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In the progression of ischemia, pH is important and is essential in elucidating the association between metabolic disruption, lactate formation, acidosis and tissue damage. Chemical exchange-dependent saturation transfer (CEST) imaging can be used to detect tissue pH and, in particular, a specific form of CEST magnetic resonance imaging (MRI), termed amide proton transfer (APT) MRI, which is sensitive to pH and can detect ischemic lesions, even prior to diffusion abnormalities. The critical parameter governing the ability of CEST to detect pH is the sequence. In the present study, a novel strategy was used, based on the gradient echo sequence (GRE), which involved the insertion of a magnetization transfer pulse in each repetition time (TR) and minimizing the TR for in vivo APT imaging. The proposed GRE-APT MRI method was initially verified using a tissue-like pH phantom and optimized MRI parameters for APT imaging. In order to assess the range of acute cerebral infarction, rats (n=4) were subjected to middle cerebral artery occlusion (MCAO) and MRI scanning at 7 telsa (T). Hyperacute ischemic tissue damage was characterized using multiparametric imaging techniques, including diffusion, APT and T2-Weighted MRI. By using a magnetization transfer pulse and minimizing TR, GRE-APT provided high spatial resolution and a homogeneous signal, with clearly distinguished cerebral anatomy. The GRE-APT and diffusion MRI were significantly correlated with lactate content and the area of cerebral infarction in the APT and apparent diffusion coefficient (ADC) maps matched consistently during the hyperacute period. In addition, compared with the infarction area observed on the ADC MRI map, the APT map contained tissue, which had not yet been irreversibly damaged. Therefore, GRE-APT MRI waa able to detect ischemic lactic acidosis with sensitivity and spatiotemporal resolution, suggesting the potential use of pH MRI as a surrogate imaging marker of impaired tissue metabolism for the diagnosis and prognosis of hyperacute stroke.

Progress in the development of stem cell and gene therapy requires repeatable and non-invasive techniques to monitor the survival and integration of stem cells in vivo with a high temporal and spatial resolution. The purpose of the present study was to examine the feasibility of using the standard contrast agent gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) to label rat mesenchymal stem cells (MSCs) for stem cell tracking. MSCs, obtained from the bilateral femora of rats, were cultured and propagated. The non-liposomal lipid transfection reagent effectene was then used to induce the intracellular uptake of Gd-DTPA. Electron microscopy was used to detect the distribution of Gd-DTPA particles in the MSCs. The labeling efficiency of the Gd-DTPA particles in the MSCs was determined using spectrophotometry, and MTT and trypan blue exclusion assays were used to evaluate the viability and proliferation of the labeled MSCs. T1-weighted magnetic resonance imaging (MRI) was used to observe the labeled cells in vitro and in the rat brain. Gd-DTPA particles were detected inside the MSCs using transmission electron microscopy and a high labeling efficiency was observed. No difference was observed in cell viability or proliferation between the labeled and unlabeled MSCs (P>0.05). In the in vitro T1-weighted MRI and in the rat brain, a high signal intensity was observed in the labeled MSCs. The T1-weighted imaging of the labeled cells revealed a significantly higher signal intensity compared with that of the unlabeled cells (P

Characterization of endothelial shear stress (ESS) may allow for prediction of the progression of atherosclerosis. The aim of this investigation was to develop a non-invasive approach for in vivo assessment of ESS by coronary computed tomography angiography (CTA) and to compare it with ESS derived from invasive coronary angiography (ICA). A total of 41 patients with mild or intermediate coronary stenoses who underwent both CTA and ICA were included in the analysis. Two geometrical models of the interrogated vessels were reconstructed separately from CTA and ICA images. Subsequently, computational fluid dynamics were applied to calculate the ESS, from which ESSCTA and ESSICA were derived, respectively. Comparisons between ESSCTA and ESSICA were performed on 163 segments of 57 vessels in the CTA and ICA models. ESSCTA and ESSICA were similar: mean ESS: 4.97 (4.37–5.57) Pascal versus 4.86 (4.27–5.44) Pascal, p = 0.58; minimal ESS: 0.86 (0.67–1.05) Pascal versus 0.79 (0.63–0.95) Pascal, p = 0.37; and maximal ESS: 14.50 (12.62–16.38) Pascal versus 13.76 (11.44–16.08) Pascal, p = 0.44. Good correlations between the ESSCTA and the ESSICA were observed for the mean (r = 0.75, p

Pedunculated hepatocellular carcinoma (P-HCC) is a rare type of HCC, defined as a carcinoma protruding from the liver with or without a pedicle with a low degree of liver invasion. The present study aimed to evaluate the characteristics of blood supply of P-HCC prior to and following transcatheter arterial chemoembolization (TACE) treatment. Angiographic findings prior to and following TACE treatment in 39 patients with P-HCC were analyzed retrospectively. Angiography performed at the first TACE session revealed 70 tumor-feeding arteries collectively in all patients, including 31/70 (44.0%) extrahepatic parasitic arteries in 23/39 patients (59.0%). The intrahepatic arteries served as the main blood supply to P-HCC in all patients. Extrahepatic collateral blood supplies to P-HCCs were significantly associated with larger tumor diameter (χ2=164.000, P

Background/aims Surgical resection is the current treatment for focal nodular hyperplasia of the liver (FNH) when indicated. However, tumor location and size, patient comorbidities, and risk of complications may limit surgical options in some cases. Our goal was to evaluate the therapeutic effect of transarterial embolization (TAE) using pingyangmycin lipiodol emulsion (PLE) and polyvinyl alcohol particles to treat FNH. Methodology Four patients with FNH, who experienced dull pain in the upper abdomen or liver area and confirmed by biopsy, were treated by TAE with PLE and polyvinyl alcohol (diameter: 500µm-700µm). Therapeutic effects including changes in lesion diameter and symptomatic improvement, and occurrence of complications, were evaluated for a follow-up period ranging from 12 to 42 months after the procedure. Results All of four patients were successfully treated with PLE and polyvinyl alcohol embolization. One month after the procedure, dull pain in the upper abdomen or liver area vanished completely. Follow-up examination by CT or MRI revealed complete resolution in two cases and an obvious decrease in the other two cases. No immediate or delayed postembolization complications were encountered. Conclusion Transarterial embolization using PLE and polyvinyl alcohol should be considered as a safe and effective method for the treatment of FNH.

A 74-year-old man presented with a progressively worsening pain in sacrum and was diagnosed to have a sacral chordoma by biopsy in May, 2004. Percutaneous intratumoral injection with lipiodol-pingyangmycin suspension (LPS) was carried out under image guidance and repeated when the pain in sacrum recurred and the tumor increased. During a 6-year follow-up period, three sessions of this treatment were executed. CT imaging and Karnofsky Performance Score were used to evaluate the size of tumor and quality of life, respectively. The patient was free of pain after each procedure and had a high quality of life with a Karnofsky Performance Score above 80 points. The tumor lesion in sacral area was effectively controlled. No complications were observed. Percutaneous intratumoral injection with LPS under image guidance may be an effective and safe alternative for the patients with sacral chordoma.