Pulmonary sclerosing pneumocytoma images under MSCT and 18F-FDG PET/CT and its misdiagnosis

Objective:To investigate the manifestations of pulmonary sclerosing pneumocytoma by multi-slice spiral CT (MSCT) and ^18F-FDG PET/CT in order to improve the accuracy of preoperative diagnosis. Methods:42 cases of PSP confirmed by pathology after operation were retrospectively analyzed. The distribution, size, shape, special signs and metabolic characteristics of lesions were observed. The relationship between the maximum diameter of lesions and clinical symptoms and the correlation between the maximum diameter of lesions and the maximum standardized uptake value (SUVmax) were analyzed. Results:MSCT plain scan was performed in 36 cases, enhanced in 29 cases, MSCT observed vessel marginal sign in 21 cases, air crescent sign in 9 cases, halo sign in 7 cases, calcification in 20 cases, transfissure sign in 6 cases, pleural plain scan in 23 cases;mean value of CT plain scan (36.50±21.65) HU, mean arterial phase of enhanced CT (73.13±37.22) HU, venous phase (74.78±18.36) HU;There was no significant difference in the maximum diameter of lesions between the symptomatic group and the asymptomatic group (P=0.283);^18F-FDG PET/CT in 16 cases, showed 1 case of low uptake (6.25%), 6 cases of moderate uptake (37.50%), 9 cases of high uptake (56.25%) and 3 cases of hilar and mediastinal lymph node hypermetabolism. There was no significant difference between the size of typical lesions and SUVmax(P=0.212);There was no significant correlation between the size of atypical lesions and SUVmax (P=0.253), and between the size of typical and atypical lesions and SUVmax (P=0.066). There were 8 cases of PSP diagnosed correctly before operation, with an accuracy of 19.05%, 2 cases of hamartoma, 3 cases of inflammatory pseudotumors, 3 cases of tuberculoma, 3 cases of metastasis and 10 cases of malignant tumors. Conclusion:The metabolic characteristics of PSP lesions in MSCT such as "blood vessel marginal sign", "air crescent sign", "halo sign", "transfissure sign", "calcification", "pleura sticking" and 18F-FDG PET/CT can show malignant tumors, which provide important basis for the diagnosis of PSP.

Optical sampling system using periodically-poled lithium niobate waveguide and nonlinear polarization rotation mode-locked fiber laser

A novel design of optical sampling system has been developed by using sum-frequency generation （SFG） in a periodically-poled lithium niobate （PPLN） waveguide and using passive mode-locked fiber laser pulses as optical sampling pulses. The system achieved high temporal resolution and high sensitivity using a 30 mm length PPLN with quasi phase match period of 19.3 μm and 151 fs sampling pulses which were generated by passive modelock fiber laser based on nonlinear polarization rotation （NPR）. Clear eye-diagram of 10 Gbit/s non-return-to-zeros （NRZ） pseudorandom binary sequence （PRBS） optical signal were successfully reconstructed by this system.