Advanced In Vivo Heteronuclear MRS Approaches for Studying Brain Bioenergetics Driven by Mitochondria - Dynamic Brain Imaging - page 321

(A)

1 st measurement 2 nd measurement

= 2 min 17 O 2 inhalation

(B)

3

1 st measurement

2 nd measurement

2

1

0

1 2 3 4 5

Rat Number

Fig. 15.7. ( A ) Stacked plots of H 2 17 O spectra from a representative voxel of 3D 17 O
MRSI data acquired before, during and after two consecutive two-min 17 O 2 inhalations
in a rat brain. ( B ) The comparison results between two repeated CMRO 2 measurements
in five rat brains. Adapted from Zhu et al of Ref. (86) .

tion of 17 O 2 inhalation, which allows repeated CMRO 2 mea-
surements in the same subject and experimental session (see
Fig. 15.7A ). Figure 15.7B shows the excellent reproducibil-
ity of repeated CMRO 2 measurements in five rats (1st and 2nd
measured CMRO 2 values were 2.26 ± 0.18 and 2.20 ± 0.14

μ ±

0.05 between the consecu-
tive measurements) (86) . The results demonstrate the robustness
and reliability of the simplified in vivo 17 O approach for nonin-
vasively and rapidly imaging CMRO 2 repeatedly in a small brain
of rat. This capability is particularly valuable for studies aiming at
CMRO 2 changes induced by physiological or pathological pertur-
bations in which multiple measurements are required under dif-
ferent conditions (e.g., control versus stimulation for brain func-
tion study). Therefore, the combination of the simplified model
and ultrahigh field in vivo 17 O MRS may potentially provide an
alternative neuroimaging modality for studying the central role of
oxidative metabolism in brain function and neurological diseases
(55, 77) .

mol/g/min giving a ratio of 1.03

It is well documented that the basal CMRO 2 is sensitive to the
brain temperature (see (3, 102) and the references cited therein).
However, most studies reported in the literature were based on
the global CMRO 2 measurements of entire brain using the Kety-
Schmidt method (92, 93) , and were limited by the lack of spatial
information regarding regional CMRO 2 . We have conducted a

3.3.3. Demonstration of
in vivo 17 OMRS
Application for Studying
Brain Bioenergetics