The differential diagnostic value of 99Tcm-MIBI SPECT combined with localizable CT imaging in oxygen intervention for lung lesions

Objective: To investigate the differential diagnostic value of 99Tcm-methoxyisobutylisonitrile (MIBI) SPECT combined with localizable CT in the evaluation of oxygen intervention for suspicious lung lesions, and to establish a cost-effective imaging modality in the detection of malignant lung lesions. Methods: From September 2008 to March 2009, 47 consecutive patients with suspicious malignant lung lesions underwent 99Tcm-MIBI SPECT/CT prospectively. Patients with suspicious pneumonia were treated with antibiotics for about 4 d before imaging. All patients were canalized with a nostril tube for oxygen inhalation before 99Tcm-MIBI injection. SPECT combined with localizable CT of the chest was performed at 10 min and 2 h after 99Tcm-MIBI injection. The uptake ratios of lesion to contralateral normal lung parenchyma(early uptake ratio: EUR and delayed uptake ratio: DUR) were compared using independent-samples t-test. In addition,the diagnostic efficiency of uptake ratios of lung lesions was analyzed with receiver operating characteristic (ROC) curve. Results: Forty-seven patients (primary lung cancers: 32, metastatic tumors of the lung: 4, benign lung diseases: 11) had 51 lung lesions, including 39 malignant and 12 benign lung lesions. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were 94.9% (37/39), 83.3% (10/12), 92.2% (47/51), 94.9% (37/39) and 83.3% (10/12), respectively. The EUR of malignant lesions was 2.95 ± 1.16, whereas of benign lesions was 1.43 ±0.33. The DUR of the malignant lesions was 3.19 ± 1.74, whereas of benign lesions was 1.60 ± 0.32. Both EUR and DUR were significantly different between malignant and benign lung lesions,respectively (t= -4.44,-3.12, respectively, both P<0.01). The ROC curve showed that EUR value ≥1.625 provided the sensitivity of 97.4% (38/39) and specificity of 83.3% (10/12); DUR value ≥ 1.75 provided the sensitivity of 94.9% (37/39) and specificity of 83.3% (10/12). Conclusion: 99Tcm-MIBI SPECT combined with localizable CT imaging in oxygen intervention has a potential value in differentiating malignant from benign lung lesions. (authors)