共查询到20条相似文献,搜索用时 15 毫秒
1.
Daniel Paech Moritz Zaiss Jan-Eric Meissner Johannes Windschuh Benedikt Wiestler Peter Bachert Jan Oliver Neumann Philipp Kickingereder Heinz-Peter Schlemmer Wolfgang Wick Armin Michael Nagel Sabine Heiland Mark Edward Ladd Martin Bendszus Alexander Radbruch 《PloS one》2014,9(8)
Background and Purpose
Nuclear Overhauser Enhancement (NOE) mediated chemical exchange saturation transfer (CEST) is a novel magnetic resonance imaging (MRI) technique on the basis of saturation transfer between exchanging protons of tissue proteins and bulk water. The purpose of this study was to evaluate and compare the information provided by three dimensional NOE mediated CEST at 7 Tesla (7T) and standard MRI in glioblastoma patients.Patients and Methods
Twelve patients with newly diagnosed histologically proven glioblastoma were enrolled in this prospective ethics committee–approved study. NOE mediated CEST contrast was acquired with a modified three-dimensional gradient-echo sequence and asymmetry analysis was conducted at 3.3ppm (B1 = 0.7 µT) to calculate the magnetization transfer ratio asymmetry (MTRasym). Contrast enhanced T1 (CE-T1) and T2-weighted images were acquired at 3T and used for data co-registration and comparison.Results
Mean NOE mediated CEST signal based on MTRasym values over all patients was significantly increased (p<0.001) in CE-T1 tumor (−1.99±1.22%), tumor necrosis (−1.36±1.30%) and peritumoral CEST hyperintensities (PTCH) within T2 edema margins (−3.56±1.24%) compared to contralateral normal appearing white matter (−8.38±1.19%). In CE-T1 tumor (p = 0.015) and tumor necrosis (p<0.001) mean MTRasym values were significantly higher than in PTCH. Extent of the surrounding tumor hyperintensity was smaller in eight out of 12 patients on CEST than on T2-weighted images, while four displayed at equal size. In all patients, isolated high intensity regions (0.40±2.21%) displayed on CEST within the CE-T1 tumor that were not discernible on CE-T1 or T2-weighted images.Conclusion
NOE mediated CEST Imaging at 7T provides additional information on the structure of peritumoral hyperintensities in glioblastoma and displays isolated high intensity regions within the CE-T1 tumor that cannot be acquired on CE-T1 or T2-weighted images. Further research is needed to determine the origin of NOE mediated CEST and possible clinical applications such as therapy assessment or biopsy planning. 相似文献2.
Suvi Rautiainen Mervi K?n?nen Reijo Sironen Amro Masarwah Mazen Sudah Juhana Hakum?ki Ritva Vanninen Anna Sutela 《PloS one》2015,10(3)
The axillary staging in newly diagnosed breast cancer is under major evolution. The aims of this study were to define the diagnostic performance of 3.0-T diffusion-weighted imaging (DWI) in the detection of axillary metastases in newly diagnosed breast cancer, to assess apparent diffusion coefficients (ADCs) for histopathologically confirmed metastatic lymph nodes in a clinical setting. Altogether 52 consecutive breast cancer patients underwent magnetic resonance imaging and DWI in addition to axillary ultrasound. ADCs of axillary lymph nodes were analysed by two breast radiologists and ultrasound-guided core biopsies were taken. In a separate reading by one radiologist two types of region of interests were used for a smaller group of patients. Altogether 56 axillae (121 lymph nodes) were included in the statistical analysis. Metastatic axillae (51.8%) had significantly lower ADCs (p<0.001). Mean ADCs were 0.663–0.676 x 10-3 mm2/s for the histologically confirmed metastatic LNs and 1.100–1.225 x 10-3 mm2/s for the benign. The sensitivity, specificity, and accuracy of DWI were 72.4%, 79.6%, and 75.9%, respectively with threshold ADC 0.812 x 10-3 mm2/s. Region of interest with information on the minimum value increased the diagnostic performance (area under the curve 0.794 vs. 0.619). Even though ADCs are significantly associated with histopathologically confirmed axillary metastases the diagnostic performance of axillary DWI remains moderate and ultrasound-guided core biopsies or sentinel lymph node biopsies cannot be omitted. 相似文献
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Lihua Chen Min Liu Jing Bao Yunbao Xia Jiuquan Zhang Lin Zhang Xuequan Huang Jian Wang 《PloS one》2013,8(11)
Objective
To perform a meta-analysis exploring the correlation between the apparent diffusion coefficient (ADC) and tumor cellularity in patients.Materials and Methods
