Abnormalities measured on 3D reconstructions of ultrasound images are more reliable and easier to reproduce than on two-dimensional (2D) ultrasound, researchers from Germany will explain on August 14th in a presentation at the International Neurosonology '97 conference sponsored by the World Federation of Neurology and the Bowman Gray School of Medicine of Wake Forest University.
According to Dr. Andreas Delcker, the lead researcher, reliability and reproducibility were especially valuable because patients in the study underwent more than one imaging examination.
While techniques like cerebral angiography remain the diagnostic gold standard, ultrasound is being applied in ways that were only dreams a few years ago.
Why are these dreams coming true today? As Delcker explained in an interview, new computer workstations are allowing 2D ultrasound data sets to be electronically reconstructed as 3D images.
Ultrasound is also less expensive than other well known imaging techniques such as MRI and CT.
In this study, Delcker and his two colleagues used a prototype magnetic sensor workstation to reconstruct transcranial ultrasound in 3D. The prototype workstation, manufactured by 3D Echotech in Munich, Germany, and recently available in Europe, is so new that its use in the United States has yet to receive formal approval by the U.S. Food and Drug Administration. (Such approval is pending and will probably occur during the fall of 1997.)
When analyzing the 3D images of transcranial ultrasound from 20 patients, Delcker and his colleagues found two things:
First, identification of intracranial arteries significantly improved
after the patients received an intravenous contrast agent.
Second, with the 3D images generated by the prototype workstation, the
researchers were able to make follow-up measurements that were more accurate
than measurements made on 2D images.
According to Delcker, the 3D reconstructions yielded more precise reference points within the cerebral anatomy.
"Thanks to the workstation," Delcker said, "we knew that follow-up imaging was showing us exactly the same level and same region in each patient as before."
Also, with the prototype workstation and the 3D reconstructions it generates, the researchers were able to choose the best perspective for viewing the intracranial arteries. With 3D, relationships among the arteries were easier to see and understand.
Future applications of contrast-enhanced transcranial ultrasound and 3D reconstructions include pinpointing cerebral hemorrhages. Thus, Delcker and his German colleagues as well as researchers at Bowman Gray, where Delcker was a visiting professor from January through July, may soon apply the lessons learned from this study of adults to the study of neonatal patients.
With those very young patients, ease of obtaining images will help researchers who measure the volume of cerebral hemorrhages and then obtain follow-up imaging to evaluate reduction.
Thanks to 3D reconstructions, defraction artifacts and the approximate measurements they cause on 2D transcranial ultrasound will vanish, like an echo from the past.
For further information, call Mark Wright (email: mwright@bgsm.edu) or Bob Conn (email: rconn@bgsm.edu) at 910-716-4587. Once International Neurosonology '97 has begun on August 13, call the conference press room at 910-724-6923.