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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.
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Objective To study the vascular compression on the ponline cistern of the trigeminal with magnetic resonance diffusion tensor imaging (DTI) and explore the clinical application value of DTI.Methods Sixty patients who were conformed by operation as having trigeminal neuralgia (TN) caused by responsible vascular compression (TN group) and 50 healthy volunteers (control group) were performed conventional MRI and horizontal DTI to measure the apparent diffusion coefficient (ADC)value and fractional anisotropy (FA) value. Results The ADC value and FA value of trigeminal nerve in control group were (1.76±0.98)×10-3 mm2/s, and (0.40±18), respectively, no significant differences of the ADC value and FA value between the left and right trigeminal nerves were found (P>0.05). The ADC and FA values of the trigeminal nerve among the controls, patients with mild or severe compression and the patients with compression combined with neuratrophia were statistically difrerent(P<0.05). The ADC value in the oppression region was increased in 28 patients and unchanged in 4; the average ADC value in the NT group was significantly higher than that in the control group. FA value in the oppression region decreased in 15 patients, unchanged in11 and increased in 5; the average FA value in the NT group was lower than that in the control group. Conclusion DTI has its value in determining the vascular compression of the trigeminal nerve; the greater the degree of trigeminal nerve compression is, the higher the ADC value and the lower the FA value are.
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Objective To analyze the normal anatomy of petrosal vein and the space adjacent relationship between the petrosal vein and the homolateral trigeminal nerve by balanced turbo field echo (B-TFE) Cine-MR imaging and enhanced T1 high-resolution isotropic volume excitation (e-THRIVE)imaging.Methods Forty-one patients with facial spasm and epileptiform neuralgia were selected and taken a scan with ACHIEVA NOVA DUAL A-serial 1.5T MR machine using the BTFE and e-THRIVE series.The space adjacent relationship between the petrosal vein and the trigeminal nerve in cerebellopontine angle were observed.Results The 82 sides of petrosal veins and homolateral trigeminal nerves (41 cases) were displayed well.Petrosal veins were located in cavitas subarachnoidealis,partly in free state; the number of trunk ofpetrosal vein could be 1,2,3,respectively,responding to 70 (86%),10 (12%),2 (2%).The petrosal veins located in the dorsal-lateral of trigeminal nerve were found in 74 sides (37 cases,91%,by BTFE,e-THRIVE series),the petrosal veins located in the ventri-lateral of trigeminal nerve in 6 sides (3 cases,7%,by e-THRIVE series),and the petrosal veins located in the right upon trigeminal nerve in 2 sides (1 cases,2%,by BTFE series).Conclusion B-TFE MR imaging and e-THR/VE imaging,showing the petrosal veins and trigeminal nerves clearly and evaluating their relationship accurately,can provide information of topographic anatomy before microsurgical vascular decompression.
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<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>