Radiology of the Respiratory System PDF - 2nd April 2024

Lecture title: Radiology of the Respiratory System 2nd April 2024 Dr Khalid Bashir FRCEM FRCS Department Head of Clinical Academic Education Learning objectives Analyze and compare the different imaging modalities for the respiratory system Develop a diagnostic imaging pathway for investigating comm...

Lecture title: Radiology of the Respiratory System 2nd April 2024 Dr Khalid Bashir FRCEM FRCS Department Head of Clinical Academic Education Learning objectives Analyze and compare the different imaging modalities for the respiratory system Develop a diagnostic imaging pathway for investigating common respiratory symptoms Evaluate the effectiveness of various diagnostic imaging pathways for investigating common respiratory symptoms Apply a systematic approach to analyze chest X-rays Recognize the radiological appearances of common respiratory pathologies Different imaging modalities for the respiratory system Chest X-ray (CXR): A common imaging test that uses a small amount of radiation to produce images of the chest, including the lungs and heart. Computed Tomography (CT): A more detailed imaging test that uses X-rays and computer technology to produce crosssectional images of the chest. Magnetic Resonance Imaging (MRI): A non-invasive imaging test that uses a powerful magnetic field and radio waves to produce detailed images of the chest. Ultrasound: A non-invasive imaging test that uses high-frequency sound waves to produce images of the chest. Positron Emission Tomography (PET): A nuclear medicine imaging technique that uses radioactive substances to produce threedimensional images of the chest. Single-Photon Emission Computed Tomography (SPECT): Another nuclear medicine imaging technique that produces threedimensional images of the chest using radioactive tracers. Each modality has its own advantages and disadvantages, as well as considerations for patient safety, cost, and availability. Chest X-ray (CXR) for respiratory diseases Uses: Diagnosing, tracking lung conditions like pneumonia, TB, COPD, cancer. Spotting chest issues: tumors, heart size, lung fluid, collapses. Checking device placements: tubes, catheters, airway aids. Respiratory disease screens for at-risk groups, e.g., TB in medics. Limitations: CXR might need more tests for accurate diagnosis. Small cancers, embolisms may go undetected. Some conditions, like asthma or bronchitis, are not clearly shown. Repeated X-rays increase cancer risk due to radiation exposure. May not be suitable for everyone, like pregnant patients or kids CT scan for respiratory diseases Uses:  CT is useful for detecting small lung nodules, pulmonary embolisms, and lung cancers that may not be visible on chest xrays.  It can help identify the extent and severity of respiratory diseases such as pneumonia, bronchiectasis, and interstitial lung disease.  CT can provide detailed information about the structures of the chest and lungs  CT can help guide needle biopsies or other procedures to obtain samples of lung tissue for diagnosis. Limitations:  CT exposes the patient to higher levels of radiation compared to chest x-rays, which may increase the risk of cancer.  CT scans are more expensive and time-consuming than chest x-rays  Some patients may experience claustrophobia during the scan Magnetic Resonance Imaging (MRI) for respiratory diseases Uses(MRI is not a routine imaging modality for pulmonary diseases, as it is generally less sensitive than computed tomography (CT) and has limited ability to evaluate lung parenchyma) Identification and evaluation of pulmonary nodules and masses Evaluation of mediastinal and hilar lymphadenopathy Diagnosis and monitoring of interstitial lung diseases Assessment of pulmonary fibrosis Evaluation of pulmonary hypertension and congenital heart diseases Limitations MRI is more expensive than other imaging modalities such as CXR and CT. MRI can be time-consuming, especially for patients with respiratory distress who may not be able to hold their breath for the necessary period. MRI may not be able to differentiate between certain types of tissues or pathologies, such as calcification and fibrosis. Ultrasound for respiratory diseases Uses  Identification and characterization of pleural effusion and pneumothorax  Evaluation of lung parenchyma for pneumonia and lung masses  Assessment of diaphragmatic function  Guidance for needle biopsy and drainage procedures Limitations  Limited penetration through air-filled structures  Operator-dependent technique with a learning curve  Limited ability to visualize deep lung parenchyma  Difficulty in distinguishing between different types of pleural effusions Positron Emission Tomography (PET) for respiratory diseases Uses:  PET is used to detect lung cancer and metastases in patients with suspected or confirmed lung cancer.  