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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
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The earliest chest X-ray change in cystic fibrosis is:
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The correct answer is  The earliest chest x-ray finding in CF lungs is hyperinflation, reflecting small-airways obstruction. Later, signs of luminal mucus impaction, bronchial cuffing, and finally bronchiectasis, e.g., ring shadows, are noticed. Ref: Harrisons Principles of Internal Medicine, 18th Edition, Page 2149.