Objective The aim of the study was to use dynamic magnetic resonance imaging （MRI） to compare quantitative parameters of small bowel motility between healthy volunteers and patients with small bowel diseases in orde...Objective The aim of the study was to use dynamic magnetic resonance imaging （MRI） to compare quantitative parameters of small bowel motility between healthy volunteers and patients with small bowel diseases in order to investigate the characteristics of normal and impaired bowel peristalsis. Methods A total of 44 healthy volunteers （20 men, 24 women; mean age： 36 years; range： 20-61 years） and 42 patients （28 men, 14 women; mean age： 44 years; range： 15-72 years） with organic small bowel disease were recruited in our hospital （Tongji Hospital, Tongji Medical College, Huazhong University of Sci- ence and Technology, Wuhan, China） in this prospective study approved by the hospital institutional review board. Imaging was performed using a 3.0-T scanner 45 minutes after standardized oral administration of 1500 mL non-absorbable fluid （2.5% mannitol）. A serial coronal scan was performed at selected planes for two minutes without breath-hold. Time-caliber curves were plotted at two well-distended small bowel loops in both healthy and patient groups regardless of location. Luminal diameter （LD）, contraction period （CP）, frequency of contraction （FC）, and amplitude-diameter ratio （ADR） were measured based on the graph. Results The characteristics of abnormal peristaltic parameters were assessed in different patients and compared to normal curves from healthy volunteers. A total of 37 segments with abnormal motility were confirmed by two readers in consensus, based on curve patterns and the presence of a stationary phase. Compared to normal peristalsis in healthy volunteers, five different patterns of impaired peristalsis were identified： Ⅰ, consecutive; Ⅱ, slow; Ⅲ, giant type; Ⅳ, uncoordinated; and V, akinetic. Dilated LDs were de- tected in all instances of abnormal peristalsis （P 〈 0.05）. Increased frequency was found in type Ⅰ [（8.73 ± 1.15）/min], while decreased frequency was detected in type Ⅲ peristalsis [（0.67 ± 0.29）/min]. There were no significant differences in frequency between type Ⅱ [（3.19 ±0.43）/min] and normal peristalsis [（3.45± 0.57）/min]. Apart from typeⅠ [（8.70± 0.75）/min], increased FCs were found in all other abnormal patterns. In type Ⅱ peristalsis, the average ADR value was 0.82 ± 0.08, comparable to the ADR value in the healthy group （0.83 ± 0.13）. Conclusion MR cine is an effective method for differentiating normal and abnormal small bowel peristal- sis. Plotting time-caliber curves and measuring quantitative MR cine parameters such as LD, CP, FC, and ADR offers more precise information about small bowel motility.展开更多
Thunderstorms of pre-monsoon season (April – May) over Kolkata (22° 32’N, 88° 20’E), India are invariably accompanied with lightning flashes, high wind gusts, torrential rainfall, occasional hail and torn...Thunderstorms of pre-monsoon season (April – May) over Kolkata (22° 32’N, 88° 20’E), India are invariably accompanied with lightning flashes, high wind gusts, torrential rainfall, occasional hail and tornadoes which significantly affect the life and property on the ground and aviation aloft. The societal and economic impact due to such storms made accurate prediction of the weather phenomenon a serious concern for the meteorologists of India. The initiation of such storms requires sufficient moisture in lower troposphere, high surface temperature, conditional instability and a source of lift to initiate the convection. Convective available potential energy (CAPE) is a measure of the energy realized when conditional instability is released. It plays an important role in meso-scale convective systems. Convective inhibition energy (CINE) on the other hand acts as a possible barrier to the release of convection even in the presence of high value of CAPE. The main idea of the present study is to see whether a consistent quantitative range of CAPE and CINE can be identified for the prevalence of such thunderstorms that may aid in operational forecast. A statistical – fuzzy coupled method is implemented for the purpose. The result reveals that a definite range of CINE within 0 – 150 Jkg-1 is reasonably pertinent whereas no such range of CAPE depicts any consistency for the occurrence of severe thunderstorms over Kolkata. The measure of CINE mainly depends upon the altitude of the level of free convection (LFC), surface temperature (T) and surface mixing ratio (q). The box-and-whisker plot of LFC, T and q are drawn to select the most dependable parameter for the consistency of CINE in the prevalence of such thunderstorms. The skills of the parameters are evaluated through skill score analyses. The percentage error during validation with the observation of 2010 is estimated to be 0% for the range of CINE and 3.9% for CAPE.展开更多
