The use of diffusion tensor tractography to measure the distance between the anterior tip of the Meyer loop and the temporal pole in a cohort from Southern China.
OBJECTIVE
Anterior temporal lobe resection plus amygdalohippocampectomy can cause damage to the anterior portion of the optic radiation, also known as the Meyer loop, resulting in homonymous superior quadrantanopia. Magnetic resonance diffusion tensor tractography (DTT) of the Meyer loop can help in surgical planning. In this study, the distance of the anterior tip of the Meyer loop to the temporal lobe pole (ML-TP) in the Southern Chinese population was assessed.


METHODS
The authors studied 16 Southern Chinese individuals (8 men and 8 women; mean age 45.6 years, range 21-60 years). Diffusion tensor images were obtained with a 3-T MR imaging system using a single-shot spin echo echo planar imaging sequence. Two trained operators, one neurosurgeon (Operator A) and one radiologist (Operator B), carried out the DTT analysis with software iPlan (BrainLAB) and FiberTrak (Philips).


RESULTS
For the 32 temporal lobes, the intraclass correlation coefficient (ICC) of the 2 operators' results using iPlan was 0.96, while that of Operator A using iPlan and Operator B using FiberTrak was 0.75. The ICC of Operator B using iPlan and FiberTrak was 0.81. The ML-TP distance of normal lobes (30 lobes [2 lobes that previously underwent surgery were excluded]) was 36.3±5.5 mm (range 26.6-48.9 mm), 36.3±5.3 mm (range 26.8-48.2 mm), and 35.9±6.4 mm (range 20.8-48.4 mm) for Operator A using iPlan, Operator B using iPlan, and Operator B using FiberTrak, respectively (p>0.05).


CONCLUSIONS
The 2 operators reached good agreement on ML-TP distance measurement using DTT. The DDT results can be more software dependent than operator dependent. The measurement with FiberTrak demonstrated larger range and standard deviation than measurement with iPlan.
Wang
Yi-Xiang J
YX
Department of Diagnostic Radiology and Organ Imaging, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China. yixiang_wang@cuhk.edu.hk
Zhu
Xian-Lun
XL
Deng
Min
M
Siu
Deyond Y W
DY
Leung
Jason C S
JC
Chan
Queenie
Q
Chan
Danny T M
DT
Mak
Calvin Hoi Kwan
CH
Poon
Wai S
WS
D000328:Adult; D000679:Amygdala / Q000601:surgery; D038481:Anterior Temporal Lobectomy / Q000009:adverse effects; D002681:China; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D005260:Female; D006423:Hemianopsia / Q000209:etiology / Q000517:prevention & control; D006624:Hippocampus / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009900:Optic Nerve / Q000033:anatomy & histology*; D013702:Temporal Lobe / Q000033:anatomy & histology* / Q000601:surgery; D055815:Young Adult