鼻窦和颞骨成骨细胞瘤CT和MRI诊断

CT and MRI diagnosis of osteoblastoma in paranasal sinus and temporal bone

目的探讨鼻窦和颞骨成骨细胞瘤CT和MR I表现,提高其诊断准确性。方法回顾性分析8例经病理证实的鼻窦和颞骨成骨细胞瘤的影像学资料,分析其CT和MR I表现。结果6例为良性成骨细胞瘤,2例为侵袭性成骨细胞瘤;发生于鼻窦者6例,颞骨者2例。CT表现:良性成骨细胞瘤边界清楚,圆形2例、椭圆形4例,周边伴有完整的骨壳,病灶内见点状、结节状、条状钙化或骨化,压迫邻近的结构;侵袭性成骨细胞瘤部分边界模糊,形态不规整,骨壳不完整,外周可见软组织肿块,内伴有不规则形的钙化或骨化,侵犯邻近结构。MR I表现:与脑实质比较,T1W I为等信号者4例,低信号者2例,T2W I信号不均匀,但病灶内部均见数量不一的极低信号影,对应CT上钙化或骨化区;4例骨壳在T1W I和T2W I均表现为低信号环,1例骨壳仅在T2W I显示低信号,1例骨壳在T1W I和T2W I均难以显示;增强后扫描呈中至显著强化,良性为较均匀强化,而侵袭性为不均匀强化;邻近脑膜可见不同程度强化,良性较均匀,侵袭性不规则且范围更大。结论CT是该病诊断和鉴别诊断的主要影像检查方法,MR I可更清楚、准确显示病变侵犯的范围,为治疗提供可靠依据,可作为1种补充的影像检查方法。

Objective To investigate the CT and MRI findings of osteoblastoma in paranasal sinus and temporal bone so as to promote the diagnostic accuracy. Methods All 8 patients with osteoblastoma were verified by pathology. CT and MRI findings were analyzed retrospectively. Results Six cases were benign and 2 invasive. In 6 cases the lesion occurred in paranasal sinus and 2 in temporal bone. On CT scans, benign osteoblastoma revealed well-defined margin, round-shapa showing in 2 cases and oval-shapa in 4 cases with compression of the adjacent structure. The lesion showed stippled, nodular or linear calcification or ossification with intact bony shell in the periphery. Aggressive osteoblastoma demonstrated partial hazy margin and irregular shape with invasion of the adjacent structure. The lesion had incomplete bony shell with soft tissue element in the periphery. More irregular shapes of calcification or ossification may be found within the focus in aggressive osteoblastoma. On MR T1 WI, the lesions showed isointense signal compared to brain in 4 cases and hypointeuse signal in 2 cases. On T2WI, the lesions showed heterogeneous signal with marked hypointense foci of calcification or ossification which were showed more clearly on CT. Postcontrast MR imaging scans demonstrated moderate to marked enhancement in these cases. Enhancement in benign lesions were relatively homogeneous and inhomogeneous in aggressive lesions. Bony shell showed hypointeuse signal on both T1 WI and T2 WI in 4 cases, thin hypointense signal rim only on T2 WI in 1 case and no signal on T1WI and T2WI in 1 case. Adjacent meninges showed uniform thickening and enhancement in benign osteoblastoma, more irregular and extensive in aggressive lesions. Conclusion CT is the modality of first choice in diagnosis of osteoblastoma. MRI can demonstrate optimally the invading extent and provide more accurate information for therapy as a complemental imaging method.