# Application of Image Fusion in Diagnosis and Treatment of Liver Cancer
## 5 Clinical Applications of Image Fusion in Liver Cancer Diagnosis and Treatment
### CT/MRI  
#### 5.2.1 Detection of Intrahepatic Cholangiocarcinoma  
Intrahepatic cholangiocarcinoma(ICC) is the second most common hepatic malignant tumor type after hepatocellular carcinoma, which is characteristically associated with invasive growth, the occurrence of satellite foci and intrahepatic metastasis [162]. Preoperative imaging findings of intrahepatic cholangiocarcinoma foci and their sub-foci and accurate delineation of the boundaries of tumor lesions provide the basis for good surgical results. To improve the long-term survival rate of patients with bile duct cell carcinoma, the elucidation of the spatial anatomical relationships of bile duct cell carcinoma foci with intrahepatic portal vein and hepatic venous systems, and an improvement of the R0 resection rate, are necessary steps.  
Currently, multistage-enhanced CT and dynamic-enhanced MRI are commonly used in clinical practice for the detection of intrahepatic cholangiocarcinoma. These two technologies have the following disadvantages: the diagnostic rate for small tumor lesions \(<\)1 cm is not high, and an accurate  
Figure 3: A 51-year-old male. (**a**,**b**) Contrast-enhanced computed tomography (CT) indicates a liver tumor located in segment 7. Arterial enhancement and delay washout were observed. (**c**) A hypoechoic lesion in Ultrasonography (US). (**d**) Real-time US was successfully matched with immediately acquired pre-ablation 3 DUS. (**e**) Real-time US was matched with pre-ablation CT volume images successfully. (**f**) Ablation was applied under the guidance and monitoring of US. (**g**) Contrast-enhanced ultrasonography (CEUS) was performed and fused with pre-ablation 3 DUS. The ablation zone completely covered the target tumor and the 5-mm ablative margin. (**h**) CEUS fused with pre-ablation CT indicated the ablation zone completely covered the target tumor and the 5-mm ablative margin. (**i**) Subsequent contrast-enhanced CT within three months confirmed that the tumor had been completely ablated [164].  
display of tumor boundaries when the lesion differentiation degree is low and the capsule is incomplete, is difficult. The liver-specific contrast agent Gd-EOB-DTPA-enhanced MRI scan has the advantage of clearly displaying tumor lesion boundaries and intrahepatic microscopic lesions. However, due to the length of time required for MRI, images of intrahepatic vessels are likely to contain artifacts due to respiratory non-coordination [175]. With an extensive clinical application of medical image fusion technology, researchers have circumvented the disadvantages of the above techniques via the preoperative fusion of enhanced CT/MRI imaging in ICC. Fusion imaging allowed the determination of whether or not the lesion invades important hepatic vessels as well as establishment of the anatomical relationship between cholangiocarcinoma and satellite sub-focal lesions.  
In other words, the technology facilitated the quantitative evaluation of whether main and sub-focal lesions were in the same tumor-bearing liver segment, and thus the possibility of combined vascular resection. In this way, preoperative assessment could be used to effectively guide whether to perform regular segment resection, combined segment resection or enlarged lobectomy, leading to the avoidance of unexpected situations, such as postoperative liver insufficiency and liver failure.