Myocardial septic seeding secondary to infective endocarditis: diagnosis by cardiac magnetic resonance imaging

The International Journal of Cardiovascular Imaging -     

MRI电影对月经过多子宫肌瘤患者子宫蠕动的研究

目的应用MR电影成像技术(cine MRI)探讨月经过多子宫肌瘤患者排卵期子宫蠕动情况及肌瘤位置对子宫蠕动的影响。材料与方法采用1.5 T MRI仪对30名健康志愿者及30例月经过多子宫肌瘤患者于排卵期行盆腔T1轴面、T2-抑脂轴面、T2矢状面及子宫cine MR扫描。比较健康志愿者与月经过多肌瘤患者子宫正常蠕动存在率及蠕动频率,分析肌瘤位置与蠕动形式的关系。结果月经过多子宫肌瘤患者排卵期子宫正常蠕动存在率及蠕动频率较健康志愿者显著降低,两者均有统计学意义(P值均0.01),黏膜下肌瘤患者主要表现为无蠕动,肌壁间肌瘤患者蠕动形式多样。结论月经过多子宫肌瘤患者排卵期子宫正常蠕动显著减少,不利于排卵期精子快速进入输卵管;Cine MRI有助于月经过多子宫肌瘤患者子宫蠕动的评价,为临床提供子宫蠕动的功能信息。     

Left ventricular geometric remodeling in relation to non-ischemic scar pattern on cardiac magnetic resonance imaging

Left ventricular (LV) remodeling and myocardial fibrosis have been linked to adverse heart failure outcomes. Mid wall late gadolinium enhancement (MW-LGE) on cardiac magnetic resonance (CMR) imaging is well-associated with non-ischemic cardiomyopathy (NICM), but prevalence in ischemic cardiomyopathy (ICM) and association with remodeling are unknown. The population comprised patients with systolic dysfunction [LV ejection fraction (LVEF ≤ 40 %)]. CMR was used to identify MW-LGE, conventionally defined as fibrosis of the mid-myocardial or epicardial aspect of the LV septum. 285 patients were studied. MW-LGE was present in 12 %, and was tenfold more common with NICM (32 %) versus ICM (3 %, p < 0.001). However, owing to higher prevalence of ICM, 15 % of patients with MW-LGE had ICM. LV wall stress was higher (p = 0.02) among patients with, versus those without, MW-LGE despite similar systolic blood pressure (p = 0.24). In multivariate analysis, MW-LGE was associated with CMR-quantified LV end-diastolic volume (p = 0.03) independent of LVEF and mass. Incorporation of clinical and imaging variables demonstrated MW-LGE to be associated with higher LV end-diastolic volume (OR 1.13, CI 1.004–1.27 per 10 ml/m², p = 0.04) after controlling for presence of NICM (OR 16.0, CI 5.8–44.1, p < 0.001). While more common in NICM, MW-LGE can occur in ICM and is a marker of LV chamber dilation irrespective of cardiomyopathic etiology.     

Pacing in high field cardiac magnetic resonance imaging:

Currently, cardiac MRI is contraindicated in patients with an implanted pacemaker or ICD due to safety hazards. However, MRI is promising to play a key role in cardiac diagnostics in near future. This study examined a rat with an implanted pacemaker pacing at a rate of 460/min with high field cardiac MRI. This study showed that pacing during cardiac imaging at 7 Tesla was possible. The pacemaker program was not disturbed by the high field or the strong gradients (maximum dB/dt 400 mT/s). The only noticeable effect on the MRI signal was a signal void of 2 cm around the device.     

Myocardial iron deposition in β-Thalassemia studied by magnetic resonance imaging

Myocardial iron deposition is a common finding in β-thalassemia. The iron content of the myocardium was assessed using the T2 relaxation time of the heart. The T2 relaxation time of the liver and skeletal muscle was also assessed in order to study the relation of iron deposition between heart, liver and skeletal muscle. ECG gated spin echo images were obtained from thirty-eight consecutive adult thalassemic patients examined in an outpatient clinic, aged (x±SD) 25±6 years, using a 0.5 T system. Patients were divided into groups A and B, according to their average serum ferritin levels of the preceding five years (> or < 2000 ng/ml). Results were compared with nine controls, aged 24±7 years. Heart T2 relaxation time in the control group (x±SD)(48.3±5.5 msec) was higher compared to group A (28.4±6.7 msec, p<0.001) but not to group B (43.4±7.4 msec). The T2 relaxation time of the heart correlated positively with the T2 relaxation time of the liver (r=0.68, p<0.001) and negatively with ferritin levels (r=-0.67, p<0.001). There was no correlation with the T2 relaxation time of skeletal muscle. This study indicates that regularly transfused β-thalassemia patients may present with a broad variation of heart iron deposition which, however, is related to serum ferritin levels.     

