US5699801A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of internal magnetic resonance imaging and spectroscopic analysis and associated apparatus
Assignee: Johns Hopkins University
•
Filing: 1995-06-01
•
Granted: 1997-12-23
•
Expires: 2015-06-01
Abstract
Abstract The invention provides a method for magnetic resonance imaging and spectroscopic analysis of the interior of a specimen which includes positioning the specimen within a main magnetic field, introducing an invasive probe having an elongated receiver coil into or adjacent to the specimen with the coil having at least one pair of elongated electrical conductors, preferably, generally parallel to each other disposed within a dielectric material and having a pair of ends electrically connected to each other. RF pulses are provided to the region of interest to excite magnetic resonance signals, gradient magnetic pulses are applied to the region of interest with the receiver coil receiving magnetic resonance signals and emitting responsive output signals which may be processed by a computer to provide image information for display in a desired manner. The method in a preferred form involves employing a flexible receiver coil which has uniform sensitivity along the coil and may be operated even when the magnetic resonance signal is in an oblique position. Tuning capacitance may be distributed along the length of the coil and/or a Faraday screen provided to minimize dielectric losses between the coil and the surrounding material of the specimen. The method may be used on a wide variety of specimens and in a preferred use is introduced into small blood vessels of a patient to facilitate determination of atherosclerotic plaque. Medical intervention procedures, such as plaque removal, may be employed generally simultaneously with the imaging of the present invention. Corresponding apparatus is provided.
Inventors
- 👤 Ergin Atalar
- 👤 Paul A. Bottomley
- 👤 Elias A. Zerhouni
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:29
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/34; G01R33/34084; A; A61; A61B; A61B5/00; A61B5/05; A61B5/055; G01R33/341; G01R33/36; G01R33/3642; G01R33/3657; G01R33/3678; G01R33/34007
Claims Analysis
Total Claims: 88
Claim 1
Independent Claim
178 words
A method of internal magnetic resonance analysis of a specimen comprising positioning said specimen within a main magnetic field, introducing an invasive probe having an elongated receiver coil into said specimen, employing as said receiver coil a resiliently flexible coil having at least one pair of elongated electrical conductors disposed within a resiliently flexible dielectric material and having a pair of ends electrically connected to each other, maintaining the spacing between said pair of elongated electrical conductors substantially uniform throughout said analysis, imposing said main magnetic field on region of interest of said specimen, applying RF pulses to said region of interest to excite magnetic resonance signals within said specimen, applying gradient magnetic pulses to said region of interest to spatially encode the magnetic resonance signals, said receiver coil receiving said magnetic resonance signals and emitting responsive output signals, processing means for receiving and processing said output signals and converting them into MR information, and employing display means for receiving MR information from said processing means and displaying the same as an image or as chemical shift spectra.
Claim 2
Independent Claim
178 words
A method of internal magnetic resonance analysis of a specimen comprising positioning said specimen within a main magnetic field, introducing an invasive probe having an elongated receiver coil into said specimen, employing as said receiver coil a resiliently flexible coil having at least one pair of elongated electrical conductors disposed within a resiliently flexible dielectric material and having a pair of ends electrically connected to each other, maintaining the spacing between said pair of elongated electrical conductors substantially uniform throughout said analysis, imposing said main magnetic field on region of interest of said specimen, applying RF pulses to said region of interest to excite magnetic resonance signals within said specimen, applying gradient magnetic pulses to said region of interest to spatially encode the magnetic resonance signals, said receiver coil receiving said magnetic resonance signals and emitting responsive output signals, processing means for receiving and processing said output signals and converting them into MR information, and employing display means for receiving MR information from said processing means and displaying the same as an image or as chemical shift spectra.
Claim 3
Dependent Claim
19 words
The method of claim 1 including employing in said coil said conductors which are generally parallel to each other.
Claim 4
Dependent Claim
44 words
The method of claim 2 including including in said receiver output signals spatially localized chemical shift information, employing said processing means to convert said chemical shift information into chemical shift spectra, and employing said display means to receive and display said chemical shift spectra.
Claim 5
Dependent Claim
41 words
The method of claim 3 including employing said method in one-dimensional chemical shift imaging, wherein said chemical shift information is spatially resolved in a direction substantially along the length of said receiver coil at the region of interest in said specimen.
