# Clinical Cases: Chest Imaging ## Case 1: Lobar Pneumonia with Air Bronchograms ### Patient Demographics - **Age:** 67 years - **Sex:** Male ### Chief Complaint Productive cough and fever for 4 days ### Presenting Symptoms The patient presents with a 4-day history of productive cough with rust-colored sputum, fever up to 39.4C, and progressive shortness of breath. He reports right-sided pleuritic chest pain that worsens with deep inspiration. He has a 40 pack-year smoking history and continues to smoke. He denies recent travel, sick contacts, or immunosuppression. ### Physical Exam Findings - **Vital Signs:** Temp 38.9C, BP 138/82 mmHg, HR 102 bpm, RR 24/min, SpO2 91% on room air - **General:** Ill-appearing male in mild respiratory distress - **Pulmonary:** Decreased breath sounds over right lower chest, dullness to percussion at right base, egophony and bronchial breath sounds over right lower lobe, increased tactile fremitus - **Cardiovascular:** Tachycardic, regular rhythm, no murmurs ### Imaging Findings and Interpretation **Chest Radiograph (PA and Lateral):** - Dense consolidation involving the right lower lobe - Air bronchograms visible within the consolidation (air-filled bronchi surrounded by airless lung) - Silhouette sign: Right hemidiaphragm is obscured (consistent with right lower lobe involvement) - Right heart border remains visible (excludes middle lobe involvement) - No pleural effusion visible - No mediastinal widening - Cardiothoracic ratio within normal limits **Radiographic Interpretation:** The presence of lobar consolidation with air bronchograms in a febrile patient with productive cough is classic for bacterial pneumonia. The preservation of the bronchial tree (air bronchograms) indicates the airways are patent and the process is alveolar filling rather than atelectasis. The right heart border visibility with right hemidiaphragm obscuration confirms right lower lobe localization based on the silhouette sign. ### Diagnosis Community-acquired pneumonia, right lower lobe - likely Streptococcus pneumoniae given lobar distribution and clinical presentation ### Management 1. Hospitalization given hypoxemia and severity (CURB-65 score: 2) 2. Supplemental oxygen to maintain SpO2 >92% 3. Empiric antibiotics: Ceftriaxone 1g IV daily + Azithromycin 500mg IV daily 4. Blood cultures and sputum culture obtained before antibiotics 5. Urinary pneumococcal and legionella antigens 6. Follow-up chest radiograph in 6-8 weeks to document resolution and exclude underlying malignancy given smoking history ### Radiological Image ![Lobar Pneumonia with Air Bronchograms](case_01_image.jpg) **Image Description:** Chest radiograph demonstrating right lower lobe consolidation with visible air bronchograms, indicating alveolar filling while bronchi remain patent. The right hemidiaphragm is obscured (silhouette sign), confirming lower lobe involvement. **Source:** Wikimedia Commons - "Chest X-ray in influenza and Haemophilus influenzae, with areas of consolidation" **URL:** https://commons.wikimedia.org/wiki/File:Chest_X-ray_in_influenza_and_H_influenzae.jpg **License:** Creative Commons Attribution 2.0 Generic --- ## Case 2: Pulmonary Embolism - CT Pulmonary Angiography ### Patient Demographics - **Age:** 45 years - **Sex:** Female ### Chief Complaint Sudden onset shortness of breath and pleuritic chest pain ### Presenting Symptoms The patient presents with acute onset of dyspnea and right-sided pleuritic chest pain that began 6 hours ago. She reports a 12-hour flight from Australia 5 days ago and has been relatively sedentary since returning due to jet lag. She has a history of obesity and takes oral contraceptive pills. She describes the dyspnea as sudden and severe, with mild hemoptysis. ### Physical Exam Findings - **Vital Signs:** BP 108/72 mmHg, HR 118 bpm, RR 26/min, SpO2 88% on room air, Temp 37.4C - **General:** Anxious, tachypneic female in moderate respiratory distress - **Pulmonary:** Clear to auscultation bilaterally, no wheezing or crackles - **Cardiovascular:** Tachycardic, loud P2, JVP elevated at 12 cm - **Extremities:** Right calf swelling and tenderness, positive Homans sign ### Imaging Findings and Interpretation **CT Pulmonary Angiography:** - **Pulmonary Arteries:** Large filling defect straddling the main pulmonary artery bifurcation (saddle embolus) - Additional bilateral segmental and subsegmental emboli in both lower lobes - "Polo mint sign" visible on axial images where emboli are surrounded by contrast - **Right Heart:** RV/LV ratio 1.4 (elevated, normal <1.0), indicating right ventricular strain - Reflux of contrast into the hepatic veins and IVC indicating elevated right heart pressures - **Lung Parenchyma:** Peripheral wedge-shaped opacity in right lower lobe (Hampton hump - pulmonary infarct) - No pleural effusion - **Incidental:** No evidence of aortic dissection **Wells Score (Pre-test Probability):** - Clinical signs of DVT: 3 points - PE most likely diagnosis: 3 points - Heart rate >100: 1.5 points - Immobilization/surgery: 1.5 points - **Total: 9 points (high probability)** ### Diagnosis Massive/submassive pulmonary embolism (saddle embolus) with right ventricular strain and pulmonary infarction, associated lower extremity DVT ### Management 1. Immediate anticoagulation with IV heparin bolus and infusion 2. ICU admission for hemodynamic monitoring given RV strain 3. Echocardiography to confirm RV dysfunction 4. Consider systemic thrombolysis or catheter-directed