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What is HRCT is investigation of choice for? and explain in detail?
Ans. D. Interstitial lung disease.HRCT Lungs:# BASIC PRINCIPLE- Bone algorithm (Basic Principle)6- 1 mm sections 6- Narrow beam collumation 6- Small field of view6- Large matrix size# INDICATIONS (Investigation of choice for)- LUNGS:* Interstitial Lung Disease (ILD)6* Bronchiectasis ("Signet-ring" sign) 6* EmphysemaILD: Radiologic patterns of INTERSTITIAL LUNG DISEASES (ILD) | |||||Reticular patternNodular patternReticulonodularSeptal "Groundglass"pat"Tree-in-bud"|||||# Fibrosing alveolitis# Asbestosis# Sarcoidosis# Chro allergic alveolitis# LCH# LAM# Silicosis# CWP# Sarcoidosis# TB# Subacute EAA# LCH# Sarcoidosis# Lymphangitis Ca# Interst pulm edema# Lymphangitic Ca# P. jerovecii Atyp TB# NSIP# Pulm h'ge# Alveolar proteiniosis# Eosinophilic pneumoEndo TB# Collagen vas ds# Ex. Allergic alveolitis HRCTDisease1. Reticular pattern# Many ILDs2. Multiple cysts# Lymphangioleomyomatosis (LAM)# Pulmonary Histiocytosis3. Lepidote growth# Bronchoalveolar cancer4. Crazy paving# Alveolar proteinosis > silocosis5. "Tree-in-bud" appearance# Endobronchial TB and# Atypical mycobacterial TB6. 'Ground glass' hazzinessEarliest radiological finding of any ILD7. Bilateral perihitar ground glass haziness, especially in a immunocompromised individualPCP | | |ILDs primarily affecting UZs ILDs primarily affecting LZs# Extrensic ellergic alveolitis# Coal workers pneumoconiosis# Langerhan's disease# Ankylosing spondylitis# Sarcoidosis# Silicosis (Mnemonic: E-CLASS) # Fibrosing alveolitis# Asbestosis (bilat basal affection)# Interstitial pulmonary edema# Lymphangitis carcinomatosa (Mnemonic: FAIL)Additional Educational points:Role of CT, PET scan, Bronchoscopy and Image guided biopsy in Pulmonary Nodule evaluation: Investigation for SPNSensitivitySpecificityAccuracyComment1.Transthoracic FNAB95-100%91%--# Gives tissue diagnosis;# Best for evaluating SPN.2.PET (FDG) scan92-100%52-100%94%# Best non-invasive tool for evaluating SPN.3.CECT98%73%85%# If a chest x-ray shows a lung nodule, usually CECT is best to roughly know whether it is infective/congenital/ neoplasm. And main advantage of CT is it maps the lesion, apart from characterizing the lesion.# Further CT is best to guide lung & mediastinal biopsies.4.HRCT---# Not primarily useful for solitary lung nodule evaluation.# It is for diffuse or interstitial lung diseases.5.MRI---# Not much preferred for chest imaging except for pathologies like Pancoast tumor; Vascular lesions, Neurogenic tumors, etc.6.Bronchoscopy---# Should be used for central lesions (if at all) and endobronchial lesions.# Can be used if CT chest is normal.SPN=Solitary Pulmonary Nodule.