Visibility and variability of pleural fissures on normal digital chest radiographs of 1,000 healthy adults.

Abstract

To investigate the visibility and variability of pleural fissures on digital chest radiographs. Posteroanterior digital chest radiographs of 566 males and 434 females were retrospectively reviewed for the frequencies and/or appearances of various pleural fissures. The right only, left only and bilateral minor fissures were visible in 722 (72.2 %), 1 (0.1 %) and 7 (0.7 %) subjects, respectively. The right minor fissures were visible as more than one line in 219 (30.0 %) subjects, i.e., 2, 3 and 4 lines in 214 (29.3 %), 4 (0.5 %) and 1 (0.1 %), respectively. The 955 visible right minor fissures exhibited variable length (<1/3 of right hemithorax, 17.8 %; 1/3-2/3, 60.1 %; >2/3, 22.1 %), alignment (medial higher 40.9 %; lateral higher 54.2 %; horizontal 4.8 %) and contour (convex upward 68.6 %; convex downward 2.7 %; flat 24.9 %; sigmoid 3.8 %). Superolateral major fissures were visualized in 14.8 % (right only 3.0 %; left only 9.0 %; bilateral 2.8 %), superomedial major fissures in 0.3 % (right 0.1 %; left 0.2 %), vertical fissures in 0.5 % (right 0.2 %; left 0.3 %), inferior accessory fissures in 5.4 % (right 4.8 %; left 0.6 %), right superior accessory fissures in 1.2 % and azygos fissures in 0.2 %. The right minor fissure was most frequently visible and exhibited variable appearances. Other pleural fissures were occasionally seen.