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Becker V von Delius S Bajbouj M Karagianni A Schmid RM Meining A 《Gastrointestinal endoscopy》2008,68(2):319-323
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目的评价一种新型口服对比剂——茶叶(日照绿茶)为原料研制的磁共振口服阴性对比剂在腹部MRCP诊断中的价值和可行性,为临床MRCP检查应用提供一种理想对比剂,以进一步促进MRCP检查的发展。方法以水为参照物,将不同浓度的茶对比剂置于磁共振中进行同一序列的扫描,比较不同浓度的茶对比剂对成像信号的影响。在相同情况下选择17例志愿者对口服茶对比剂前后进行MRCP成像,对检查结果进行分析、综合。结果不同浓度的茶对比剂产生不同的信号,清晰度不同,经体外试验确定最佳浓度的茶中,锰的浓度为12.04±0.22mg/L。此浓度下的茶对比剂,信号与水相反,即T1高信号,T2低信号。MRCP成像抑制了胃、十二指肠道内的液体高信号,使胰胆管周围背号干净,突出胰胆管内的液体高信号成分,图像质量显著性提高(p〈0.05)。结论茶作为天然饮品,服用后安全,无毒副作用,对胃肠道无刺激,在肠腔内不发酵,不产生气体,充盈肠腔充分,保证肠腔内信号均匀一致。利用茶叶中锰的特性将茶作为磁共振MRCP检查口服阴性对比剂,不需要经过药物试验即可应用。在MRCP检查中应是一种理想的口服对比剂。 相似文献
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Midori Nakajima Simeon Wong Elysa Widjaja Shiro Baba Tohru Okanishi Lynne Takada Yosuke Sato Hiroki Iwata Maya Sogabe Hikaru Morooka Robyn Whitney Yuki Ueda Tomoshiro Ito Kazuyori Yagyu Ayako Ochi O. Carter Snead James T. Rutka James M. Drake Hiroshi Otsubo 《Clinical neurophysiology》2018,129(6):1182-1191
Objective
To investigate whether advanced dynamic statistical parametric mapping (AdSPM) using magnetoencephalography (MEG) can better localize focal cortical dysplasia at bottom of sulcus (FCDB).Methods
We analyzed 15 children with diagnosis of FCDB in surgical specimen and 3?T MRI by using MEG. Using AdSPM, we analyzed a ±50?ms epoch relative to each single moving dipole (SMD) and applied summation technique to estimate the source activity. The most active area in AdSPM was defined as the location of AdSPM spike source. We compared spatial congruence between MRI-visible FCDB and (1) dipole cluster in SMD method; and (2) AdSPM spike source.Results
AdSPM localized FCDB in 12 (80%) of 15 children whereas dipole cluster localized six (40%). AdSPM spike source was concordant within seizure onset zone in nine (82%) of 11 children with intracranial video EEG. Eleven children with resective surgery achieved seizure freedom with follow-up period of 1.9?±?1.5?years. Ten (91%) of them had an AdSPM spike source in the resection area.Conclusion
AdSPM can noninvasively and neurophysiologically localize epileptogenic FCDB, whether it overlaps with the dipole cluster or not.Significance
This is the first study to localize epileptogenic FCDB using MEG. 相似文献57.
