Dali Feng

Mayo Clinic - Rochester, Rochester, Minnesota, United States

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Publications (13)71.71 Total impact

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    ABSTRACT: Echocardiography is one of the most important clinical tools in the diagnosis and management of various pericardial diseases, including constrictive pericarditis, effusive constrictive pericarditis, pericardial effusion, tamponade, absence of the pericardium and cysts or tumors. During recent years, remarkable progress has been made in echocardiography: cardiac tissue Doppler analysis (TDI), strain and strain rate imaging by speckle tracking imaging (STE) and three-dimensional (3D) echocardiography. The assessment of early diastolic annulus velocity and annulus reversus by TDI improves the differentiation of constriction from restrictive myocardial disease, which can be further facilitated by STE as a complementary tool. 3D echocardiography may be useful for the more precise assessment of pericardial diseases, such as pericardial effusion or pericardial masses as it provides incremental value to 2D echocardiography by detecting anatomic structures with higher accuracy. Applications of these newer echocardiographic techniques in the assessment of pericardial diseases are discussed in this chapter.
    Heart Failure Reviews 07/2012; 18(3). DOI:10.1007/s10741-012-9325-z · 3.99 Impact Factor
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    Dali Feng, Kyle Klarich, Jae K. Oh
    Amyloidosis - An Insight to Disease of Systems and Novel Therapies, 11/2011; , ISBN: 978-953-307-795-6
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    ABSTRACT: Constrictive pericarditis (CP) is a disabling disease, and usually requires pericardiectomy to relieve heart failure. Reversible CP has been described, but there is no known method to predict the reversibility. Pericardial inflammation may be a marker for reversibility. As a pilot study, we assessed whether cardiac magnetic resonance imaging pericardial late gadolinium enhancement (LGE) and inflammatory biomarkers could predict the reversibility of CP after antiinflammatory therapy. Twenty-nine CP patients received antiinflammatory medications after cardiac magnetic resonance imaging. Fourteen patients had resolution of CP, whereas 15 patients had persistent CP after 13 months of follow-up. Baseline LGE pericardial thickness was greater in the group with reversible CP than in the persistent CP group (4 ± 1 versus 2 ± 1 mm, P = 0.001). Qualitative intensity of pericardial LGE was moderate or severe in 93% of the group with reversible CP and in 33% of the persistent CP group (P = 0.002). Cardiac magnetic resonance imaging LGE pericardial thickness ≥ 3 mm had 86% sensitivity and 80% specificity to predict CP reversibility. The group with reversible CP also had higher baseline C-reactive protein and erythrocyte sedimentation rate than the persistent CP group (59 ± 52 versus 12 ± 14 mg/L, P = 0.04 and 49 ± 25 versus 15 ± 16 mm/h, P = 0.04, respectively). Antiinflammatory therapy was associated with a reduction in C-reactive protein, erythrocyte sedimentation rate, and pericardial LGE in the group with reversible CP but not in the persistent CP group. Reversible CP was associated with pericardial and systemic inflammation. Antiinflammatory therapy was associated with a reduction in pericardial and systemic inflammation and LGE pericardial thickness, with resolution of CP physiology and symptoms. Further studies in a larger number of patients are needed.
    Circulation 10/2011; 124(17):1830-7. DOI:10.1161/CIRCULATIONAHA.111.026070 · 14.95 Impact Factor
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    ABSTRACT: Left atrial ablation is increasingly used to treat patients with symptomatic atrial fibrillation (AF). Prior to ablation, exclusion of left atrial appendage (LAA) thrombus is important. Whether ECG-gated dual-source computed tomography (DSCT) provides a sensitive means of detecting LAA thrombus in patients undergoing percutaneous AF ablation is unknown. Thus, we sought to determine the utility of ECG-gated DSCT in detecting LAA thrombus in patients with AF. A total of 255 patients (age 58 ± 11 years, 78% male, ejection fraction 58 ± 9%) who underwent ECG-gated DSCT and transesophageal echocardiography (TEE) prior to AF ablation between February 2006 and October 2007 were included. CHADS2 score and demographic data were obtained prospectively. Gated DSCT images were independently reviewed by two cardiac imagers blinded to TEE findings. The LAA was either defined as normal (fully opacified) or abnormal (under-filled) by DSCT. An under-filled LAA was identified in 33 patients (12.9%), of whom four had thrombus confirmed by TEE. All patients diagnosed with LAA thrombus using TEE also had an abnormal LAA by gated DSCT. Thus, sensitivity and specificity for gated DSCT were 100% and 88%, respectively. No cases of LAA filling defects were observed in patients <51 years old with a CHADS2 of 0. In patients referred for AF ablation, thrombus is uncommon in the absence of additional risk factors. Gated DSCT provides excellent sensitivity for the detection of thrombus. Thus, in AF patients with a CHADS2 of 0, gated DSCT may provide a useful stand-alone imaging modality.
