Clinical indications, not anatomy, can determine CT exam consistency

Researchers at Harvard University have demonstrated consistency in CT imaging studies using a computer-based protocol system that is based on clinical indications, rather than the anatomy that is imaged.

"Using a computerized or Web-based protocol guidance system organized by clinical indication, a consistent method for protocol selection can be achieved," said Kevin Reynolds, a radiologic technologist at Harvard.

The system has many advantages, according to Reynolds:

?more efficient study protocoling
?consistent comparison studies for oncologic evaluation and response to therapy
?ease of training new staff members and residents
?fewere rescans due to incorrect scan parameters

During a 12-month trial period, all requested inpatient and outpatient body CT scans were assigned to nonspecific appointment slots. Using the RIS, radiologists or body imaging fellows electronically protocoled each exam based on a list of 110 clinical indications, Reynolds said.

Each clinical indication was linked to a specific exam protocol. Thus, each selected protocol determined the scan parameters, including slice thickness, collimation and interval, the need for intravenous contrast, whether the contrast should be ionic or low osmolar, the injection rate, scan delays, and the need for oral prep or rectal contrast material, he said.

A total of 215 body CT scans (136 torso, 62 abdominal, and 17 chest) were retrospectively reviewed by two researchers based on the clinical indications to determine consistency of scan protocols chosen by the radiologists. Results of the trial showed that, of the 215 CT studies performed, 205 (95%) were appropriately protocoled in accordance with the stated clinical indications, Reynolds said.

Of the 10 (5%) remaining patients, six were overprotocoled, and four were assigned a less than optimal protocol, he said. Of 75 follow-up scans for the same clinical indication, only six (8%) led to a different scan protocol, he said.