By Nick Klenske
Clinical trials have long been the gold standard for evaluating and optimizing the design and clinical use of medical imaging devices and methods. Unfortunately, these trials tend to be expensive, time-consuming, and require a large patient cohort. They might also carry some risks, such as when the trials require the use of ionizing radiation.
“Add to this the increasing complexity and sheer diversity of available medical imaging technologies, and it’s clear to see why the clinical trial has lost some of its luster,” said Ehsan Samei, PhD, director and principal investigator at Duke University’s Center for Virtual Imaging Trials.
Speaking at a Sunday session, Dr. Samei explained why virtual imaging trials (VITs) have emerged as an effective new approach for assessing the latest in medical imaging innovation.
According to Dr. Samei, medical imaging practice and trials can be done computationally using so-called virtual or in silico models of patients, imaging systems, and the image interpretation process. Depending on the imaging task to be assessed, each component will include various models to be simulated.
“Virtual imaging trials are based on the simulation of human anatomy, imaging modalities and image interpretation, which parallel the components of real-life imaging trials,” he said.
Because the imaging modalities are simulated based on the physical principles used to generate images from human anatomy, the simulation must be highly detailed and realistic for the task in question. For instance, the nuanced imaging signatures of the disease, the spatial and temporal resolution of the imaging system, and the qualification of the analyzed image descriptors should include the details needed to perform the required detection or quantification task.
This point touches on one of VITs priorities: ensuring that patient models, particularly digital twins of the patients, are realistic representations of real patients and that the simulation pipeline offers the appropriate level of detail.
“To ensure that the clinical scenario can be repeated and that our answers are reliable and relevant, VIT requires realistic digital twins of the patient’s anatomy and physiology and of the diagnostic and therapeutic methodologies being used,” Dr. Samei said.
Dr. Samei is quick to note that he believes VIT’s potential benefits outweigh its challenges. To illustrate, he discussed how the effective use of imaging systems requires repeated cycles in which various combinations of system parameters need to be tested and optimized–something that is rarely practical within the confines of the clinical trial.
“Repeating patient images for each parameter combination is prohibitive, both on ethical and financial grounds,” he said. “Even if one attempts to do so, it will take a long time–totally out of step with the immediacy and the multiplicity of the need.”
VITs, on the other hand, offer the flexibility to vary the characteristics of virtual patients and can be repeated as many times as needed, for the cost of computer time only.
“With the potential to accelerate the development of medical imaging systems, not to mention help bring novel imaging methods to patients quicker and at a lower cost, radiology would be remiss not to take full advantage of virtual imaging trials,” Dr. Samei concluded.
Access the presentation, “VCT and Its Role in Radiology,” (S2-CPH03B) on demand at RSNA.org/MeetingCentral.
© 2024 RSNA.
The RSNA 2024 Daily Bulletin is the official publication of the 110th Scientific Assembly and Annual Meeting of the Radiological Society of North America. Published online Sunday, December 1 — Friday, December 6.
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