E-Z-EM’s EmpowerCTA is lightweight and features a flexible tilt sensor.

Structural imaging, specifically in the areas of CT, MRI, and ultrasound, is an evolving field, with the amount of time required to obtain an image, the image quality, and patient comfort acting as the driving forces behind the technological advancements. The use of contrast agents and injectors has played a major role in the progression of quality, timing, and care. Dr Dennis Foley is professor of radiology at the Medical College of Wisconsin (Milwaukee). He says, “Vessels must have sufficient concentrations of contrast agent to be in the X-ray,” and the sufficient amount of contrast must be delivered at a sufficient rate.

Contrast injector manufacturers have concentrated on developing easy-to-use injectors that deliver contrast at sufficient rates while allowing for additional timing and safety capabilities, such as saline flush, saline test inject, and extravasation detection. A variety of companies manufacture a range of contrast injectors suited for specific CT, MRI, or ultrasound techniques, with varying capabilities and features. Contrast agent manufacturers also have focused on developing products that are matched to specific techniques and target areas, while reducing patients’ potential pain and burning sensations.

Injection Lesson
Several key players are in the contrast-injector market, including the Bracco Group, E-Z-EM Inc, and Medrad. The Bracco Group manufactures contrast injectors through its wholly owned organization, Acist Medical Systems Inc (Eden Prairie, Minn). Barbara Wolf, product manager at Acist, says that the company manufactures its Contrast Management System (CMS) primarily for cardiac catheter procedures and its Voyager for multiprocedural uses. Both systems use hand-control devices to help limit the amount of contrast that is dispensed to the patient.

According to the company, “CMS is a variable-rate injection system that offers the physician complete control of the rate and volume of contrast delivered to the patient through the use of a single sterile hand piece.” Contrast waste reduction is also a focus for Acist in that a disposable syringe can be used with the Voyager for as many as five cases.

E-Z-EM Inc (Westbury, NY) is a one modality–oriented company that manufactures contrast injectors for CT applications. According to Phil Waldstein, global product manager for E-Z-EM, the company has focused on the CT market for the manufacturing of equipment and parts, the servicing of equipment, and even co-marketing the Ultravist CT contrast agent with Berlex Laboratories.

E-Z-EM recently released a double-barrel contrast injector, the EmpowerCTA, in addition to the single-barrel EmpowerCT. According to E-Z-EM, the EmpowerCTA offers all of the same features and benefits of the EmpowerCT—including being small, lightweight, and flexible with a tilt sensor; the capability of arming at the injector; preloaded syringe options; and a syringe warmer option. However, the new double-barrel CT injector is geared toward today’s advanced CT procedures that require the use of a saline chase.

Waldstein explains that this double-barrel saline flush system pushes a column of saline after the contrast “to keep the contrast bolus nice and tight and going at the right speed.” The system creates an even distribution of contrast while reducing the amount of contrast load.

Additionally, E-Z-EM offers detection capabilities with its injector, the patented Extravasation Detection Accessory (EDA). “The EDA pauses the injector and allows the technician to get to the patient before a serious extravasation can occur,” Waldstein says. As technology advances and flow rates increase, the potential of a forcing out does not increase, but the increased flow rate could have an effect on the seriousness of the extravasation. The company claims that after a 10-second injection at 2.0 mL/sec, a 20 mL extravasation results—referred to as “clinically significant, but not yet serious.” After a 10-second injection at 10 mL/sec, 100 mL of contrast—“as large as a billiard ball”—would be extravasated.

The pressure monitor graph on Medrad’s Stellant system displays real-time pressure during the injection.

Medrad Inc (Indianola, Pa) manufactures contrast injection systems for several applications, including angiography, CT, MR, and ultrasound. In the CT application, Medrad offers two contrast injectors: the Stellant Sx single-syringe system and the Stellant D dual-syringe system, the latter of which is for more advanced CT applications. According to Terry Heagy, clinical specialist for CT products at Medrad, the added saline injector in the Stellant D dual-injector system provides a tighter bolus and reduced contrast volume. Also, the system allows for the ability to test the injection site with saline prior to the injection of contrast to ensure the patency of the vein.

The Stellant user interface provides a color touch screen to display injector system operations—such as a pressure monitor graph, which shows the pressure being developed in the syringe during an injection, and the Flow Profile, which provides a real-time graphic display of the entire injection profile.

Dr David Dowe of Atlantic Medical Imaging (Somers Point, NJ) uses the Stellant D injection system. Specializing in coronary CT exams, Dowe says, “The Stellant user interface is easy, reliable, pretty, and the technologists like it.” The benefit of the dual injector, he adds, is the reduction of contrast to the patient and the reduction of cost.

