3D MRI Can Show Urinary Tract in Unprecedented Detail


CHICAGO — Truly three-dimensional magnetic resonance imaging of the urinary tract was performed in pediatric patients using newly developed software and imaging protocols, Dr. Paul Kokorowski said at the annual clinical congress of the American College of Surgeons.

Because the 3D MRI information was collected as slabs of data (volume pixels, or voxels) rather than as slices, it contained unprecedented anatomic detail. The scan was complete in about 10 minutes, and the 3D image was available almost immediately, with no need for time-consuming postprocessing, Dr. Kokorowski said.

“The program takes the MR information that is acquired every day and packages it as you'd want to use it. You can look through the anatomy before doing surgery,” said Dr. Kokorowski, a urologist at the University of Southern California and Childrens Hospital Los Angeles.

Dr. Kokorowski and his associates at Childrens Hospital worked with MRI experts to create the protocols for 3D MR urography.

At the meeting, they presented their results for six pediatric patients. The 3D images of the urinary tract aided the researchers' ability to evaluate and treat the children for various conditions, including ureterocele, an ectopic ureter, a duplex kidney, and a ureteropelvic junction obstruction.

The new protocols provided “a completely different way to look at patients preoperatively,” said Dr. Roger E. De Filippo of Childrens Hospital, the senior urologist who collaborated on the project.

Dr. Anthony Atala, a meeting attendee who is a professor and chairman of urology at Wake Forest University in Winston-Salem, N.C., commented that “this truly represents a whole new area of imaging, because you image volume instead of reprocessing sagittal data.”

Voxel MRI, known commercially as Volumap, was developed by Lee Schiel, president of Early Response Imaging in San Bernadino, Calif.

The method was introduced about 10 years ago in a project with the National Aeronautics and Space Administration to visualize structures that appeared to be bacteria on rocks collected on Mars.

In addition to developing urology protocols with the Childrens Hospital group, Mr. Schiel has worked with other clinical groups to develop ways to image the spine, the knee, and cardiac structures including heart valves.

The protocols developed so far are available commercially and can be used on any MRI scanner.

Because data acquisition is faster than in conventional MRI, cutting imaging time down to about 10 minutes, the increased patient throughput allows the cost per scan to remain about what it has been, Mr. Schiel said.

3D MRI eliminates the many pages of conventional MR slice-images that a physician needs to sort through to assess three-dimensional anatomy in a patient, said Dr. Kokorowski.

The fast acquisition time eliminates motion artifacts and the need to sedate patients during scanning. It also allows imaging of dynamic processes, such as blood leaking through a faulty heart valve. Dr. Kokorowski is hopeful that the images will provide a new way to measure glomerular flow rate.

A 3D magnetic resonance image shows a horseshoe kidney (red line) with the vasculature highlighted.

Another 3D MRIshows bilateral duplicated kidneys (red, blue lines) and ureters down to the bladder (green line). Photos courtesy Childrens Hospital of Los Angeles/Lee Schiel/Early Response Imaging

Next Article: