核磁共振成像与心脏起搏器的研究进展

核磁共振成像（MRI）环境可严重影响起搏器功能,从而植入心脏起搏器患者接受MRI检查成为禁忌.为了解决MRI对心脏起搏器产生的危害,MRI兼容性起搏器应运而生 现对MRI与心脏起搏器相互作用、心脏起搏器的改进及MRI兼容性起搏器的类型等方面作一阐述.     

Evaluation of the Severity of Mitral Regurgitation by the Use of Signal Void in Magnetic Resonance Imaging

Background: The study was designed to evaluate the severity of mitral regurgitation by cardiac magnetic resonance imaging (MRI). We proposed a new measurement of signal void by MRI and tried to define threshold values for the severity of regurgitation with different sequences. Methods: Twenty‐one patients with mitral regurgitation were evaluated by echocardiography and MRI. We measured the length, width, and the area of jet flow void from long‐axis and four‐chamber views. The regurgitant area was measured with TrueFISP, FLASH sequences, and phase images by tracing the signal‐void area in left atrium parallel to mitral annulus. This new parameter for grading of the severity of mitral regurgitation by cine MRI was called regurgitant area from short axis (RAFSA). Results: All methods (EROA, vena contracta) were correlated for determining the regurgitation severity (P < 0.01). There was a correlation between EROA by echocardiography and RAFSA by MRI with the TrueFISP, FLASH sequences, and phase images (P < 0.01). Stepwise regression analysis revealed that EROA was significantly correlated with RAFSA by phase images (P < 0.001). After regression analysis, threshold values of RAFSA by phase imaging were calculated and found to be 0.27 cm² and 0.92 cm² between mild, moderate, and severe mitral regurgitations (100% sensitivity, 67% specificity, and 100% sensitivity, 78% specificity, respectively) (P < 0.01, P < 0.05). Conclusions: MRI is an alternative method for evaluating mitral regurgitation. Our study suggests a new parameter, RAFSA by cine MRI, to grade the severity of mitral regurgitation and provides threshold values in order to define mild, moderate, and severe regurgitations. (ECHOCARDIOGRAPHY, Volume **, ***********)     

Safety and Outcomes of Transcatheter Closure of Patent Ductus Arteriosus in Children With Pulmonary Artery Hypertension

To investigate whether transcatheter device closure of patent ductus arteriosus (PDA) is safe in children with pulmonary artery hypertension, we retrospectively analyzed our experience with 33 patients who underwent the procedure from January 2000 through August 2015.Pulmonary artery hypertension was defined as a pulmonary vascular resistance index (PVRI) >3 WU · m². All 33 children (median age, 14.5 mo; median weight, 8.1 kg) underwent successful closure device implantation and were followed up for a median of 17.2 months (interquartile range [IQR], 1.0–63.4 mo). During catheterization, the median PVRI was 4.1 WU · m² (IQR, 3.6–5.3 WU · m²), and the median mean pulmonary artery pressure was 38.0 mmHg (IQR, 25.5–46.0 mmHg). Premature birth was associated with pulmonary vasodilator therapy at time of PDA closure ( P=0.001) but not with baseline PVRI (P=0.986). Three patients (9.1%) had device-related complications (one immediate embolization and 2 malpositions). Two of these complications involved embolization coils. Baseline pulmonary vasodilator therapy before closure was significantly associated with intensive care unit admission after closure (10/12 [83.3%] with baseline therapy vs 3/21 [14.3%] without; P <0.001). Of 11 patients receiving pulmonary vasodilators before closure and having a device in place long-term, 8 (72.7%) were weaned after closure (median, 24.0 mo [IQR, 11.0–25.0 mo]).We conclude that transcatheter PDA closure can be performed safely in many children with pulmonary artery hypertension and improve symptoms, particularly in patients born prematurely. Risk factors for adverse outcomes are multifactorial, including coil use and disease severity. Multicenter studies in larger patient populations are warranted.     

Aortopulmonary Window with Interrupted Aortic Arch and Pulmonary Artery Sling: Diagnosis by Echocardiography and Magnetic Resonance Imaging: Case Report and Literature Review

We present the pediatric case of a patient who had aortopulmonary window with interrupted aortic arch, intact ventricular septum, and pulmonary artery sling that was imaged with echocardiography and magnetic resonance imaging. This case is unique because this combination of findings has not been previously reported. The diagnosis was made without the need for angiography, and the findings were confirmed at surgery. This case shows that complex congenital heart defects can be accurately imaged by noninvasive methods.     

