These preliminary observations suggest that elective, nonsurgical insertion of an endovascular stent-graft is safe and efficacious in selected patients who have thoracic aortic dissection and for whom surgery is indicated. Endoluminal repair may be useful for interventional reconstruction of thoracic aortic dissection.
Background-Because ischemically injured myocardium is frequently composed of viable and nonviable portions, a method to discriminate the two is useful for clinical management. Methods and Results-Ischemically injured myocardium was characterized with extracellular nonspecific (Gd-DTPA) and necrosis-specific (mesoporphyrin) MR contrast media in rats. Relaxation rates (R1) were measured on day 1 and day 2 by inversion-recovery echoplanar imaging. Spin-echo imaging was used to define contrast-enhanced regions and regional wall thickening. Gadolinium concentration, area at risk, and infarct size were measured at postmortem examination. ⌬R1 ratio (⌬R1 myocardium /⌬R1 blood ) after administration of Gd-DTPA was greater in ischemically injured myocardium (1.20Ϯ0.15) than in normal myocardium (0.47Ϯ0.05, PϽ0.05), which was attributed to differences in gadolinium concentration and water content. The Gd-DTPA-enhanced region on day 2 was larger (32.8Ϯ0.9%) than true infarction as demonstrated by triphenyltetrazolium chloride (TTC) (24.6Ϯ1.4%, PϽ0.001, rϭ0.21). Bland-Altman analysis revealed that the Gd-DTPA-enhanced region overestimated true infarct size by 7.8Ϯ5.9%. On the other hand, the mesoporphyrin-enhanced region (26.9Ϯ1.8%, PϭNS, rϭ0.87) and true infarct size were identical. The difference in the areas demarcated by the 2 agents is the peri-infarction. Systolic and diastolic MR images revealed no wall thickening in the mesoporphyrin-enhanced region (0.3Ϯ3.3%) but reduced thickening in the Gd-DTPA-enhanced rim (8.5Ϯ5.5%, PϽ0.05). Conclusions-The Gd-DTPA-enhanced region encompasses both viable and nonviable portions of the ischemically injured myocardium. The Gd-DTPA-enhanced area overestimated infarct size, but the mesoporphyrin-enhanced area matched true infarct size. The salvageable peri-infarction zone can be characterized with double-contrast-enhanced and functional MR imaging; the mismatched area of enhancement between the 2 agents shows residual wall thickening.
(60%-89%), 90% (56%-100%), and 71% (48%-89%) for active myocarditis, respectively. Conclusions-T2 mapping seems to be superior when compared with standard CMR parameters, global myocardial T1, and extracellular volume fraction values for assessing the activity of myocarditis in patients with recent-onset heart failure and reduced left ventricular function. Bohnen et al T1 and T2 Mapping to Detect Active Myocarditiswith acute coronary syndrome-like presentation. 2,4 Thus, there is a need for novel diagnostic tools to identify patients with active myocarditis in patients with recent-onset HF.T1 and T2 mapping CMR are novel techniques for quantitative tissue characterization, which may overcome the limitations of current CMR criteria to assess diffuse myocardial injury. [6][7][8][9][10][11][12] Recent studies indicate that native myocardial T1, myocardial T2, and extracellular volume (ECV) imaging could improve the diagnostic performance of CMR. 10,12,13 However, it is currently unclear whether these novel CMR techniques have the ability to differentiate active myocarditis from myocarditis without ongoing inflammation in patients presenting with recent-onset HF. Thus, this study evaluated the performance of T1 and T2 mapping CMR to identify patients with biopsy-proven active myocarditis in patients presenting with recent-onset HF and reduced LV function. Methods Patient PopulationThe local ethics committee approved the study. All patients and control subjects gave their written informed consent. Thirty-one consecutive patients were included between March 2013 and July 2014 who met the following criteria: (1) presentation with recent-onset HF, (2) LV ejection fraction of <45% in the absence of significant coronary artery disease, and (3) clinically indicated EMB and CMR.14 This study did not include patients presenting acute coronary syndromelike or with arrhythmia, in whom EMB is not routinely performed in our institution. The median interval between onset of symptoms and presentation to our institution for diagnostic evaluation was 31 days with first (Q1) and third quartiles (Q3) of 6 and 64 days, respectively. The median interval between presentation and CMR was 3 days (Q1-Q3, 1-6 days), whereas the median interval between presentation and EMB was 10 days (Q1-Q3, 5-14 days). The major clinical characteristics of patients are presented in Table 1. Endomyocardial BiopsyIn agreement with current recommendations, at least 4 biopsies 1 to 2 mm in size were obtained from the left (n=12; 39%) or right ventricle (n=19; 61%).1 Active myocarditis with ongoing myocardial inflammation was defined by ≥14 infiltrating leukocytes/mm 2 , CD3 + and CD68+ macrophages in the presence of myocyte damage and fibrosis as described before.15-18 DNA and RNA were extracted and polymerase chain reaction/reverse transcriptase-polymerase chain reaction was performed to detect typical viruses in the samples as appropriate. [15][16][17][18] A detailed description of the sample analysis is provided in the Data Supplement. CMR ProtocolCMR was...
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