BACKGROUND 7T cardiac magnetic resonance imaging(MRI)introduces several advantages,as well as some limitations,compared to lower-field imaging.The capabilities of ultra-high field(UHF)MRI have not been fully exploited...BACKGROUND 7T cardiac magnetic resonance imaging(MRI)introduces several advantages,as well as some limitations,compared to lower-field imaging.The capabilities of ultra-high field(UHF)MRI have not been fully exploited in cardiac functional imaging.AIM To optimize 7T cardiac MRI functional imaging without the need for conducting B1 shimming or subject-specific tuning,which improves scan efficiency.In this study,we provide results from phantom and in vivo scans using a multi-channel transceiver modular coil.METHODS We investigated the effects of adding a dielectric pad at different locations next to the imaged region of interest on improving image quality in subjects with different body habitus.We also investigated the effects of adjusting the imaging flip angle in cine and tagging sequences on improving image quality,B1 field homogeneity,signal-to-noise ratio(SNR),blood-myocardium contrast-to-noise ratio(CNR),and tagging persistence throughout the cardiac cycle.RESULTS The results showed the capability of achieving improved image quality with high spatial resolution(0.75 mm×0.75 mm×2 mm),high temporal resolution(20 ms),and increased tagging persistence(for up to 1200 ms cardiac cycle duration)at 7T cardiac MRI after adjusting scan set-up and imaging parameters.Adjusting the imaging flip angle was essential for achieving optimal SNR and myocardium-toblood CNR.Placing a dielectric pad at the anterior left position of the chest resulted in improved B1 homogeneity compared to other positions,especially in subjects with small chest size.CONCLUSION Improved regional and global cardiac functional imaging can be achieved at 7T MRI through simple scan set-up adjustment and imaging parameter optimization,which would allow for more streamlined and efficient UHF cardiac MRI.展开更多
Objective To evaluate the application of phasecontrast cine magnetic resonance imaging (MRI) in endoscopic aqueductoplasty for patients with obstructive hydrocephalus. Methods The clinical diagnosis of hydrocephalus d...Objective To evaluate the application of phasecontrast cine magnetic resonance imaging (MRI) in endoscopic aqueductoplasty for patients with obstructive hydrocephalus. Methods The clinical diagnosis of hydrocephalus due to aqueduct obstruction in 23 patients was confirmed by phase contrast cine MRI examination.展开更多
This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-con...This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-contrast magnetic resonance angiography slice was applied perpendicular to the internal carotid artery and the vertebral artery at C2 level. For each subject, the velocity encoding was set from 30 to 90 cm/s with an interval of 10 cm/s for a total of seven settings. Various velocity encodings greatly affected blood flow volume, maximal blood flow velocity and mean blood flow velocity in the internal carotid artery, but did not significantly affect vertebral arteries and jugular veins. When velocity encoding was 60-80 cm/s, the inflow blood volume was 655 _＋ 118 mL/min, and the outflow volume was 506 _＋ 186 mL/min. The ratio of outflow/inflow was steady at 0.78-0.83, and there was no aliasing in any of the images. These findings suggest that velocity encodings of 60 80 cm/s should be selected during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography.展开更多
Cardiac masses diagnosis and treatment are a true challenge,although they are infrequently encountered in clinical practice.They encompass a broad set of lesions that include neoplastic(primary and secondary),non-neop...Cardiac masses diagnosis and treatment are a true challenge,although they are infrequently encountered in clinical practice.They encompass a broad set of lesions that include neoplastic(primary and secondary),non-neoplastic masses and pseudomasses.The clinical presentation of cardiac tumors is highly variable and depends on several factors such as size,location,relation with other structures and mobility.The presumptive diagnosis is made based on a preliminary non-invasive diagnostic work-up due to technical difficulties and risks associated with biopsy,which is still the diagnostic gold standard.The findings should always be interpreted in the clinical context to avoid misdiagnosis,particularly in specific conditions(e.g.,infective endocarditis or thrombi).The modern multi-modality imaging techniques has a key role not only for the initial assessment and differential diagnosis