Introduction to Radiology

Radiology

Use of medical imaging to diagnose and treat illness and injury

Distortions of Anatomy

Changes in structure

Changes in Physiology

Changes in function

Nuclear Medicine

Imaging modality using radioactive substances

X-rays

Imaging modality using electromagnetic radiation

CT (Computer-Assisted Tomography)

Imaging modality using x-rays and computer processing

Ultrasound

Imaging modality using high-frequency sound waves

MRI (Magnetic Resonance Imaging)

Imaging modality using magnetic fields and radio waves

X-ray Technique

X-ray beam directed towards patient, creating an image based on absorption and penetration

Plain Film X-Ray

X-ray that creates a 2-D representation of 3-D structures

Basic Radiographic Densities

Different densities of structures in an X-ray image

Radiolucency

Appearance of black on X-ray due to air or low-density structures

Radioopacity

Appearance of white on X-ray due to dense structures

Radiodensity

Degree of absorption of X-rays by a structure

CT (Computer-Assisted Tomography)

Uses x-rays and computer processing to generate cross-sectional views of anatomy

Computed Tomography (CT)

X-rays pass through the patient and are detected on the opposite side

CT Window

Specific computer display settings that manipulate image data to increase resolution of particular tissue

Hounsfield Units

Numerical scale standardizing radiodensity on CT

Ultrasound (Sonography)

Uses high-frequency sound waves to image structures within the body

Gray Scale

Ultrasound image displayed using shades of grey

Color Doppler

Ultrasound technique to visualize blood flow

Isoechoic

Having the same echogenicity as a reference structure

Anechoic

Appearing black on ultrasound due to lack of echoes

Hypoechoic

Appearing darker than the surrounding tissue on ultrasound