Apparatuses for positioning within an internal channel

Abstract

Methods and apparatuses for positioning medical devices onto (or close to) a desired portion of the interior wall of an internal channel, such as for scan imaging, for photodynamic therapy and/or for optical temperature measurement. In one embodiment, a catheter assembly has a distal portion that can be changed from a configuration suitable for traversing the internal channel to another configuration suitable for scan at least a spiral section of the interior wall of an internal channel, such as an artery. In one example, the distal portion spirals into gentle contact with (or close to) a spiral section of the artery wall for Optical Coherence Tomography (OCT) scanning. The spiral radius may be changed through the use of a guidewire, a tendon, a spiral balloon, a tube, or other ways.

What is claimed is: 
     
         1 . An elongated assembly, comprising:
 a proximal portion; and   a distal portion, the distal portion to be inserted into a blood vessel, the distal portion controllable through the proximal portion, the distal portion comprising:
 an elongated sheath, the elongated sheath housing a core capable of emitting an optical beam for imaging, the core movable along the sheath; 
 a guide structure coupled with the elongated sheath, the guide structure being controllable through the proximal portion to increase an overall diameter of the distal portion from a first overall diameter of a first configuration to a second overall diameter of a second configuration, in the second configuration the elongated sheath having a substantially spiral shape having a plurality of spirals, the sheath being made of a material that is substantially transparent or translucent on an outside of the spirals, wherein the guide structure, through lateral movement in a lumen of the elongated sheath, cause the sheath to take the spiral shape; and 
   a control mechanism to facilitate movement of the core through the spirals while imaging, wherein the spiral shape has a pre-shaped spiral radius having a pitch length of the spirals that is selected to be less than ten times a known radius of the vessel.   
     
     
         2 . The assembly of  claim 1 , wherein the core is capable of projecting light through the material and into a portion of the vessel and receiving light from the portion of the vessel and through the material sufficiently to use the received light to form an image of an image depth of a vessel wall or vulnerable plaque at the portion of the vessel. 
     
     
         3 . The assembly of  claim 2 , wherein the image depth one of comprises a thickness of two millimeters of tissue of the vessel wall, or is sufficient to identify the presence of a diseased region on the vessel wall. 
     
     
         4 . The assembly of  claim 1 , wherein one of (1) the distal portion has a pre-shaped spiral shape that includes the pre-shaped spiral radius having the pitch length and the guide structure is a stiff guidewire with a straight shape; or (2) the distal portion has a straight shape and the guidewire has a stiff pre-shaped spiral shape that includes the pre-shaped spiral radius having the pitch length. 
     
     
         5 . The assembly of  claim 1 , further comprising one of a guide wire, a balloon, a tube, or a tendon controllable through the proximal portion to increase an overall diameter of the distal portion from the first overall diameter to the second overall diameter. 
     
     
         6 . The assembly of  claim 1 , wherein a pitch length of the spiral shape and an imaging depth of the core are sufficient to identify vulnerable plaque on the blood vessel. 
     
     
         7 . The assembly of  claim 1 , wherein, when the elongated sheath is in the substantially spiral shape:
 movement of the core along the elongated sheath does not change the substantially spiral shape of the elongated sheath; and   the core is capable to scan the vessel along a spiral path on the vessel.   
     
     
         8 . The assembly of  claim 1 , wherein the pitch length of the spiral shape is one of less than five times an imaging depth of the core, or less than a size of a significant vulnerable plaque on a blood vessel plus two times an imaging depth of the core. 
     
     
         9 . The assembly of  claim 1 , wherein in the second configuration a diameter of the spiral shape is substantially equal to a diameter of the vessel. 
     
     
         10 . The assembly of  claim 1 , wherein the distal portion has a stiffness to be of a spiral shape in absence of external constrains; wherein a straight guidewire is insertable into the distal portion to straighten the distal portion into the first configuration, and wherein the straight guidewire is insertable into the elongated sheath in the distal portion to straighten the distal portion into the first configuration. 
     
