An intravascular measurement device can be used to characterize a stenotic lesion in the body of a patient. In some examples, the intravascular measurement device is inserted into the patient and used to measure a physical dimension (e.g., diameter, cross-sectional area) of a blood vessel having the stenotic lesion during non-hyperemic blood flow. Thereafter, a pharmacologic vasodilator drug is introduced into the body of the patient so as to cause the patient to exhibit hyperemic blood flow rates. The intravascular measurement device may then be used to again measure the physical dimension of the blood vessel having the stenotic lesion, this time during hyperemic blood flow. A comparison between the physical dimension of the blood vessel during non-hyperemic and hyperemic blood flow can be used to characterize the stenotic lesion.
