Crecco M, Vidiri A, Angelone M L, Palma O, Morello R
Service of Radiology and Image Diagnostics, Regina Elena Cancer Institute, Rome, Italy.
Eur J Radiol. 1999 Dec;32(3):182-8. doi: 10.1016/s0720-048x(99)00017-0.
The aim of this study was to evaluate the diagnostic accuracy of magnetic resonance (MR) images to establish both the T stage and the relationships between the tumors and the surrounding structures in retromolar trigone tumors. Twenty-two patients with squamous cell carcinoma of the retromolar trigone were examined by MR with a superconductive scanner operating at 1.5T. The study was performed with spin-echo (SE) T1 and T2 and short SE T1 sequences (TR 180 ms, TE 15 ms) after the administration of 0.2 mmol/kg of gadolinium-DTPA (Gd-DTPA). The mandible was studied with SE T1 weighted sequences and GE sequences. The results were compared with the pathological data on the T stage (TNM classification) and the involvement of the surrounding structures. A positive correlation was found in 19 of the 22 patients with an accuracy of 86%. In one patient, the lesion was classified as T1 by MR which, at surgery, resulted being T4, given the infiltration of the cortical mandible (this infiltration was too limited). In another, the MR showed a T4 lesion because of the presence of low signal intensity in the mandibular marrow with enhancement after the Gd-DTPA injection without cortical erosion, while pathological data revealed a T2 lesion (this signal intensity was secondary to inflammation). In another case, the lesion was classified as T1 by MR which, at surgery, proved to be a T2 lesion. In assessing the involvement of the surrounding structures. MR showed a high accuracy, specificity and sensitivity (> 90%). Five false positive cases were observed: in two because of infiltration of the masseter muscle and in the other three, because of infiltration to the pterigoid muscle, mandible and tonsillar bed, respectively, due to the close contact between the tumors and the surrounding structures. Only one false negative case was observed with infiltration of the mandibular marrow. In evaluating the low signal intensity of the mandibular marrow, the accuracy of MR was 87% the specificity 77% and the sensitivity 100%. In one case, perineural spread along the mandibular nerve was found. In conclusion, MR proved to be highly accurate to study the T stage and examine the relationships between the surrounding structures in cases of retromolar trigone tumors.
本研究的目的是评估磁共振（MR）图像在确定磨牙后三角区肿瘤的T分期以及肿瘤与周围结构关系方面的诊断准确性。22例磨牙后三角区鳞状细胞癌患者接受了1.5T超导扫描仪的MR检查。在静脉注射0.2 mmol/kg钆喷酸葡胺（Gd-DTPA）后，采用自旋回波（SE）T1、T2加权序列以及短SE T1序列（TR 180 ms，TE 15 ms）进行检查。采用SE T1加权序列和梯度回波（GE）序列观察下颌骨。将结果与T分期（TNM分类）的病理数据以及周围结构的受累情况进行比较。22例患者中有19例呈正相关，准确率为86%。1例患者，MR将病变分类为T1期，但手术时发现由于下颌骨皮质浸润（浸润范围有限）为T4期。另1例患者，MR显示为T4期病变，因为下颌骨髓内存在低信号强度，注射Gd-DTPA后强化，但无皮质侵蚀，而病理数据显示为T2期病变（该信号强度是由炎症引起）。还有1例患者，MR将病变分类为T1期，但手术时证实为T2期病变。在评估周围结构的受累情况时，MR显示出较高的准确性、特异性和敏感性（> 90%）。观察到5例假阳性病例：2例是由于咬肌浸润，另外3例分别是由于肿瘤与周围结构紧密接触，导致翼内肌、下颌骨和扁桃体床浸润。仅观察到1例假阴性病例，表现为下颌骨髓浸润。在评估下颌骨髓低信号强度时，MR的准确率为87%，特异性为77%，敏感性为100%。1例患者发现沿下颌神经的神经周围扩散。总之，MR被证明在研究磨牙后三角区肿瘤的T分期以及检查周围结构关系方面具有高度准确性。
