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The purpose of this study was to validate a first‐pass MRI method for imaging myocardial perfusion with multislice coverage and relatively small analyzable regions of interest (ROIs). A fast gradient‐echo (FGRE) sequence with an echo‐train (ET) readout was used to achieve multislice coverage, and a high dose of a contrast agent (CA) was used to achieve a high signal‐to‐noise ratio (SNR). Dogs (N= 6) were studied 1 day after reperfused myocardial infarction, and fluorescent microspheres were used as a standard for perfusion. First‐pass MRI correlated well vs. microsphere flow, achieving mean R values of 0.87 (range = 0.82–0.93), 0.71 (range = 0.46–0.85), and 0.72 (range = 0.49–0.95) for subendocardial ROIs, transmural ROIs, and the endocardial‐epicardial ratio, respectively. Additionally, analysis of myocardial time‐intensity curves (TICs) indicated that 15.8 ± 6.6° sectors, corresponding to 260 μl of endocardium, can be analyzed (R2> 0.95). Magn Reson Med 47:482–491, 2002. Published 2002 Wiley‐Liss, Inc.

Background:Rifampicin has been employed in various endocarditis antibiotic regimens, particularly in prosthetic, staphylococcus aureus(SA) and culture-negative cases. However, this practice is not without controversy.Purpose:To perform a meta-analysis aimed at ascertaining the efficacy and safety of adjunctive rifampicin use in endocarditis.Methods:We systematically searched MEDLINE, Embase, Web of Science, Cochrane Library and Google Scholar, from inception to June 1st, 2021, for studies comparing rifampicin-containing antibiotic regimens with those comprising no rifamycin derivatives, in the setting of endocarditis. The primary endpoint was all-cause death, while relapse, bail-out valvular surgery, microbiological failure (lasting positivity of blood cultures) and hepatotoxicity (fivefold or higher increase in transaminase levels) were secondary outcomes. SA infections were investigated separately, with respect to the primary endpoint. Mantel-Haenszel odds ratios (ORs) were pooled using traditional meta-analytic techniques, under a random-effects model.Results:2 randomized, 1 non-randomized prospective and 6 retrospective studies, featuring 886 patients (of whom 322 allocated to rifampicin), were included. While 8 studies addressed staphylococcal endocarditis (with 3 of them dealing exclusively with SA infections), prosthetic and culture-negative cases were only focused on 1 study each. There were 96 deaths (from 7 studies), 32 relapses (from 6 studies), 35 bail-out valvular surgeries (from 4 studies), 14 microbiological failures (from 2 studies) and 32 hepatotoxicity cases (from 5 studies). Rifampicin use was associated with a tendency towards higher all-cause mortality (OR 1.63, 95% CI 0.85-3.12, P 0.14, i212%), which held true for SA infections (OR 1.63, 95% CI 0.67-3.92, P 0.28, i220%), and bail-out valve surgery (OR 2.03, 95% CI 0.65-6.34, P 0.22, i25%). Relapse and microbiological failures rates were similar between groups (OR 1.25, 95% CI 0.59-2.65, P 0.56, i20% and OR 1.3, 95% CI 0.24-6.90, P 0.76, i241%, respectively). Hepatotoxicity odds were greater in the rifampicin arm (OR 3.24, 95% CI 1.35-7.77, P 0.008, i20%).Conclusion:Currently available evidence does not support rifampicin use in endocarditis.