Image-guided Treatment in the Hepatobiliary System: Role of Imaging in Treatment Planning and Posttreatment Evaluation

Abstract

In the past decade, image-guided targeted treatments such as percutaneous ablation, intra-arterial embolic therapies, and targeted radiation therapy have shown substantial promise in management of hepatobiliary malignancies. Imaging is integral to patient selection, treatment delivery, and assessment of treatment effectiveness. Preprocedural imaging is crucial and allows local tumor staging, evaluation of surrounding structures, and selection of suitable therapeutic options and strategies for treatment delivery. Postprocedural imaging is required to monitor therapeutic success, detect residual or recurrent disease, and identify procedure-related complications to guide appropriate future therapy. Technical innovations in cross-sectional imaging techniques such as computed tomography (CT) and magnetic resonance (MR) imaging, combined with advances in image postprocessing and new types of contrast agents, allow precise morphologic assessment and functional evaluation of hepatobiliary tumors. Advanced postprocessing techniques such as image fusion and volumetric assessment not only facilitate procedural planning and treatment delivery but also enhance posttreatment imaging surveillance. In addition, molecular imaging techniques such as fluorodeoxyglucose positron emission tomography (PET), PET/CT, and PET/MR imaging offer opportunities to evaluate various physiologic properties of tumors.

Indian College of Radiology and Imaging Guidelines on Interventions in Hepatocellular Carcinoma

“…The first follow-up imaging is performed 4 to 8 weeks after imaging, usually using multiphase CT or MRI. 105 106 107 Successful ablation is seen as complete T1/T2 hypointensity and hypoenhancement of the tumor as well as the safety margin (1cm beyond the tumor). Thus, the final ablation zone is larger than the original tumor.…”

Magnetic Resonance-Guided Focused Ultrasound in the Treatment of Colorectal Cancer Liver Metastases

“…Radiological imaging is used in a variety of manners in treating CRLM: including, to diagnose a condition, stage the disease, to locate extra-hepatic metastases, for treatment planning, for interventional image-guided procedures, and for post-treatment evaluation [57]. MRgHIFU requires additional MRI sequence protocols, compared to general diagnostic MRI.…”

“…CRLM radiotherapy has often been limited by liver parenchyma radio-sensitivity. External beam radiation doses of 70-90 Gy needed for CRLM and HCC tumor treatment exceeds tolerance limits of 35 Gy for radiationinduced liver disease (RILD) [57,134] that can lead to liver failure and death [25]. The condition occurs two to sixteen weeks after treatment, is identified by ascites, high levels of alkaline phosphatases, and high levels of liver transaminases [135].…”

Interventional Molecular Imaging

“…The usefulness of this multimodality fusion has been demonstrated for both image-guided biopsies and tumor ablations (10,11). However, this technique is limited by the need to use previously obtained PET images and the difficulty of registration (12).…”