Systems and methods for determining intracranial pressure non-invasively and acoustic transducer assemblies for use in such systems

Abstract

Systems and methods for determining ICP based on parameters that can be measured using non-invasive or minimally invasive techniques are provided. Systems for acquiring acoustic data from a desired target site in a subject's body using various types of acoustic source and detector elements are also provided, including single use acoustic source/detector combinations are also provided. Acoustic arrays for use with these systems may include multiple capacitive micro-machined ultrasound transducer (cMUT) elements, and may include a combination of different types of acoustic arrays. Methods of targeting localized sites within a broad target area based on acoustic data having various properties are also disclosed.

1 . A system for determining the ICP of a subject based on at least two variable inputs, comprising: a data acquisition component mountable to a subject's body surface and having at least one acoustic source element and at least one acoustic detector element; and a controller component comprising a signal generator providing acoustic interrogation signals to the at least one acoustic source element and a data processing component receiving a first variable input comprising acoustic data signals from the at least one acoustic detector element and receiving a second variable input selected from the group consisting of: ABP, CNS tissue stiffness, CNS tissue displacement, partial pressure of at least one or more gases associated with CNS respiration and metabolism, pCO 2 , blood perfusion, hematocrit, and electrophysiological properties, the data processing component being programmed to determine ICP based on the first and second variable inputs. 
   
   
       2 . A system of  claim 1 , wherein the data acquisition component comprises an acoustic transducer array. 
   
   
       3 . A system of  claim 1 , wherein the acoustic transducer array comprises a plurality of cMUT transducer cells. 
   
   
       4 . A system of  claim 2 , wherein the acoustic transducer array comprises a PVDF acoustic transducer array. 
   
   
       5 . A system of  claim 2 , wherein the acoustic transducer array comprises a plurality of PZT acoustic elements. 
   
   
       6 . A system for acquiring acoustic data from a desired target site within a subject's body, comprising: a data acquisition component mountable to a subject's body surface and having at least one acoustic source element and at least one acoustic detector element, at least one of the source and detector element(s) comprising an acoustic transducer array composed of multiple cMUT acoustic transducer cells arranged in a (single) thin layer; and a controller component in operable communication with the data acquisition component, the controller component comprising a signal generator providing energy for acoustic interrogation signals to the at least one acoustic source element and a data processing component receiving acoustic data signals from the at least one acoustic detector element. 
   
   
       7 . A system of  claim 6 , wherein the system is operable as a transcranial Doppler device and the data processing component is capable of Doppler processing acoustic data signals. 
   
   
       8 . A system of  claim 6 , wherein the data acquisition component is operable in a scanning mode to acquire acoustic data from a predetermined or selectable target area; the controller component identifies a desired target site based on acoustic data acquired in scanning mode; and the controller component focuses at least a portion of the acoustic source and acoustic receiver elements on the desired target site for acquisition of acoustic scatter data. 
   
   
       9 . A system of  claim 6 , wherein at least a portion of the source and detector elements are steerable and the controller component is programmed to scan at least one target area having a predetermined boundary or predetermined parameters prior to focusing the acoustic source and acoustic receiver elements on the desired target site. 
   
   
       10 . A system of  claim 9 , wherein the controller component is additionally programmed to locate one or more target sites within the target area based on preselected or selectable acoustic properties. 
   
   
       11 . A system of  claim 6 , wherein the data acquisition component comprises a cMUT acoustic transducer array composed of multiple cMUT cell structures, at least a portion of which are operable in a transmit mode and at least a portion of which are operable in a receive mode. 
   
   
       12 . A system of  claim 6 , wherein the data acquisition component comprises a single use cMUT acoustic transducer array composed of multiple cMUT cell structures and a data communication component for sending data to and/or receiving data from the controller component. 
   
   
       13 . A system of  claim 6 , wherein the data acquisition component additionally comprises a PZT acoustic transducer operable as an acoustic source and a cMUT array operable as an acoustic detector. 
   
