To investigate your salivary gland swelling you may need an X-ray of your jaw/face, an ultrasound scan of the salivary glands and, if a stone or blockage is suspected, possibly a Sialogram where X-ray contrast is injected into the salivary gland which can show stones or strictures (narrowing) in the salivary gland drainage pathways. Occasionally, blood tests may be required and at times a CT scan or MRI scan might be necessary.