HRCT STUDIES OF LUNG ANATOMY

accurate definition of lung anatomy is the first, necessary step to ob tain an accurate and early diagnosis of diffuse and focal lung disease with HRCT. Secondary lobules are visible with conventional CT and HRC T as polygonal portions of lung parenchyma, surrounded by thin and inc omplete septa and centred by a dense dot; acini are sometimes visible as rounded structures with a central dot. Morphological definition of these structures in normal subjects will greatly help in characterizin g early signs of parenchymal disease.