but also for management and surveillance of the cardiac masses.Cardiovascular magnetic resonance(CMR)allows an optimal non-invasive localization of the lesion,providing multiplanar information on its relation to surrounding structures.Moreover,with the additional feature of tissue characterization,CMR can be highly effective to distinguish pseudomasses from masses,as well as benign from malignant lesions,with further differential diagnosis of the latter.Although histopathological assessment is important to make a definitive diagnosis,CMR plays a key role in the diagnosis of suspected cardiac masses with a great impact on patient management.This literature review aims to provide a comprehensive overview of cardiac masses,from clinical and imaging protocol to pathological findings.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
A total of 50 healthy volunteers aged between 18 and 54 years underwent phase-contrast cine MR to assess cerebrospinal fluid flow characteristics in different regions of the vertebral canal. The results revealed that ...A total of 50 healthy volunteers aged between 18 and 54 years underwent phase-contrast cine MR to assess cerebrospinal fluid flow characteristics in different regions of the vertebral canal. The results revealed that the cerebrospinal fluid peak flow velocity and peak flow rate in the systolic phase were significantly greater than those in the diastolic phase at the same level in the subarachnoid space of the cervical spinal canal. The ventral peak flow velocity and peak flow rate were significantly greater than the post-lateral peak flow velocity and flow rate, while there were no differences between left and right post-lateral subarachnoid peak velocity and flow rate. Moreover, there were no significant differences in peak flow velocity and peak flow rate between the systolic and diastolic phases, ventral, right post-lateral or left post-lateral peak flow velocity and peak flow rate at the same level in the subarachnoid space of the cervical spinal canal among different age groups （18 24, 25 34, 35-44, ≥45 years）.展开更多
目的探讨磁共振相位电影对比成像法(PC cine MRI)在脑积水诊断、治疗中的应用价值。方法对10例健康志愿者及6例脑积水患者采用PC cine MRI对中脑导水管脑脊液动力学测量,并测量术后脑脊液变化,比较治疗前后的差异。结果正常志愿者PC cin...目的探讨磁共振相位电影对比成像法(PC cine MRI)在脑积水诊断、治疗中的应用价值。方法对10例健康志愿者及6例脑积水患者采用PC cine MRI对中脑导水管脑脊液动力学测量,并测量术后脑脊液变化,比较治疗前后的差异。结果正常志愿者PC cine MRI结果显示中脑导水管的脑脊液流动呈正弦曲线;梗阻性脑积水PC cine MRI显示脑脊液流动双向流动减弱,术后呈正弦曲线;交通性脑积水脑脊液双向流动加快,V-P分流术后流动曲线呈不规则,但双向流动减慢;V-P分流术失败显示分流管-脑室端无脑脊液信号,再次手术后出现强弱不等的信号。结论 PC cine MRI在脑积水的诊断及手术选择中有指导意义,并且可以评估术后疗效。展开更多
文摘BACKGROUND 7T cardiac magnetic resonance imaging(MRI)introduces several advantages,as well as some limitations,compared to lower-field imaging.The capabilities of ultra-high field(UHF)MRI have not been fully exploited in cardiac functional imaging.AIM To optimize 7T cardiac MRI functional imaging without the need for conducting B1 shimming or subject-specific tuning,which improves scan efficiency.In this study,we provide results from phantom and in vivo scans using a multi-channel transceiver modular coil.METHODS We investigated the effects of adding a dielectric pad at different locations next to the imaged region of interest on improving image quality in subjects with different body habitus.We also investigated the effects of adjusting the imaging flip angle in cine and tagging sequences on improving image quality,B1 field homogeneity,signal-to-noise ratio(SNR),blood-myocardium contrast-to-noise ratio(CNR),and tagging persistence throughout the cardiac cycle.RESULTS The results showed the capability of achieving improved image quality with high spatial resolution(0.75 mm×0.75 mm×2 mm),high temporal resolution(20 ms),and increased tagging persistence(for up to 1200 ms cardiac cycle duration)at 7T cardiac MRI after adjusting scan set-up and imaging parameters.Adjusting the imaging flip angle was essential for achieving optimal SNR and myocardium-toblood CNR.Placing a dielectric pad at the anterior left position of the chest resulted in improved B1 homogeneity compared to other positions,especially in subjects with small chest size.CONCLUSION Improved regional and global cardiac functional imaging can be achieved at 7T MRI through simple scan set-up adjustment and imaging parameter optimization,which would allow for more streamlined and efficient UHF cardiac MRI.
文摘Objective To evaluate the application of phasecontrast cine magnetic resonance imaging (MRI) in endoscopic aqueductoplasty for patients with obstructive hydrocephalus. Methods The clinical diagnosis of hydrocephalus due to aqueduct obstruction in 23 patients was confirmed by phase contrast cine MRI examination.
