Mirror image artifact - mimicking pleural effusion

Case contributed by Mostafa Elfeky
Diagnosis almost certain


Follow up liver cirrhosis.

Patient Data

Age: 50 years
Gender: Male

Advanced liver cirrhosis is noted with no focal lesions and patent portal vein. Moderate splenomegaly (23 cm) and massive ascites are noted. No pleural effusion.

Case Discussion

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.

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