Xiao Ming Zhang

Correlation between tumor perfusion and lipiodol deposition in hepatocellular carcinoma after transarterial chemoembolization.

PURPOSE To study the correlation of tumor perfusion with lipiodol deposition in hepatocellular carcinoma (HCC) after transarterial chemoembolization with multidetector computed tomography (MDCT) perfusion imaging. MATERIALS AND METHODS MDCT perfusion imaging was performed in 24 patients with HCC 1 to 7 days before chemoembolization. The computed tomography (CT) perfusion parameters, such as hepatic arterial perfusion (HAP), hepatic portal perfusion (HPP), total liver perfusion (TLP), and hepatic arterial perfusion index (HAPI), were calculated with the slope method. The follow-up CT scans (noncontrast) were performed 4 weeks after chemoembolization to analyze lipiodol deposition. The lipiodol deposition in the tumor was classified into three grades and compared with CT perfusion parameters before chemoembolization. RESULTS The HAP and TLP of tumors before chemoembolization were correlated with the grades of lipiodol deposition in tumors after chemoembolization (r = 0.768, P < .0001 and r = 0.616, P = .001, respectively). However, the HPP and HAPI of the tumors were not related to the grades of iodized oil deposition (r = 0.227, P = .286 and r = 0.111, P = .607, respectively). Higher HAP was correlated with better lipiodol deposition, and lower HAP was correlated with poorer lipiodol deposition. CONCLUSIONS MDCT perfusion imaging has the potential to help select more appropriate patients with HCC for chemoembolization.

MR imaging for the longevity of mesenchymal stem cells labeled with poly-L-lysine–Resovist complexes

Superparamagnetic iron oxide (SPIO) nanoparticles are emerging as ideal probes for noninvasive cell tracking. In this study, poly-L-lysine (PLL) was mixed with Resovist to form the PLL-Resovist complexes and the control of the complexes formed by PLL and Resovist and their subsequent properties was easily achievable. MSCs could be safely and efficiently labeled for MR imaging using PLL-Resovist complexes (w/w 0.01:1) and the labeled MSCs could be detected to have definite decreased signal intensity on T(2)-weight imaging until 20 days with standard 1.5 T MR equipment. This study describes a simple protocol to label MSCs using PLL-Resovist complexes and the results presented in our study can provide a basis for the application of PLL-Resovist complexes cell labeling.

The Celiac Ganglia: Anatomic Study Using MRI in Cadavers

OBJECTIVE Our objective was to facilitate the in vivo identification of the celiac ganglia on MRI by using MRI to identify the celiac ganglia in cadavers. CONCLUSION MRI can show the celiac ganglia accurately in cadavers when the ganglia are large and labeled with gadolinium. The findings in cadavers can be a reference for identifying the celiac ganglia in vivo.

Abdominal MRI at 3.0 T: LAVA-Flex compared with conventional fat suppression T1-weighted images.

To study liver imaging with volume acceleration‐flexible (LAVA‐Flex) for abdominal magnetic resonance imaging (MRI) at 3.0 T and compare the image quality of abdominal organs between LAVA‐Flex and fast spoiled gradient‐recalled (FSPGR) T1‐weighted imaging.

Magnetic resonance imaging versus Acute Physiology And Chronic Healthy Evaluation II score in predicting the severity of acute pancreatitis.

OBJECTIVE To study the correlation between established magnetic resonance (MR) imaging criteria of disease severity in acute pancreatitis and the Acute Physiology And Chronic Healthy Evaluation II (APACHE II) score, and to assess the utility of each prognostic indicators in acute pancreatitis. MATERIALS AND METHODS In this study there were 94 patients with acute pancreatitis (AP), all had abdominal MR imaging. MR findings were categorized into edematous and necrotizing AP and graded according to the MR severity index (MRSI). The APACHE II score was calculated within 24h of admission, and local complications, death, duration of hospitalization and ICU were recorded. Statistical analysis was performed to determine their correlation. RESULTS In patients with pancreatitis, no significant correlation can be found between the APACHE II score and the MRSI score (P=0.196). The MRSI score correlated well with morbidity (P=0.006) but not with mortality (P=0.137). The APACHE II score correlated well with mortality (P=0.002) but not with the morbidity (P=0.112). The MRSI score was superior to the APACHE II score as a predictor of the length of hospitalization (r=0.52 vs. r=0.35). A high MRSI and APACHE II score correlated with the need for being in the intensive care unit (ICU) (P=0.000 and P=0.000, respectively). CONCLUSION In patients with pancreatitis, MRSI is superior to APACHE II in assessing local complications from pancreatitis but has a limited role in determining systemic complications in which the APACHE II score excels.

