Evaluation of the Particulate Concentration in a Gelatin‐Based Phantom for Sonographically Guided Lesion Biopsy

Objectives The purpose of this study was to determine the particulate concentration in a gelatin‐based ultrasound phantom for lesion biopsy at 6 cm in depth to reduce visualization of the biopsy needle in the near field, simulating subcutaneous fat and tissue echogenicity, and maintain target lesion visualization. Methods Four gelatin‐based phantoms with cornstarch at concentrations of 4, 8, 12, and 16 g/L and an anechoic gelatin target at 7 cm in depth were rated on a 5‐point scale by readers for visibility of the target lesion, similarity of near‐field to abdominal subcutaneous fat echogenicity, and visibility of a 22‐gauge spinal needle in the phantom. A timed sonographically guided localization task was performed on the anechoic target by 4 radiology residents using the 22‐gauge spinal needle. Results were analyzed by comparative statistical analysis. Results An increasing particulate concentration did not alter the similarity of near‐field to abdominal subcutaneous fat echogenicity (P = .6) but did significantly reduce visibility of the anechoic target at a cornstarch concentration of 16 g/L (P = .04) and the 22‐gauge needle at 12 g/L (P = .03). Decreased visualization of the needle or target lesion did not affect the time for needle localization of the anechoic target (P = .96). Conclusions The optimal ultrasound phantom cornstarch concentration was 12 g/L to reduce visualization of the spinal needle, simulating subcutaneous fat echogenicity while maintaining target lesion visualization.