Computed Tomography• Numerous protocols/techniques depending on clinical history• Helical/spiral versus high resolution• Contrast – Renal failure – Allergy
Computed Tomography• Role of CT – Main further investigation for most CXR abnormality (eg nodule/mass) or to exclude disease with normal CXR – Main investigation for certain scenarios (PE, dissection, trauma)
MRI• Multiple planes• No radiation• Common Indication – Pancoast tumour – Brachial plexus – Cardiac – Vascular (aorta)• Usually targeted examination (unlike CT) Coronal
Nuclear Medicine• Variety of tests: functional rather than anatomic• V/Q specific to chest imaging• Others: bone scan, gallium, WBC etc.
Ultrasound• Limited use in thorax (non cardiac) due to air in lungs• Assess pleural effusions• Mainly used for procedures
Chest Radiographs• PA (posterior to anterior) and Lateral (left) – Minimizes magnification of heart (heart closest to film)• Portable (nearly always AP) – Supine or Erect• Specialized Views – Lordotic – Lateral decubitus (for effusions, pneumothorax)
Lordotic View Better assess apices without bone overlap
1 1: Adequate penetration of 4 a the mediastinum-is the a thoracic spine seen? 2: Has the patient taken a good inspiratory effort? About 8-107 posterior thoracic ribs should be seen through the lungs 3: Is there any rotation of the chest? Assessed by checking 10 the upper thoracic spinous process (oval) in relation to the medial ends of the clavicles (lines ‘a’) - this CXR is rotated to left
Chest Radiograph: Approach and Normal AnatomyTHERE IS NO ONE APPROACH: BE SYSTEMATIC• Bone and Soft Tissue including abdomen• Heart• Mediastinum-aorta, trachea• Hila• Pulmonary Vasculature• Lungs• Pleura
Sequence For X Ray Reading 5 Ds• Detect• Describe• Differential Diagnosis• Discuss• Diagnosis
Pulmonary Artery Left LungCoronal Image PA Lung “markings” are pulmonary arteries and veins
• Spine Sign: Lungs posteriorly should get Scapula darker as you go down inspexp more inferiorlyRetrosternal Airspace Hilum IVC Pulmonary Vessels
Case: (Look at the trachea)Trachea isDeviated bylarge mass(goiter)
Abnormal Cases• Bone• Cardiovascular• Airspace Disease including Silhouette Sign• Interstitial Disease and Pulmonary Edema• Atelectasis• Pulmonary Nodule• Pleura and Diaphragm• Mediastinal Mass
ACINAR PATTERN (CXR) Radiology: Round or elliptical ill-defined 4-8mm opacities in lungMicroscopic: Portion of lung distal to terminal bronchial (respiratory bronchial, alveolar duct, alveolar sac and alveoli) is the acinus CXR close up of acinar pattern
ACINAR PATTERN (CT SCAN)Round or elliptical ill-defined 4-8mm opacities in lung CT scan of right upper lobe showing typical acinar pattern (arrow)
AIR BRONCHOGRAMAir containing bronchus peripheral to the hilum surrounded by airless lung CXR CT Scan Air Bronchogram
NODULAR PATTERN Collection of innumerable small, linear and nodular opacities together producing a net with small superimposed nodules. CTCXR Close up of nodular pattern
EMPHYSEMA: Abnormally expanded air spaces distal to terminal bronchiole with destruction of walls of involved air spaces..BULLA: Gas containing avascularity of lung measuring 1cm or more in diameter, 1mm thickness Bulla CT of bulla
Pneumonia (consolidation)• Air bronchograms would confirm an alveolar process.• The lung volume should not be lost (may even be increased).• Usually all radiographic abnormalities should disappear after 6 weeks of appropriate antibiotic therapy.
Consolidation and follow-up X-rays• Recommendations are, repeat film at 1, 3 and 7 days to check for the development of complications.• Resolution of the X-ray signs always lags behind the clinical findings• The X-ray should therefore be repeated 4 weeks later to check for resolution.• If there is persistent consolidation at this stage, further investigation is necessary to exclude an obstructive lesion.
SIGNS OF COLLAPSEDIRECT SIGNS:• Displacement of fissures• Loss of aeration• Vascular & bronchial signsINDIRECT SIGNS:• Mediastinal & Hilar displacement• Elevation of Hemidiphragm• Compensatory hyperinflation
hugeptx Tracheal Deviation Collapsed Right Lung What would you do with this patient?Tension Pneumothorax: Requires chest tube
Causes of a pneumothorax• Spontaneous• Iatrogenic/trauma,• Obstructive lung disease, e.g. asthma, COPD• Infection, e.g. pneumonia, tuberculosis Cystic fibrosis• Connective Tissue Disorders, e.g. Marfan’s, Ehlers-Danlos
Causes of single coin lesions• Benign tumor, e.g. hamartoma• Malignant tumor, e.g. bronchial carcinoma, single secondary• Infection, e.g. pneumonia, abscess, tuberculosis, hydatid cyst• Infarction• Rheumatoid nodule
Severe heart failure• Severe pulmonary edema gives confluent alveolar shadowing which spreads out from the hilum giving a bats wing appearance.• If this is the cause of generalized shadowing then upper lobe blood diversion and Kerley B lines should be present.• In pulmonary edema hilum may appear distended and the vessels close to the hilum may be blurred.
Severe heart failure vs. non- carcinogenic pulmonary edema• In non-cardiogenic pulmonary edema the heart size is likely to be normal and there will not necessarily be sparing of the peripheries.
Causes of Bronchiectasis• Structural, e.g. Kartagener syndrome,• obstruction (carcinoma, foreign body)• Infection, e.g. childhood pertussis or measles, tuberculosis, pneumonia• Immune, e.g. hypogammaglobulinaemia, allergic bronchopulmonary aspergillosis• Metabolic, e.g. cystic fibrosis• Idiopathic to stasis