Methods for determining intracranial pressure non-invasively

A method for determining ICP of a subject based on at least three variable inputs, comprising:

• acquiring acoustic data from a target site on or in a cranial blood vessel of the subject and using, as a first variable input, the acoustic data or a measurement derived from the acoustic data;
• acquiring, as a second variable input, arterial blood pressure (ABP) data;
• acquiring, as a third variable input, physiological data relating to a physiological property other than blood flow velocity and ABP;
• and determining ICP based on the first, second and third variable inputs using a non-linear relationship.

A method for determining intracranial pressure (ICP) of a subject based on at least two variable inputs, each variable input being acquired using non-invasive techniques, comprising:

• acquiring acoustic data from a first target site on a cranial blood vessel of the subject and using, as a first variable input, the acoustic data or a measurement derived from the acoustic data;
• acquiring a second variable input relating to one or more acoustic properties of a target CNS site, the second variable input being different from the first variable input and being selected from the group consisting of:
• acoustic scatter and changes in acoustic scatter, including values of and changes in amplitude, phase and/or frequency of acoustic signals, values of and changes in length of scattered signals relative to the interrogation signal, values of and changes in the primary and/or other maxima and/or minima amplitudes of an acoustic signal within a cardiac and/or respiratory cycle;
• ratios of and changes in the ratios of the maximum and/or minimum amplitude to that of mean or variance or distribution of subsequent signals within a cardiac cycle, values of and changes in temporal or spatial variance of scattered or emitted signals at different times in the same target location and/or at the same time in different target locations, values of and rates of change of endogenous and/or induced tissue displacement or relaxation, acoustic emissions produced by the endogenous and/or induced tissue displacement or relaxation, and combinations thereof;
• and
• determining ICP based on the first and second variable inputs using a non-linear relationship.

A method for determining intracranial pressure (ICP) of a subject based on at least two variable inputs, comprising:

• locating and acoustically illuminating a desired target site in an automated fashion using an array comprising a plurality of acoustic source and/or detector elements by operating the array to acquire acoustic data from numerous sites within a larger target area, selecting at least one localized target site within the target area based on the acoustic data acquired for focused acoustic illumination and/or probing, and focusing the acoustic source and/or detector elements on the at least one selected localized target site and acquiring acoustic data from the at least one selected localized target site;
• using the acquired acoustic data from the at least one selected localized target site as a variable input;
• acquiring another variable input from acquired acoustic data or from an arterial blood pressure (ABP) measurement;
• and determining ICP based on the variable inputs using a non-linear relationship.