Simon S. Martin Julian L. Wichmann Jan-Erik Scholtz Doris Leithner Tommaso D’Angelo Hendrik Weyer Christian Booz Lukas Lenga Thomas J. Vogl Moritz H. Albrecht 《Journal of vascular and interventional radiology : JVIR》2017,28(9):1257-1266
Purpose
To evaluate diagnostic accuracy of a noise-optimized virtual monoenergetic imaging (VMI+) reconstruction technique for detection of active arterial abdominal bleeding on dual-energy (DE) CT angiography compared with standard image reconstruction.Materials and Methods
DE CT angiography data sets of 71 patients (46 men; age 63.6 y ± 13.3) with suspected arterial bleeding of the abdomen or pelvis were reconstructed with standard linearly blended (F_0.5), VMI+, and traditional virtual monoenergetic imaging (VMI) algorithms in 10-keV increments from 40 to 100 keV. Attenuation measurements were performed in the descending aorta, area of hemorrhage, and feeding artery to calculate contrast-to-noise ratios (CNRs) in patients with active arterial bleeding. Based on quantitative image quality results, the best series for each reconstruction technique were chosen to analyze the diagnostic performance of 3 blinded radiologists.Results
DE CT angiography showed acute arterial bleeding in 36 patients. Mean CNR was superior in 40-keV VMI+ compared with VMI series (all P < .001), which showed highest CNRs in 70-keV VMI and F_0.5 (21.6 ± 7.9, 12.9 ± 4.7, and 10.4 ± 3.6) images. Area under the curve analysis for detection of arterial bleeding showed significantly superior (P < .001) results for 40-keV VMI+ (0.963) compared with 70-keV VMI (0.775) and F_0.5 (0.817) series.Conclusions
Diagnostic accuracy in patients with active arterial bleeding of the abdomen can be significantly improved using VMI+ reconstructions at 40 keV compared with standard linearly blended and traditional VMI series in DE CT angiography. 相似文献58.
Takanori Hara Katsuhiro Ichikawa Shigeru Sanada Yoshihiro Ida 《European journal of radiology》2010,75(1):114-121
Objective
The present study was performed to examine the dependence of image quality on in-plane position and direction in computed tomography (CT) imaging using the modulation transfer function (MTF), noise power spectrum (NPS) and analysis of signal-to-noise ratio (SNR). For detailed analysis of SNR, the low-contrast detectability was compared using simulated small low-contrast objects.Materials and methods
Three models of multidetector-row CT (MDCT) were employed. The measurement positions for MTF were set to the isocentre and several peripheral areas, and NPS and SNR were calculated for the isocentre and 128 mm off-centre. To evaluate directional dependence, the one-dimensional physical properties were measured separately in the radial and azimuthal directions. Seven radiological technologists also performed a perceptual detection study at the different in-plane positions using computer-simulated low-contrast images.Results
The results of MTF and SNR differed between the isocentre and the peripheral area. The MTF values also tended to decrease with distance from the isocentre, and the SNR values in the low frequency range for the peripheral area were superior to those for the isocentre. In the detection study, the low-contrast detectability in the peripheral area was 13-40% higher than the value in the isocentre.Conclusion
The results of the present study indicated that clinical CT images have remarkable non-uniformity of image quality. Therefore, the detailed analysis performed in this study will provide useful information for the development of advanced image processing applications, such as computer-aided diagnosis (CAD) and de-noising of CT images. 相似文献59.
Helen Marshall PhD Patrick M. Devine MSc Nishanthan Shanmugaratnam BEng Ryan Fobel MSc Peter Siegler PhD Cameron A. Piron MSc Donald B. Plewes PhD 《Journal of magnetic resonance imaging : JMRI》2010,31(2):328-338
Purpose:
To evaluate three multicoil breast arrays for both conventional and SENSE‐accelerated imaging.Materials and Methods:
Two commercially available 8‐element coils and a prototype 16‐element coil were compared. One 8‐element array had adjustable coils located next to the breast tissue and the other had a fixed coil arrangement; both were designed to allow parallel imaging in the left–right direction. The 16‐element coil was designed to have coil sensitivity variation in both the left–right and superior–inferior directions, and also had adjustable coils. Their performance was assessed in terms of signal‐to‐noise ratio (SNR), g‐factor, and uniformity with a custom‐built phantom.Results:
The 16‐element array with adjustable coils provided the highest SNR, while the 8‐element coil with a fixed coil arrangement had the best uniformity. All coils performed well for SENSE acceleration in the left–right direction. The 8‐element coils did not have the capability for acceleration in the superior–inferior direction across the whole volume. The 16‐element coil enabled acceleration in the superior–inferior direction in addition to the left–right direction.Conclusion:
Smaller, adjustable coil elements located next to breast tissue can provide greater SNR than larger, fixed coil elements. A multicoil breast array with high intrinsic SNR and low g‐factors enables high‐quality parallel imaging. J. Magn. Reson. Imaging 2010; 31: 328–338. © 2010 Wiley‐Liss, Inc. 相似文献60.