Final answer:
Having a blood clot in the brain would be a contraindication for receiving rt-PA for an ischemic stroke, unlike hypertension, recent surgery, and elevated cholesterol levels which are not direct contraindications.
Step-by-step explanation:
When determining if a patient can receive rt-PA for an ischemic stroke, there are certain contraindications to consider. One of these contraindications is having a blood clot in the brain. While hypertension, recent surgery, and elevated cholesterol levels are all risk factors for stroke, they are not direct contraindications for receiving rt-PA. A contraindication is a specific condition or factor that makes a particular treatment or procedure unsafe or unadvisable, and having a blood clot in the brain would be a contraindication for receiving rt-PA.