Clinical application of 3.0 T proton MR spectroscopy in evaluation of pancreatic diseases

Transcription

1 Clinical application of 3.0 T proton MR spectroscopy in evaluation of pancreatic diseases Award: Cum Laude Poster No.: C-1762 Congress: ECR 2012 Type: Scientific Paper Authors: T. Su, E. Jin; Beijing/CN Keywords: Pancreas, MR-Spectroscopy, MR DOI: /ecr2012/C-1762 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 14

2 Purpose 1.Pancreatic diseases (i.e. acute pancreatitis, chronic pancreatitis and pancreatic cancer) are common. However, differentiating malignant from others could be difficult sometimes by existing methods[1-2]. It would be beneficial to devise new methods to do this. 2.Magnetic resonance spectroscopy (MRS) is a non-invasive technique that can characterize metabolites in vivo[3]. Proton MRS ( 1 H MRS)has been clinically applied in the brain, prostate, and breast, and can potentially monitor disease and predict progression[4] H MRS of pancreatic cancer showed a higher value of Chol+Unsat/Lip than that of normal pancreas in our previous study[5]. Therefore, the aim is to study the usefulness of 3.0 T 1 H-MRS in diagnosing pancreatic diseases. Methods and Materials Subjects: Pancreas spectroscopies of 70 subjects included normal pancreas ( n = 25), acute edematous pancreatitis (n = 15), chronic pancreatitis (n = 10) and pancreatic cancer ( n = 20). The 25 healthy volunteers with normal pancreas underwent the following exclusion criteria: history of pancreatic and biliary disorders, diabetes, any cancerous tumor, any systemic disease, upper abdominal surgery; use of pharmacological agents that alter fat content or metabolism; active weight loss in the previous 6 months All pancreatic disease patients were diagnosed clearly with proper methods. Acute edematous pancreatitis was based on clinical presentations, laboratory results. MRI follow-up helped in the confirmation of diagnosis after treatment. Chronic pancreatitis was based on clinical presentations, laboratory results. They were confirmed by endoscopic guided fine needle biopsy (4/10), ERCP(6/10). Pancreatic adenocarcinomas were histopathologically confirmed via surgery (8/20), endoscopic guided fine needle biopsy (12/20). MRS: Page 2 of 14

3 MRI and MRS were performed at 3.0 Tesla whole-body scanner using an 8-channel phased-array body coil. High-resolution images from the abdomen were collected to locate the pancreas before MRS. Localizing sequence in the transverse used T1WI with fat-suppression fast spoiled gradient recalled echo sequences [200 ms repetition time (TR), 2.7 ms echo time(te), number of excitations (NEX) 0.8]. 1 H MRS was acquired with single-voxel PRESS (TR 1250 ms/te 35 ms, NEX 8) under during free-breathing pattern. Volume of interest ( mm) placed in the head of the pancreas for normal pancreas and in the lesion of pancreas. Fat saturation bands were added around the voxel in order to eliminate the influence of surrounding fat. Fullwave at half maximum (FWHM) was limited to below 25 during automated optimization of shimming, and chemical shift selection (CHESS) was used for water suppression. Post-processing procedure of MRS and statistical analysis: Spectra were evaluated using a workstation (General Electric Advanced Development Workstation) equipped with commercial software (Spectral Analysis/General Electric 7.0; General Electric Medical Systems). The post-processing procedure included zero filling, Fourier transformation, and phase correction. The spectral appearances were analyzed, and metabolites visibility rates between pancreatic cancer and non-cancer group were compared. The ratio of cholesterol and the olefinic region of fatty acids (Chol+Unsat) peak height to lipid (Lip) peak height (Chol + Unsat/Lip) was calculated in each 1 H-MRS, and a ROC analysis was performed between the ratios of two groups. Results There were four resonance peaks in the spectra, i.e., Lip, Chol+Unsat, choline (Cho) and creatine#cr#. Metabolites visible statuses of MRS in non-cancer and cancer group were listed (Table 1).There were no significant difference in each metabolite visibility rate between pancreatic cancer and non-cancer group. The mean value of Chol + Unsat/Lip in 1 H-MRS was 0.199±0.095 for non-cancer group, 0.325±0.187 for pancreatic cancer group. Statistically significant difference was found in the values of Chol + Unsat/Lip ratios between cancer and non-cancer group (t = 2.855, Page 3 of 14

