High field MR carotid vessel wall imaging: reproducibility of five different MR-weightings

Cardiovascular Aspects of Radiolog

Regional myocardial blood flow reserve impairment and metabolic changes suggesting myocardial ischemia in patients with idiopathic dilated cardiomyopathy

AbstractOBJECTIVESWe performed positron emission tomography (PET) to evaluate myocardial ischemia in patients with idiopathic dilated cardiomyopathy (IDC).BACKGROUNDPatients with IDC have anatomically normal coronary arteries, and it has been assumed that myocardial ischemia does not occur.METHODSWe studied 22 patients with IDC and 22 control subjects using PET with nitrogen-13 ammonia to measure myocardial blood flow (MBF) at rest and during dipyridamole-induced hyperemia. To investigate glucose metabolism, fluorine-18 deoxyglucose (18FDG) was used. For imaging of oxygen consumption, carbon-11 acetate clearance rate constants (kmono) were assessed at rest and during submaximal dobutamine infusion (20 μg/kg body weight per min).RESULTSGlobal MBF reserve (dipyridamole-induced) was impaired in patients with IDC versus control subjects (1.7 ± 0.21 vs. 2.7 ± 0.10, p < 0.05). In patients with IDC, MBF reserve correlated with left ventricular (LV) systolic wall stress (r = −0.61, p = 0.01). Furthermore, in 16 of 22 patients with IDC (derived by dipyridamole perfusion) mismatch (decreased flow/increased 18FDG uptake) was observed in 17 ± 8% of the myocardium. The extent of mismatch correlated with LV systolic wall stress (r = 0.64, p = 0.02). The MBF reserve was lower in the mismatch regions than in the normal regions (1.58 ± 0.13 vs. 1.90 ± 0.18, p < 0.05). During dobutamine infusion kmonowas higher in the mismatch regions than in the normal regions (0.104 ± 0.017 vs. 0.087 ± 0.016 min−1, p < 0.05). In the mismatch regions 18FDG uptake correlated negatively with rest kmono(r = −0.65, p < 0.05), suggesting a switch from aerobic to anaerobic metabolism.CONCLUSIONSPatients with IDC have a decreased MBF reserve. In addition, low MBF reserve was paralleled by high LV systolic wall stress. These global observations were associated with substantial myocardial mismatch areas showing the lowest MBF reserves. In geographically identical regions an abnormal oxygen consumption pattern was seen together with a switch from aerobic to anaerobic metabolism. These data support the notion that regional myocardial ischemia plays a role in IDC

Reduced Left Ventricular Torsion Early After Myocardial Infarction Is Related to Left Ventricular Remodeling

Background— Left ventricular (LV) torsion is emerging as a sensitive parameter of LV systolic myocardial performance. The aim of the present study was to explore the effects of acute myocardial infarction (AMI) on LV torsion and to determine the value of LV torsion early after AMI in predicting LV remodeling at 6-month follow-up. Methods and Results— A total of 120 patients with a first ST-segment elevation AMI (mean±SD age, 59±10 years; 73% male) were included. All patients underwent primary percutaneous coronary intervention. After 48 hours, speckle-tracking echocardiography was performed to assess LV torsion; infarct size was assessed by myocardial contrast echocardiography. At 6-month follow-up, LV volumes and LV ejection fraction were reassessed to identity patients with LV remodeling (defined as a ≥15% increase in LV end-systolic volume). Compared with control subjects, peak LV torsion in AMI patients was significantly impaired (1.54±0.64°/cm vs 2.07±0.27°/cm, P <0.001). By multivariate analysis, only LV ejection fraction ( β =0.36, P <0.001) and infarct size ( β =−0.47, P <0.001) were independently associated with peak LV torsion. At 6-month follow-up, 19 patients showed LV remodeling. By multivariate analysis, only peak LV torsion (odds ratio=0.77; 95% CI, 0.65–0.92; P =0.003) and infarct size (odds ratio=1.04; 95% CI, 1.01–1.07; P =0.021) were independently related to LV remodeling. Peak LV torsion provided modest but significant incremental value over clinical, echocardiographic, and myocardial contrast echocardiography variables in predicting LV remodeling. By receiver-operating characteristics curve analysis, peak LV torsion ≤1.44°/cm provided the highest sensitivity (95%) and specificity (77%) to predict LV remodeling. Conclusions— LV torsion is significantly impaired early after AMI. The amount of impairment of LV torsion predicts LV remodeling at 6-month follow-up

Abnormal aortic wall properties in women with Turner syndrome

Background Turner syndrome (TS) is associated with aortic dilatation and dissection, but the underlying process is unclear. The aim of this study was to investigate the elastic properties and composition of the aortic wall in women with TS. Methods In this cross-sectional study, 52 women with TS aged 35 ± 13 years (50% monosomy, 12 with bicuspid aortic valve [BAV] and 4 with coarctation) were investigated using carotid-femoral pulse wave velocity (CF-PWV) by echocardiography and ascending aortic distensibility (AAD) and aortic arch pulse wave velocity (AA-PWV) by magnetic resonance imaging (MRI). As control group, 13 women with BAV without TS and 48 healthy patients were included. Results Women with TS showed a higher AA-PWV (β = 1.08, confidence interval [CI]: 0.54–1.62) after correcting for age and comorbidities compared with controls. We found no significant difference in AAD and CF-PWV. In women with TS, the presence of BAV, coarctation of the aorta, or monosomy (45, X) was not associated with aortic stiffness. In addition, aortic tissue samples were investigated with routine and immunohistochemical stains in five additional women with TS who were operated. The tissue showed more compact smooth muscle cell layers with abnormal deposition and structure of elastin and diminished or absent expression of contractile proteins desmin, actin, and caldesmon, as well as the progesterone receptor. Conclusion Both aortic arch stiffness measurements on MRI and histomorphological changes point toward an inherent abnormal thoracic aortic wall in women with TS

Comparison Between the Prognostic Value of Left Ventricular Function and Myocardial Perfusion Reserve in Patients with Ischemic Heart Disease

The purpose of this study was to compare the prognostic value of left ventricular ejection fraction (LVEF) and myocardial perfusion reserve (MPR) assessed with PET in patients with ischemic heart disease (IHD). Myocardial perfusion is the main determinant of left ventricular function in patients with IHD. The prognostic value of LVEF has been widely established. In addition, MPR determines survival in patients with hypertrophic and dilated cardiomyopathies. In the present study, we evaluated whether MPR also determines survival in patients with IHD. Methods: Between 1995 and 2003, 480 consecutive patients with chronic IHD underwent dipyridamole stress and rest (13)N-ammonia PET to determine MPR. Additionally, (18)F-FDG PET was performed for viability (mismatching defects), infarction (matching defects), and left ventricular function assessment. Patients were followed for all causes of mortality and major cardiovascular events. Results: In 463 of the 480 patients, valid MPR could be measured (368 men; mean age, 66 +/- 11 y; LVEF, 35% +/- 15%). One hundred nineteen patients underwent a PET-driven revascularization (67 through percutaneous coronary intervention and 52 through coronary artery bypass grafting). The remaining 344 patients were the subject of this study. The overall MPR was 1.71 +/- 0.50 (intertertile boundaries, 1.49 and 1.84). After adjustment for age and sex, MPR was associated with a hazard ratio for cardiac death of 4.11 (95% confidence interval, 2.98-5.67) per SD decrease, whereas the risk for LVEF was 2.76 (2.00-3.82) per SD decrease. Conclusion: Patients with IHD with a low MPR are at high risk of cardiac death. MPR is a more sensitive predictor for cardiac death than is LVEF