Despite cutbacks by the Centers for Medicare & Medicaid Services (CMS) in reimbursement for certain imaging modalities, the molecular imaging market continues to expand into uncharted territory. In particular, PET/CT — primarily used in oncology — has the potential to impact neurology, specifically Alzheimer’s. Additionally, the market has seen a rise in SPECT/CT as older SPECT models are being upgraded to include the CT component.

SPECT-only utilization has been decreasing for the past few years, and reduced reimbursement can account for part of it, says Don Bogutski, founder of Diagnostix Plus, based in Teaneck, New Jersey. CMS is cutting back on certain reimbursements or certain testing by having doctors cut back on SPECT scans. The modalities that CMS has targeted may impact higher volume exams in particular, such as SPECT. “This affects molecular imaging, specifically SPECT, because the number of scans done compared to PET are much higher,” says Bogutski. “Combined, SPECT and SPECT/CT are used eight times more than PET/CT.”

Stricter exam guidelines
Of course, it isn’t only CMS. Appropriate Use Criteria (AUC) was put into place by the American Society of Nuclear Cardiology to help physicians decide which type of patients would benefit most from nuclear imaging and other cardiac tests. Since physicians have become more discriminating as to whom they apply these tests to, this limits the number of scans being performed.

Dr. Prem Soman, director of nuclear cardiology at the University of Pittsburgh Medical Center, immediate past chair of the ACC Cardiovascular Imaging Council and vice president of the American Society of Nuclear Cardiology, acknowledges that these guidelines may actually be beneficial for patients. “Appropriate Use Criteria are beneficial to patients since they ensure that test selection is appropriate [for the patient]. The benefits generally outweigh any risks. For example, the patient’s exposure to radiation,” says Soman. “Studies also show that test performance is optimal when patients are selected based on AUC, rather than not.”

In the past, according to Dr. Garima Sharma, nuclear cardiologist at Johns Hopkins Health System in Baltimore, patients who had received a stent in a heart artery would get a SPECT scan even though there were no displayed symptoms. Now, with the guidelines, this scan is considered inappropriate since it causes unnecessary radiation exposure and can lead to more tests in the future if the tests are false positives.

SPECT is used for regular risk stratification of patients with chest pain, but there has been evidence suggesting that cardiac CT is just as valid for these patients, says Sharma, and this can be one reason why fewer nuclear scans are being conducted. “Cardiac CT is a better modality. It takes approximately 15 minutes to conduct a scan, while a nuclear medicine test would take at least four hours,” she says.

Though the number of patients sent to radiologists is decreasing, SPECT/CT sales have remained healthy, since the systems cost around $500,000, the least expensive compared to other molecular imaging systems. PET/CT is priced at approximately $1 million or more, depending on the number of slices in the CT scanner, and PET/MR is the most expensive, at over $5 million.

Myocardial perfusion imaging, which looks at how well blood flows through heart muscles, has been affected because of reimbursement cuts from CMS. But even with this reduction, there is belief that the studies are needed and there is room for it to grow again, especially in the U.S., considering obesity and heart disease are on the rise. “Myocardial perfusion imaging will not disappear completely, but there will be more scrutiny in making sure the patients being imaged are the appropriate recipients,” says Collin Schaeffer, product marketing manager for SPECT and SPECT/CT at Siemens Healthcare.

Exciting ideas impacting PET applications
The IDEAS (Imaging Dementia-Evidence for Amyloid Scanning) study is underway to determine the clinical usefulness of diagnosing Alzheimer’s and other dementias by performing certain brain PET scans. In the scan, amyloid plaque lights up, enabling accurate detection of plaque, an insight that may prove vital in diagnosing and ultimately helping treat those with dementia.

Regis Monticeli, product marketing manager for PET/CT at Siemens Healthcare, believes this study may be a driving factor for the growth of PET/CT since it has the potential to make PET a key procedure in the diagnosis of dementia. “If the IDEAS study proves the value of PET/CT and PET imaging for patient outcomes, the reimbursement that doctors get will drive the increase in PET/CT procedures,” predicts Monticeli.

Since dementia is not usually evaluated and assessed until symptoms are present, the patient may already be in the midst of the disease, but there is hope among physicians that it can be detected before symptoms show up. “If this is the case, then we should be able to identify these ‘high-risk’ individuals, image them and then provide therapeutics that slow or halt the progress of the disease,” says Wayne Webster, founder of Proactics Consulting in Melrose, Massachusetts. Radiologists seem to agree on the value that PET/CT brings to molecular imaging, especially with the prevalence of cancer, dementia and cardiac diseases.

“Physicians have begun to see PET/CT technology as more than just a scanner, but as a solution to help integrate quality, quantification and analytics into one machine,” says Kirill Shalyaev, Ph.D., vice president and general manager for advanced molecular imaging at Philips.

