Abstract: Objective:To evaluate the clinical value of Fluorine18fluorodeoxyglucose ( ¹⁸FFDG) positronemission temographycomputed tomography (PET-CT) examination in intrahepatic cholangiocarcinoma (ICC) staging.
Methods:The retrospective crosssectional study was conducted. The clinicopathological data of 190 patients with ICC who were admitted to the Eastern Hepatobiliary Surgery Hospital Affiliated to Naval Military Medical University from September 2013 to June 2016 were collected. There were 107 males and 83 females, aged from 37 to 79 years, with an average age of 57 years. There were 90 cases without distant metastasis undergoing surgery treatment and 100 with distant metastasis undergoing nonsurgical treatment. Patients underwent preoperative CT, magnetic resonance imaging (MRI), and PET-CT examination, and then received surgery or nonsurgery according to preference of patients and their family members. Observation indicators: (1) imaging features on preoperative CT, MRI, PET-CT examination; (2) treatment; (3) evaluation of tumor diameter, multiple tumors, macrovascular invasion, and bile duct invasion by three examinations in ICC staging of patients undergoing operation; (4) evaluation of regional lymph node metastasis by three tests in ICC staging of patients undergoing operation; (5) evaluation of distant metastasis in ICC staging by three tests. Measurement data with normal distribution were represented as Mean±SD, and comparison between groups was analyzed by single factor ANOVA and paired comparison was analyzed by SNK method. Measurement data with skewed distribution were described as M (range). Count data were described as absolute number or percentage, and comparison between groups was analyzed using the chi square test.
Results:(1) Imaging features on preoperative CT, MRI, PET-CT examination: all the 190 patients received routine upper abdominal CT, MRI, and systemic PET-CT examination before treatment. CT imaging of ICC showed inhomogeneous low density on plain scan, peripheral enhancement in arterial phase, persistent enhancement of tumor margin in portal phase, and sometimes mild to moderate centripetal enhancement. MRI imaging showed heterogeneous low signal on T1weighted imaging, uneven high, and slightly high signal on T2weighted imaging. Reinforcement on MRI is the same as CT. Transverse images, fusion transverse images and maximum intensity projection images of PET-CT imaging showed abnormal high FDG uptake around the tumor. (2)Treatment: 81 out of the 90 ICC patients with surgery treatment underwent hepatectomy and lymphadenectomy, and 9 underwent only tumor tissue biopsy and lymph node biopsy due to intraoperative finding of abdominal metastasis. Of the 100 nonoperated patients, 30 received systemic chemotherapy, 23 received local radiotherapy, and 47 gave up treatment. (3) Evaluation of tumor diameter, multiple tumors, macrovascular invasion, and bile duct invasion by three examinations in ICC staging of patients undergoing operation: the tumor diameters of ICC on CT, MRI and PET-CT were (6.8±2.8)cm, (6.9±2.9)cm, (7.2±2.8)cm, respectively. There was no significant difference among the three methods (F=0.085, P>0.05). CT, MRI, PET-CT had similar accuracy of 80.0%(72/90), 78.9%(71/90), 72.2%(65/90) on diagnosing multiple tumors, 87.8%(79/90), 92.2%(83/90), 94.4% (85/90) for macrovascular invasion, and 93.3%(84/90), 95.6%(86/90), 96.7%(87/90) for vascular and bile duct invasion, respectively, there was no significant difference in the above indicators between the three groups (X²=1.801, 2.662, 1.131, P>0.05). (4) Evaluation of regional lymph node metastasis by three examinations in ICC staging of patients undergoing operation: the accuracy of CT, MRI and PET-CT examination for lymph node metastasis was 62.2%(56/90), 68.9%(62/90), 86.7%(78/90) and sensitivity was 40.0%(16/40), 47.5%(19/40), 80.0%(32/40), respectively, showing significant differences between the three groups (X²=14.446, 14.666, P<0.05), showing a significant difference between CT and PET-CT examination (X²=14.134, 13.333, P<0.05), showing a significant difference between MRI and PET-CT examination (X²=8.229, 9.141, P<0.05). The sensitivity of CT, MRI and PET-CT examination for lymph node metastasis was 80.0%(40/50), 86.0%(43/50), 92.0%(46/50), showing no significant difference between the three groups (X²=2.990, P>0.05). (5) Evaluation of distant metastasis in ICC staging by three tests: there were 27, 34 and 100 cases with distant metastasis evaluated by CT, MRI and PET-CT examination, including 40 with supraclavicular lymph node metastasis, 32 with bone metastasis, 30 with mediastinal lymph node metastasis, 20 with hilar lymph node metastasis, 17 with pulmonary metastasis; 77 patients had more than 2 sites of metastasis. The accuracy of CT, MRI and PET-CT examination for distal metastasis in 190 ICC patients was 61.58%(117/190), 65.26%(124/190), 98.42%(187/190), respectively, with a significant difference between the three groups (X²=83.639, P<0.05), with a significant difference between CT and PET-CT examination (X²=80.592, P<0.05), between MRI and PET-CT examination (X²=70.284, P<0.05).
Conclusion:PET-CT examination makes up for the deficiency of CT and MRI in judging regional lymph node metastasis and distant metastasis, and contributes to the clinical staging of ICC.