CN105686828A

CN105686828A - A noninvasive dynamic muscle oxygen uptake rate measuring method based on magnetic resonance imaging

Info

Publication number: CN105686828A
Application number: CN201510577095.8A
Authority: CN
Inventors: 王成彦; 张锐; 王鹤; 金立新; 王霄英; 张珏; 方竞
Original assignee: Peking University
Current assignee: Peking University
Priority date: 2015-09-13
Filing date: 2015-09-13
Publication date: 2016-06-22

Abstract

The invention provides a method of estimating the distribution diagram of the dynamic oxygen uptake rates of whole muscular tissue by using the imaging results of noninvasive quantitative dynamic magnetic resonance R2' and the results of the oxygen uptake rates of superficial muscle tissue measured by an NIRS. The method comprises the step of firstly, dynamically obtaining the R2' distribution diagram of the whole muscle tissue according to an improved multiple-echo asymmetrical spin echo (ps MASE) sequence of pulses periodically moving for 180 degrees and a moving window estimation (ME) strategy; secondly, obtaining the %HbO2 change curve of superficial muscles by using the NIRS and performing sampling to the time resolution the same as that of dynamic R2' measurement; thirdly, fitting the R2' and the %HbO2 via a secondary empirical equation and calculating the dynamic 1-%HbO2 change process of the whole diagram via a coefficient obtained after fitting.

Description

A kind of method of the noinvasive kinetic measurement muscle oxygen uptake rate based on nuclear magnetic resonance

Technical field

The invention belongs to Functional magnetic resonance imaging field, specifically one combines lower limb Brief Ischemic Preconditioning model and the dynamic R2 ' of magnetic resonance measures technology, and by an empirical relation, R2 ' performance graph does the method that calibration noinvasive dynamically obtains muscle oxygen uptake rate variation diagram。

Background technology

The noinvasive oxygen consumption of skeletal muscle and metabolic measurements have very important application in a lot of fields。The technology of a kind of accurate, repeatable and noninvasive quantitative skeletal muscle oxygen consumption is scientific research and the focus of clinical workers concern, and will play highly important effect in myonosus physiological function research and diagnosis。

At present, a lot of image modes have been used to muscle oxygen consumption quantitatively in。Typically, the transcutaneous oxygen pressure method based on the electrode technology improved has been widely used in the ischemia diagnosis of lower limb superficial tissue。But this technology is subject to the restriction of the detection degree of depth, is only able to detect the blood capillary of skin, thus the oxygen metabolism situation of muscle can only be reflected indirectly。Recently, near infrared tissue BOLD contrast (NIRS) technology and positron emission tomography (PET) technology are also all used to measure the oxygen consumption of local skeletal muscle。But, NIRS is similarly subjected to the restriction of penetration depth, and PET uses widely because it has radiation and fancy price also limit。Nuclear magnetic resonance (MRI) technology do not limit with its penetration depth, have very big advantage in muscle oxygen metabolism imaging without the advantage of ionizing radiation and high spatial resolution。Ogawa et al. introduces Blood oxygen level-dependent technology (BOLD) the earliest, provides for non-invasive measurement hemodynamics and is likely to。Occur uneven owing to HbO2 Oxyhemoglobin deoxidation result in local and then cause magnetic susceptibility to change, thus shortening relaxation time T2*。BOLD technology utilizes the magnetic susceptibility change that this deoxyhemoglobin causes to obtain imaging contrast just。Carefully seeing Magnetic field inhomogeneity due to what magnetic susceptibility effect caused, result in magnetic resonance signal has signal attenuation faster on the basis of T2* relaxation, and the size of this magnetic susceptibility is by tissue-specific, it is possible to provide different spatial contrast。At present, BOLD technology has been used to the skeletal muscle function imaging under multiple-task, including ischemia-reperfusion task, motor task and micro-tapping task dispatching。But, traditional the more of BOLD technology perfusion are to observe change qualitatively, and cannot provide quantitative information, it is therefore necessary to make improvements。

