Oncology - Prostate
Introduction & Objective :
Subhamonic imaging (SHI) is a new technique for imaging of microbubble ultrasound contrast agents with improved tissue suppression. We conducted a pilot study to evaluate contrast enhanced SHI of the prostate for detection of prostate cancer (PCa).
Fifty five patients referred for prostate biopsy were included in this study supported by a grant from the NIH: R21 CA202214. Each patient was imaged with a transrectal IC5-9D ultrasound transducer on modified Logiq E9 system (GE Healthcare; Milwaukee, WI) that was altered to perform SHI (transmit/receive: 7.0/3.5MHz). Ultrasound contrast was infused intravenously over 10 minutes using 3mL of Definity™ (Perflutren Lipid Microsphere, Lantheus Medical Imaging; N. Billerica, MA) diluted in 50mL of saline. Images were obtained using conventional grayscale, color and power Doppler, conventional contrast harmonic imaging (HI) as well as SHI and flash replenishment in combination with SHI (MIP-SHI). Doppler flow and contrast enhancement were rated on a 5 point subjective scale for each sextant of the prostate. Prostate biopsy was performed with up to 6 targeted cores based on contrast-enhanced imaging, followed by a 12 part systematic biopsy.
Contrast enhancement was clearly observed with both HI and SHI techniques in all subjects. SHI provided improved contrast signal and tissue suppression relative to conventional HI. Microvascular architecture and increased vascularity were best delineated with MIP-SHI. Each contrast enhanced technique demonstrated statistically significant predictive value for localization of PCa (p
This first in vivo application of contrast enhanced SHI in the prostate demonstrated enhancement in all patients, with focal areas of contrast enhancement predictive of PCa in targeted biopsy specimens. Detection of PCa included 9 patients whose PCa was not identified by MRI