PET can be used to assess the effectiveness of cancer treatments, such as chemotherapy and radiation therapy.  PET can be used to differentiate between benign and malignant pulmonary nodules. Limitations:  PET has limited spatial resolution and cannot detect small lesions or small areas of inflammation.  PET has a relatively high cost compared to other imaging modalities.  PET requires the use of radioactive tracers, which may pose some risk to patients, particularly those with kidney disease or pregnant women Single-Photon Emission Computed Tomography (SPECT) in respiratory diseases: Uses  Provides detailed information about the function of specific organs in the respiratory system  Can detect subtle changes in blood flow, oxygen consumption, and other physiological processes in the lungs  Can be used to identify the location and extent of lung tumors or infections Limitations  Has lower spatial resolution than other imaging modalities, such as CT or MRI  May require the injection of a radioactive tracer, which carries a small risk of side effects or allergic reactions  Cannot be used in patients with pacemakers or other implanted medical devices that may be affected by the electromagnetic fields used in the imaging process Basics Right patient? Right radiograph date? Right viewing conditions? All images? Why are we doing this? Did you look at old ones? Posterior-Anterior and Lateral View: Posterior-Anterior (PA) View: The X-ray machine is positioned behind the patient and the X-ray beam passes through the body from back to front, towards the film plate positioned in front of the chest. This view is used to evaluate the overall condition of the lungs and heart, as well as the chest wall, diaphragm, and mediastinum. The heart appears larger and closer to the chest wall in this view. The PA view is the standard view used for chest X-rays. Lateral View: The X-ray machine is positioned to the side of the patient and the X-ray beam passes through the body from side to side, towards the film plate positioned behind the chest. This view is used to evaluate the condition of the lungs and heart from a different perspective, allowing for the detection of abnormalities that may not be visible on the PA view. The lateral view shows the heart and lungs from a different angle, making it easier to assess the size and location of any abnormalities, such as fluid or air in the chest. The lateral view is usually done in combination with the PA view for a complete evaluation of the chest. Recommended steps for reading x-ray chest 1. Projection: Confirm if the X-ray is AP or PA. For example, in a PA view, the scapulae should be outside the lung fields. 2. Technical Adequacy: Assess the quality of the X-ray. For example, a good-quality X-ray will show 5 to 7 anterior ribs above the diaphragm at the mid-clavicular line. 3. Tubes and Lines: Look for medical devices. For instance, an endotracheal tube should be 5 cm above the carina. 4. Cardiomediastinal Contour: Examine the heart and mediastinum. For example, the cardiac silhouette should not exceed 50% of the thoracic width on a PA film. 5. Hila: Evaluate the hila for abnormalities. Typically, the right hilum is higher than the left. 6. Airways, Lungs, and Pleura: Check these areas carefully. For instance, look for patchy areas that may indicate pneumonia. 7. Bones and Soft Tissue: Inspect the bones for fractures. For example, check the clavicles and ribs for any breaks. 8. Review Areas: Look at commonly missed spots. Such as the apices for signs of tuberculosis or the costophrenic angles for effusions ABCDE approach The ABCDE approach is a systematic method for analyzing chest X-rays and ensures that key aspects of the image are not missed. Each letter stands for a specific component to check: A - Airway: Check the trachea and main bronchi for any signs of displacement, obstruction, or narrowing. B - Breathing: Assess the lung fields for signs of consolidation, collapse, pulmonary edema, pneumothorax, and masses. Also, check for lung hyperinflation. C - Circulation: Examine the heart size and shape to identify cardiomegaly or abnormal cardiac contours. Look at the aortic knob and the pulmonary vasculature for any abnormalities. D - Diaphragm: Evaluate the diaphragms for elevation, free air under the diaphragm (which can indicate a perforated viscus), and pleural effusions. E - Extras: Look at bones for fractures, soft tissues for swelling or subcutaneous emphysema, and check for any medical devices (e.g., pacemakers, central lines, endotracheal tubes) to confirm correct placement and identify any potential complications. Clinical Scenario A 60-year-old male presents to the emergency department with shortness