We searched medical and scientific literature databases for studies discussing the correlation between the ADC and tumor cellularity in patients. Only studies that were published in English or Chinese prior to November 2012 were considered for inclusion. Summary correlation coefficient (r) values were extracted from each study, and 95% confidence intervals (CIs) were calculated. Sensitivity and subgroup analyses were performed to investigate potential heterogeneity.Results
Of 189 studies, 28 were included in the meta-analysis, comprising 729 patients. The pooled r for all studies was −0.57 (95% CI: −0.62, −0.52), indicating notable heterogeneity (P<0.001). After the sensitivity analysis, two studies were excluded, and the pooled r was −0.61 (95% CI: −0.66, −0.56) and was not significantly heterogeneous (P = 0.127). Regarding tumor type subgroup analysis, there were sufficient data to support a strong negative correlation between the ADC and cellularity for brain tumors. There was no notable evidence of publication bias.Conclusions
There is a strong negative correlation between the ADC and tumor cellularity in patients, particularly in the brain. However, larger, prospective studies are warranted to validate these findings in other cancer types. 相似文献5.
Objective
Apparent diffusion coefficients (ADC) can help differentiate between central nervous system (CNS) lymphoma and Glioblastoma (GBM). However, overlap between ADCs for GBM and lymphoma have been reported because of various region of interest (ROI) methods. Our aim is to explore ROI method to provide the most reproducible results for differentiation.Materials and Methods
We studied 25 CNS lymphomas and 62 GBMs with three ROI methods: (1) ROI1, whole tumor volume; (2) ROI2, multiple ROIs; and (3) ROI3, a single ROI. Interobserver variability of two readers for each method was analyzed by intraclass correlation(ICC). ADCs were compared between GBM and lymphoma, using two-sample t-test. The discriminative ability was determined by ROC analysis.Results
ADCs from ROI1 showed most reproducible results (ICC >0.9). For ROI1, ADCmean for lymphoma showed significantly lower values than GBM (p = 0.03). The optimal cut-off value was 0.98×10−3 mm2/s with 85% sensitivity and 90% specificity. For ROI2, ADCmin for lymphoma was significantly lower than GBM (p = 0.02). The cut-off value was 0.69×10−3 mm2/s with 87% sensitivity and 88% specificity.Conclusion
ADC values were significantly dependent on ROI method. ADCs from the whole tumor volume had the most reproducible results. ADCmean from the whole tumor volume may aid in differentiating between lymphoma and GBM. However, multi-modal imaging approaches are recommended than ADC alone for differentiation. 相似文献6.
Madelaine Daianu Russell E. Jacobs Tara M. Weitz Terrence C. Town Paul M. Thompson 《PloS one》2015,10(12)
Diffusion weighted imaging (DWI) is widely used to study microstructural characteristics of the brain. Diffusion tensor imaging (DTI) and high-angular resolution imaging (HARDI) are frequently used in radiology and neuroscience research but can be limited in describing the signal behavior in composite nerve fiber structures. Here, we developed and assessed the benefit of a comprehensive diffusion encoding scheme, known as hybrid diffusion imaging (HYDI), composed of 300 DWI volumes acquired at 7-Tesla with diffusion weightings at b = 1000, 3000, 4000, 8000 and 12000 s/mm2 and applied it in transgenic Alzheimer rats (line TgF344-AD) that model the full clinico-pathological spectrum of the human disease. We studied and visualized the effects of the multiple concentric “shells” when computing three distinct anisotropy maps–fractional anisotropy (FA), generalized fractional anisotropy (GFA) and normalized quantitative anisotropy (NQA). We tested the added value of the multi-shell q-space sampling scheme, when reconstructing neural pathways using mathematical frameworks from DTI and q-ball imaging (QBI). We show a range of properties of HYDI, including lower apparent anisotropy when using high b-value shells in DTI-based reconstructions, and increases in apparent anisotropy in QBI-based reconstructions. Regardless of the reconstruction scheme, HYDI improves FA-, GFA- and NQA-aided tractography. HYDI may be valuable in human connectome projects and clinical research, as well as magnetic resonance research in experimental animals. 相似文献
7.
