Transesophageal ultrasound using a narrow probe

Abstract

Transesophageal echocardiography is implemented using a miniature transversely oriented transducer that is preferably small enough to fit in a 7.5 mm diameter probe, and most preferably small enough to fit in a 5 mm diameter probe. Signal processing techniques improve the depth of penetration to the point where the complete trans-gastric short axis view of the left ventricle can be obtained, despite the fact that the transducer is so small. The reduced diameter of the probe (as compared to prior art probes) reduces risks to patients, reduces or eliminates the need for anesthesia, and permits long term direct-visualization monitoring of patients' cardiac function.

1 . A method of transesophageal ultrasound imaging, comprising the steps of:
 introducing an ultrasound transducer into an adult patient's esophagus, wherein the transducer is located in a distal end of a housing, and wherein the housing has a flexible shaft with an outer diameter of less than about 7.5 mm and the distal end has an outer diameter of less than about 7.5 mm;   manipulating the housing so that the transducer is located either in the esophagus or in the stomach of the patient in a position that permits ultrasound images of the patient's heart to be obtained;   leaving the transducer in the position for a period of time, wherein the period of time is at least one hour; and   obtaining ultrasound images of the patient's heart using the transducer.   
     
     
         2 . The method of  claim 1 , further comprising the step of displaying the images obtained in the obtaining step. 
     
     
         3 . The method of  claim 1 , wherein, in the introducing step, the transducer is introduced into the patient's esophagus via the patient's nose or mouth. 
     
     
         4 . The method of  claim 1 , wherein, in the manipulating step, the transducer is positioned so that it is located in the fundus of the patient's stomach and aimed at the left ventricle of the patient's heart. 
     
     
         5 . The method of  claim 1 , wherein the shaft has an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm. 
     
     
         6 . The method of  claim 1 , wherein the distal end has an outer diameter of about 5 mm. 
     
     
         7 . The method of  claim 1 , wherein the transducer is a transversely oriented phased-array transducer. 
     
     
         8 . The method of  claim 1 , wherein the period of time is at least two hours. 
     
     
         9 . The method of  claim 1 , wherein the period of time is at least six hours. 
     
     
         10 . The method of  claim 9 , wherein the shaft has an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm. 
     
     
         11 . The method of  claim 9 , wherein the distal end has an outer diameter of about 5 mm. 
     
     
         12 . The method of  claim 9 , wherein the transducer is a transversely oriented phased-array transducer. 
     
     
         13 . The method of  claim 9 , wherein the obtaining step comprises continuously obtaining images of the heart during the period of time. 
     
     
         14 . The method of  claim 9 , wherein the obtaining step comprises periodically obtaining images of the heart during the period of time. 
     
     
         15 . The method of  claim 9 , wherein the transducer is a transversely oriented phased-array transducer, wherein the shaft has an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm, and wherein the obtaining step comprises continuously obtaining images of the heart during the period of time. 
     
     
         16 . The method of  claim 9 , wherein the transducer is a transversely oriented phased-array transducer, wherein the shaft has an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm, and wherein the obtaining step comprises periodically obtaining images of the heart during the period of time. 
     
     
         17 . A method of transesophageal ultrasound imaging, comprising the steps of:
 introducing an ultrasound transducer into a pediatric patient's esophagus, wherein the transducer is located in a distal end of a housing, and wherein the housing has a flexible shaft with an outer diameter of between about 2.5 and 4 mm and the distal end has an outer diameter of between about 2.5 and 4 mm;   manipulating the housing so that the transducer is located either in the esophagus or in the stomach of the patient in a position that permits ultrasound images of the patient's heart to be obtained;   leaving the transducer in the position for a period of time, wherein the period of time is at least one hour; and   obtaining ultrasound images of the patient's heart using the transducer.   
     
     
         18 . The method of  claim 17 , wherein, in the manipulating step, the transducer is positioned so that it is located in the fundus of the patient's stomach and aimed at the left ventricle of the patient's heart. 
     
