ABSTRACT
Objective To survey the apparent diffusion coefficient (ADC) value and fractional anisotropy (FA) value ofpontine cistern section of the trigeminal nerve, and understand the characteristics of various parameters of trigeminal nerve pontine cistern section. Methods The distances from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mm of brain stem in 50 healthy volunteers were recorded, and fusion images of magnetic resonance diffusion tensor imaging (DTI) with B-TFE or THRIVE were achieved to improve the spatial resolution of the pontine cistern section of the trifacial nerve; their ADC value and FA value were recorded, separately. Tracing image formation was noted in the pontine cistern section of the trigeminal or trifacial nerve. Results The ADC and FA results of the left side and right flank of pontine cistern section of the trifacial nerve in these healthy volunteers were not statistically different (P＜0.05). The closer to the brain stem, the more asymmetrical tendency of distance from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mm of brain stem between both sides. DTI indicated that the ADC values between each 2 distances from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mum of brain stem between both sides were significantly different: the ADC values increased along with the distance elevating gradually, but rotated suddenly at the line of 6-9 mm. The FA value increased in 0-6 mm along with the distance reducing gradually, and the neighboring 2 distances had remarkably statistical difference, but the FA value no longer obviously changed from the line of 6-9 mm. Conclusion DTI can distinguish the two-sided trigeminal nerve brain pond section clearly, and may realize each item of DTI. Regular changes are noted in FA and ADC values along with the different distances from pontine cistern section of the trifacial nerve to 0, 3, 6 and 9 mm of brain stem,indicating that DTI enjoys perspective in being clear about the discrimination of cranial nerve CNS section, the change-over portion and the PNS section, and in detecting the cranial nerve vascular compression.
ABSTRACT
<p><b>OBJECTIVE</b>To study the anatomy of the facial artery using 16-slice spiral CT angiography (CTA).</p><p><b>METHODS</b>Forty-five patients without vascular pathologies or other anomalies underwent 16-slice spiral CT angiography after injection of 350 mg I/ml Omnipaque through the ulnar vein. MIP and volume rendering of the images were performed to analyze the left and right facial artery.</p><p><b>RESULTS</b>The left facial artery arose from the external carotid artery with the distances from the carotid artery bifurcation of 4.5-47.90 mm (mean 18.77-/+8.98 mm), and in 1 case (2.2%), the artery arose from the common carotid artery. The right facial artery arose from the external carotid artery in all the 45 cases (100%) with distances from the carotid artery bifurcation of 6.8-39.70 mm (mean 19.23-/+8.25 mm). The bilateral facial arteries more commonly arose from the external carotid artery independently, and the lingual artery and facial artery sharing the same trunk arising from the external carotid artery was less common. In 1 case, the left facial artery and the submental artery shared the same trunk, and in another case, the left facial artery, thyroid artery and lingual artery shared the same trunk. The diameter of the left facial artery ranged from 1.40 to 4.70 mm (mean 2.83-/+0.77 mm), and that of the right facial artery was 1.60-4.30 mm (mean 2.81-/+0.79 mm). The left facial artery ended below the angle of the mouth in 12 cases (26.67%), between the angle of the mouth and the nasal wing in 7 cases (15.56%), and above the nasal wing in 26 cases (57.77%). The right facial artery ended below the angle of the mouth in 7 cases (15.56%), between the angle of the mouth and the nasal wing in 12 cases (26.67%), and above the nasal wing in 26 cases (57.77%). The bilateral facial arteries frequently passed through the submandibular gland parenchyma (23 cases on the left and 24 cases on the right), and the facial arteries were found occasionally to run below the submandibular gland (11 cases on the left and 9 on the right).</p><p><b>CONCLUSION</b>16-slice spiral CT angiography can help in preoperative facial artery evaluation noninvasively. This modality can clearly display the bilateral facial arteries, including their origin, course, distribution and ending to provide detailed information for flap designing before plastic surgery and for preoperative evaluation for microvascular surgery.</p>