Diagnostic Testing

    Table of contents




    Chest Xray

    • CXR Conditions with upper lobe prominence:
      • Sarcoidosis
      • Silicosis
      • Langerhan Cell Histiocytosis
      • Cystic Fibrosis
      • Reactivation of TB
      • (Chronic hypersensitivity pneumonitis)
    • CXR with lower lung zones
      • Idiopathic pulmonary fibrosis
      • Cryptogenic Organizing Pneumonia
      • Asbestosis
      • Heart Failure
    • Response to treatment:
      • Pneumonia
      • Heart Failure
      • Pneumothorax


    Chest CT

    • Indicated for:
      • ILD
      • Bronchiectasis
      • Pulmonary Nodules (small)
      • Cancer, signs of spread
      • Pulmonary Embolus
      • Lymphadenopathy
      • Characterizing pulmonary nodules (calcifications etc..)
    • Contrast CT for:
      • Helps see large blood vessels.
      • Identify metastasis to liver/adrenals. 
      • Vascular concerns (dissection, PE)
    • Differential for "Ground Glass"
      • Atypical Infections
        • Viruses (HSV, CMV)
        • Fungi (PCP, Aspergilosis [halo sign w/ surrounding groundglass])
      • Chronic Interstitial Diseases
        • Eosinophilic Pneumonia
        • Idiopathic Interstitial Pneumonia (UIP/NSIP/COP etc..)
        • Sarcoidosis
      • Alveolar Diseases
        • Pulmonary Edema (ARDs, Heart failure)
        • Pulmonary Hemorrhage
        • Hypersensitivity Pneumonitis


    PET CT

    • PET combined with CT
      • Higher Sn and Sp when done together.
      • Expensive, but saves pts from unnecessary surgery.
    • Using for staging lung cancers.
    • FDG (Flurodeoxy glucose) - see if mass is metabolically active.
      • If does not light up does not exclude Ca, but makes it less likely.

    PET Scan

    • Sp 90%, Sp 85% for mediastinal spread.. (30 and 40% for standard CT).
    • Not useful for <1cm diameter
    • False Positive PET:
      • Infection (TB, fungal, other atypical)
      • Sarcoidosis.
    • False Negative PET:
      • Low grade variants of adenocarcinoma
      • Carcinoid (both metabolically slow).



    • Insert the scope and collect samples.
    • Good way to visualize and biopsy central pulmonary lesions.
    • Radial US and electromagnetic navigation tools. (tells bronchoscopist which way to go)
    • Endobronchial ultrasound... easier to get tissue that was formerly only done via mediastinoscopy.
    • Reasons to do Bonchoscopy:
      • Tissue Samples
        • Under electromagnetic guidance or endobronchial ultrasound (EBUS)
        • Can sample: endobronchial, mediastinal, and peripheral nodes
          • Peripheral nodules are possible to biopsy if >2cm in diameters.  (<2cm likelihood is low <50% success) May need CT-guided percutaneous biopsy.
      • Broncho-Alveolar Lavage
        • Helps with diagnosis, to obtain cultures
        • Normally see alveolar macrophages (95%)
          • If other cells can help diagnosis. (i.e. lymphocytosis, eosinophilia, neutrophilia).
      • Therapeutic
        • Clearance of secretions.
        • Foreign bodies.
        • Palliative (if airway tumor blocking airway), can debulk tumors and sometimes put stents.
    • Safety:
      • Risk is low.
      • Discuss bleeding, sedation medications, cardiac arrest if limited lung reserve, biopsies can cause pneumothorax.
      • Very rare to die from bronchoscopy 1 in 1000.
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