Basics of CT chest including different views and how to read a chest ct
- 1. BASICS OF CT CHEST MODERATOR- DR VAIBHAV BHARGAVA DR KISHORE MANGAL PRESENTER-DR MANISH K.SAINI
- 2. THE BASICS 1. The different options for CT imaging of the lung 2. An approach to looking at chest CT’s 3. A few disease patterns that will help you impress
- 3. CT TYPES 1. Standard 2. High Resolution 3. Low Dose 4. CT Angio
- 4. 1. STANDARD CT Slice thickness: 3-10 mm scans a large volume, very quickly Covers the full lung +/- contrast Indications CXR abnormality Pleural and mediastinal abnormalities Lung cancer staging F/U metastases Empyema vs abscess
- 5. narrow x-ray beam collimation: 1-1.3mm vs. conventional 3-10mm cross sections are further apart: 10 mm high definition images of lung parenchyma: vessels, airspaces, airway and interstitium No contrast 2. HIGH RESOLUTION (HRCT) STANDARD CT HRCT
- 6. 2. HIGH RESOLUTION (HRCT) Indications Hemoptysis Diffusely abnormal CXR Normal CXR with abnormal PFT’s Baseline for pts with diffuse lung disease Solitary pulmonary nodules Reversible (active) vs. non-reversible (fibrotic) lung disease Lung biopsy guide F/U known lung disease Assess Rx response
- 7. Premise: lower dose radiation will not reduce the diagnostic functionality of the scan (eg. 250 mAs 50 mAs) Detail is decreased Uses Screening ongoing trials F/U infections post lung transplant metastases 3. LOW DOSE
- 8. contrast injected into peripheral vein injection timing/rate controlled automatically dye is where you want it during scan replaced conventional catheter angiogram Indications Pulmonary embolism Aortic aneurysms Aortic dissection Risks Iodinated contrast: Allergic/ nephrotoxic 4. ANGIOGRAPHY (CTA)
- 9. Three Windows 1. Soft Tissue APPROACHING THE ANATOMY 2. Bone 3. Lung
- 10. Look at these structures Thyroid Chest wall Pleura Heart Chambers CA calcifications Pericardium Vessels Aorta PA Smaller vasculature Nodes mediastinal axillary 1. SOFT TISSUE WINDOW
- 11. Ascending aorta Descending aorta Main pulmonary artery L pulmonary artery R pulmonary artery SVC Azygous vein Esophagus
- 12. Manubrium/ Sternum Vertebrae R Ribs L Ribs 2. BONE WINDOW
- 13. 3. LUNG WINDOW AIRWAYS Bronchial Tree Central LLL LUL Fissure RUL RLL PARENCHYMA Fissure
- 14. 1. Air Bronchograms 2. Bronchiectasis 3. Septal Thickening 4. Ground Glass Opacity 5. Emphysema 6. Nodules 7. Filling Defect COMMON PATHOLOGIC FEATURES
- 15. Description • Bronchi become visible due to increased attenuation of surrounding lung • Implies proximal bronchi patency • Excludes pleural or mediastinal lesion DDx • Non-obstructive atelectasis • Pneumonia • Pulmonary edema • Hemorrhage • Bronchioloalveolar carcinoma • Lymphoma 1. AIR BRONCHOGRAMS
- 16. Dilatation of medium-sized bronchi (>2 mm) impaired clearance recurrent infection bronchial damage Types 1. Cylindrical 2. Cystic 3. Varicose HRCT is diagnostic tool of choice DDx • Infection • Bronchial obstruction • Cystic fibrosis • Primary ciliary dyskinesia 2. BRONCHIECTASIS • Immunodeficiency states • alpha 1-Antitrypsin deficiency • RA and Sjögren • Pulmonary fibrosis
- 17. • abnormalities of interlobular septa or peripheral alveoli • thickening and outlining of the secondary pulmonary lobules is best seen on HRCT • often well depicted in the apices Most Common Causes • pulmonary edema • pulmonary hemorrhage • lymphangitic cancer spread 3. SPETAL THICKENING
- 18. • common nonspecific finding • decreased air content without totally obliterating the alveoli • increased lung opacity not sufficient to obscure pulmonary vessels 4. GROUND GLASS OPACITIES DDx • Alveolitis or interstitial pneumonitis – Hypersensitivity pneumonitis – IPF – Sarcoidosis • Pulmonary edema • Resolving pneumonia/ hemorrhage Early Dense
- 19. • permanent enlargement of air spaces distal to the terminal bronchioles • destruction of the walls without obvious fibrosis Young pt with bullous emphysema at the lung bases. What’s the diagnosis? DDx • smoking • alpha 1-Antitrypsin deficiency • IV drugs • Immundeficiency • Vasculitis • Connective tissue disorders 5. EMPHYSEMA
- 20. 3 Types 1. Centriacinar/lobular respiratory bronchioles periphery upper half of lungs smoking 2.Panacinar destroys entire alveolus uniformly lower half of lungs homozygous alpha1-antitrypsin deficiency 3.Distal acinar/paraseptal distal airway, alveolar ducts, and alveolar sacs around the lung septae or pleura apical bullae may spontaneously pneumothorax 5. EMPHYSEMA What 2 types are found here?
- 21. CT can detect nodules 3-4 mm Benign • Small, unchanged over 2 years • Less than 15-20 HU • fat within (hamartoma) • halo sign: ground-glass surrounding nodule indicates infection Malignant • Enhancement of greater than 20 HU • Caution: active granulomas/ infectious lesions • Spiculated • Multiple 6. NODULES Can you spot the nodule?
- 22. Circumscribed nodules suspect metastatic disease Septated nodules, suspect primary lung malignancy Neoplastic Infectious Inflammatory Benign (hamartoma) Bronchogenic Ca Mets Lymphoma Granuloma Abscess Rheumatoid arthritis Wegener’s Sarcoidosis 6. NODULES
- 23. Pulmonary Embolism is a well defined hypodensity in the pulmonary artery CTA sensitive for PE (90%) can’t evaluate arteries below 4th segmental level DDx: Anatomical landmarks and variants eg intersegmental nodes Vascular tumor invasion Technical psuedo filling defects (eg flow artifact) 7. FILLING DEFECTS