ABSTRACT
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.
ABSTRACT
<p><b>OBJECTIVE</b>To assess the clinical diagnostic value of 18F-FDG imaging by coincidence circuit SPECT with low-dose CT in differential diagnosis of pulmonary lesions and mediastinal lymph node involvement, which can not be definitely diagnosed based on regular CT image in patients with non-small-cell lung cancer (NSCLC).</p><p><b>METHODS</b>By using GE-Millennium VG with Hawkeye, 18F-FDG imaging was carried out in 48 patients with suspected lung cancer. Clinical value of 18F-FDG imaging for diagnosing malignancy was evaluated through comparison with the final pathological results. Mediastinal lymph node involvement was also assessed through lesion-by-lesion comparison with pathologic results in 74 lymph node regions from 24 patients.</p><p><b>RESULTS</b>Final pathologic diagnoses of these patients were 36 malignancies consisting of 20 adenocarcinomas, 12 squamous cell carcinomas, 3 small cell carcinomas and I large cell carcinoma; 12 benign tumors including 6 pneumonias, 2 tuberculosis, 2 hamatomas, 1 cyst and 1 neurofibroma. Of 48 patients, uptake of 18F-FDG in the chest was found to be abnormal in 40. Correct diagnosis were made in 34 malignancies and 6 false positive lesions were excluded based on morphology and 18F-FDG uptake status of the lesion. There were 6 false positive and 2 false negative cases. Furthermore, extrathoracic metastases which were not showed on previous CT image in 4 patients including one in the adrenal gland and 3 in the bone were detected by 18F-FDG imaging. The sensitivity, specificity and accuracy of the 18F-FDG imaging for differentiating malignant tumor from benign was 94.4%, 50.0% and 83.3%, respectively. Squamous cell carcinoma was found to uptake more FDG than adenocarcinoma. For determination of mediastinal lymph node involvement, the sensitivity, specificity and accuracy of 18F-FDG imaging was 57.9% , 90.9% and 82.4%, respectively through lesion-by-lesion comparison; whereas, which was 61.5%, 81.8% and 70.8%, respectively, based on case-by-case comparison.</p><p><b>CONCLUSION</b>18F-FDG imaging by coincidence circuit SPECT with low-dose CT is quite helpful in differential diagnosis for patient with undetermined lesion on regular CT image, but it is limited for staging of lung cancer in the patients with non-small cell lung cancer.</p>