The first new Revolution CT scanner for WA Health was installed at Royal Perth Hospital in December 2016, with three more of GE’s latest, top-of-the-line computed tomography scanners going into service for Western Australia’s public health system this year. “We haven’t had it for long, but the advantages that this scanner brings to the table have already expanded our horizons a lot,” says consultant cardiologist Dr Arun Abraham.
It’s 40 years since GE brought the first CT scanner to Australia, with the debut CT installed in Sutherland, NSW, in 1977, only a year after they were commercially released in the US. Back then, it was hailed as breakthrough technology and the advances made in subsequent decades are universally acknowledged as having transformed medicine.
GE Healthcare has a simple line to tout its top scanner’s tech: it makes advanced exams routine, and routine exams advanced. The Revolution CT combines in one system high coverage, spatial and temporal resolution and spectral imaging. The included Smart Technologies software suite includes a range of tools to help radiologists get the most out of the scanner, including with complex cases, such as stroke and cardiac patients, always prioritising the lowest possible radiation doses and high image quality.
A second Revolution CT is operating at RPH, in the emergency department, and WA Health’s final two new Revolution CTs will be installed at Sir Charles Gairdner, where the CT will specialise in neurological scans, and Rockingham General Hospital, south of Perth.
Four imaging specialists at Royal Perth Hospital made time to talk with GE Reports about the hospital’s new CT scanner. Dr Abraham and specialist thoracic imaging and interventional radiologist Dr Kay-Vin Lam, along with RPH’s chief CT specialist Melanie Rosenberg and Chief Medical Imaging Technologist Helen Parry explained how the Revolution CT scanner is revolutionising their clinical practice and improving outcomes for public patients in Perth and beyond.
Radiologists can lower the radiation dose, and still get rich imaging
Dr Kay-Vin Lam: “We are scanning at low dose and still getting excellent image quality. Low dose is important for everyone. It’s cumulative, so you want to go as low as you can, and now I can do it sometimes at 1% of the dose that I’ve used previously. Especially for young patients—anyone under 50—this is really important. Now, I can do what we call an ultra-low dose CT chest scan, and it’s equivalent to the radiation exposure of a chest X-ray, and gives me probably a 50-times information increase. One of the biggest deals in this department is making the most of our CT scanners and getting the dose as low as possible for our patients.”
Cardiologists love the Revolution CT
Dr Arun Abraham: “Cardiac CT has always been probably the most challenging aspect of implementing CT technology because you’ve got to do things fast and you’ve got to do things in a moving organ. This scanner has essentially taken away a lot of question marks. It hasn’t changed what we do, but it’s made the whole thing a lot easier. On this machine, all the usual constraints that we had—patients having irregular heartbeats, irregular heart rhythms, difficulties with patients not able to do a prolonged breath hold—have essentially disappeared. Scanning a moving organ has become significantly easier with the Revolution CT because of two things: it rotates fast, but so do many other scanners, and also it’s got very good volume coverage. Then you’ve got the added security of GE proprietary technology, called SnapShot Freeze, built into the scanner. It allows us to correct for coronary motion after the fact, if we need to. So in addition to physics-related superiority at the time of scanning, we have the ability to enhance the image after the scan, which we use very seldom because we pay good attention to other parts of the process, but when we need it, we know it’s available. It’s a related concept to a camera’s post-focus function, and looks for motion before and after the image, and intelligently adapts to motion limited to coronary arteries. This machine’s got very robust automatic scanning capabilities. There’s been no technology that I know of in cardiology—that’s my area of expertise, I can’t speak for the rest—that has improved to this degree in the past decade and a half.”
