Chest Radiograph: Cardiac Perspective

Chest Radiograph

• Congenital heart disease: Abnormal
• Acquired heart disease: Usually Normal

PA view

• Patient upright and breath held in full end inspiration.

Heart size

• AP > PA view (as heart further from film in AP view).

Normal Chest Radiograph

Cardiac silhoutte (PA view)

Cardiac silhoutte (Lateral view)

Pulmonary vasculature

Heart size

• Transverse cardiac diameter: \( \leq \) 16 cm in males and \( \leq \) 15 cm in females.
• Cardiothoracic ratio: \( \leq \) 50%.

Analysis of Chest Radiograph

• Cardiac shadow: ANATOMIC ASPECT.
• Pulmonary vasculature: PHYSIOLOGIC ASPECT.
• ORDER OF ANALYSIS
  • Technical consideration
    • Overexposed: Pulmonary oligemia.
    • Underexposed: Increased pulmonary vasculature.
    • In expiration: Diffuse lung disease.
    • Rotated film: Abnormal heart size.
  • Skeletal system
    • Pectus excavatum: Straightening of left heart border.
    • Straight back syndrome: Cardiomegaly.
    • Scoliosis.
    • Sternal depression & straight back syndrome: Associated with MVP.
    • Down syndrome: 11 pair of ribs & VSD.
    • Rib notching: Coarctation of aorta, pulmonary atresia, vena caval syndrome, Blalock Taussig Shunt.
  • Upper abdomen
    • Gall stones, histus hernia in chest pain.
    • Situs.
  • Lungs
  • Cardiac shadow

Lungs

• Look for co-existing lung diseases.
• Pulmonary vasculature
  • Increased
    • Pulmonary venous hypertension (PVH), PAH, pulmonary over-circulation.
  • Decreased
    • Oligemia.
  • Normal
    • DOESNOT EXCLUDE SIGNIFICANT MYOCARDIAL DISEASE, MILD VALVULAR DISEASE OR SMALL INTRA-CARDIAC SHUNT.
  • Uneven

Abnormalities of Pulmonary circulation

1. Pulmonary venous hypertension (Close correlation exists between PCWP and extent of PVH in untreated patients)
   • Stage 1 (< 12 mmHg)
     • Normal findings.
   • Stage 2 (12 - 18 mmHg)
     • Pulmonary vein dilation. D/D: Basal emphysema.
       • Upper lobe diversion.
   • Stage 3 (18 - 22 mmHg)
     • Interstitial edema. D/D: Non Cardiogenic Pulmonary Edema.
       • Perihilar haze.
       • Peribronchial cuffing.
       • Kerley B lines - Interlobular edema.
       • Kerley A lines - Thickened inter lobular septum.
   • Stage 4 (> 22 mmHg)
     • Alveolar edema. D/D: Non Cardiogenic Pulmonary Edema.
       • Perihilar.
       • Can be patchy/asymmetrical.
       • Pleural effusion.
   • Chronic PVH (Causes)
     • PAH.
     • Pulmonary hemosiderosis (bileteral, diffuse, granular).
     • Pulmonary ossicles (Calcified, basal, nodules upto 1 cm).
2. Pulmonary arterial hypertension (PAH)
   • Definition: PAsysP > 30 mmHg.
   • Features:
     • Central PA increased (D/D: Hilar lymphadenopathy - lymphadenopathy is more lobular).
     • Peripheral PA decreased.
     • Calcification of central PA.
3. Pulmonary over-circulation
   • Pulmonary:systemic circulation < 2:1
     • No changes.
   • Pulmonary:systemic circulation \( \geq \) 2:1
     • Central PA increased.
     • Peripheral PA increased (extending > lateral 1/3rd of lung field).
     • LOOK FOR CYANOSIS:
       • Present: Bidirectional shunt.
       • Absent: Left to right shunt.
4. Bronchial circulation
   • Severe RV outflow obstruction.
5. Pulmonary oligemia
   • TOF.
   • Cardiac tamponade (Restricted filling of RV).
6. Uneven vascularity
   • Pulmonary disease (Commonest cause).
   • Cardiogenic causes
     • Pulmonary thrombo-embolism.
     • Shunt surgery.
     • Pulmonary arterial stenosis.
     • Pulmonary AV fistula.

Cardiac shadow

1. Systemic veins
   • SVC
     • Increased flow: Supra-cardiac anomalous pulmonary vein return.
     • Increased pressure: Rt HF, Tricuspid valvular disease, Cardiac tamponade, Constrictive pericarditis.
     • Obstruction: Mediastinitis, Mediastinal tumor.
   • Azygous vein
     • IVC obstruction.
   • IVC
     • Rt HF.
     • TR/TS.
2. Right atrium dilation
   • Increased prominence of lower half of right heart border.
3. Right ventricle dilation
   • PA view
     • Apex outwards and upwards.
     • Gross dilation: forms Lt heart border and bump just below pulmonary trunk.
   • Lateral view
     • Decreased retro-sternal space.
   • Pulmonary trunk
     • Increased
       • PAH: associated peripheral pruning.
       • Pulmonary over-circulation: associated pulmonary plethora.
       • Post stenotic/idiopathic: associated normal pulmonary vasculature.
     • Decreased
       • TOF.
       • Pulmonary atresia.
     • Absent
       • Corrected transposition of Great Vessels.
4. Left atrium dilation
   • Increased carinal angle.
   • Right sided double density (marked dilation: can form right border).
   • Denting of esophagus (Lateral view, Barium swallow).
   • Straightening/convexity of left atrial appendage.
5. Left ventricle
   • Hypertrophy
     • Increased Lt heart border convexity.
   • Dilatation
     • PA: Apex outwards and downwards, increased cardio-thoracic ratio.
6. Aorta
   • Increased Ascending Aorta
     • Post-stenotic dilation.
     • Aneurysm.
   • Increased Aortic Knuckle
     • Aneurysm.
     • PDA.
     • Pulmonary atresia.
   • Increased Descending Aorta
     • Aneurysm.
   • Increased Thoracic Aorta
     • Systemic hypertension.
     • Aortic regurgitation.
7. Pericardium
   • Pericardial effusion
     • Non-specific globular enlargement.
     • Normal pulmonary vasculature.
   • Congenital absence of pericardium
     • Left displacement of cardiac shadow.
8. Cardiac calcification
   • Fluoroscopy better than Plain Films.
   • VALVE CALCIFICATION
     • Aortic valve
       • PA view: over spine (may be obscured)
       • Lateral view: (see figure)
     • Mitral valve
       • PA view: Lt side of spine
       • Lateral: (see figure)