Karsten H. Wrede Philipp Dammann Christoph M?nninghoff S?ren Johst Stefan Maderwald I. Erol Sandalcioglu Oliver Müller Neriman ?zkan Mark E. Ladd Michael Forsting Marc U. Schlamann Ulrich Sure Lale Umutlu 《PloS one》2014,9(1)
Purpose
To prospectively evaluate 7 Tesla time-of-flight (TOF) magnetic resonance angiography (MRA) in comparison to 1.5 Tesla TOF MRA and 7 Tesla non-contrast enhanced magnetization-prepared rapid acquisition gradient-echo (MPRAGE) for delineation of unruptured intracranial aneurysms (UIA).Material and Methods
Sixteen neurosurgical patients (male n = 5, female n = 11) with single or multiple UIA were enrolled in this trial. All patients were accordingly examined at 7 Tesla and 1.5 Tesla MRI utilizing dedicated head coils. The following sequences were obtained: 7 Tesla TOF MRA, 1.5 Tesla TOF MRA and 7 Tesla non-contrast enhanced MPRAGE. Image analysis was performed by two radiologists with regard to delineation of aneurysm features (dome, neck, parent vessel), presence of artifacts, vessel-tissue-contrast and overall image quality. Interobserver accordance and intermethod comparisons were calculated by kappa coefficient and Lin''s concordance correlation coefficient.Results
A total of 20 intracranial aneurysms were detected in 16 patients, with two patients showing multiple aneurysms (n = 2, n = 4). Out of 20 intracranial aneurysms, 14 aneurysms were located in the anterior circulation and 6 aneurysms in the posterior circulation. 7 Tesla MPRAGE imaging was superior over 1.5 and 7 Tesla TOF MRA in the assessment of all considered aneurysm and image quality features (e.g. image quality: mean MPRAGE7T: 5.0; mean TOF7T: 4.3; mean TOF1.5T: 4.3). Ratings for 7 Tesla TOF MRA were equal or higher over 1.5 Tesla TOF MRA for all assessed features except for artifact delineation (mean TOF7T: 4.3; mean TOF1.5T 4.4). Interobserver accordance was good to excellent for most ratings.Conclusion
7 Tesla MPRAGE imaging demonstrated its superiority in the detection and assessment of UIA as well as overall imaging features, offering excellent interobserver accordance and highest scores for all ratings. Hence, it may bear the potential to serve as a high-quality diagnostic tool for pretherapeutic assessment and follow-up of untreated UIA. 相似文献8.
Alexander Radbruch Oliver Eidel Benedikt Wiestler Daniel Paech Sina Burth Philipp Kickingereder Martha Nowosielski Philipp B?umer Wolfgang Wick Heinz-Peter Schlemmer Martin Bendszus Mark Ladd Armin Michael Nagel Sabine Heiland 《PloS one》2014,9(11)
Purpose
To analyze if tumor vessels can be visualized, segmented and quantified in glioblastoma patients with time of flight (ToF) angiography at 7 Tesla and multiscale vessel enhancement filtering.Materials and Methods
Twelve patients with newly diagnosed glioblastoma were examined with ToF angiography (TR = 15 ms, TE = 4.8 ms, flip angle = 15°, FOV = 160×210 mm2, voxel size: 0.31×0.31×0.40 mm3) on a whole-body 7 T MR system. A volume of interest (VOI) was placed within the border of the contrast enhancing part on T1-weighted images of the glioblastoma and a reference VOI was placed in the non-affected contralateral white matter. Automated segmentation and quantification of vessels within the two VOIs was achieved using multiscale vessel enhancement filtering in ImageJ.Results
Tumor vessels were clearly visible in all patients. When comparing tumor and the reference VOI, total vessel surface (45.3±13.9 mm2 vs. 29.0±21.0 mm2 (p<0.035)) and number of branches (3.5±1.8 vs. 1.0±0.6 (p<0.001) per cubic centimeter were significantly higher, while mean vessel branch length was significantly lower (3.8±1.5 mm vs 7.2±2.8 mm (p<0.001)) in the tumor.Discussion
ToF angiography at 7-Tesla MRI enables characterization and quantification of the internal vascular morphology of glioblastoma and may be used for the evaluation of therapy response within future studies. 相似文献9.
