Diffusion tensor tractography in the head-and-neck region using a clinical 3-T MR scanner.
OBJECTIVE
Diffusion tensor tractography (DTT) for neural fibers of the head-and-neck region at 3T has not been reported. The purpose of this study was to evaluate the feasibility of using DTT for visualizing neural fibers in the head-and-neck region at 3T and to explore the use of this method in patients with head-and-neck mass lesions.


METHODS
Using a 3T scanner, we obtained magnetic resonance images of the head and neck region in 5 healthy volunteers and 5 patients with head and neck mass lesions. All subjects underwent anatomic T1-weighted and diffusion-tensor imaging using a sequence with six motion-probing gradient orientations, a b value of 800 second/mm(2), and a 128 x 128 pixel matrix. Fiber tracking was with the continuous tracking method. Different postprocessing parameters were investigated to optimize fiber density detection and minimize noise. In five patients with head-and-neck mass lesions, comparison of tractography results and operative findings with regards to mass and nerve relationship was also performed by two observers.


RESULTS
Using the two regions-of-interest method, the greatest fiber density of presumed inferior alveolar nerves was depicted at a maximum angle of 40 degrees and a minimum fiber length of 10 mm. DTT was successfully depicted in all 5 patients. In 4 patients, the relationship between DTT and operative findings was coincided or similar. The interobserver agreement was good.


CONCLUSIONS
DTT of the neural fibers in the head and neck region is feasible using a clinical 3T magnetic resonance scanner. Data from a small number of patients with head-and-neck lesions show good agreement between tractography and operative results.
Department of Diagnostic Radiology, Kumamoto University Graduate School of Medical Sciences, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
Masuma
M
Akter
Toshinori
T
Hirai
Ryosei
R
Minoda
Ryuji
R
Murakami
Shutaro
S
Saiki
Tomoyuki
T
Okuaki
Mika
M
Kitajima
Hirofumi
H
Fukuoka
Akira
A
Sasao
Shinichiro
S
Nishimura
Eiji
E
Yumoto
Kazuo
K
Awai
Yasuyuki
Y
Yamashita
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006258:Head and Neck Neoplasms / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D010525:Peripheral Nerves / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity