Axial images give way to coronal reformats in abdomen

May 15, 2006

Radiologists reported more findings and a higher degree of confidence using coronal reformatted images compared with axial images in routine abdominal CT, according to a team of researchers from Emory University School of Medicine.

Radiologists reported more findings and a higher degree of confidence using coronal reformatted images compared with axial images in routine abdominal CT, according to a team of researchers from Emory University School of Medicine.

If coronal image interpretation becomes the standard of care, the number of images sent to PACS and the interpretation time for each study would decrease, said lead author Dr. Sunit Sebastian, a research associate at Emory. He presented the study at the annual meeting of the Society of Computed Body Tomography and Magnetic Resonance in April.

For coronal image interpretation to become the standard of care, however, the radiology community needs a change in attitude, Sebastian said. Such a change would occur quickly if radiologists would use 3D postprocessing regularly.

"Advances in MSCT have substantially increased the number of axial slices radiologists must read, and it will continue to increase as vendors offer higher and higher slice CT scanners. It is imperative to prepare ourselves by using coronal reformats, not only because there are fewer images to interpret - up to a 40% decrease in the number of images - but also to provide more information," Sebastian told Diagnostic Imaging.

While the benefit of using coronal reformations in acute appendicitis has been documented, this study looks at the value of independent coronal reformatted images to evaluate routine CT of the gastrointestinal tract.

Sebastian and colleagues reviewed the records of 50 patients referred for MSCT for gastrointestinal tract indications. All patients were scanned on a 64 slice-CT scanner, although results would have been similar with a 16-slice scanner, he said. Technologists reconstructed the axial images at the CT console to obtain 0.625-mm multiplanar reformatted images. Postprocessing required less than a minute.

Two abdominal radiologists trained on 50 separate exams to overcome the learning curve associated with viewing coronal images. Initially, each reader reviewed only the coronal reformats of all patients. After three weeks, they reviewed axial images.

The average interpretation time of coronal reformats (5.5 minutes) and axial images (six minutes) did not differ significantly. But both readers reported significantly more findings on coronal evaluations (264 and 255) compared with axial images (232 and 227). The readers also reported higher confidence on coronal evaluations compared with axial images and had good interobserver agreement.

Conditions that readers were better able to delineate and identify on coronal reformats included retroperitoneal and mesenteric lymphadenopathy, cecal and terminal ileal pathologies, and vascular anatomy variants.

Radiologists at Emory routinely use coronal reformats for abdominal imaging. Sebastian said that residents prefer the coronal reformats and have started using them to enhance their diagnostic capabilities.

The next step, already begun, is evaluating coronal reformats for a wide array of indications including trauma and oncology, he said.

For more information from the Diagnostic Imaging archives:

Three-D PACS product moves advanced capabilities onto standard PCs

Radiologists use 3D tools to work smarter, not harder

Volumetric imaging drives 3D processing portability