Injectable biomaterials are an attractive therapy to attenuate left ventricular (LV) remodeling after myocardial infarction (MI). Although studies have shown that injectable hydrogels improve cardiac structure and function in vivo, temporal changes in infarct material properties after treatment have not been assessed. Emerging imaging and modeling techniques now allow for serial, non-invasive estimation of infarct material properties. Specifically, cine MRI assesses global LV structure and function, late-gadolinium enhancement (LGE) MRI enables visualization of infarcted tissue to quantify infarct expansion, and spatial modulation of magnetization (SPAMM) tagging provides passive wall motion assessment as a measure of tissue strain, which can all be used to evaluate infarct properties when combined with finite element (FE) models. In this work, we investigated the temporal effects of degradable hyaluronic acid (HA) hydrogels on global LV remodeling, infarct thinning and expansion, and infarct stiffness in a porcine infarct model for 12 weeks post-MI using MRI and FE modeling. Hydrogel treatment led to decreased LV volumes, improved ejection fraction, and increased wall thickness when compared to controls. FE model simulations demonstrated that hydrogel therapy increased infarct stiffness for 12 weeks post-MI. Thus, evaluation of myocardial tissue properties through MRI and FE modeling provides insight into the influence of injectable hydrogel therapies on myocardial structure and function post-MI.

AIM:To compare 3D Black Blood turbo spin echo (TSE) sampling perfection with application-optimized contrast using different flip angle evolution (SPACE) vs 2D TSE in evaluating atherosclerotic plaques in multiple vascular territories. METHODS:The carotid, aortic, and femoral arterial walls of 16 patients at risk for cardiovascular or atherosclerotic disease were studied using both 3D black blood magnetic resonance imaging SPACE and conventional 2D multi-contrast TSE sequences using a consolidated imaging approach in the same imaging session. Qualitative and quantitative analyses were performed on the images. Agreement of morphometric measurements between the two imaging sequences was assessed using a two-sample t -test, calculation of the intra-class correlation coefficient and by the method of linear regression and Bland-Altman analyses. RESULTS:No statistically significant qualitative differences were found between the 3D SPACE and 2D TSE techniques for images of the carotids and aorta. For images of the femoral arteries, however, there were statistically significant differences in all four qualitative scores between the two techniques. Using the current approach, 3D SPACE is suboptimal for femoral imaging. However, this may be due to coils not being optimized for femoral imaging. Quantitatively, in our study, higher mean total vessel area measurements for the 3D SPACE technique across all three vascular beds were observed. No significant differences in lumen area for both the right and left carotids were observed between the two techniques. Overall, a significant-correlation existed between measures obtained between the two approaches. Core tip: The traditional approach to atherosclerotic plaque imaging using magnetic resonance (MR) is the two-dimensional (2D) multi-contrast turbo spin echo technique. However, 3D black blood MR imaging is becoming the preferred methodology for evaluating plaque burden non-invasively. Comparing imaging results obtained using both 3D sampling Perfection with application-optimized contrast using different flip angle evolution (SPACE) and conventional 2D multi-contrast TSE sequences in evaluating vascular territories showed good agreement in both qualitative and quantitative measurements between the two techniques. 3D SPACE technique is a promising and potentially feasible approach for the evaluation of multiple vascular beds in patients at risk for cardiovascular disease. CONCLUSION:Wong SK, Mobolaji-Iawal M, Arama L, Cambe J, Biso S, Alie N, Fayad ZA, Mani V. Atherosclerosis imaging using 3D black blood TSE SPACE vs 2D TSE.

Muscle weakness and enhanced fatigue are common complaints of cancer patients undergoing chemotherapy. In order to evaluate the underlying mechanisms, the present study assessed the acute effects of the chemotherapeutic drug, doxorubicin, on spontaneous motor activity and swimming performance of mice. Before and after i.p. injection of doxorubicin at 25 mg/kg into each mouse, the number of spontaneous movements was monitored for 24 hr using Columbus Instruments Opto‐varimax‐mini activity meter, and the integrated swimming activity (V.sec) was recorded for 40 min using a digital swimming monitor (Pagala, 1999).Doxorubicin, within the clinical dose range, significantly reduced the stereotypic, ambulatory, and thus the total number of spontaneous movements of the mice in a 24 hr period (Table 1). Doxorubicin also caused a significant reduction in the integrated swimming activity of the mice over a 40 min period (Table 1). These results indicate that chemotherapeutic agents may significantly decrease the motivation and endurance for physical activity.Supported by a special grant from Maimonides Med. Ctr.