Introduction We aimed to assess the feasibility of SPECT and PET Y-90 imaging, and to compare these modalities by visualizing hot and cold foci in phantoms for varying isotope concentrations. Materials and methods The data was acquired from the Jaszczak and NEMA phantoms. In the Jaszczak phantom Y-90 concentrations of 0.1 MBq/ml and 0.2 MBq/ml were used, while higher concentrations, up to 1.0 MBq/ml, were simulated by acquisition time extension with respect to the standard clinical protocol of 30 sec/projection for SPECT and 30 min/bed position for PET imaging. For NEMA phantom, the hot foci had concentrations of about 4 MB/ml and the background 0.1 or 0.0 MBq/ml. All of the acquired data was analysed both qualitatively and quantitatively. Qualitative assessment was conducted by six observers asked to identify the number of visible cold or hot foci. Inter-observer agreement was assessed. Quantitative analysis included calculations of contrast and contrast-to-noise ratio (CNR), and comparisons with the qualitative results. Results For SPECT data up to two cold foci were discernible, while for PET four foci were visible. We have shown that CNR (with Rose criterion) is a good measure of foci visibility for both modalities. We also found good concordance of qualitative results for the Jaszczak phantom studies between the observers (corresponding Krippendorf’s alpha coefficients of 0.76 to 0.84). In the NEMA phantom without background activity all foci were visible in SPECT/CT images. With isotope in the background, 5 of 6 spheres were discernible (CNR of 3.0 for the smallest foci). For PET studies all hot spheres were visible, regardless of the background activity. Conclusions PET Y-90 imaging provided better results than Bremsstrahlung based SPECT imaging. This indicates that PET/CT might become the method of choice in Y-90 post radioembolization imaging for visualisation of both necrotic and hot lesions in the liver.

Although no correlation between sST2 levels and myocardial fibrosis was found, sST2 may provide some additional information about hypertrophy extension. NT-proBNP and hs-cTnT are useful biomarkers in assessment of hypertrophy and fibrosis in HCM.

Background: Left ventricular non-compaction (LVNC) is a rare cardiomyopathy typically involving the left ventricle (LV); however, the right ventricle (RV) can also be affected. This case-control study aimed to assess the morphology and function of LV and RV in children with LVNC. Methods: Sixteen children (13 ± 3 years, six girls) with LVNC were compared with 16 sex- and age-matched controls. LV and RV morphology and function were evaluated in cardiovascular magnetic resonance (CMR) studies. Additionally, LV and RV global radial (GRS), circumferential (GCS), and longitudinal strain (GLS) were assessed using tissue-tracking analysis. Results: Patients with LVNC did not differ from the healthy controls in terms of age, height, weight, and body surface area (BSA). In total, 4/16 subjects with LVNC had mid-wall late gadolinium enhancement (LGE). Compared to the control group, patients with LVNC had higher end-diastolic volume (EDV) indexed for body surface area (BSA), lower ejection fraction (EF), and lower LV strain parameters (all p < 0.05). Children with LVNC also presented with thicker RV apical trabeculation, whereas there were no differences in RV EF and EDV/BSA between the groups. Nevertheless, children with LVNC had impaired RV GRS and GCS (both p < 0.05). Conclusions: LVNC in pediatric patients is associated with LV enlargement and impaired LV systolic function. Additionally, children with LVNC have increased RV trabeculations and subclinical impairment of RV myocardial deformation.