    Journal of Interventional Cardiac Electrophysiology 11/2010; 29(2):75-81. DOI:10.1007/s10840-010-9505-5 · 1.55 Impact Factor
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    ABSTRACT: Our aim was to evaluate the role and mechanism of late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) in identifying cardiac amyloidosis (CA) and to investigate associations between LGE and clinical, morphologic, functional, and biochemical features. CA can be challenging to diagnose by echocardiography. Recent studies have demonstrated an emerging role for LGE-CMR. LGE-CMR was performed in 120 patients with amyloidosis. Cardiac histology was available in 35 patients. The remaining 85 patients were divided into those with and without echocardiographic evidence of CA. Of the 35 patients with histologically verified CA, abnormal LGE was present in 34 (97%) patients and increased echocardiographic left ventricular wall thickness in 32 (91%) patients. Global transmural or subendocardial LGE (83%) was most common and was associated with greater interstitial amyloid deposition (p = 0.03). Suboptimal myocardial nulling (8%) and patchy focal LGE (6%) were also observed. LGE distribution matched the deposition pattern of interstitial amyloid. Among patients without cardiac histology, LGE was present in 86% of those with evidence of CA by echocardiography and in 47% of those without evidence of CA by echocardiography. In patients without echocardiographic evidence of CA, the presence of LGE was associated with worse clinical, electrocardiographic (ECG), and cardiac biomarker profiles. In all patients, LGE presence and pattern was associated with New York Heart Association functional class, ECG voltage, left ventricular mass index, right ventricular wall thickness, troponin-T, and B-type natriuretic peptide levels. LGE is common in CA and detects interstitial expansion from amyloid deposition. Global transmural or subendocardial LGE is most common, but suboptimal myocardial nulling and focal patchy LGE are also observed. LGE-CMR may detect early cardiac abnormalities in patients with amyloidosis with normal left ventricular thickness. The presence and pattern of LGE is strongly associated with clinical, morphologic, functional, and biochemical markers of prognosis.
    JACC. Cardiovascular imaging 02/2010; 3(2):155-64. DOI:10.1016/j.jcmg.2009.09.023 · 6.99 Impact Factor
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    ABSTRACT: Primary amyloidosis has a poor prognosis as a result of frequent cardiac involvement. We recently reported a high prevalence of intracardiac thrombus in cardiac amyloid patients at autopsy. However, neither the prevalence nor the effect of anticoagulation on intracardiac thrombus has been evaluated antemortem. We studied all transthoracic and transesophageal echocardiograms of cardiac amyloid patients at the Mayo Clinic. The prevalence of intracardiac thrombosis, clinical and transthoracic/transesophageal echocardiographic risks for intracardiac thrombosis, and effect of anticoagulation were investigated. We identified 156 patients with cardiac amyloidosis who underwent transesophageal echocardiograms. Amyloidosis was the primary type (AL) in 80; other types occurred in 76 patients, including 56 with the wild transthyretin type, 17 with the mutant transthyretin type, and 3 with the secondary type. Fifth-eight intracardiac thrombi were identified in 42 patients (27%). AL amyloid had more frequent intracardiac thrombus than the other types (35% versus 18%; P=0.02), although the AL patients were younger and had less atrial fibrillation. Multivariate analysis showed that atrial fibrillation, poor left ventricular diastolic function, and lower left atrial appendage emptying velocity were independently associated with increased risk for intracardiac thrombosis, whereas anticoagulation was associated with a significantly decreased risk (odds ratio, 0.09; 95% CI, 0.01 to 0.51; P<0.006). Intracardiac thrombosis occurs frequently in cardiac amyloid patients, especially in the AL type and in those with atrial fibrillation. Risk for thrombosis increased if left ventricular diastolic dysfunction and atrial mechanical dysfunction were present. Anticoagulation therapy appears protective. Timely screening in high-risk patients may allow early detection of intracardiac thrombus. Anticoagulation should be carefully considered.
