Imaging and Clinical Applications Flashcards by Sarah L

Q

4 things that should be done for all patients’ studies

A

Verify patient identity (patient name matches on study)
Verify date/time of study is correct
Verify study type i.e. x-ray/CT/MRI is correct
Get older study or record for comparison

Steps 1-3 = ALWAYS DO, Step 4 = Optional but ideal

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Q

What are the 4 types of radiological studies?

A

Plain x-rays
CT scans
MRI
Ultrasound

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Q

What is an orthogonal x-ray?

A

X-ray taken at 90 degrees

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Q

Commonly ordered X-ray views for:

Chest (3)

A

PA or AP
Lateral
Portable

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Q

Commonly ordered X-ray views for:

UE (3)

A

AP (frontal)
Lateral
Oblique (let’s you see things between AP & lateral)

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Q

Commonly ordered X-ray views for:

LE (3)

A

AP (frontal)
Lateral
Oblique (let’s you see things between AP & lateral)

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Q

Commonly ordered X-ray views for:

Abdomen (4)

A

Supine
Upright
Decubitus
AAS

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Q

Commonly ordered X-ray views for:

Pelvis (3)

A

AP (inlet/outlet)
Lateral
Frog-leg

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Q

Commonly ordered X-ray views for:

Facial B./Skull (4)

A

Frontal
Lateral
Upright Water’s
Nasal Views

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Q

Commonly ordered X-ray views for:

Cervical spine (5)

A

AP
Lateral
Oblique
Flexion/Extension
Open-mouth

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Q

Commonly ordered X-ray views for:

Thoracic spine (3)

A

AP
Lateral
Oblique

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Q

Commonly ordered X-ray views for:

Lumbar spine (3)

A

AP
Lateral
Oblique

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Q

Commonly ordered X-ray views for:

Sacral spine (1)

A

AP (inlet/outlet) same as pelvis
- Caveat: low sensitivity

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Q

Ideal imaging modality for sacral spine

A

CT

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Q

Ideal imaging modality for neurologic injuries

A

MRI

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Q

Order the following from least dense to most dense:

Soft-tissue
Bone
Air
Metal
Fat

A

Air
Fat
Soft-tissue
Bone
Metal

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Q

Match structure to expected appearance on plain films:

Air, fat, soft-tissue, bone, metal

Very bright (very white)
Dark (black, radioluscent)
Bright (white)
Less dark, but still dark
Medium (gray)

A

Air = dark
Fat = less dark, but still dark
Soft-tissue = medium (gray)
Bone = bright
Metal = very bright

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Q

Distinguish between a PA and AP view

where is beam traveling from?
where is film that beam is traveling to and hitting?

A

PA view
- beam traveling from back (P) and hitting film in front (A)
AP view
- beam traveling from front (A) and hitting film back (P)

Q

PA or AP view, which is preferred in majority of chest cases?

Why?

Under what circumstances is the other usually ordered?

A

PA view
AP view can give enlarged view of heart & vessels leading to false cardiomegaly dx
AP view usually ordered when unable to position patient erect as needed for PA

Q

Fractures are easily identified on plain films by looking for ______ (outer portion of B.) disruptions

A

Cortical disruptions

Q

Fluid is ______ dense than air and therefore appears _____

A

more dense than air and therefore appears medium gray to bright white

Q

Calcifiied structures that appear dense and bright on abdominal x-rays?

A

kidney stones

Q

4 patterns of plain film misdiagnosis?

Nml ____ & _____
_____ recognition failure
Associated _____
Suboptimal _____ & number of ______

A

Nml anatomy & variants
Pattern recognition failure
Associated pathology
Suboptimal positioning & number of projections (only visible on certain view, all other views nml)

Q

Presence of what structure visualized on an x-ray can indicate the patient is a child?
What does it look like?

A

Growth plate
Smooth, radioluscent line

2 imaging modalities that present with ionizing radiation risk

* X-rays * CT scans

Order the following from least hounsfield unit (HU, aka x-ray beam) absorbed to most HU absorbed on CT. * H2O * body fluid, i.e. ascites * blood * fat * air * bone/metal

1. air (least dense, -800 HU) 2. fat (-70 HU) 3. H2O (0 HU) 4. body fluid, i.e. ascites (0-20 HU) 5. blood (40-60 HU) 6. bone/metal (800+ HU)

On CT dense structures appear? less dense structures appear?

* Dense structures appear white * Less dense structures appear darker

Different _____ in CT enables evaluation of different organs within single image.

windowing

Almost all CT scans are acquired in what plane?

axial plane

how are 3D or coronal, sagittal, and oblique plane images acquired in CT scans?

through reformatting and stacking of axial scan images

3 things useful for clinicians to know when evaluating CT images?

* slice thickness * location of 1st and last slices * type of contrast used

How is CT angiography similar to conventional angiography? How is it different?

Similar: obtain same info, radiation exposure, IV contrast use Different: less invasive

How is CT angiography different from basic CT?

* need faster scanner * need larger needle size to get faster IV contrast injection rate

How does water appear on T2 MRI images?

*Remember WWII:* **_W_**ater appears ****_W_**hite** on _T2 (II)_ images

How does water appear on T1 MRI images?

Black (opposite of T2)

How do tumors and inflammatory masses appear on T2 images?

white

Advantages of MRI: * Greater ____ of soft tissue * Acquired \_\_\_\_\_ * Get vascular study \_\_\_\_\_ * No \_\_\_\_\_

* Greater **differentiation** of soft tissue * Acquired in **any plane** * Get vascular study **without IV contrast** * No **radiation exposure**

Disadvantages of MRI: * Longer \_\_\_\_\_\_ * Very sensitive \_\_\_\_\_\_

* longer **aquisition time** * very sensitive **motion artifact**

Advantages of U/S: * No \_\_\_\_ * Acquired \_\_\_\_\_ * Less \_\_\_\_ * Performed at \_\_\_\_\_ * Provide ____ imaging

* No **radiation exposure** * Acquired in **any plane** * Less **expensive** * Performed at **bedside** * Provide **real-time** imaging

Disadvantages of U/S: * Less _____ images * Takes _____ than CT * ______ depending on operator skills * ______ are 2 structures not visualized well in U/S

* Less **sharp & clear** images * Takes **more time** than CT * **Highly variable quality and accuracy** depending on operator skills * **Bones and lungs** are 2 structures not visualized well

What is the concern w/ CT imaging in pregnant women?

Ionizing radiation exposure to fetus

What is the concern w/ MRI in pregnant women?

Field strength (1.5T vs 3T) can potentially heat fetal/amniotic fluid

What are 3 contrast agents that should be avoided when imaging pregnant women?

* iodinated contrast * oral contrast * gadolinium