His talk focused on the improvements and new parameters / modes of ultrasound that can help improve ultrasound imaging, hopefully to a quality that can compete with mpMRI. More importantly, if it gets to that point, its ease of use and combination with biopsy can make this a more effective tool for prostate cancer diagnosis – no need for 2 appointments, 2 different rectal preparations, fusion of imaging modalities, etc.
Prostate ultrasound, as with all ultrasound, is based on imaging obtained from pulses sound waves being sent at the tissue at a certain frequency, hitting the tissue and bouncing back – this information is processed into an image. However, the technology is rapidly improving – with much of the work being done in Europe and Asia.
There are 3 modes to his multiparametric ultrasound (mpUS) of the prostate.
1. B-mode (brightness mode) or Grey-scale – the “standard” imaging we think about when we do ultrasounds. Provides a 2D representation of the tissue.
- Traditionally, probes have used frequencies between 4-9 MHz – but this limits resolution in the tissue to 0.39 mm, which is not detailed enough to find and diagnose prostate cancer! Hence, the reason we moved to mpMRI.
- However, there are newer probes with frequency of 29 MHz – with resolution of tissue down to 70 micrometers. As context – capillaries are 50 micrometers and single prostate glands are ~70 micrometers. Diameter of clinically significant PCa is ~ 5 mm.
- Interestingly, due to increased resolution, PCa actually appears hyperechoic on this!
- Prostate cancer tends to be hypervascular – increased blood flow
- Prior studies from European and Asian cohorts have demonstrated increased sensitivity for PCa by targeting hypervascular areas
- Malignant tissue is more stiff than surrounding benign tissue
- Elastography has been demonstrated in smaller trials to have good sensitivity and specificity for PCa diagnosis
- There is a likert scale for ultrasound reporting
Presented By: Dan Rukstalis, Professor of Urology at Wake Forest University School of Medicine, Winston Salem, North Carolina
Written By: Thenappan Chandrasekar, MD, Clinical Instructor, Thomas Jefferson University Twitter: @tchandra_uromd, @TjuUrology at the 38th Congress of the Society of International Urology - October 4- 7, 2018 - Seoul, South Korea