Abnormal Sympathetic Innervation of Viable Myocardium and the Substrate of Ventricular Tachycardia After Myocardial Infarction Tetsuo Sasano, M. Roselle Abraham, Kuan-Cheng Chang, Hiroshi Ashikaga, ...Kevin J. Mills, Daniel P. Holt, John Hilton, Stephan G. Nekolla, Jun Dong, Albert C. Lardo, Henry Halperin, Robert F. Dannals, Eduardo Marbán, Frank M. Bengel To characterize the relationship between impaired sympathetic innervation and arrhythmia, a pig model of post-infarct ventricular tachycardia (VT) was studied with positron emission tomography and carbon-11 labeled epinephrine. Areas with reduced catecholamine retention but preserved perfusion were observed in the infarct borderzone. Those were larger in 7 animals with inducible VT at electrophysiological studies than in 4 without. Regionally, the degree of perfusion/innervation mismatch showed a significant correlation with reduced myocardial voltage and with the site of earliest VT activation. These data suggest that cardiac neuronal imaging might be useful to characterize the individual risk for ventricular arrhythmia.
PET/MRI of the Heart Rischpler, Christoph, MD; Nekolla, Stephan G., PhD, FESC; Kunze, Karl P., MSc ...
Seminars in nuclear medicine,
05/2015, Letnik:
45, Številka:
3
Journal Article
Recenzirano
Hybrid imaging devices including PET/CT and SPECT/CT have seen a great success in clinical routine, especially in the field of oncology. With the recent advent of PET/MRI scanners, expectations that ...PET/MRI would replicate that success were accordingly high. The combination of molecular imaging with a variety of very specific PET tracers and the high spatial resolution of MRI are expected to result in increased diagnostic accuracy or even in the creation of additional demands for hybrid imaging. However, as these systems have entered the market just recently, experience in the field of nuclear cardiology is limited and some applications still need to be validated. Owing to the profound technical differences between CT and MRI, which influences not only the estimation of the photon attenuation but also causes marked differences in the workflow, particularly in cardiovascular studies (such as the need for special personnel training and interaction between nuclear medicine specialists, radiologists, and physicists), the “familiarization phase” with this new technique also seems to be extended. However, the approach to study various conditions such as perfusion, viability, and atherosclerosis in a single imaging examination session using PET and MRI offers advantages. Although MRI allows for a detailed morphologic characterization of the studied tissue, PET adds the information on functional biological markers that are not (or at least not fully) measurable by MRI. Thus, this combined imaging approach will prove valuable in distinct cardiac diseases (such as myocarditis and cardiac sarcoidosis) and will offer vast research opportunities.
Myocardial perfusion imaging (MPI) with thallium 201 (201 Tl) or99m Tc based imaging agents has become a major tool for noninvasive identification of coronary artery disease (CAD). However, single ...photon emission computed tomography (SPECT) imaging with the current agents is vulnerable to artifacts associated with soft tissue attenuation, proximal gastrointestinal activity, image quality, and suboptimal sensitivity and is limited by the degree of first-pass myocardial extraction. The development of18 F-based flurpiridaz F-18 takes advantage of positron emission tomography (PET) to overcome many of the imaging issues and structural design to achieve an ideal MPI agent profile. Flurpiridaz F-18 was designed to bind to mitochondrial complex I with high affinity and demonstrates high heart uptake in multiple species with clear delineation of perfusion deficits. It exhibits rapid uptake in the myocardium, prolonged retention, and superior extraction versus flow profiles compared with201 Tl and99m Tc-sestamibi. A first in man study has established the safety and dosimetry of flurpiridaz F-18 and confirmed high sustained cardiac uptake. Subsequent studies performed in CAD patients established the dose and timing needed to detect perfusion deficits when the agent is administered under rest and stress conditions. This review compares the current preclinical and clinical data with an ideal MPI agent profile. The assessment indicates flurpiridaz F-18 represents a new generation of PET MPI agents and demonstrates significantly improved molecular and imaging characteristics.
