Article Figures & Data
Figures
- Fig 1.
A, DESS sequence timing diagram. The DESS sequence samples 2 types of signals: One FID (FISP) echo is sampled immediately after each radio-frequency pulse, while the remaining transverse magnetization is refocused just before the next excitation pulse to form a spin-echo (PSIF) signal intensity. B, The signal intensity of the DESS sequence is simulated as a function of an FA from 20° to 90° for the assumed area (T1 = 0–1500 ms and T2 = 0–1500 ms, with an interval of 10 ms, 150 × 150 points). C, The factor of contrast between gray and white matter is simulated as a function of FAs from 10° to 90°. D, With the average of gray/white matter (T1 = 800 ms, T2 = 90 ms) as the reference substance, the factors of several fluid contrasts are simulated as a function of FAs from 10° to 90° for DESS (blue lines) and conventional SSFP (red lines) sequences.
- Fig 2.
Note that both SI and SD of the parotid ducts are higher than those of the facial nerves, but there is no obvious difference between both structures for SNR and CNR.
- Fig 3.
Oblique-sagittal coronal MPR (A and B) and MIP (C and D) images of the intraparotid facial nerve demonstrate its cervicofacial division (long arrows) and small branches (short arrows). The cervicofacial division separates the deep and superficial lobes of the parotid gland.
- Fig 4.
A, The axial source image shows a curved reconstruction plane (long curved line), which is behind the retromandibular vein, following the main course of the facial nerve and parotid duct. B, The curved MPR reconstructed image shows the main trunk of the facial nerve (thick arrow) and the bifurcation of the temporofacial (crossed arrow) and the cervicofacial (thin arrow) divisions, which is posterior and inferior to the retromandibular vein (curved arrow). The course of the parotid duct (arrowheads) from the hilus of the gland to the mouth is shown. C, Diagram illustrates 1 pattern of the intraparotid facial nerve branching.
- Fig 5.
A and B, Axial MIP image (A) and source image (B) show the facial nerve (long arrow) and retromandibular vein (curved arrow). In the MIP image, more information concerning the branches of the parotid duct (short arrow) and lymph node (crossed arrow) is demonstrated, and the length of the facial nerve is shown to be longer than that in the source image. C and D, Sagittal MIP image (C) and axial source image (D) show that the parotid duct (long arrows) is in the anterior and inferior portion of the gland. In the sagittal MIP image, the branches of the parotid duct (short arrow) and lymph nodes (crossed arrow) are shown.
Tables
CNR SNR SI SD Facial nerve (n = 36) 7.7 ± 4.0 12.7 ± 4.2 91.2 ± 15.2 7.9 ± 2.5 Parotid duct (n = 24) 6.6 ± 3.4 11.5 ± 3.1 127.1 ± 51.2 11.6 ± 4.9 P value (ANOVA)b .266 (1.261) .258 (1.305) 0 (16.366) 0 (15.211) P value (paired t test)b .144 (1.514) .144 (1.514) 0 (−4.232) .001 (−3.882) a Data are presented as mean ± SD.
b ANOVA and paired t test, with data in parentheses, are F and t values, respectively. Parotid ducts (24 bilateral), which could be identified, were tested with ipsilateral facial nerves.
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