Amniocentesis needle with improved sonographic visibility

Claim 2

A cannula for use in medical procedures wherein ultrasonic imaging of the cannula is achieved by directing an incident ultrasonic beam of known wavelength against the cannula, said cannula comprising: a generally tubular cannula body having a proximal end, a distal end, a generally cylindrical wall, and a hollow inner lumen extending axially therethrough; at least one generally round sounding aperture formed in said cannula wall, the diameter of said sounding aperture being approximately equal to the known wavelength of said incident ultrasonic beam.

Claim 3

The cannula of claim 1 wherein the diameter of said sounding aperture is substantially 0.44 mm so as to be substantially equal to the wavelength of an incident beam which has a wavelength of 0.44 mm.

Claim 4

The cannula of claim 1 wherein the diameter of said sounding aperture is substantially 0.15 mm so as to be substantially equal to the wavelength of an incident beam which has a wavelength of 0.15 mm.

Claim 5

The cannula of claim 1 wherein the diameter of said sounding aperture is substantially 0.21 mm so as to be substantially equal to the wavelength of an incident beam which has a wavelength of 0.21 mm.

Claim 6

The cannula of claim 1 wherein the diameter of said sounding aperture is substantially 0.26 mm so as to be substantially equal to the wavelength of an incident beam which has a wavelength of 0.26 mm.

Claim 7

The cannula of claim 1 wherein the diameter of said sounding aperture is substantially 1.54 mm so as to be substantially equal to the wavelength of an incident beam which has a wavelength of 1.54 mm.

Claim 8

The cannula of claim 1 wherein a tissue penetrating bevel is formed on the distal end thereof.

Claim 9

The cannula of claim 1 wherein a connecting hub is formed on the proximal end thereof.

Claim 10

The cannula of claim 8 wherein said connecting hub is configured to permit fluidic attachment of a syringe thereto so as to permit withdrawal of a quantity of fluid proximally through the lumen of said cannula and into said syringe.

Claim 11

The cannula of claim 1 wherein said sounding aperture(s) is located within 2 cm of the distal end of the cannula.

Claim 12

The cannula of claim 1 wherein a plurality of said sounding apertures are formed within 2 cm of the distal end of the cannula.

Claim 13

The cannula of claim 1 further comprising: a solid stylet having a proximal end, a distal end, and an outer surface, said stylet being sized and configured so as to be slidably axially disposable within the cannula lumen.

Claim 14

The cannula of claim 12 wherein said solid stylet, when fully slidably advanced into said cannula lumen, is axially coextensive therewith and resides therein such that the distal end of said solid stylet is flush with the distal end of the surrounding cannula.

Claim 15

An amniocentesis needle of improved sonographic visibility comprising: a generally tubular needle body having a proximal end, a distal end, a generally cylindrical wall, and a hollow inner lumen extending axially therethrough; a connecting hub formed on said proximal end; a tissue penetrating bevel located on the distal tip of said needle and operative to effect transabdominal penetration and intraamnionic positioning of at least the distal end of the needle; and at least one generally round sounding aperture formed in the needle wall, the diameter of said sounding aperture being substantially equal to an incident ultrasonic beam wavelength between 0.15 and 0.54 mm so as to improve the imagability of acoustical return signals which emanate from the needle wall when an incident ultrasonic beam having a wavelength substantially equal to the diameter of the diameter of said sounding apertures is directed against said needle wall.

Claim 16

An amniocentesis needle of improved sonographic visibility comprising: a generally tubular needle body having a proximal end, a distal end, a generally cylindrical wall, and a hollow inner lumen extending axially therethrough; a connecting hub formed on said proximal end; a tissue penetrating bevel located on the distal tip of said needle and operative to effect transabdominal penetration and intraamnionic positioning of at least the distal end of the needle; and at least one generally round sounding aperture formed in the needle wall, the diameter of said sounding aperture being substantially equal to an incident ultrasonic beam wavelength between 0.15 and 0.54 mm so as to improve the imagability of acoustical return signals which emanate from the needle wall when an incident ultrasonic beam having a wavelength substantially equal to the diameter of the diameter of said sounding apertures is directed against said needle wall.

Claim 17

The amniocentesis needle of claim 14 wherein the wavelength of said incident ultrasonic beam is substantially 0.44 millimeters and the corresponding diameter of said sounding aperture(s) is substantially 0.44 millimeters.

Claim 18

The amniocentesis needle of claim 14 wherein the wavelength of said incident ultrasonic beam is substantially 0.15 millimeters and the corresponding diameter of said sounding aperture(s) is substantially 0.15 millimeters.

Claim 19

The amniocentesis needle of claim 14 wherein the wavelength of said incident ultrasonic beam is substantially 0.21 millimeters and the corresponding diameter of said sounding aperture(s) is substantially 0.21 millimeters.

Claim 20

The amniocentesis needle of claim 14 wherein the wavelength of said incident ultrasonic beam is substantially 0.26 millimeters and the corresponding diameter of said sounding aperture(s) is substantially 0.26 millimeters.

Claim 21

The amniocentesis needle of claim 14 wherein the wavelength of said incident ultrasonic beam is substantially 0.68 millimeters and the corresponding diameter of said sounding aperture(s) is 0.68 substantially millimeters.

Claim 22

The amniocentesis needle of claim 14 wherein the wavelength of said incident ultrasonic beam is substantially 0.54 millimeters and the corresponding diameter of said sounding aperture(s) is substantially 0.54 millimeters.

Claim 23

The amniocentesis needle of claim 14 further comprising: a solid stylet having a proximal end, a distal end, and an outer surface, said stylet being sized and configured so as to be slidably axially disposable within the cannula lumen.

Claim 24

The cannula of claim 21 wherein said solid stylet, when fully slidably advanced into said cannula lumen, is axially coextensive therewith and resides therein such that the distal end of said solid stylet is flush with the distal end of the surrounding cannula.