Patient Image Optimization & Image Quality Factors

Body Habitus

• General size and shape of a patient, influencing radiographic technique.
• Types:
  • Sthenic: Average patient.
  • Hyposthenic: Thin, healthy.
  • Hypersthenic: Large frame, often overweight (Bariatric).
  • Asthenic: Small, frail.

Thickness of Part

• Thicker parts require more radiation to penetrate.
• Measured using instruments; BMI (Body Mass Index) is a consideration.
• Muscle weighs more than fat, influencing technique adjustments.

Body Composition

• Mass density differences in body tissue affect technique.
• Contrast studies require increased technique.

Radiolucent vs. Radiopaque

• Radiolucent: Attenuates few X-rays, appears black (e.g., lung tissue).
• Radiopaque: Absorbs X-rays, appears white (e.g., bones).

Pathology

• Influences radiographic technique based on:
  • Type
  • Size
  • Composition
• Examples:
  • Radiolucent (Destructive): Active tuberculosis, atrophy, bowel obstruction.
  • Radiopaque (Constructive): Degenerative arthritis, aortic aneurysm, ascites.

Image Quality Factors

• Include spatial resolution, contrast resolution, distortion, and artifacts.

Image Detail

• Sharpness (Spatial Resolution): Amount of detail in a digital image, limited by pixel size.
• Visibility (Contrast Resolution): Ability to display changes in grayscale values, enhanced by postprocessing.

Image Distortion

• Misrepresentation of object size/shape.

• Reduced by positioning the part parallel to the IR and perpendicular to the CR.

• Elongation: Object appears larger/longer than normal.

• Foreshortening: Object appears smaller/shorter than normal due to poor alignment.

Image Artifacts

• Undesirable objects/structures degrading image quality.
• Types: Image receptor, software, and object artifacts.