Conventional multiple breath-hold two-dimensional （2D） balanced steady-state free precession （SSFP） presents many difficulties in cardiac cine magnetic resonance imaging （MRI）. Recently, a self-gated free-breath...Conventional multiple breath-hold two-dimensional （2D） balanced steady-state free precession （SSFP） presents many difficulties in cardiac cine magnetic resonance imaging （MRI）. Recently, a self-gated free-breathing three-dimensional （3D） SSFP technique has been proposed as an alternative in many studies. However, the accuracy and effectiveness of selfgating signals have been barely studied before. Since self-gating signals are crucially important in image reconstruction, a systematic study of self-gating signals and comparison with external monitored signals are needed. Previously developed self-gated free-breathing 3D SSFP techniques are used on twenty-eight healthy volunteers. Both electrocardiographic （ECG） and respiratory bellow signals are also acquired during the scan as external signals. Self-gating signal and external signal are compared by trigger and gating window. Gating window is proposed to evaluate the accuracy and effectiveness of respiratory self-gating signal. Relative deviation of the trigger and root-mean-square-deviation of the cycle duration are calculated. A two-tailed paired t-test is used to identify the difference between self-gating and external signals. A Wilcoxon signed rank test is used to identify the difference between peak and valley self-gating triggers. The results demonstrate an excellent correlation （P = 0, R 〉 0.99） between self-gating and external triggers. Wilcoxon signed rank test shows that there is no significant difference between peak and valley self-gating triggers for both cardiac （H = 0, P 〉 0.10） and respiratory （H = 0, P 〉 0.44） motions. The difference between self-gating and externally monitored signals is not significant （two-tailed paired-sample t-test： H = 0, P 〉 0.90）. The self-gating signals could demonstrate cardiac and respiratory motion accurately and effectively as ECG and respiratory bellow. The difference between the two methods is not significant and can be explained. Furthermore, few ECG trigger errors appear in some subjects while these errors are not found in self-gating signals.展开更多
9月22日,索尼中国专业系统集团在北京AIT索尼影像技术学院隆重举行Cine Alta V电影摄影机发布会,作为索尼Cine Alta摄影机系统的新一代产品,同时也是影视行业的第一款采用全画幅CMOS（36.2×24.1mm）的摄影机,Cine Alta V面世的消息...9月22日,索尼中国专业系统集团在北京AIT索尼影像技术学院隆重举行Cine Alta V电影摄影机发布会,作为索尼Cine Alta摄影机系统的新一代产品,同时也是影视行业的第一款采用全画幅CMOS（36.2×24.1mm）的摄影机,Cine Alta V面世的消息自9月发布以来便引发了影视行业用户持续的关注和讨论。发布会上,索尼专家和产品经理详解其性能优势、研发背景和多项突破性的＂业界第一＂,并与媒体、业界用户以现场问答、网络直播的方式进行互动,力求全面、精确、展开更多
This paper presents a nonlinear profile order scheme for three-dimensional（3D） hybrid radial acquisition applied to self-gated, free-breathing cardiac cine magnetic resonance imaging（MRI）. In self-gated, free-brea...This paper presents a nonlinear profile order scheme for three-dimensional（3D） hybrid radial acquisition applied to self-gated, free-breathing cardiac cine magnetic resonance imaging（MRI）. In self-gated, free-breathing cardiac cine MRI,respiratory and cardiac motions are unpredictable during acquisition, especially for retrospective reconstruction. Therefore,the non-uniformity of the k-space distribution is an issue of great concern during retrospective self-gated reconstruction. A nonlinear profile order with varying azimuthal increments was provided and compared with the existing golden ratio-based profile order. Optimal parameter values for the nonlinear formula were chosen based on simulations. The two profile orders were compared in terms of the k-space distribution and phantom and human image results. An approximately uniform distribution was obtained based on the nonlinear profile order for persons with various heart rates and breathing patterns.The nonlinear profile order provides more stable profile distributions and fewer streaking artifacts in phantom images. In a comparison of human cardiac cine images, the nonlinear profile order provided results comparable to those provided by the golden ratio-based profile order, and the images were suitable for diagnosis. In conclusion, the nonlinear profile order scheme was demonstrated to be insensitive to various motion patterns and more useful for retrospective reconstruction.展开更多
