humans ; Signal-To-Noise Ratio ; Endometrial Neoplasms/diagnostic imaging* ; Diffusion Magnetic Resonance Imaging/methods* ; Endometrium ; Echo-Planar Imaging/methods* ; Reproducibility of Results

OBJECTIVETo analyze the renal relative blood flow value (rBFV) and image quality in normal adults using single-shot fast spin echo, flow sensitive invention recovery (SSFSE-FAIR) magnetic resonance (MR) sequence and echo planar imaging, and flow sensitive invention recovery (EPI-FAIR) MR sequence, and assess its value for clinical application in routine renal examination.

METHODSForty volunteers (25 male and 15 female adults, aged 30 to 62 years) with normal renal function were included in this prospective study. All the subjects underwent 3.0 Tesla MR scanning using 3 MR scan modes, namely breath-holding EPI-FAIR, breath-holding SSFSE-FAIR and free breathing SSFSE-FAIR.

RESULTSSSFSE-FAIR without breath-holding was capable of differentiating the renal cortex and medulla with the corresponding rBFVs of 111.48∓9.23 and 94.98∓3.38, respectively. Breath-holding SSFSE-FAIR and EPI-FAIR failed to distinguish the borders of the renal cortex and medulla. The EPI-FAIR rBFV of mixed cortex and medulla value was 178.50∓17.17 (95%CI: 167.59, 189.41).

CONCLUSIONBreath-holding SSFSE-FAIR and EPI-FAIR can not distinguish the renal cortex and medulla due to a poor spatial resolution but can be used for rough evaluation of renal blood perfusion. Free breathing SSFSE-FAIR with an improved spatial resolution allows evaluation of the status of renal perfusion of the cortex and medulla.

Adult ; Echo-Planar Imaging ; methods ; Female ; Humans ; Kidney ; blood supply ; physiology ; Magnetic Resonance Imaging ; methods ; Male ; Middle Aged ; Prospective Studies ; Renal Circulation

OBJECTIVETo distinguish the edema, injury, or rupture in the traumatic skeletal muscle fiber in vivo using diffusion tensor imaging (DTI) and tractography on magnetic resonance imaging (MRI).

METHODSThe skeletal muscle trauma models were made in 4 rabbits (eight hindlimbs) by iron discus (weight 1.0 kg, diameter 6 cm) falling down vertically from 45 cm height to rabbits' thighs. Conventional sequences and two-dimensional (2D) diffusion-weighted (DW) spin-echo (SE) echo planar imaging (EPI) sequence with fat suppression (b = 600 s/mm2) were performed on 1. 5T MRI scanner. The grading of edema, injury, and fiber rupture in the damaged muscle were made according to their histopathological views, which was consistent with the images. The mean apparent diffusion coefficient (ADC) values and fractional anisotropy (FA) values were measured from the region of interests (ROIs) of all groups on 2D DW images used for tractography. Analysis of variance test was performed to analyze all data.

RESULTSADC values of the areas in normal muscle, edema muscle, injury muscle, and ruptured muscle were (6.12 +/- 1.34) x 10(-3), (6.38 +/- 1.30) x 10(-3), (8.06 +/- 0.97) x 10(-3), and (9.57 +/- 0.93) x 10(-3) mm2/s, respectively. There was significant difference among groups (P < 0.001), but no difference between edema muscle and normal muscle group (P > 0.05). The FA values of normal muscle, edema muscle, injury muscle, and ruptured muscle were 0.42 +/- 0.12, 0.36 +/- 0.12, 0.26 +/- 0.09, 0.12 +/- 0.08, respectively, with a significant difference among groups (P < 0.001). In the edema muscle, the tracking cross-fiber could be seen but it decreased slightly. In the injury muscle, the tracking fiber decreased markedly. In the ruptured muscle, the transverse-orientation tracking fiber vanished, yet some interrupted longitudinal-orientation tracking fiber could be found.

CONCLUSIONThe edema, injury, and rupture of muscle fiber in rabbit damaged skeletal muscle can be verified according to the ADC and the FA on DTI and tractography.

Animals ; Anisotropy ; Diffusion Magnetic Resonance Imaging ; methods ; Echo-Planar Imaging ; Edema ; diagnosis ; pathology ; Male ; Muscle, Skeletal ; injuries ; pathology ; Rabbits ; Rupture ; diagnosis ; pathology ; Thigh ; injuries ; pathology

OBJECTIVE: Understanding the neural functional organization of swallowing in the elderly is essential when diagnosing and treating older adults with swallowing difficulties. While brain-imaging studies in young adults have implicated multiple cortical regions in swallowing, only a few investigations were performed on older subjects. In this study, we aimed to compare neural activation in regions for swallowing between healthy young and older adults and to better understand neural control of deglutition, complex sensory-motor process which occurs as a result of old age. METHOD: Fifteen young and fifteen older healthy individuals without a swallowing problem were examined with functional magnetic resonance imaging (fMRI) during voluntary saliva swallowing. Functional image data was obtained with a T2 gradient-echo, echo planar imaging (EPI) pulse sequence optimized for blood-oxygen level dependent (BOLD) contrast. Two samples t-test was conducted to perform group comparison (younger adults versus older adults) for the areas in which the activation was larger for the swallowing condition than the non-swallow condition. RESULT: Both groups showed activations in areas involved in the motor control and execution. In both groups, main regions of activation included bilateral prefrontal cortex, primary somatosensory cortex, insula, basal ganglia, and cerebellum. Between-group comparisons revealed statistically stronger activations in the prefrontal cortex and middle temporal gyrus of older adults during swallowing. CONCLUSION: This study provides evidence that swallowing requires larger and more widespread areas of neural control in older adults group, especially in prefrontal cortex and inferior frontal gyrus. These findings suggest that more demanding swallowing tasks are necessary for elderly patients because of their inefficient neural network due to their age.
Adult ; Aged ; Basal Ganglia ; Cerebellum ; Deglutition* ; Echo-Planar Imaging ; Humans ; Magnetic Resonance Imaging* ; Methods ; Prefrontal Cortex ; Saliva ; Somatosensory Cortex ; Temporal Lobe ; Young Adult