Claim 6
Dependent Claim
32 words
The method of claim 2 including employing said processing means to convert said receiver coil output signals into image information, and employing said display means to receive and display said image information.
Claim 7
Dependent Claim
37 words
The method of claim 2 including employing as said receiver coil a coil having a conductor length measured along the portion of said conductor thereof disposed within said dielectric material of about 2 cm to 50 cm.
Claim 8
Dependent Claim
22 words
The method of claim 6 including employing as said coil a coil having a length of about 5 cm to 20 cm.
Claim 9
Dependent Claim
23 words
The method of claim 7 including employing as said coil a coil having a maximum width of about 0.5 mm to 15 mm.
Claim 10
Dependent Claim
23 words
The method of claim 6 including employing as said coil a coil having a maximum width of about 0.5 mm to 2 cm.
Claim 11
Dependent Claim
19 words
The method of claim 6 including employing as said coil a coil having substantially uniform sensitivity along the coil.
Claim 12
Dependent Claim
21 words
The method of claim 2 including delivering said receiver coil within said probe which is a catheter, into a blood vessel.
Claim 13
Dependent Claim
24 words
The method of claim 11 including inserting said coil containing catheter within veins to image and acquire MR chemical shift information about atherosclerotic plaques.
Claim 14
Dependent Claim
18 words
The method of claim 12 including employing said method generally simultaneous with plaque removal from said blood vessel.
Claim 15
Dependent Claim
23 words
The method of claim 12 including employing as said coil a coil which remains sensitive to magnetic resonance signals even at oblique positions.
Claim 16
Dependent Claim
38 words
The method of claim 14 including said coil having the length measured along one leg thereof within said dielectric material of about 2 cm to 50 cm, and a maximum width of about 0.5 mm to 2 cm.
Claim 17
Dependent Claim
37 words
The method of claim 2 including employing as a said receiver coil a coil having two said pairs of electrical conductors embedded in a dielectric material with conductors within said pair being electrically connected to each other.
Claim 18
Dependent Claim
27 words
The method of claim 2 including employing a decoupling circuit disposed intermediate said receiver coil and said processing means to resist current induction during said RF pulses.
Claim 19
Dependent Claim
19 words
The method of claim 2 including employing a Faraday shield around said receiver coil to resist undesired dielectric losses.
Claim 20
Dependent Claim
36 words
The method of claim 18 including employing as said Faraday shield a plurality of electrically conductive ting-like elements secured to the dielectric material of said coil in relatively axially spaced position from adjacent said ting-like elements.
Claim 21
Dependent Claim
23 words
The method of claim 18 including employing as said Faraday shield a plurality of elongated electrically conductive elements secured to said dielectric material.
Claim 22
Dependent Claim
24 words
The method of claim 2 including employing said coil as an RF pulse transmitting source in addition to said employment as a receiver coil.
Claim 23
Dependent Claim
21 words
The method of claim 2 including securing said receiver coil to said invasive probe, wherein said invasive probe is an endoscope.
Claim 24
Dependent Claim
28 words
The method of claim 2 including securing said receiver coil to the exterior of said invasive probe, wherein said invasive probe is a magnetic resonance compatible biopsy needle.
Claim 25
Dependent Claim
21 words
The method of claim 2 including employing said method in vitro on a specimen which has been removed from a patient.
Claim 26
Dependent Claim
14 words
The method of claim 2 including employing said method in vivo on a patient.
Claim 27
Dependent Claim
13 words
The method of claim 25 including employing said process on a human being.
Claim 28
Dependent Claim
17 words
The method of claim 26 including employing said method in a natural opening in said human being.
Claim 29
Dependent Claim
61 words
The method of claim 2 including employing a tuning/matching circuit electrically interposed between said receiver coil and said processing means to enhance RF power transfer and MR signal-to-noise ratio from said receiver coil, and performing said analysis without adjusting said tuning/matching circuit immediately prior to probe introduction into said specimen or during the period said receiver coil is in said specimen.
Claim 30
Dependent Claim
18 words
The method of claim 28 including employing as said tuning/matching circuit a plurality of capacitors of fixed capacitance.
