GI/GU experts seek accord to describe 'incidentalomas'

October 1, 2007

The rate at which radiologists find incidental lesions-particularly cysts or indolent cancers in the elderly-has increased so much that radiology societies and organizations are mobilizing to formulate reporting guidelines for these "incidentalomas." In 2005, a panel of experts barely reached consensus regarding incidental lesions found at ultrasound in the thyroid (see "Overread," July, page 10). The latest effort, spearheaded by the American College of Radiology, seeks to determine how to handle incidental findings in the kidneys, liver, adrenals, ovaries, and pancreas.

The rate at which radiologists find incidental lesions-particularly cysts or indolent cancers in the elderly-has increased so much that radiology societies and organizations are mobilizing to formulate reporting guidelines for these "incidentalomas." In 2005, a panel of experts barely reached consensus regarding incidental lesions found at ultrasound in the thyroid (see "Overread," July, page 10). The latest effort, spearheaded by the American College of Radiology, seeks to determine how to handle incidental findings in the kidneys, liver, adrenals, ovaries, and pancreas.

"Body imagers face this dilemma daily. Some feel if they don't pursue all incidental findings, it will put them at medicolegal risk," said Dr. Lincoln Berland, chair of the ACR panel of experts seeking consensus. "Others don't know how to report them."

Effective guidelines for treating and reporting these incidental findings rely on consensus regarding various metrics such as attenuation, consistency or homogeneity, number, and size. A 1-cm lesion in the kidney, for example, could have a higher attenuation measurement than the threshold of 20 Hounsfield units because of volume averaging. But it looks like a cyst. Should the radiologist recommend an additional thin-section scan or a pre- and postcontrast scan to more fully evaluate it? Or can the radiologist safely ignore it or recommend no further follow-up because these findings are very common?

"These are the types of questions we face," Berland said.

The potential exists to overutilize CT imaging, expose patients to unnecessary radiation, and risk further procedures. There are many downsides, from a cost standpoint, to pursuing these incidental findings, and the advantages are minimal because have no clinical significance, said Berland, who is chief of body CT and the 3D Imaging Lab at the University of Alabama at Birmingham.

This panel could run into the same problem experienced by the 2005 Society of Radiologists in Ultrasound consensus conference on incidental thyroid nodules: not enough peer-reviewed evidence.

"More information is always helpful," said Dr. N. Reed Dunnick, chair of the ACR body-imaging committee.

Whether there is enough evidence for the panel to come to consensus remains to be seen. Members may determine that a large study needs to be conducted to determine the clinical path of various lesions, he said.

"If that doesn't seem to be feasible, a panel of experts with the imprimatur of the American College of Radiology would be a substantive document to use in support of a radiologist who is following those recommendations," he said.