核素骨显像在骶骨肿瘤术前诊断中的应用

目的 评价术前骨显像在骶骨肿瘤诊断中的临床价值。方法103例骶骨肿瘤患者术前进行了99Tcm-亚甲基二膦酸盐（MOP）全身骨显像，其中39例加做了局部断层显像。全身显像用于观察有无多骨病变及骶骨肿瘤对显像剂的摄取；断层显像用于进一步观察骶骨肿瘤的核素摄取特征。结果该组恶性肿瘤为65例，良性病变38例。骨显像在17．5％（18／103）的患者中检出了多发病灶，51．7％（12／21）的转移性骶骨瘤患者在骨显像上仅表现骶骨单发病变。骶骨肿瘤表现为放射性减低型者在平面显像中占46．6％（48／103），在断层显像中占84．6％（33／39）。放射性浓聚型或伴局部浓聚的放射性减低型骶骨肿瘤多为恶性病变；而单纯的放射性减低型骶骨肿瘤在无多骨病变发生的情况下多为良性病变；呈现“炸面圈”征的骶骨肿瘤则多为骨巨细胞瘤。结论骶骨肿瘤术前骨显像有助于全身多发病变的筛查，但对于单发的转移性肿瘤其诊断价值有限；观察肿瘤对显像剂的摄取特征，可为其鉴别诊断提供帮助。

Bone scintigraphy used in the preoperative diagnosis of sacral tumor

Objective To evaluate the clinical significance of bone scintigraphy in the preoperative diagnosis of sacral tumor. Methods Preoperative 99Tcm-methylene diphosphonate (MDP) whole body bone scintigraphy was performed in total of 103 patients with sacral tumor for whole body survey and radionuclide uptake in the sacral tumor. Of these 103 patients,39 had SPECT. According to the osteoblastic reaction in bone SPECT studies,patterns of tumor with a "hot" lesion was defined as type Ⅰ,a "cold" lesion accompanied with partial uptake was defined as type Ⅱ,a purely "cold" lesion was defined as type Ⅲ,and a "cold" lesion with marginal uptake which produced "doughnut sign" was defined as type Ⅳ. Imaging interpretation was correlated with the final pathologic diagnosis. Results Of the 103 patients,18 ( 17.5% ) had polyostotic involvement. About 46.6% (48/103 ) in planar and 84.6% ( 33/39 ) in SPECT showed decreased uptake at sacrum. Of the bone metastatic patients (n =21 ) ,12 (51.7%) had sole metastasis to sacrum. Tumor with type Ⅰ (6/6) or type Ⅱ (16/19) uptake was likely to be a malignancy,whereas type Ⅲ uptake tended to occur in the benign disease in those patients without polyostotic involvement( 5/7 ),and type Ⅳ was all appeared in giant cell tumors( n = 5 ). Conclusions Preoperative bone scintigraphy is useful in examination of polyostotic involvement for the patients with sacral tumor,but it is limited for diagnosing isolated sacral metastatic disease. Tumor uptake on bone scintigraphy can be helpful in differential diagnosis of sacral tumor.