Chao Wu1, Bin Zhao1, Guangbin Wang1, Shanshan Wang1, and Hongjing Bao1
1Shandong Medical Imaging Research Institute, Shandong university, Jinan, China, People's Republic of
Synopsis
This study aimed to measure the FA and ADC values by quantitative DTI at the tibial nerve and common peroneal nerve and
determine whether DTI can be used in the DPN. 25 healthy volunteers and 13 patients with DPN were underwent MR examinations at 3T
including DTI of knee. The FA values of both tibial nerve and common peroneal
nerve in DPN patients were significantly lower than those in
healthy volunteers. The ADC values in DPN patients were higher than those
in healthy groups. DTI may thus be a reliable method to added diagnostic value in patients with DPN.Purpose
Diabetic peripheral neuropathy (DPN) is one of the
most common complications of diabetes mellitus (DM), with a high incidence, and
greatly affecting patients’ quality of life. Diffusion tensor imaging (DTI) is
a noninvasive imaging modality to evaluate the neuronal tract structure in
vivo. It develops rapidly and is already widely employed in research. DTI is
increasingly being utilized to investigate peripheral nerve integrity. DTI
allows the quantification of fractional anisotropy (FA) and apparent diffusion
coefficient (ADC). This study aimed to measure the fractional anisotropy (FA)
and apparent diffusion coefficient (ADC) values by quantitative diffusion
tensor imaging (DTI) at the tibial nerve and common peroneal nerve and
determine whether DTI can be used in the diagnosis of diabetic peripheral
neuropathy (DPN).
Methods
The local ethics institutional review board approved the implemented
study protocol. All patients and healthy volunteers were studied after informed
consent was obtained. 25 healthy volunteers and 13 patients with diabetic peripheral
neuropathy (DPN) were enrolled to undergo MR examinations at 3.0T including DTI
of knee. All subjects were examined using a commercially
available clinical 3-T MRI system (Achieva TX, Philips Healthcare). The
patients were validated by correlation with clinical and electrophysiology. The
patients and controls are sex and age matched. Magnetic resonance neurography was performed using transverse
T2-weighted imaging, axial T2-weighted spectral adiabatic inversion recovery
(SPAIR) imaging, axial or coronal T1-weighted imaging and DTI. The imaging
parameters for axial or coronal 2D T1-weighted imaging examination were:
TR/TE=550/20ms; slice thickness=3.0mm;
overlap, 0.3-0.5mm;
FOV=130×130mm²; number of
slices=45; sensitivity-encoding factor=6; and number of signals acquired=2;
image matrix=312×260; acquisition time=03:34.5s. The parameters
for axial 2D T2-weighted spectral adiabatic inversion recovery (SPAIR, Philips
Healthcare) imaging were: TR/TE=3000/55ms; slice thickness=3.0mm; overlap=0.3-0.5mm; FOV=130×130mm²;
number of slices=45; sensitivity-encoding factor=6; and number of signals
acquired=1; image matrix: 236×169; acquisition time: 03:36s. The
diffusion-weighted imaging examination was performed using the following
parameters: TR/TE=14034/94ms; image matrix=128×125；FOV=160×160mm²;
overlap=0; slice thickness=3.0mm;
b-value=800s/mm²; flip angle=90deg; sensitivity-encoding factor=2.5; number of
signals acquired=2; number of slices=100; acquisition plane: axial;
multitransmit=no; half-fourier factor=no; acquisition time: 08:15.3s. FA and
ADC values of the tibial nerve and common peroneal nerve were computed from
nerve regions of interest co-registered. The Student’s t-test was used to
quantitatively assess differences between DPN patients and healthy volunteers.
Results
Figure
1 presents the tibial nerve and common peroneal nerve FA and ADC values of
volunteers in our study. Figure 2 shows the tibial nerve and common peroneal nerve FA and ADC values of
DPN patients. The FA values of both tibial nerve and common peroneal nerve in DPN
patients (0.52±0.04) were significantly lower than those in healthy volunteers
(0.67±0.17) (P＜0.05). The ADC values in DPN patients
(1.44±0.06) were higher than those in healthy groups (1.16±0.04) (P＜0.05).
Discussion
There is very
little data on the comparability and reproducibility of quantitative peripheral
nerve diffusion tensor imaging (DTI) parameters when measured. Meaningful
comparisons of DTI parameters, thus, critically depend on exact repeated
identification of anatomical location and placement of regions-of-interest
[1].
Although significant FA and ADC differences among normal and pathologic
conditions of peripheral nerves have been reported, age related changes should
be taken into account, as they may hypothetically impact the pathological
thresholds for both FA and ADC
[2]. In the nerve conduction study on the
patient group, no action potential was evoked in one patient whose tibial nerve
FA values were very low.
Conclusion
DTI obtained on
a 3.0T clinical MRI scanner can demonstrate early abnormal changes following
DPN to tibial nerve and common peroneal nerve. The FA and ADC values for DPN
are consistent with the pathological and functional changes. DTI may thus be a
reliable method to provide useful information and added diagnostic value in
patients with DPN.
Acknowledgements
First and foremost, I would like to acknowledge and extend my heartfelt gratitude to my teacher,for his vital encouragement and patient guidance, generous assistance and invaluable advice,all of which have been of inestimable worth to the completion of my thesis. And Iwould also like to thank all the teachers and friends who have given me generous support andhelpful advice during the past years of my study. They have provided me great help andcomprehensive supervision. I have benefited a great deal from their advice and suggestions.References
[1] Guggenberger R,
Nanz D, Puippe G, et al. Diffusion tensor imaging of the median nerve: intra-,
inter-reader agreement, and agreement between two software packages. Skeletal
Radiology 2012;41(8):971–80.
[2] Stein D, Neufeld
A, Pasternak O, et al. Diffusion tensor imaging of the median nerve in healthy
and carpal tunnel syndrome subjects. Journal of Magnetic Resonance Imaging
2009;29(3):657–62.