Quantitative imaging is the analysis of retrieved numeric data from images with the goal of reducing subjective assessment. It is an increasingly important radiologic tool to assess treatment response in oncology patients. Quantification of response to therapy depends on the tumor type and method of treatment. Anatomic imaging biomarkers that quantify liver tumor response to cytotoxic therapy are based on temporal change in the size of the tumors. Anatomic biomarkers have been incorporated into the World Health Organization criteria and the Response Evaluation Criteria in Solid Tumors (RECIST) versions 1.0 and 1.1. However, the development of novel therapies with different mechanisms of action, such as antiangiogenesis or radioembolization, has required new methods for measuring response to therapy. This need has led to development of tumor- or therapy-specific guidelines such as the Modified CT Response Evaluation (Choi) Criteria for gastrointestinal stromal tumors, the European Association for Study of the Liver (EASL) criteria, and modified RECIST for hepatocellular carcinoma, among many others. The authors review the current quantification criteria used in the evaluation of treatment response in liver tumors, summarizing their indications, advantages, and disadvantages, and discuss future directions with newer methods that have the potential for assessment of treatment response. Knowledge of these quantitative methods is important to facilitate pivotal communication between oncologists and radiologists about cancer treatment, with benefit ultimately accruing to the patient.

https://pubs.rsna.org/doi/pdf/10.1148/rg.336135511

Assessment of Liver Tumor Response to Therapy: Role of Quantitative Imaging

Perfusion CT of head and neck cancer.

In the genomics era, our main goal should be to identify large and meaningful differences in small, molecularly selected groups of patients. Classical phase I, II and III models for drug development require large resources, limiting the number of experimental agents that can be tested and making the evaluation of targeted agents inefficient. There is an urgent need to streamline the development of new compounds, with the aim of identifying "trials designed to learn", which could lead to subsequent "trials designed to conclude". Basket trials are often viewed as parallel phase II trials within the same entity, designed on the basis of a common denominator, which can be a molecular alteration(s). Most basket trials are histology-independent and aberration-specific clinical trials. Umbrella trials are built on a centrally performed molecular portrait and molecularly selected cohorts with matched drugs, and can include patients' randomisation and strategy validation. Beyond new designs, new end-points and new evaluation techniques are also warranted to finally achieve methodology and clinical improvements, in particular within immunotherapy trials.

https://err.ersjournals.com/content/errev/23/133/367.full.pdf

New clinical research strategies in thoracic oncology: clinical trial design, adaptive, basket and umbrella trials, new end-points and new evaluations of response

Purpose
Multiple imaging techniques are nowadays available for clinical in-vivo visualization of tumour biology. FDG PET/CT identifies increased tumour metabolism, hypoxia PET visualizes tumour oxygenation and dynamic contrast-enhanced (DCE) CT characterizes vasculature and morphology. We explored the relationships among these biological features in patients with non-small-cell lung cancer (NSCLC) at both the patient level and the tumour subvolume level.

/pdf/multiparametric-imaging-of-patient-and-tumour-heterogeneity-o7bvy4ckjh.pdf

Multiparametric imaging of patient and tumour heterogeneity in non-small-cell lung cancer: quantification of tumour hypoxia, metabolism and perfusion.

Twenty years ago, theoretical developments were initiated to model the behavior of the NMR transverse relaxation rates in presence of vessels. These developments enabled the MRI-based mapping of mean vessel diameter, microvascular density, and vessel size index with comparable results to those obtained by a pathologist. The transfer of these techniques to routine clinical use has been hindered by the unavailability of the required sequences, namely fast gradient-echo spin-echo sequences. Based on the increasing accessibility of such sequences on MRI scanners over recent years, we review the principles governing microvascular MRI, the validation studies, and the applications that have been tested worldwide by several teams. We also provide some recommendations on how to measure microvessel caliber and density with MRI.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/mrm.25396

Imaging the microvessel caliber and density: Principles and applications of microvascular MRI

OBJECTIVE. This article summarizes the current status of CT perfusion in oncologic imaging, including lesion characterization, staging, prediction of patient outcome or response to therapy, assessment of response to different therapies, and evaluation of tumor relapse. Technical limitations and drawbacks of CT perfusion are also discussed. CONCLUSION. Tumor angiogenesis is essential for cancer growth and provides an attractive target for oncologic therapies. CT perfusion is an emerging imaging tool that provides both qualitative and quantitative information regarding tumor angiogenesis.

https://www.ajronline.org/doi/pdf/10.2214/AJR.11.8476

Miguel Garrido

Papers

CT Perfusion in Oncologic Imaging: A Useful Tool?