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Background: In the previous studies, hemorrhage occurred only with the largest infarctions and studies confirmed a moderate correlation between the extent of necrosis and hemorrhage, but the extent of infarction size of these studies was limited. This study was to find the correlations between intramyocardial hemorrhage (IMH), myocardial infarction (MI), and myocardial edema (ME) from days 2 to 7 in a 7.0T MR scanner.Methods: The different degrees of myocardial ischemia were induced by occluding different sections of the proximal left anterior descending coronary artery (1–3 mm under the left auricle). T2*-mapping, T2-mapping and late gadolinium enhancement (LGE) sequences were performed on a 7.0T MR system at day 2 and 7. T2*- and T2-maps were calculated using a custom-made software. All areas were expressed as a percentage of the whole myocardial tissue of the left ventricle. The rats were divided into two groups based on the T2* results; MI with IMH was referred to as the +IMH group, while MI without IMH was referred to as the –IMH group.Results: The final experimental sample consisted of 25 rats in the +IMH group and 10 rats in the –IMH group. For the +IMH group. On day 2, There was a significant positive correlation between IMH size and MI size (r = 0.677, P

BackgroundLate gadolinium enhancement (LGE) is a standard method to evaluate myocardial fibrosis, but restricted due to contrast agent contraindications. Non-contrast T1rho can generate endogenous contrast, and detect fibrosis in chronic myocardial infarction. However, T1rho for hypertrophic cardiomyopathy (HCM) patients is still unreported. The present study aimed to investigate T1rho for fibrotic assessment and the clinical implication in HCM patients.Methods18 HCM patients and 8 controls underwent T1rho, cine, and LGE cardiac magnetic resonance (CMR). T1rho relaxation time maps were created. Left ventricular (LV) parameters assessed included wall thickness, wall thickening, chamber volumes, ejection function, and fibrotic size. New York Heart Association (NYHA) functional classification was conducted.ResultsHyper-T1rho value was identified in 12 HCM patients, consistent with LGE. The mean T1rho values of controls, LGE-negative patients, and remote myocardium of LGE-positive patients were 42.2±1.6ms, 43.9±2.5ms, and 42.5±1.2ms respectively, and these values showed no significant difference (all p>0.05). T1rho-3-SD and T1rho-4-SD fibrotic sizes (32.5±14.0% and 25.1±11.5%) did not differ from LGE fibrotic size (28.1±11.2%) (both p>0.05). For the fibrotic size, T1rho-3-SD method obtained the strongest correlation with LGE (r=0.88, p

Background The common T2 mapping is not suitable for the use in rat heart with high heart rate, unless data are acquired in multiple cardiac cycles. Purpose To evaluate a simplified T2 mapping method for faster assessment of myocardial edema and area at risk in a rat model of myocardial infarction. Material and Methods The simplified T2 mapping method (TR/TE, 1500 ms/10, 20, 30 ms) was implemented at a 7.0T MRI system. The accuracy of T2 mapping was compared with a standard T2 mapping method (TR, 2500 ms, 16 TEs equally spaced from 11 ms to 176 ms) in thigh muscles in rats ( n = 6) and a phantom. This method was further evaluated in normal rats ( n = 8) and rats with myocardial infarction ( n = 8). Late gadolinium enhancement images were also acquired in the rats with myocardial infarction. Results T2 values of simplified T2 mapping in the muscles and phantom were 27.3 ± 2 ms and 26.5 ± 1.1 ms, which were similar to the T2 values obtained by the standard T2 mapping method (28.1 ± 1.4 ms, P > 0.05; 26.9 ± 1.7 ms). No significant difference in T2 distribution (different segments and slices from base to apex) in the whole heart was found in normal rats (25.6 ± 3.3 ms, P > 0.05). The mean T2 value in the myocardial edema regions of myocardial infarction rats (37 ± 4.9 ms) was significantly higher than that of the normal rats (25.6 ± 3.3 ms, P Conclusion The simplified myocardial T2 mapping is technically feasible and accurate, and can readily detect myocardial edema and area at risk in rats with high heart rate.

