Breast Ultrasound Scanning Promoting Patient Comfort and Improved Imaging Near Chest Wall

Abstract

An apparatus and related methods for scanning a breast are described, the apparatus comprising a frame defining an orifice shaped to allow the breast to be received therein, a compressive member secured to the frame across the orifice that compresses the received breast toward the patient's chest wall, and a transducer positioned in acoustic communication with the compressive member for imaging the breast therethrough. The frame holds a reservoir of acoustically conductive fluid that maintains the transducer in acoustic communication with the compressive member. In different preferred embodiments having different advantages, the compressive member comprises a flexible elastic membrane, a flexible inelastic membrane, or a rigid sonolucent plastic preformed into the shape of a chestwardly-compressed breast. Where the transducer comprises one or more linear array probes, various probe orientations and trajectories are described for generating a three-dimensional volumetric representation of the breast having reduced nipple shadow effects.

1 . An apparatus for scanning a breast of a patient, comprising:
 a frame defining an orifice, said orifice being shaped to allow at least a portion of the breast to extend therethrough;   a compressive member secured to said frame across said orifice, a first side of said compressive member compressing the breast toward a chest wall of the patient when said breast is extended through said orifice; and   a transducer positioned in acoustic communication with a second side of said compressive member opposite said first side for imaging the breast therethrough.   
   
   
       2 . The apparatus of  claim 1 , said orifice and compressive member being positioned in an approximately horizontal plane to receive the breast while the patient is in a substantially prone position. 
   
   
       3 . The apparatus of  claim 2 , wherein said compressive member comprises a stretchable membrane elastically compressing the breast upward toward the chest wall. 
   
   
       4 . The apparatus of  claim 3 , wherein said stretchable membrane exerts a total upward force on the breast in the range of approximately 2 pounds (8.9 Newtons) to 12 pounds (53.4 Newtons). 
   
   
       5 . The apparatus of  claim 3 , wherein said stretchable membrane comprises an elastomer selected from the group consisting of: silicone, latex, vinyl, nitrile, polyurethane, and neoprene rubbers. 
   
   
       6 . The apparatus of  claim 2 , wherein said compressive member comprises a flexible, non-elastic membrane tensionably compressing the breast upward toward the chest wall. 
   
   
       7 . The apparatus of  claim 6 , wherein said flexible, non-elastic membrane comprises a high-strength polyester film. 
   
   
       8 . The apparatus of  claim 1 , wherein said compressive member comprises a substantially rigid plastic having relatively high acoustic transparency, said substantially rigid plastic being pre-molded into a shape corresponding to a compressed breast. 
   
   
       9 . The apparatus of  claim 8 , further comprising an orifice array including said orifice and a plurality of similar orifices, each orifice being sized differently for receiving differently-sized breasts, each orifice having a corresponding pre-molded rigid plastic member corresponding to a breast size for that orifice. 
   
   
       10 . The apparatus of  claim 8 , wherein said substantially rigid plastic comprises a polycarbonate plastic having a thickness in the range of approximately 0.5 mm to 2 mm. 
   
   
       11 . The apparatus of  claim 8 , said orifice and compressive member being positioned in an approximately vertical plane to receive the breast while the patient is in a substantially upright position. 
   
   
       12 . The apparatus of  claim 1 , said transducer comprising a first linear array probe maintained in floatable physical contact with said compressive member, said first linear array probe being moved to successive positions across said compressive member while obtaining successive ultrasound slices sufficient to reconstruct a three-dimensional volumetric representation of the breast. 
   
   
       13 . The apparatus of  claim 1 , said transducer comprising a first linear array probe physically offset from said compressive member, said apparatus further comprising an enclosed reservoir at least partially defined by said frame and said compressive member, said enclosed reservoir maintaining an acoustically conductive fluid between said first linear array probe and said compressive member for establishing said acoustic communication therebetween, said first linear array probe being offsetably moved across said compressive member while obtaining a first set of ultrasound slices for constructing a three-dimensional volumetric representation of the breast. 
   
   
       14 . The apparatus of  claim 13 , said first linear array probe being oriented such that said first set of ultrasound slices corresponds to planes substantially perpendicular to a coronal plane. 
   
   
       15 . The apparatus of  claim 14 , said first linear array probe being oriented such that said first set of ultrasound slices also corresponds to planes substantially parallel to an axillary axis for that breast. 
   
   
       16 . The apparatus of  claim 13 , said first linear array probe being oriented such that said first set of ultrasound slices corresponds to planes at a first skewed angle, said first skewed angle being neither substantially parallel to nor substantially perpendicular to said coronal plane, whereby nipple shadow effects in said three-dimensional volumetric representation are at least partially reduced for locations underlying a nipple of the breast. 
   
   
       17 . The apparatus of  claim 16 , further comprising a second linear array probe physically offset from said compressive member and being offsetably moved across said compressive member while obtaining a second set of ultrasound slices for use in constructing said three-dimensional volumetric representation in conjunction with said first set of ultrasound slices, said second linear array probe being oriented such that said second set of ultrasound slices corresponds to planes at a second skewed angle, said second skewed angle being neither substantially parallel to nor substantially perpendicular to said coronal plane, said second skewed angle being substantially nonparallel to said first skewed angle, whereby nipple shadow effects in said three-dimensional volumetric representation are further reduced. 
   
