Exam I Flashcards
Abdominal (Convex or Curved Array) Probes
Used for general abdominal imaging, transabdominal pelvic imaging, obstetrical imaging, and some musculoskeletal imaging
Wide-angle field of view for large deeper structures (e.g., kidneys)
Cardiac (Sector Array) Probes
Produce a triangular sector image
Suited for imaging large, non-superficial structures through narrow sonographic windows (e.g., heart)
Not ideal for imaging superficial structures
Linear (Linear Array) Probes
Offer the best image detail but limited depth penetration (5-6 cm maximum from skin surface)
Used for musculoskeletal, peripheral nerves, thyroid gland, breast, and superficial vascular imaging
Produce rectangular-shaped images with constant width from probe face to deepest part
Echogenicity
Reflectivity of tissue in relation to surroundings
Visible contrast in brightness at tissue interfaces
Hyperechoic
White, high reflectivity
Hypoechoic
gray, moderate reflectivity
Anechoic
black, little to no reflectivity
Transducer scanning positions: Transverse
axial (right to left) orientation of the ultrasound probe with the transducer indicator notch towards the patient’s right such that the left side of the sonogram should display structures on the patient’s right side
Transducer scanning positions: Longitudinal (also called Sagittal)
cranial to caudal orientation of the ultrasound probe with the transducer indicator notch towards the patient’s head such that the left side of the sonogram should display structures nearer to the patient’s head
Transducer scanning positions: Radial
used in breast US and follows a wagon wheel pattern of scanning with the nipple in the center to visualize the breast plane parallel to the ductal system
Transducer scanning positions: Antiradial
used in breast US and is a scanning plane 90 degrees to the radial scanning pattern and is used to visualize the breast plane perpendicular to the ductal system
Attenuation
the degree to which x-rays are absorbed/deflected by the body part
Flesh
lower atomic weight (transparent)
Bones
higher atomic weight (attenuate)
Radiodensity
the amount of black on the image, The more dense a tissue is, the LESS blackening and the MORE white the image
Radiolucent
Easily penetrated by X ray beams
Example: air= black
Radiopaque
Not easily penetrated by X ray beams
Example: metal=white
CT contrast
Fluoroscopy
X-Ray examination in real time, continuous x-ray beam. Commonly used in fracture fixation, arthrography, myelography, diskography, biopsy, gastrointestinal evaluation
CT Scan indications
Trauma, subarachnoid hemorrhage, acute cervical spine injury, acute appendicitis, ureteric calculus
CT scan contraindications
Pregnancy, young age, claustrophobia, allergy to contrast medium, weight/girth
Computed Tomography (CT) Scan
Excellent demo of cortical bone anatomy, but poorer soft tissue demonstration
Fast, easy to perform, readily available
shows blood and acute bleeding very well, will show up bright white on CT scan.
usually first imaging choice for trauma patients
Magnetic Resonance Imaging (MR or MRI)
non-ionizing,
MRI is based on measurements of energy emitted from hydrogen nuclei following their stimulation by radiofrequency signals.
The energy emitted varies according to the tissues from which the signals emanate.
This allows MRI to distinguish between different tissues
T1 Weighted Image
Best for anatomical localization (measures energies rapidly and early)
Balanced images, picks up adipose tissue and bone marrow well, but not CSF
High water content areas appear dark in T1 images
T2 Weighted Image
Best for contrasting normal and abnormal tissue (measures energies slowly and late)
High water content areas appear bright in T2 images
-fluid, edema, CSF in spaces, cysts, abscess, tumors, acute hemorrhage
T2 – H20 = Bright white = fat AND water)
Excellent at detecting inflammation