Evaluation of sampling density on the accuracy of aortic pulse wave velocity from velocity‐encoded MRI in patients with Marfan syndrome

Purpose:

To evaluate the effect of spatial (ie, number of sampling locations along the aorta) and temporal sampling density on aortic pulse wave velocity (PWV) assessment from velocity‐encoded MRI in patients with Marfan syndrome (MFS).

Materials and Methods:

Twenty‐three MFS patients (12 men, mean age 36 ± 14 years) were included. Three PWV‐methods were evaluated: 1) reference PWV_i.p. from in‐plane velocity‐encoded MRI with dense temporal and spatial sampling; 2) conventional PWV_t.p. from through‐plane velocity‐encoded MRI with dense temporal but sparse spatial sampling at three aortic locations; 3) EPI‐accelerated PWV_t.p. with sparse temporal but improved spatial sampling at five aortic locations with acceleration by echo‐planar imaging (EPI).

Results:

Despite inferior temporal resolution, EPI‐accelerated PWV_t.p. showed stronger correlation (r = 0.92 vs. r = 0.65, P = 0.03) with reference PWV_i.p. in the total aorta, with less error (8% vs. 16%) and variation (11% vs. 27%) as compared to conventional PWV_t.p.. In the aortic arch, correlation was comparable for both EPI‐accelerated and conventional PWV_t.p. with reference PWV_i.p. (r = 0.66 vs. r = 0.67, P = 0.46), albeit 92% scan‐time reduction by EPI‐acceleration.

Conclusion:

Improving spatial sampling density by adding two acquisition planes along the aorta results in more accurate PWV assessment, even when temporal resolution decreases. For regional PWV assessment in the aortic arch, EPI‐accelerated and conventional PWV assessment are comparably accurate. Scan‐time reduction makes EPI‐accelerated PWV assessment the preferred method of choice. J. Magn. Reson. Imaging 2012; 36:1470–1476. © 2012 Wiley Periodicals, Inc.     

Noninvasive imaging in cardiac resynchronization therapy--part 1: selection of patients

Cardiac resynchronization therapy (CRT) is an established therapy for patients with advanced heart failure, depressed left ventricular function, and wide QRS complex. However, individual response varies, and a substantial amount of patients do not respond to CRT. Recent studies observed that assessment of inter- and particularly intraventricular dyssynchrony may allow identification of potential responders to CRT. In addition, presence of scar tissue and venous anatomy may play a role in the selection of candidates. In this review, an extensive overview of the available dyssynchrony measurements is provided using echocardiography as well as magnetic resonance imaging (MRI) and nuclear imaging. Furthermore, other information derived from MRI, nuclear imaging, and computed tomography useful for the selection of potential candidates for CRT will be discussed.     

Artemisinins,New Miconazole Potentiators Resulting in Increased Activity against Candida albicans Biofilms

Mucosal biofilm-related fungal infections are very common, and the incidence of recurrent oral and vulvovaginal candidiasis is significant. As resistance to azoles (the preferred treatment) is occurring, we aimed at identifying compounds that increase the activity of miconazole against Candida albicans biofilms. We screened 1,600 compounds of a drug-repositioning library in combination with a subinhibitory concentration of miconazole. Synergy between the best identified potentiators and miconazole was characterized by checkerboard analyses and fractional inhibitory concentration indices. Hexachlorophene, pyrvinium pamoate, and artesunate act synergistically with miconazole in affecting C. albicans biofilms. Synergy was most pronounced for artesunate and structural homologues thereof. No synergistic effect could be observed between artesunate and fluconazole, caspofungin, or amphotericin B. Our data reveal enhancement of the antibiofilm activity of miconazole by artesunate, pointing to potential combination therapy consisting of miconazole and artesunate to treat C. albicans biofilm-related infections.