Metastatic cardiac liposarcoma: diagnosis by transesophageal echocardiography and magnetic resonance imaging

The most superior portion of the right atrium is not well visualized by transthoracic echocardiography. This limits the ability of the technique to detect intracardiac disease in this area. We describe a 41-year-old man with a history of liposarcoma in whom transthoracic echocardiography was unable to elucidate a right atrial metastasis. Transesophageal echocardiography demonstrated the morphology and extent of the large right atrial mass. These findings were well correlated with both magnetic resonance imaging and surgery.     

Primer on cardiac magnetic resonance imaging: how to perform the examination

Cardiac magnetic resonance imaging is made possible by utilizing an external signal, the patient's own electrocardiogram, to time image acquisition. ECG gated cardiac magnetic resonance examination may be performed using spin-echo or gradient reversal techniques or their newer k-space segmented variants. Spin-echo techniques provide the highest contrast between rapidly moving blood and the cardiac chambers and arteries and veins containing the blood, but are of relatively low temporal resolution. Gradient reversal acquisition, however, provides higher temporal resolution ideal for evaluating changes in myocardial thickening, ventricular wall motion abnormalities, and changes in chamber volume through the cardiac cycle; gradient reversal technique has significantly lower contrast resolution. Careful attention to the details of image acquisition will provide high-quality images of the heart and great arteries from which important morphologic and physiological information may be obtained, aiding in the diagnosis and management of patients with cardiovascular disease.     

Myocardial area at risk after ST-elevation myocardial infarction measured with the late gadolinium enhancement after scar remodeling and T2-weighted cardiac magnetic resonance imaging

To evaluate the myocardial area at risk (AAR) measured by the endocardial surface area (ESA) method on late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) when applied after scar remodeling (3 months after index infarction) compared to T2-weighted CMR imaging. One hundred and sixty nine patients with ST-elevation myocardial infarction, treated with primary percutaneous coronary intervention, underwent one CMR within 1 week after index treatment to determine the AAR with T2-weighted imaging and a second scan 3 months after to measure AAR with the ESA method. There was a moderate correlation between the two methods (r = 0.86; P < 0.001). The AAR was significantly higher measured with T2-weighted imaging than with the ESA methods (32 ± 11% of left ventricle (LV) vs. 26 ± 10%LV; P < 0.001). The mean difference was 6 ± 6%LV. Furthermore, the mean difference between the two methods was statistical higher in the patients with myocardial salvage index ≥0.90 than in the remaining patients (9 ± 8%LV vs. 6 ± 5%LV; P = 0.02). The ESA method performed after scar remodeling (3 months following STEMI) yields significantly lower AAR′s and myocardial salvage indices compared to the T2-weighted method. Therefore, T2-weighted CMR plus LGE is the method of choice to assess AAR and myocardial salvage index using CMR. However, the ESA method is an easy and valid method for determining AAR, which can be used in settings where T2-weighted imaging has not been obtained in the acute phase.     

Angiographic correlations of patients with small vessel disease diagnosed by adenosine-stress cardiac magnetic resonance imaging