Defining the value of PET/MR
PET/MR has been used as a research tool for approximately five years, but cost and a limited body of guidance to recommend it have hampered its adoption. When PET first came onto the market, CMS insisted on very good research data proving the value of PET, says Jason Launders, director of operations of the health devices group at ECRI Institute in Plymouth Meeting, Pennsylvania. “PET registries were developed and doctors and hospitals were reimbursed to provide the studies as long as [doctors] provided the information of the patient studies to these registries,” says Launders. “They were able to build up good evidence supporting the use of PET, though it took a long time.”
For PET/MR, Launders believes that it will be a difficult process for researchers to prove that patients need this procedure, so to prove the value of PET/MR, multi-center trials will be required. Also, insurance companies will demand strong evidence from well-designed clinical trials. In addition to the cost of the equipment, another factor impeding the adoption of PET/MR is the maintenance. “You will need someone who is an expert with MR equipment, along with a nuclear physician, so adoption could be more difficult since more expertise is needed,” says Shalyaev.

Manufacturers talk about the advantage of PET/MR since a physician can acquire anatomical and physiological information of the same piece of tissue, at exactly the same time, says Launders. The image commonly produced is one combined image, with the PET image showing up in color over a grayscale MR image of the same anatomical region of the body. Ioannis Panagiotelis, Ph.D., and chief marketing officer of MR at GE Healthcare, believes PET/MR could be the platform to expand molecular imaging into the vast field of neuroscience, though some are not as hopeful.

“As long as the capital cost and operational cost of the system are high, I don’t think PET/MR will be commonly used in clinical settings,” says Mani Adib, senior project officer for the health devices group at ECRI Institute.

From analog to digital
Most radiologists are moving toward dual head cameras, but for facilities that continue to utilize single-head gamma cameras, there is a growing demand for cadmium zinc telluride (CZT), a solid state detector. These new detectors for gamma cameras are highly sensitive with a primary advantage of having a small footprint with few or no moving parts.

With a standard radiotracer dosage, one could acquire a full study in two minutes, according to UPMC’s Soman, and generally, with the new cameras, most labs are able to reduce acquisition time and tracer dose without compromising image quality or information. “As people are replacing their old cameras, they’re trending more and more toward CZT, and that’s a tremendous growth in the field,” says Soman. He adds that stress imaging, used to diagnose coronary heart disease, can be performed with 5 millicurie (mCi) with a highsensitivity camera, while with sodium iodide, an analog detector, the range is from 24 to 32 mCi.

With the advancements of CZT, scan time can be lowered to three minutes on certain cardiac systems, when it used to take 12 to 15 minutes, according to Nathan Hermony, general manager of nuclear medicine at GE Healthcare. GE has developed a resolution recovery on its system that can cut the scan times in half, so patients do not have to lie still for any longer than necessary. “The recent convergence of digital technology, enabled by CZT, and software development position nuclear medicine for growth and expansion,” says Panagiotelis.

Latest in the market
Since arriving on the market, additional advancements have enhanced the capabilities of PET/CT. “[Manufacturers] want to push the limits of PET/CT a little bit further, and we can already see this now, with the higher resolution PET and being able to pinpoint a disease process much more accurately,” says ECRI’s Launders.

In January, Siemens announced the arrival of the Biograph Horizon, an FDAapproved PET/CT that reduces capital and operational expenses by making it more
energy-efficient without compromising image quality, says Monticeli. Also, since the system has a small footprint, physicians who are looking to replace their current scanner may be able to fit it into their existing exam room.

The system helps providers address clinical applications in oncology, neurology and cardiology, and has automated manual tasks and offers protocol-based exams. One of the features, the Quanti•QC, can run quality control procedures overnight. Scans can be performed in five minutes and radiologists can acquire an image in 30 seconds.

Philips’ Vereos digital PET/CT gives physicians the opportunity to manage dose, reduce scan times and enhance lesion detection, and is also the first PET/CT system in the industry to use digital silicon photomultiplier detectors instead of traditional analog detectors, which results in an increase in quantitative accuracy compared to analog systems.

The Discovery IQ PET/CT by GE is designed to provide accurate quantitation with high image quality for small lesion detection, fast and efficient readings and a confident diagnosis by the physician. The Q.Clear technology that is part of the Discovery IQ offers no trade-off between image quality and quantitative standardized uptake value (SUV) measurements.

Potential new hybrid systems
New hybrid combinations such as optical/PET and optical/SPECT, along with X-ray/MR and optical/MR are being explored, and the ideas have been primarily presented at scientific talks, says Yossi Srour, president and CEO of UltraSPECT, based in Ra’anana, Israel.

According to the National Institute of Biomedical Imaging and Bioengineering, optical imaging, a noninvasive technique to look inside the body, uses visible light and special properties of photons to obtain detailed images of organs and tissues as well as cells and molecules. Quantitative measuring by SPECT or PET is not limited by tissue depth, according to research published by Joseph Culver in the Journal of Nuclear Medicine, and by combining either modality with planar optical imaging, the optical contrast data can provide high-throughput imaging of molecular and functional events, and nuclear imaging can provide the quantitative data.

Srour predicts the reading on hybrid systems will be done on the same reading system connected to PACS and hospital information systems, and all add-on software, workstations, visualization systems and CAD systems will be integrated into one huge server/cloud.