334 Lecture 2 chest S21 notes

Chest Imaging Analysis Guidelines

Page 1: General Requirements

• Facility Identification Requirements

  • Ensure visible identification as per facility guidelines.

• Side Marker

  • Use a right or left marker on the projection; avoid superimposition over the VOI (volume of interest).

• Radiation Protection

  • Follow good practices for radiation safety.

• Image Clarity

  • Key structures like lung markings, diaphragm, heart borders, hilum, greater vessels, and bony outlines should be sharply defined.

  • Adequate contrast resolution to show: thoracic vertebrae, mediastinal structures, vascular markings, fluid-air levels, and monitoring apparatus.

  • No quantum mottle (graininess) or saturation is present.

  • Minimize scatter radiation.

• Artifacts

  • No preventable artifacts (e.g., undergarments, jewelry, external monitoring devices).

Standard Imaging Protocols

• Technical Data

  • PA Chest: kV 110-125, Grid both outside, SID 72 inches.

  • Lateral Chest: kV 110-125, Grid Center, SID 72 inches.

  • AP Mobile: kV 110-125, AEC 3, SID 50-60 inches.

  • AP Supine in Bucky: kV 80-100, Grid both outside, SID 50-60 inches.

  • Lateral Decubitus: kV 110-125, Grid Center, AEC 3, SID 72 inches.

  • AP Axial (Lordotic): kV 110-125, Grid both outside, SID 72 inches.

• Positioning Considerations

  • Use proper positioning to ensure accurate imaging outcomes.

Page 2: Pediatric Imaging Guidelines

• Technical Data for Neonates to Children

  • Neonates: AP 70-80 kV, 1 mAs, SID 50-60 inches.

  • Infants: AP 75-85 kV, 1.5 mAs; Cross-table lateral 80-90 kV, 3 mAs.

  • Children: AP 75-85 kV, 2 mAs; Cross-table lateral 85-110 kV, Grid Center, SID 72 inches.

• Positioning Techniques

  • Ensure proper SID (72 in) to reduce magnification of cardiac and lung details.

  • Confirm proper patient ventilation for second full inspiration.

  • Consider pathology (e.g., pneumothorax, pneumectomy, pleural effusion).

• Chest Devices, Tubes, Lines, and Catheters

  • Familiarize with routine procedures for erect PA, lateral, mobile AP, and pediatric chests.

Page 3: PA Chest Projection Analysis

• Technical Features

  • Thoracic vertebrae visible through the heart and mediastinal structures.

  • Symmetrical lung fields; equal distance from the vertebral column to sternal ends and lengths of posterior ribs.

• Check for Rotation

  • Evaluate distances between vertebrae and sternal ends; symmetrical alignment needed.

  • Identify scoliosis via varying distances in lung edges; ensure scapulae are positioned correctly.

Page 4: Midcoronal Plane and Tilting

• Positioning for Clarity

  • Correct alignment maintains lung and heart without foreshortening.

• Identifying Tilt

  • Recognize anterior tilt (foreshortened) versus posterior tilt (foreshortened with less visibility).

  • Monitor for vertical dimension increase through full inspiration.

• Poor Inspiration Factors

  • Acknowledge obstacles (disease, pregnancy, obesity) affecting lung aeration.

Page 5: Understanding Rotational Changes

• Anatomical Alignment

  • Midcoronal plane perpendicular to IR shows separation in posterior ribs due to magnification.

  • Distinguish left from right lung by evaluating gastric air bubble and heart shadow positioning.

• Midsagittal Plane

  • Ensure superimposition is monitored for diverging beams and correct positioning of hemidiaphragms.

Page 6: Supine or Portable AP Chest Projection

• General Projection Characteristics

  • Recognize thoracic vertebrae visibility through mediastinal structures and symmetrical lung fields.

  • Ensure clavicles and scapulae are properly positioned outside the lung field.

• CR Placement

  • Central ray (CR) directed to T7 (4 inches below the jugular notch) ensures visibility of both lung apices.

• Lung Aeration

  • A minimum of 9 posterior ribs should be visualized above diaphragm; assess body habitus for IR placement.