pt 3 Ultrasound Imaging: Evaluating Abnormalities and Anatomic Directions

Identifying Abnormalities

• Pathology Evaluation:

  • Important for sonographers to identify abnormal structures.

  • Techniques include evaluating normal anatomy and potential pathologies surrounding it.

• Criteria for Identification:

  • Abnormalities assessed based on:

  • Border Definition: Smooth vs. irregular borders.

  • Internal Texture: Determined by echogenicity (anechoic, hypoechoic, isoechoic, hyperechoic).

  • Tissue Characteristics: How the tissue reflects sound.

  • Sound Transmission: Increased, decreased, or unchanged sound transmission through the mass.

• Types of Masses:

  • Cystic Mass:

  • Well-defined smooth border; anechoic; increased transmission behind.

  • Solid Mass:

  • Irregular borders; internal echoes (echogenic); decreased transmission.

  • Complex Mass:

  • Combines both cystic and solid characteristics.

Anatomic Directions

• Body Orientation:

  • Anatomic Position: Standing erect, eyes forward, arms at sides, palms/toes forward.

• Directional Terms:

  1. Superior/Inferior:

  • Superior: closer to the head (e.g., liver > bladder).

  • Inferior: closer to the feet (e.g., gallbladder < diaphragm).

  1. Anterior/Posterior:

  • Anterior: belly surface (e.g., aorta > vertebral column).

  • Posterior: back surface (e.g., right kidney < head of pancreas).

  1. Medial/Lateral:

  • Medial: closer to midline (e.g., hepatic artery > common duct).

  • Lateral: towards the side (e.g., adnexae > uterus).

  1. Proximal/Distal:

  • Proximal: closer to midline (e.g., hepatic duct > common bile duct).

  • Distal: farther from midline (e.g., sphincter of Oddi < common bile duct).

  1. Superficial/Deep:

  • Superficial: close to the body surface (e.g., rectus abdominis > transverse abdominis).

  • Deep: farther inward from surface.

Criteria for an Adequate Scan

• Optimal Imaging:

  • Aim for maximal anatomical landmarks in one image.

  • Avoid rib interference to reduce artifactual noise (e.g., ring-down, attenuation).

• Transducer Types:

  • Curved array multi-hertz transducer is often used for abdominal surveys.

  • Small-footprint sector array allows scanning between ribs but limits near-field visualization.

• Scanning Techniques:

  • Observe breathing impact on imaging, adjust patient’s position as necessary.

  • Ensure the controlled environment for optimal patient comfort and image clarity.

General Abdominal Ultrasound Protocols

• Sonographer's Responsibilities:

  • Ensure high-quality care: patient identification, confidentiality, and cleanliness of equipment.

• Abdominal Examination:

  • Use high-resolution real-time ultrasound equipment for imaging.

  • Varying transducer frequency (2.25 to 7.5 MHz) depending on patient size and depth of field.

• Imaging Techniques:

  • Scan organs in two planes: transverse and longitudinal.

  • Sweep motion used initially to survey the abdomen, marking major structure locations.

  • Focus on specific organs based on prior assessments, adjusting the transducer appropriately to visualize anatomy.

• Typical Scanning Sequence:

  • Start at the xiphoid level, moving systematically through the abdominal structures (e.g., liver, gallbladder, kidneys).

  • Maintain communication with the patient during the process for breathing adjustments to aid imaging.