Diffusion-weighted MRI of denervated muscle: a clinical and experimental study.
OBJECTIVE
The aim of this study was to investigate skeletal muscle denervation using diffusion-weighted magnetic resonance imaging (DWMRI).


METHODS
Sciatic nerve axotomy was performed in a group of nine New Zealand White rabbits, and electromyographic (EMG), pathological, and DWMRI studies were conducted on ipsilateral hamstring muscles 1 and 8 days after axotomy. In addition, DWMRI studies were carried out on leg muscles of ten patients with acute and subacute lumbosacral radiculopathy.


RESULTS
High intensity signals on short tau inversion recovery (STIR) magnetic resonance imaging and an increased apparent diffusion coefficient (ADC) were observed in denervated muscles of the animals 1 and 8 days after axotomy as well as in denervated muscles of the patients with radiculopathy. In the clinical study, ADC was 1.26 +/- 0.18 x 10(-9) m(2)/s in normal muscle and increased to 1.56 +/- 0.23 x 10(-9) m(2)/s in denervated muscles (p = 0.0016). In animals, EMG and muscle pathological studies were normal 1 day after axotomy, and the muscles demonstrated spontaneous activity on EMG and neurogenic atrophy on histological studies 7 days later.


CONCLUSIONS
This DWMRI study demonstrates that enlargement of extracellular fluid space in muscle denervation is an early phenomenon occurring several days before the appearance of EMG and histological abnormalities.
Holl
Nathalie
N
Service de Radiologie 2, Hôpitaux Universitaires de Strasbourg, Avenue Molière, 67098, Strasbourg, France.
Echaniz-Laguna
Andoni
A
Bierry
Guillaume
G
Mohr
Michel
M
Loeffler
Jean-Philippe
JP
Moser
Thomas
T
Dietemann
Jean-Louis
JL
Kremer
Stéphane
S
D000328:Adult; D000818:Animals; D001706:Biopsy; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004576:Electromyography / Q000379:methods; D045604:Extracellular Fluid; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007866:Leg / Q000294:innervation; D008161:Lumbosacral Region / Q000473:pathology; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D023421:Models, Animal; D009121:Muscle Denervation; D018482:Muscle, Skeletal / Q000294:innervation* / Q000473:pathology*; D015588:Observer Variation; D009942:Organometallic Compounds; D011817:Rabbits; D011843:Radiculopathy / Q000473:pathology*; D012584:Sciatic Nerve
D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine