Radiology, Vol 178, 163-168, Copyright © 1991 by Radiological Society of North America
Inferior hilar window
CK Park, WR Webb and JS Klein
Department of Radiology, University of California Medical Center, San Francisco 94143-0628.
The authors undertook a study to determine the ability to detect mass or
adenopathy in the "inferior hilar window," a normally avascular region
inferior to the shadow of the right pulmonary artery and vein and anterior
to the descending left pulmonary artery on lateral chest radiographs. Fifty
patients with normal results of thoracic computed tomography (CT) and 25
with unilateral or bilateral hilar masses or adenopathy (defined as opacity
greater than 10 mm in diameter) were selected retrospectively. Patients
with concomitant pulmonary masses or consolidation at CT that might be
confused with or obscure an inferior hilar mass or adenopathy were excluded
from study. The 75 corresponding lateral chest radiographs were then
evaluated blindly. Forty-seven of the 50 normal cases were correctly
interpreted (specificity = 94%). The anterior walls of the right and left
lower lobe bronchi were seen in 36% and 84% of normal cases, respectively;
the average thickness was 2 mm. Of the 25 patients with inferior hilar
masses, 22 were recognized as having abnormalities (sensitivity = 88%); two
of the three patients with false-negative results had right hilar masses.
Overall accuracy was 92%. For only eight (32%) of the 25 patients was the
laterality of abnormality correctly diagnosed. Evaluation of the inferior
hilar window on lateral chest radiographs is accurate in assessing the
presence or absence of inferior hilar mass or adenopathy.