   
       18 . The apparatus of  claim 16 , said offsetable movement of said first linear array probe having an arcuate trajectory such that said first set of ultrasound slices corresponds to planes at a multiplicity of skewed angles neither substantially parallel to nor substantially perpendicular to said coronal plane, whereby nipple shadow effects in said three-dimensional volumetric representation are at least partially reduced. 
   
   
       19 . The apparatus of  claim 1 , said orifice and compressive member being positioned in an approximately horizontal plane to receive the breast while the patient is in a substantially prone position, said orifice having an oblong shape with a major axis corresponding to an axillary axis of the patient for that breast. 
   
   
       20 . The apparatus of  claim 1 , said compressive member comprising a substantially rigid plastic having relatively high acoustic transparency, said substantially rigid plastic having pre-molded contours in the form of a compressed breast, said orifice having an oblong shape with a major axis corresponding to an axillary axis of the patient for that breast. 
   
   
       21 . A method for scanning a breast of a patient, comprising:
 receiving at least a portion of the breast through an orifice defined by a frame, the orifice being shaped to allow at least a portion of the breast to extend therethrough;   compressing the breast toward a chest wall of the patient using a first side of a compressive member secured to the frame across the orifice; and   scanning the breast with a transducer positioned in acoustic communication with a second side of the compressive member opposite the first side of the compressive member.   
   
   
       22 . The method of  claim 21 , said orifice and compressive member being positioned in an approximately horizontal plane to receive the breast while the patient is in a substantially prone position. 
   
   
       23 . The method of  claim 22 , wherein said compressive member comprises a stretchable membrane elastically compressing the breast upward toward the chest wall. 
   
   
       24 . The method of  claim 23 , wherein said stretchable membrane exerts a total upward force on the breast in the range of approximately 2 pounds (8.9 Newtons) to 12 pounds (53.4 Newtons). 
   
   
       25 . The method of  claim 23 , wherein said stretchable membrane comprises an elastomer selected from the group consisting of: silicone, latex, vinyl, nitrile, polyurethane, and neoprene rubbers. 
   
   
       26 . The method of  claim 22 , wherein said compressive member comprises a flexible, non-elastic membrane tensionably compressing the breast upward toward the chest wall. 
   
   
       27 . The method of  claim 26 , wherein said flexible, non-elastic membrane comprises a high-strength polyethylene film. 
   
   
       28 . The method of  claim 21 , wherein said compressive member comprises a substantially rigid plastic having relatively high acoustic transparency, said substantially rigid plastic being pre-molded into a shape corresponding to a compressed breast. 
   
   
       29 . The method of  claim 28 , further comprising:
 identifying, according to a size of the breast, a suitable member of an orifice array including said orifice and a plurality of similar orifices, each orifice being sized differently for receiving differently-sized breasts, each orifice having a corresponding pre-molded rigid plastic member corresponding to a breast size for that orifice; and   receiving said portion of the breast through the identified orifice.   
   
   
       30 . The method of  claim 28 , wherein said substantially rigid plastic comprises a polycarbonate plastic having a thickness in the range of approximately 0.5 mm to 2 mm. 
   
   
       31 . The method of  claim 28 , said orifice and compressive member being positioned in an approximately vertical plane to receive the breast while the patient is in a substantially upright position. 
   
   
       32 . The method of  claim 21 , the transducer comprising a first linear array probe, further comprising maintaining the first linear array probe in floatable physical contact with the compressive member while moving the first linear array probe across the compressive member, the first linear array probe obtaining ultrasound slices sufficient to reconstruct a three-dimensional volumetric representation of the breast. 
   
   
       33 . The method of  claim 21 , the transducer comprising a first linear array probe, the frame and compressive member at least partially defining an enclosed reservoir that maintains an acoustically conductive fluid between the first linear array probe and the compressive member for establishing the acoustic communication therebetween, further comprising offsetably moving the first linear array probe across said compressive member while obtaining a first set of ultrasound slices for constructing a three-dimensional volumetric representation of the breast. 
   
   
       34 . The method of  claim 33 , further comprising orienting said first linear array probe during said offsetable movement such that said first set of ultrasound slices corresponds to planes substantially perpendicular to a coronal plane. 
   
   
       35 . The method of  claim 34 , further comprising orienting said first linear array probe during said offsetable movement such that said first set of ultrasound slices also corresponds to planes substantially parallel to an axillary axis for that breast. 
   
   
       36 . The method of  claim 33 , further comprising orienting said first linear array probe during said offsetable movement such that said first set of ultrasound slices corresponds to planes at a first skewed angle, said first skewed angle being neither substantially parallel to nor substantially perpendicular to said coronal plane, whereby nipple shadow effects in said three-dimensional volumetric representation are at least partially reduced for locations underlying a nipple of the breast. 
   