Functional Magnetic Resonance Imaging in Acute Kidney Injury: Present Status

Acute kidney injury (AKI) is a common complication of hospitalization that is characterized by a sudden loss of renal excretory function and associated with the subsequent development of chronic kidney disease, poor prognosis, and increased mortality. Although the pathophysiology of renal functional impairment in the setting of AKI remains poorly understood, previous studies have identified changes in renal hemodynamics, perfusion, and oxygenation as key factors in the development and progression of AKI. The early assessment of these changes remains a challenge. Many established approaches are not applicable to humans because of their invasiveness. Functional renal magnetic resonance (MR) imaging offers an alternative assessment tool that could be used to evaluate renal morphology and function noninvasively and simultaneously. Thus, the purpose of this review is to illustrate the principle, application, and role of the techniques of functional renal MR imaging, including blood oxygen level-dependent imaging, arterial spin labeling, and diffusion-weighted MR imaging, in the management of AKI. The use of gadolinium in MR imaging may exacerbate renal impairment and cause nephrogenic systemic fibrosis. Therefore, dynamic contrast-enhanced MR imaging will not be discussed in this paper.

Liver dynamic contrast-enhanced MRI for staging liver fibrosis in a piglet model.

To determine whether dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) could monitor progression of liver fibrosis in a piglet model, and which DCE‐MRI parameter is most accurate for staging this disease.

MR imaging for blunt pancreatic injury

OBJECTIVE To study the MR imaging features of blunt pancreatic injury. MATERIALS AND METHODS Nine patients with pancreatic injury related to blunt abdominal trauma confirmed by surgery performed MR imaging. Two abdominal radiologists conducted a review of the MR images to assess pancreatic parenchymal and pancreatic duct injury, and associated complications. RESULT Diagnostic quality MR images were obtained in each of the nine patients. In the nine patients, pancreatic fracture, laceration and contusion were depicted on MR imaging in five, one and three patients, respectively. There were six patients with pancreatic duct disruption, eight patients with peripancreatic fluid collections, and four patients with peripancreatic pseudocyst or hematoma, respectively. All of the MR imaging findings was corresponded to surgical findings. CONCLUSION MR imaging is an effective method to detect blunt pancreatic injury and may provide information to guide management decisions.

GRE T2-Weighted MRI: Principles and Clinical Applications

The sequence of a multiecho gradient recalled echo (GRE) T2*-weighted imaging (T2*WI) is a relatively new magnetic resonance imaging (MRI) technique. In contrast to T2 relaxation, which acquires a spin echo signal, T2* relaxation acquires a gradient echo signal. The sequence of a GRE T2*WI requires high uniformity of the magnetic field. GRE T2*WI can detect the smallest changes in uniformity in the magnetic field and can improve the rate of small lesion detection. In addition, the T2* value can indirectly reflect changes in tissue biochemical components. Moreover, it can be used for the early diagnosis and quantitative diagnosis of some diseases. This paper reviews the principles and clinical applications as well as the advantages and disadvantages of GRE T2*WI.

The Effect of Superparamagnetic Iron Oxide with iRGD Peptide on the Labeling of Pancreatic Cancer Cells In Vitro: A Preliminary Study

The iRGD peptide loaded with iron oxide nanoparticles for tumor targeting and tissue penetration was developed for targeted tumor therapy and ultrasensitive MR imaging. Binding of iRGD, a tumor homing peptide, is mediated by integrins, which are widely expressed on the surface of cells. Several types of small molecular drugs and nanoparticles can be transfected into cells with the help of iRGD peptide. Thus, we postulate that SPIO nanoparticles, which have good biocompatibility, can also be transfected into cells using iRGD. Despite the many kinds of cell labeling studies that have been performed with SPIO nanoparticles and RGD peptide or its analogues, only a few have applied SPIO nanoparticles with iRGD peptide in pancreatic cancer cells. This paper reports our preliminary findings regarding the effect of iRGD peptide (CRGDK/RGPD/EC) combined with SPIO on the labeling of pancreatic cancer cells. The results suggest that SPIO with iRGD peptide can enhance the positive labeling rate of cells and the uptake of SPIO. Optimal functionalization was achieved with the appropriate concentration or concentration range of SPIO and iRGD peptide. This study describes a simple and economical protocol to label panc-1 cells using SPIO in combination with iRGD peptide and may provide a useful method to improve the sensitivity of pancreatic cancer imaging.