Objective
To assess the added value of diffusion-weighted magnetic resonance imaging (DWI) with apparent diffusion coefficient (ADC) values compared to MRI, for characterizing the tubo-ovarian abscesses (TOA) mimicking ovarian malignancy.Materials and Methods
Patients with TOA (or ovarian abscess alone; n = 34) or ovarian malignancy (n = 35) who underwent DWI and MRI were retrospectively reviewed. The signal intensity of cystic and solid component of TOAs and ovarian malignant tumors on DWI and the corresponding ADC values were evaluated, as well as clinical characteristics, morphological features, MRI findings were comparatively analyzed. Receiver operating characteristic (ROC) curve analysis based on logistic regression was applied to identify different imaging characteristics between the two patient groups and assess the predictive value of combination diagnosis with area under the curve (AUC) analysis.Results
The mean ADC value of the cystic component in TOA was significantly lower than in malignant tumors (1.04 ± 0 .41 × 10−3 mm2/s vs. 2.42 ± 0.38 × 10−3 mm2/s; p < 0.001). The mean ADC value of the enhanced solid component in 26 TOAs was 1.43 ± 0.16×10−3mm2/s, and 46.2% (12 TOAs; pseudotumor areas) showed significantly higher signal intensity on DW-MRI than in ovarian malignancy (mean ADC value 1.44 ± 0.20×10−3 mm2/s vs.1.18 ± 0.36 × 10−3 mm2/s; p = 0.043). The combination diagnosis of ADC value and dilated tubal structure achieved the best AUC of 0.996. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of MRI vs. DWI with ADC values for predicting TOA were 47.1%, 91.4%, 84.2%, 64%, and 69.6% vs. 100%, 97.1%, 97.1%, 100%, and 98.6%, respectively.Conclusions
DW-MRI is superior to MRI in the assessment of TOA mimicking ovarian malignancy, and the ADC values aid in discriminating the pseudotumor area of TOA from the solid portion of ovarian malignancy. 相似文献10.
Stefanie Kirschner Bettina Mürle Manuela Felix Anna Arns Christoph Groden Frederik Wenz Andreas Hug Gerhard Glatting Martin Kramer Frank A. Giordano Marc A. Brockmann 《PloS one》2016,11(11)
PurposeThere is an increasing need for small animal in vivo imaging in murine orthotopic glioma models. Because dedicated small animal scanners are not available ubiquitously, the applicability of a clinical CT scanner for visualization and measurement of intracerebrally growing glioma xenografts in living mice was validated.ResultsTumor volumes (mean±SD mm3) were similar between both CT-modalities (micro-CT: 19.8±19.0, clinical CT: 19.8±18.8; Wilcoxon signed-rank test p = 0.813). Moreover, between reader analyses for each modality showed excellent agreement as demonstrated by correlation analysis (Spearman-Rho >0.9; p<0.01 for all correlations). Histologically measured tumor volumes (11.0±11.2) were significantly smaller due to shrinkage artifacts (p<0.05). CNR and SNR were 2.1±1.0 and 1.1±0.04 for micro-CT and 23.1±24.0 and 1.9±0.7 for the clinical CTscanner, respectively.ConclusionClinical CT scanners may reliably be used for in vivo imaging and volumetric analysis of brain tumor growth in mice. 相似文献
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Objective
We elected to analyze the correlation between the pre-treatment apparent diffusion coefficient (ADC) and the clinical, histological, and immunohistochemical status of rectal cancers.Materials and Methods
Forty-nine rectal cancer patients who received surgical resection without neoadjuvant therapy were selected that underwent primary MRI and diffusion-weighted imaging (DWI). Tumor ADC values were determined and analyzed to identify any correlations between these values and pre-treatment CEA or CA19-9 levels, and/or the histological and immunohistochemical properties of the tumor.Results