     
         19 . The method of  claim 17 , wherein the transducer is a transversely oriented phased-array transducer. 
     
     
         20 . The method of  claim 17 , wherein the period of time is at least two hours. 
     
     
         21 . The method of  claim 17 , wherein the period of time is at least six hours. 
     
     
         22 . The method of  claim 21 , wherein the obtaining step comprises continuously obtaining images of the heart during the period of time. 
     
     
         23 . The method of  claim 21 , wherein the obtaining step comprises periodically obtaining images of the heart during the period of time. 
     
     
         24 . The method of  claim 21 , wherein the transducer is a transversely oriented phased-array transducer. 
     
     
         25 . A method of transesophageal ultrasound imaging, comprising the steps of:
 introducing an ultrasound transducer into the esophagus of a patient;   positioning the transducer so that it is located either in the esophagus or in the stomach of the patient, with the transducer positioned and oriented to obtain ultrasound images of the patient's heart;   leaving the transducer in place for a period of time while the patient is located outside an operating room, wherein the period of time is at least one hour; and   obtaining ultrasound images of the patient's heart using the transducer.   
     
     
         26 . The method of  claim 25 , wherein, in the positioning step, the transducer is positioned so that it is located in the fundus of the patient's stomach and aimed at the left ventricle of the patient's heart. 
     
     
         27 . The method of  claim 25 , wherein the period of time is at least two hours. 
     
     
         28 . The method of  claim 25 , wherein the period of time is at least six hours. 
     
     
         29 . The method of  claim 28 , wherein the transducer is housed in the distal end of a housing, and wherein the housing has a shaft with an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm. 
     
     
         30 . The method of  claim 29 , wherein the distal end has an outer diameter of about 5 mm. 
     
     
         31 . The method of  claim 28 , wherein the transducer is a transversely oriented phased-array transducer. 
     
     
         32 . The method of  claim 28 , wherein the obtaining step comprises continuously obtaining images of the heart during the period of time. 
     
     
         33 . The method of  claim 28 , wherein the obtaining step comprises periodically obtaining images of the heart during the period of time. 
     
     
         34 . A method of transesophageal ultrasound imaging, comprising the steps of:
 introducing an ultrasound transducer into the esophagus of a patient who is not under general anesthesia;   positioning the transducer so that it is located either in the esophagus or in the stomach of the patient, in a position that permits ultrasound images of the patient's heart to be obtained;   leaving the transducer in the position for a period of time, wherein the period of time is at least one hour; and   obtaining ultrasound images of the patient's heart using the transducer.   
     
     
         35 . The method of  claim 34 , wherein the patient is not sedated. 
     
     
         36 . The method of  claim 34 , wherein the patient is not under local anesthesia. 
     
     
         37 . The method of  claim 34 , wherein the patient is not anesthetized. 
     
     
         38 . The method of  claim 34 , wherein the patient is not anesthetized or sedated. 
     
     
         39 . The method of  claim 34 , wherein the patient is not anesthetized or sedated, and wherein the patient has not been medicated with an analgesic. 
     
     
         40 . The method of  claim 34 , wherein, in the positioning step, the transducer is positioned so that it is located in the fundus of the patient's stomach and aimed at the left ventricle of the patient's heart. 
     
     
         41 . The method of  claim 34 , wherein the period of time is at least two hours. 
     
     
         42 . The method of  claim 34 , wherein the period of time is at least six hours. 
     
     
         43 . The method of  claim 42 , wherein the transducer is housed in the distal end of a housing, and wherein the housing has a shaft with an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm. 
     
     
         44 . The method of  claim 43 , wherein the distal end has an outer diameter of about 5 mm. 
     
     
         45 . The method of  claim 42 , wherein the transducer is a transversely oriented phased-array transducer. 
     
     
         46 . The method of  claim 42 , wherein the obtaining step comprises continuously obtaining images of the heart during the period of time. 
     
     
         47 . The method of  claim 42 , wherein the obtaining step comprises periodically obtaining images of the heart during the period of time. 
     
