The Frequency and the Degree of Fusion of the Lung on High-Resolution CT

PURPOSE: To evaluate the frequency and degree of fusion of the lung, as seen on high-resolution CT(HRCT). MATERIALS AND METHODS: In 210 patients high-resolution CT scans from the apex to the diaphragm were obtained at 1mm collimation and 7mm interval. We retrospectively analysed the frequency and degree of fusion of the lung bordering each interlobar fissure. Fusion of the lung was defined when fissure appeared without complete lobar separation. The degree of lung fusion was classified as mild (less than 1/3 of the fissure), moderate (greater than 1/3 and less than 2/3 of fissure), or severe (greater than 2/3 of the fissure). RESULT: In 90 of 210 patients, all fissures were identified. In 73 of these 90 (81.1%), lung fusion was noted, the most frequent site of this being between the right upper and right middle lobe (53.3%). The least frequent site was between the upper portion of the left upper and left lower lobe (32.2%). Am mild degree of fusion was most frequently found between the right middle and right lower lobe (83.9%), while a severe degree was most frequentl between the right middle and right upper lobe (50.0%), followed by the lingular division and the left lower lobe (41.9% ). CONCLUSION: HRCT can be used to were able to evaluate the frequency and degree of interlobar lung fusion.

Change of Pulmonary Arterial and Bronchial Diameter During Respiration: HRCT Findings

PURPOSE: To evaluate the changes and normal ranges of the artery-bronchus ratio (ABR) during respiration MATERIALS AND METHODS: We analyzed HRCT of 10 healthy adults. The HRCT findings of ten healthy adults were analysed. CT scanning was performed with 1 mm collimation at 3 mm intervals during full inspiration and full expiration, with a range during inspiration from 2 cm to 4 cm above the carina and from 4 cm above to 2 cm below the right hemidiaphragm. The range during expiration was from 1 cm to 3 cm above the carina and from 4 cm above to 2 cm below the right hemidiaphragm. ABiR (defined as the diameter of pulmonary artery divided by the inner diameter of the bronchus), ABoR (defined as the diameter of pulmonary artery divided by the outer diameter of the bronchus) and BLR (defined as the inner diameter of the bronchus divided by the outer diameter of the bronchus) were measured on the display console. RESULTS: The mean inner diameter of the bronchi was 2.04+/-0.73 mm during inspiration and 1.68+/-0.51 mm during expiration, while the mean diameter of the arteries was 3.95+/-1.03 mm during inspiration and 4.37+/-1.09 mm during expiration. The diameters of the bronchi were thus seen to increase during inspiration, and the diameters of the pulmonary arteries, to decrease. The mean thickness of the bronchial wall was 1.07+/-0.19 mm during inspiration and 1.06+/-0.24mm during expiration; thus, no change in thickness was seen during respiration (p<0.05). Mean ABiR was 2.01+/-0.60 (range 1.15-4.58) during inspiration and 2.59+/-0.74(range 1.16-4.9) during expiration, and in all cases the inner diameter of the bronchus was less than that of the accompanying pulmonary artery. Mean ABoR was 0.91+/-0.19 during inspiration and 1.09+/-0.22 during expiration. while for BLR, the corresponding fingures were 0.46+/-0.06, and 0.44+/-0.09. CONCLUSION: HRCT is a useful tool for evaluating changes in the pulmonary arteries and bronchi during respiration.

Can Anterior Junction Line be Used to Distinguish Right Middle from Right Upper Lobe on CT Scan?

PURPOSE: To evalvate the usefulness on a CT chest scan, of the anterior junction line as an anatomical landmark to distinguish the right middle and the right upper lobe MATERIALS AND METHODS: We found that the anterior junction line has a constant anatomical relationship with the right upper and middle lobe, and with this in mind, analysed connvcntional CT films of 86 patients with normal lung (group A) and 30 with architectural distortion (group B). On a series of slices, we compared the location of slice 1 with that of slice 2 (slice 1: the slice which includes the lowest portion of the anterior junction line, slice 2: the initial slice, in which the right middle lobe occupies the whole of the lung anterior to the right major fissure). RESULTS: In group A (n=86), the right upper lobe, as seen in the anteromedial zone of slice 1, was present in 83 cases (96.5%). The right upper lobe on slice 1 was absent in two cases (2.3%) in which a minor fissure was almost completely abent. In group B (n=30), the right upper lobe on slice 1 was absent in 19 cases (63.3%). CONCLUSION: We suggest that on a CT chest scan, the anterior junction line can be used as an anatomical landmark in the differentiation of the right middle from the right upper lobe, and as an indicator of the presence of architectural distortion.

Inspiratory and Expiratory Pulmonary CT: Change of Bronchial and Accompanying Pulmonary Arterial Diameter During Respiration in Healthy Adult Men

OBJECT: To evaluate changes in the diameter of bronchi and pulmonary arteries during respiration. MATERIALS AND METHODS: The ratio of the diameter of matched inner bronchi and accompanying pulmonary arteries was calculated from full inspiration and expiration HRCT of healthy men. RESULTS: In 106 pairs of matched bronchi and pulmonary arteries, the brohchial-arterial ratios were 0.61+/-0.18(upper lung), 0.72+/-0.21(lower lung), and0.65+/-0.20(total) at full inspiration and 0.51+/-0.32(upper lung), 0.52+/-0.15(lower lung), and 0.51+/-0.26(total) atfull expiration HRCT, denoting a statistically significant increase in bronchial diameter of the entire lung atfull inspiration. The inner diameter of the bronchus was larger than the diameter of the accompanying pulmonary artery by 0.1% at full expiration and 8.5% at full inspiration. CONCLUSION: The result of this study would be helpful in understanding the physiology of the lung during respiration.