Yushu Chen,1 Li Gong,2 Ning Gao,3 Jichun Liao,1 Jiayu Sun,1 Yuqing Wang,1 Lei Wang,1 Pengjin Zhu,1 Qing Fan,1 Yongqiang Andrew Wang,4 Wen Zeng,2 Hui Mao,3 Lily Yang,5 Fabao Gao11Molecular Imaging Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, 2Sichuan Primed Bio-Tech Group Co, Ltd, Chengdu, People’s Republic of China; 3Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, 4Ocean NanoTech, LLC, San Diego, CA, 5Department of Surgery, Emory University School of Medicine, Atlanta, GA, USAPurpose: To translate a recombinant peptide containing the amino-terminal fragment (ATF) of urokinase plasminogen activator receptor-targeted magnetic iron oxide (IO) nanoparticles (uPAR-targeted human ATF-IONPs) into clinical applications, we conducted a pilot study to evaluate the toxicity and pharmacokinetics of this nanoparticle in normal rhesus monkeys.Methods: We assessed the changes in the following: magnetic resonance imaging (MRI) signals from pretreatment stage to 14days posttreatment, serum iron concentrations from 5minutes posttreatment to 12 weeks posttreatment, routine blood examination and serum chemistry analysis results from pretreatment stage to 12weeks after administration, and results of staining of the liver with Perls’ Prussian Blue and hematoxylin–eosin at 24hours and 3months posttreatment in two rhesus monkeys following an intravenous administration of the targeted nanoparticles either with a polyethylene glycol (ATF-PEG-IONP) or without a PEG (ATF-IONP) coating.Results: The levels of alkaline phosphatase, alanine transaminase, and direct bilirubin in the two monkeys increased immediately after the administration of the IONPs but returned to normal within 20days and stayed within the normal reference range 3months after the injection. The creatinine levels of the two monkeys stayed within the normal range during the study. In addition, red blood cells, white blood cells, hemoglobin level, and platelets remained normal during the 3months of the study.Conclusion: All of the results suggest that a transient injury in terms of normal organ functions, but no microscopic necrotic lesions, was observed at a systemic delivery dose of 5mg/kg of iron equivalent concentration in the acute phase, and that no chronic toxicity was found 3months after the injection. Therefore, we conclude that uPAR-targeted IONPs have the potential to be used as receptor-targeted MRI contrasts as well as theranostic agents for the detection and treatment of human cancers in future studies. Keywords: uPAR-IONP, nonhuman primates, transient harm, self-healing

Background Atherosclerosis is one of the main risk factors cause acute cerebral-cardio vascular diseases. It's of great significance to establish an atherosclerosis animal model that can mimic the characteristics and nature course of human patients. Therefore, a rhesus monkey model was induced by high-fat diet to monitor their lipid profile and intima-media thickness (IMT) of artery walls and study atherosclerosis progression. Methods Fifty male rhesus monkeys were enrolled in this study. All of these monkeys were aged 7 to 14 years with BMI >30 kg/m2. They were fed with high-fat diet containing 10% of fat for the first 48 weeks. Use ultrasound to measure the IMT at bilateral common carotid arteries and their bifurcations and aorta (AO) of the monkeys, and screen out the individuals with thickened IMT for the next phase. In the next 48 weeks, some of these monkeys (n = 4) were fed with standard diet containing 3% fat. Meanwhile the other monkeys (n = 5) were fed with high-fat diet for another 48 weeks. Their serum lipid level was monitored and arterial IMT was also determined periodically. Results Serum lipid level of all 50 monkeys elevated after fed with high-fat diet for the first 48 weeks. IMT thickening at right common carotid bifurcation and aorta (AO) was thickened in 9 monkeys. Furthermore, 4 of these 9 monkeys were fed with standard diet and other 5 monkeys were fed with high-fat diet in the following 48 weeks. The serum lipid level of the 4 monkeys recovered and their IMT at RBIF and AO did not progress. However, the lipid level of other 5 monkeys remained high, and their IMT thickening of AO progressed, and plaques and calcification focuses were found at the anterior wall of aorta near the bifurcation of common iliac artery. Conclusions After high-fat diet induction for 96 weeks, serum lipid levels of rhesus monkeys elevated significantly, which subsequently caused IMT thickening and plaques formation. When IMT thickening occurred, further vascular injury may be prevented by reducing diet fat content. Our study indicates that vascular injury of high-fat diet induced rhesus monkey is similar to that of human in position and progression.