Inter-observer agreement of confidence levels from two separate observers was suitable for ADC measurement (k = 0.775). The pre-treatment ADC values of different T stage tumors were not equal (p = 0.003). The overall trend was that higher T stage values correlated with lower ADC values. ADC values were also significantly lower for the following conditions: tumors with the presence of extranodal tumor deposits (p = 0.006) and tumors with CA19-9 levels ≥ 35 g/ml (p = 0.006). There was a negative correlation between Ki-67 LI and the ADC value (r = −0.318, p = 0.026) and between the AgNOR count and the ADC value (r = −0.310, p = 0.030).Conclusion
Significant correlations were found between the pre-treatment ADC values and T stage, extranodal tumor deposits, CA19-9 levels, Ki-67 LI, and AgNOR counts in our study. Lower ADC values were associated with more aggressive tumor behavior. Therefore, the ADC value may represent a useful biomarker for assessing the biological features and possible relationship to the status of identified rectal cancers. 相似文献12.
ObjectiveTo evaluate the predictive value of the apparent diffusion coefficient (ADC) for pathologic complete response (pCR) to neoadjuvant chemoradiotherapy (NCRT) in locally advanced rectal cancer.MethodsA total of 265 patients with rectal adenocarcinoma, whole Diffusion-Weighted MRI (DWI-MRI) images, clinically stage II to III (cT3-4 and/or cN+) and treated with NCRT followed by TME were screened. Fifty patients with pCR and another 50 patients without pCR with similar clinical charcacters and treatment regimens were selected for statistical analysis. All the patients’ pre-CRT and post-CRT average ADC values were calculated from the coefficient maps created by DWI-MRI and recorded independently. The difference in the ADC values between the pCR and non-pCR was analyzed by the Mann-Whitney U test. The cut-off ADC value of the receiver operating characteristic (ROC) curve with pCR was then established.ResultsThe mean pre- and post-ADC values in all patients, and in pCR patients and non-pCR patients were 0.879±0.06 and 1.383±0.11, 0.859±0.04 and 1.440±0.10, 0.899±0.07 and 1.325±0.09 (×10-3mm2/s), respectively. The difference between the pre- and post-ADC values in all patients, pCR patients, and non-pCR patients were considered to be statistically significant. The pre-ADC value was significantly lower in the pCR patients than in the non-pCR patients (p = 0.003), whereas the post-ADC values were significantly higher in the pCR patients than in the non-pCR patients. The percentage increase of the ADC value (ΔADC%) in the pCR and non-pCR patients were 68% and 48% respectively (p<0.001). The ROC curves of the cut-off value of the pre-CRT patient ADC value was 0.866×10-3mm2/s. The AUC, sensitivity, specificity, PPV, NPV, and accuracy of diagnosing pCR were 0.670 (95% CI 0.563–0.777), 0.600, 0.640, 60%, 60%, and 60%, respectively. The cut-off value of ΔADC% was 58%. The corresponding AUC, sensitivity, specificity, PPV, NPV, and accuracy of diagnosing pCR were 0.856 (95% CI 0.783–0.930), 0.800, 0.760, 76.9%, 79.2%, and 78%, respectively.ConclusionsDWI-MRI technology can be efficient for predicting pCR for LARC after NCRT. Although the mean pre-CRT ADC value and the ΔADC% are moderate predictors for pCR, the latter would be more accurate. 相似文献
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Johannes Grueneisen Karsten Beiderwellen Philipp Heusch Paul Buderath Bahriye Aktas Marcel Gratz Michael Forsting Thomas Lauenstein Verena Ruhlmann Lale Umutlu 《PloS one》2014,9(5)
Background
To evaluate a potential correlation of the maximum standard uptake value (SUVmax) and the minimum apparent diffusion coefficient (ADCmin) in primary and recurrent cervical cancer based on integrated PET/MRI examinations.Methods
19 consecutive patients (mean age 51.6 years; range 30–72 years) with histopathologically confirmed primary cervical cancer (n = 9) or suspected tumor recurrence (n = 10) were prospectively enrolled for an integrated PET/MRI examination. Two radiologists performed a consensus reading in random order, using a dedicated post-processing software. Polygonal regions of interest (ROI) covering the entire tumor lesions were drawn into PET/MR images to assess SUVmax and into ADC parameter maps to determine ADCmin values. Pearson’s correlation coefficients were calculated to assess a potential correlation between the mean values of ADCmin and SUVmax.Results
