多层CT在显示颈深淋巴结转移灶与颈动脉间脂肪间隙中的应用

Application of MSCT in Display of Perivascular Rim of Fat between Carotid Artery and Cervical Lymph Node Metastasis

目的 探讨多层CT显示转移淋巴结与颈动脉之间脂肪间隙的优势及其在诊断二者粘连方面的临床价值。方法 对头颈部肿瘤合并颈动脉间隙淋巴结转移患者行多层CT三维容积扫描 ,使用多平面成像 (multipleplaneredering ,MPR)方法 ,在垂直于颈动脉走行的平面 ,显示淋巴结与血管之间是否存在脂肪间隙 ,并与由CVR(computedvolumeredering ,CVR)模拟的传统CT轴位像及手术结果对照分析。结果 6 9例患者的 137枚大于 1.0cm的淋巴结中 ,4 2枚在CVR像中脂肪间隙可见 ;在与颈动脉垂直MPR图像中 ,5 9枚转移淋巴结的脂肪间隙清晰可见。在CVR模拟轴位像中 ,9枚脂肪间隙可见 ,均未与颈动脉粘连 ,2 2枚脂肪间隙消失中的 15枚与颈动脉粘连。结论 多层CT可较传统CT更准确地显示脂肪间隙存在情况 ,在诊断粘连上有一定的临床应用价值。

Objective The aim of this study was to determine the value of multi-slice CT in detecting perivascular rim of fat between carotid artery and deep cervical lymph node metastasis and in diagnosis of adherence of cervical lymph node metastasis to carotid artery. Methods 69 patients with deep cervical lymph node metastasis from cancer of head and neck underwent MSCT scans, and 137 deep cervical lymph node metastasis more than one centimetre in diameter were studied. MPR images perpendicular to carotid artery were performed to display perivascular rim of fat between carotid artery and deep cervical lymph node metastasis, and compared with conventional CT axial images simulated by CVR(computed volume rendering)images and with outcomings of operation. The statistic difference was tested by Fisher's exact test. Results In 137 lymph node metastasis from 69 patients, perivascular rim of fat in 42 lymph nodes was displayed in conventional CT axial images simulated by CVR images, and in 59 lymph nodes with MSCT`s MPR images. There is statistic difference between conventional CT axial images and MPR images in displaying perivascular rim of fat(χ 2=5.72,P<0.05). 22 of 69 patients underwent opration, adherence or no-adherence was confirmed in 31 lymph node metastasis from 22 patients. The sensitivity ,specificity and accuracy rate of MPR images were 100%,75%,87% respectively in predictive diagnosis of tumor attachment, while those of conventional axial images were 100%, 56.25%, 77.42% respectively. Conclusions MSCT's MPR image is preciser than conventional CT's axial image in detecting the existence of the perivascular rim of fat and can contribute to improving the capacity of predicting lymph node metastasis adherence to carotid artery.