BackgroundCardiovascular magnetic resonance (CMR) imaging in patients with hypertrophic cardiomyopathy (HCM) enables the assessment of not only left ventricular (LV) hypertrophy and scarring but also the severity of mitral regurgitation. CMR assessment of mitral regurgitation is primarily based on the difference between LV stroke volume (LVSV) and aortic forward flow (Ao) measured using the phase-contrast (PC) technique. However, LV outflow tract (LVOT) obstruction causing turbulent, non-laminar flow in the ascending aorta may impact the accuracy of aortic flow quantification, leading to false conclusions regarding mitral regurgitation severity. Thus, we decided to quantify mitral regurgitation in patients with HCM using Ao or, alternatively, main pulmonary artery forward flow (MPA) for mitral regurgitation volume (MRvol) calculations.MethodsThe analysis included 143 prospectively recruited subjects with HCM and 15 controls. MRvol was calculated as the difference between LVSV computed with either the inclusion (LVSVincl) or exclusion (LVSVexcl) of papillary muscles and trabeculations from the blood pool and either Ao (MRvolAoi or MRvolAoe) or MPA (MRvolMPAi or MRvolMPAe). The presence or absence of LVOT obstruction was determined based on Doppler echocardiography findings.ResultsMRvolAoi was higher than MRvolMPAi in HCM patients with LVOT obstruction [47.0 ml, interquartile range (IQR) = 31.5–60.0 vs. 35.5 ml, IQR = 26.0–51.0; p < 0.0001] but not in non-obstructive HCM patients (23.0 ml, IQR = 16.0–32.0 vs. 24.0 ml, IQR = 15.3–32.0; p = 0.26) or controls (18.0 ml, IQR = 14.3–21.8 vs. 20.0 ml, IQR = 14.3–22.0; p = 0.89). In contrast to controls and HCM patients without LVOT obstruction, in HCM patients with LVOT obstruction, aortic flow-based MRvol (MRvolAoi) was higher than pulmonary-based findings (MRvolMPAi) (bias = 9.5 ml; limits of agreement: −11.7–30.7 with a difference of 47 ml in the extreme case). The differences between aortic-based and pulmonary-based MRvol values calculated using LVSVexcl mirrored those derived using LVSVincl. However, MRvol values calculated using LVSVexcl were lower in all the groups analyzed (HCM with LVOT obstruction, HCM without LVOT obstruction, and controls) and with all methods of MRvol quantification used (p ≤ 0.0001 for all comparisons).ConclusionsIn HCM patients, LVOT obstruction significantly affects the estimation of aortic flow, leading to its underestimation and, consequently, to higher MRvol values than those obtained with MPA-based MRvol calculations.Electronic supplementary materialThe online version of this article (doi:10.1186/s12968-017-0417-8) contains supplementary material, which is available to authorized users.

ObjectivesTo investigate biatrial mechanics and their relation with left ventricular outflow tract (LVOT) obstruction (LVOTO), the degree of hypertrophy, indices of ventricular diastolic function and fibrosis in children with hypertrophic cardiomyopathy (HCM).MethodsFifty-five consecutive, prospectively recruited children with HCM (mean age 12.5 ± 4.6 years, 69.1% male), 19 (34.5%) of whom had LVOTO, underwent cardiac magnetic resonance and echocardiography with quantification of phasic components of biatrial function, biventricular diastolic function and fibrosis. Twenty healthy, sex-matched subjects served as controls.ResultsWe found a significant increase of left atrial (LA) and right atrial (RA) volumes and reduction in the majority of indices of contractile function, strains and strain rates (p < 0.05) in children with HCM compared with controls. Nearly all of the LA dynamics markers attained a significant association with the LVOT gradient (p < 0.05), the RA volumes and contractile functions were affected by LV fibrosis and mass (p < 0.05), and the RA mechanical components were related to the degree of LVOTO (p < 0.05). The minority of biatrial dynamics markers were associated with indices of ventricular diastolic function.ConclusionsThe majority of biatrial volumetric and functional indices were severely compromised in children with HCM compared with controls. The degree of LVOTO appears to trigger LA volumetric and LA and RA mechanical malfunction. On the other hand, the deterioration of RA volumetric components was linked to LV fibrosis and mass.Key Points • Biatrial function was severely compromised in children with HCM. • Left atrial malfunction was associated with the degree of LVOTO. • Fibrosis and LV mass were related to RA volumetric and contractile dysfunction. • The degree of LVOTO was linked to right atrial mechanical abnormalities.

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