For the 12 years prior to the installation of the new Alphenix system, we were using an Infinix-I INFX-8000V. However, all angiography systems will inevitably deteriorate over the course of time, and the failure rate will tend to also increase as a result.
Compared with the newer models housed in our other catheterization laboratories, the Infinix-i delivered much higher doses in radiography and fluorography examinations, putting it at a strong disadvantage overall. Therefore, we felt it was time to install a new system.
The new Alphenix system provides many benefits, including reduced exposure dose, advanced image processing capabilities, a user-friendly design, and significantly improved image quality.
In fact, one of our patients, who has been receiving care at the clinic since its establishment, has been examined with three different systems over the years: the Infinix system (1999), an Infinix-i system (2014), and the Alphenix system (2018).
Figure 1 shows images of this patient acquired with these three systems. The Alphenix image shows a much clearer contrast between structures, such as vascular margins. This is an excellent example of the higher resolution that can now be achieved thanks to Canon Medical’s technological advances.
Figure 1 Images of the same patient acquired using three successive systems at Toyohashi Heart Center
Alphenix new Stent Mode is clinically effective and 7.5-fps fluorography is free of image lag.
The Alphenix’s new Stent Mode is an effective tool suitable for routine clinical use. When we perform diagnostic catheterization procedures in patients with suspected stent fracture, the use of Stent Mode allows the stents to be clearly visualized, making it much easier to determine the presence or absence of stent fracture. The stent visualization enhancement functions in systems produced by other companies employ a marker for a fixed display of the stent, but this can interfere with visualization. Alphenix’s Stent Mode, on the other hand, permits the status of the stent to be confirmed easily in a conventional image. Clear images can be obtained even when the stent overlaps the diaphragm and is difficult to see.
We have, therefore, found the new Stent Mode to be very useful in our clinical practice.
Another benefit of Alphenix is its excellent image quality, even when fluorography is performed at low pulse rates. For example, this imaging method was found to be extremely effective in a patient with chronic total occlusion (CTO) of the left anterior descending artery (LAD). First, a guidewire was advanced under fluorographic guidance at 7.5 frames per second (fps).
Tip injection was then performed, and the catheter could be clearly depicted.
In addition, the large and rapid cardiac movements observed in right anterior oblique (RAO) and RAO caudal views often lead to image lag, which interferes with visualization of the guidewire, making it difficult to determine the direction the tip is facing and how it is moving. For vascular surgeons, this is one of the most frustrating limitations of angiography systems. The Alphenix system overcomes this limitation because it is virtually free of image lag, allowing the tip of the guidewire to be clearly visualized at all times. It can, therefore, be expected to improve the precision of such interventions, while shortening procedure times.
Minimizing exposure dose
Minimizing radiation exposure during fluorography is an important goal. In particular, when a time-consuming procedure is conducted in a left anterior oblique (LAO) caudal view (LAO 40°, caudal 30°; the so-called spider view), there is an increased risk of excessive X-ray exposure. For example, one patient who was treated at our institution developed severe radiodermatitis that required skin grafting. To avoid such adverse events in the future, the actual exposure dose was measured in each of our four catheterization laboratories, under the same conditions.
A 20-cm acrylic plate was placed at the examination position, and measurements were obtained while the fluorography and radiography programs were run on the four different systems, using the same parameters as in routine clinical practice. The dose measurements obtained for Alphenix were equal to or lower than those obtained from the other three systems. Compared to the Infinix system we had used previously, Alphenix showed dose reductions of approximately 60% and 50% in fluorography and radiography, respectively. This is truly a remarkable improvement. When the thickness of the acrylic plate was increased to simulate a larger patient, the dose during image acquisition was increased by a factor of three to seven in all the systems, but Alphenix was found to have the lowest dose.
Alphenix also provides a tool known as the Dose Tracking System (DTS), which measures and displays the patient estimated peak skin dose in real-time. This function makes it easy for the operator to identify ‘hot spots’ and take appropriate measures to avoid them as much as possible.
