| [Objective]1. To explore the role of F-FDG PET/CT image in pancreatic benign and malignant lesions.2. To discuss the staging value of 18F-FDG PET/CT image in patients with pancreatic cancer.3. To analyse the value of CA19-9 in diagnosing pancreatic cancer.[Materials and Methods]1. Study objective1.1 Control group10 healthy subjects underwent 18F-FDG PET/CT scanning was selected as control group. All patients had normal results of the clinical examination, X-ray, B-ultrasound and serum tumor makers. All people had no past history and present history of pancreatic disease.1.2 Patient group59 patients with space-occupying lesions of the pancreas were selected for this study including 40 men and 19 women, aged from 15 to 82 years old, with a mean age of 57.2 years old. Among 59 patients,38 patients were diagnosed of pancreatic cancers, the other 21 patients of benign diseases. Pancreatic cancer primary lesions were confirmed by operation, pathologic examination. The metastases from pancreastic cancer or benign diseases of pancreas were confirmed by pathologic examination, multi-modality imaging or clinical follow-up. The duration of follow-up was more than 6 months.2. Main equipments and imaging agentDiscovery LS PET/CT Scanner and PETtrace cyclotron as well as chemical synthesis module tracerlab F-X F-N were from General Electric Company,18F-FDG was produced by PET Trace FDG Microlab automatic synthesis. Radiochemical purity of 18F-FDG was determined using high pressure liquid chromatography. And its radiochemical purity was over 95%.3. Imaging methods and acquisition conditionsAll patients underwent PET/CT scanning had fasted for more than 6 hours. The glucose levels were controlled under 6.7mmol/L. Patients received orally 600ml of 1.5% diatrizoate before injection for intestinal observation and received 400ml diatrizoate before scanned in 5 minutes for the filling of stomach. Each patient received an intravenous injection of 5.5 MBq/kg of 18F-FDG 60 minutes prior to the PET/CT scan. After about 60 minutes of relaxed rest in a supine position in dark room without visual or acoustic stimulations, the patients were asked to void before the start of acquisition. The image acquisition included non-enhanced CT scan and PET scan covered the range from the head to the middle thigh, scanning of both lower extremities if needed. And the CT scan conditions were:140kV,160mA, pitch0.75, 0.8second for tube lap rotation,5mm thickness, the emission scan time was 4 minutes per bed.4. Image reconstruction and image fusionThe PET images were reconstructed by OS-EM method and images attenuation correction used CT data. CT images were reconstructed by the standard reconstrucion method. The reconstructed slice thickness was 4.25mm. The PET and CT images were transmitted to Xeleris workstation to have the frame to frame image fusion display.5. Image analysis and diagnostic criteria5.1 Qualitative analysisPET/CT images were relied on visual inspection by two experienced senior physicians. The pancreatic caner diagnosis criteria included:①lesions located in the pancreas with higher 18F-FDG uptake than the normal pancreatic tissues were considered as malignant;②Pancreatic lesions showed diffuse distribution with high 18F-FDG uptake。5.2 Semi-quantitative AnalysisLesions with abnormal 18F-FDG uptake were identified by two experienced senior physicians of PET/CT. The standardized uptake value (SUV) was calculated with the PET scanning software and average value in the ROI was measured and recorded for each patient.6. Serum carbohydrate antigen 19-9(CA19-9) determinedBAYER centaur automated chemiluminescence immunoassay system which made in USA was used to detect serum CA19-9 levels. The level of 40 cases of healthy serum CA19-9 is (17.28±7.33). Normal serum level of CA19-9 was less than 32U/ml.7. The diagnostic criteria of 18F-FDG PET/CT combined with CA19-9Both are abnormal, the united diagnosed as positive; have a normal or if the two were normal, the combined diagnosis was negative.8. Statistical analysisAll data calculations were performed using SPSS, version 13.0, and P values of less than 0.05 were considered as statistical significance. [Results]1. Control groupIn ten persons, the brain is one of organ with high F-FDG uptake, especially in gray matter. Radioactive distribution in left and right cerebral and cerebellar is symmetry. Some people show intensive uptake of F-FDG in salivary gland and tonsils. Radioactive distribution in the lungs is low distribution, and some of left ventricular myocardial shows significant uptake of radioactivity. Radioactivity in the bilateral=renal, pelvis, ureters and bladder is very high. There is a mild uptake in the liver, spleen and bone marrow. Pancreas has no abnormal 18F-FDG uptake, and the SUV is (1.18±0.28).18F-FDG in abdominal omentum and mesenteric is low. Radioactivity gathered can sometimes be seen in small intestine and colorectal. No soft tissue mass or morphological abnormality in peritoneum can be observed on CT scan.2. Patient group2.1 Pancreatic cancer groupAmong the 59 patients with space occupying pancreatic lesions,38 patients were diagnosed as pancreatic cancers basing on operation and pathologic examination, others of benign diseases.2.2 18F-FDG PET/CT diagnose pancreatic cancerAmong the 59 patients,42 patients showed 18F-FDG high uptake in lesions,37 of them were pancreatic cancer,3 pancreatitis,1 pancreatic tuberculosis and 1 islet cell tumor. PET/CT scanning showed normal 18F-FDG uptake