   
       37 . The method of  claim 36 , further comprising offsetably moving a second linear array probe across said compressive member while obtaining a second set of ultrasound slices for use in constructing said three-dimensional volumetric representation in conjunction with said first set of ultrasound slices, said second linear array probe being oriented during said offsetable movement such that said second set of ultrasound slices corresponds to planes at a second skewed angle, said second skewed angle being neither substantially parallel to nor substantially perpendicular to said coronal plane, said second skewed angle being substantially nonparallel to said first skewed angle, whereby nipple shadow effects in said three-dimensional volumetric representation are further reduced. 
   
   
       38 . The method of  claim 36 , said offsetable movement of said first linear array probe having an arcuate trajectory such that said first set of ultrasound slices corresponds to planes at a multiplicity of skewed angles neither substantially parallel to nor substantially perpendicular to said coronal plane, whereby nipple shadow effects in said three-dimensional volumetric representation are at least partially reduced. 
   
   
       39 . The method of  claim 21 , wherein the orifice and the compressive member are positioned in an approximately horizontal plane to receive the breast while the patient is in a substantially prone position, and wherein the orifice has an oblong shape with a major axis corresponding to an axillary axis of the patient for that breast. 
   
   
       40 . The method of  claim 21 , wherein the compressive member comprises a substantially rigid plastic having relatively high acoustic transparency, the substantially rigid plastic having pre-molded contours in the form of a compressed breast, and wherein the orifice has an oblong shape with a major axis corresponding to an axillary axis of the patient for that breast. 
   
   
       41 . An ultrasound scanning apparatus, comprising:
 a reservoir casing holding a sonically conductive fluid and having a substantially rigid upper surface, said upper surface having an opening generally shaped to receive a breast of a prone patient;   a flexible membrane sealably secured across said opening, said flexible membrane having a lower surface in contact with said sonically conductive fluid and an upper surface pressing upward against the breast when the breast is extended through said opening; and   a transducer disposed within said sonically conductive fluid for imaging the breast through said flexible membrane.   
   
   
       42 . The ultrasound scanning apparatus of  claim 41 , said transducer comprising a first linear array probe, further comprising means for translating said first linear array probe within said sonically conductive fluid to obtain a first set of ultrasound slices sufficient to construct a three dimensional representation of the breast. 
   
   
       43 . The ultrasound scanning apparatus of  claim 42 , wherein said flexible membrane comprises a stretchable material that at least partially stretches while compressing upward against the breast. 
   
   
       44 . The ultrasound scanning apparatus of  claim 42 , wherein said flexible membrane comprises a non-elastic material that does not stretch while compressing upward against the breast. 
   
   
       45 . The ultrasound scanning apparatus of  claim 42 , further comprising means for maintaining said first linear array probe in floatable physical contact with said flexible membrane during said translation of said linear probe in a manner that exerts substantially negligible upward force on the breast. 
   
   
       46 . The ultrasound scanning apparatus of  claim 42 , further comprising means for offsetably maintaining said first linear array probe at least 1 cm from said flexible membrane during a majority of said linear probe translation, said first linear array probe maintaining sonic communication with said flexible membrane through said sonically conductive fluid. 
   
   
       47 . The ultrasound scanning apparatus of  claim 42 , said first linear array probe being oriented such that said first set of ultrasound slices corresponds to planes substantially perpendicular to a coronal plane. 
   
   
       48 . The ultrasound scanning apparatus of  claim 47 , said first linear array probe being oriented such that said first set of ultrasound slices also corresponds to planes substantially parallel to an axillary axis for that breast. 
   
   
       49 . The ultrasound scanning apparatus of  claim 42 , said first linear array probe being oriented such that said first set of ultrasound slices corresponds to planes at a first skewed angle, said first skewed angle being neither substantially parallel to nor substantially perpendicular to said coronal plane, whereby nipple shadow effects in said three-dimensional representation are at least partially reduced for locations underlying a nipple of the breast. 
   
   
       50 . The ultrasound scanning apparatus of  claim 49 , further comprising:
 a second linear array probe;   means for translating said second linear array probe within said sonically conductive fluid to obtain a second set of ultrasound slices for use in constructing said three dimensional representation of the breast;   means for offsetably maintaining said second linear array probe at least 1 cm from said flexible membrane during a majority of said linear probe translation, said second linear array probe maintaining sonic communication with said flexible membrane through said sonically conductive fluid, said second linear array probe being oriented such that said second set of ultrasound slices corresponds to planes at a second skewed angle, said second skewed angle being neither substantially parallel to nor substantially perpendicular to said coronal plane, said second skewed angle being substantially nonparallel to said first skewed angle, whereby nipple shadow effects in said three-dimensional representation are further reduced.   
   
   
       51 . The ultrasound scanning apparatus of  claim 42 , first linear array probe having an arcuate-trajectory translation such that said first set of ultrasound slices corresponds to planes at a multiplicity of skewed angles neither substantially parallel to nor substantially perpendicular to said coronal plane, whereby nipple shadow effects in said three-dimensional representation are at least partially reduced.