Blood oxygen saturation (%HbO₂) it is the important indicator of response organization's physiological feature, this point is particularly critical in skeletal muscle, because the oxygen supply of skeletal muscle and to consume be highly couple。It is known that paramagnetic deoxyhemoglobin can cause local magnetic field uneven, thus accelerating T2* decay。There are some researchs in the correction being T2* and the NIRS that gtadient echo (GRE) sequence the obtains %HbO2 obtained before。But it practice, R2 ' has better specificity on evaluation tissue oxygen metabolism, because R2 ' eliminates the interference of R2 in R2*。Elder et al. employs an empirical relation and obtains the %HbO of tissue from the R2 ' correction that magnetic resonance obtains₂, the result obtained is fine with NIRS measurement result dependency。But there are some defects in their method, in the process obtain R2 ', such as employ independent twice scanning respectively obtain T2 and T2*, this can cause being subject to measuring an impact for the many factors such as physiological change and motion in the process calculating R2 ', Elder et al. only obtains the %HbO2 average of a partial musculature on the other hand, and obtains whole muscle oxygen uptake rate (1-%HbO₂) map information often more need。Being subject to the inspiration of this work, we make use of a kind of method of better quick kinetic measurement R2 ', and the parameter after simultaneously using correction obtains the oxygen uptake rate scattergram of full figure。

Summary of the invention

The present invention proposes one and combines lower limb Brief Ischemic Preconditioning model and the dynamic R2 ' of magnetic resonance measures technology, and by an empirical relation, R2 ' performance graph does the method that calibration noinvasive dynamically obtains muscle oxygen uptake rate variation diagram。

At present except NIRS, it does not have other method can dynamically obtain the oxygen of tissue and absorb parameter by noinvasive。But, NIRS can only provide the overall valuation of specific region tissue, and can not provide a scattergram, and the information so obtained just lacks spatial resolution natively。On the other hand, NIRS is additionally subjected to the restriction of penetration depth, it is impossible to measure the oxygen metabolism situation of deep part muscle。Considering MRI clear superiority in room and time resolution, this patent wishes to combine above two method, reaches dynamically to obtain the purpose of muscle oxygen uptake rate scattergram。

In this patent, we utilize many echoes asymmetric spin echo (psMASE) sequence that the periodicity of a kind of improvement moves 180 ° of pulses to estimate, in conjunction with Moving Window, the method (psMASE-ME) that (ME) is tactful, R2 ' can be obtained quickly and accurately, and temporal resolution can reach the 1-5 second。Because R2 ' eliminates the interference of R2, R2 ' has better specificity on evaluation tissue oxygen metabolism, so in this patent, we utilize R2 ' with the NIRS %HbO obtained₂Calibrate。After obtaining dynamic R2 ' data, we use the method for quadratic fit by local Δ R2 ' and %HbO based on empirical equation₂Correct, and obtain the Dynamic Oxygen uptake ratio (1-%HbO of muscle full figure further with this correction relationship formula₂) information。Whole handling process is as shown in Figure 1。

In research muscle oxygen uptake rate change procedure, we utilize NIRS to measure lower limb shallow table muscle %HbO in ischemia model₂, and data are done a degree of smooth, as shown in Fig. 1 step 2。This ischemia task is to apply sphygmomanometer cuff by side, muscle upper end, and to keep pressure be that 50-300mmHg obtains, as shown in Fig. 1 step 1。Utilize the R2 ' data that psMASE-ME method dynamically obtains in ischemic period with the temporal resolution of 1-5 second simultaneously, data are done a degree of smooth, as shown in Fig. 1 step 3。When hemostasis, for the measurement difference reducing individual variation and different time measurement causes, utilize the dynamic R2 ' average R2 ' value deducting under quiescent condition to obtain relative variation Δ R2 ' and do curve matching。1-HbO₂The secondary relation of % and Δ R2 ' is built upon shallow table muscle average result in whole ischemic period。These data carry out least square fitting according to below equation, as shown in Fig. 1 step 4。

[1]

Finally we by matched curve in conjunction with psASE-ME method measurement to the Δ R2 ' value (as Suo Shi Fig. 1 step 5) of whole muscle obtain the HbO of muscle full figure₂% result, as shown in Fig. 1 step 6。

According to foregoing, this patent measures technology and correction function by introducing quick R2 ', it is achieved that the oxygen uptake rate situation of change of lower limb muscles in Continuous Observation hemostasis-situation。

Accompanying drawing explanation

Fig. 1 is noinvasive kinetic measurement muscle oxygen uptake rate changing method flow chart。

Fig. 2 is Δ R2 ', the 1-%HbO that shallow table gastrocnemius kinetic measurement obtains₂And to the 1-%HbO that Δ R2 ' quadratic fit obtains₂Curve。

Fig. 3 is the Δ R2 ' that deep musculus soleus kinetic measurement obtains and the 1-%HbO utilizing fit correlation to calculate R2 '₂Curve。