Background: Recently faster cardiac magnetic resonance (CMR) cine sequences basing on k-t compressed sensing have been developed. Purpose: To compare two compressed sensing CMR sequences-one in breath-hold technique a...Background: Recently faster cardiac magnetic resonance (CMR) cine sequences basing on k-t compressed sensing have been developed. Purpose: To compare two compressed sensing CMR sequences-one in breath-hold technique and one during free breathing—with the standard SSFP sequence with respect to regional left ventricular function assessment. Material and Methods: Left ventricular short-axis stacks of two compressed sensing sequences in breath-hold technique (sparse_HB) and during free breathing (sparse_FB;both spatial resolution, 1.8 × 1.8 × 8 mm3) and a standard SSFP cine sequence (spatial resolution, 1.9 × 1.9 × 8 mm3) were acquired in 50 patients on a 1.5 T MR system. Regional wall motion abnormalities (RWMA) were rated qualitatively (normal/hypo-/a-/dyskinesia) by two experienced readers in consensus for all cardiac segments (American Heart Association’s segment model) and sequences. RWMA detection rates were compared between sequences by kappa statistic. Results: In 13 patients, RWMA were detected in at least one cardiac segment. The RWMA detection rates were similar between CMR sequences (hypokinesia, 7.2% to 7.9%;akinesia, 0.8% to 1.3%;dyskinesia 0.3% to 0.4%) and kappa statistics revealed an almost perfect agreement in RWMA detection between both sparse and the standard SSFP sequence (standard versus sparse_HB: kappa, 0.918, p value, p value, Conclusion: Compressed sensing cine CMR acquired during breath-hold or free-breathing allows reliable RWMA detection, thus, might alternatively be used in cine CMR for regional left ventricular function assessment.展开更多
基金Supported by a grant of the National Natural Science Foundation of China(No.81371524)
文摘Objective The aim of the study was to use dynamic magnetic resonance imaging （MRI） to compare quantitative parameters of small bowel motility between healthy volunteers and patients with small bowel diseases in order to investigate the characteristics of normal and impaired bowel peristalsis. Methods A total of 44 healthy volunteers （20 men, 24 women; mean age： 36 years; range： 20-61 years） and 42 patients （28 men, 14 women; mean age： 44 years; range： 15-72 years） with organic small bowel disease were recruited in our hospital （Tongji Hospital, Tongji Medical College, Huazhong University of Sci- ence and Technology, Wuhan, China） in this prospective study approved by the hospital institutional review board. Imaging was performed using a 3.0-T scanner 45 minutes after standardized oral administration of 1500 mL non-absorbable fluid （2.5% mannitol）. A serial coronal scan was performed at selected planes for two minutes without breath-hold. Time-caliber curves were plotted at two well-distended small bowel loops in both healthy and patient groups regardless of location. Luminal diameter （LD）, contraction period （CP）, frequency of contraction （FC）, and amplitude-diameter ratio （ADR） were measured based on the graph. Results The characteristics of abnormal peristaltic parameters were assessed in different patients and compared to normal curves from healthy volunteers. A total of 37 segments with abnormal motility were confirmed by two readers in consensus, based on curve patterns and the presence of a stationary phase. Compared to normal peristalsis in healthy volunteers, five different patterns of impaired peristalsis were identified： Ⅰ, consecutive; Ⅱ, slow; Ⅲ, giant type; Ⅳ, uncoordinated; and V, akinetic. Dilated LDs were de- tected in all instances of abnormal peristalsis （P 〈 0.05）. Increased frequency was found in type Ⅰ [（8.73 ± 1.15）/min], while decreased frequency was detected in type Ⅲ peristalsis [（0.67 ± 0.29）/min]. There were no significant differences in frequency between type Ⅱ [（3.19 ±0.43）/min] and normal peristalsis [（3.45± 0.57）/min]. Apart from typeⅠ [（8.70± 0.75）/min], increased FCs were found in all other abnormal patterns. In type Ⅱ peristalsis, the average ADR value was 0.82 ± 0.08, comparable to the ADR value in the healthy group （0.83 ± 0.13）. Conclusion MR cine is an effective method for differentiating normal and abnormal small bowel peristal- sis. Plotting time-caliber curves and measuring quantitative MR cine parameters such as LD, CP, FC, and ADR offers more precise information about small bowel motility.