Precision scans for fast stroke intervention
Melanie Rosenberg: “The perfusion scans we can do now are another of the clinical areas where the new CT is changing things for us, especially with stroke protocols. With stroke patients, there is a three- to six-hour window where neuro-interventionists have the opportunity to remove the clot and restore circulation. We can do a perfusion scan and show them the exact area of the brain that’s been affected, and how much tissue is at risk of dying if circulation is not restored. The perfusion scan is easy to set up and perform, can cover almost the whole brain and provides vital information for treatment choices. The software used to process the perfusion data is so streamlined and easy to use. The perfusion images provide definitive results for the Neurointerventional Radiologist when deciding to remove clots. Clot retrieval is cutting edge and we have had some remarkable results.”
Room to move—and fast
Melanie Rosenberg: “I really like the size of the gantry [the donut hole of the CT that the patient slides into for their scan]. This is the widest one around; it’s 80cm in diameter. This size of the gantry and the increase in weight limit allows us to scan patients of all shapes and sizes. It is easier to offset patients to scan extremities and we have had a lot fewer incidences of claustrophobia.
“We had to do a full trauma CT in here not long ago; the poor gentleman had fallen about 10 metres. One of the features of this scanner is that the table can move 1800mm in a helical mode, which meant that we could position him on the table and not have to keep moving him up and down the table to scan different regions. This certainly increases the speed of the examination which is crucial with trauma patients. The other advantage of a long table movement is being able to scan more body regions in one scan and using one bolus of contrast. This patient had his chest, abdomen and legs scanned with a single contrast injection. This one scan provided information on his chest, abdomen, pelvic bones, spine, blood supply to his legs, and his fractured knee, femur and ankle.
“In the Emergency setting, one of the hardest patient presentations to evaluate is chest pain. It’s life threatening and has three main causes: dissecting arteries, myocardial infarction and pulmonary embolisms. In the past, we have been unable to accurately rule these out in one scan, however with Revolution CT we can accurately visualise all three pathologies in the one scan. The chest can be imaged in two heart beats and the abdominal scan follows straight on. The ‘Auto Gating’ features ensure that all CT Radiographers are able to produce optimal images. This scan rules out the need for other tests, which means patients are treated quickly.”
Dr Arun Abraham: “In the past it was inconceivable to do a CT scan on a patient who is ventilated and in ICU. And when somebody comes into the scanner, the amount of time that they spend in the scanner’s less. It was an average of 25-30 minutes in the past, now it’s more like 15 minutes. It also means that cardiac scanning is less stressful and challenging for people—both the medical personnel and patients.”
The things you will see…
Dr Kay-Vin Lam: “There are some things that we haven’t started experimenting with on this new scanner which will give us more information than we’ve ever been able to get before. There have been trials in Japan on older CT scanners where they looked at lung cancers, for example. When you look at a lung cancer, you can see how much contrast [dye] goes through the body of the cancer, but also the lymph nodes inside. And it can suggest to us which lymph nodes may be cancerous and which may be normal. With this new scanner, we believe there is great potential to give us better imaging, and more specific answers than what clinicians have been using PET scans for. So more information, more accuracy potentially, and at far lower radiation. That’s the sort of thing we’re hoping to be able to do.”
The scanner places the radiation shields virtually
Melanie Rosenberg: “The Revolution CT’s dose modulation is very effective, and has many facets which has helped us significantly reduce the doses. We have always used eye shields, breast shields and thyroid shields during scanning, which is costly. Now, the shields are actually incorporated into the scanning. It’s called Organ Dose Modulation. We are able to select which organs to protect and adjust it for each patient. It appears as a pink band on our planning scans, which makes it hard to miss. It’s clever.”
Technology that will go the distance
Helen Parry: “In the public health system, most of our equipment gets turned over about every 10 years, so that’s quite a long time. For example, how’s your 10-year-old laptop going? Not so well. Upgrade paths have to be a feature of any type of equipment that we’re buying at Royal Perth Hospital. We got in on the ground floor with the Revolution CT, because it’s the latest technology. Given that we will have this scanner for eight to 10 years, we have every confidence that, with the software upgrades along the way, and the fact that this is state-of-the-art now, that it’ll remain up to date for that time.”