In 15 out of 19 patients cervical cancer lesions (n = 12) or lymph node metastases (n = 42) were detected. Mean SUVmax (12.5±6.5) and ADCmin (644.5±179.7×10−5 mm2/s) values for all assessed tumor lesions showed a significant but weak inverse correlation (R = −0.342, p<0.05). When subdivided in primary and recurrent tumors, primary tumors and associated primary lymph node metastases revealed a significant and strong inverse correlation between SUVmax and ADCmin (R = −0.692, p<0.001), whereas recurrent cancer lesions did not show a significant correlation.Conclusions
These initial results of this emerging hybrid imaging technique demonstrate the high diagnostic potential of simultaneous PET/MR imaging for the assessment of functional biomarkers, revealing a significant and strong correlation of tumor metabolism and higher cellularity in cervical cancer lesions. 相似文献14.
目的:探讨磁共振成像(MRI)表观扩散系数(ADC)与乳腺浸润性导管癌组织学分级及其预后指标的相关性。方法:收集2016年5月至2017年5月于我院就诊的并经手术病理确诊为乳腺浸润性导管癌的患者112例作为研究对象,选取患者乳腺癌组织样本作为病例组,同时选取患者对侧正常乳腺组织样本作为对照组,所有患者均行常规MRI和磁共振扩散加权成像(DW-MRI)检查,分别测量两组样本的ADC值,比较不同乳腺浸润性导管癌组织学分级与正常乳腺组织的ADC值,分析乳腺浸润性导管癌组织的ADC值与肿瘤直径大小、淋巴结转移状态、有无远处转移及雌激素受体(ER)、孕激素受体(PR)和Ki-67表达的关系,并分析ADC值与组织学分级及预后指标的相关性。结果:乳腺浸润性导管癌病理分级I级的ADC值低于对照组,病理分级II级的ADC值低于病理分级I级及对照组,病理分级III级的ADC值低于病理分级II级、I级及对照组,差异均具有统计学意义(P0.05)。乳腺浸润性导管癌患者中,肿块直径2 cm、无淋巴结转移、ER阴性、PR阴性、Ki-67阴性患者的平均ADC值均高于肿块直径≥2 cm、有淋巴结转移、ER阳性、PR阳性、Ki-67阳性患者,差异均具有统计学意义(P0.05);而有无远处转移患者之间比较差异无统计学意义(P0.05)。经Spearman秩相关分析结果显示,乳腺浸润性导管癌患者的ADC值与病理组织学分级呈现负相关关系(rs=-0.716,P=0.000);与肿块直径大小、有无淋巴结转移及ER、PR、Ki-67的表达均呈负相关(rs=-0.316、-0.545、-0.667、-0.598、-0.443,P均0.05),与有无远处转移无相关性(rs=0.091,P=0.887)。结论:乳腺浸润性导管癌的ADC值与癌组织学分级和预后相关指标存在一定相关性,可作为一种临床诊断和判断预后的重要指标,具有重要临床价值。 相似文献
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Melissa A. Batson Natalia Petridou Dennis W. J. Klomp Maarten A. Frens Sebastiaan F. W. Neggers 《PloS one》2015,10(8)
The recent increase in the use of high field MR systems is accompanied by a demand for acquisition techniques and coil systems that can take advantage of increased power and accuracy without being susceptible to increased noise. Physical location and anatomical complexity of targeted regions must be considered when attempting to image deeper structures with small nuclei and/or complex cytoarchitechtonics (i.e. small microvasculature and deep nuclei), such as the brainstem and the cerebellum (Cb). Once these obstacles are overcome, the concomitant increase in signal strength at higher field strength should allow for faster acquisition of MR images. Here we show that it is technically feasible to quickly and accurately detect blood oxygen level dependent (BOLD) signal changes and obtain anatomical images of Cb at high spatial resolutions in individual subjects at 7 Tesla in a single one-hour session. Images were obtained using two high-density multi-element surface coils (32 channels in total) placed beneath the head at the level of Cb, two channel transmission, and three-dimensional sensitivity encoded (3D, SENSE) acquisitions to investigate sensorimotor activations in Cb. Two classic sensorimotor tasks were used to detect Cb activations. BOLD signal changes during motor activity resulted in concentrated clusters of activity within the Cb lobules associated with each task, observed consistently and independently in each subject: Oculomotor vermis (VI/VII) and CrusI/II for pro- and anti-saccades; ipsilateral hemispheres IV-VI for finger tapping; and topographical separation of eye- and hand- activations in hemispheres VI and VIIb/VIII. Though fast temporal resolution was not attempted here, these functional patches of highly specific BOLD signal changes may reflect small-scale shunting of blood in the microvasculature of Cb. The observed improvements in acquisition time and signal detection are ideal for individualized investigations such as differentiation of functional zones prior to surgery. 相似文献