Claim 31
Dependent Claim
24 words
The method of claim 2 including employing a plurality of capacitors relatively spaced along said receiver coil and secured to a flexible substrate thereof.
Claim 32
Dependent Claim
15 words
The method of claim 30 including electrically connecting said capacitors to a common capacitance rail.
Claim 33
Dependent Claim
15 words
The method of claim 30 including tuning said receiver coil by altering the length thereof.
Claim 34
Dependent Claim
35 words
The method of claim 30 including establishing said plurality of capacitors by providing a plurality of relatively spaced electrically conductive elements each of which cooperate with another of said elements to function as a capacitor.
Claim 35
Dependent Claim
24 words
The method of claim 30 including creating said plurality of capacitors by etching an electrical conductor which was previously secured to a dielectric substrate.
Claim 36
Dependent Claim
14 words
The method of claim 34 including employing as said dielectric substrate a flexible material.
Claim 37
Dependent Claim
21 words
The method of claim 30 including creating said plurality of capacitors by depositing electrically conductive material on a flexible dielectric material.
Claim 38
Dependent Claim
22 words
The method of claim 2 including employing said coil in multislice imaging of said specimen without requiring movement of said receiver coil.
Claim 39
Dependent Claim
13 words
The method of claim 2 including employing computer means as said processing means.
Claim 40
Dependent Claim
26 words
The method of claim 1 including said electrical conductors in said coil being helically intertwined with each other, whereby induction of undesired eddy currents is resisted.
Claim 41
Dependent Claim
25 words
The method of claim 1 including employing a patient as said specimen, and performing generally simultaneously with said imaging a medical procedure on said patient.
Claim 42
Dependent Claim
45 words
The method of claim 1 including locating the coil position with respect to said main magnetic field by said processing means, calculating by said computer means the sensitivity map of said coil, and employing said sensitivity map to enhance the display of the acquired images.
Claim 43
Dependent Claim
165 words
Magnetic resonance specimen analysis apparatus comprising magnetic field generating means for establishing a main magnetic field on said specimen, magnetic field gradient generating means for establishing gradients in said main magnetic field, RF signal generating means for emitting pulsed RF signals to at least portions of said specimen disposed within said main magnetic field, an elongated receiver coil having at least a pair of elongated electrical conductors disposed within a dielectric material and having a pair of ends electrically connected to each other and having means for receiving signals emitted from said specimen responsive to said RF pulses and emitting responsive output signals, processing means for receiving and processing said output signals from said receiver coil and creating MR information related thereto, visual display means for displaying said MR information received from said processing means as an image or as chemical shift spectra, and probe means for positioning said receiver coil with respect to said specimen for insertion of said receiver coil into said specimen.
Claim 44
Dependent Claim
165 words
Magnetic resonance specimen analysis apparatus comprising magnetic field generating means for establishing a main magnetic field on said specimen, magnetic field gradient generating means for establishing gradients in said main magnetic field, RF signal generating means for emitting pulsed RF signals to at least portions of said specimen disposed within said main magnetic field, an elongated receiver coil having at least a pair of elongated electrical conductors disposed within a dielectric material and having a pair of ends electrically connected to each other and having means for receiving signals emitted from said specimen responsive to said RF pulses and emitting responsive output signals, processing means for receiving and processing said output signals from said receiver coil and creating MR information related thereto, visual display means for displaying said MR information received from said processing means as an image or as chemical shift spectra, and probe means for positioning said receiver coil with respect to said specimen for insertion of said receiver coil into said specimen.
Claim 45
Dependent Claim
20 words
The magnetic resonance specimen imaging apparatus of claim 42 including said pair of conductors disposed generally parallel to each other.
Claim 46
Dependent Claim
33 words
The apparatus of claim 43 including said processing means having means for converting said output signals into spatially localized chemical shift spectra, and said visual display means having means for displaying said spectra.
Claim 47
Dependent Claim
63 words
The apparatus of claim 44 including said magnetic field gradient generating means has means for generating a magnetic field gradient substantially parallel to said receiver coil over a region of interest of said specimen in order to generate one-dimensional resolved chemical shift spectra that are spatially resolved substantially along the direction of the receiver coil in a region of interest in said specimen.
