Methods and systems for determining body lumen size

A tissue treatment system, comprising:

• a catheter comprising a balloon mounted on a catheter shaft;
• one or more syringes to fill the balloon with a fluid;
• a non-transitory computer readable memory storing instructions;
• and
• one or more processors configured to execute the stored instructions to cause the tissue treatment system to:
• fill the balloon with the fluid within a body lumen;
• detect a fluid parameter of the fluid over a period of time;
• determine a parameter curve of the fluid parameter, wherein the parameter curve includes the fluid parameter versus an independent variable over the period of time;
• compare the parameter curve of the fluid parameter to a reference curve, wherein comparing the parameter curve to the reference curve includes determining a ratio of a first independent-variable value at an inflection or an endpoint of the parameter curve to a second independent-variable value at a reference inflection or a reference endpoint of the reference curve;
• and
• determining, based on the ratio, a size of the body lumen or a neuromodulation parameter corresponding to the size of the body lumen.

A non-transitory computer readable medium storing instructions, which when executed by one or more processors of a tissue treatment system, cause the tissue treatment system to perform a method, comprising:

• filling a balloon with fluid within a body lumen;
• detecting a fluid parameter of the fluid over a period of time;
• determining a parameter curve of the fluid parameter, wherein the parameter curve includes the fluid parameter versus an independent variable over the period of time;
• comparing the parameter curve of the fluid parameter to a reference curve, wherein comparing the parameter curve to the reference curve includes determining a ratio of a first independent-variable value at an inflection or an endpoint of the parameter curve to a second independent-variable value at a reference inflection or a reference endpoint of the reference curve;
• and
• determining, based on the ratio, a size of the body lumen or the neuromodulation parameter corresponding to the size of the body lumen.