Biopsy of Deep Pelvic and Abdominal Targets With Ultrasound Guidance: Efficacy of Compression.

Abstract

<b>OBJECTIVE.</b> The purpose of this study was to evaluate the utility of compression of tissues with the ultrasound transducer in decreasing distance to the biopsy target and establishing a safe percutaneous biopsy route to deep abdominopelvic targets. <b>MATERIALS AND METHODS.</b> Ultrasound-guided biopsies of nonsolid organ abdominopelvic targets performed from 2006 to 2017 were reviewed. Skin-to-target distance was measured on preprocedure CT scans for reference standard and on procedure ultrasound images for actual real-time distance after compression. The skin-to-target CT distance groupings were 0-3 cm, 3-6 cm, 6-10, cm, and > 10 cm. Deep targets were defined as > 6 cm. Differences in skin-to-target distance between static CT and compression ultrasound were calculated. Body mass index, procedure details, diagnostic yield, and complication rate were recorded. <b>RESULTS.</b> The biopsies of 389 patients (167 men, 222 women; mean age, 62.4 years; mean body mass index, 28.2) were assessed. Skin-to-target distance was 0-3 cm in 108 patients, 3-6 cm in 163 patients, 6-10 cm in 99 patients, and > 10 cm in 19 patients. A total of 118 deep targets were identified. The mean skin-to-target distance in the entire cohort was 5.0 cm on CT scans and 3.6 cm on ultrasound images with a 10% mean decrease in distance with ultrasound compression. For skin-to-target distances of 6-10 cm, distance decreased 39% at ultrasound, and for skin-to-target distances > 10 cm, distance decreased 48%. Thirty-three patients (8.5%) had no safe identifiable path for CT biopsy, most commonly because of intervening bowel, displacement of which at ultrasound allowed a safe biopsy trajectory. Ultrasound-guided biopsy had a diagnostic yield of 91.5% and a favorable safety profile. The complication rate was 1.3%. <b>CONCLUSION.</b> Application of compression with the ultrasound transducer decreased skin-to-target distance 40% or more for deep targets in addition to displacing bowel and establishing a safe path for biopsy in approximately 8.5% of cases.