1. An magnetic resonance imaging (MRI) method comprising:
carrying out a multislice rapid spin echo sequence for least a first MRI slice and a second MRI slice of a subject;
said spin echo sequence being modified to (a) give the first MRI slice a phase history different from that of the second MRI slice by applying additional energy to the first MRI slice at a time the second MRI slice is not yet selected, (b) simultaneously refocusing the first and second MRI slices multiple times, and (c) applying free induction decay (fid) spoiling pulses to the first and second slices that differ from one simultaneous refocusing to the next; and
acquiring MRI signals from the two slices at times related to said simultaneous refocusing and processing the acquired signals into MRI slice images.
2. A method as in claim 1, in which the spoiling pulses alternate between a first type for the first slice and second type for the second slice, and said first and second types differ from each other at least in one of amplitude, width, and polarity.
3. A method as in claim 2, in which the two types differ at least in amplitude.
4. A method as in claim 2, in which the two types differ at least in polarity.
5. A method as in claim 2, in which the two types differ at least in width.
6. A method as in claim 1 in which said spoiling pulses differ to suppress stimulated echoes from each of said first and second slices that match in time primary echoes from the other one of said first and second slices.
7. A method as in claim 6 in which said spoiling pulses differ at least in amplitude from one refocusing to the next.
8. A method as in claim 6 in which said spoiling pulses differ at least in polarity from one refocusing to the next.
9. A method as in claim 1 in which said additional energy is applied to said first and second MRI slices on a read gradient axis.
10. A method as in claim 1 in which said spoiling pulses are applied on a slice select gradient axis.
11. A method as in claim 1 in which said spoiling pulses differ at least in amplitude from one refocusing to the next.
12. A method as in claim 1 in which said spoiling pulses differ at least in polarity from one refocusing to the next.
13. A method as in claim 1 in which said spoiling pulses comprise a first pair of pulses each having a first amplitude and a second pair or pulses each having a second amplitude different from the first amplitude.
14. A method as in claim 8 in which each of said pairs comprises a first pulse starting before, and a second pulse ending after, a respective refocusing.
15. A method as in claim 1 in which the order of said stimulated spin echoes from said first and second MRI slices changes after each simultaneous refocusing.
16. A method as in claim 1 in which said processing of the acquired MRI signals into image data comprises centric k-space ordering that places a center of k-space at the first of said refocusing times.
17. A method as in claim 1 in which said processing of the acquired MRI signals into image data comprises using non-averaged MRI signals.
18. A method as in claim 1 in which said sequence is a T1-weighed sequence.
19. A method as in claim 1 in which said multiple refocusing times comprise refocusing from two to five times.
20. A method as in claim 1 in which the order of said stimulated spin echoes from said first and second MRI slices changes after each simultaneous refocusing.
21. An MRI system comprising:
a source of a multislice rapid spin echo pulse sequence modified to (a) simultaneously refocus at least a first MRI slice and a second MRI slice of a subject multiple times, (b) give said first and second MRI slices different phase histories by applying a first additional energy to the first slice and a second additional energy to both slices before said simultaneous refocusing, and (c) apply free induction decay (fid) spoiling pulses that differ from one simultaneous refocusing to the next;
an MRI scanner coupled with said source to receive said pulse sequence and carry out an MRI scan of said first and second MRI slices of the subject in accordance therewith to acquire MRI signals and reconstruct image data for said slices; and
a display coupled with said scanner to display MRI slice images related to said image data.
22. An MRI system as in claim 21 in which said fid spoiling pulses differ to suppress stimulated echoes from one of said first and second MRI slices that would occur at a times matching primary echoes from the other one of said first and second MRI slices.
23. An MRI system as in claim 21 in which said source provides said sequence modified to give said different phase histories by applying said additional energy on a read gradient axis.
24. An MRI system as in claim 23 in which said source provides said sequence modified to give said different phase histories by applying a first pulse of said additional energy on a read gradient axis after a slice select pulse selecting said first slice and a second pulse of said additional energy on said gradient axis after a slice select pulse selecting said second slice.
25. An MRI system as in claim 21 in which said source provides said sequence modified to make said spoiling pulses differ from one refocusing to the next at least in amplitude.
26. An MRI system as in claim 21 in which said source provides said sequence modified to make said spoiling pulses differ from one refocusing to the next at least in polarity.
27. An MRI system as in claim 21 in which said source provides said sequence modified to make said spoiling pulses comprise a first pulse applied before, and a second pulse ending after, a respective refocusing. A method as in claim 1 in which said processing of the acquired MRI signals into image data comprises centric k-space ordering that places a center of k-space at the first of said refocusing times.
28. An MRI system as in claim 21 in which said MRI reconstructs said image data for said slices using non-averaged MRI signals.
29. An MRI system as in claim 21 in which said sequence said MRI scanner receives from said source is a T1-weighed sequence.
30. An MRI system as in claim 21 in which said multiple refocusing times comprise refocusing from two to five times.
31. An MRI system as in claim 21 in which said MRI scanner acquires said MRI signals from said first and second MRI slices in an order that changes after each simultaneous refocusing.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An apparatus that compensates for misalignment on a synchronous data bus, the apparatus comprising:
a synchronous lag receiver, configured to receive one of a plurality of radially distributed strobes and a data bit, and configured to delay registering of said data bit by a propagation time, said synchronous lag receiver comprising:
a first plurality of matched inverters, configured to generate successively delayed versions of said data bit;
a first mux, coupled to said first plurality of matched inverters, configured to receive a value on a lag bus that indicates said propagation time, and configured to select one of said successively delayed versions of said data bit that corresponds to said value; and
a bit receiver, configured to receive said one of said successively delayed versions of said data bit and one of a plurality of radially distributed strobe signals, and configured to register the state of said one of said successively delayed versions of said data bit upon assertion of said one of a plurality of radially distributed strobe signals.
