What does CVR mean in MEDICAL PHYSICS

Cerebrovascular Resistance, or CVR, is a measure of how difficult it is for blood to flow through the blood vessels in the brain. The resistance is determined by measuring the pressure gradient between two points in the vasculature and then taking into account factors such as vessel diameter, flow rate, and viscosity. CVR can be used to evaluate overall circulatory health and diagnose certain conditions such as stroke and hypertension.

High Cerebrovascular Resistance can lead to an insufficient supply of oxygen to the brain, which can cause headaches, vertigo, confusion, and other symptoms consistent with stroke or transient ischemic attack (TIA). In more severe cases of high CVR, it can also lead to seizures and coma.

CVR is typically measured using transcranial Doppler ultrasonography. This method uses sound waves to measure blood flow velocity at various points along the vessels in the brain. The pressure created by the sound waves helps create a picture that allows physicians to pinpoint specific areas where there may be higher resistance levels due to narrowing or other blockages in the blood vessels.

High CVR increases risk for stroke because it reduces blood flow, leading to reduced oxygen delivery throughout the brain. When oxygen levels drop too low due to increased resistance in some areas of the vasculature, this can lead to tissue death (ischemia) and ultimately a stroke if not addressed quickly enough.

Treatment for high CVR varies depending on underlying cause. Depending on what factors are causing increased resistance (e.g., narrowing or occlusion of blood vessels), doctors may recommend medication (such as ACE inhibitors), lifestyle changes (i.e., increased exercise/diet modifications), endovascular procedures (i.e., balloon angioplasty), or even surgery if necessary.

Not necessarily; although hypertension often leads to elevated CVR readings due its effects on arterial walls, other conditions such as hypoxia (low oxygen levels) and vascular stenosis (narrowing of vessels) can also contribute significantly to raised pressure readings during transcranial tests of CVR.

Yes – studies have consistently linked smoking cigarettes with markers of higher cerebrovascular resistance including lower mean flow velocities during imaging scans compared with nonsmokers.

Yes - individuals with lower than average cerebrovascular resistance scores have been observed with remarkably higher rates of cognitive decline compared with their peers who have normal-to-high cerebral resistances.

Yes – Exercise has been shown to decrease overall resistance while increasing overall perfusion throughout the vasculature in general.