US 5,050,607 A · High resolution magnetic resonance imaging of body cavities

Abstract

A magnetic resonance (MR) imaging system includes a magnet for producing a magnetic field to which a patient is subjected, a radio frequency (RF) transmitter coupled to a body coil within the magnet, an RF receiver coupled to a surface coil within the magnet and placed as close as possible to tissue being analyzed by the MR imaging system, and a computer controlled system for generating RF signals sent from the transmitter and detected by the receiver for use in producing nuclear excitation and corresponding detected induced currents in the surface coil sent to an analog-to-digital converter and then to the computer for processing into an image display of the tissue under analysis. A preferred embodiment of the invention comprises surface coil apparatus for use in analyzing tissue within a body cavity of the patient, and a preferred system for use in analyzing the tissue of the prostate gland includes an elongated hollow tube for transrectal insertion, and expandable balloon sealed to the exterior of the tube, and a loop antenna surface coil wire secured to the exterior wall of the balloon. Fluid pressure applied to the inside of the tube and then to the interior of the balloon expands the balloon and thereby expands opposite sides of the surface coil wire and holds the surface coil antenna in a spaced apart expanded position useful in serving as a means for obtaining high resolution imaging of prostatic tissue.

Claims29

Dependent claims

An MR imaging system which includes:

a magnet for producing a magnetic field to which a patient is subjected,
an RF transmitter coupled to a body coil within the magnet,
an RF receiver wherein RF signals generated by the RF transmitter are sent from the RF transmitter and detected by the RF receiver,
a surface coil apparatus for use in producing high resolution MR images of tissue within a body cavity of the patient, the surface coil apparatus comprising:
(a) support means adapted for insertion into and withdrawal from said body cavity;
(b) a flexible antenna wire mounted on the support means and having a normal position in which portions of the antenna wire are spaced apart from one another;
(c) means mounted on the support means for expanding said portions of the antenna wire apart from one another to an expanded position wherein said portions of the antenna wire are held in their expanded spaced apart relation so that the expanded position of the antenna wire can be used for detection of RF signals generated by said transmitter to produce an image of body tissues located adjacent the antenna wire;
and
(d) means for contracting said portions of the antenna wire to the normal position for use in withdrawing the supporting means and the antenna wire thereon from the body cavity;
the RF receiver being coupled to the antenna wire for detecting RF signals induced in the antenna wire;
and
processing means coupled to the RF receiver for converting the detected signals induced in the antenna wire into an MR image display of the body tissues located adjacent the antenna wire of the surface coil apparatus.

9 more elements

An MR imaging system which includes:

a magnet for producing a magnetic field to which a patient is subjected,
an RF transmitter coupled to a body coil within the magnet,
an RF receiver coupled to a surface coil apparatus within the magnet, the surface coil apparatus providing means for obtaining high resolution MR images of tissue within a body cavity of the patient, and wherein RF signals generated by the RF transmitter are sent from the RF transmitter and detected by the RF receiver, the surface coil apparatus comprising:
(a) an elongated narrow profile hollow tube adapted for insertion into and withdrawal from the body cavity;
(b) an expandable balloon sealed to the exterior of the tube, the balloon having a normal relaxed position generally matching the normal profile of the tube and an expanded position spaced apart from the outer wall of the tube;
(c) an antenna wire secured to the wall of the balloon so that portions of the antenna wire extend at least on opposite sides of the balloon wall;
and
(d) means for applying fluid pressure to the inside of the tube and then to the interior of the balloon to expand the balloon and thereby expand said opposite portions of the antenna wire apart from one another to an expanded position useful for serving as a detection coil for detecting the RF signals generated by said RF transmitter for use in producing high resolution imaging of adjacent tissue within said body cavity;
the receiver being coupled to the antenna wire for detecting the RF signals induced in the antenna wire;
and
processing means coupled to the RF receiver for converting the detected signals induced in the antenna wire into an MR image display of the tissue located within said body cavity adjacent the antenna wire.

8 more elements

Dependencies are inferred from the claim text.

High resolution magnetic resonance imaging of body cavities

Life of this patent

High resolution magnetic resonance imaging of body cavities

Life of this patent

Abstract

Claims29