    Circulation 05/2009; 119(18):2490-7. DOI:10.1161/CIRCULATIONAHA.108.785014 · 14.95 Impact Factor
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    ABSTRACT: To assess the role of magnetic resonance imaging (MRI) in the assessment of diastolic function, diastolic mitral inflow parameters using MRI and transthoracic Doppler echocardiography (echocardiography) were compared in patients with cardiac amyloidosis. Thirty-eight patients (age 60 +/- 12 years; 32% women) in sinus rhythm with cardiac amyloidosis (biopsy-proven systemic amyloidosis and positive echocardiographic and contrast-enhanced cardiac MRI findings) were evaluated. Cine phase-contrast MRI images of mitral inflow were obtained in the left ventricle to quantify diastolic blood flow. MRI measurements of diastolic parameters were compared (Spearman's rank correlation) with echocardiographic diastolic mitral inflow velocity parameters. Additional analysis was performed comparing MRI findings in patients with a restrictive echocardiographic diastolic filling pattern (n = 23) versus those without (n = 15). For the 38 patients, early diastolic (E) peak velocity was 61 +/- 26 cm/s using MRI versus 79 +/- 21 using echocardiography (Spearman's rank correlation 0.55, p = 0.0004), and late diastolic (A) peak velocity was 46 +/- 22 cm/s using MRI versus 47 +/- 22 cm/s using echocardiography (Spearman's rank correlation 0.54, p = 0.0005). E/A ratio was 1.55 +/- 0.9 using MRI and 2.25 +/- 1.4 using echocardiography (Spearman's rank correlation 0.75, p <0.0001). Deceleration times in both modalities showed good correlation (MRI, 180 +/- 44 ms vs echocardiography, 179 +/- 49; Spearman's rank correlation 0.61, p = 0.0001). MRI E/A ratio for peak velocities was significantly higher in patients with restrictive echocardiographic patterns (1.95 +/- 1.0) versus those without (0.93 +/- 0.3; p = 0.0003). Two of 23 patients with a restrictive echocardiographic pattern had an MRI E/A ratio <1. In conclusion, mitral inflow peak velocities, deceleration times, and E/A ratios detected using phase-contrast MRI in patients with cardiac amyloidosis showed moderately good correlation with echocardiography and identified most patients with restrictive echocardiographic patterns.
    The American journal of cardiology 04/2009; 103(5):718-23. DOI:10.1016/j.amjcard.2008.10.039 · 3.43 Impact Factor
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    ABSTRACT: The aim of this study was to determine whether multidetector computed tomography (MDCT) is able to exclude left atrial appendage (LAA) thrombus in patients referred for catheter ablation of atrial fibrillation (CAAF). MDCT is commonly used to render pulmonary vein and left atrial anatomy before CAAF. Transesophageal echocardiography (TEE) is also often performed before the ablation to exclude LAA thrombus. Whether MDCT alone is sufficient to exclude LAA thrombus is unknown. Patients referred for CAAF at the Mayo Clinic between March 2004 and October 2006 were included. Clinical data, 64-slice MDCT (nonelectrocardiography-gated), and TEE were all analyzed. Image data were independently reviewed by 2 cardiac radiologists blinded to the TEE findings. The appearance of the LAA was defined as normal (fully opacified) or abnormal (underfilled). Four hundred two patients (mean age 56 +/- 10 years; 76% male; ejection fraction 56 +/- 10%) were included. Three hundred sixty-two had no evidence of a filling defect by ungated MDCT or left atrial spontaneous echo contrast or thrombus by TEE. In 40 patients, the LAA was "underfilled" with 9 definite thrombi confirmed by TEE. Sensitivity and specificity was 100% and 92%, respectively, with a negative predictive value of 100% and positive predictive value of 23%. In patients with LAA underfilling, Doppler-derived LAA emptying velocities were substantially reduced (mean 19 cm/s; range 6 to 61 cm/s) below the normal range. A higher CHADS(2) (congestive heart failure, hypertension, age older than 75 years, and diabetes) score (1.6 vs. 1.1) was observed in patients with LAA filling defects. No cases of LAA thrombus were observed in patients age <52 years with CHADS(2) score <1. In patients referred for CAAF, MDCT is a sensitive (100% sensitivity) imaging modality that could be used alone especially in patients age <52 years with a CHADS(2) score <1. Incorporation of these findings could decrease the need for multiple imaging modalities and thereby reduce cost of the procedure.
