Changes in right ventricular function measured by cardiac magnetic resonance imaging in patients receiving pulmonary arterial hypertension-targeted therapy: the EURO-MR study.

BACKGROUND: Most measures that predict survival in pulmonary hypertension (PH) relate directly to, or correlate with, right ventricular (RV) function. Direct assessment of RV function using noninvasive techniques such as cardiac MRI may therefore be an appropriate way of determining response to therapy and monitoring disease progression in PH. METHODS AND RESULTS: In this pan-European study, 91 patients with PH (mean pulmonary arterial pressure 46±15 mm Hg) underwent clinical and cardiac MRI assessments at baseline and after 12 months of disease-targeted therapy (predominantly endothelin receptor antagonists [47.3%] or phosphodiesterase type-5 inhibitors [25.3%]). At month 12, functional class had improved in 21 patients, was unchanged in 63 patients, and had deteriorated in 7 patients. Significant improvements were achieved in RV and left ventricular ejection fraction (P<0.001 and P=0.0007, respectively), RV stroke volume index (P<0.0001), and left ventricular end-diastolic volume index (P=0.0015). Increases in 6-minute walk distance were significant (P<0.0001) and correlated with change in RV ejection fraction and left ventricular end-diastolic volume, although correlation coefficients were low (r=0.28, P=0.01 and r=0.26, P=0.02, respectively). CONCLUSIONS: On-treatment changes in cardiac MRI-derived variables from left and right sides of the heart reflected changes in functional class and survival in patients with PH. Direct measurement of RV function using cardiac MRI can fully assess potential benefits of treatment in PH.

Myocardial oedema as the sole marker of acute injury in Takotsubo cardiomyopathy: a cardiovascular magnetic resonance (CMR) study.

PURPOSE: The main hallmark of Takotsubo cardiomyopathy (TT-CMP) is transient ischaemia, with completely reversible regional contractile dysfunction, which involves the mid-apical segments and shows no angiographic signs of coronary artery disease (CAD). The acute and reversible myocardial injury suggests that tissue oedema may be an important marker of disease. MATERIALS AND METHODS: Seventeen patients with a clinical and angiographic diagnosis of TT-CMP underwent cardiovascular magnetic resonance (CMR) imaging in the acute phase and at follow-up after 4 months. A standard acquisition protocol including turbo spin echo (TSE) T2-weighted short-tau inversion-recovery (T2 STIR), steady-state free-precession cine (SSFP cine) and lateenhancement (LE) imaging after gadolinium benzyloxypropionic tetraacetic acid (Gd-BOPTA) administration was performed. All images were analysed, and data on oedema and LE were correlated with regional dysfunction and histological findings from endomyocardial biopsy (EMB) where available. RESULTS: In all patients, T2 STIR images showed a diffuse homogeneous hyperintensity that extended to all mid-apical segments and perfectly matched the area of regional dysfunction, reflecting tissue oedema. In the five patients who underwent EMB, histology confirmed the massive interstitial oedema associated with typical contraction-band necrosis. No cases of LE were observed. At follow-up, complete regression of oedema was observed in all cases, with significant recovery of regional and global left ventricular (LV) function (ejection fraction from 48.7% to 59.8%). CONCLUSIONS: Myocardial oedema on CMR is a characteristic feature of acute TT-CMP, which reflects acute inflammation and acute myocardial injury. It could therefore be used as a specific marker of disease severity.

Relationship between location and size of myocardial infarction and their reciprocal influences on post-infarction left ventricular remodelling.

AIMS: To assess the intricate relationship between myocardial infarction (MI) location and size and their reciprocal influences on post-infarction left ventricular (LV) remodelling. METHODS AND RESULTS: A cohort of 260 reperfused ST-segment elevation MI patients was prospectively studied with cardiovascular magnetic resonance at 1 week (baseline) and 4 months (follow-up). Area at risk (AAR) and MI size were quantified by T2-weighted and late-gadolinium enhancement imaging, respectively. Adverse LV remodelling was defined as an increase in LV end-systolic volume ≥15% at follow-up. One hundred and twenty-seven (49%) patients had anterior MI and 133 (51%) patients had non-anterior MI. Although the degree of myocardial salvage was similar between groups (P = 0.74), anterior MI patients had larger AAR and MI size than non-anterior MI patients yielding worse regional and global LV function at baseline and follow-up. At univariable analysis, anterior MI was associated with increased risk of adverse LV remodelling (P = 0.017) and lower LV ejection fraction (EF) at follow-up (P = 0.001), but not when accounted for baseline MI size. Accordingly, at multivariable analysis, baseline MI size but not its location was an independent predictor of adverse LV remodelling (odds ratio = 1.061, P < 0.001) and EF at follow-up (ß-coefficient = -0.255, P < 0.001). CONCLUSION: Anterior MI patients experience more pronounced post-infarction LV remodelling and dysfunction than non-anterior MI patients due to a greater magnitude of irreversible ischaemic LV damage without any independent contribution of MI location.

Optimizing radiation dose and image quality.

Radiation exposure is a critical issue in multidetector CT (MDCT) particularly since fast MDCT scanners have become widely available, and the method has been proposed as a noninvasive diagnostic tool for an increasing number of clinical applications. Additional features of MDCT imaging affecting individual dose are related to the inappropriate use of scanners caused by practices such as scanning beyond the area of interest or acquiring unnecessary multiphase image sets. In order to reduce individual exposure and in accordance with the ALARA principle, several strategies have been implemented over the last few years which are based on X-ray emission or optimization of scanning parameters (i.e. mAs, kV, pitch, collimation) or which take account of the individual patient's characteristics (automatic exposure control systems and ECG-pulsing techniques for ECG-gated acquisitions). These strategies allow optimization of image quality while keeping individual exposure at the lowest level. We review here these different strategies taking into account the relationship between image noise and different scanning parameters. Data from the literature are discussed, and current technological developments are considered, including initial results of dual source and SnapShot pulse technologies which have been shown to result in a significant dose reduction in ECG-gated cardiac acquisitions without compromising image quality.