     
         48 . The method of  claim 42 , wherein the obtaining step comprises obtaining images of the complete transgastric short axis view of the heart. 
     
     
         49 . A method of transesophageal ultrasound imaging, comprising the steps of:
 introducing an ultrasound transducer into an adult patient's esophagus, wherein the transducer is located in a distal end of a housing, and wherein the housing has a flexible shaft with an outer diameter of less than about 7.5 mm and the distal end has an outer diameter of less than about 7.5 mm;   manipulating the housing so that the transducer is located in the fundus of the patient's stomach in a position that permits ultrasound images of the transgastric short axis view of the patient's heart to be obtained; and   obtaining ultrasound images of the complete transgastric short axis view of the adult patient's heart using the transducer.   
     
     
         50 . The method of  claim 49 , wherein the shaft has an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm. 
     
     
         51 . The method of  claim 49 , wherein the distal end has an outer diameter of about 5 mm. 
     
     
         52 . The method of  claim 49 , wherein the transducer is a transversely oriented phased-array transducer. 
     
     
         53 . The method of  claim 49 , wherein the transducer is a transversely oriented phased-array transducer, and wherein the shaft has an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm. 
     
     
         54 . A method of transesophageal ultrasound imaging, comprising the steps of:
 introducing an ultrasound transducer into a pediatric patient's esophagus, wherein the transducer is located in a distal end of a housing, and wherein the housing has a flexible shaft with an outer diameter of about 4 mm or less and the distal end has an outer diameter of about 4 mm or less;   manipulating the housing so that the transducer is located in the fundus of the patient's stomach in a position that permits ultrasound images of the transgastric short axis view of the patient's heart to be obtained; and   obtaining ultrasound images of the complete transgastric short axis view of the pediatric patient's heart using the transducer.   
     
     
         55 . The method of  claim 54 , wherein the shaft has an outer diameter of between about 2.5 and 4 mm and the distal end has an outer diameter of between about 2.5 and 4 mm. 
     
     
         56 . The method of  claim 54 , wherein the transducer is a transversely oriented phased-array transducer. 
     
     
         57 . The method of  claim 54 , wherein the transducer is a transversely oriented phased-array transducer, and wherein the shaft has an outer diameter of between about 2.5 and 4 mm and the distal end has an outer diameter of between about 2.5 and 4 mm. 
     
     
         58 . A method of transesophageal ultrasound imaging, comprising the steps of:
 introducing a transversely oriented phased-array ultrasound transducer into an adult patient's esophagus, wherein the transducer is located in a distal end of a housing, and wherein the housing has a flexible shaft with an outer diameter of less than about 7.5 mm and the distal end has an outer diameter of less than about 7.5 mm;   manipulating the housing so that the transducer is located either in the esophagus or in the stomach of the patient in a position that permits ultrasound images of internal anatomy of the patient to be obtained;   leaving the transducer in the position for a period of time, wherein the period of time is at least one hour; and   obtaining ultrasound images of the patient using the transducer.   
     
     
         59 . The method of  claim 58 , further comprising the step of displaying the images obtained in the obtaining step. 
     
     
         60 . The method of  claim 58 , wherein, in the introducing step, the transducer is introduced into the patient's esophagus via the patient's nose or mouth. 
     
     
         61 . The method of  claim 58 , wherein the shaft has an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm. 
     
     
         62 . The method of  claim 58 , wherein the distal end has an outer diameter of about 5 mm. 
     
     
         63 . The method of  claim 58 , wherein the period of time is at least two hours. 
     
     
         64 . The method of  claim 58 , wherein the period of time is at least six hours. 
     
     
         65 . The method of  claim 64 , wherein the shaft has an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm. 
     
     
         66 . The method of  claim 64 , wherein the distal end has an outer diameter of about 5 mm. 
     
     
         67 . The method of  claim 64 , wherein the obtaining step comprises continuously obtaining images during the period of time. 
     
     
         68 . The method of  claim 64 , wherein the obtaining step comprises periodically obtaining images during the period of time. 
     