    JACC. Cardiovascular imaging 02/2009; 2(1):69-76. DOI:10.1016/j.jcmg.2008.09.011 · 6.99 Impact Factor
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    ABSTRACT: Imaging of the pericardium requires understanding of anatomy and the normal and abnormal physiology of the pericardium. MR imaging is well-suited for answering clinical questions regarding suspected pericardial disease. Pericardial diseases that may be effectively imaged with MR imaging include pericarditis, pericardial effusion, cardiac-pericardial tamponade, constrictive pericarditis, pericardial cysts, absence of the pericardium, and pericardial masses. Although benign and malignant primary tumors of the pericardium may be occasionally encountered, the most common etiology of a pericardial mass is metastatic disease.
    Magnetic Resonance Imaging Clinics of North America 06/2008; 16(2):185-99, vii. DOI:10.1016/j.mric.2008.02.011 · 0.80 Impact Factor
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    ABSTRACT: Cardiac MR imaging is the preferred method for assessment of cardiac masses. A comprehensive cardiac MR imaging examination for a cardiac mass consists of static morphologic images using fast spin-echo sequences, including single-shot techniques, with T1 and T2 weighting and fat suppression pulses as well as dynamic imaging with cine steady-state free precession techniques. Further tissue characterization is provided with perfusion and delayed enhancement imaging. Specific cardiac tumoral characterization is possible in many cases. When specific tumor characterization is not possible, MR imaging often can demonstrate aggressive versus nonaggressive features that help in differentiating malignant from benign tumors.
    Magnetic Resonance Imaging Clinics of North America 06/2008; 16(2):137-64, vii. DOI:10.1016/j.mric.2008.02.009 · 0.80 Impact Factor
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    ABSTRACT: Apical Ballooning Syndrome (ABS) is a novel acute cardiac syndrome that mimics acute myocardial infarction (AMI). This study evaluates the diagnostic utility of cardiac magnetic resonance imaging (CMR) in patients with suspected ABS. Contrast-enhanced CMR was performed in 13 consecutive patients with suspected ABS on the basis of their initial clinical presentation and cardiac catheterization results. Ten patients (all female, mean age 71 +/- 8 years) had an eventual diagnosis of ABS. CMR demonstrated left ventricle regional wall motion abnormalities (RWMA) involving the apex and mid-ventricle. Six also had right ventricular apical akinesis. There was no myocardial delayed enhancement (MDE) in these patients. The remaining three patients had initial features suggestive of ABS but were eventually determined to have AMI. Left ventriculography showed typical apical ballooning that was not explained by coronary angiography results. Two had MDE and persistent RWMA consistent with anterior AMI. One had RWMA on CMR consistent with a single vascular territory, and subsequent intravascular ultrasound showed obstructive plaque in the left anterior descending (LAD) artery. The final diagnosis in these patients was AMI with clot lysis prior to coronary angiography. While ABS mimics AMI, AMI with spontaneous clot lysis may also mimic ABS, and at least in some patients, be mistaken for ABS. ABS is characterized by the absence of MDE and complete myocardial viability on CMR. The diagnosis of ABS can be excluded if CMR demonstrates MDE consistent with myocardial necrosis in a pattern and distribution consistent with AMI.