in 17 patients, in which 1 moderately differentiated adenocarcinoma in the head of pancreas, and others benign. Sensitivity, specificity, accuracy, positive and negative predictive value of 18F-FDG PET/CT in detecting pancreatic cancers were 97.4%,76.2%,89.8%,88.1%, 94.1% respectively. SUV in pancreatic cancer, control group and benign pancreatic diseases had significant difference (P= 0.000, P=0.003). SUV in control group and benign pancreatic diseases had no signigicant difference (P=0.052).2.3 Serum levels of CA19-9 diagnose pancreatic cancerAmong the 59 patients,42 patients had high level of CA19-9,34 were pancreatic cancers, other benign.17 patients had normal of CA19-9, but 4 were pancreatic cancer. The sensitivity, specificity, accuracy, positive and negative predictive value of CA19-9 was, respectively,89.5%,61.9%,79.7%,81.0%,76.5% respectively. CA19-9 between pancreatic cancer and benign pancreatic diseases had significant difference (t=2.340, P=0.025)2.418F-FDG PET/CT combined with CA19-9 diagnose pancreatic cancerIn 59 patients,35 patients had 18F-FDG PET/CT high uptake in the lesions with abnormal CA19-9,33 patients were pancreatic cancer.7 patients had 18F-FDG PET/CT high uptake but with normal CA19-9,4 were pancreatic cancer.10 patients with normal 18F-FDG PET/CT uptake and CA19-9 were confirmed as pancreatic benign. Another 7 patients with normal 18F-FDG PET/CT scanning had high levels of CA19-9, only one was pancreatic cancer. Sensitivity, specificity, accuracy, positive and negative predictive value of 18F-FDG PET/CT combined with CA19-9 was 86.8%,90.5%,88.1%,94.3%,79.2%, respectively.2.5 The value of F-FDG PET/CT in detection of metastases and staging2.5.1 Lymph nodes metastasesAmong the 38 pancreatic cancer patients,18F-FDG PET/CT discovered 14 cases of regional lymph node (LNs) metastasis, and 7 cases with distant LNs metastases. PET/CT identified 1 patients had distant LNs metastases without regional LNs metastases. The SUV between patients with LNs metastases and without LNs metastases had no significant difference (t=0.057, P= 0.955)2.5.2 Distant metastases Among the 38 patients, F-FDG PET/CT discovered 15 patients who had organs and/or tissue metastases.9 cases had metastasis to a single organ or tissue, liver metastases in 6 cases, adrenal metastasis in 1 case, ileal metastasis in 1 case, bone metastasis in 1 case.6 cases of multiple organs and/or tissue metastasis, in which violations of the right adrenal gland and two kidneys in 1 case, liver and bone metastasis in 2 cases, liver metastasis and sigmoid colon in 1 case, liver, right adrenal, and multiple bone metastasis in 1 case, right lower lung and right adrenal glands, ovaries with multiple bone metastasis in 1 case.In the patients with distant metastasis,10 cases had hepatic metastasis. In patients between hepatic metastases and without hepatic metastasis SUV had no significant difference (t= 0.606, P= 0.549).40.0%(6/15) patients with lymph nodes metastases had hepatic metastases,17.4%(4/23) patient had hepatic metastases without lymph node metastasis. There was 34.5% of patients (10/29) had vascular invasion with hepatic metastases, and 9 patients without vascular invasion had no hepatic metastasis.2.5.3 The influence of 18F-FDG PET/CT in clinical diagnosis and staging18F-FDG PET/CT changed the diagnosis of 6 patients.9 cases of 38 patients (23.7%) also changed the staging which changed treatment plan. In these 9 cases,4 cases of stage 0,2 cases of stage IIAand 1 cases of stage IIB was raised to stage III,1 case of stage 0 is raised to stage IB, and 1 case of stage 0 is raised to stage II A.2.6 Resectability evaluation by 18F-FDG PET/CT,abdominal CT in pancreatic cancer patients (In accordance with the standards of the 2010 NCCN)20 patients underwent surgical exploration, only 4 patients were respectable.Among 20 patients,18F-FDG PET/CT predicted 9 patients could surgical resection, others were unresectable. Accuracy of surgical resection or unresectable predicted by 18F-FDG PET/CT was 75.0%(15/20) In 20 patients,6 pancreatic cancer had invation of peripheral vascular discoved by abdominal CT. Accuracy of surgical resection or unresectable predicted by abdominal CT was 50.0%(10/20)2.7 The significance of serum CA19-9 in pancreatic cancer surgeryAmong 38 patients, only 4 patients could perform tumor complete resection (1 in IA stage and 1 in IIA stage,2 in IB stage), others unresectable (11 in III stage,23 in IV stage). Serum CA19-9 level in respectable and unrespectable pancreatic cancer patients had no significant difference (t=0.268, P=0.790).[Conclusions]1.18F-FDG PET/CT scans play an important role in distinguishing malignant from benign lesions of the pancreas. It has high sensitivity, specificity, accuracy, positive and negative predictive value of pancreatic cancer.2.18F-FDG PET/CT imaging can provide a comprehensive clinical stage. In N staging,18F-FDG PET/CT imaging can be more fully discovered the presence of lymph node metastasis; in M staging,18F-FDG PET/CT help find out more t organ metastasis, thus providing more accurate clinical Stage.18F-FDG PET/CT imaging changed the clinical stage (especially the N, M stage), due to discover of more lesions, thereby affecting the choice of treatment.3. Compared with abdominal CT, F-FDG PET/CT have more accuracy in assessing respectable or unrespectable of pancreatic cancer.4. Serum CA19-9 measurement is conductive to 18F-FDG PET/CT diagnosis of pancreatic cancer. |
PDF Full Text Request