Medrad’s Spectris Solaris MR injection system was launched last year as the second generation to the Spectris. Bonnie Cowan, product manager of MR injector systems at Medrad, says that the Spectris Solaris was designed based on user feedback, which suggested feature additions for saving space, flexibility, and increased saline amounts. Compared to five in the first generation unit, only two main components now comprise the Spectris Solaris: the injector head and stand, which are located in the procedure room and are connected via fiber-optic cables to the display control unit located outside the room. The battery charger is now remote and independent from the display control unit, making the charger concealable.

“Customers asked for more saline,” Cowan says, so Medrad increased the size of the saline syringe from 65 mL to 115 mL for KVO [keeping the vein open] and saline flush procedures. Also, she explains, many efforts were placed in software enhancements for the Spectris Solaris. The system offers a color touch screen, graphical depiction of syringes, and independent functioning of KVO from the injection profile. The six user-defined injection-control phases, along with the Medrad-patented Hold & Pause programming function, allow for test injections without the need to arm and disarm the injector. “This functionality helps with throughput and speed of procedures,” Cowan adds.

Magnevist from Berlex Laboratories was the first contrast agent available in the 100-mL pharmacy bulk package.

Secret Agents
As with injectors, contrast agents are produced by a variety of companies, including Amersham Health (now a part of GE Healthcare), Berlex Laboratories, and Mallinckrodt. The predominant contrast agents produced by Amersham Health (Princeton, NJ) are Omni-paque and Visipaque for X-ray applications, Omniscan for MRI applications, and Optison for ultrasound. Omnipaque is a low-osmolar, nonionic, iodinated contrast agent.

According to Steven Dowdell, director of marketing services for Amersham Health, Omnipaque—with 36 indications and five concentrations—is the gold standard in nonionic contrast agents. Now available in a new polymer bottle that is lighter, smaller, and safer than standard glass bottles, it includes a twist-off cap, peel-off tracking labels, and a latex-free bull’s-eye stopper plus a pull ring (both for easy access). The polymer bottle can be accessed with a syringe, a power injector syringe, and an IV set.

Visipaque from Amersham Health now comes in a polymer bottle, which includes a twist-off cap and peel-off labels.

Visipaque, also for X-ray applications and available in the new polymer bottle, is one of the only isosmolar contrast media available in the United States. Dowdell explains that Visipaque is good for use with compromised patients. And according to the company, the agent has an osmolality equal to that of blood, was designed for patient safety and comfort, and is well tolerated in the kidneys.

Amersham’s nonionic contrast agent for MRI, Omniscan, is “high dose and high speed,” Dowdell says. It has no maximum volume limit, is indicated for standard and triple-dose procedures, and offers rapid bolus injection. Omniscan is available in prefilled syringes, glass vials, and a SafePak needle-free delivery system.

Finally, Optison is Amersham’s contrast agent for ultrasound imaging of the heart. It is indicated for use in patients with suboptimal echocardiograms to opacify the left ventricle and to improve the delineation of the left ventricular endocardial borders. Says Dowdell, Amersham’s support staff features doctors on hand to answer callers’ questions, and the company funds many studies.

Used in 75-plus countries, Ultravist from Berlex Laboratories can be used for myriad applications, including head and body CT. This contrast agent has been used on more than 60 million patients.

Berlex Laboratories (Montville, NJ) manufactures an array of imaging agents, including Feridex IV, Magnevist, and Ultravist. Feridex IV is a paramagnetic, iron oxide, liver-specific MR agent that was the first organ-specific MRI contrast available in the United States for detecting and evaluating liver lesions. Magnevist was the world’s first, and is one of the most widely used, MR contrast agents, explains Serge Wurman, director of business development for Berlex Labora-tories’ imaging division. And finally, Ultravist is a nonionic, iodinated contrast agent for use in CT, including applications in head and body CT, excretory urography, coronary arteriography, left ventriculography, and cerebral arteriography.

Mallinckrodt is the only company to have FDA clearance to inject its own manufactured agent (OptiMark) with its own manufactured injector (Optistar).

Mallinckrodt (St Louis) is a business unit of Tyco Healthcare that manufactures both contrast media and injectors for multiple applications. Two of the agents are Optiray and OptiMark. Optiray is an injectable, low-osmolar, nonionic contrast media agent that’s used primarily in X-ray applications. Optiray is available in an array of iodine concentrations as well as in Mallinckrodt’s Ultraject prefilled syringes. On the other hand, OptiMark is a gadolinium-based, IV contrast media for MR imaging of the brain, spine, and liver.

Additionally, Sales Director Matt Hewig explains that Mallinckrodt is the only company to have FDA clearance to inject its own manufactured agent (OptiMark) with its own manufactured injector (Optistar). Plus, Optistar is a dual-injector system for both contrast and saline.

Nici Lewis is a contributing writer for Medical Imaging.