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US5363844A
Expired / Lapsed
US
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Breath-hold monitor for MR imaging
Assignee: Mayo Clinic in Florida
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Filing: 1993-08-13
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Granted: 1994-11-15
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Expires: 2013-08-13
Abstract
Abstract In an NMR system a respiration monitor provides a visual feedback to the patient which enables the patient to perform a series of breath-holds with the patient's diaphragm positioned at the same reference point. This enables NMR data to be acquired over a series of breath-holds without introducing blurring or image artifacts. Between breath-holds a navigator pulse sequence is used to gather NMR data from which diaphragm position is measured, and during each breath-hold the pulse sequence is changed to gather NMR image data.
Inventors
- 👤 Stephen J. Riederer
- 👤 Yu L. Liu
- 👤 Richard L. Ehman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:17
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G01R33/567; G01R33/5676; G01R33/28
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
117 words
In an NMR system for performing an image scan in which a series of NMR imaging pulse sequences are executed to acquire a corresponding series of NMR signals from which an image of a patient is reconstructed, the improvement comprising: a respiration monitor for producing a respiration signal indicative of the position of the patient's diaphragm during patient respiration; feedback means for receiving the respiration signal and providing the patient with an indication which enables the patient to initiate a breath-hold at a diaphragm reference position; and means for producing a respiration trigger signal after the patient initiates a breath-hold near the diaphragm reference position to enable the execution of NMR imaging pulse sequences during the breath-hold.
Claim 2
Dependent Claim
117 words
In an NMR system for performing an image scan in which a series of NMR imaging pulse sequences are executed to acquire a corresponding series of NMR signals from which an image of a patient is reconstructed, the improvement comprising: a respiration monitor for producing a respiration signal indicative of the position of the patient's diaphragm during patient respiration; feedback means for receiving the respiration signal and providing the patient with an indication which enables the patient to initiate a breath-hold at a diaphragm reference position; and means for producing a respiration trigger signal after the patient initiates a breath-hold near the diaphragm reference position to enable the execution of NMR imaging pulse sequences during the breath-hold.
Claim 3
Dependent Claim
50 words
The improvement as recited in claim 1 in which the means for producing a respiration trigger signal receives the respiration signal, and when that received respiration signal indicates the diaphragm of the patient is at the diaphragm reference position for a preset time interval, the respiration trigger signal is produced.
Claim 4
Dependent Claim
29 words
The improvement as recited in claim 1 in which the feedback means includes a display and the patient is provided a visual indication of diaphragm position on the display.
Claim 5
Dependent Claim
23 words
The improvement as recited in claim 3 in which the display includes a series of lights which indicate diaphragm position by their illumination.
Claim 6
Dependent Claim
61 words
The improvement as recited in claim 1 in which the respiration monitor includes: means for acquiring NMR navigator data from a region in the patient which includes the patient's diaphragm; means for processing the acquired NMR navigator data to locate the position of the patient's diaphragm; and wherein the respiration signal is produced by repeatedly acquiring and processing NMR navigator data.
Claim 7
Dependent Claim
37 words
The improvement as recited in claim 5 in which the means for acquiring NMR navigator data produces a two-dimensional rf excitation field pulse which excites a column of spins in the patient that transects the patient's diaphragm.
Claim 8
Dependent Claim
57 words
The improvement as recited in claim 5 in which the means for processing the acquired NMR navigator data includes: means for Fourier transforming the acquired NMR navigator data; means for filtering the Fourier transformed NMR navigator data; and means for detecting an inflection in the filtered NMR navigator data which indicates the position of the patient's diaphragm.
Claim 9
Independent Claim
124 words
A method for acquiring image data from a patient by performing a series of NMR image pulse sequences, the steps comprising: a) monitoring the respiration of the patient; b) displaying to the patient an indication that a breath-hold can be achieved at a reference position of the patient's diaphragm; c) detecting that the patient has achieved a breath-hold near the reference position of the patient's diaphragm for a time interval; d) performing NMR image pulse sequences during a data acquisition interval after the patient has achieved a breath-hold near the reference position; e) displaying to the patient an indication that the breath-hold should be maintained during the data acquisition interval; and f) repeating steps a) through e) until all the image data is acquired.
Claim 10
Independent Claim
124 words
A method for acquiring image data from a patient by performing a series of NMR image pulse sequences, the steps comprising: a) monitoring the respiration of the patient; b) displaying to the patient an indication that a breath-hold can be achieved at a reference position of the patient's diaphragm; c) detecting that the patient has achieved a breath-hold near the reference position of the patient's diaphragm for a time interval; d) performing NMR image pulse sequences during a data acquisition interval after the patient has achieved a breath-hold near the reference position; e) displaying to the patient an indication that the breath-hold should be maintained during the data acquisition interval; and f) repeating steps a) through e) until all the image data is acquired.
Claim 11
Dependent Claim
57 words
The method as recited in claim 8 in which step a) is performed by: a1) performing an NMR navigator pulse sequence in which NMR navigator data is acquired from a region in the patient that includes the patient's diaphragm; and a2) processing the NMR navigator data to produce an indication of the position of the patient's diaphragm.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-11-14 | 1998-05-16 | 1998-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-11-14 | 2002-05-16 | 2002-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-11-14 | 2006-05-16 | 2006-11-15 | $7700.00 | Window Closed / Lapsed |