Objective To investigate the depiction rate of normal cisterna chyli and thoracic duct by nonenhanced MR lymphography and to describe their appearances on MR imaging. Methods Special MR hydrography sequence was added to the MR imaging protocols of 112 patients undergoing MR examination of the thorax and upper abdomen. MR imaging sequences included: ①Respiratory-gated HASTE T2W sequence; ②Breath-hold FLASH T1W sequence; ③Respiratory-gated TSE 3D T2W sequence (3D MR hydrography sequence) in coronal plane. One hundred cases who met the inclusion criteria were included into the study for observation of the depiction rate, location and morphology of cisterna chyli and thoracic duct. Results On TSE 3D T2W imaging： ①Cisterna chyli was visualized in 71/100 (depiction rate 71.0%), morphologically including single-tube type 43.7% (31/71), bifurcation type (2-3 tubes) 23.9% (17/71), plexus type 32.4% (23/71). Average length of the cisterna chyli was 4.5 cm. ②The depiction rate of the lower segment of thoracic duct was 57.0% (57/100), average ductal diameter was 0.23 cm. ③The depiction rate of upper segment of the thoracic duct was 31.0% (31/100). Conclusion As a noninvasive method for depicting the lymphatic system, nonenhaced MR lymphography (TSE 3D T2W sequence) demonstrated a high depiction rate for cisterna chyli and lower thoracic duct. Combined with axial images of HASTE and FLASH sequences, the location and morphology of these larger lymphatic ducts can be defined.
【摘要】 目的 探討伽瑪刀治療三叉神經痛MRI定位的最佳掃描序列。 方法 選擇2004年7月-2006年3月行伽瑪刀手術的原發性三叉神經痛患者60例，隨機分為3組，每組各20例。伽瑪刀術前上頭架定位，然后對3組分別采用快速自旋回波序列（Turbo Spin Echo，TSE）、增強三維小角度激發快速梯度回波序列（enhanced three-dimensiunal fast low angle shot，enhanced 3D-FLASH）、三維結構干涉穩態序列（three-dimensional constructive interference in steady state，3D-CISS）進行掃描，觀察三叉神經及周圍血管的顯示情況。 結果 ①TSE掃描20例三叉神經，14例顯示優，血管顯示一般。②增強3D-FLASH掃描三叉神經，18例顯示優，2例顯示良，周圍血管顯示優。③3D-CISS掃描三叉神經，20例均顯示優，周圍血管顯示良。 結論 3D-CISS和增強3D-FLASH序列的融合影像能夠清晰地顯示三叉神經根及周圍血管，有利于伽瑪刀的精確定位，具有較高的臨床應用價值，可以作為伽瑪刀治療原發性三叉神經痛的常規定位方法。【Abstract】 Objective To evaluate the optimal MRI localization sequences of gamma knife radiosurgery for trigeminal neuralgia. Methods From July 2004 to March 2006, sixty patients with primary trigeminal neuralgia were divided into three groups, using MR Turbo Spin Echo ( TSE), enhanced three-dimensiunal fast low angle shot 3D-FLASH and three-dimensional constructive interference in steady state ( 3D-CISS) sequence for stereotactic localization, respectively. The trigeminal nerve and surrounding vessels were observed. Results Only 14 trigeminal nerves were precisely displayed by MR TSE sequence, while 20 by 3D-CISS and 18 by 3D-FLASH. The display of surrounding vessels was excellent, good, and general by 3D-FLASH, 3D-CISS, and MR TSE, respectively. Conclusion 3D-CISS and enhanced 3D-FLASH fusion image can help achieve accurate orientation of gamma knife, which provides clear images of the trigeminal nerve and the surrounding vessels. Therefore it is of high value in clinical application, which can be used as the conventional localization method for gamma knife radiosurgery in the treatment of primary trigeminal neuralgia.