文摘Thunderstorms of pre-monsoon season (April – May) over Kolkata (22° 32’N, 88° 20’E), India are invariably accompanied with lightning flashes, high wind gusts, torrential rainfall, occasional hail and tornadoes which significantly affect the life and property on the ground and aviation aloft. The societal and economic impact due to such storms made accurate prediction of the weather phenomenon a serious concern for the meteorologists of India. The initiation of such storms requires sufficient moisture in lower troposphere, high surface temperature, conditional instability and a source of lift to initiate the convection. Convective available potential energy (CAPE) is a measure of the energy realized when conditional instability is released. It plays an important role in meso-scale convective systems. Convective inhibition energy (CINE) on the other hand acts as a possible barrier to the release of convection even in the presence of high value of CAPE. The main idea of the present study is to see whether a consistent quantitative range of CAPE and CINE can be identified for the prevalence of such thunderstorms that may aid in operational forecast. A statistical – fuzzy coupled method is implemented for the purpose. The result reveals that a definite range of CINE within 0 – 150 Jkg-1 is reasonably pertinent whereas no such range of CAPE depicts any consistency for the occurrence of severe thunderstorms over Kolkata. The measure of CINE mainly depends upon the altitude of the level of free convection (LFC), surface temperature (T) and surface mixing ratio (q). The box-and-whisker plot of LFC, T and q are drawn to select the most dependable parameter for the consistency of CINE in the prevalence of such thunderstorms. The skills of the parameters are evaluated through skill score analyses. The percentage error during validation with the observation of 2010 is estimated to be 0% for the range of CINE and 3.9% for CAPE.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.81501463,61471349,81671853,81571669,and 61671026)the National High Technology Research and Development Program of China(Grant No.2015AA043203)+5 种基金the Natural Science Foundation of Beijing,China(Grant No.7162112)Guangdong Innovative Research Team Program of China(Grant No.2011S013)the Natural Science Foundation of Guangdong Province,China(Grant Nos.2014A030310360 and 2014A0202015028)the Beijing Center for Mathematics and Information Interdisciplinary Sciences,Shenzhen Fundamental Research Program,China(Grant Nos.JCYJ201500731154850923 and JCYJ20140417113430665)Shenzhen High-level Oversea Talent Program,China(Grant No.KQJSCX20160301144248)the Nanshan Technology Research Fund,China(Grant No.KC2014JSQN0001A)
文摘Conventional multiple breath-hold two-dimensional （2D） balanced steady-state free precession （SSFP） presents many difficulties in cardiac cine magnetic resonance imaging （MRI）. Recently, a self-gated free-breathing three-dimensional （3D） SSFP technique has been proposed as an alternative in many studies. However, the accuracy and effectiveness of selfgating signals have been barely studied before. Since self-gating signals are crucially important in image reconstruction, a systematic study of self-gating signals and comparison with external monitored signals are needed. Previously developed self-gated free-breathing 3D SSFP techniques are used on twenty-eight healthy volunteers. Both electrocardiographic （ECG） and respiratory bellow signals are also acquired during the scan as external signals. Self-gating signal and external signal are compared by trigger and gating window. Gating window is proposed to evaluate the accuracy and effectiveness of respiratory self-gating signal. Relative deviation of the trigger and root-mean-square-deviation of the cycle duration are calculated. A two-tailed paired t-test is used to identify the difference between self-gating and external signals. A Wilcoxon signed rank test is used to identify the difference between peak and valley self-gating triggers. The results demonstrate an excellent correlation （P = 0, R 〉 0.99） between self-gating and external triggers. Wilcoxon signed rank test shows that there is no significant difference between peak and valley self-gating triggers for both cardiac （H = 0, P 〉 0.10） and respiratory （H = 0, P 〉 0.44） motions. The difference between self-gating and externally monitored signals is not significant （two-tailed paired-sample t-test： H = 0, P 〉 0.90）. The self-gating signals could demonstrate cardiac and respiratory motion accurately and effectively as ECG and respiratory bellow. The difference between the two methods is not significant and can be explained. Furthermore, few ECG trigger errors appear in some subjects while these errors are not found in self-gating signals.
