Interventional radiology has contributed to an improvement in life expectancy in patients with malignant hepatic tumors. Radiofrequency ablation (RFA) and transarterial chemoembolization (TACE) for hepatocellular carcinoma have been widely performed. Sonography, computed tomography (CT), and magnetic resonance imaging (MRI), as well as several image fusion techniques, are performed to evaluate the completeness of the procedure and treatment course. The goal of RFA is complete ablation of a tumor with an adequate circumferential safety margin for the treatment; however, assessment of technical success is sometimes difficult in cases without the combination of conventional TACE (cTACE). The goal of TACE is also complete embolization of a tumor with a safe margin. In cTACE with iodized oil and gelatin sponge particles, the embolized area can be easily assessed on CT or cone-beam CT because iodized oil is highly radiopaque. However, peritumoral recurrence is frequently missed due to beam hardening artifacts from iodized oil in the tumor, especially in cases treated with superselective cTACE. Therefore, CT and MRI should be performed in turn in the follow-up. On the other hand, in TACE with drug-eluting beads (DEB-TACE), CT and MRI can show similar residual tumor and rating of treatment results.

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Lung cancer is the leading cause of cancer death all over the world, and metastatic lung cancer is also the cause of death in many patients with malignancies. The first-line treatment is surgical resection, but fewer than 30% of the patients are surgical candidates. Lung radiofrequency ablation (RFA) can be an alternative treatment, and the number of patients undergoing RFA will increase. Therefore, we should be well aware of the imaging findings after lung RFA. Immediately after RFA, ground-glass opacity with thin rim appears around the tumor. It changes to dense consolidation with non-contrast enhancement 1-3 months after wards. At this time, the diameter of the consolidation can be larger than the baseline tumor diameter. It decreases in size gradually and can be the same or smaller compared to the baseline tumor size at approximately 6 months after wards. If the size of the ablation zone does not become smaller, a contrast enhanced nodule appears around the ablation zone, or high FDG uptake can be seen adjacent to the ablation zone, it should be diagnosed as residual or recurrent tumor. Most frequent complication is the pneumothorax. Other complications including air-embolism, interstitial pneumonia, pulmonary artery pseudoaneurysm, bronchopulmonary fistula and tumor seeding can also be seen.

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Ablative therapies such as radiofrequency ablation (RFA) or cryoablation are minimally-invasive treatment options for small renal cell carcinomas (RCCs). Usually, RFA is performed under computed tomography (CT) guidance, whereas cryoablation is carried out under CT or magnetic resonance imaging (MRI) guidance. Owing to the recent advancements in imaging modalities and the widespread use of screening tests, the number of cases with small RCCs that are being detected is increasing. Consequently, an increasing number of patients with comorbid disease, or hereditary RCC, are receiving ablative therapy in Japan. However, there are some difficulties associated with this method, and it is important that we critically evaluate the effects of treatment after ablative therapy. Furthermore, during the procedure itself, it remains difficult to determine whether the ablated area is sufficient or not using only CT or MRI guidance. This chapter focuses on the perioperative imaging of ablative therapy for RCCs including the management of complications.

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For the treatment of aortic diseases, abdominal endovascular abdominal aortic pair (EVAR) and thoracic endovascular aortic repair (TEVAR) have been widely used. More than a half of abdominal aortic aneurysms are now treated with EVAR. Thoracic descending aortic aneurysm is treated with TEVAR as the first choice.
In recent years, stent-graft treatment has been approved for insurance purposes to aortic dissection and its adaptation has spread further.
Unlike surgical replacement, stent-graft is a treatment that leaves a pathologic aorta even after treatment,and secondary intervention is more frequent than after surgical replacement. Therefore, follow-up imaging is required over a long period of time, and the role of radiologists is also important.
This review provides imaging findings after stent-graft placement. We also describe criteria to evaluate endoleaks, re-interventions or surgical treatments.

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Following up patients after coil embolization with non-invasive imaging such as CT or MRI is important to evaluate recanalization, surrounding and distal organ ischemia and complications, but can be difficult due to metal artifact or other factors. In this article, the characteristics of X-ray, CT and MRI to assess post-embolization state were addressed. The recent trend including dual energy CT, metal artifact reduction algorithm on CT, and sequences for MR angiography were summarized with some clinical cases.

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