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HRCT CHEST/TEMPORAL BONE PROTOCOL.pptx
The document outlines the technical aspects and protocols for high-resolution computed tomography (HRCT), focusing on its application in diagnosing lung and temporal bone diseases. It details patient preparation, different scanning positions, technical specifications, and potential artifacts. HRCT is significant for assessing various lung conditions, providing improved visualization while noting increased radiation exposure and image noise as disadvantages.
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HRCT CHEST/TEMPORAL BONE PROTOCOL.pptx
- 1. HRCT TECHNICAL ASPECTSHRCT PROTOCOL Mr.SAMEERAHMADGANAIE ASSISTANTPROFESSOR COPMSADESHUNIVERSITY,BATHINDAPUNJAB151001
- 2. Contents History Objective Purpose Introduction Indications Patientpreparations Technicalaspects HRCTchestprotocol HRCTtemporalboneprotocol Artifactsin HRCT Clinicalapplicationsof HRCT
- 3. History • 1982– Theterm 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 objectiveof HRCT is to detect, characterize, and determine the extent of diseases that involve the lung parenchyma and airways.
- 5. Purpose The mainpurpose of High-resolution computed tomography (HRCT) is to diagnose and monitoring of disease of lung tissue ,airways and the temporal bone.
- 6. Introduction By eliminatingsuperimposition 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 Diffuseinfiltrative lung disease Pulmonary tuberculosis Sarcoidosis Hypersensitivity pneumonitis Langerhans cell histiocytosis Lymphangitic carcinomatosis Silicosis Idiopathic pulmonary fibrosis Usual interstitial pneumonitis (UIP)
- 8. PATIENT PREPARATION • Fastingis 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 topatient 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 canbe 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 • Itis helpful to distinguish between complex pleural and pulmonary pathological conditions.
- 14. POSITIONING AND CENTERING Patientorientation: Supine Feet first
- 15. PROTOCOL FOR HRCTCHEST. 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 FILTERlung enhancement COLLIMATION 640.625 FOV 350 MATRIX SIZE 768768 CONTRAST NO RECON IRS 0.6/0.33 RECONSTRUCTION AXIAL , CORONAL , SAGITTAL
- 17. Miliary tuberculosis. HRCTimage shows numerous nodules a few millimeters in diameter distributed randomly through both lungs.
- 18.
- 19. HRCT TEMPORAL BONE Indication •Trauma • Fracture • Internal auditory canal • Mastoid air cells • Trauma in middle ear • Facial paralysis
- 20. POSITIONING AND CENTERING Patientorientation: Supine Head first Anatomical landmark: glabella
- 21.
- 22. PROTOCOL FOR TEMPORALBONE POSITION SUPINE SCANO DUAL SLICE THICKNESS 1mm TABLE INCREMENT 1mm MATRIX SIZE 512512 FILTERS BONE SHARP CONTRAST NO AREA COVERAGE TEMPORAL BONE
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- 24. Artifact in HRCT Streakartifact : 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 ofvery small lesions. Eg: small metastatic lesions, ILD. DISADVANTAGES • Increased image noise. • Radiation dose is more.
- 27. Clinical Application ofHRCT 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.
Editor's Notes
- #7 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)