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cystic-fibrosis-findings-on-chest-x-ray-and-lung-window-ct-scan

Cystic Fibrosis: Findings on Chest X-Ray and Lung Window CT Scan CFTR mutationàabnormal transmembrane Cl- transport in exocrine tissueà Author: Sean Kennedy Reviewers: Matthew Harding, Amogh Agrawal, Yan Yu, Ciara Hanly, Aman Wadhwani, Zesheng Ye (􏰃􏰄􏰁), Mark Montgomery* * MD at time of publication Collapsed alveoli appears white on x-ray Peribronchial Cuffing secretions become more viscous. (See relevant slide for CF pathogenesis.) As early as at birth, secretions collect in bronchial lumen, delaying mucociliary clearance Mucus plugs and obstructs bronchial lumen Air trapped distal to obstruction and cannot leave lungs Lung Hyperinflation Diaphragm domes below 10th posterior rib and 6th anterior rib on PA CXR Flattened hemidiaphragm, enlarged retrosternal space on lateral CXR With time, pulmonary capillaries gradually absorb gases in alveoli distal to obstruction àalveolar collapse (Atelectasis) Collapsed alveoli more solid and radiodense than airà↓X-ray penetration Adjacent structures may shift towards atelectasis on CXR In first few years of life, retained bronchial secretions serve as nidus for recurrent bacterial colonization and infection Late findings at 10- 30 years oldà secretion accumulation blocks inhaled air to affected lung segments àchronic hypoxia Inflammatory response (cytokines, nitric oxide and radical oxygen species) leads to bronchial and peribronchial destruction Hypoxia induces pulmonary capillary vasoconstriction Some airways are blocked more than others Leakage of fluid into bronchial walls & peri- bronchial regions. Inflammatory cytokines destroy elastic components of bronchi Accumulation of inflammatory exudate in bronchi Pulmonary artery hypertension à Blood backs up in pulmonary arteries Some segments of lung underventilated Fluid around bronchial walls is more radiodense than air à↓X-ray penetration àappears white Bronchiectasis: dilated, thickened, untapered bronchi on CXR/CT Fluid/mucus in bronchi is more radiodense than air, thus appearing white on imaging Edematous bronchi viewed end on are thickened and appear ring-like on CT/CXR Tramlines (AKA Tramtracking) Bronchus wider than corresponding blood vessel on CXR/CT Advanced bronchiectasis is saccular in appearance Mucus-filled bronchi form tubular opacities giving appearance of white fingers on CXR/CT Signet Ring Sign Bronchiectatic Cavities Mucoid Impaction (AKA Finger in glove sign) ↑ Blood dilates pulmonary arteries Blood backs up in right ventricle, dilating it Pulmonary arteries look wider on CXR. Main pulmonary artery >30 mm diameter on CT Right Ventricle Enlargement on CXR/CT Underventilated lung segments appear as lower intensity (darker) than normal ventilated segments which appear as normal intensity (brighter) Mosaic Changes on CT(non- contrast Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published June 13, 2013, updated Aug 18, 2021 on www.thecalgaryguide.com