of breath and chest pain. On examination, there is reduced breath sounds and dullness to percussion on the right side. A chest X-ray shown below, what are the findings and which of the following is the most common cause? A. Pneumonia B. Pulmonary embolism C. Congestive heart failure D. Lung cancer E. Tuberculosis X-chest findings Blunting of the costophrenic angle due to the presence of fluid. Increased opacity in the hemithorax where the effusion is present. A possible shift of the mediastinum and trachea away from the side with more fluid, indicating a large volume of effusion or tension effusion. Decreased lung volume on the side affected as the fluid displaces the lung tissue. Obscuration of the diaphragm on the affected side because the fluid layers out and hides the diaphragmatic contour. Causes- infection (pneumonia), malignancy, heart failure, or pulmonary embolism. However, definitive diagnosis often requires clinical correlation and additional tests like a thoracentesis to analyze the fluid or further imaging. Reasons for Tracheal Deviation to the Contralateral Side 1. Pleural Effusion: Accumulation of fluid in the pleural space on one side can push the trachea away to the opposite side. 2. Tension Pneumothorax: Air under pressure in the pleural space can cause the lung to collapse and push the trachea away from the affected side. 3. Lung or Pleural Mass: A large tumor in the lung or pleura might exert pressure on the surrounding structures, causing deviation. 4. Lobectomy or Pneumonectomy: Surgical removal of one or more lobes of the lung, or an entire lung, can lead to a shift of the mediastinal structures towards the operated side, pushing the trachea to the opposite side. 5. Lung Collapse (Atelectasis): Loss of volume in a lung or lobe due to obstruction or other causes can result in a mediastinal shift towards the affected side, causing a compensatory shift of the trachea to the opposite side. 6. Large Pleural or Chest Wall Masses: Other masses in the pleural space or chest wall, such as mesothelioma or chest wall tumors, can also push the trachea to one side. 7. Diaphragmatic Hernia: An upward displacement of abdominal contents into the thoracic cavity can push on the lung and mediastinum, resulting in tracheal deviation. 8. Massive Ascites or Hepatomegaly: Severe abdominal swelling due to fluid accumulation or an enlarged liver can push upwards on the diaphragm and indirectly cause the trachea to deviate Clinical Scenario A 50-year-old male smoker presents to the emergency department with cough, fever, and difficulty breathing for the past two days. On examination, there are crackles heard on auscultation of the lungs. A chest X-ray is ordered, shown below. What are the findings and what is the likely diagnosis? A. Diffuse interstitial opacities B. Cavitation C. Pleural effusion D. Hyperinflation E. Consolidation CT chest findings Clinical Scenario A 17 years old patient presents to the emergency department with sudden onset shortness of breath and chest pain. X-rays shown below. What are the findings and Which of the following is a common cause of pneumothorax? A) Lung cancer B) Pulmonary embolism C) Asthma exacerbation D) Trauma E) Congestive heart failure Clinical Scenario A 65-year-old patient arrives at the emergency department with fever, a productive cough, and chest pain. A chest X-ray reveals significant findings. Which of the following findings is most commonly associated with lobar collapse on an X-ray? A) Mediastinal widening B) Cardiomegaly C) Compensatory hyperinflation of unaffected lobes D) Mediastinal shift towards the affected side E) Pleural effusion X-rays findings Medial deviation of the fissure Crowding of the bronchi Opacity of the affected lobe Shift of the mediastinum towards the affected side Clinical Scenario A 55-year-old patient presents to the clinic with a cough and left sided chest pain. A chest X-ray shows a pulmonary mass lesion. Which of the following is the most common cause of a pulmonary mass lesion? A) Pneumonia B) Tuberculosis C) Lung cancer D) Pulmonary embolism E) Pulmonary fibrosis What other questions would you like to ask the patient? Lung Ultrasound Lung ultrasound has become an essential tool for the evaluation of various pulmonary conditions due to its convenience, lack of radiation, and real-time imaging capabilities. It's particularly useful in critical care and emergency settings. Here’s a summary of some key findings: A-Lines: These are horizontal lines parallel to the pleura and equidistant from each other. They indicate the presence of air in the underlying lung and are normally seen in a well-aerated lung. An anechoic or hypoechoic area above the diaphragm with absent A-lines may indicate a pleural effusion B-Lines: These are vertical, comet-tail