Retrospective Electrocardiography-Gated Real-Time Cardiac Cine MRI at 3T: Comparison with Conventional Segmented Cine MRI

OBJECTIVE: Segmented cardiac cine magnetic resonance imaging (MRI) is the gold standard for cardiac ventricular volumetric assessment. In patients with difficulty in breath-holding or arrhythmia, this technique may generate images with inadequate quality for diagnosis. Real-time cardiac cine MRI has been developed to address this limitation. We aimed to assess the performance of retrospective electrocardiography-gated real-time cine MRI at 3T for left ventricular (LV) volume and mass measurement. MATERIALS AND METHODS: Fifty-one patients were consecutively enrolled. A series of short-axis cine images covering the entire left ventricle using both segmented and real-time balanced steady-state free precession cardiac cine MRI were obtained. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), and LV mass were measured. The agreement and correlation of the parameters were assessed. Additionally, image quality was evaluated using European CMR Registry (Euro-CMR) score and structure visibility rating. RESULTS: In patients without difficulty in breath-holding or arrhythmia, no significant difference was found in Euro-CMR score between the two techniques (0.3 ± 0.7 vs. 0.3 ± 0.5, p > 0.05). Good agreements and correlations were found between the techniques for measuring EDV, ESV, EF, SV, and LV mass. In patients with difficulty in breath-holding or arrhythmia, segmented cine MRI had a significant higher Euro-CMR score (2.3 ± 1.2 vs. 0.4 ± 0.5, p < 0.001). CONCLUSION: Real-time cine MRI at 3T allowed the assessment of LV volume with high accuracy and showed a significantly better image quality compared to that of segmented cine MRI in patients with difficulty in breath-holding and arrhythmia.

MRI characteristics and clinical value of hypertrophic cardiomyopathy with scar-like late enhancement / 中华放射学杂志

Objective To explore the prevalence,MRI characteristics and clinical evaluation of hypertrophic cardiomyopathy(HCM) patients with infarct-like late enhancement(LGE).Methods HCM patients were diagnosed via cardiac magnetic resonance(CMR) from October,2009 to December,2013.1 411 HCM patients were diagnosed via CMR,465 patients with LGE,of which 24 patients with infarct-like LGE (primarily in the subendocardium).Clinical and MRI data of patients demonstrating infarct-like LGE were retrospectively analyzed.All the HCM patients with LGE were followed up in the clinic or by telephone interview.Major adverse cardiovascular events(MACE) were defined as malignant ventricular arrhythmia events,including sudden cardiac death,ventricular tachycardia/fibrillation,implantable cardioverter defibrillator(ICD) discharge and heart failure events,including death from heart failure,heart transplantation.The correlation between left ventricle ejection fraction and subendocardial LGE volume fraction was evaluated by Pearson correlation analysis.Comparison of subendocardial LGE volume fraction between obstructed and non-obstructed left ventricular outflow tract (LVOT) group was performed using independent sample t test.Prognosis of patients with infarct-like LGE and other LGE patterns was compared using Kaplan-Meier curves.Results The prevalence of infarct-like LGE were 0.05％(24/465) among patients with LGE.Mean left venricle ejection fraction(LVEF) was (56.20±3.60)％ and mean LGE volume fraction was (14.52 ± 12.73)％.According to the American Heart Association (AHA) 17-segment model,infarct-like LGE was most frequent in 14 segment(10 patients),followed by 9,15 (8 patients,respectively) and 3,8,16 (7 patients,respectively) segments,mainly distributed in left ventricular septum and apical portion.EF value was inversely correlated with mean LGE volume fraction(r=-0.85,P＜0.05).Mean follow up time was (4.25t± 1.35) years for all the HCM patients with LGE,and event-free survival rate was lower in HCM patients with infarct-like LGE than patients with other LGE patterns(P＜0.001).Conclusions Infarct-like LGE is a special manifestation in HCM patients,which shows worse prognosis than other LGE patterns.Infarct-like LGE volume fraction is associated with LVEF and LVOT.

