Toshiba America Medical Systems (Tustin, California) this week introduced a fourth generation contrast-free imaging technique, Time and Space Angiography (TSA).

Mark Totina, product manager for MRI at Toshiba America Medical Systems, told Diagnostics & Imaging Week that the TSA technique is designed to create images that show dynamic blood flow without using contrast agents.

"We are now able to electronically tag the blood and then start watching it as it flows so now we're seeing dynamic information over time, watching the blood flow through an organ without the use of contrast... it's dynamic flow," Totina said. "Before there was no way to see that blood flowing in motion over time without the use of contrast."

TSA will have a variety of clinical benefits to improve both diagnostic confidence and patient care and safety, Toshiba said. The technique builds on the company's Time-Spatial Labeling Inversion Pulse (Time-SLIP) technique and is especially desirable for patients with compromised circulations and renal flow problems, the company noted. It features an extremely high temporal resolution and a continually changing inversion pulse time, creating dynamic images showing blood flow in motion.

Toshiba is calling its new TSA its fourth generation contrast-free imaging technique, however Totina said the product is a "close cousin" to the company's Time-SLIP technique and could also be considered a second-generation technique to Time-SLIP.

Time-SLIP, he said, is useful for evaluating hemodynamic velocity, functional assessments, and visualization of vascular structures.

In patients with symptoms of stroke, TSA is intended to show blood flow into the brain and clearly display the area being impeded, which aids physicians in faster, more accurate diagnosis. For neurologists, the use of TSA will enable the diagnosis of cerebral spinal fluid diseases non-invasively, according to Toshiba.

The company also offers Fresh Blood Imaging (FBI), a non-contrast imaging technique introduced in 1998, and Contrast-free Improved Angiography (CIA), also a non-contrast imaging technique.

According to Toshiba, FBI is particularly well-suited for evaluating peripheral vascular diseases of the lower extremities. It acquires arterial and venous flow in a single coronal pass requiring less scan time than other MRA techniques. It also eliminates sensitivity to issues like improper timing, turbulent flow and differential filling that can cause contrast-based MRA to fail.

CIA, the company noted, adds systolic black blood imaging to reduce ghosting and improve arterial and venous flow separation.

Totina said the company's newest non-contrast imaging technique is intended to benefit the patient first and foremost, and then the clinician "because now for the first time ever they are able to see dynamic flow non-invasively."

Gadolinium-based contrast agents, commonly used in MRA, have been directly linked to nephrogenic systemic fibrosis, also known as nephrogenic fibrosing dermopathy (NSF/NFD), a sometimes-fatal disease that occurs in patients with renal insufficiency. According to a recent study by rheumatologists at Massachusetts General Hospital (Boston), NSF cases could reach epidemic proportions. The study found that NSF affected 30% of hemodialysis patients who were exposed to gadolinium during a MR exam. Previous studies had estimated only a 2% to 5% incidence for developing NSF after receiving gadolinium.

"We have been at the forefront of contrast-free imaging, offering our customers safe, contrast-free techniques that capture images equal to, and in many cases superior to, images captured using contrast," said Bob Giegerich, director, MR business unit at Toshiba. "We are fully committed to patient safety and continue to create new contrast-free MRA techniques that are advancing the industry. As more information is disseminated about the dangers of gadolinium-based contrast agents, it is crucial to have viable contrast-free techniques available."

Available on all Toshiba Vantage MR systems, TSA adds to Toshiba's suite of contrast-free MRA techniques including FBI, CIA, and Time-SLIP.

Toshiba provides diagnostic medical imaging systems and comprehensive medical solutions, such as CT, Cath & EP Labs, X-ray, ultrasound, nuclear medicine, MRI and information systems.