Robotic System for CT-guided Biopsies of Lung Lesions Shows Promise

By Mike Bassett

Andrea Porfiri, M.D.

Robot-assisted CT-guided biopsy of lung lesions can be used safely and accurately, particularly compared to conventional CT-guided biopsy techniques, according to a study presented Tuesday.

While CT-guided lung biopsy has become the standard procedure for obtaining a diagnosis of pulmonary lesions that are suspicious for malignancy, the two ways in which this procedure is usually performed—the "step-and-shoot" and fluoroscopic techniques—have their limitations, said presenter Andrea Porfiri, M.D., of the Department of Radiological Sciences, Sapienza University of Rome, in the session, "Preliminary Clinical Experience with a Dedicated Interventional Robotic System for CT-guided Biopsies of Lung Lesions: A Comparison with the Conventional Manual Technique."

According to Dr. Porfiri, the step-and-shoot technique relies on the operator's subjective assessment of needle path and positioning, which could result in longer procedure times with an increased risk of complications. On the other hand, the fluoroscopic technique is more accurate than the step-and-shoot technique when targeting smaller nodules, is of shorter duration and yields significantly lower complication rates. However, it is associated with a significant increase in radiation dose to both operator and patient.

"In both of these manual techniques, successful application depends significantly on the operator's manual skill and experience," Dr. Porfiri said. Consequently, he and his colleagues at Sapienza University wanted to assess the clinical performance of a dedicated robotic system compared to these conventional manual techniques.

For purposes of the study, 100 patients (63 males and 37 females between the ages of 48 and 88) who were referred for CT-guided lung biopsy of previously diagnosed lung lesions were randomly assigned to undergo a robot-assisted procedure or a conventional biopsy using the step-and-shoot technique.

According to Dr. Porfiri, the duration of the robot-assisted procedure ranged between 10-31 minutes—significantly less than the 18-42 minutes for the conventional procedure. Radiation dose was significantly reduced with the robot-assisted procedure, as well.

Dr. Porfiri and his colleagues determined that the diagnostic performance of robot-assisted procedure was similar to the manual procedure, with four patients requiring re-biopsy after the robotic procedure and three patients requiring re-biopsy after the manual procedure. They also found that the complication rates were similar.

"The result of our study demonstrates that the robot-assisted lung biopsy is accurate and safe, and the robot-assisted procedure can also reduce procedure duration and radiation dose compared to the conventional approaches," Dr. Porfiri said.

"Our study was performed by two operators (with 2 and 8 years experience performing CT-guided lung biopsies), and although a statistical analysis has not been performed to evaluate differences between the two operators, what impressed us was the reduction in time needed by both operators to complete the procedure with in the robot-assisted approach, compared to the unassisted technique," said Michele Anzidei, M.D., also of the Department of Radiological Sciences, Sapienza University, and the study's lead author.

While he expected to see that reduction in time for a less experienced operator, he was surprised to see a reduction in time for the experienced operator as well.

"Future research should be aimed at evaluating how operators with different levels of experience may benefit from robot assistance in daily clinical routine, and to assess potential differences in the clinical performance of robot-assisted procedures between expert and non-expert radiologists," Dr. Anzidei said.

"While we obtained encouraging results, these should be verified and reproduced on a larger number of patients, preferably in a multi-centric study," Dr. Anzidei concluded.

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