ACC: 1-second CT, mini ultrasound will dominate imaging in 2020
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Jagat Narula, MD, chief of cardiology at University of California, Irvine, opened the session, explaining that imaging is mimicking Moore’s law, which states that computer processing capability doubles every two years. Imaging also has embraced miniaturization, evidenced by ultrasound systems in the sub-five pound range, a hefty reduction from the original echocardiography systems, which weighed in at more than 400 pounds.
Narula offered a few directions for the future, opining that cardiovascular imaging needs to move toward the identification of pathology as a functional change, combine imaging and drug delivery, employ a personalized approach to dictate timely interventions and focus on evidence of the impact of imaging on outcomes.
Handheld ultrasound: The new stethoscope
Ultrasound has entered a new era and will replace the stethoscope by 2020, predicted Kirk Spencer, MD, of the University of Chicago. Spencer categorized ultrasound systems into four categories: full platforms, small systems weighing 20 to 30 pounds, hand-carried devices weighing five to eight pounds and pocket devices weighing less than two pounds. He clarified that his predictions related to pocket devices.
Handheld and pocket systems lose functionality, transducers and some features and capabilities. “However, there is no question that these devices can produce clinically useful images,” Spencer stated.
“The stethoscope has not seen much technical advancement in the 200 years since its invention. It is a primitive solution. Handheld ultrasound is a solution,” suggested Spencer.
Ultrasound offers significant gains over the physical examination. Spencer referred to research suggesting that hand-carried systems cut the miss and misidentification rates among cardiologists, provide incremental value to internists and increase medical students’ correct diagnoses when compared with the physical exam. Moreover, the devices have demonstrated adequacy for assessing left ventricular systolic dysfunction in the hands of experienced cardiologists and sonographers.
“Handheld and pocket ultrasound devices provide clinically useful images and can be readily used at the bedside. They will become a component of the cardiovascular care paradigm,” stated Spencer.
The expanding role of MRI in EP
In 2020, MRI will guide most electrophysiology procedures, predicted Henry R. Halperin, MD, of Johns Hopkins University School of Medicine in Baltimore.
Although ablation can cure many arrhythmias, the current recurrence rate is more than 30 percent, shared Halperin.
“We need improved imaging. 3D reconstruction is the current state of the art, but [even with advanced visualization] we don’t know if we actually ablated anything,” he said.
“Real-time, MRI-guided ablation could improve the paradigm by allowing physicians to visualize the scar directly and view lesions to see what has been ablated and offering enhanced visualization with gadolinium.” In addition, thermography could allow real-time catheter tracking, and image analysis and computation models may predict optimal targets, according to Halperin.
CT as the first line heart disease test
Cardiac CT angiography, which has seen its fair share of scrutiny, will benefit from “good evidence showing its clinical value by 2020,” predicted Suhny Abbara, MD, of Massachusetts General Hospital in Boston.
Abbara looked forward to other improvements, including continued reductions in dose to the point at which cardiac CT may be on par with a chest x-ray and improved temporal resolution, enabling the study to rival catheterization, MRI and echocardiography.
He also shared a few works in progress, noting that photon counting CT will be available in two to three years. In addition, DARPA has funded the Advanced X-ray Integrated Source (AXIS) project, aimed at the development of laser x-rays, 1,000 times more sensitive than current technology for imaging soft tissues.
The sum impact of these developments, said Abbara, is that cardiac CT will be employed in many applications beyond the coronary arteries.
SPECT/PET and disease management
“SPECT/PET will guide management of the stable ischemic heart disease patient,” stated Daniel S. Berman, MD, director of cardiac imaging at Cedars-Sinai Heart Institute in Los Angeles.
Looking into the crystal ball, Berman noted that cardiologists will see an uptick in the numbers of patients in heart and renal failure due to the aging population. Consequently, they need imaging data to inform disease management.
PET and SPECT imaging could provide essential data. A new radiopharmaceutical entering phase 3 trials provides improved uptake to enable more effective characterization of coronary perfusion, shared Berman. He continued, “I-123 MIBG imaging to predict the need for ICD will hopefully be approved soon.”
Ultimately, cardiologists will be able to measure absolute blood flow with PET and even SPECT, he added.
Berman continued, predicting that in the next decade cardiologists may be employing molecular imaging to define a new disease entity--microvascular disease--that may not be apparent by standard anatomic imaging methods. And automatic quantitative analysis of SPECT/PET will become routine, predicted Berman.
Other developments also are proceeding as new SPECT cameras deliver improved resolution and decreased radiation.
Although Berman foresees increasing utilization of hybrid devices, he noted that nuclear studies fill a gap that anatomic imaging does not. Specifically, nuclear imaging offers the ability to predict therapeutic benefit based on the amount of ischemia. In fact, he predicted that the ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches) trial, a six year, multi-center trial, will demonstrate the predictive benefit of PET/SPECT imaging.
SPECT and PET will enjoy an excellent future, summarized Berman.