Effectiveness of mastoid process percussion for identification of the vertebral artery ostium on Doppler studies.

Objectives: The pretransverse or first segment of the vertebral artery may be confused with adjacent branches of the proximal subclavian artery during Doppler assessment. This study investigated the effectiveness of mastoid process percussion, the "mastoid tap" maneuver, for identification of the vertebral artery ostium.

Methods: Fifty patients presenting consecutively for carotid sonography were recruited.

US findings of melamine-related renal disorders in Hong Kong children.

Background: The melamine-tainted milk incident has caused renal disorders in more than 290,000 children from mainland China since the start of the outbreak in 2008. Since then, more than 27,000 children in Hong Kong have undergone renal US screening.

Objective: To present and discuss the US features of melamine-related renal abnormalities in Hong Kong children.