Innovation spotlight: Advancing Cardiac Computed Tomography (CT) Imaging

Over the last 20 years, treatments have advanced tremendously but so has the imaging technology that works so critically alongside it. Here, Mani Vembar, Principal Scientist, CT Clinical Science, shares how Philips has been at the forefront of this important work and the added value that imaging now brings to cardiovascular care. 

The early years: from promise to practice

In the early days of cardiac CT, slow speeds, limited anatomical coverage, and radiation dose concerns were fundamental limitations to reliably achieving diagnostic-quality scans. While other organs are somewhat stationary, the heart is constantly in a dynamic state, pumping blood through small, rapidly moving coronary arteries.

Advancements in imaging technology over the past two decades have addressed these limitations, significantly improving cardiac CT performance. There are many cardiac diseases that can be detected by CT, but the guidelines are specific for coronary artery disease (CAD). For example, the American College of Cardiology (ACC) and European Society of Cardiology (ESC) recommend cardiac CT as the first-line test when it comes to ruling out CAD [2] [3]. 

The slice wars, the dose wars

Anatomical coverage is important in cardiac CT and is commonly quantified as the number of ‘slices.’ Each increase in slice count translates directly into expanded coverage, reduced scan times, and improved success rates. In response, Philips progressed CT technology with its groundbreaking NanoPanel modular detector. This enabled rapid and continuous image quality improvements and increasingly larger coverage – and most importantly, expanding the population of patients who could benefit from cardiac CT.

However, dose challenges remained. With Step & Shoot Cardiac, Philips reduced radiation exposure by 80% [4] by using electrocardiograph (ECG) signals to limit x-ray exposure to a single moment within each heartbeat – unlike traditional gated helical scans, which expose patients to higher radiation levels by capturing images throughout the cardiac cycle.

Philips continued to further reduce radiation dose throughout the imaging chain: iDose⁴, an innovative reconstruction algorithm, improved image quality by increasing resolution, lowering noise and preventing artifacts [5], while knowledge-based iterative model reconstruction (IMR) pushed this even further to deliver clear images at extraordinarily low radiation doses [6].

A brilliant leap for cardiac care 

Philips continued to navigate the technical complexity of cardiac CT with sophisticated algorithms, including adaptive multi-cycle reconstruction that optimized temporal resolution and beat-to-beat variable delay algorithms that captured consistent cardiac phases, even as heart rates varied during scans [7] [8].

The introduction of Philips' Brilliance iCT marked a watershed moment in what cardiac CT could achieve. With a detector that could encompass the entire heart in just two acquisitions, the result enabled faster scans, higher success rates and significantly better image quality over a wider range of heart rates – with up to 80% dose reduction [9]. This was the entry point for cardiac CT as a mainstream clinical tool.

Spectral CT: the next frontier 

By the mid-2010s, conventional cardiac CT challenges were largely solved. Philips then further advanced the field with detector-based spectral CT technology that simultaneously captured both high- and low-energy photon information in one scan – without additional dose, time, or workflow impact [10].

Spectral CT had a huge impact: reducing blooming in calcified plaques, optimizing visualization while reducing contrast agent doses, assessing myocardial perfusion [11], and improving evaluation around metallic coronary stents – truly providing a "one-stop shop" for comprehensive cardiac assessment [12] [13] [14].

Making cardiac CT smart 

Incorporating the latest software solutions with hardware/technology is vital to meet the further increase in demand for advanced imaging in cardiac CT. Philips' most recent cardiac imaging innovations have been in the field of image reconstruction. Precise Cardiac compensates for heart motion with intelligent algorithms to reduce motion artifacts [15]. Precise Image employs AI to simultaneously reduce noise, improve image quality, and enable lower radiation dose [16]. Advancements like these enable routine high-quality cardiac scans to be performed swiftly and with lower radiation doses, for wider cohorts of patients.

Leaps and bounds in cardiac innovation 

The role of technologic advancements remains vital to cardiac CT and when it comes to innovation, at Philips we are just getting started. Stay tuned as we continue to accelerate the transformation through AI-powered solutions, to enable a future of better cardiac care for more people.