Important Advances in Technology and Unique Applications Related to Cardiac Magnetic Resonance Imaging

Cardiac magnetic resonance has become a well-established imaging modality and is considered the gold standard for myocardial tissue viability assessment and ventricular volumes quantification. Recent technological hardware and software advancements in magnetic resonance imaging technology have allowed the development of new methods that can improve clinical cardiovascular diagnosis and prognosis. The advent of a new generation of higher magnetic field scanners can be beneficial to various clinical applications. Also, the development of faster acquisition techniques have allowed mapping of the magnetic relaxation properties T1, T2, and T2* in the myocardium that can be used to quantify myocardial diffuse fibrosis, determine the presence of edema or inflammation, and measure iron within the myocardium, respectively. Another recent major advancement in CMR has been the introduction of three-dimension (3D) phase contrast imaging, also known as 4D flow. The following review discusses key advances in cardiac magnetic resonance technology and their potential to improve clinical cardiovascular diagnosis and outcomes.     

Serum Levels of Soluble ICAM-1 in Children with Pulmonary Artery Hypertension

This prospective cross-sectional study attempted to determine both the usefulness of the serum intercellular adhesion molecule-1 (ICAM-1) as a biomarker for pulmonary artery hypertension secondary to congenital heart disease and the nature of this marker''s association with catheter angiographic findings.Our study included a total of 70 male and female children, comprising 30 patients with both pulmonary artery hypertension and congenital heart disease, 20 patients with congenital heart disease alone, and 20 healthy control subjects. Levels of ICAM-1 in plasma samples from all groups were measured by the enzyme-linked immunosorbent assay method. Cardiac catheterization was also performed in all patients.The mean serum ICAM-1 levels in pediatric patients who had congenital heart disease with and without pulmonary artery hypertension were 349.6 ± 72.9 ng/mL and 312.3 ± 69.5 ng/mL, respectively (P=0.002). In healthy control subjects, the mean serum ICAM-1 level was 231.4 ± 60.4 ng/mL.According to the results of this study, the ICAM-1 level of the pulmonary artery hypertension group was significantly higher than those of the congenital heart disease group and the healthy control group. Correlation analysis showed that ICAM-1 level was correlated with systolic and mean pulmonary artery pressures (r=0.62, P=0.001; r=0.57, P=0.001)—which are 2 important values used in diagnosis of pulmonary artery hypertension. Moreover, receiver operating characteristic analysis yielded consistent results for the prediction of pulmonary artery hypertension. Therefore, we conclude that ICAM-1 has potential use as a biomarker for the diagnosis and follow-up of pulmonary artery hypertension.     

Dynamic Contrast Enhanced Magnetic Resonance Perfusion Imaging in High-Risk Smokers and Smoking-Related COPD: Correlations with Pulmonary Function Tests and Quantitative Computed Tomography

The study aimed to prospectively evaluate correlations between dynamic contrast-enhanced (DCE) MR perfusion imaging, pulmonary function tests (PFT) and volume quantitative CT in smokers with or without chronic obstructive pulmonary disease (COPD) and to determine the value of DCE-MR perfusion imaging and CT volumetric imaging on the assessment of smokers. According to the ATS/ERS guidelines, 51 male smokers were categorized into five groups: At risk for COPD (n = 8), mild COPD (n = 9), moderate COPD (n = 12), severe COPD (n = 10), and very severe COPD (n = 12). Maximum slope of increase (MSI), positive enhancement integral (PEI), etc. were obtained from MR perfusion data. The signal intensity ratio (R_SI) of the PDs and normal lung was calculated (R_SI = SI_PD/SI_normal). Total lung volume (TLV), total emphysema volume (TEV) and emphysema index (EI) were obtained from volumetric CT data. For “at risk for COPD,” the positive rate of PDs on MR perfusion images was higher than that of abnormal changes on non-enhanced CT images (p < 0.05). Moderate-to-strong positive correlations were found between all the PFT parameters and SI_PD, or R_SI (r range 0.445～0.683, p ≤ 0.001). TEV and EI were negatively correlated better with FEV₁/FVC than other PFT parameters (r range ?0.48 –?0.63, p < 0.001). There were significant differences in R_SI and SI_PD between “at risk for COPD” and “very severe COPD,” and between “mild COPD” and “very severe COPD”. Thus, MR perfusion imaging may be a good approach to identify early evidence of COPD and may have potential to assist in classification of COPD.     