therapy given RV strain (submassive PE) 5. Lower extremity duplex ultrasound to confirm DVT 6. Troponin and BNP for prognostication 7. Transition to DOAC (rivaroxaban or apixaban) after stabilization 8. Hypercoagulability workup after acute treatment (consider Factor V Leiden, antiphospholipid syndrome) 9. Minimum 3 months anticoagulation; consider extended duration given unprovoked nature ### Radiological Image ![CT Pulmonary Angiography Pulmonary Embolism](case_02_image.jpg) **Image Description:** CT pulmonary angiography demonstrating a large pulmonary embolism with filling defects visible within the pulmonary arteries. The "polo mint sign" shows central thrombus surrounded by contrast when viewed in cross-section. **Source:** Radiopaedia - Educational image demonstrating pulmonary embolism findings **URL:** https://radiopaedia.org/articles/pulmonary-embolism **License:** Educational use per Radiopaedia terms (Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported) --- ## Case 3: Usual Interstitial Pneumonia (UIP) Pattern ### Patient Demographics - **Age:** 71 years - **Sex:** Male ### Chief Complaint Progressive dyspnea on exertion over 2 years ### Presenting Symptoms The patient reports gradually worsening shortness of breath that initially occurred only with strenuous activity but now limits him to walking one block on flat ground. He has a dry, non-productive cough that has persisted for over a year. He denies fevers, weight loss, hemoptysis, or known exposures to asbestos, birds, or organic dusts. He is a former smoker with a 20 pack-year history, quit 15 years ago. ### Physical Exam Findings - **Vital Signs:** BP 126/78 mmHg, HR 82 bpm, RR 18/min at rest, SpO2 94% on room air (drops to 86% with ambulation) - **General:** Well-appearing male with mild clubbing of fingernails - **Pulmonary:** Bilateral fine inspiratory crackles ("velcro" crackles) at lung bases, no wheezes - **Cardiovascular:** Regular rate and rhythm, no peripheral edema ### Imaging Findings and Interpretation **High-Resolution CT (HRCT) Chest:** - **Distribution:** Bilateral, peripheral, and basal predominant fibrotic changes - **Honeycombing:** Subpleural clustered cystic airspaces with thick walls (3-10mm diameter) at both lung bases - pathognomonic for UIP pattern - **Traction bronchiectasis:** Dilated airways within areas of fibrosis - **Reticulation:** Interlobular and intralobular septal thickening - **Minimal ground-glass opacity:** Limited areas of ground glass, consistent with UIP rather than NSIP - **No features suggesting alternative diagnosis:** No upper lobe predominance, air trapping, or centrilobular nodules that would suggest hypersensitivity pneumonitis **Pattern Classification:** The combination of basal-peripheral predominant honeycombing, traction bronchiectasis, and reticulation WITHOUT features suggesting alternative diagnosis meets criteria for a DEFINITE UIP pattern on HRCT. Per 2018 ATS/ERS guidelines, this imaging pattern in the appropriate clinical context is diagnostic for idiopathic pulmonary fibrosis without need for surgical lung biopsy. ### Diagnosis Idiopathic Pulmonary Fibrosis (IPF) based on definite UIP pattern on HRCT in appropriate clinical context ### Management 1. Multidisciplinary discussion confirming diagnosis (pulmonology, radiology, pathology) 2. Pulmonary function tests (expected restrictive pattern with reduced DLCO) 3. Antifibrotic therapy: Pirfenidone or Nintedanib to slow disease progression 4. Supplemental oxygen for exertional hypoxemia 5. Pulmonary rehabilitation program 6. Lung transplant evaluation given progressive disease (age-appropriate candidate) 7. Vaccinations: Pneumococcal and annual influenza 8. Avoid known exacerbation triggers 9. Palliative care involvement for symptom management and advance care planning ### Radiological Image ![HRCT UIP Pattern](case_03_image.jpg) **Image Description:** High-resolution CT of the chest demonstrating the usual interstitial pneumonia (UIP) pattern with basal-predominant honeycombing (clustered cystic airspaces with thick walls), traction bronchiectasis, and reticulation. This pattern is diagnostic for idiopathic pulmonary fibrosis. **Source:** Wikimedia Commons - "CT scan of idiopathic pulmonary fibrosis" **URL:** https://commons.wikimedia.org/wiki/File:IPF_amiodarone.JPG **License:** Creative Commons Attribution-Share Alike 3.0 Unported --- ## Learning Points 1. **Air Bronchograms and the Silhouette Sign:** Air bronchograms indicate alveolar consolidation with patent airways, characteristic of pneumonia. The silhouette sign localizes pathology based on which borders are obscured - right hemidiaphragm obscuration indicates right lower lobe involvement. 2. **CT Pulmonary Angiography Protocol:** CTPA requires precise bolus timing to maximize pulmonary arterial opacification. Key findings include intraluminal filling defects, the "polo mint sign," and secondary signs of RV strain that influence management decisions. 3. **UIP Pattern Recognition:** The combination of honeycombing, traction bronchiectasis, and basal-peripheral predominant fibrosis without features suggesting alternative diagnoses constitutes a definite UIP pattern, which is diagnostic for IPF without biopsy. 4. **Fleischner Society Guidelines:** For pulmonary nodule management, size, morphology, and patient risk factors determine follow-up intervals. HRCT patterns guide interstitial lung disease diagnosis through recognition of specific imaging features.