Computed tomography (often called CT scan or CAT scan) revolutionized medicine when it was introduced in October 1971 50 years ago. Traditional X-rays—not even today.

Over the years, with the advancement of technology, CT scans have enabled doctors to observe the internal conditions of vital organs and blood vessels such as the heart, brain, and arteries.

Now, CT scanning has taken another step forward, and researchers from the Medical University of South Carolina have participated in the process.

Siemens Healthineers will officially launch its NAEOTOM Alpha photon counting CT system at a virtual event on November 18, but as part of the landmark project of the MUSC and Siemens strategic value partnership, MUSC researchers and technicians have been working since July Use of new equipment. MUSC and Siemens Healthineers have a decades-long partnership. In 2018, the two entities announced a strategic partnership aimed at changing the way healthcare is provided. This relationship has been further consolidated.

So far, the photon counting CT system has only been used for research, but with the recent approval of the new technology by the Food and Drug Administration, it will soon be used for patient care.

"This is an exciting time for MUSC." said U. Joseph Schoepf, MD, director of the Department of Cardiovascular Imaging and Assistant Dean of Clinical Research at MUSC School of Medicine.

Siemens Healthineers said that this is not just an update of existing technology. This is a new method of detecting the photons that make up X-rays.

Traditional CT scanners use X-rays, but instead of scanning the body from one side, the scanner rotates around the patient's body and sends X-rays as the patient moves. Computer algorithms combine the results into images, allowing radiologists to see "slices" of the body, like slices of a loaf of bread.

However, X-rays can only be registered and form images when they have a certain intensity and exceed a certain level.

Schoepf said that photon counting CT uses a new type of detector that enables it to record or "count" each photon to generate an image showing the full spectrum of photons.

Dr. Jim O'Doherty is a research scientist and R&D cooperation manager at Siemens Healthineers, based at MUSC full-time. He explained that each X-ray has its own energy.

"On the old scanner, we don't know what the energy is. On this new photon counting CT, we can now detect the energy of X-rays, which means we can make better images at each specific energy," He said.

Better images mean that doctors and patients have better information to make critical decisions.

Shepf says that radiologists can see how the tissue is composed. Moreover, because the scanner does not waste radiation on unreadable X-rays, it requires less radiation.

Schoepf and his team have been scanning patients in a study, comparing their images obtained using photon counting CT with conventional CT, to test whether the theory behind photon counting CT is valid in a real-world environment. So far, they have scanned about 70 patients, with a target of 130 patients.

Tilman Emrich, MD, MUSC Photon Counting CT Research Director, said that they have been able to demonstrate theoretical advantages, including clearer images, less radiation used on patients, and improvements to some of the limitations of existing CT scanners.

One of these shortcomings-what Schoepf calls the Achilles heel of CT-is coronary artery calcification imaging.

"Calcium looks much larger in CT images than in real life," he said.

This means that CT images are more likely to indicate narrowing or narrowing of arteries. Whenever a CT scan shows that there may be a stenosis, the patient is sent to the catheterization laboratory for additional examinations, which requires inserting a tube in the groin, using contrast media, and more radiation—not to mention the patient’s The additional anxiety and expense are.

"Better spatial resolution allows us to better read calcium, which means we send fewer patients to the cath lab unnecessarily," Schoepf said.

The reverse is also true-photon counting CT can detect irregularities that cannot be detected by conventional CT. Since Schoepf's team uses photon counting CT as part of the trial, the standard of care they provide to any volunteers is not lower than the current standard. However, they can provide additional care—for example, in one patient, photon counting CT showed a myocardial perfusion defect that was not visible on conventional CT. The patient was referred for additional MRI examinations.

As part of the research, information flows back and forth between Siemens Healthineers and MUSC to continuously improve the scanner. Anonymous data from MUSC allowed the engineering team to improve the reconstruction algorithm.

"We want them to make sure they are satisfied with the results when they post-process the scan," O'Doherty said. "We want to make sure that what the software does is actually scientifically correct-but also medically correct. So a lot of things are done back and forth between our German developers and the clinical team here; this is basically Above is my link."

The MUSC team is excited about what they have seen so far.

"The quality and clarity of the image we saw impressed us, but we knew it would go further," Emrich said.

People expect this scanner to improve the imaging of the heart. Akos Varga-Szemes, MD, Director of Cardiovascular Imaging Research at MUSC, describes it as the most difficult organ to image because it is always in motion. He said that as the resolution increases, it takes more time to generate data, which makes ultra-high resolution heart scans a technical challenge.

"If you want to imagine a hand, you can say,'Don't move your hand.' If you want to image the lungs, you can say, "Don't move and stop breathing for a second," and then we rush over . But for the heart, it keeps moving," he said.

Schoepf said the researchers are still studying whether the traditional two-scan protocol can be combined into a single scan to further reduce radiation exposure. Cardiac CT scans usually include one scan to capture calcifications, and a second scan to inject contrast dye to highlight blood vessels; photon counting CT can capture all this information during a single scan.

While the MUSC team is focusing on cardiac imaging, Siemens Healthineers is collaborating with other institutions around the world focusing on brain, chest and cancer scanning. Schoepf hopes that the scanner can improve images of various diseases, such as interstitial lung disease; surgery, such as tumor imaging before and after cancer treatment; and body parts, including the inner ear.

The radiology artificial intelligence program proved so useful that the technology will now be used throughout the MUSC health system.

The collaboration has brought digital advancements, new understandings and improvements in patient care.

MUSC and Siemens Healthineers announced an unprecedented transformation partnership in the history of MUSC.

Leslie Cantu MUSC Catalyst News

Keywords: innovation, heart story, research