4D ultrasound system promises shorter, more reliable scans

January 7, 2005

Vendors have long offered 3D and even 4D ultrasound systems. None has really caught on in radiology, mostly because they tend to lengthen diagnostic exams. Now GE Healthcare claims to have developed a 4D ultrasound product that actually shortens exam time.

Vendors have long offered 3D and even 4D ultrasound systems. None has really caught on in radiology, mostly because they tend to lengthen diagnostic exams. Now GE Healthcare claims to have developed a 4D ultrasound product that actually shortens exam time.

GE's Logiq 9 with 4D imaging obtains volumes of data that can be acquired quickly and interrogated later. Sonographers at Florida Hospital Celebration Health in Orlando have documented time savings of up to 68% with its use.

Before releasing the product commercially in October, the company tested it at clinical sites around the world. Several report anecdotal evidence not only of increased productivity, but improved reproducibility and diagnostic confidence.

"With volume imaging, you're assured of getting everything you need," said Dr. Deborah Rubens, associate chair of radiology and surgery at the University of Rochester Medical Center. "It standardizes exams, while providing us with new information and a new way to look at things."

The volume of data acquired using the Logiq 9 creates a kind of virtual scan that can be plumbed for new data, according to Dr. Nirvikar Dahiya, head of ultrasound at KG Hospital in Coimbatore, India, where he has used the Logiq 9 with 4D for about a year.

"It gives us the leverage that ultrasound had always lacked-the ability to reinterpret and reexamine data in different planes after the patient has left the examination table," he said. "Many times, while interpreting a diagnostically challenging case, I take multiple volume sweeps and additional cine loops and store them for reviewing later. This improves productivity."

Interrogating volumes of ultrasound data also affords the chance to get more from the scan. Planes never before possible are now within the grasp of radiologists.

"We don't acquire images in the coronal direction, but now we can start looking at this plane," Rubens said.

The information added by multiple or unique planes may be critical, according to Dahiya.

"The multiple rendering techniques that can be applied on the volume data-on a hollow viscous organ or a solid parenchymal structure-sometimes contribute a minuscule bit of extra information, but that can make all the difference in a diagnosis," he said.

Ultrasound scanners and workstations have been creating volumetric reconstructions for more than a decade. When these images were postprocessed, however, they could not be changed. GE took a different approach. The 4D transducers and software built into the company's enhanced Logiq 9 compile a volume of raw data on the fly. Once captured, this volume can be reconstructed into multiplanar or 3D images as needed.

"With this system, you can go to the source data if you don't see what you want the first time," said Terri Bresenham, vice president and general manager of global diagnostic ultrasound for GE.

Images acquired during the scan are displayed instantaneously.

"You can literally put the probe on the patient and see 3D in real-time," she said.

The data may be visualized on the scanner or on GE's offline workstation, LogiqWorks. Using the two in tandem, sonographers at Celebration Health cut scan times of 10 to 15 minutes with 2D imaging to between three and five minutes. Review times of five to 10 minutes using conventional means decreased to between three and five minutes using volumetric imaging. Report generation dropped from seven to 10 minutes to between five and seven minutes. Recalls dropped out of sight.

"After the doctors saw that they could rescan the volume of information, they waved off doing rescans," said J.P. Moreland, a senior sonographer at Celebration Health. "With this, you can essentially remove a kidney from the abdomen and put it on the system, so it can be replaned and rescanned for additional information."

A follow-up study provided a real-time snapshot of what might be possible with the enhanced Logiq 9 and its workstation. Whereas Celebration Health usually allows 45 minutes for each sonography patient, 10 patients were scheduled for the same sonographer in 90 minutes. Scans were completed in the allotted time on all 10, including two transvaginal exams, and the sonographer even had time for a cup of coffee, said Sally Grady, director of imaging services for Celebration Health.

"Usually, when staff are told they are going to be more productive, it means they are going to do the same amount of work with fewer people," Grady said. "Volume imaging gives us the best of both worlds, because it provides increased productivity in a way that doesn't stress the staff."

Volumetric imaging may be especially helpful when assessing nodules, such as those in the thyroid, according to Rubens. Typically sonographers can find five or even 10 nodules that must be measured individually in both the transverse and sagittal planes. In such a situation, it's easy to lose track of which nodule is which.

"But if you have them in a volume, you can just scroll through it," she said. "The next time that person comes in, it's easy to compare each nodule to what it looked like in the previous visit."

GE has developed three new probes that automate the acquisition of volumes and optimize data quality. The "belly buster," designed for use with obese patients, allows deep abdominal penetration through layers of adipose tissue. The other two probes are designed either for endocavitary or small parts imaging.

These probes and GE's 4D software can add $70,000 to the $180,000 price of the Logiq 9, bringing the total to a quarter-million dollars. GE recommends that customers complement the Logiq 9 with LogiqWorks, which combines GE's raw data processing algorithms with a multimodality Centricity PACS workstation. LogiqWorks, which costs $25,000, can display and process information from any digital modality. It also offers advanced clinical applications, including quick organ review, multiplanar measurement tools, and volume analysis.