Soft Tissue Imaging Notes Week 1

Introduction to Soft Tissue Imaging

  • Course Overview

    • 2 hours of class per week.

    • Combination of lecture and lab style.

    • Assessment involves graded in-class tasks/quizzes (15%) and midterm/final exams (85%).

Course Description

  • Focus on radiographic and advanced imaging techniques for the thorax, abdomen, pelvis, and head/neck.

  • Study various imaging modalities and contrast agents.

  • Emphasizes reinforcement of normal anatomy and imaging appearances of common conditions/diagnoses.

  • Discussion on appropriate follow-ups including referrals and additional imaging.

Common Imaging Modalities

  • With Radiation:

    • Radiography

    • CT/CBCT

    • Nuclear Imaging (e.g., PET)

  • Without Radiation:

    • MRI

    • Ultrasound

    • DEXA

Imaging the Thorax and Abdomen

Radiography

  • Initial imaging technique offering limited assessment.

  • Can utilize contrast agents for gastrointestinal evaluations (e.g., barium for GI tract).

Ultrasound

  • Not often used for chest imaging; primarily used in neck and abdominal investigations.

  • Operator-dependent quality; ideal for superficial soft tissue evaluations.

    • Pros: Cost-effective, no ionizing radiation.

    • Cons: Field of view limitations, very dependent on operator skill.

    • Indications: Useful for assessing soft tissue masses, fluid collections, and certain vascular conditions.

    • Limitations: May not provide adequate detail for deeper structures or pathologies.

  • Ex: Thyroid Imaging: Used for evaluating nodules, e.g., detecting deviated trachea.

  • Ex: Musculoskeletal Use: Assessing hematomas or tears, e.g., biceps mm. tear with hematoma.

Multi-planar Imaging Techniques (CT & MRI)

  • Imaging in various planes:

    • Sagittal

    • Axial

    • Coronal

    • Oblique

MRI vs. CT Imaging

MRI:

  • Generally takes 45 minutes to 1 hour.

  • Best for soft tissue evaluations, including tendon/ligament injuries and brain monitoring.

  • Pros: High soft tissue contrast.

  • Cons: Longer duration, potential for motion artifacts in dynamic anatomy areas.

CT:

  • Takes about 10 minutes; great for acute scenarios.

  • Best for rapid evaluations of chest and abdomen, often requires GI &/or IV contrast.

  • Pros: Quick scan time, excellent bone detail.

  • Cons: Ionizing radiation exposure, lesser soft tissue contrast compared to MRI.

Contrast Administration

  • Types of Contrast Agents:

    • Intravenous (IV): Gadolinium for MRI; iodine-based for CT.

    • Gastrointestinal (GI): Barium sulfate used for oral/enema.

    • Arthrograms: Intra-articular contrast administration to help in joint assessments.

Chest Imaging Techniques

Chest Radiographs

  • Key Considerations:

    • Requires full inspiratory effort, proper patient positioning, and specific technical settings (high kVp, low mAs).

  • Standard Projections: PA (Posteroanterior) and lateral views are essential for normal chest evaluations.

Search Patterns in Chest Radiography

  • Assess structures systematically:

    • Trachea

    • Mediastinum

    • Hilum

    • Heart

    • Diaphragm

  • Look out for abnormalities in the anatomy and detect pathologies through density, contour, and positioning assessments.

Chest Projections

Standard: PA and Lateral (upright vs recumbent)

Accessory: Apical lordotic, lateral decubitus, PA expiration

  • Normal Anatomy Visible:

  • Trachea

    Mediastinum

    Hilum

    Heart

    Diaphragm

    Cardio/costophrenic angles

    Lung zones

    Retro sternal/cardiac spaces

    Bony structures

    Subdiaphragm soft tissues

    Extrathoracic soft tissues