Background— Positron-emission tomography (PET) tracers for myocardial perfusion are commonly labeled with short-lived isotopes that limit their widespread clinical use. 18 F-BMS-747158-02 ( 18 F-BMS) is a novel pyridaben derivative that was evaluated for assessment of myocardial perfusion by comparison with 13 N-ammonia ( 13 NH 3 ) and with radioactive microspheres in a pig model. Methods and Results— Fourteen pigs injected with 500 MBq of 13 NH 3 or 100 to 200 MBq of 18 F-BMS underwent dynamic PET at rest and during pharmacological stress. In 8 of these pigs, 18 F-BMS was injected during stress combined with transient, 2.5-minute constriction of the left anterior descending coronary artery. Radioactive microspheres were coinjected with 18 F-BMS. Ratios of myocardial tracer uptake to surrounding tissues were determined, and myocardial blood flow was quantified by compartmental modeling. Both tracers showed high and homogeneous myocardial uptake. Compared with 13 NH 3 , 18 F-BMS showed higher activity ratios between myocardium and blood (rest 2.5 versus 4.1; stress 2.1 versus 5.8), liver (rest 1.2 versus 1.8; stress 0.7 versus 2.0), and lungs (rest 2.5 versus 4.2; stress 2.9 versus 6.4). Regional myocardial blood flow assessed with 18 F-BMS PET showed good correlation ( r =0.88, slope=0.84) and agreement (mean difference −0.10 [25th percentile −0.3, 75th percentile 0.1 mL · min −1 · g −1 ]) with that measured with radioactive microspheres over a flow range from 0.1 to 3.0 mL · min −1 · g −1 . The extent of defects induced by left anterior descending coronary artery constriction measured by 18 F-BMS and microspheres also correlated closely ( r =0.63, slope=1.1). Conclusions— 18 F-BMS-747158-02 is a very attractive new PET perfusion tracer that allows quantitative assessment of regional myocardial perfusion over a wide flow range. The long half-life of 18 F renders this tracer useful for clinical PET/CT applications in the workup of patients with suspected or proven coronary artery disease.

Background-The extracellular matrix (ECM) plays an important role in the pathogenesis of atherosclerosis and in-stent restenosis. Elastin is an essential component of the ECM. ECM degradation can lead to plaque destabilization, whereas enhanced synthesis typically leads to vessel wall remodeling resulting in arterial stenosis or in-stent restenosis after stent implantation. The objective of this study was to demonstrate the feasibility of MRI of vascular remodeling using a novel elastin-binding contrast agent (BMS-753951). Methods and Results-Coronary injury was induced in 6 pigs by endothelial denudation and stent placement. At day 28, delayed-enhancement MRI coronary vessel wall imaging was performed before and after injection of gadoliniumdiethylene triamine pentaacetic acid (Gd-DTPA). Two days later, DE-MRI was repeated after administration of BMS-753951. Contrast-to-noise-ratio and areas of enhancement were determined. Delayed-enhancement MRI with BMS-753951 caused strong enhancement of the aortic, pulmonary artery, and injured coronary artery walls, whereas Gd-DTPA did not. Delayed-enhancement MRI of the stented coronary artery with BMS-753951 yielded a 3-fold higher contrast-to-noise-ratio when compared with the balloon-injured and control coronary artery (21Ϯ6 versus 7Ϯ3 versus 6Ϯ4; PϽ0.001). The area of enhancement correlated well with the area of remodeling obtained from histological data (R

Ischemia/reperfusion (I/R) injury is a main cause of primary dysfunction or non-function after liver transplantation (LTx). Recent evidence indicates that an increase in nitric oxide (NO) production after LTx is associated with I/R injury. The aim of this study was to demonstrate that low-dose FK506 in combination with aminoguanidine (AGH), which leads to a reduction of NO levels, has a protective effect by reducing I/R associated injury after LTx. Fortyone DA-(RT1av1) rats served as donors and recipients for syngenic orthotopic arterialised LTx. They were divided into 4 groups: controls without pre-/treatment (I), pre-/treatment with high-dose FK506 (II), pre-/treatment with AGH only (III), and pre-/treatment with low-dose FK506 in combination with AGH (IV). After LTx the laboratory parameters and liver biopsy were performed. The levels of transaminase (ALT) in groups I, II and III were significantly higher on day 3 after LTx compared to group IV (p = 0.001, p = 0.001, p = 0.000). In group IV the I/R-associated liver necrosis rate was reduced significantly. Our results demonstrated that a combined dual pharmacological pretreatment (group IV) reduced I/R injury of the graft after LTx in a rat model.