Quantitative imaging biomarkers: a review of statistical methods for technical performance assessment.

Technological developments and greater rigor in the quantitative measurement of biological features in medical images have given rise to an increased interest in using quantitative imaging biomarkers to measure changes in these features. Critical to the performance of a quantitative imaging biomarker in preclinical or clinical settings are three primary metrology areas of interest: measurement linearity and bias, repeatability, and the ability to consistently reproduce equivalent results when conditions change, as would be expected in any clinical trial. Unfortunately, performance studies to date differ greatly in designs, analysis method, and metrics used to assess a quantitative imaging biomarker for clinical use.

The emerging science of quantitative imaging biomarkers terminology and definitions for scientific studies and regulatory submissions.

The development and implementation of quantitative imaging biomarkers has been hampered by the inconsistent and often incorrect use of terminology related to these markers. Sponsored by the Radiological Society of North America, an interdisciplinary group of radiologists, statisticians, physicists, and other researchers worked to develop a comprehensive terminology to serve as a foundation for quantitative imaging biomarker claims. Where possible, this working group adapted existing definitions derived from national or international standards bodies rather than invent new definitions for these terms.

US FDA and personalized medicine: in vitro diagnostic regulatory perspective.

Personalized medicine has captured the attention of the public, including patients, healthcare providers, scientists, medical product manufacturers and many others. The US FDA will evaluate many of the products that will allow personalized medicine to be successfully implemented in the USA. This article addresses the FDA's approach to regulation of one component of personalized medicine, in vitro diagnostic devices.

Protein-based multiplex assays: mock presubmissions to the US Food and Drug Administration.

As a part of ongoing efforts of the NCI-FDA Interagency Oncology Task Force subcommittee on molecular diagnostics, members of the Clinical Proteomic Technology Assessment for Cancer program of the National Cancer Institute have submitted 2 protein-based multiplex assay descriptions to the Office of In Vitro Diagnostic Device Evaluation and Safety, US Food and Drug Administration. The objective was to evaluate the analytical measurement criteria and studies needed to validate protein-based multiplex assays. Each submission described a different protein-based platform: a multiplex immunoaffinity mass spectrometry platform for protein quantification, and an immunological array platform quantifying glycoprotein isoforms.

Comparing two medical tests when results of reference standard are unavailable for those negative via both tests.

In studies for comparing the diagnostic accuracy of two qualitative tests, very often the reference standard to confirm the disease status is not applied to all study subjects. We considered a situation when all subjects with a positive result by at least one of the tests had a verified disease status and none of the subjects with both tests negative results had a verification of disease status. In this paper, we discuss whether the information about the ratio of true positive rates and the ratio of false positive rates of two qualitative tests, T(New) and T(Old), is sufficient to draw a conclusion about effectiveness of the T(New).