Cardiac magnetic resonance imaging (CMR) with adenosine-stress myocardial perfusion is gaining importance for the detection and quantification of coronary artery disease (CAD). However, there is little knowledge about patients with CMR-detected ischemia, but having no relevant stenosis as seen on coronary angiography (CA). The aims of our study were to characterize these patients by CMR and CA and evaluate correlations and potential reasons for the ischemic findings. 73 patients with an indication for CA were first scanned on a 1.5T whole-body CMR-scanner including adenosine-stress first-pass perfusion. The images were analyzed by two independent investigators for myocardial perfusion which was classified as subendocardial ischemia (n = 22), no perfusion deficit (n = 27, control 1), or more than subendocardial ischemia (n = 24, control 2). All patients underwent CA, and a highly significant correlation between the classification of CMR perfusion deficit and the degree of coronary luminal narrowing was found. For quantification of coronary blood flow, corrected Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) was evaluated for the left anterior descending (LAD), circumflex (LCX) and right coronary artery (RCA). The main result was that corrected TFC in all coronaries was significantly increased in study patients compared to both control 1 and to control 2 patients. Study patients had hypertension or diabetes more often than control 1 patients. In conclusion, patients with CMR detected subendocardial ischemia have prolonged coronary blood flow. In connection with normal resting flow values in CAD, this supports the hypothesis of underlying coronary microvascular impairment. CMR stress perfusion differentiates non-invasively between this entity and relevant CAD.     

Acupuncture effects on cardiac functions measured by cardiac magnetic resonance imaging in a feline model

The usefulness of acupuncture (AP) as a complementary and/or alternative therapy in animals is well established but more research is needed on its clinical efficacy relative to conventional therapy, and on the underlying mechanisms of the effects of AP. Cardiac magnetic resonance imaging (CMRI), an important tool in monitoring cardiovascular diseases, provides a reliable method to monitor the effects of AP on the cardiovascular system. This controlled experiment monitored the effect electro-acupuncture (EA) at bilateral acupoint Neiguan (PC6) on recovery time after ketamine/xylazine cocktail anesthesia in healthy cats. The CMRI data established the basic feline cardiac function index (CFI), including cardiac output and major vessel velocity. To evaluate the effect of EA on the functions of the autonomic nervous and cardiovascular systems, heart rate, respiration rate, electrocardiogram and pulse rate were also measured. Ketamine/xylazine cocktail anesthesia caused a transient hypertension in the cats; EA inhibited this anesthetic-induced hypertension and shortened the post-anesthesia recovery time. Our data support existing knowledge on the cardiovascular benefits of EA at PC6, and also provide strong evidence for the combination of anesthesia and EA to shorten post-anesthesia recovery time and counter the negative effects of anesthetics on cardiac physiology.     

Myocardial perfusion imaging: clinical experience and recent progress in radionuclide scintigraphy and magnetic resonance imaging

In the past 20 years, radionuclide scintigraphy has proven to be a sensitive clinical tool in the assessment of myocardial perfusion abnormalities. Magnetic resonance imaging may also be used to study myocardial perfusion, but its potential value still has to emerge in the clinical setting. This review addresses the potential and achievements of both methods in clinical cardiology.     

Prospective comparison of echocardiography versus cardiac magnetic resonance imaging in patients with Ebstein's anomaly

Ebstein's anomaly (EA) is primarily diagnosed by echocardiography. The purpose of this study was to compare echocardiography and magnetic resonance imaging (MRI) in EA. Data from cardiac MRI and echocardiography were prospectively collected from 16 patients with EA. Imaging data also were compared with intraoperative findings. Information provided by MRI and echocardiography were comparable for left ventricular size and function, tricuspid valve repairability, qualitative assessment of right-sided cavities, and visibility of septal and anterior tricuspid valve leaflets. The posterior tricuspid valve leaflet and tricuspid valve fenestrations were better visualized with MRI; associated heart defects were equally recognized, apart from small shunts that tended to be more readily diagnosed with echocardiography. Quantification of right-cavity size and right ventricular ejection fraction was possible only with cardiac MRI. The degree of tricuspid valve regurgitation was underestimated by echocardiography (2 patients) and by MRI (4 patients) when compared with intraoperative assessment. When evaluating EA, echocardiography and MRI provide complementary data. For visualization of the posterior tricuspid valve leaflet and quantitative assessment of right ventricular size and function, MRI is preferable. For appropriate risk stratification in EA, both MRI and echocardiography should be performed before cardiac surgery.     