2. The apparatus as recited in claim 1, wherein said one of a plurality of radially distributed strobe signals corresponds to a strobe, and wherein said strobe and said data bit are received by a corresponding device within which the apparatus is disposed and are sourced by a transmitting device.
3. The apparatus as recited in claim 2, wherein said corresponding device comprises an x86-compatible microprocessor.
4. The apparatus as recited in claim 1, further comprising:
a bit lag control element, configured to measure said propagation time beginning with assertion of a first signal and ending with assertion of a second signal, and configured to generate said value on said lag bus, said bit lag control element comprising:
delay lock control, configured to select one of a plurality of successively delayed versions of said first signal that coincides with said assertion of said second signal; and
a gray encoder, configured to gray encode said propagation time to generate said value on said lag bus.
5. The apparatus as recited in claim 4, wherein said delay lock control selects said one of a plurality of successively delayed versions of said first signal by incrementing and decrementing bus states of select inputs on a second mux, and wherein said plurality of successively delayed versions of said first signal comprises inputs to said mux.
6. The apparatus as recited in claim 4, wherein said bit lag control element further comprises:
a second plurality of matched inverters, and wherein said propagation time is expressed as a function of zero or more of said second plurality of matched inverters.
7. The apparatus as recited in claim 4, wherein said first plurality of matched inverters are replicas of said second plurality of matched inverters.
8. An apparatus that compensates for misalignment on a synchronous data bus, the apparatus comprising:
a microprocessor, comprising:
a synchronous lag receiver, configured to receive one of a plurality of radially distributed strobes and a data bit, and configured to delay registering of said data bit by a propagation time, said synchronous lag receiver comprising:
a first plurality of matched inverters, configured to generate successively delayed versions of said data bit;
a first mux, coupled to said first plurality of matched inverters, configured to receive a value on a lag bus that indicates said propagation time, and configured to select one of said successively delayed versions of said data bit that corresponds to said value; and
a bit receiver, configured to receive said one of said successively delayed versions of said data bit and one of a plurality of radially distributed strobe signals, and configured to register the state of said one of said successively delayed versions of said data bit upon assertion of said one of a plurality of radially distributed strobe signals.
9. The apparatus as recited in claim 8, wherein said one of a plurality of radially distributed strobe signals corresponds to a strobe, and wherein said strobe and said data bit are received by a corresponding device within which the apparatus is disposed and are sourced by a transmitting device.
10. The apparatus as recited in claim 9, wherein said corresponding device comprises an x86-compatible microprocessor.
11. The apparatus as recited in claim 8, further comprising:
a bit lag control element, configured to measure said propagation time beginning with assertion of a first signal and ending with assertion of a second signal, and configured to generate said value on said lag bus, said bit lag control element comprising:
delay lock control, configured to select one of a plurality of successively delayed versions of said first signal that coincides with said assertion of said second signal; and
a gray encoder, configured to gray encode said propagation time to generate said value on said lag bus.
12. The apparatus as recited in claim 11, wherein said delay lock control selects said one of a plurality of successively delayed versions of said first signal by incrementing and decrementing bus states of select inputs on a second mux, and wherein said plurality of successively delayed versions of said first signal comprises inputs to said mux.
13. The apparatus as recited in claim 11, wherein said bit lag control element further comprises:
a second plurality of matched inverters, and wherein said propagation time is expressed as a function of zero or more of said second plurality of matched inverters.
14. The apparatus as recited in claim 4, wherein said first plurality of matched inverters are replicas of said second plurality of matched inverters.
15. A method that compensates for misalignment on a synchronous data bus, the method comprising:
first receiving one of a plurality of radially distributed strobes and a data bit, and delaying registering of the data bit by a propagation time, said first receiving comprising:
first generating successively delayed versions of the data bit;
second receiving a value on a lag bus that indicates the propagation time, and first selecting one of the successively delayed versions of the data bit that corresponds to said value; and
registering the state of the one of said successively delayed versions of the data bit upon assertion of one of a plurality of radially distributed strobe signals.
16. The method as recited in claim 15, wherein the one of a plurality of radially distributed strobes signals corresponds to a strobe, and wherein the strobe and the data bit are received by a corresponding device within which the apparatus is disposed and are sourced by a transmitting device.
17. The method as recited in claim 16, wherein the corresponding device comprises an x86-compatible microprocessor.
18. The method as recited in claim 15, further comprising:
measuring the propagation time beginning with assertion of a first signal and ending with assertion of a second signal, and second generating the value on the lag bus, said measuring comprising:
second selecting one of a plurality of successively delayed versions of the first signal that coincides with the assertion of the second signal; and
gray encoding the propagation time to generate the value on the lag bus.
19. The method as recited in claim 18, wherein said second selecting comprises:
incrementing and decrementing bus states of select inputs on a mux, wherein the plurality of successively delayed versions of the first signal comprises inputs to the mux.
20. The method as recited in claim 18, wherein said measuring further comprises:
expressing the propagation time as a function of zero or more of a first plurality of matched inverters.