Ultrasound poor (herniography good) at detecting clinically occult hernias

In this study, ultrasound had a sensitivity of 29% and specificity of 90% compared with the herniography. Correlation with surgical findings showed ultrasound to have a sensitivity of 33% and a specificity of 100%.

I'm not surprised about the ultrasound results. I can't comment on the herniography part, since I've only ever done one (many years ago), but maybe I'll need to start practising.

Adeeb Alam, Colin Nice and Raman Uberoi
The accuracy of ultrasound in the diagnosis of clinically occult groin hernias in adults
European Radiology 2005 (Dec) 15 (12): 2457 - 2461