PET and MRI for the evaluation of regional myocardial perfusion and wall thickening after myocardial infarction

Deterioration of left ventricular (LV) function after myocardial infarction (MI) is a major cause of heart failure. Myocardial perfusion performance may play an important role in deterioration or improvement in LV function after MI. The aim of this study was to evaluate the myocardial perfusion reserve (MPR) and stress perfusion in deteriorating and non-deteriorating LV segments in patients after MI by PET and MRI, respectively. Regional wall thickening of 352 segments in 22 patients was assessed at 4 and 24 months after MI by cardiac MRI. PET was performed to evaluate MPR and adenosine stress N-13-ammonia perfusion 24 months after MI. Segments were divided into four groups according to deterioration or improvement in wall thickening. Normal functional segments at 4 months after MI that remained stable had a significantly higher mean MPR and mean stress perfusion PET value than deteriorated segments (p < 0.001). Furthermore, dysfunctional segments that improved had a significantly higher mean stress perfusion PET value than dysfunctional segments that remained dysfunctional (p < 0.001). This study demonstrated the additional value of myocardial perfusion assessment in relation to the functional integrity of the injured myocardium. Segmental functional LV improvement after MI was associated with better regional myocardial perfusion characteristics. Furthermore, the amount of wall thickening reduction was associated with regional myocardial perfusion abnormalities in patients after MI

Myocardial perfusion reserve and contractile pattern after beta-blocker therapy in patients with idiopathic dilated cardiomyopathy

In Idiopathic Dilated Cardiomyopathy (IDC) an imbalance between myocardial oxygen consumption and supply has been postulated. The ensuing subclinical myocardial ischemia may contribute to progressive deterioration of LV function. beta-blocker is the therapy of choice in these patients. However, not all patients respond to the same extent. The aim of this study was to elucidate whether differences between responders and non-responders can be identified with respect to regional myocardial perfusion reserve (MPR) and contractile performance. Patients with newly diagnosed IDC underwent Positron Emission Tomography (PET) scanning using both (13)N-ammonia as a perfusion tracer (baseline and dipyridamole stress), and (18)F-fluoro-deoxyglucose as a metabolism tracer, and a dobutamine stress MRI. MRI and PET were repeated 6 months after maximal beta-blocker therapy. MPR (assessed by PET) as well as wall motion score (WMS, assessed by MRI) were evaluated in a 17 segment-model. Functional response to beta-blocker therapy was assigned as a stable or improved LVEF or diminished LVEF. Sixteen patients were included (age 47.9 +/- A 11.5 years; 12 males, LVEF 28.6 +/- A 8.4%). Seven patients showed improved LVEF (9.7 +/- A 3.1%), and nine patients did not show improved LVEF (-3.4 +/- A 3.9%). MPR improved significantly in responders (1.56 +/- A .23 to 1.93 +/- A .49, P = .049), and MPR decreased in non-responders; however, not significantly (1.98 +/- A .70 to 1.61 +/- A .28, P = .064), but was significantly different between both groups (P = .017) after beta-blocker therapy. A significant correlation was found between change in perfusion reserve and change in LVEF: a decrease in perfusion reserve was associated with a decrease in LVEF and vice versa. Summed rest score of wall motion in responders improved from 26 to 21 (P = .022) whereas in non-responders no change was observed from 26 to 25) (P = ns). Summed stress score of wall motion in responders improved from 23 to 21 (P = .027) whereas in non-responders no change was observed from 27 to 26) (P = ns). In IDC patients, global as well as regional improvement after initiation of beta-blocker treatment is accompanied by an improvement in regional perfusion parameters. On the other hand in IDC patients with further left ventricular function deterioration after initiation of beta-blocker therapy this is accompanied by a decrease in perfusion reserve

CT angiography; useful in non-selected outpatients?

Dance has been a part of the physical education (PE) curriculum in several countries for a longtime. In spite of this, studies demonstrate that the position of dance in the subject of PE iscontested and that little time is devoted to dance. The overall aim of this article is to examine theposition of dance as a pedagogical discourse in Swedish steering documents over time. Theempirical material consists of five Swedish curricula for PE over a period of 50 years (1962–2011).Discourse analysis is used to identify organised systems of meaning, including privileged andprioritised values. Our theoretical frame of reference draws on Bernstein’s concept of codes. Threedifferent knowledge areas within dance are found in the text material: ‘dance as cultural preserver’,‘dance as bodily exercise’ and ‘dance as expression’. Three pedagogical discourses emerge fromthese knowledge areas: an identity formation discourse, a public health discourse and an aestheticdiscourse. The identity formation discourse in earlier curricula focuses on the perpetuation ofSwedish and Nordic cultural traditions, while in later curricula, it emphasises the construction of abroader multicultural identity formation related to the understanding of different cultures. Thepublic health discourse constitutes a prioritised understanding of dance as physical training relatedto a healthy lifestyle. The aesthetic discourse, which has the weakest position over time, representsthe valuing of embodied experiences and feelings expressed through movements. This discourse isclosely linked to the construction of gender. Over time, a new performance code came to surpassthe former competence code in the steering documents. The performance code positions dance inPE as mainly a physical activity with little artistic or aesthetic value. The pedagogical discourse ofdance remains within a highly disciplinary framework of social control