artifacts that arise from the pleural line and move with respiration. Multiple B-lines can suggest interstitial syndromes, such as pulmonary edema, interstitial pneumonia, or diffuse parenchymal lung disease. Lung Sliding: The sliding of the pleura against one another during respiration, indicating lung expansion and the absence of pneumothorax at that site. Seashore Sign: On M-mode (a type of ultrasound), this pattern indicates normal lung sliding. Barcode or Stratosphere Sign: On M-mode, this pattern suggests the absence of lung sliding, which can be seen in pneumothorax. Consolidation: Appears as a tissue-like, hypoechoic region that may have dynamic air bronchograms (moving air within the bronchi), indicating pneumonia or atelectasis. Pleural Effusion: Appears as an anechoic (black) space above the diaphragm, and can be used to guide thoracentesis. Lung Ultrasound Pulmonary tumour Image explanation Images explanation Patient with SOB, x-ray cheat and CT scan A. Pneumonia B. Pulmonary edema C. Metastasis D. Tuberculosis E. Sarcoidosis Clinical scenarios A 58-year-old woman presents to the emergency room with rapidly progressing shortness of breath and a productive cough over the past 48 hours. She reports a fever and generalized malaise. Her medical history is notable for undergoing chemotherapy for breast cancer. On examination, she is tachypneic with a respiratory rate of 30 breaths per minute, oxygen saturation is 88% on room air, and she has bilateral crackles on auscultation. Her temperature is 38.6°C. Blood work reveals leukocytosis, and a chest X-ray is shown. Arterial blood gas analysis shows marked hypoxemia with a PaO2/FiO2 ratio of less than 200 mmHg. Based on the provided scenario, select the most likely diagnosis: A) Congestive heart failure B) Pneumonia C) Pulmonary embolism D) Acute Respiratory Distress Syndrome E) Chronic Obstructive Pulmonary Disease exacerbation Clinical scenarios Clinical scenario A 35-year-old man presents to the emergency department with left-sided abdominal pain, nausea, and vomiting. He has a lowgrade fever and increased white blood cell count. Physical examination reveals tenderness in the left lower quadrant with rebound tenderness. A CT scan is performed, and the appendix appears inflamed, located on the left iliac fossa. Chest x-ray eas done shown below What is the most likely diagnosis? A. Diverticulitis B. Situs inversus C. Ectopic pregnancy D. Left renal colic E. Sigmoid volvulus Bronchoscopy Indications. Evaluation of persistent cough, hemoptysis (coughing up blood), or unexplained shortness of breath. Diagnosis of lung lesions or tumors seen on chest imaging. Inspection and sampling of tissue in cases of suspected lung infections or lung cancer. Removal of foreign bodies in the airway. Evaluation and treatment of airway obstructions. Contraindications Severe hypoxemia or unstable cardiorespiratory status that cannot be improved with pre-oxygenation or mechanical ventilation. Lack of patient consent or cooperation. Severe coagulopathy or bleeding disorders that cannot be corrected. Recent myocardial infarction or unstable angina. Severe tracheal stenosis, which may not allow passage of the bronchoscope https://youtu.be/uOcnUzC4mZY?feature=shared https://youtu.be/HVgR5moqPZg?feature=shared COPD Summary 1 Summary 2 References Fraser RS, Muller NL, Colman NC, Pare PD. Fraser and Pare's Diagnosis of Diseases of the Chest. 5th ed. Philadelphia, PA: Saunders/Elsevier; 2010. Naidich DP, Bankier AA, MacMahon H, et al. Recommendations for the management of subsolid pulmonary nodules detected at CT: a statement from the Fleischner Society. Radiology. 2013;266(1):304-317. Choi HJ, Lee KY, Kim HJ, et al. CT findings of coronavirus disease 2019 (COVID-19) pneumonia: initial experience in 147 patients. Clin Imaging. 2020;67:74-81. Callister ME, Baldwin DR, Akram AR, et al. British Thoracic Society guidelines for the investigation and management of pulmonary nodules. Thorax. 2015;70 Suppl 2:ii1-ii54. Austin JH, Garg K, Aberle D, et al. Radiologic implications of the 2011 classification of adenocarcinoma of the lung. Radiology. 2013;266(1):62-71. doi:10.1148/radiol.12112008 Kim HJ, Goo JM, Lee KH, et al. Computerized texture analysis of persistent part-solid ground-glass nodules: differentiation of preinvasive lesions from invasive pulmonary adenocarcinomas. Radiology. 2015;275(1):285-295. Wong KT, Antonio GE, Hui DS, et al. Thin-section CT of severe acute respiratory syndrome: evaluation of 73 patients exposed to or with the disease. Radiology. 2003;228(2):395-400. Schabath MB, Massion PP, Thompson ZJ, et al. Differences in patient outcomes of prevalence, interval, and screen-detected lung cancers in the CT arm of the National Lung Screening Trial. PLoS One. 2016;11(11):e0166280.