Department of Oral and Maxillofacial Radiology, Field of Tumor Biology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 5-1, Shikata-cho, 2-Chome, Kita-ku, Okayama 700-8525, Japan.
Oral Oncol. 2011 Feb;47(2):147-52. doi: 10.1016/j.oraloncology.2010.11.009. Epub 2010 Dec 17.
Typical MR images of ameloblastomas on T2-weighted image (WI) or short inversion time inversion-recovery (STIR) show multiple bright high-signal-intensity loci on a high-signal-intensity background. Unilocular cystic-type ameloblastomas show homogeneously bright high signal intensity on T2WI or STIR as a water-like signal intensity. Therefore, it is difficult to distinguish unilocular cystic-type ameloblastoma from other cystic lesions such as keratocystic odontogenic tumors, radicular cysts (residual cysts) and dentigerous cysts only on the basis of MRI signal intensity. In the present study, we evaluated whether contrast-enhanced (CE)-T1WI and dynamic CE-MRI (DCE-MRI) could provide additional information for differential diagnosis in unilocular cystic-type ameloblastoma. Images from 12 cases of suspected unilocular cystic-type ameloblastoma were evaluated in the present study. Of them, 5 had areas suspected of indicating a solid component on T1WI and T2WI (or STIR). Ten had undergone additional CE-T1WI and DCE-MRI. On 5 of 10 cases of CE-T1WI, a tiny enhancement area was detected. On 6 of 10 DCE-images, a time-course enhanced area which was suspected to be a solid component was detected. CE-T1WI was helpful in the diagnosis of ameloblastoma because the tiny enhanced areas were taken to indicate possible solid components. Moreover, the rim-enhancement area on CE-T1WI could be divided into small regions of interest, and some of these showed slightly increased enhancement on DCE-MRI, which was taken to indicate a solid component and/or intramural nodule with focal invasion of ameloblastoma tissue. DCE-MRIs of the four remaining cases, which provided no clues to the diagnosis of ameloblastoma in the manner of the above descriptions, showed thicker rim enhancement than odontogenic cysts. Thus, CE-T1WI and DCE-MRI were helpful in the differential diagnosis of unilocular cystic-type ameloblastomas with homogeneously bright high signal intensity on T2WI or STIR.
在 T2 加权像（WI）或短反转时间反转恢复（STIR）上，典型的造釉细胞瘤的典型 MRI 图像显示在高信号强度背景上有多个明亮的高信号强度病灶。单囊型囊性造釉细胞瘤在 T2WI 或 STIR 上表现为均匀明亮的高信号强度，类似于水样信号强度。因此，仅基于 MRI 信号强度，很难将单囊型囊性造釉细胞瘤与其他囊性病变（如角化囊肿性牙源性肿瘤、根尖囊肿（残余囊肿）和含牙囊肿）区分开来。在本研究中，我们评估了对比增强（CE）-T1WI 和动态 CE-MRI（DCE-MRI）是否可以为单囊型囊性造釉细胞瘤的鉴别诊断提供额外信息。本研究评估了 12 例疑似单囊型囊性造釉细胞瘤的图像。其中，5 例在 T1WI 和 T2WI（或 STIR）上有疑似实性成分的区域。10 例行 CE-T1WI 和 DCE-MRI 检查。在 10 例 CE-T1WI 中有 5 例检测到微小增强区。在 10 例 DCE 图像中有 6 例检测到时间增强的疑似实性成分区域。CE-T1WI 有助于造釉细胞瘤的诊断，因为微小增强区域被认为是可能的实性成分。此外，CE-T1WI 上的边缘增强区域可以分为小的感兴趣区域，其中一些在 DCE-MRI 上显示出轻度增强，这被认为是实性成分和/或造釉细胞瘤组织的局灶性侵袭的腔内结节。其余 4 例的 DCE-MRI 未提供上述描述方式下诊断造釉细胞瘤的线索，其边缘增强较牙源性囊肿厚。因此，CE-T1WI 和 DCE-MRI 有助于对 T2WI 或 STIR 上呈均匀明亮高信号强度的单囊型囊性造釉细胞瘤进行鉴别诊断。