二维超声应变评价慢性肾病心肌损害的价值

目的 探讨整体二维超声应变成像评价慢性肾病(CKD)心肌损害的价值.方法 39例CKD患者,其中20例为2～3期CKD患者(组1),19例为4～5期CKD患者(组2),设29例正常对照.使用常规超声心动图评价左室结构和功能,使用二维超声应变成像评价心肌整体纵向、周向应变与应变率.结果 CKD患者左室射血分数等收缩功能指标与对照组的差异无统计学意义,CKD组1和组2整体纵向应变、应变率均低于对照组,组2整体纵向应变与应变率低于组1(P＜0.05).CKD组1整体周向应变、应变率与对照组的差异无统计学意义,而CKD组2整体周向应变与应变率低于对照组(P＜0.05).CKD组整体纵向应变与肾小球滤过率呈正相关(r=0.376,P＜0.001),与心肌质量指数呈负相关(r=-0.473,P＜0.01).结论 整体二维应变成像对评价CKD患者亚临床心肌功能损害有重要价值.

Abstract：

Objective To evaluate whether global 2-dimensional strain imaging can offer additional benefit over conventional echocardiography to detect subclinical myocardial damage in patients with chronic kidney disease(CKD). Methods Conventional echocardiography and global 2-dimension strain imaging were performed in 39 patients with CKD [23 men and 16 women,mean age (45.6± 14.6) years] and 29 control subjects. Twenty patients had CKD stage 2 or 3(group 1 ) and nineteen patients had CKD stage 4 or 5(group 2). Left ventricular structure and function were evaluated by conventional echocardiography. Global longitudinal and circumferential strain and strain rate were analyzed. Results There were no differences in ejection fraction and fraction shortening between CKD patients and controls. Compared with controls, CKD groups had significantly decreased value of global longitudinal strain and strain rate. Global longitudinal strain decreased from - (23.8 ± 3.1 ) % in controls to - ( 18. 5 ± 2.4) % in group 1 and to - (15.2 ± 3.2) % in group 2 ( P ＜0. 001 ). Compared with controls, there was no difference in global circumferential strain and strain rate between group 1 and controls, but global circumferential strain and strain rate of group 2 was reduced [ - (17.1± 3. 0) % vs -(21.2±2.8)%, P＜0.05;-(1.0±0.2)% vs -(1.3±0.3)%, P＜0.05]. In correlation analyses, global longitudinal strain was positively related to eGFR( r =0. 376, P ＜0. 001 ) and inversely related to left ventricular mass index( r = - 0. 473, P ＜0.01). Conclusions Global 2-dimensional strain imaging may represent a useful tool for the assessment of subclinical myocardial dysfunction in patients with CKD.     

Scar extent evaluated by late gadolinium enhancement CMR: a powerful predictor of long term appropriate ICD therapy in patients with coronary artery disease

Background

Coronary artery disease (CAD) patients are at risk for life-threatening ventricular arrhythmias (VA) related to scar tissue. Late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) can accurately identify myocardial scar extent. It has been shown that scar extent, particularly scar transmurality, percent scar and scar mass, are associated with the occurrence of appropriate implantable cardioverter-defibrillator (ICD) therapy. However, quantification of transmurality extent has never been studied. The purpose of our study was to evaluate whether different methods quantifying scar transmurality, percent scar and scar mass (assessed with LGE-CMR) can predict appropriate ICD therapy in CAD patients with a long term follow-up period.

Methods and results

We enrolled retrospectively 66 patients with chronic CAD referred for primary or secondary preventive ICD implantation and LGE-CMR before ICD implantation. Using LGE-CMR, scar extent was assessed by measuring scar mass, percent scar and transmural scar extent using four different methods. The median follow-up duration was 41.5 months (interquartile range 22–52). The endpoint was the occurrence of appropriate device therapy and occurred in 14 patients. Pre-ICD revascularization and transmural scar extent were significantly associated with the study endpoint but the latter was especially highly dependent on the method used. Patients with appropriate device therapy had also larger scar mass (29.6 ± 14.5 g vs 17.1 ± 8.8 g, p = 0.004), and larger percent scar (15.1 ± 8.2% vs 9.9 ± 5.6%, p = 0.03) than patients without appropriate device therapy. In multivariate analysis, scar extent variables remained significantly associated with the study end-point.

Conclusions

In this study of CAD patients implanted for primary or secondary preventive ICD, pre-ICD revascularization and scar extent studied by LGE-CMR were significantly associated with appropriate device therapy and can identify a subgroup of CAD patients with an increased risk of life-threatening VA. Depending of the method used, transmural scar extent may vary significantly and needs further studies to obtain a validated and consensual study method.     

