SPECT Suits Up with Speed and Sensitivity
Siemens TruePoint SPECT/CT from the Symbia product family includes multidetector CT configurations with speeds of up to 0.6 seconds per rotation.

Single photon emission computed tomography (SPECT) has proven itself over time in imaging patients with suspected or confirmed coronary artery disease. Not only has it stood up to several new technologies, the list of indications for SPECT is growing. Greater speed and relatively low costs are just what the healthcare industry needs.

‘Better at a better price’

Since SPECT first came on the scene in the 1970s, there have been dramatic changes. Originally, SPECT scanning did not involve rotating around the heart, speeds have been cut by about one quarter and, even with vast technological improvements, the costs have gone down. “We also added ventricular function,” says Gary Heller, MD, PhD, director of Nuclear Cardiology at Hartford Hospital in Hartford, Conn., and director of the Cardiovascular Fellowship Program and professor of Medicine and Nuclear Medicine at the University of Connecticut School of Medicine. Heller’s facility uses CardioMD and Cardio 60 from Philips Medical Systems.

“The technology continues to evolve,” he says. “The cameras are more sophisticated, but cheaper. We’re better at a better price. Even though the technology is older, it still provides considerable benefit to patients.” Heller does about 6,000 SPECT studies a year.

From time to time, something else is touted as the next best thing that will replace cardiac SPECT scanning. “I’ve been hearing that since I started in the late 1990s,” says Chad Timisen, nuclear medicine manager for North Phoenix Heart Center in Arizona. “It never happens. When all is said and done, it’s usually still SPECT standing.” Timisen’s department uses a Ventri dual-head dedicated cardiac SPECT camera from GE Healthcare.

Heller agrees that SPECT has been a “mainstay of noninvasive imaging for patients with suspected coronary artery disease [CAD] or with [confirmed] CAD.”

Standing up to competition

SPECT continues to rate well when compared with other, newer technologies, Heller says. For example, “stress echo tells you function at peak stress, but doesn’t tell you anything about perfusion.”

Cardiac catheterization generally requires an overnight hospital stay or same-day admission. SPECT can be performed in a physician’s office and costs much less. A good SPECT camera costs about $250,000, compared with a $1.5 million price tag for a CT scanner, Heller says.

When you consider the cost of SPECT equipment, a physician practice can actually acquire the equipment and run a lab at a much lower financial risk, says Timisen. Plus, reimbursement for some PET/CT exams are still up for debate among payers, including Medicare. “I think that makes [SPECT] enticing for cardiologists, and for imaging centers,” he says. “You’d be hard-pressed to get people to pay out of pocket for testing that they could have covered through insurance.”

The use of SPECT eventually will decrease the overall cost of diagnosing and treating CAD, says Harry Lessig, MD, FACNP, FACNM, co-director of nuclear medicine at Deborah Heart and Lung Center in Brown Mills, N.J. He already has used single and dual-head SPECT equipment from Siemens Medical Solutions. The Symbia T, a TruePoint SPECT/CT system that combines a dual-detector variable angle gamma camera with a CT scanner, will be installed in September. Eighty percent of the SPECT work done at Deborah is within nuclear cardiology.

“SPECT will determine those patients who do not need cardiac catheterization,” he says. Some believe magnetic resonance imaging “is the wave of the future. The problem with that is it is extraordinarily expensive and will probably overdiagnose certain things,” he says. Cardiologists are in the process of working out when and how SPECT should be used. “We need to collaborate on the best procedures for conditions in the next two to five years. When we learn what modalities to use for what, we’ll have savings.”

SPECT’s surprising sensitivity

Aside from cost savings, SPECT offers unique levels of sensitivity and specificity. Timisen points out that the physiological aspect of nuclear medicine can show problems other modalities cannot. He says a lot of his patients have normal stress test results and no chest pain or other symptoms, but “when we do the images, the [patient has] a blockage. The patient doesn’t feel it at all.”

Cardiospecialists Group Ltd., with three clinics in the Chicago area, recently upgraded to its third SPECT camera from Digirad, says Robert Litchfield, DO. He says he didn’t go into oncology because he didn’t want to have to tell patients they had cancer, but the SPECT camera’s sensitivity has brought Litchfield closer to cancer than he ever planned. Soon after his first purchase, the Cardius XPO, Litchfield tested a healthy man whose pulse oximetry number dropped. “I thought it was wrong,” he says. “The scan showed that the heart had a problem, but there was uptake in the lung. I didn’t know what it was.” A lung CT showed that the man had cancer. Another similar experience led Litchfield to track the next 1,000 patients to determine what, besides heart problems, he could detect. The Digirad camera had 82 findings; another camera found nothing in the same cases. About half of the 82 findings came back as serious problems, mostly cancers.

“It was clear to me that this is a very sensitive thing,” he says. He presented his findings at a Society of Nuclear Medicine meeting to some incredulous participants. Demand led Cardiospecialists to upgrade to the Cardius 2MXPO, a dual-head camera and go from six patients a day to 11. The group recently tried out Digirad’s triple-head camera and new software for a month. With that equipment, Litchfield was able to reduce imaging time from 20 to 30 minutes down to just 4 to 7 minutes. Plus, patients can be imaged while sitting up in a chair.

More to come

Time is of the essence as demand increases. Timisen and the other technologists at his organization can perform SPECT imaging on 16 patients in a busy eight-hour shift. He points out that they can manage that volume because all the procedures are filtered through a nurse practitioner. Other practices might have each physician ordering procedures along with different set-up which results in significant down time. “To keep that throughput on the camera, you have to have all aspects of your lab on the same page,” he says. “It’s like running a conveyor belt.”

Another draw for Litchfield to the Cardius was that he didn’t have to tear down a wall to install it. In fact, it is mobile plug-and-play equipment—“any plug, which is wild.” Litchfield saw the equipment demonstrated after it had sat on a truck in below-zero temperatures all night. “We started using it right away” with no problems. He was sold after comparing images from the Cardius to the competition.

SPECT “has had a huge blossom in the last 5 to 8 years,” says Litchfield. “I think it’s only going to increase.” Faster CT scans will allow for calcium scoring of the heart. Usually, SPECT imaging is performed once MR angiography has proven that arterial narrowing is hemodynamically significant. “Those two things alone should increase usage,” he says. SPECT can prevent unneeded testing. If a stress nuclear study comes back normal, the risk of heart attack in that patient over the next two years in less than 1 percent. If results are abnormal, the risk is 8 to 40 percent. That can help clinicians limit more invasive testing to those that really need it.

Litchfield also sees a place for SPECT in medical management. For example, many people with diabetes lose the ability to feel chest pain after a certain age. “The warning mechanism doesn’t work,” so they should undergo SPECT imaging every two years” to check for heart problems.

The list goes on and on, Litchfield says, for other conditions that could benefit from SPECT. And, research on the validity of various modalities has shown that SPECT imaging had much higher sensitivity and specificity than the others. “It really is the test to do.”