Repeatability of a dual gradient‐recalled echo MRI method for monitoring post‐isometric contraction blood volume and oxygenation changes

Sánchez, Otto A.; Louie, Elizabeth A.; Copenhaver, Elizabeth A.; Damon, Bruce M.

doi:10.1002/nbm.1388

Cited by 10 publications

(17 citation statements)

References 41 publications

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“…In young muscle, Sanchez et al, previously showed good reliability, based on ICC, for peak AC BOLD responses under similar conditions (TR/TE=1000/46ms, 10s MVC), but not for TTP (33). The reliability of peak and TTP BOLD response in older adults was excellent for AC and SOL.…”

Section: Discussionmentioning

confidence: 96%

Age Reduces Microvascular Function in the Leg Independent of Physical Activity

Tonson

Noble

Meyer

et al. 2017

Medicine &Amp; Science in Sports &Amp; Exercise

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The microvasculature is critical in the control of blood flow. Aging and reduced physical activity may both decrease microvascular function. Purpose The primary aim was to evaluate the influence of age on microvascular function in adults with similar physical activity levels (PA). Secondary aims were to assess the reliability of muscle functional MRI in older adults and the relationship between physical activity and microvascular function in older adults. Methods Microvascular BOLD responses were measured in young adults (YA, n=12, 21±1 (±SD) years old, PA=239±73×103 counts/day) and older adults (OA, n=12, 64±4 years old, PA=203±48×103 counts/day). Functional MR images (3T, echo planar blood-oxygen-level dependent (BOLD)), of the leg were acquired following brief (1s) maximal voluntary isometric contractions. Test-retest reliability of BOLD responses and the Pearson correlation between peak BOLD and PA was assessed in a group of older adults (OA-r) with a broad range of PA (66±5 years old, n=9, PA range = 54×103 count/day to 674×103 counts/day). Results Peak BOLD microvascular responses were reduced for OA compared to YA. OA peak BOLD was 27% lower in the soleus (OA: 3.3±0.8% vs. YA: 4.5±1.4% YA, p=0.017) and 40% lower in the anterior compartment (1.6±0.6% OA vs. 2.7±1.1% YA, p=0.006). Coefficient of variation was 8.6% and 11.8% for peak BOLD in the soleus and anterior compartment, respectively, with an intraclass correlation of 0.950 for both muscle regions. The correlation between peak BOLD and PA was r ≥ 0.715, p ≤ 0.030. Conclusions Aging was associated with reduced microvascular function in leg muscles, independent of physical activity. The findings also revealed good reliability for BOLD MRI in older adults for the soleus and anterior compartment muscles.

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Section: Discussionmentioning

confidence: 96%

Age Reduces Microvascular Function in the Leg Independent of Physical Activity

Tonson

Noble

Meyer

et al. 2017

Medicine &Amp; Science in Sports &Amp; Exercise

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“…At each TE, the mean functional image SI for the ROI was calculated as a function of time and divided by the corresponding mean precontraction SI value. An average SI time course from each TE was obtained by averaging the SI time course from the four trials from each intensity (SI 6 and SI46), as previously described (56). The averaged SI time course was fitted to a polynomial function, and inflections in the derivative of this polynomial were used to identify the minimum and maximum postcontraction SI values.…”

Section: Subjectsmentioning

confidence: 99%

“…Building on these studies, we have used a dual-gradientrecalled echo (GRE) MRI sequence to study blood volume (V B ) and oxyhemoglobin saturation (%HbO 2 ) changes in small vessels of the muscle tissue bed following isometric contractions noninvasively, and with high temporal resolution (1 s) (13) and sufficient repeatability (56). This method consists of measuring the MRI signal intensity (SI) at two echo times (TE): 6 and 46 ms.…”

mentioning

confidence: 99%

“…This method consists of measuring the MRI signal intensity (SI) at two echo times (TE): 6 and 46 ms. Following an isometric contraction, there are transient rises in the TE ϭ 6 and 46 ms SI values (SI 6 and SI 46 , respectively); we characterize these changes with the (maximum postcontraction SI) Ϫ (minimum postcontraction SI) difference (⌬SI) (56). While postcontraction V B and %HbO 2 changes contribute to the SI changes at each TE (13,62), the predominant determinants of ⌬SI 6 and ⌬SI 46 are V B and %HbO 2 , respectively (13).…”

