HRCT Protocol Guide for Lung and Temporal Bone Exams
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This presentation includes High-resolution computed tomography (HRCT) of the Chest and Temporal bone. Objective of HRCT. Artefacts in HRCT. Clinical applications of HRCT. Advantages of HRCT. Disadvantages of HRCT. Positioning and Centering.
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HRCT Protocol Guide for Lung and Temporal Bone Exams
- 1. HRCT TECHNICAL ASPECTS HRCT PROTOCOL Mr.SAMEERAHMADGANAIE ASSISTANTPROFESSOR COPMSADESHUNIVERSITY,BATHINDAPUNJAB151001
- 2. Contents History Objective Purpose Introduction Indications Patientpreparations Technicalaspects HRCTchestprotocol HRCTtemporalboneprotocol Artifactsin HRCT Clinicalapplicationsof HRCT
- 3. History • 1982– The term HRCT was first used by TODO et. Al • 1985 – Nakata et.al and Naidich et.al published first report on HRCT.
- 4. Objective The main objective of HRCT is to detect, characterize, and determine the extent of diseases that involve the lung parenchyma and airways.
- 5. Purpose The main purpose of High-resolution computed tomography (HRCT) is to diagnose and monitoring of disease of lung tissue ,airways and the temporal bone.
- 6. Introduction By eliminating superimposition of structures, computed tomography (CT) allows for a better assessment of the type, distribution, and severity of Parenchymal abnormalities. HRCT is a technique which allows us for better evaluate these conditions. It is usually done for chest and temporal bone. • Use of thin section CT images (0.625 to 2 mm slice thickness) often with a high-spatial-frequency
- 7. Indication Chronic lung disease Diffuse infiltrative lung disease Pulmonary tuberculosis Sarcoidosis Hypersensitivity pneumonitis Langerhans cell histiocytosis Lymphangitic carcinomatosis Silicosis Idiopathic pulmonary fibrosis Usual interstitial pneumonitis (UIP)
- 8. PATIENT PREPARATION • Fasting is not required. • Patient is should remove radio opaque materials (chain and other neck ornaments ) from the region of interest. • Pacemaker is not contraindicated. • Patient is asked to change to hospital gown.
- 9. •Proper instruction to patient leads to successful HRCT scan. •Breath holding techniques •Routine HRCT during suspended full inspiration. •It also reduces motion Artifact Technical aspects
- 10. HRCT CHEST It can be done in three position 1.Antero posterior (AP) i.e. Supine 2.Postero anterior (PA) i.e. Prone 3.Lateral decubitus
- 11. SUPINE HRCT Bronchiectasis Diffuse infiltrative lung disease Scan direction from down to up
- 12. PRONE POSITION • Atelectasis (lack of gas exchange within the alveoli) • It is done when posterior lung base is area of suspicion. ex – Asbestosis or Idiopathic pulmonary fibrosis. • It is helpful to Increase aeration to the area.
- 13. LATERAL DECUBITUS • It is helpful to distinguish between complex pleural and pulmonary pathological conditions.
- 14. POSITIONING AND CENTERING Patient orientation: Supine Feet first
- 15. PROTOCOL FOR HRCT CHEST. PROTOCOL CHEST HELICAL PATIENT POSITION Feet First SCANO AP180 degree START LOCATION Apex of lung END LOCATION Costophrenic angle SLICE THICKNESS 1mm TABLE INCREMENT 10mm KV 120 Kvp
- 16. Cont…… mA 365 mA FILTER lung enhancement COLLIMATION 640.625 FOV 350 MATRIX SIZE 768768 CONTRAST NO RECON IRS 0.6/0.33 RECONSTRUCTION AXIAL , CORONAL , SAGITTAL
- 17. Miliary tuberculosis. HRCT image shows numerous nodules a few millimeters in diameter distributed randomly through both lungs.
- 19. HRCT TEMPORAL BONE Indication • Trauma • Fracture • Internal auditory canal • Mastoid air cells • Trauma in middle ear • Facial paralysis
- 20. POSITIONING AND CENTERING Patient orientation: Supine Head first Anatomical landmark: glabella
- 21. PLANNING…
- 22. PROTOCOL FOR TEMPORAL BONE POSITION SUPINE SCANO DUAL SLICE THICKNESS 1mm TABLE INCREMENT 1mm MATRIX SIZE 512512 FILTERS BONE SHARP CONTRAST NO AREA COVERAGE TEMPORAL BONE
- 24. Artifact in HRCT Streak artifact : radiate from the edges of a sharply marginated, high contrast structures (bronchial walls, ribs or vertebral bodies)
- 25. Motion Artifact Pulsation or “ star” artifacts are commonly visible at the left lung base. Can be reduced by ECG gating.
- 26. ADVANTAGES • Diagnosis of very small lesions. Eg: small metastatic lesions, ILD. DISADVANTAGES • Increased image noise. • Radiation dose is more.
- 27. Clinical Application of HRCT To detect diffuse lung disease To investigate patient with unexplained severe obstructive airway To investigate patient with hemoptysis To guide the type and style of lung biopsy
- 28. Thank you
Editor's Notes
- It is often used for anything and everything to do with “high resolution”. Resolution : Means ability to resolve small object that are close together ,as separate form. Actual meaning A scan performed using high- spatial frequency algorithm to accentuate the contrast between tissue of widely differing densities, eg., - air & vessels (lung) - air & bone (temporal & paranasal sinus)