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
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
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
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
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.
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。
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.
