Method and apparatus for enhancement of medical images

Abstract

Method and related apparatuses are described for performing automated ultrasound mammography with reduced nipple shadow effects. The breast is compressed in a direction generally toward the chest wall of the patient with one side of a compressive member which is preferably a membrane. The breast is scanned with an ultrasonic transducer array positioned in acoustic communication with the other side of the membrane. Beamsteering is used. The signals from the beamsteered energy are combined to generate one or more compound images having a reduced nipple shadow effect. An acoustic couplant is preferably applied between the breast and the membrane. The images of the sub-nipple region are also preferably enhanced by making comparisons with reference areas of the breast in areas away from the nipple shadow effected area. The images are preferably displayed to a user, either automatically or upon receiving a preference from the user.

1 . A method for performing automated ultrasound mammography with reduced nipple shadow effects comprising the steps of: 
 compressing a breast in a direction generally toward the chest wall of the patient with a first side of a compressive member;    scanning the breast with an ultrasonic transducer array positioned in acoustic communication with a second side of the compressive member, thereby transmitting and receiving ultrasonic energy into and from the breast tissue at a first beam angle and a second beam angle; and    combining signals from the received ultrasonic energy at said first and second beam angles to generate one or more compound images having a reduced nipple shadow effect.    
   
   
       2 . A method according to  claim 1  wherein the compressive member is a membrane.  
   
   
       3 . A method according to  claim 1  further comprising the step of applying an acoustic couplant between the breast and the compressive member.  
   
   
       4 . A method according to  claim 1  wherein the step of combining includes image enhancement to increase the brightness of a nipple shadow area between the nipple and the chest wall.  
   
   
       5 . A method according to  claim 4  wherein the image enhancement includes evaluating brightness values in one or more reference areas outside the nipple shadow area.  
   
   
       6 . A method according to  claim 5  wherein the image enhancement further includes dividing the reference area into a plurality of sub-regions and evaluating brightness values in each of the plurality of sub-regions of the reference area.  
   
   
       7 . A method according to  claim 6  wherein the image enhancement further includes dividing the nipple shadow area into a plurality of sub-regions and evaluating brightness values in each of the plurality of sub-regions of the nipple shadow area.  
   
   
       8 . A method according to  claim 5  wherein the image enhancement further includes generating a compensation function for increasing the brightness of the nipple shadow area based at least in part on the evaluated brightness values in the one or more reference areas.  
   
   
       9 . A method according to  claim 8  wherein the compensation function is stored as a look up table.  
   
   
       10 . A method according to  claim 9  wherein the look up table values are smoothed in order to make the image enhancement look more natural to a user.  
   
   
       11 . A method according to  claim 1  wherein the step of combining includes compounding two or more frames of data into a single frame of data.  
   
   
       12 . A method according to  claim 1  wherein the step of combining includes compounding three or more frames of data into a single frame of data.  
   
   
       13 . A method according to  claim 1  further comprising the step of displaying one or more images having a reduced nipple shadow effect to a user.  
   
   
       14 . A method according to  claim 13  wherein the one or more images are displayed automatically to the user.  
   
   
       15 . A method according to  claim 5  wherein the image enhancement is processed in a background process.  
   
   
       16 . A method according to  claim 15  wherein the enhanced images are displayed to user automatically.  
   
   
       17 . A method according to  claim 15  wherein the enhanced images are displayed to a user in response to input received from the user regarding the user's preference for image enhancement.  
   
   
       18 . A system for performing automated ultrasound mammography with reduced nipple shadow effects comprising: 
 a compressive member having first and second sides, dimensioned and positionable to compress a breast in a direction generally toward the chest wall of a patient by contacting the breast with the first side;    an ultrasonic transducer array positioned and arranged to be in acoustic communication with the second side of the compressive member;    an electronic beamformer in communication with the transducer array having electronics which can cause the transducer array to transmit ultrasound energy in a beam having a first angle and a beam having a second angle into the compressed breast; and    an image processing system being arranged and programmed to combine reflected signals from the ultrasound energy transmitted in the first and second angles such that the combined image has a reduced nipple shadow effect.    
   
   
       19 . A system according to  claim 18  wherein the compressive member is a membrane  
   
   
       20 . A system according to  claim 18  wherein the image processing system includes image enhancement to increase brightness of a nipple shadow area between the nipple and the chest wall.  
   
   
       21 . A system according to  claim 20  wherein the image enhancement includes evaluating brightness values in one or more reference areas outside the nipple shadow area.  
   
   
       22 . A system according to  claim 21  wherein the image enhancement further includes dividing the reference area into a plurality of sub-regions and evaluating brightness values in each of the plurality of sub-regions of the reference area, and comparing the brightness of the reference area with the brightness of the nipple shadow area.  
   
   
       23 . A system according to  claim 22  wherein the image enhancement further includes generating a compensation function for increasing the brightness of the nipple shadow area based at least in part on the evaluated brightness values in the one or more reference areas.  
   
   
       24 . A system according to  claim 18  further comprising a display in communication with the image processing system and arranged to display one or more images having a reduced nipple shadow effect to a user.  
   
   
       25 . A system according to  claim 24  wherein the one or more images are displayed automatically to the user.  
   
   
       26 . A system according to  claim 20  wherein the image enhancement is processed in a background process.  
   
   
       27 . A system according to  claim 26  wherein the enhanced images are displayed to user automatically.  
   
   
       28 . A system according to  claim 18  wherein the image processing system is programmed to compound two or more frames of data into a single frame of data.  
   
   
       29 . A method for performing automated ultrasound mammography with increased signal quality comprising the steps of: 
 compressing a breast with a first side of a compressive member;    scanning the breast with an ultrasonic transducer array positioned in acoustic communication with a second side of the compressive member, thereby transmitting and receiving ultrasonic energy into and from the breast tissue;    generating image data based at least in part on the ultrasonic energy received from the breast tissue;    defining an enhancement region of the image data for image enhancement related to brightness;    defining one or more reference regions within the image data; and    altering at least some brightness values within the enhancement region based at least in part on comparing the brightness of the enhancement region and the brightness of the one or more reference regions.    
   
   
       30 . A method according to  claim 29  wherein the enhancement region contains one or more known low signal areas.  
   
   
       31 . A method according to  claim 30  wherein ultrasonic energy is transmitted and received in a first beam angle and a second beam angle; and wherein the step of generating comprises combining signals from the received ultrasonic energy at said first and second beam angles to generate one or more compound images.  
   
   
       32 . A method according to  claim 31  wherein the one or more known low signal areas are in a region close to the edge of the image.  
   
   
       33 . A method according to  claim 31  wherein the one or more known low signal areas is a nipple shadow region.  
   
   
       34 . A method according to  claim 31  wherein the step of altering further includes dividing the one or more reference regions each into a plurality of sub-regions and evaluating brightness values in each of the plurality of sub-regions.  
   
   
       35 . A method according to  claim 34  wherein the step of altering further includes generating a compensation function for increasing the brightness of the enhancement region based at least in part on the evaluated brightness values in the one or more reference regions.  
   
   
       36 . A method according to  claim 35  wherein the compensation function is smoothed in order to make the alteration to the enhancement region appear more natural to a user.  
   
   
       37 . A method according to  claim 29  wherein the brightness values are the pixel values for pixels within the image data.  
   
   
       38 . A method according to  claim 29  wherein one or more images containing the altered brightness values are displayed automatically to the user.