Claim 48
Dependent Claim
32 words
The apparatus of claim 44 including said receiver coil having a conductor length measured along the portion of said conductor disposed within said dielectric material of about 2 cm to 50 cm.
Claim 49
Dependent Claim
19 words
The apparatus of claim 46 including said receiver coil having a length of about 5 cm to 20 cm.
Claim 50
Dependent Claim
20 words
The apparatus of claim 46 including said receiver coil having a maximum width of about 0.5 mm to 2 cm.
Claim 51
Dependent Claim
46 words
The apparatus of claim 44 including said receiver coil being secured within catheter means, said catheter means having an external diameter structured to be received within the blood vessel of a patient, and said processing means having means for imaging and spectroscopically analyzing said output signals.
Claim 52
Dependent Claim
20 words
The apparatus of claim 49 including said receiver coil having a length which facilitates multislice imaging without moving said coil.
Claim 53
Dependent Claim
25 words
The apparatus of claim 44 including said receiver coil being flexible, whereby said receiver coil may assume a tortuous path upon insertion into said specimen.
Claim 54
Dependent Claim
31 words
The apparatus of claim 44 including said receiver coil being structured to remain sensitive to magnetic resonance signals even when disposed at oblique angles with respect to the main magnetic field.
Claim 55
Dependent Claim
20 words
The apparatus of claim 52 including said receiver coil having substantially uniform sensitivity along the length of said receiver coil.
Claim 56
Dependent Claim
29 words
The apparatus of claim 44 including said receiver coil having two said pairs of electrical conductors with conductors within each of said pairs being electrically connected to each other.
Claim 57
Dependent Claim
41 words
The apparatus of claim 54 including said coil having the length measured along the portion of one conductor thereof disposed within said dielectric material of about 2 cm to 50 cm, and a diameter of about 0.5 mm to 2 cm.
Claim 58
Dependent Claim
28 words
The apparatus of claim 44 including decoupling circuit means disposed intermediate said receiver coil means and said processing means to resist undesired current induction during said RF pulses.
Claim 59
Dependent Claim
19 words
The apparatus of claim 56 including a Faraday shield disposed around said receiver coil to resist undesired dielectric losses.
Claim 60
Dependent Claim
34 words
The apparatus of claim 57 including said Faraday shield including a plurality of electrically conductive ring-like elements secured to the dielectric material of said receiver coil in relatively axially spaced position from each other.
Claim 61
Dependent Claim
21 words
The apparatus of claim 57 including said Faraday shield having a plurality of elongated conductive elements secured to said dielectric material.
Claim 62
Dependent Claim
24 words
The apparatus of claim 44 including said receiver coil means having means to function as an RF pulse transmitting source to excite MR signals.
Claim 63
Dependent Claim
21 words
The apparatus of claim 44 including said probe being an endoscope, and said receiver coil being secured to the exterior thereof.
Claim 64
Dependent Claim
28 words
The apparatus of claim 44 including said probe being a magnetic resonance compatible biopsy needle, and said receiver coil being secured to the exterior of said biopsy needle.
Claim 65
Dependent Claim
22 words
The apparatus of claim 44 including said probe being structured to be received within a naturally occurring opening in a human being.
Claim 66
Dependent Claim
28 words
The apparatus of claim 44 including a tuning/matching circuit electrically interposed between said receiver coil and said processing means for enhancing RF power transfer from said receiver coil.
Claim 67
Dependent Claim
24 words
The apparatus of claim 64 including said tuning/matching circuit having capacitor means electrically connected to said receiving coil to enhance the MR signal-to-noise ratio.
Claim 68
Dependent Claim
14 words
The apparatus of claim 65 including said tuning/matching circuit having a plurality of capacitors.
Claim 69
Dependent Claim
39 words
The apparatus of claim 44 including said receiver coil having a plurality of capacitors relatively spaced along said coil and secured to a flexible substrate, whereby the presence of said capacitors will not preclude flexing of said receiver coil.
Claim 70
Dependent Claim
17 words
The magnetic apparatus of claim 67 including said capacitors being electrically connected to a common capacitance rail.
Claim 71
Dependent Claim
15 words
The apparatus of claim 67 including said coil being tunable by adjusting the length thereof.