The goal of this study was to determine the effects of early reperfusion on the sizes of salvaged myocardium using cardiac magnetic resonance (CMR) imaging on a 7.0-T system (BioSpec 70/30, Bruker, Karlsruhe, Germany) in acute myocardial infarction in rats. Two groups (nonreperfusion n = 15

Gliomas are the most common type of intracranial tumor and have the highest rate of mortality. The aims of this study were to investigate the long-term course and biological behavior of orthotopically implanted C6 gliomas and to dynamically monitor the distribution of superparamagnetic iron oxide (SPIO) nanocomposite-labeled C6 glioma cells in rats using 7.0T MRI. We observed that in the MRI of the rats implanted with SPIO-labeled cells, there were pronounced hypointense signal bands, which faded over time, but remained visible up to day 27 after implantation. We observed that the first tumors were detected as early as 2 days after implantation, presenting as slightly hyperintense regions with indefinite boundaries in the T1-weighted images (T1WIs). On the 9th day, thick tumor feeder vessels, ~0.2 mm in diameter, were observed and these increased rapidly over time. Edema was observed in the labeled and unlabeled groups in the T2WIs. Both the central hypointense signal area and the peripheral cogwheel-shaped hypointense signal band in the tumor were observed on the post-contrast T1WIs, in accordance with the necrosis observed in the photomicrographs following hematoxylin and eosin (HE) staining. In conclusion, labeling tumor cells with SPIO and performing an MRI scan dynamically monitors the development and biological behavior of glioma at a very early stage.

To enrich our understanding of the mechanism of tumor lymphatic metastasis, we developed a model system for tracking metastatic tumor cells in the lymphatic system with cellular magnetic resonance imaging (MRI) in live mice to observe the interaction between tumor cells and the lymphatic system. Nude mice were inoculated subcutaneously with superparamagnetic iron oxide (SPIO)-labeled and unlabeled LOVO cells in the foot pad, groin, or axillary area. Serial 7 T MRI of the tumors and surrounding regions was performed in the following 2 weeks. After imaging, tumor tissues and regional lymph nodes were collected and subjected to immunohistologic analysis. T 2 /T 2 *-weighted MRIs showed the primary tumor growth and the draining lymphatic architecture, as well as the SPIO-labeled tumor cells metastasized into the regional lymph node at 8 days. MRIs also revealed information on sentinel lymph node mapping with high-resolution anatomic information. Histologic findings confirmed the in vivo MRI results and revealed lymphangiogenesis, angiogenesis, infiltration of macrophages, and expression of vascular endothelial growth factor C in tumor and draining lymph nodes as well. This technology provides a powerful tool for tracking SPIO-labeled cancer cells in the lymphatics by cellular MRI. There was a close relationship between tumor lymphatic metastasis and lymphangiogenesis.

Joint Bone Spine - In Press.Proof corrected by the author Available online since samedi 21 septembre 2013

Background Hypertrophic cardiomyopathy (HCM) is a genetic disease characterized by heterogeneous clinical symptoms and able to be visualized by cardiac magnetic resonance (CMR). Late gadolinium enhancement (LGE) represents myocardial fibrosis. There is still a challenge for HCM patients with contrast agent contraindication. T1rho CMR has been reported to determine fibrosis in myocardial infarction. To our best knowledge, no T1rho studies in HCM patients reported. We aimed to explore whether T1rho CMR detects fibrosis in HCM patients.