     
         69 . A method of transesophageal ultrasound imaging, comprising the steps of:
 introducing an transversely oriented phased-array ultrasound transducer into a pediatric patient's esophagus, wherein the transducer is located in a distal end of a housing, and wherein the housing has a flexible shaft with an outer diameter of between about 2.5 and 4 mm and the distal end has an outer diameter of between about 2.5 and 4 mm;   manipulating the housing so that the transducer is located either in the esophagus or in the stomach of the patient in a position that permits ultrasound images of internal anatomy of the patient to be obtained;   leaving the transducer in the position for a period of time, wherein the period of time is at least one hour; and   obtaining ultrasound images of the patient using the transducer.   
     
     
         70 . The method of  claim 69 , wherein the period of time is at least two hours. 
     
     
         71 . The method of  claim 69 , wherein the period of time is at least six hours. 
     
     
         72 . The method of  claim 71 , wherein the obtaining step comprises continuously obtaining images during the period of time. 
     
     
         73 . The method of  claim 71 , wherein the obtaining step comprises periodically obtaining images during the period of time. 
     
     
         74 . A method of transesophageal ultrasound imaging, comprising the steps of:
 introducing a transversely oriented phased-array ultrasound transducer into the esophagus of a patient;   positioning the transducer so that it is located either in the esophagus or in the stomach of the patient, with the transducer positioned and oriented to obtain ultrasound images of internal anatomy of the patient;   leaving the transducer in place for a period of time while the patient is located outside an operating room, wherein the period of time is at least one hour; and   obtaining ultrasound images of the patient using the transducer.   
     
     
         75 . The method of  claim 74 , wherein the period of time is at least two hours. 
     
     
         76 . The method of  claim 74 , wherein the period of time is at least six hours. 
     
     
         77 . The method of  claim 76 , wherein the transducer is housed in the distal end of a housing, and wherein the housing has a shaft with an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm. 
     
     
         78 . The method of  claim 77 , wherein the distal end has an outer diameter of about 5 mm. 
     
     
         79 . The method of  claim 76 , wherein the obtaining step comprises continuously obtaining images during the period of time. 
     
     
         80 . The method of  claim 76 , wherein the obtaining step comprises periodically obtaining images during the period of time. 
     
     
         81 . A method of transesophageal ultrasound imaging, comprising the steps of:
 introducing a transversely oriented phased-array ultrasound transducer into the esophagus of a patient who is not under general anesthesia;   positioning the transducer so that it is located either in the esophagus or in the stomach of the patient, in a position that permits ultrasound images of internal anatomy of the patient to be obtained;   leaving the transducer in the position for a period of time, wherein the period of time is at least one hour; and   obtaining ultrasound images of the patient using the transducer.   
     
     
         82 . The method of  claim 81 , wherein the patient is not sedated. 
     
     
         83 . The method of  claim 81 , wherein the patient is not under local anesthesia. 
     
     
         84 . The method of  claim 81 , wherein the patient is not anesthetized. 
     
     
         85 . The method of  claim 81 , wherein the patient is not anesthetized or sedated. 
     
     
         86 . The method of  claim 81 , wherein the patient is not anesthetized or sedated, and wherein the patient has not been medicated with an analgesic. 
     
     
         87 . The method of  claim 81 , wherein the period of time is at least two hours. 
     
     
         88 . The method of  claim 81 , wherein the period of time is at least six hours. 
     
     
         89 . The method of  claim 88 , wherein the transducer is housed in the distal end of a housing, and wherein the housing has a shaft with an outer diameter of less than about 6 mm and the distal end has an outer diameter of less than about 6 mm. 
     
     
         90 . The method of  claim 89 , wherein the distal end has an outer diameter of about 5 mm. 
     
     
         91 . The method of  claim 88 , wherein the obtaining step comprises continuously obtaining images during the period of time. 
     
     
         92 . The method of  claim 88 , wherein the obtaining step comprises periodically obtaining images during the period of time.