Value of ¹8F-FDG uptake on PET/CT and CEA level to predict epidermal growth factor receptor mutations in pulmonary adenocarcinoma.

PURPOSE: The identification of the mutation status of the epidermal growth factor receptor (EGFR) is important for the optimization of treatment in patients with pulmonary adenocarcinoma. The acquisition of adequate tissues for EGFR mutational analysis is sometimes not feasible, especially in advanced-stage patients. The aim of this study was to predict EGFR mutation status in patients with pulmonary adenocarcinoma based on (18)F-fluorodeoxyglucose (FDG) uptake and imaging features in positron emission tomography/computed tomography (PET/CT), as well as on the serum carcinoembryonic antigen (CEA) level. METHODS: We retrospectively reviewed 132 pulmonary adenocarcinoma patients who underwent EGFR mutation testing, pretreatment FDG PET/CT and serum CEA analysis. The associations between EGFR mutations and patient characteristics, maximal standard uptake value (SUVmax) of primary tumors, serum CEA level and CT imaging features were analyzed. Receiver-operating characteristic (ROC) curve analysis was performed to quantify the predictive value of these factors. RESULTS: EGFR mutations were identified in 69 patients (52.2 %). Patients with SUVmax ≥6 (p = 0.002) and CEA level ≥5 (p = 0.013) were more likely to have EGFR mutations. The CT characteristics of larger tumors (≥3 cm) (p = 0.023) and tumors with a nonspiculated margin (p = 0.026) were also associated with EGFR mutations. Multivariate analysis showed that higher SUVmax and CEA level, never smoking and a nonspiculated tumor margin were the most significant predictors of EGFR mutation. The combined use of these four criteria yielded a higher area under the ROC curve (0.82), suggesting a good discrimination. CONCLUSION: The combined evaluation of FDG uptake, CEA level, smoking status and tumor margins may be helpful in predicting EGFR mutation status in patients with pulmonary adenocarcinoma, especially when the tumor sample is inadequate for genetic analysis or genetic testing is not available. Further large-scale prospective studies are needed to validate these results.

Experience of low-dose aminophylline use to relieve minor adverse effects of dipyridamole in patients undergoing stress myocardial perfusion imaging.

BACKGROUND: Intravenous administration of aminophylline is widely adopted to reverse dipyridamole-related adverse effects (AEs) during stress myocardial perfusion imaging (MPI). The study aimed to investigate the efficacy of lower-dose aminophylline to relieve minor AEs. METHODS: 2,250 consecutive patients undergoing dipyridamole-stressed MPI were enrolled. Information concerning AE occurrence and dosages of aminophylline was collected to evaluate the efficacy of lower-dose aminophylline. A logistic regression was used to determine independent predictors of dipyridamole-related AE occurrence. RESULTS: No severe AE was noted. Overall mild AE incidence was 37.0% (833/2,250 patients). Initial low-dose (25 mg) aminophylline relieved symptoms in 98.8% of patients with mild AEs (823/833 patients). An extra 25 mg aminophylline sufficed to reverse all such AEs. Mean body mass index (BMI) differed significantly between patients with and without any AE [25.6 vs 25.1 (P = .009)]. There was no significant difference between two subgroups in mean age, male gender prevalence, body height and weight, dipyridamole dose/BMI, or prevalence of significant perfusion defect(s) on MPI. Multivariable logistic regression demonstrated BMI remained the independent predictor of dipyridamole-related AE occurrence (odds ratio 1.028, 95% confidence interval 1.007-1.049, P = .01). CONCLUSION: Low-dose (≦50 mg, and usually 25 mg) aminophylline seems sufficient to relieve mild dipyridamole-related AEs during stress MPI.

Imaging of metastatic pulmonary tumors following NIS gene transfer using single photon emission computed tomography.

The Na+/I- symporter (NIS) is a membrane glycoprotein that facilitates the uptake of iodine into thyroid follicular cells. Recently, we and others have demonstrated the feasibility of imaging subcutaneous xenografts expressing exogenous NIS, suggesting that NIS may serve as an imaging reporter gene to monitor vector delivery and therapeutic gene expression. In this study, we established NIS-expressing pulmonary tumors in nude mice to investigate the minimal tumor size required for in vivo detection of pulmonary tumors by single photon emission computed tomography (SPECT) with pinhole collimation. In order to define the anatomic location of NIS-expressing tumor nodules detectable by SPECT, we performed simultaneous, dual-isotope imaging. We injected 1 mCi 99mTc-MAA via tail vein to image pulmonary perfusion and injected 1 mCi Na125I intraperitoneally to image NIS-expressing tumors. Fused images showed that 99mTc-MAA perfusion defects correlated with NIS-mediated 125I uptake. Post-mortem analysis revealed that tumors 3 mm in diameter could be detected by SPECT with pinhole collimation. These studies demonstrate the feasibility of SPECT to detect pulmonary tumors expressing exogenous NIS in mice.

Conversion from FDG-negative to -positive during follow-up in a rare case of pulmonary lymphoepithelioma-like carcinoma.

A female patient aged 75 years presented with an incidental pulmonary nodule without FDG uptake when undergoing FDG PET/CT. Without obtaining histologic diagnosis, the follow-up FDG PET/CT 2 years later demonstrated intense FDG avidity within previously FDG-negative tumor. After surgery, the pathologic diagnosis is pulmonary lymphoepithelioma-like carcinoma (LELC). LELCs are unique because of histologic similarities with undifferentiated nasopharyngeal lymphoepithelioma and with a better prognosis as compared with other lung malignancies. However, the expression of FDG uptake in LELC has never been discussed. Herein, we describe a pulmonary LELC manifesting as a slowly growing tumor displaying conversion from FDG-negative to -positive avidity.

Tumoral calcinosis demonstrated on Tc-99m sestamibi scintigraphy.

A 61-year-old uremic male under hemodialysis underwent Tc-99m sestamibi scintigraphy due to suspicious secondary hyperparathyroidism. The images showed increased uptake in the right forearm, left shoulder, right knee and, to a lesser extent, in the left hip and the right thigh. Subsequent Tc-99m MDP bone scintigraphy and x-ray studies revealed intense extraosseous uptake and calcified masses in areas corresponding to those found in Tc-99m sestamibi scintigraphy, suggesting tumoral calcinoses. We demonstrate the rare case in which Tc-99m sestamibi was taken up by tumoral calcinoses.