文摘9月22日,索尼中国专业系统集团在北京AIT索尼影像技术学院隆重举行Cine Alta V电影摄影机发布会,作为索尼Cine Alta摄影机系统的新一代产品,同时也是影视行业的第一款采用全画幅CMOS（36.2×24.1mm）的摄影机,Cine Alta V面世的消息自9月发布以来便引发了影视行业用户持续的关注和讨论。发布会上,索尼专家和产品经理详解其性能优势、研发背景和多项突破性的＂业界第一＂,并与媒体、业界用户以现场问答、网络直播的方式进行互动,力求全面、精确、
基金supported by the National Natural Science Foundation of China(Grant Nos.81501463,61671026,81571669,and 81671853)the Natural Science Foundation of Guangdong Province,China(Grant No.2014A030310360)+3 种基金Guangdong Innovative Research Team Program of China(Grant No.2011S013)the Basic Research Project of Shenzhen City,China(Grant Nos.JCYJ20140417113430639 and JCYJ20160429172357751)the High-level Oversea Talent Program of Shenzhen City,China(Grant No.KQJSCX20160301144248)Beijing Center for Mathematics and Information Interdisciplinary Sciences of China
文摘This paper presents a nonlinear profile order scheme for three-dimensional（3D） hybrid radial acquisition applied to self-gated, free-breathing cardiac cine magnetic resonance imaging（MRI）. In self-gated, free-breathing cardiac cine MRI,respiratory and cardiac motions are unpredictable during acquisition, especially for retrospective reconstruction. Therefore,the non-uniformity of the k-space distribution is an issue of great concern during retrospective self-gated reconstruction. A nonlinear profile order with varying azimuthal increments was provided and compared with the existing golden ratio-based profile order. Optimal parameter values for the nonlinear formula were chosen based on simulations. The two profile orders were compared in terms of the k-space distribution and phantom and human image results. An approximately uniform distribution was obtained based on the nonlinear profile order for persons with various heart rates and breathing patterns.The nonlinear profile order provides more stable profile distributions and fewer streaking artifacts in phantom images. In a comparison of human cardiac cine images, the nonlinear profile order provided results comparable to those provided by the golden ratio-based profile order, and the images were suitable for diagnosis. In conclusion, the nonlinear profile order scheme was demonstrated to be insensitive to various motion patterns and more useful for retrospective reconstruction.
文摘Background: Recently faster cardiac magnetic resonance (CMR) cine sequences basing on k-t compressed sensing have been developed. Purpose: To compare two compressed sensing CMR sequences-one in breath-hold technique and one during free breathing—with the standard SSFP sequence with respect to regional left ventricular function assessment. Material and Methods: Left ventricular short-axis stacks of two compressed sensing sequences in breath-hold technique (sparse_HB) and during free breathing (sparse_FB;both spatial resolution, 1.8 × 1.8 × 8 mm3) and a standard SSFP cine sequence (spatial resolution, 1.9 × 1.9 × 8 mm3) were acquired in 50 patients on a 1.5 T MR system. Regional wall motion abnormalities (RWMA) were rated qualitatively (normal/hypo-/a-/dyskinesia) by two experienced readers in consensus for all cardiac segments (American Heart Association’s segment model) and sequences. RWMA detection rates were compared between sequences by kappa statistic. Results: In 13 patients, RWMA were detected in at least one cardiac segment. The RWMA detection rates were similar between CMR sequences (hypokinesia, 7.2% to 7.9%;akinesia, 0.8% to 1.3%;dyskinesia 0.3% to 0.4%) and kappa statistics revealed an almost perfect agreement in RWMA detection between both sparse and the standard SSFP sequence (standard versus sparse_HB: kappa, 0.918, p value, p value, Conclusion: Compressed sensing cine CMR acquired during breath-hold or free-breathing allows reliable RWMA detection, thus, might alternatively be used in cine CMR for regional left ventricular function assessment.