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confidence: 99%

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Postmaximal contraction blood volume responses are blunted in obese and type 2 diabetic subjects in a muscle-specific manner

Sánchez¹,

Copenhaver²,

Chance³

et al. 2011

American Journal of Physiology-Heart and Circulatory Physiology

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The purpose of this study was to determine whether there are differences in postisometric contraction blood volume and oxygenation responses among groups of type 2 diabetes mellitus (T2DM), obese, and lean individuals detectable using MRI. Eight T2DM patients were individually matched by age, sex, and race to non-T2DM individuals with similar body mass index (obese) and lean subjects. Functional MRI was performed using a dual-gradient-recalled echo, echo-planar imaging sequence with a repetition time of 1 s and at two echo times (TE = 6 and 46 ms). Data were acquired before, during, and after 10-s isometric dorsiflexion contractions performed at 50 and 100% of maximal voluntary contraction (MVC) force. MRI signal intensity (SI) changes from the tibialis anterior and extensor digitorum longus muscles were plotted as functions of time for each TE. From each time course, the difference between the minimum and the maximum postcontraction SI (ΔSI) were determined for TE = 6 ms (ΔSI(6)) and TE = 46 ms (ΔSI(46)), reflecting variations in blood volume and oxyhemoglobin saturation, respectively. Following 50% MVC contractions, the mean postcontraction ΔSI(6) values were similar in the three groups. Following MVC only, and in the EDL muscle only, T2DM and obese participants had ∼56% lower ΔSI(6) than the lean individuals. Also following MVC only, the ΔSI(46) response in the EDL was lower in T2DM subjects than in lean individuals. These data suggest that skeletal muscle small vessel impairment occurs in T2DM and body mass index-matched subjects, in muscle-specific and contraction intensity-dependent manners.

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“…The average SI of the three regions-of-interest was measured as a function of time in the functional images and the weighted average was calculated (Figure 1D). Each postcontractile transient was fitted to a ninth order polynomial using MATLAB’s polyfit function, similar to the procedure described in Reference (23). The peak signal was obtained from the line of best fit and the time-to-peak signal was determined by identifying the inflection in the derivative of the line of best fit.…”

Section: Methodsmentioning

confidence: 99%

Post‐contractile BOLD contrast in skeletal muscle at 7 T reveals inter‐individual heterogeneity in the physiological responses to muscle contraction

et al. 2016

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Muscle blood oxygenation-level dependent (BOLD) contrast is greater in magnitude and potentially more influenced by extravascular BOLD mechanisms at 7 T than it is at lower field strengths. Muscle BOLD imaging of muscle contractions at 7 T could, therefore, provide greater or different contrast than at 3 T. The purpose of this study was to evaluate the feasibility of using BOLD imaging at 7 T to assess the physiological responses to in vivo muscle contractions. Thirteen subjects (four females) performed a series of isometric contractions of the calf muscles while being scanned in a Philips Achieva 7 T human imager. Following 2 s maximal isometric plantarflexion contractions, BOLD signal transients ranging from 0.3 to 7.0% of the pre-contraction signal intensity were observed in the soleus muscle. We observed considerable inter-subject variability in both the magnitude and time course of the muscle BOLD signal. A subset of subjects (n = 7) repeated the contraction protocol at two different repetition times (T : 1000 and 2500 ms) to determine the potential of T -related inflow effects on the magnitude of the post-contractile BOLD response. Consistent with previous reports, there was no difference in the magnitude of the responses for the two T values (3.8 ± 0.9 versus 4.0 ± 0.6% for T = 1000 and 2500 ms, respectively; mean ± standard error). These results demonstrate that studies of the muscle BOLD responses to contractions are feasible at 7 T. Compared with studies at lower field strengths, post-contractile 7 T muscle BOLD contrast may afford greater insight into microvascular function and dysfunction.

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Repeatability of a dual gradient‐recalled echo MRI method for monitoring post‐isometric contraction blood volume and oxygenation changes

Cited by 10 publications

References 41 publications

Age Reduces Microvascular Function in the Leg Independent of Physical Activity

Age Reduces Microvascular Function in the Leg Independent of Physical Activity

Postmaximal contraction blood volume responses are blunted in obese and type 2 diabetic subjects in a muscle-specific manner

Post‐contractile BOLD contrast in skeletal muscle at 7 T reveals inter‐individual heterogeneity in the physiological responses to muscle contraction

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