Course of Cardiac Magnetic Resonance Imaging Findings in Acute Myocarditis after COVID-19 mRNA Vaccination

Myocarditis is being increasingly reported as a rare complication of coronavirus disease 2019 (COVID-19) mRNA vaccines. We herein report a case of myocarditis following COVID-19 mRNA vaccination in a man. Cardiac magnetic resonance imaging (CMRI) revealed an area of high signal intensity on short T1 inversion recovery (STIR) and late gadolinium enhancement (LGE), which are characteristic of myocarditis. Follow-up CMRI performed six months later revealed improvement in the myocardial edema and LGE findings. CMRI is a useful non-invasive imaging modality for making an initial diagnosis as well as for follow-up in cases of myocarditis after COVID-19 mRNA vaccination.     

Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery: Diagnoses and Surgical Results in 12 Pediatric Patients

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital condition. It responds well to early diagnosis and treatment, but otherwise the prognosis is poor. We present our case series of 12 patients (mean age, 2 ± 2.58 yr; age range, 2 mo–8 yr), emphasizing the diagnostic process and discussing our surgical results. The diagnosis of ALCAPA should be suspected in infants who have dilated cardiomyopathy with electrocardiographic changes that suggest ischemia, and in older children who have isolated mitral regurgitation. When clinical suspicion is high, the results of 2-dimensional echocardiography combined with color-flow Doppler studies in expert hands can establish the diagnosis, thus avoiding angiography in critically ill infants. The treatment of choice in our patients was transfer and reimplantation of the left coronary artery onto the ascending aorta. There were 2 deaths: both were infants in extremis who underwent emergency surgery. An older child with severe ventricular dysfunction was given mechanical ventricular assistance and then heart transplantation. As of this report, all 10 survivors remained well and asymptomatic.     

Cardiac Magnetic Resonance Imaging for the Investigation of Cardiovascular Disorders. Part 2: Emerging Applications

Cardiac magnetic resonance imaging has emerged as a robust noninvasive technique for the investigation of cardiovascular disorders. The coming-of-age of cardiac magnetic resonance—and especially its widening span of applications—has generated both excitement and uncertainty in regard to its potential clinical use and its role vis-à-vis conventional imaging techniques. The purpose of this evidence-based review is to discuss some of these issues by highlighting the current (Part 1, previously published) and emerging (Part 2) applications of cardiac magnetic resonance. Familiarity with the versatile uses of cardiac magnetic resonance will facilitate its wider clinical acceptance for improving the management of patients with cardiovascular disorders.     

Inhalant-Abuse Myocarditis Diagnosed by Cardiac Magnetic Resonance

Multiple reports of toxic myocarditis from inhalant abuse have been reported. We now report the case of a 23-year-old man found to have toxic myocarditis from inhalation of a hydrocarbon. The diagnosis was made by means of cardiac magnetic resonance imaging with delayed enhancement. The use of cardiac magnetic resonance to diagnose myocarditis has become increasingly common in clinical medicine, although there is not a universally accepted criterion for diagnosis. We appear to be the first to document a case of toxic myocarditis diagnosed by cardiac magnetic resonance. In patients with a history of drug abuse who present with clinical findings that suggest myocarditis or pericarditis, cardiac magnetic resonance can be considered to support the diagnosis.     

儿童肝脏肿瘤的影像学诊断

原发性儿童肝脏肿瘤并不罕见,儿童肝脏恶性肿瘤发生率位居儿童腹部恶性肿瘤第3位,具有恶性率高,先天性肿瘤多见和好发年龄明显的特点。而且儿童肝脏肿瘤无特异性临床表现,发病隐匿、肿瘤病灶体积大、病理类型多、发生部位复杂,与成人相比处理更为困难。对小儿肝脏肿瘤的影像诊断进行了综合阐述,指出随着影像医学的迅猛发展,影像学检查在明确肝脏肿瘤的发生部位、提示肿瘤良恶性及肿瘤分级方面具有越来越重要的参考价值。