Table 1.

Radiographic characteristics used in differentiating pulmonary nodules.

Characteristics	Modalities	Conclusion	Reference
Size Growth Rate	CT CT	Nodule size larger than 2 cm in diameter having a higher rate of malignancy than smaller nodules Pulmonary nodules with high growth rate were proved to be malignant	MacMahon et al. [42] Ko et al. [43]
Morphology Margin Shape Calcification	CT CT	A nodule with an irregular or speculate margin with distortion of adjacent vessels is likely to be malignant, while one with smooth and well defined is usually benign Calcification is recognized as benign pattern of pulmonary nodules Higher prevalence of malignancy among nonsolid and part-solid nodules than among solid nodules	Erasmus et al. [44]
Attenuation Solid Non-solid Part-solid SUVmax DWI*	CT FDG-ET* MRI	Higher SUVmax* indicates more probability of being malignant ADC* value of benign lesions was statistically higher than that of malignant tumours LSR* evaluation was useful and practical	Ohno et al. [25] Liu et al. [45] Koyama et al. [46]

^*DWI: Diffusion Weighted Imaging; FDG-PET: Fluorodeoxyglucose-Position Emission Tomography; ADC: Apparent Diffusion Coefficient; SUV: Standardized Uptake Value; LSR: signal–intensity ratios between lesion and spinal cord.