Claim 72
Dependent Claim
36 words
The apparatus of claim 67 including said coil having as said plurality of capacitors a plurality of relatively spaced electrically conductive elements each of which cooperate with another of said elements to function as a capacitor.
Claim 73
Dependent Claim
21 words
The apparatus of claim 67 including said capacitors having a plurality of electrically conductive elements secured to a dielectric said substrate.
Claim 74
Dependent Claim
13 words
The apparatus of claim 71 including said electrically conductive elements having etched edges.
Claim 75
Dependent Claim
20 words
The apparatus of claim 67 including said plurality of spaced capacitors having a plurality of axially spaced ring shaped capacitors.
Claim 76
Dependent Claim
28 words
The apparatus of claim 42 including said electrical conductors in said receiver coil means being helically intertwined with each other, whereby said MR response signals may be enhanced.
Claim 77
Dependent Claim
46 words
The apparatus of claim 42 including said processing means having means for locating the receiver coil position with respect to said receiver main magnetic field, calculating the sensitivity map of said coil, and means for employing said sensitivity map to enhance the display of acquired images.
Claim 78
Dependent Claim
110 words
A magnetic resonance coil assembly comprising a resiliently flexible elongated receiver coil for internal magnetic resonance analysis of a region of interest of a specimen by insertion of the receiver coil into the specimen to receive magnetic energy emitted by nuclei disposed within a specimen which is positioned within a main magnetic field responsive to bursts of radio frequency energy and gradient magnetic pulses which are both applied to the specimen and emitting responsive signals, and said receiver coil having at least one pair of elongated electrically connected conductors disposed within a flexible dielectric material and having means for receiving signals emitted from a specimen and emitting responsive output signals.
Claim 79
Dependent Claim
110 words
A magnetic resonance coil assembly comprising a resiliently flexible elongated receiver coil for internal magnetic resonance analysis of a region of interest of a specimen by insertion of the receiver coil into the specimen to receive magnetic energy emitted by nuclei disposed within a specimen which is positioned within a main magnetic field responsive to bursts of radio frequency energy and gradient magnetic pulses which are both applied to the specimen and emitting responsive signals, and said receiver coil having at least one pair of elongated electrically connected conductors disposed within a flexible dielectric material and having means for receiving signals emitted from a specimen and emitting responsive output signals.
Claim 80
Dependent Claim
25 words
The coil assembly of claim 76 including said coil having a plurality of capacitors spaced along said coil and secured to a flexible substrate thereof.
Claim 81
Dependent Claim
16 words
The coil assembly of claim 77 including said coil being tunable by adjusting the length thereof.
Claim 82
Dependent Claim
37 words
The coil assembly of claim 77 including said coil having as said plurality of capacitors a plurality of relatively spaced electrically conductive elements each of which cooperate with another of said elements to function as a capacitor.
Claim 83
Dependent Claim
21 words
The coil assembly of claim 77 including said capacitors having a plurality of electrically conductive elements secured to a dielectric substrate.
Claim 84
Dependent Claim
14 words
The coil assembly of claim 80 including said electrically conductive elements having etched edges.
Claim 85
Dependent Claim
21 words
The coil assembly of claim 77 including said plurality of spaced capacitors having a plurality of axially spaced ring shaped capacitors.
Claim 86
Dependent Claim
34 words
The coil assembly of claim 77 including said coil having a length disposed within said dielectric material of about 2 cm to 50 cm, and a maximum width of about 0.5 to 2 cm.
Claim 87
Dependent Claim
25 words
The coil assembly of claim 77 including said coil assembly having a fixed capacitance tuning/matching circuit operatively associated thereof electrically connected to said elongated conductors.
Claim 88
Dependent Claim
16 words
The coil assembly of claim 84 including a decoupling circuit operatively associated with said tuning/matching circuit.
References Cited (Backward Citations)
US4932411A
Cited
US4672972A
Cited
US5170789A
Cited
US4766381A
Cited
EP0469035A1
Cited
US5293872A
Cited
US5271400A
Cited
US5307808A
Cited
US5473251A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-22 | 2001-06-23 | 2001-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-22 | 2005-06-23 | 2005-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-22 | 2009-06-23 | 2009-12-23 | $7700.00 | Window Closed / Lapsed |