   
       14 . A system of  claim 6 , wherein the controller component is capable of relating a first variable input derived from acoustic scatter data and second variable input relating to a physiological property of a subject to ICP using a non-linear relationship, wherein the second variable input is selected from the group consisting of ABP, CNS tissue stiffness, induced and/or intrinsic CNS tissue displacement, partial pressure of one or more gases associated with CNS respiration and metabolism, pCO 2 , blood perfusion, hematocrit, EKG and electrophysiological properties. 
   
   
       15 . A system of  claim 6 , wherein the first variable input is flow velocity in an intracranial blood vessel and the second variable input is ABP. 
   
   
       16 . A system of  claim 6 , wherein the source and detector elements comprise an acoustic source/detector combination having multiple capacitive micro-machined ultrasound transducer (cMUT) elements, each transducer element being independently controlled or controllable. 
   
   
       17 . A single use acoustic source/detector combination mountable to a subject's body surface and having at least one acoustic source element and at least one acoustic detector element, at least one of the source and detector element(s) comprising an acoustic array composed of multiple acoustic transducers, the source/detector combination additionally comprising an acoustically transmissive material arranged to provide high fidelity acoustic transmission between the source and detector element(s) and the subject's body surface during operation. 
   
   
       18 . A single use source/detector combination of  claim 17 , wherein the acoustic array comprises a plurality of cMUT transducer cells. 
   
   
       19 . A single use source/detector combination of  claim 17 , wherein the plurality of cMUT transducer cells is arranged in a thin layer. 
   
   
       20 . A single use source/detector combination of  claim 17 , wherein the acoustic array comprises a PVDF acoustic array. 
   
   
       21 . A single use source/detector combination of  claim 17 , wherein the acoustic array comprises a plurality of PZT acoustic transducers. 
   
   
       22 . A single use source/detector combination of  claim 17 , additionally comprising an adhesive contact material facilitating temporary mounting of the single use acoustic source/detector combination to the subject's body surface. 
   
   
       23 . A system for acquiring acoustic scatter data from a desired target site within a subject's body, comprising: two acoustic arrays, each composed of at least one transducer elements, the two arrays being aligned generally orthogonal to one another, with one array capable of sweeping in a first orientation in send and receive modes and a second array being capable of sweeping in a direction generally orthogonal to the first orientation in receive and send modes. 
   
   
       24 . A system for acquiring acoustic data from a desired target site within a subject's body, comprising: an acoustic source/detector combination including a PVDF transducer array serving as an acoustic detector and an acoustic source transducer or array transmitting through the PVDF array. 
   
   
       25 . The system of  claim 24 , wherein the acoustic source is a cMUT array or a single element PZT transducer. 
   
   
       26 . A system for acquiring acoustic data from a desired target site within a subject's body, comprising: an acoustic source/detector combination including an acoustic source transducer comprising a PZT transducer, and a transducer array serving as an acoustic detector, wherein the PZT acoustic source transducer transmits through the acoustic detector array. 
   
   
       27 . The system of  claim 26 , wherein the acoustic detector array is a PVDF or cMUT transducer array. 
   
   
       28 . A method for targeting a localized target site within a broad target area, comprising acquiring acoustic data from multiple points within the broad target area, selecting at least one localized target site within the broad target area based on acoustic data selected from the group consisting of acoustic scatter data, phase or frequency of acoustic scatter data, changes in the primary and/or other maxima and/or minima amplitude, phase or frequency of acoustic signals within a cardiac and/or respiratory cycle; tissue stiffness properties, endogenous and/or induced tissue displacement properties, acoustic emissions associated with such displacements and rates of change of such properties acquired from the multiple points within the broad target area, and focusing elements of the transducer assembly on the selected localized target sites. 
   
   
       29 . The method of  claim 28 , additionally comprising collecting data from a plurality of predetermined or programmed target sites at predetermined time points.