Ischemic patterns assessed by positron emission tomography predict adverse outcome in patients with idiopathic dilated cardiomyopathy

Although patients with idiopathic dilated cardiomyopathy (DCM) have no coronary artery disease, regional impairment of myocardial perfusion combined with preserved metabolism has been found using positron emission tomography (PET). Our aim was to assess the prognostic relevance of PET-mismatch between stress myocardial perfusion and glucose uptake on clinical outcome in DCM. In 24 patients with DCM who underwent both myocardial perfusion and metabolism PET scanning, "mismatch" was assessed and the association with clinical outcome (hospitalization, mortality, and heart transplantation) was investigated. Mismatch was found in 16 patients (66.7%). Univariate analysis showed that the presence of mismatch was associated with adverse outcome (P = 0.03). After adjustment for sex and age, the association remained significant with an adjusted relative risk of 10.4 (95% CI 1.1-103; P = 0.04) for death, heart transplant, or hospitalization. Univariate analysis also showed that a higher extent of mismatch was significantly associated with adverse outcome (P = 0.02). After adjusting for sex and age, the association remained significant with an adjusted relative risk of 6.5 [95% CI 1.2-36; P = 0.03] for death, heart transplantation, or hospitalization. PET stress perfusion-metabolism mismatch, indicative for ischemia, is frequently found in DCM patients and related to a poorer outcome

High-resolution imaging of human atherosclerotic carotid plaques with micro18F-FDG PET scanning exploring plaque vulnerability

FDG-PET can be used to identify vulnerable plaques in atherosclerotic disease. Clinical FDG-PET camera systems are restricted in terms of resolution for the visualization of detailed inflammation patterns in smaller vascular structures. The aim of the study is to evaluate the possible added value of a high-resolution microPET system in excised carotid plaques using FDG. In this study, 17 patients with planned carotid endarterectomy were included. Excised plaques were incubated in FDG and subsequently imaged with microPET. Macrophage presence in plaques was evaluated semi-quantitatively by immunohistochemistry. Plaque calcification was assessed additionally with CT and correlated to FDG uptake. Finally, FDG uptake and macrophage infiltration were compared with patient symptomatology. Heterogeneous distributions and variable intensities of FDG uptake were found within the plaques. A positive correlation between the distribution of macrophages and the FDG uptake (r = 0.68, P <.01) was found. A negative correlation was found between areas of calcifications and FDG uptake (r = -0.84, P <.001). Ratio FDG(max) values as well as degree of CD68 accumulation were significantly higher in CVA patients compared with TIA or amaurosis fugax patients (P <.05) and CVA patients compared with asymptomatic patients (P <.05). This ex vivo study demonstrates that excised carotid plaques can be visualized in detail using FDG microPET. Enhancement of clinical PET/CT resolution for similar imaging results in patients is needed

Comparison of gated PET with MRI for evaluation of left ventricular function in patients with coronary artery disease

The aim of this study was to compare left ventricular (LV) volumes and regional wall motion determined by PET with those determined by the reference technique, cardiovascular MRI. Methods: LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were measured and regional wall motion was scored in 38 patients with chronic coronary artery disease by both gated F-18-FDG PET and MRI. A 9-segment model was used for PET and MRI to assess regional wall motion. Results: Good correlations were observed between MRI and gated PET for all parameters (r values ranging from 0.91 to 0.96). With PET, there was a significant but small underestimation of LVEDV and LVEF. Mean+/-SD LVEDV, LVESV, and LVEF for MRI were 131+/-57 mL, 91+/-12 mL, and 33%+/-12%, respectively, and those for gated PET were 117+/-56 mL, 85+/-51 mL, and 30%+/-11%, respectively. For regional wall motion, an agreement of 85% was found, with a kappa-statistic of 0.79 (95% confidence interval, 0.70-0.89; SE, 0.049). Conclusion: LV volumes, LVEF, and regional wall motion can be assessed with gated F-18-FDG PET and correlate well with these parameters assessed by MRI