MRI characteristics and outcomes of end-stage hypertrophic cardiomyopathy / 中国医学影像技术

Objective To clarify the MRI characteristics and outcomes of patients with end stage hypertrophic cardiomyopathy (ES-HCM).Methods Clinical and MRI data of 57 ES-HCM patients were retrospectively analyzed.ES-HCM pa tients were divided into dilated phenotype group (D-ES group,n=39) and restrictive phenotype group (R-ES group,n=18).MRI characteristics and outcomes of patients were compared between both groups.Results The incidence of atrial fi brillation and edema of lower extremity was significantly higher in R-ES than those in D-ES (72.22％ [13/18] vs 30.77％ [12/39];50.00％ [9/18] vs 23.08％ [9/39];both P＜0.05).The left ventricular ejection function,left and right atrial anteroposte rior diameter of D-ES group were significant smaller than those of RRES group (all P＜0.05),while the left ventricular (LV) short axis diameter,LV end diastolic/systolic volume and LV end diastolic/systolic volume index of D-ES were significantly greater than those of R-ES group (all P＜0.05).Log-rank test found no significant difference between both groups in cardiovascular death/ heart transplant events (x2 =1.135,P=0.287).Late gadolinium enhancement (LGE) volume fraction was significantly larger in D-ES ([36.1±14.8]％) than in R-ES ([21.0±9.0]％;P＜0.05).There was a significant correlation between LGE volume fraction and cardiovascular death/heart transplant events (HR:1.054,P＜0.05).Conclusion ES-HCM patients have expanded clinical expression and MRI characteristics,including dilated phenotype and restrictive phenotype.MRI has an important application value in the diagnosis and prognosis evaluation of ES-HCM.

MRI late gadolinium enhancement of left ventricular apical aneurysms in hypertrophic cardiomyopathy / 中华放射学杂志

Objectives To discuss the characteristics of late gadolinium enhancement (LGE) magnetic resonance (MR) imaging in patients with hypertrophic cardiomyopathy (HCM) and left ventricular apical aneurysm (LVAA) and its related prognostic value. Methods Thirty HCM patients with LVAA were collected from August 2004 to August 2013. All cases with coronary artery diseases were ruled out, and all patients underwent LGE derived by cardiac MR (CMR). Five cases of LVAA were pathological confirmed. Atrial and ventricular diameters, apical aneurysm diameters and left ventricular ejection fraction were measured, and apical aneurysm LGE was evaluated. All patients were then followed up. Comparisons in continuous parameters between patients with or without LGE were performed by independent t test. A Cox proportional hazard model was used to estimate the hazard rate for adverse cardiovascular events. Results LGE was identified in 21 LVAAs and non-LGE in 9 LVAAs. Between two groups, there was no significant difference in the size of LVAA [(16.4 ± 11.5) mm vs. (20.3 ± 9.8) mm, P=0.63]. In particular, the complete transition from non-LGE to LGE LVAA was recorded during follow-up in one patient. Pathological findings confirmed that LGE indicated fibrous tissue in LVAA, and LVAA without LGE indicated viable myocardium. The follow-up suggested that the patterns and the size of LVAA were associated with the adverse events in these patients (LGE of LVAA, HR=7.94, P=0.064; the size of LVAA, HR=1.08, P=0.009). Conclusions LGE-MR had important clinical significance in HCM patients with LVAA. LGE in LVAA corresponded with the fibrous tissue and was associated with the prognosis.

Comparison of cerebral white matter fractional anisotropy and metabolite concentrations measured by 1 H-MRS in healthy adults / 实用放射学杂志

Objective To investigate the relationship between cerebral white matter fractional anisotropy(FA)and metabolite con-centrations measured by 1 H magnetic resonance spectroscopy(1 H-MRS)in healthy adults.Methods Diffusion tensor imaging(DTI) and 1 H-MRS were acquired from thirty-one healthy adults at 3.0 T MR system.The concentrations of N-acetylaspartate(NAA), choline(Cho),creatine(Cr),the ratios of NAA/Cr and FA values of DTI were measured in 353 voxels,covering the bilateral medium corona radiata.According to the age,all voxels were divided into two groups:the senior group (mean age=29 years),and the senior group(mean age=5 6 years).The correlations between FA values and age were analyzed using Pearson’s correlation coefficients.The correlations between FA values and metabolite concentrations were estimated using partial correlations test controlling for the age re-lated bias.Results Pearson’s correlation analysis revealed a negative correlation between FA values and age in 353 voxels(r=-0.146,P<0.05),senior group(r=-0.204,P<0.05)and senior group(r=-0.162,P<0.05).Only the correlation between NAA and FA values were significant(r=0.339,P<0.05;r=0.213,P<0.05;r=0.430,P<0.05).There were positive relation-ships between FA values and NAA/Cr among 353 voxels (r=0.166,P<0.05)and senior group(r=0.305,P<0.05).Conclusion There are correlations between cerebral white matter FA values and metabolite concentrations measured by 1 H-MRS .Combining 1 H-MRS with DTI can reveal the relationship between microscopic white matter integrity and metabolic characteristics of the white matter.