     
         11 . An assembly, comprising:
 a sheath having a spiral shape having a plurality of spirals to be disposed along a blood vessel, the sheath being made of a material that is substantially transparent or translucent on an outside of the spiral, the sheath housing a core capable of at least one of: projecting an optical beam onto a portion of the vessel and receiving a light from a portion of the vessel, the core being movable along the sheath to scan at least a spiral portion of the vessel, wherein the guide structure, through lateral movement in a lumen of the elongated sheath, cause the sheath to take the spiral shape; and   a control mechanism to facilitate movement of the core through the spirals while imaging, wherein the spiral shape has a pre-shaped spiral radius having a pitch length of the spirals that is selected to be less than ten times a known radius of the vessel.   
     
     
         12 . The assembly of  claim 11 , wherein the sheath has a guide member lumen; and a diameter of the spiral shape is substantially equal to the diameter of the vessel, and wherein the sheath is capable of being straightened in the vessel when a guide member is inserted into the guide member lumen. 
     
     
         13 . The assembly of  claim 11 , wherein the core is capable of projecting light through the material and into a portion of the vessel and receiving light from the portion of the vessel and through the material sufficiently to use the received light to form an image of an image depth of a vessel wall or vulnerable plaque at the portion of the vessel. 
     
     
         14 . The assembly of  claim 13 , wherein the image depth one of comprises a thickness of two millimeters of tissue of the vessel wall, or is sufficient to identify the presence of a diseased region on the vessel wall. 
     
     
         15 . The assembly of  claim 11 , wherein one of (1) the distal portion has a pre-shaped spiral shape that includes the pre-shaped spiral radius having the pitch length and the guide structure is a stiff guidewire with a straight shape; or (2) the distal portion has a straight shape and the guidewire has a stiff pre-shaped spiral shape that includes the pre-shaped spiral radius having the pitch length. 
     
     
         16 . An assembly to be inserted into a blood vessel, the assembly comprising:
 a sheath, the sheath housing a core capable of at least one of: projecting an optical beam onto a portion of the vessel and receiving a light from the portion of the vessel, the core being movable along the sheath to scan at least a portion of a vessel, the sheath having a plurality of spirals, the sheath being made of a material that is substantially transparent or translucent on an outside of the spiral;   a support coupled to at least a portion of the sheath, the support capable of changing shape to clear or reduce at least a portion of a signal path between the sheath and the vessel, wherein the guide structure, through lateral movement in a lumen of the elongated sheath, cause the sheath to take the spiral shape; and   a control mechanism to facilitate movement of the core through the spirals while imaging, wherein the spiral shape has a pre-shaped spiral radius having a pitch length of the spirals that is selected to be less than ten times a known radius of the vessel.   
     
     
         17 . The assembly of  claim 16 , wherein one of the core is to receive a light for an optical temperature measurement of the vessel, the core is to project a beam for a photodynamic therapy to the vessel, or the core is to project a beam onto the vessel and receive a reflected light for Optical Coherence Tomography (OCT) scanning. 
     
     
         18 . An elongated assembly, comprising:
 a proximal portion; and   a distal portion, the distal portion to be inserted into a blood vessel, the distal portion controllable through the proximal portion, the distal portion comprising:
 an elongated sheath, the elongated sheath housing a core capable of emitting an optical beam for imaging, the core movable along the sheath; and 
 a guide structure coupled with the elongated sheath, the guide structure being controllable through the proximal portion to increase an overall diameter of the distal portion from a first overall diameter of a first configuration to a second overall diameter of a second configuration, in the second configuration the elongated sheath having a substantially spiral shape having a plurality of spirals, wherein the core is housed within the elongated sheath, the core to project an optical beam and to receive a reflected light for optical coherence tomography; and wherein the core is movable along the elongated sheath to scan a portion of the vessel, wherein the spiral shape has a pre-shaped spiral radius having a pitch length of the spirals that is selected to be less than ten times a known radius of the vessel. 
   
     
     
         19 . The assembly of  claim 18 , wherein the sheath is made of a material that is substantially transparent or translucent on an outside of the spirals, and wherein the guide structure, through lateral movement in a lumen of the elongated sheath, cause the sheath to take the spiral shape. 
     
     
         20 . The assembly of  claim 18 , wherein one of (1) the distal portion has a pre-shaped spiral shape that includes the pre-shaped spiral radius having the pitch length and the guide structure is a stiff guidewire with a straight shape; or (2) the distal portion has a straight shape and the guidewire has a stiff pre-shaped spiral shape that includes the pre-shaped spiral radius having the pitch length.