Diagnostic Value of Contrast-Enhanced Magnetic Resonance Imaging and Single-Photon Emission Computed Tomography for Detection of Myocardial Necrosis Early After Acute Myocardial Infarction Tareq ...Ibrahim, Hubertus P. Bülow, Thomas Hackl, Mira Hörnke, Stephan G. Nekolla, Martin Breuer, Albert Schömig, Markus Schwaiger This study sought to investigate the diagnostic value of contrast-enhanced magnetic resonance imaging (CMR) and single-photon emission computed tomography (SPECT) in 78 patients with acute myocardial infarction (AMI). The overall sensitivity of CMR was superior to SPECT for detection of AMI (97% vs. 87%, p = 0.008) because CMR detected small myocardial infarcts that were missed by SPECT. While CMR offered a high sensitivity for detection of AMI independent of infarct-related artery, SPECT was less sensitive particularly within the left circumflex artery territory. Thus, CMR may help overcome limitations of SPECT imaging and is attractive for the accurate detection and assessment of myocardial infarct region in patients with AMI.
Abstract Background In patients with chronic angina-like chest pain, the probability of coronary artery disease (CAD) is estimated by symptoms, age, and sex according to the Genders clinical model. ...We investigated the incremental value of circulating biomarkers over the Genders model to predict functionally significant CAD in patients with chronic chest pain. Methods In 527 patients (60.4 years, standard deviation, 8.9 years; 61.3% male participants) enrolled in the European Ev aluation of In tegrated Cardiac I maging (EVINCI) study, clinical and biohumoral data were collected. Results Functionally significant CAD—ie, obstructive coronary disease seen at invasive angiography causing myocardial ischemia at stress imaging or associated with reduced fractional flow reserve (FFR < 0.8), or both—was present in 15.2% of patients. High-density lipoprotein (HDL) cholesterol, aspartate aminotransferase (AST) levels, and high-sensitivity C-reactive protein (hs-CRP) were the only independent predictors of disease among 31 biomarkers analyzed. The model integrating these biohumoral markers with clinical variables outperformed the Genders model by receiver operating characteristic curve (ROC) (area under the curve AUC, 0.70 standard error (SE), 0.03 vs 0.58 SE, 0.03, respectively, P < 0.001) and reclassification analysis (net reclassification improvement, 0.15 SE, 0.07; P = 0.04). Cross-validation of the ROC analysis confirmed the discrimination ability of the new model (AUC, 0.66). As many as 56% of patients who were assigned to a higher pretest probability by the Genders model were correctly reassigned to a low probability class (< 15%) by the new integrated model. Conclusions The Genders model has a low accuracy for predicting functionally significant CAD. A new model integrating HDL cholesterol, AST, and hs-CRP levels with common clinical variables has a higher predictive accuracy for functionally significant CAD and allows the reclassification of patients from an intermediate/high to a low pretest likelihood of CAD.
PET/MR Imaging in Heart Disease Rischpler, Christoph; Nekolla, Stephan G
PET clinics,
10/2016, Letnik:
11, Številka:
4
Journal Article
Hybrid PET/MR imaging is a complex imaging modality that has raised high expectations not only for oncological and neurologic imaging applications, but also for cardiac imaging applications. ...Initially, physicians and physicists had to become accustomed to technical challenges including attenuation correction, gating, and more complex workflow and more elaborate image analysis as compared with PET/CT or standalone MR imaging. PET/MR imaging seems to be particularly valuable to assess inflammatory myocardial diseases (such as sarcoidosis), to cross-validate PET versus MR imaging data (eg, myocardial perfusion imaging), and to help validate novel biomarkers of various disease states (eg, postinfarction inflammation).
Image quality in PET examinations is influenced by several factors. Patient motion during PET data acquisition is a substantial problem that potentially leads to smearing artifacts, resulting in the ...loss of diagnostic accuracy both in visual and quantitative image analyses. In hybrid imaging, coregistration of functional (PET) and morphologic (CT or MR imaging) data can be hampered by patient movement between the acquisitions, resulting in additional sources of error. This article describes the artifacts due to patient movement.
Electrocardiogram-gated cardiac positron emission tomography is a valuable addition to the armamentarium of clinical positron emission tomography. It provides incremental diagnostic information and ...can be conveniently embedded into clinical protocols. In the same way electrocardiogram gating was added to myocardial perfusion single photon emission computed tomography, it can be expected that this approach will be a standard component in the future.
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