Apparatus and method for imaging the relative motion of skeletal segments

Abstract

Apparatus provided for the measurement of skeletal joint motion in a subject which comprises a passive motion device, an imaging device and a processing system incorporating a means for real time digital sampling of images of moving joints, means for recognizing templates attributed to individual bones and tracking these automatically using cross-correlation functions and means for geometric transformation of the positional data to graphically display their relative motion over time. Also provided is a method for the automated measurement of the relative motion of skeletal structures in vivo using such apparatus and a method for the diagnosis of a pseudoarthrosis in a subject which comprises the use of such apparatus.

What is claimed is: 
     
         1 . An apparatus for measuring a skeletal joint motion in a subject comprising:
 a) a passive motion device adapted and configured to continuously move a skeletal joint of the subject through a range of motion, the passive motion device comprising:   a platform base having an upper surface, and   a passive motion platform further comprising a static platform connected to the upper surface of the platform base, a moveable platform connected to at least one of the static platform or the upper surface of the platform base, wherein the static platform is adjacent the moveable platform wherein movement of the moveable platform is achieved in operation by a motor in communication with the moveable platform; and   b) an imaging device adapted and configured to image the joint of the subject during a motion of the passive motion device.   
     
     
         2 . The apparatus of  claim 1 , wherein the imaging device is one of an X-ray tube and image intensifier with dosage control and a magnetic resonance scanner. 
     
     
         3 . The apparatus of  claim 1 , wherein the moveable platform is a laterally moveable platform. 
     
     
         4 . The apparatus of  claim 1 , wherein the moveable platform is situated on a support which lies on the upper surface of the platform base. 
     
     
         5 . The apparatus of  claim 3 , wherein the imaging device is one of an X-ray tube and image intensifier with dosage control and a magnetic resonance scanner. 
     
     
         6 . The apparatus of  claim 1 , further comprising a control arm for driving a movement of the moveable platform. 
     
     
         7 . The apparatus of  claim 1  further comprising a processing system. 
     
     
         8 . The apparatus of  claim 1  wherein the passive motion device is adapted to communicate a motion information to the imaging device during use. 
     
     
         9 . A method for obtaining an automated measurement of a relative motion of skeletal structures in vivo comprising:
 i) positioning a subject on a passive motion device adapted and configured to continuously move a skeletal joint of the subject through a range of motion, the passive motion device comprising: a platform base having an upper surface, and a passive motion platform further comprising a static platform connected to the upper surface of the platform base, a moveable platform connected to at least one of the static platform or the upper surface of the platform base, wherein the static platform is adjacent the moveable platform wherein movement of the moveable platform is achieved in operation by a motor in communication with the moveable platform;   ii) imaging the subject positioned on the passive motion device during the use session with an imaging device;   iii) collecting image data while the passive motion device is continuously moving the joint;   iv) sampling the collected image data and superimposing a time code on the collected image data;   v) tracking a template marked on an individual bone segment; and   vi) transforming a result of tracking to reflect a changing spatial relationship of the individual bone segment between image segments.   
     
     
         10 . The method of  claim 9 , wherein the imaging device is one of an X-ray tube and image intensifier with dosage control and a magnetic resonance scanner. 
     
     
         11 . The method of  claim 9 , wherein the passive motion device further comprises a moveable platform situated on a support which lies on the upper surface of the platform base. 
     
     
         12 . The method of  claim 11 , wherein the imaging device is one of an X-ray tube and image intensifier with dosage control and a magnetic resonance scanner. 
     
     
         13 . The method of  claim 9 , wherein a calibration step is carried out prior to the method steps i) to vi). 
     
     
         14 . The method of  claim 9 , wherein a relative motion of lumbar vertebrae L2 to L3, L3 to L4 and L4 to L5 are tracked simultaneously or separately. 
     
     
         15 . The method of  claim 13 , wherein a relative motion of lumbar vertebrae L2 to L3, L3 to L4 and L4 to L5 are tracked simultaneously or separately. 
     
     
         16 . The method of  claim 9 , wherein the method is for a diagnosis of a pseudoarthrosis in the subject, and the method comprising analyzing the relative motion of skeletal structures in the subject. 
     
     
         17 . The method of  claim 16 , wherein the imaging device is one of an X-ray tube and image intensifier with dosage control and a magnetic resonance scanner. 
     
     
         18 . The method of  claim 16 , wherein the moveable platform is a laterally moveable platform. 
     
     
         19 . The method of  claim 16 , wherein the moveable platform is situated on a support which lies on the upper surface of the platform base. 
     
     
         20 . The method of  claim 19 , wherein the imaging device is one of an X-ray tube and image intensifier with dosage control and a magnetic resonance scanner. 
     
     
         21 . The method of  claim 16 , wherein a calibration step is carried out prior to the method steps i) to vi). 
     
     
         22 . The method of  claim 16 , wherein a relative motion of lumbar vertebrae L2 to L3, L3 to L4 and L4 to L5 are tracked simultaneously or separately. 
     
     
         23 . The method of  claim 21 , wherein a relative motion of lumbar vertebrae L2 to L3, L3 to L4 and L4 to L5 are tracked simultaneously or separately. 
     
     
         24 . The method of  claim 20 , further comprising the step of presenting an output in graphical form.