Radiologists and Clinical Trials: Part 2: Practical Statistical Methods for Understanding and Monitoring Independent Reader Performance.

Though many clinical trials rely on medical image evaluations for primary or key secondary endpoints, the methods to monitor reader performance are all too often mired in the legacy use of adjudication rates. If misused, this simple metric can be misleading and sometimes entirely contradictory. Furthermore, attempts to overcome the limitations of adjudication rates using de novo or ad hoc methods often ignore well-established research conducted over the last half-century and can lead to inaccurate conclusions or variable interpretations.

Radiologists and Clinical Trials: Part 1 The Truth About Reader Disagreements.

The debate over human visual perception and how medical images should be interpreted have persisted since X-rays were the only imaging technique available. Concerns over rates of disagreement between expert image readers are associated with much of the clinical research and at times driven by the belief that any image endpoint variability is problematic. The deeper understanding of the reasons, value, and risk of disagreement are somewhat siloed, leading, at times, to costly and risky approaches, especially in clinical trials.

US FDA draft Guidance Standard for Clinical Trial Imaging Endpoints: more than just imaging?

The current cost of developing a successful drug is typically over a billion dollars, with the registration trial(s) determining the success or failure of the entire development program. Often the primary endpoint of these trials is a subjective assessment. For registration trials with subjective endpoints, a regulatory agency may require a blinded independent central review (BICR) of the trial data.

Detection of coronary artery disease with perfusion stress echocardiography using a novel ultrasound imaging agent: two Phase 3 international trials in comparison with radionuclide perfusion imaging.

Aims: To determine if perfusion stress echocardiography (PSE) with Imagify (perflubutane polymer microspheres) is comparable to stress perfusion imaging using (99m)Tc single photon emission computed tomography (SPECT) for coronary artery disease (CAD) detection. PSE is a novel technique for evaluating myocardial perfusion. RAMP (real-time assessment of myocardial perfusion)-1 and -2 were international, Phase 3 trials that evaluated the ability of PSE with Imagify, to detect CAD.

Phase I and pharmacokinetic study of AI-850, a novel microparticle hydrophobic drug delivery system for paclitaxel.

Purpose: AI-850, paclitaxel in a novel polyoxyethylated castor oil-free hydrophobic microparticle delivery system, is being developed based on its favorable preclinical safety and antitumor activity profiles. The objectives of the study were to assess the feasibility and safety of administering AI-850 as a <30-min i.v.

Measurement of radial artery contrast intensity to assess cardiac microbubble behavior.

Objectives: We sought to determine whether analysis of the contrast signal from the radial artery is better able to reflect changes in left ventricular (LV) microbubble dynamics than the signal from the LV itself.

Background: Assessment of microbubble behavior from images of the LV may be affected by attenuation from overlying microbubbles and nonuniform background signal intensities. The signal intensity from contrast in a peripheral artery is not affected by these artifacts and may, thus, be more accurate.

The effect of a phosphodiester linking group on albumin binding, blood half-life, and relaxivity of intravascular diethylenetriaminepentaacetato aquo gadolinium(III) MRI contrast agents.

Amphiphilic gadolinium complexes were investigated as potential magnetic resonance imaging (MRI) contrast agents. A series of complexes was synthesized in order to study the effect of hydrophilic phosphodiester groups on albumin binding, relaxivity, and blood half-life in rats. Thus, compound 11a, a diethylenetriaminepentaacetato aquo gadolinium(III) (Gd-DTPA) derivative with an octyl substituent, was synthesized and compared to 5b, the analogous octyl derivative containing a phosphodiester linkage between the gadolinium chelate and the alkyl chain.

Evaluation of a new ultrasound contrast agent (AI-700) using two-dimensional and three-dimensional imaging during acute ischemia.

Background: A new intravenous contrast agent, AI-700, was evaluated to determine whether a bolus injection could be used to detect myocardial perfusion abnormalities during acute ischemia by using 2-dimensional (2D) and 3-dimensional (3D) myocardial contrast echocardiography.

Methods: 2D MCE was performed in 14 closed-chest dogs during coronary occlusion by using both continuous and triggered gray scale harmonic imaging and triggered power Doppler imaging. 3D MCE (open-chest) and nuclear perfusion imaging were performed in 10 of the 14 dogs.