4 P = 0.009) (Table 2). MRS spectra of normal pancreas, acute edematous pancreatitis, chronic pancreatitis, pancreatic cancer and their location images were shown from Figure 1 to Figure 8. The area under the ROC curve (Figure 9) was 0.72 (P = 0.005). With ROC cut point setting to 0.295, the diagnostic sensitivity, specificity, accuracy for pancreatic cancer were 55 %, 86 %, 77 %, respectively. Images for this section: Table 1: Table1 Metabolites visible status of MRS in pancreatic cancer and non-cancer group Table 2: Table 2 The value of Chol + Unsat/Lip in pancreatic cancer and non-cancer group Page 4 of 14

5 Fig. 1: This spectrum is MRS of normal pancreas in a 40-year-old female subject. From right to left, it showed lipid (the highest one)at 1.3 ppm, creatine peak at 3.0 ppm, Choline peak (arrow) at 3.2 ppm, the C6 of cholesterol and the unsaturated olefinic region of fatty acids peak at ppm. Chol+Unsat/Lip= Page 5 of 14

6 Fig. 2: The location image of Figure 1 in T1WI illustrated the normal pancreatic head, and the white box was the voxel of interest. Page 6 of 14

7 Fig. 3: This spectrum is MRS of acute edematous pancreatitis,in a 46-year-old female patient. From right to left, it showed lipid (the highest one)at 1.3 ppm, creatine peak at 3.0 ppm, Choline peak (arrow) at 3.2 ppm, the C6 of cholesterol and the unsaturated olefinic region of fatty acids peak at ppm. Chol+Unsat/Lip= Page 7 of 14

8 Fig. 4: The location image of Figure 3 in T1WI illustrated the enlargement of pancreatic head, and the white box was the voxel of interest. The thickness of perirenal fascia was also noticed. Page 8 of 14

9 Fig. 5: This spectrum is MRS of chronic pancreatitis in a 45-year-old male patient. From right to left, it showed lipid (the highest one)at 1.3 ppm, Choline peak (arrow) at 3.2 ppm, the C6 of cholesterol and the unsaturated olefinic region of fatty acids peak at ppms. Chol+Unsat/Lip= Page 9 of 14

10 Fig. 6: The location image of Figure 5 in T1WI illustrated the enlargement of pancreatic head. Page 10 of 14

11 Fig. 7: This spectrum is MRS of pancreatic cancer in a 55-year-old female patient. From right to left, it showed lipid (the highest one)at 1.3 ppm, creatine peak at 3.0 ppm, Choline peak (arrow) at 3.2 ppm, the C6 of cholesterol and the unsaturated olefinic region of fatty acids peak at ppm. Chol+Unsat/Lip= 0.29 Page 11 of 14

12 Fig. 8: The location image of Figure 7 in T1WI illustrated a mass in the pancreatic head, and the white box was the voxel of interest. Page 12 of 14

13 Fig. 9: The ROC curve of diagnosing pancreatic cancer using the value of Chol + Unsat/ Lip in MRS Page 13 of 14

14 Conclusion 1 H-MRS of pancreatic cancer showed a higher ratio of Chol + Unsat/Lip, and this may be useful in differentiating pancreatic cancer from other pancreatic diseases. References [1] Fattahi R, Balci NC, Perman WH, et al. Pancreatic diffusion-weighted imaging (DWI): comparison between mass-forming focal pancreatitis (FP), pancreatic cancer (PC), and normal pancreas. J Magn Reson Imaging#2009#29(2): [2] Kim JK, Altun E, Elias JJ, et al. Focal pancreatic mass: distinction of pancreatic cancer from chronic pancreatitis using gadolinium-enhanced 3D-gradient-echo MRI. J Magn Reson Imaging#2007#26(2): [3] Soares DP.Law M. Magnetic resonance spectroscopy of the brain: review of metabolites and clinical applications. Clin Radiol#2009#64(1): [4] Mountford C, Lean C, Malycha P, et al. Proton spectroscopy provides accurate pathology on biopsy and in vivo. J Magn Reson Imaging#2006#24(3): [5] Su TH, Shen H, Jin EH, et al. Preliminary application of 3.0 T proton MR spectroscopy in diagnosis of patients with pancreatic cancer. Journal of clinical and expeirmental medicine#2011#10(13): Personal Information Page 14 of 14