Flow measurement through OCT

A system for diagnosing microvascular disease, comprising:

• an intravascular imaging probe;
• and
• one or more processors in communication with the intravascular imaging probe, the one or more processors configured to:
• receive, from the intravascular imaging probe, a plurality of intravascular image frames at a location within a blood vessel, wherein the location corresponds to where a bolus passes the intravascular imaging probe;
• determine a cross-sectional area of a portion of the bolus in the plurality of intravascular image frames including at least the portion of the bolus;
• create, based on the determined cross-sectional area of the portion of the bolus in the plurality of intravascular image frames including at least the portion of the bolus, a distribution curve;
• determine, based on the plurality of intravascular image frames including at least the portion of the bolus, a mean transit time of the bolus within the blood vessel;
• determine, based on the determined mean transit time, at least one of a coronary flow reserve (“CFR”) value or an index of microcirculatory resistance (“IMR”) value;
• and
• provide for output the determined at least one of the CFR value or the IMR value.

A non-transitory computer-readable medium storing instructions for diagnosing microvascular disease, which when executed by one or more processors, cause the one or more processors to:

• receive a plurality of intravascular image frames at a location within a blood vessel from an intravascular imaging probe, wherein the location corresponds to where a bolus passes the intravascular imaging probe;
• determine a cross-sectional area of a portion of the bolus in the plurality of intravascular image frames including at least the portion of the bolus;
• create, based on the determined cross-sectional area of the portion of the bolus in the plurality of intravascular image frames including at least the portion of the bolus, a distribution curve;
• determine, based on the plurality of intravascular image frames including at least the portion of the bolus, a mean transit time of the bolus within the blood vessel;
• determine, based on the determined mean transit time, at least one of a coronary flow reserve (“CFR”) value or an index of microcirculatory resistance (“IMR”) value;
• and
• provide for output the determined at least one of the CFR value or the IMR value.