Yes, this is a different type of ultrasound that looks at blood flow in arteries or veins (to diagnose MALS or other vascular disorders). Usually the ones I've had have been called a Mesenteric Artery Duplex Ultrasound. They are typically only done in 1 or 2 hospitals in major cities because the technician needs special training to know how to do them.

Yes- it is an ultrasound used to examine arterial blood flow- frequently done on lower extremities.
However, as @jhmontrose pointed out, for the abdominal arterial blood flow the technician has to be trained to perform these.
In my experience from work up for my own difficult to diagnose abdominal pain Doppler ultrasound was abnormal and the findings confirmed with CT angiogram.