By Charles Bankhead

A comparison of CT and ultrasound guidance for percutaneous abdominal interventions shows comparable room and procedure times, but published data from the same investigators indicate CT time needs to fall even further to be competitive.

CT may be closing the gap on ultrasound as the guidance for percutaneous abdominal interventions, Duke University radiologist Dr. Douglas Sheafor reported at the RSNA Scientific Session.

A comparison of CT fluoroscopy and ultrasound guidance showed comparable procedure times for both strategies. When diagnostic CT exams were removed from consideration, room time also was comparable between CT fluoroscopy and ultrasound.

"Ultrasound guidance for percutaneous intervention has been preferred at many centers because it is faster and less expensive," Sheafor said. "However, CT fluoroscopy appears to offer the possibility of CT localization with procedure times that are comparable to ultrasound guidance."

Sheafor and colleagues compared procedure times in 536 consecutive percutaneous interventions, comprising 325 tissue biopsies and 211 aspiration or drainage procedures. Guidance for the procedures include standard CT in 108 cases, CT fluoroscopy in 66, ultrasound with needle guide in 331, and ultrasound with Ultraguide in 31 cases.

Both ultrasound guidance methods had average room times of 76 to 77 minutes. In contrast, CT fluoroscopy had an average room time of 87 minutes, and the room time with standard CT averaged 90 minutes.

Limiting the analysis to CT fluoroscopy and ultrasound with Ultraguide, Sheafor and colleagues found that a considerable number of patients had diagnostic CT exams included in their total room time. When that time was subtracted from the analysis, the total room time for CT fluoroscopy was reduced to 76 minutes, no different from ultrasound guidance. All four guidance methods were associated with procedure times of 49 to 51 minutes.

Despite the favorable findings for CT fluoroscopy, Sheafor noted that a Duke team recently reported that CT room time would have to decline to less than 30 minutes to achieve equivalence or superiority to ultrasound in terms of cost.

"From that data, it would appear that ultrasound is still the most economical approach," he said.