JUXTAPHRENIC PEAK IN UPPER AND MIDDLE LOBE VOLUME LOSS - ASSESSMENT WITH CT

PURPOSE: To investigate the anatomic basis for the juxtaphrenic peak ( JP) in upper and/or middle lobe volume loss through radiographic and c omputed tomographic (CT) correlation. MATERIALS AND METHODS: Chest rad iographs and CT scans were reviewed in 32 patients with upper or middl e lobe volume loss. The study included 33 cases of volume loss: 12 aff ected the left upper lobe; 12, the right upper lobe; five, the right u pper and middle lobes; and four, the middle lobe. JPs and linear opaci ties identified on chest radiographs were correlated with juxtadiaphra gmatic structures on CT scans. RESULTS: A JP was identified in 22 of 3 3 (67%) cases, including nine of 12 (75%) with left upper lobe volume loss and eight of 12 (67%) with right upper lobe, four of five (80%) w ith combined upper and middle lobe, and one of four (25%) with middle lobe volume loss. The JP was due to an inferior accessory fissure in 1 4 of 22 (64%) cases. Other causes included a medial septum and an acce ssory fissure other than the inferior accessory fissure. CONCLUSION: T he JP sign is seen in the majority of cases with upper lobe or combine d upper and middle lobe volume loss. The sign is most commonly related to an inferior accessary fissure.