The first stack (scanning on the mid-axillary line) shows suspected right pleural effusion which confirmed not to be existing on scanning at the mid-clavicular line.

On the first stack of images, scanning was done at the mid-axillary line which makes ultrasound beams to contact the right diaphragmatic obliquely resulting in mirror image artifact. On scanning at the mid-clavicular line (second stack), ultrasound beams are in perpendicular contact the diaphragm, where the suspected effusion disappears.

Mirror image artifact is a friendly artifact that allows the sonographer to exclude pleural effusion by the reflecting of the liver image into the thorax, the opposite occurs in our case. To avoid this, scan in different angles and positions to change the angle of insonation.