Final 1 Flashcards
List 10 indicators for when to order diagnostic imaging.
- Trauma
- Unexplained weight loss
- Hx of malignancy
- Night pains
- Inflammation or arthritis
- Nero-motor problem
- Fever of unknown origin (FUO)
- Failure to respond to therapy
- Deformity
- Abnormal blood findings
- Medico-legal implications (must take imaging before surgery)
What is conventional tomography?
Is it used much?
NOT a CT;
It is a type of tomography that moving X-rays images around the body allows for focal clarity.
Not widely used
What is the difference in appearance between a plain x-ray and conventional tomography?
Plain X-ray does not show bone destruction on a small scale.
Conventional tomography can be seen in axial slices from the moving camera and film.
Which imaging plane is commonly used in computed tomography (CT)? Can more than one imaging plane be demonstrated with CT?
Axial
Yes; however the resolution is then decreased
What is the difference between CT soft tissue and bone window?
Soft Window better visualization of soft tissues.
Bone Window better visualization of the fine details of the osseous structures.
What is the appearance of bone in a soft tissue window?
Bone appears white or light grey
What is the appearance of bone in a bone window?
cortex being light/white and the medullary being semitransparent.
Does CT utilize the theory of attenuation (absorption of x-rays)?
Yes
Which is more sensitive in the differentiation of tissue densities, CT or plain X-ray?
CT, because it can image the soft tissues contrast.
What is the appearance of fat on CT vs. MRI?
CT fat is black, similar to air
MRI T1-> fat is white
MRI T-2-> fat is dark/grey
By what routes can CT contrast material be administered?
- Orally-> GI contrast (Barium)
- IV-> organs outside GI
- Rectally-> GI
- Myelographically in subarachnoid space-> spinal cord & brain (CNS)
- Intra-articular->Joint space
How does MRI acquire images?
hydrogen ions;
This released energy is what captures the image or difference in densities that portray an image that we see.
What does a T1 weighted MRI image look like compared to a T2 weighted image? What structures are high signal (white) vs. low signal (dark) on each weighting?
T1=> fat appears white bc=>fat sensitive weighted imaging.
*CNS fluid appears darker.
T2=> fluid appears light/white bc this is a water weighted imaging.
*Fat will appear darker/grey
Which modality would best demonstrate dehydration (desiccation) of the nucleus pulposis, CT or MRI?
MRI T2 imaging because it is a water weighted imaging.
If dehydration=> lack of water would appear dark.
Which modality would best demonstrate an intervertebral disc herniation, CT or MRI?
(MRI) T2 imaging, bc gelatinous fluid in disc is 80% water.
What is the contrast called that is sometimes used with MRI and why is it used?
Gadolinium=> Infections, tumors soft tissues and vasculature
Where is the contrast material placed in myelography?
subarachnoid space
What modality besides plain film radiography is myelography often used with?
CT=> b4 a surgery
When is myelography utilized?
Pre-surgery or when an MRI or CT is not available or contraindicated.
Also in examining lesions, disc herniation, tumors, osteophytes and inflammation.
What is a “hot spot” in bone scan?
Bone destruction, bright white spot or hot spot on the bone scan.
When might SPECT scan be useful?
For localizing a lesion and/or confirming a fracture in the pars interarticularis.
When might PET scan be useful?
Accessing treatment success or tumor localization,
When might discography be useful?
To document a specific disc lesion or pain and to access disc integrity
When might diagnostic ultrasound be useful?
- Thyroid gland
- Heart
- Gallbladder/gallstones
- Kidney/kidney stones
- Pregnancies/fetus
- Observe scrotum and prostate
- Evaluate blood flow
- Help Dx CA or infection
- Guide needles for aspirating tumor biopsy or for treatment