Furthermore, while DTS improves awareness of high-exposure areas where the radiation dose should be reduced, another function known as SPOT ROI has also been found to be effective in routine clinical practice.
Various functions that allow the operator to collimate the region of interest (ROI) within the overall field of view are available in the systems produced by other companies, but these functions tend to be rather difficult to use because the area outside the ROI is displayed in black.
The SPOT ROI function in Alphenix, on the other hand, continues to show the surrounding anatomy. It is like covering the image with a thin cellophane film with an opening that matches the area of the ROI (Figure 2).
Using this function, the image quality within the ROI is maintained at the usual level, and surrounding areas can also be observed to some degree. This means that the operator can perform procedures at a lower radiation dose while still being able to observe changes that may occur quickly. In fact, the measurement results showed that Spot ROI can reduce the dose in surrounding areas by 65-85%. It is also easy to operate the ROI, which minimizes the burden on the operator and makes it possible to perform less-invasive therapeutic procedures.
The speed of C-arm movement is another critical factor during cardiac imaging, in which images must be acquired from various angles. The four systems produced by different companies were compared in terms of the time needed to move the C-arm to specified positions during a set of routine examination procedures. Alphenix was found to be the fastest, at one minute 40 seconds, resulting in more efficient operation. The time needed for the systems produced by the other companies was two minutes or more. One of the reasons for the higher speed of Alphenix is that its flexible wide arm opening minimizes interference (Figure 3).
Figure 4 Evaluation of arm movement
Alphenix also allows the operator to simulate the working angle based on 3D CT data obtained before the procedure is started. For example, in patients with severe renal dysfunction, who need to be examined with the smallest possible amount of contrast agent, the most effective angle for observing a lesion can be identified by reviewing previously acquired 3D CT data. This information can then be preloaded into Alphenix, allowing the lesion to be easily observed from the optimal angle. Consequently, the number of image acquisitions is reduced, and the amount of contrast medium is minimized, resulting in a less invasive interventional procedure (Figure 4).
What’s more, Alphenix which comes with an optional tablet console, allowing a variety of operations to be performed easily by pressing a single key or button on the tablet. For example, the viewing mode can be changed through one-touch operation to change the monitor display settings. In addition, the arm angle can be registered in advance and visually indicated on the display. Even though the operator may not remember the actual settings, the desired angle can easily be selected. The workstation can also be operated using the tablet.
For example, the operator can rotate and view 3D images to determine the optimal working angle. This design allows the operator to work at the tableside in many situations that are encountered in actual clinical practice.
Figure 4 Evaluation of arm movement
Installation of the first “Alphenix Biplane” system
Toyohashi Heart Center was established in 1999 as a ‘clinic’ (a medical institution with 0-19 beds, as defined by the Medical Care Act of Japan). The center initially provided services from just two catheterization laboratories; however, the number of beds were later increased, and the center was reclassified as a ‘hospital’. Toyohashi Heart Center now provides services with total of four catheterization laboratories.
Since its establishment, the center has used angiography systems produced by a range of manufacturers – one by Canon Medical Systems (previously known as Toshiba Medical Systems), and another three by a variety of companies. It was under this arrangement that the Alphenix Biplane system (a state-of-the-art solution from Canon Medical Systems) was installed in Cath Lab 1. As of October 26th 2018, this was the company’s first commercial installation of the Alphenix Biplane in the world, and the system has been in operation at the Toyohashi Heart Center ever since.
First, there is no doubt that image quality has been markedly improved. We usually perform fluorography at 7.5 fps, which provides acceptable image quality and allows procedures to be conducted comfortably and efficiently, even in complicated patients with chronic total occlusion (CTO). The exposure dose is equal to or lower than that of the systems produced by other companies and has been found to be completely acceptable in clinical use. The system also provides advanced functions such as DTS, which allows the operator to be fully aware of the exposure dose, and SPOT ROI, which allows the dose to be further reduced. Alphenix offers many advantages for both patients and operators, and we look forward to making the best possible use of the system. We have high expectations for this system in the future due to its outstanding benefits, including high-speed C-arm movement and improved workstation operability. //