VASCULAR AND INTERVENTIONAL RADIOLOGYR adiofrequency ablation (RFA) guided by medical imaging is now commonly used to treat a wide range of focal primary and metastatic tumors in solid organs, primarily the liver (1,2). The growing adoption and clinical implementation of this technique can be attributed to its minimal invasiveness, low morbidity, and cost efficiency (3). Thus, hepatic RFA has been adopted in consensus guidelines as a first-line therapy for primary cancer (eg, hepatocellular carcinoma) (4) and as a second-line therapy for metastatic tumors such as colorectal cancer (5,6).Despite various advantages, treatment efficacy remains challenging in some patient populations. This includes achieving complete ablation of tumors larger than 3 cm (1,2), where studies have suggested that RFA may be associated with higher tumor recurrence rates (7), in part due to the difficulty in achieving a periablational margin of more than 5 mm, which is associated with better clinical outcomes (8,9). Moreover, there is a growing amount of laboratory data supporting the contention that thermal ablation of normal liver required to achieve sufficient margins can increase Results: RFA performed after tumor cell injection induced increased metastatic tumor number (103 6 45 vs 52 6 44 [CT26], P = .009 and 87 6 51 vs 39 6 20 [MC38], P = .007), cellular proliferation (P , .001 for both), and intratumoral neovascularization (P , .001 for both), compared with the sham procedure. Tumor cell injection performed 1 day and 3 days after RFA also increased these indexes (P , .05), while no difference was demonstrated for cell injection 7 days after RFA (P . .05). Adjuvant c-Met or STAT3 inhibition reduced intrahepatic metastatic parameters after RFA to baseline (P , .03), equivalent to the sham group (P . .05). Conclusion:Radiofrequency ablation of normal liver promotes intrahepatic metastatic implantation and increased growth over a short-lived (1-3 days) temporal window in animal models. This phenomenon can be potentially neutralized with specific inhibition of pathways including hepatocyte growth factor/tyrosine-protein kinase Met and signal transducer and activator of transcription 3.

Bosniak 2F renal cystic lesions feature morphologic characteristics between Bosniak I and III categories, the majority of which remain benign. However, a minor part of Bosniak 2F lesions may progress to malignancy. The purpose of this study was to assess Bosniak 2F cystic lesions during follow-up examinations by CEUS. One-hundred-and-twelve out of 364 patients with Bosniak 2F lesions underwent follow-up CEUS examinations between February 2008 and February 2020. Twelve out of 364 patients underwent renal surgery without follow-up CEUS. The progression rate of Bosniak 2F renal lesions detected by CEUS accounted for 7.1% (8/112 patients) after a mean of 12.9 months. The first follow-up CEUS revealed 75% of progressions (6/8), the remaining 25% (2/8) of progressions were detected during second follow-up CEUS. Underlying clear-cell renal cell carcinoma was histopathologically validated in 5/8 progressive complex cystic renal lesions. Stable sonomorphologic features were observed in 92.1% (104/112 patients). CEUS depicts a promising diagnostic imaging modality in the diagnostic work-up and follow-up of complex renal cystic lesions at higher spatial and temporal resolutions than CT or MRI. Its excellent safety profile, its easy and repeatable accessibility, and low financial costs render CEUS an attractive and powerful alternative imaging tool for monitoring complex renal cystic lesions.

Tumor-associated macrophages (TAMs) represent the largest group of leukocytes within the tumor microenvironment (TME) of solid tumors and orchestrate the composition of anti- as well as pro-tumorigenic factors. This makes TAMs an excellent target for novel cancer therapies. The plasticity of TAMs resulting in varying membrane receptors and expression of intracellular proteins allow the specific characterization of different subsets of TAMs. Those markers similarly allow tracking of TAMs by different means of molecular imaging. This review aims to provides an overview of the origin of tumor-associated macrophages, their polarization in different subtypes, and how characteristic markers of the subtypes can be used as targets for molecular imaging and theranostic approaches.

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