miliary tb ct finding

Nodule size and number: Numerous micronodules usually 1–3 mm (sometimes up to ~4–5 mm) and often too many to count. 

Distribution: Random (hematogenous) distribution with no centrilobular clustering or polygonal secondary-lobule pattern; nodules are bilateral and diffuse across all lung zones (may show mild basilar predominance acutely and mild upper-zone predominance chronically). 

Margins and background: Nodules often sharply marginated but can be ill-defined; ground-glass attenuation or interlobular septal thickening/reticular change may be present superimposed on the nodules.