基金the Medical Program of the Scientific & Technical Foundation in Xiamen(MRI study of chronic cerebrovascular insufficiency) in 2008,No.3502Z20084028
文摘This study investigated the effect of velocity encoding on measurement of brain blood flow and blood volume of inflow and outflow using phase-contrast magnetic resonance angiography. A single two-dimensional phase-contrast magnetic resonance angiography slice was applied perpendicular to the internal carotid artery and the vertebral artery at C2 level. For each subject, the velocity encoding was set from 30 to 90 cm/s with an interval of 10 cm/s for a total of seven settings. Various velocity encodings greatly affected blood flow volume, maximal blood flow velocity and mean blood flow velocity in the internal carotid artery, but did not significantly affect vertebral arteries and jugular veins. When velocity encoding was 60-80 cm/s, the inflow blood volume was 655 _＋ 118 mL/min, and the outflow volume was 506 _＋ 186 mL/min. The ratio of outflow/inflow was steady at 0.78-0.83, and there was no aliasing in any of the images. These findings suggest that velocity encodings of 60 80 cm/s should be selected during measurement of cerebral blood flow volume using phase-contrast magnetic resonance angiography.
文摘Cardiac masses diagnosis and treatment are a true challenge,although they are infrequently encountered in clinical practice.They encompass a broad set of lesions that include neoplastic(primary and secondary),non-neoplastic masses and pseudomasses.The clinical presentation of cardiac tumors is highly variable and depends on several factors such as size,location,relation with other structures and mobility.The presumptive diagnosis is made based on a preliminary non-invasive diagnostic work-up due to technical difficulties and risks associated with biopsy,which is still the diagnostic gold standard.The findings should always be interpreted in the clinical context to avoid misdiagnosis,particularly in specific conditions(e.g.,infective endocarditis or thrombi).The modern multi-modality imaging techniques has a key role not only for the initial assessment and differential diagnosis but also for management and surveillance of the cardiac masses.Cardiovascular magnetic resonance(CMR)allows an optimal non-invasive localization of the lesion,providing multiplanar information on its relation to surrounding structures.Moreover,with the additional feature of tissue characterization,CMR can be highly effective to distinguish pseudomasses from masses,as well as benign from malignant lesions,with further differential diagnosis of the latter.Although histopathological assessment is important to make a definitive diagnosis,CMR plays a key role in the diagnosis of suspected cardiac masses with a great impact on patient management.This literature review aims to provide a comprehensive overview of cardiac masses,from clinical and imaging protocol to pathological findings.
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.
基金supported by the Science and Technology Support Program of Hebei Province(Cervical spinal canal cerebrospinal fluid movement using 3.0TMR fast phase-contrast cine imaging),No.112061179D
文摘A total of 50 healthy volunteers aged between 18 and 54 years underwent phase-contrast cine MR to assess cerebrospinal fluid flow characteristics in different regions of the vertebral canal. The results revealed that the cerebrospinal fluid peak flow velocity and peak flow rate in the systolic phase were significantly greater than those in the diastolic phase at the same level in the subarachnoid space of the cervical spinal canal. The ventral peak flow velocity and peak flow rate were significantly greater than the post-lateral peak flow velocity and flow rate, while there were no differences between left and right post-lateral subarachnoid peak velocity and flow rate. Moreover, there were no significant differences in peak flow velocity and peak flow rate between the systolic and diastolic phases, ventral, right post-lateral or left post-lateral peak flow velocity and peak flow rate at the same level in the subarachnoid space of the cervical spinal canal among different age groups （18 24, 25 34, 35-44, ≥45 years）.
文摘目的探讨磁共振相位电影对比成像法(PC cine MRI)在脑积水诊断、治疗中的应用价值。方法对10例健康志愿者及6例脑积水患者采用PC cine MRI对中脑导水管脑脊液动力学测量,并测量术后脑脊液变化,比较治疗前后的差异。结果正常志愿者PC cine MRI结果显示中脑导水管的脑脊液流动呈正弦曲线;梗阻性脑积水PC cine MRI显示脑脊液流动双向流动减弱,术后呈正弦曲线;交通性脑积水脑脊液双向流动加快,V-P分流术后流动曲线呈不规则,但双向流动减慢;V-P分流术失败显示分流管-脑室端无脑脊液信号,再次手术后出现强弱不等的信号。结论 PC cine MRI在脑积水的诊断及手术选择中有指导意义,并且可以评估术后疗效。