Detailed description of the invention

Following primary minimum leg muscle is example, and in nuclear magnetic resonance process, experimenter faces upward and lies low on MR is scanning bed, uses inflation sphygmomanometer cuff to tie up at right lower limb thigh place, uses nylon tape to fix and prevents sphygmomanometer cuff from relaxing。In scanning process, keep the head of experimenter, foot and knee in same level。PsMASE sequence scanning should scan laggard row in the scanning of routine location and reference image, and a suitable psMASE sequential parameter can be provided that fieldofview (FOV)=150 × 150mm²,matrixsize=70×70,repetitiontime(TR)=2000ms,TE₁/TE₂/TE₃/TE₄=60/80/100/120ms, echospace=20ms, τ=-10/0/10ms, slicethickness=6mm, SENSEfactor=2, NSA=1, echoshiftnumber=12。Experimenter maintains quiescent condition 10 minutes, and then sphygmomanometer cuff is manually inflated to 200mmHg pressure by us, and whole gas replenishment process completed in 5 seconds, and maintained 90 seconds。On the other hand, we use the oxygen metabolism situation of multiple spectra NIRS apparatus measures lower limb。For each volunteer's magnetic resonance and near-infrared measuring same lower limb, the hemostasis condition of applying is the same when scanning with MR, to ensure twice to reach identical task status。The result that NIRS instrument obtains passes through absorption and scattering coefficienth, and the computation rule carried that dispatches from the factory according to instrument obtains the 1-HbO of lower limb₂%。Δ R2 ', the 1-%HbO that shallow table gastrocnemius kinetic measurement obtains₂And based on the 1-%HbO that Δ R2 ' quadratic fit is obtained by the secondary empirical relation determined therebetween₂Curve is as in figure 2 it is shown, based on the empirical relation determined by shallow table muscle and the dynamic Δ R2 ' of deep musculus soleus, the 1-%HbO of the deep musculus soleus of release that are obtained by psASE-ME₂Curve is as shown in Figure 3。

Claims

1. the method based on the noinvasive kinetic measurement muscle oxygen uptake rate of nuclear magnetic resonance, it is characterized in that, dynamic R2 ' Parameter Map is obtained by functional mri, oxygen uptake rate parameter with muscular tissue, and based on the empirical relation existed between oxygen uptake rate and the R2 ' of muscular tissue, estimate the DYNAMIC DISTRIBUTION figure of the oxygen uptake rate of whole muscular tissue。

2. a kind of noinvasive kinetic measurement muscle oxygen uptake rate method based on nuclear magnetic resonance according to claim 1, it is characterised in that imaging uses special asymmetric spin echo (ASE) sequence, obtains the image of scanning。

3. a kind of noinvasive kinetic measurement muscle oxygen uptake rate method based on nuclear magnetic resonance according to claim 1, it is characterized in that, use the oxygen uptake rate parameter including the apparatus measures tissues such as near infrared tissue BOLD contrast (NIRS), transcutaneous oxygen pressure instrument。

4. a kind of noinvasive kinetic measurement muscle oxygen uptake rate method based on nuclear magnetic resonance according to claim 1, it is characterised in that the empirical relation empirical relation of use is non-linear relation。

5. a kind of noinvasive kinetic measurement muscle oxygen uptake rate method based on nuclear magnetic resonance according to claim 1, it is characterised in that image tissue can be upper arm, lower limb, abdominal muscles, muscle of back etc.。

6. a kind of noinvasive kinetic measurement muscle oxygen uptake rate method based on nuclear magnetic resonance according to claim 1, it is characterised in that the method obtaining tissue R2 ' value is one piece of area-of-interest (ROI) of selection from magnetic resonance image (MRI)。

7. a kind of noinvasive kinetic measurement muscle oxygen uptake rate method based on nuclear magnetic resonance according to claim 1, it is characterised in that the method obtaining tissue R2 ' value is selection Products for Cooked Whole Muscle tissue from magnetic resonance image (MRI)。

8. a kind of noinvasive kinetic measurement muscle oxygen uptake rate method based on nuclear magnetic resonance according to claim 1, it is characterised in that in scanning process, the upstream section gathering image is applied pressure, unclamp after continuing for some time。

9. a kind of noinvasive kinetic measurement muscle oxygen uptake rate method based on nuclear magnetic resonance according to claim 2, it is characterised in that imaging can be Single Slice Mode or multilamellar scans simultaneously。

10. a kind of noinvasive kinetic measurement muscle oxygen uptake rate method based on nuclear magnetic resonance according to claim 2, it is characterised in that obtain R2 ' Parameter Map by the method for least square fitting。