What Does This Ultrasound Scan Of Upper Abdomen Indicate?

I undergone an ultrasound of upper abdomen. Result says both kidneys are normal in size and echogenicity. There is cortical calcification in the midpole of the left kidney measuring 0.53cm. The previously noted tiny stone in the left kidney is not evident. No focal mass lesion, ectasia nor calculi seen. Pls help explain to me this findings.