Myocardial fibrosis and quality of life in patients with non-ischemic cardiomyopathy: a cardiovascular magnetic resonance imaging study

Myocardial fibrosis (MF) is a common pathophysiologic endpoint in non-ischemic cardiomyopathy and may be identified by Late Gadolinium Enhancement (LGE) MRI. While associated with future cardiovascular events in Hypertrophic Cardiomyopathy (HCM) and Dilated Cardiomyopathy (DCM) the influence of MF on interim quality of life (QOL) has not been explored. In this study we investigate for associations between MF and validated indices of QOL in patients with HCM and DCM. Ninety-eight patients with known cardiomyopathy (n = 56-HCM/n = 42-DCM) underwent LGE-MRI in addition to standardized testing for QOL using the disease-specific Minnesota Living With Heart Failure (MLWHF) and the generic SF-12 questionnaires. LGE-MRI images were blindly analyzed for the presence and volume of MF using validated techniques. All analyses were stratified according to cardiomyopathy sub-type. The mean age of the population was 56.8 ± 12.9 years. MF was identified in 82 % of patients with HCM and 74 % of patients with DCM with respective mean MF burdens of 20.0 and 13.7 % of the left ventricular mass (p = 0.008). QOL scores for those with HCM or DCM, as assessed by both MLWHF and SF-12, were not significantly different between those with versus those without MF, and showed no association with MF burden by quantitative signal analysis. In this study we identified no association between QOL and MF burden by LGE-MRI in patients with HCM or DCM. Therefore, the severity of underlying myocardial tissue disease, a recognized substrate for ventricular arrhythmia, cannot and should not be inferred from the patient’s symptom status or QOL.     

心脏磁共振成像预测酒精性心肌病心力衰竭患者心脏不良事件

目的 探讨心脏磁共振（CMR）心肌对比剂延迟强化（LGE）对酒精性心肌病（ACM）心力衰竭患者心脏不良事件的预测能力。方法 纳入临床诊断为ACM并出现心力衰竭症状的患者58例,对所有患者行CMR,根据是否出现LGE将患者分为LGE（+）组和LGE（-）组。对所有患者进行随访,随访终点定义为发生心脏不良事件,对两组患者随访期间出现的心脏不良事件进行生存分析;将LGE、左心室舒张末期容积、左心室收缩末期容积、左心室射血分数、左心室心肌质量指数、心力衰竭出现时间、饮酒时间纳入多因素Cox比例风险模型,分析心脏不良事件的预测因子。结果 LGE（+）组22例,LGE（-）组36例,共10例发生心脏不良事件,LGE（+）组发生率[31.82%(7/22)]显著高于LGE（-）组[8.33%(3/36),P=0.02]。LGE是心脏不良事件的强预测因子（风险比值：5.74, P=0.02）。结论 CMR心肌LGE是出现心力衰竭症状的ACM患者不良心脏事件的强预测因子。     

Myocardial SPECT perfusion defect size compared to infarct size by delayed gadolinium-enhanced magnetic resonance imaging in patients with acute or chronic infarction

BACKGROUND: Single photon emission computed tomography (SPECT) perfusion imaging has been considered a reference method for non-invasive estimation of infarct size in man. Recently, delayed gadolinium-enhanced magnetic resonance imaging (DE-MRI) has evolved as an accurate tool to quantify infarct size. Therefore, the present study was designed to compare perfusion defect size by SPECT to hyperenhanced volume by DE-MRI. METHODS: DE-MRI was performed in 30 patients. Fourteen were patients with revascularized first-time acute infarctions, eight revascularized chronic infarctions, and eight clinically referred non-revascularized patients. SPECT was performed in the same patients and analysed by a commercial package. RESULTS: The hypoperfused volume by SPECT was larger than the hyperenhanced volume by DE-MRI by 8 +/- 8 ml (6% +/- 5 percentage points), 10 +/- 18 ml (6% +/- 11 percentage points), and 26 +/- 30 ml (12% +/- 10 percentage points) in the acute, chronic and clinical populations, respectively. Left ventricle wall volume was smaller by SPECT in all settings. CONCLUSION: The SPECT perfusion defect size was comparable with but generally slightly larger than the hyperenhanced volume by DE-MRI in both absolute and relative terms in patients with acute and chronic infarction. The results may be related to systematic differences between modalities but could also be influenced by biological phenomena such as wall thinning or hypoperfused but viable myocardium.