| Objective13patients with mass-forming type intrahepatic cholangiocarcinoma were scanned in the3. OT magnetic resonance equipment, using hepatobiliary-specific gadolinium contrast agent Gd-BOPTA.The unenhanced, early arterial, late arterial, portal, equilibrium, delayed phases and hepatobiliary phase of60-90minutes are collected in all the patients. This research is aimed to discover the characteristics of mass-forming type intrahepatic cholangiocarcinoma on the images of hepatobiliary phase. We also draw the time-signal intensity curves of the edge, central part of the tumor as well as the hepatic parenchyma to evaluate the value of the curves.Methods13patients with mass-forming type intrahepatic cholangiocarcinoma were collected. Dynamic contrast-enhanced MR examinations were carried out on all the patients, using hepatobiliary-specific gadolinium contrast agent Gd-BOPTA in the Radiology Department of Shandong Provincial Hospital.10the tumors are confirmed by surgery,3by biopsy. There are7males and6females, aged42-83years, with an average age of60.8±12.1years.The scanning were performed on Siemense MAGNETOM verio3. OT magnetom equipment, using the hepatobiliary-specific gadolinium contrast agent Gd-BOPTA named MultiHance. The amount of MultiHance is calculated according to0.2ml/kg body weight, injected with German ULRICH binoculars high-pressure syringe at the rate of2.5ml/s. All the patients underwent the unenhanced and dynamic contrast-enhanced scanning. The unenhanced scanning include the following sequences:①Axial Turbo Spin Echo T1WI;②Axial Turbo Spin Echo T2WI;③Coronal Turbo Spin Echo T2WI;④Axial Gradient Recalled Echo in/out-phase T1WI;⑤Diffusion weighted imaging;⑥2D MRCP,4-8images were collected with multiple angles. There was prescan before dynamic contrast-enhanced scanning, using the Volume Interpolated Body Examination sequence, scanning parameters:TR:3.9ms, TE:1.4ms, Band Width:352Hz, Matrix:182X320, FOV:309X251, Slice Thickness:3.0mm, intersection gap:0.6mm, NEX:2, collecting time:17s. Then MultiHance was injected, early arterial phase (15s), late arterial phase(25s), portal phase (59.5±3.7s), equilibrium phase(1min40.5s±9s) and hepatobiliary phase (60-90min)were collected with the same parameters as the prescan.Two radiologists experienced at diagnosis of abdominal diseases retrospectively read the MR images of all patients. Information below were evaluated:(1)The image characteristics of mass-forming type intrahepatic cholangiocarcinoma on hepatobiliary phase images;(2)Draw the time-signal intencity curves of tumor edges, tumor centrals and hepatic parenchyma;(3)The dynamic enhancement characteristics and tumor-associated signs of mass-forming type intrahepatic cholangiocarcinoma on precsan images and dynamic contrast-enhanced images.Result(1) Image characteristics of mass-forming type intrahepatic cholangiocarcinoma on hepatobiliary phase images:tumors were hypointense on the peripheral and present a clear demarcation with hepatic parenchyma. The hypointense rims were where present contrast enhancement at the peripheral on arterial phase. Complete filling of the tumors with contrast material were observed on hepatobiliary phase.(2) Trends of time-signal intensity curves of the tumor edges, tumor centers and hepatic parenchyma analyzed. Curve of tumor edge presents a upward trend at the early phase, reach peak at the equilibrium phase, then it go downward, with rate of decline slow down after. Curve of tumor center presents a upward trend at the early phase, reach a high value at the equilibrium phase, then it go upward slowly till peak and then go downward slowly. The peak value of tumor center is much lower than peak of tumor edge. Curve of hepatic parenchyma presents a upward trend at the early phase, reach a high value at the portal phase, then go downward slowly or reach a stable plateau. The difference between enhancement rate of tumor edges, tumor centrals and hepatic parenchyma has statistical significance. The enhancement rate of tumor edges is the highest, and then hepatic parenchyma, tumor centrals is the lowest.(3)The dynamic enhancement characteristics and tumor-associated signs of mass-forming type intrahepatic cholangiocarcinoma on prescan images and dynamic contrast-enhanced images:among all13patients11were isolated leisions,2were surrounded by satellite nodules; among all13patients,4were located on the left lobe,9on the right. Tumors were irregular or round-like on the shape with the diameter2.6-7.3cm, average diameter was4.4±1.68cm; the satellite nodules were round-like with the diameter0.5-2cm. Tumors were hypointense on T1WI and hyperintense on T2WI. On dynamic contrast-enhanced MR, the tumor presents contrast enhancement at the peripheral on arterial phase, with progressive and concentric filling on late and delayed images. However, complete filling of the tumor with contrast material was not observed. The tumor-associated signs include:hepatic lobe atrophy was seen in4of all13patients, while tumor adjacent liver capsule depression was observed in3.12were accompanied by dilatation of adjacent bile ducts. Hepatic arteries were involved in12, while portal vein in9. Transient hepatic intensity difference were seen in2patients.11patients had intra-abdominal and retroperitoneal lymph node metastasis,1patient had peritoneal metastases and ascites.Conclusion(1)On hepatobiliary phase images obtained at60-90minutes after injection of contrast material, the tumor presents characteristic features:The tumor is hypointense on the peripheral and presents a clear demarcation with hepatic parenchyma. Complete filling of the tumors with contrast material were observed on hepatobiliary phase.(2)Trends of time-signal intensity curves of the tumor edges, tumor centers and hepatic parenchyma were analyzed. Conclusions may be that the enhancement patterns of mass-forming type intrahepatic cholangiocarcinoma are due to different cellular components between tumor edge and center. Rich cellular components are found on the edge, while less in the center. That’s why different speed of clearance was observed.(3)Routine dynamic contrast-enhanced scanning images of patients with mass-forming type intrahepatic cholangiocarcinoma in the3. OT magnetic resonance equipment using Gd-BOPTA are similar to those with non-hepatobiliary-specific gadolinium contrast agent. The tumor presents contrast enhancement at the peripheral on arterial phase, with progressive and concentric filling on late and delayed images. However, complete filling of the tumor with contrast material was not observed. |
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