Solid Pancreatic Lesions: Characterization by Using Timing Bolus Dynamic Contrast-enhanced MR Imaging Assessment-A Preliminary Study
ABSTRACT Purpose:To assess the feasibility of post-processing dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging timing bolus data by using a three-dimensional radial gradient-echo technique with k-space-weighted image contrast (KWIC) for the characterization of solid pancreatic diseases.Materials and Methods:This retrospective study was approved by the institutional review board, and informed consent was waived. A total of 45 patients suspected of having biliary or pancreatic disease underwent pancreatic MR examination with a 3.0-T imager with a low-dose (2 mL gadopentetate dimeglumine) timing bolus by using the radial KWIC technique. There were 24 patients with pancreatic cancers, eight with pancreatic neuroendocrine tumors (PNETs), three with chronic pancreatitis, and 10 with a normal pancreas. By using a dedicated postprocessing software program for DCE MR imaging, the following perfusion parameters were measured for tumor and nontumorous parenchyma: volume transfer coefficient (K(trans)) and extracellular extravascular volume fraction; the rate constant (k(ep)) and initial area under the concentration curve in 60 seconds (iAUC) were then generated. The perfusion parameters acquired on DCE MR images were compared among the groups by using the analysis of variance test.Results:K(trans), k(ep), and iAUC values in patients with pancreatic cancer (0.042 min(-1) ± 0.023 [standard deviation], 0.761 min(-1) ± 0.529, and 2.841 mmol/sec ± 1.811, respectively) were significantly lower than in patients with a normal pancreas (0.387 min(-1) ± 0.176, 6.376 min(-1) ± 2.529, and 7.156 mmol/sec ± 3.414, respectively) (P < .05 for all). In addition, k(ep) values of PNETs and normal pancreas also differed (P < .0001), and K(trans), k(ep), and iAUC values of pancreatic cancers and PNETs differed significantly (P < .0001, P = .038, and P < .0001, respectively).Conclusion:Results of timing bolus DCE MR imaging with the radial KWIC sequence from routine examinations can be postprocessed to yield potentially useful perfusion parameters for the characterization of pancreatic diseases.© RSNA, 2012.
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ABSTRACT: MR imaging has unique benefits for evaluating the liver because of its high-resolution capability and ability to permit detailed assessment of anatomic lesions. In uncooperative patients, motion artifacts can impair the image quality and lead to the loss of diagnostic information. In this setting, the recent advances in motion-resistant liver MR techniques, including faster imaging protocols (e.g., dual-echo magnetization-prepared rapid-acquisition gradient echo (MP-RAGE), view-sharing technique), the data under-sampling (e.g., gradient recalled echo (GRE) with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA), single-shot echo-train spin-echo (SS-ETSE)), and motion-artifact minimization method (e.g., radial GRE with/without k-space-weighted image contrast (KWIC)), can provide consistent, artifact-free images with adequate image quality and can lead to promising diagnostic performance. Understanding of the different motion-resistant options allows radiologists to adopt the most appropriate technique for their clinical practice and thereby significantly improve patient care.BioMed Research International 08/2014; 2014:142658. DOI:10.1155/2014/142658 · 2.71 Impact Factor
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ABSTRACT: Object To assess the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI)-derived pharmacokinetic parameters between two contrast agents in a murine orthotopic pancreatic cancer model and to evaluate the tumor heterogenity and the potential association between kinetic parameters and angiogenic markers such as the microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression by immunohistochemistry.Magnetic Resonance Imaging 08/2014; DOI:10.1016/j.mri.2014.08.014 · 2.02 Impact Factor
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ABSTRACT: The aim of this study was to successfully establish an orthotopic murine model using two different human pancreatic adenocarcinoma cell lines and to propose a 3.0 tesla MRI protocol for noninvasive characterization of this model. SW1990 and MIAPaca-2 tumor cells were injected into the pancreas of BALB/C nu/nu mice. Tumor growth rate and morphological information were assessed by 3.0 tesla MRI (T1WI, T2WI and DC E-MRI) and immunohistology. Proliferation of SW1990 was significantly faster than that of MIAPaca-2 (P=0.000), but MIAPaca-2 mice had a significantly shorter survival than SW1990 mice (41 days and 44 days respectively, P=0.027). MRI could reliably monitor tumor growth in both cell lines: the tumors exhibiting a spherical growth pattern showed a high-intensity signal, and the SW1990 group developed significantly larger tumors compared with the MIAPaCa-2 group. There were no statistical differences between the two groups in which tumor size was assessed using electronic calipers and an MRI scan (P=0.680). Both tumors showed a slow gradual enhancement pattern. Immunohistochemistry demonstrated tumor tissues showing high expression of Ki-67. This model closely mimics human pancreatic cancer and permits monitoring of tumor growth and morphological information by noninvasive 3.0 tesla MRI studies reducing the number of mice required.Experimental Animals 07/2014; 63(4). DOI:10.1538/expanim.13-0086 · 1.17 Impact Factor