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Alexey Surov Daniel T Ginat Tchoyoson Lim Teresa Cabada Ozdil Baskan Stefan Schob Hans Jonas Meyer Georg Alexander Gihr Diana Horvath-Rizea Gordian Hamerla Karl Titus Hoffmann Andreas Wienke 《Translational oncology》2018,11(5):1074-1079
Low grade meningiomas have better prognosis than high grade meningiomas. The aim of this study was to measure apparent diffusion coefficient (ADC) histogram analysis parameters in different meningiomas in a large multicenter sample and to analyze the possibility of several parameters for predicting tumor grade and proliferation potential. Overall, 148 meningiomas from 7 institutions were evaluated in this retrospective study. Grade 1 lesions were diagnosed in 101 (68.2%) cases, grade 2 in 41 (27.7%) patients, and grade 3 in 6 (4.1%) patients. All tumors were investigated by MRI (1.5 T scanner) by using diffusion weighted imaging (b values of 0 and 1000 s/mm2). For every lesion, the following parameters were calculated: mean ADC, maximum ADC, minimum ADC, median ADC, mode ADC, ADC percentiles P10, P25, P75, P90, kurtosis, skewness, and entropy. The comparison of ADC values was performed by Mann–Whitney-U test. Correlation between different ADC parameters and KI 67 was calculated by Spearman's rank correlation coefficient. Grade 2/3 meningiomas showed statistically significant lower ADC histogram analysis parameters in comparison to grade 1 tumors, especially ADC median. A threshold value of 0.82 for ADC median to predict tumor grade was estimated (sensitivity?=?82.2%, specificity?=?63.8%, accuracy?=?76.4%, positive and negative predictive values were 83% and 62.5%, respectively).All ADC parameters except maximum ADC showed weak significant correlations with KI 67, especially ADC P25 (P?=??.340, P?=?.0001). 相似文献
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Tim Herrmann Johannes Mallow Markus Plaumann Michael Luchtmann J?rg Stadler Judith Mylius Michael Brosch Johannes Bernarding 《PloS one》2015,10(6)
Introduction
Neuroimaging of macaques at ultra-high field (UHF) is usually conducted by combining a volume coil for transmit (Tx) and a phased array coil for receive (Rx) tightly enclosing the monkey’s head. Good results have been achieved using vertical or horizontal magnets with implanted or near-surface coils. An alternative and less costly approach, the travelling-wave (TW) excitation concept, may offer more flexible experimental setups on human whole-body UHF magnetic resonance imaging (MRI) systems, which are now more widely available. Goal of the study was developing and validating the TW concept for in vivo primate MRI.Methods
The TW Primate System (TWPS) uses the radio frequency shield of the gradient system of a human whole-body 7 T MRI system as a waveguide to propagate a circularly polarized B1 field represented by the TE11 mode. This mode is excited by a specifically designed 2-port patch antenna. For receive, a customized neuroimaging monkey head receive-only coil was designed. Field simulation was used for development and evaluation. Signal-to-noise ratio (SNR) was compared with data acquired with a conventional monkey volume head coil consisting of a homogeneous transmit coil and a 12-element receive coil.Results
The TWPS offered good image homogeneity in the volume-of-interest Turbo spin echo images exhibited a high contrast, allowing a clear depiction of the cerebral anatomy. As a prerequisite for functional MRI, whole brain ultrafast echo planar images were successfully acquired.Conclusion
The TWPS presents a promising new approach to fMRI of macaques for research groups with access to a horizontal UHF MRI system. 相似文献19.