    The International Journal of Cardiovascular Imaging 06/2008; 24(8):875-82. DOI:10.1007/s10554-008-9320-6 · 2.32 Impact Factor
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    ABSTRACT: PURPOSE Bicuspid aortic valve (BAV) is a common congenital abnormality. The diagnosis is usually made by echocardiography. The ability of cardiac MRI to accurately identify BAV or a comparison with echocardiography has not been reported. METHOD AND MATERIALS A series of 53 patients with a diagnosis of BAV (n=43) or possible BAV (n=9) after transthoracic echocardiography (TTE) or a trileaflet aortic valve on TTE that was later categorized as BAV by TEE (n=1), as well as 20 control patients with a trileaflet valve subsequently underwent MRI with accurate positioning of the imaging plane perpendicular to the valve leaflets to evaluate valve morphology. Both steady-state free precession (SSFP) and cine-phase contrast images were obtained. RESULTS Cardiac MRI identified the presence of BAV in all 43 patients with a similar diagnosis by TTE. Of these, 24 patients underwent surgery or TEE which confirmed BAV. In the 9 patients with possible BAV by TTE, MRI identified 5 with BAV and 4 with a trileaflet valve. Three of the 9 patients underwent subsequent TEE/surgery with confirmation of the MRI diagnosis (1 BAV, 2 trileaflet). One patient was incorrectly thought to have a trileaflet valve on TTE, but both TEE and MRI confirmed a BAV. Accurate identification of valve cusp fusion was possible in all cases with right-left cusp fusion in 39 (80%), right-noncoronary fusion in 8 (16%), and left-noncoronary fusion in 2 (4%). MRI correctly identified a trileaflet aortic valve in all 20 control patients. When considering those patients with surgical confirmation, MRI had 100% sensitivity and 100% specificity for diagnosing BAV. CONCLUSION Cardiac MRI is a highly accurate modality for the identification of BAV with uniformly good spatial resolution. It may be especially helpful in confirming the diagnosis of BAV when TTE assessment is hindered by inadequate acoustic windows. In these cases it may be a non-invasive alternative to TEE, and allows for concomitant evaluation for associated conditions such as ascending aortic dilatation/aortic coarctation. CLINICAL RELEVANCE/APPLICATION This is the first comparison of Cardiac MRI with echocardiography for the identification of bicuspid aortic valve, and demonstrates high accuracy for this modality.
    Radiological Society of North America 2007 Scientific Assembly and Annual Meeting; 11/2007
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    ABSTRACT: Patients with primary amyloidosis (AL type) have a poor prognosis, in part due to frequent cardiac involvement. Although intracardiac thrombus has been reported in anecdotal cases, neither its frequency nor its role in causing mortality is known. Furthermore, the clinical and echocardiographic variables that may be associated with thromboembolism in cardiac amyloidosis have not been defined. A total of 116 autopsy or explanted cases of cardiac amyloidosis (55 AL and 61 other type) were identified in the Mayo Clinic. Forty-six fatal nonamyloid trauma cases served as controls. Each heart was examined for intracardiac thrombus. The cause of death was determined from autopsy and clinical notes. Intracardiac thrombosis was identified in 38 hearts (33%). Twenty-three had 1 thrombus, whereas 15 had 2 to 5 thrombi. Although subjects in the AL group were younger and had less atrial fibrillation than those with other types of amyloidosis, the AL group had significantly more intracardiac thrombus (51% versus 16%, P<0.001) and more fatal embolic events (26% versus 8%, P<0.03). Control hearts had no intracardiac thrombus. The presence of both atrial fibrillation and AL was associated with an extremely high risk for thromboembolism (odds ratio 55.0 [95% confidence interval 8.1 to 1131.4]). By multivariate analysis, AL type (odds ratio 8.4 [95% confidence interval 1.8 to 51.2]) and left ventricular diastolic dysfunction (odds ratio 12.2 [95% confidence interval 2.7 to 72.7]) were independently associated with thromboembolism. A high frequency of intracardiac thrombosis was present in cardiac amyloidosis. Furthermore, thromboembolism caused significant fatality. Several risk factors for thromboembolism were identified. Early screening, especially in high-risk patients, and early anticoagulation might reduce morbidity and mortality.
    Circulation 11/2007; 116(21):2420-6. DOI:10.1161/CIRCULATIONAHA.107.697763 · 14.95 Impact Factor