Chun-Jung Juan Cheng-Chieh Cheng Su-Chin Chiu Yee-Min Jen Yi-Jui Liu Hui-Chu Chiu Hung-Wen Kao Chih-Wei Wang Hsiao-Wen Chung Guo-Shu Huang Hsian-He Hsu 《PloS one》2015,10(8)
Purpose
To concurrently quantify the radiation-induced changes and temporal evolutions of parotid volume and parotid apparent diffusion coefficient (ADC) in nasopharyngeal carcinoma (NPC) patients treated by intensity-modulated radiotherapy by using magnetic resonance imaging (MRI).Materials and Methods
A total of 11 NPC patients (9 men and 2 women; 48.7 ± 11.7 years, 22 parotid glands) were enrolled. Radiation dose, parotid sparing volume, severity of xerostomia, and radiation-to-MR interval (RMI) was recorded. MRI studies were acquired four times, including one before and three after radiotherapy. The parotid volume and the parotid ADC were measured. Statistical analysis was performed using SPSS and MedCalc. Bonferroni correction was applied for multiple comparisons. A P value less than 0.05 was considered as statistically significant.Results
The parotid volume was 26.2 ± 8.0 cm3 before radiotherapy. The parotid ADC was 0.8 ± 0.15 × 10−3 mm2/sec before radiotherapy. The parotid glands received a radiation dose of 28.7 ± 4.1 Gy and a PSV of 44.1 ± 12.6%. The parotid volume was significantly smaller at MR stage 1 and stage 2 as compared to pre-RT stage (P < .005). The volume reduction ratio was 31.2 ± 13.0%, 26.1 ± 13.5%, and 17.1 ± 16.6% at stage 1, 2, and 3, respectively. The parotid ADC was significantly higher at all post-RT stages as compared to pre-RT stage reciprocally (P < .005 at stage 1 and 2, P < .05 at stage 3). The ADC increase ratio was 35.7 ± 17.4%, 27.0 ± 12.8%, and 20.2 ± 16.6% at stage 1, 2, and 3, respectively. The parotid ADC was negatively correlated to the parotid volume (R = -0.509; P < .001). The parotid ADC was positively associated with the radiation dose significantly (R2 = 0.212; P = .0001) and was negatively associated with RMI significantly (R2 = 0.203; P = .00096) significantly. Multiple regression analysis further showed that the post-RT parotid ADC was related to the radiation dose and RMI significantly (R2 = 0.3580; P < .0001). At MR stage 3, the parotid volume was negatively associated with the dry mouth grade significantly (R2 = 0.473; P < .0001), while the parotid ADC was positively associated with the dry mouth grade significantly (R2 = 0.288; P = .015).Conclusion
Our pilot study successfully demonstrates the concurrent changes and temporal evolution of parotid volume and parotid ADC quantitatively in NPC patients treated by IMRT. Our results suggest that the reduction of parotid volume and increase of parotid ADC are dominated by the effect of acinar loss rather than edema at early to intermediate phases and the following recovery of parotid volume and ADC toward the baseline values might reflect the acinar regeneration of parotid glands. 相似文献20.
Laura Tiemann Jutta Hubertina Reidt Lorena Esposito Dirk Sander Wolfram Theiss Holger Poppert 《PloS one》2009,4(9)