1. Intro to Medical Imaging_Krayssa_Student

Is an underexposed X ray too dark or too bright? Overexposed?

underexposed is too bright overexposed is too dark

What is the benefit of using an MRI over a CT?

MRI imaging produces better soft tissue contrast than CT.

X-rays: Describe the plate location and the patient's body angle of a: Left anterior oblique projection

(Tip: refer to left/right by which shoulder is on the plate)

X-rays: Describe the plate location and the patient's body angle of a: Left posterior oblique projection

(Tip: refer to left/right by which shoulder is on the plate)

What are pros and cons of MRI vs. CT

MRI- better image, but user dependent and takes longer to obtain CT- quicker but contains radiation exposure

X-rays: Describe the plate location and the patient's body angle of a: Right anterior oblique projection

(Tip: refer to left/right by which shoulder is on the plate)

X-rays: Describe the plate location and the patient's body angle of a: Right posterior oblique projection

(Tip: refer to left/right by which shoulder is on the plate)

What is the most commonly used oral contrast media? (for X-rays and CT)

Barium

What are two types of oral contrast for X rays and CT?

Barium and gastrografin

Which three imaging techniques are considered Tomography?

- CT (Picture) - MRI - Ultrasonography (They make SLICES-blurs out features in front of and behind anatomical plane of clinical interest )

What are two common IV contrast media?

- Iodide-based -CT - Gadolinium-based -MRI

What is the radiation exposure (mSv) for a PA chest radiograph?

0.02 mSv

What is the range of radiation exposure (mSv) of nuclear imaginng?

0.1-11 MsV Depends on the procedure. Depending on pharmaceutical, NOT rays.

CT: What structures do black and white colors represent in a CT scan?

(Similar to X-ray images) White - Bone or contrast Light Grey - Organs Dark Grey - Muscle or Fluid Black - Gas (Know the extremes)

5 radiographic densities X rays (Label 1-5)

1. Black=gas 2. Grey= fat 3. Light grey=fluid 4. whitish= bone 5. white=metal

For almost every body part, the radiograph (AP, PA, or oblique) is viewed as if the patient is looking at you. What are the two exceptions?

1. Hands, wrists, and feet are viewed as if you are looking at your own. 2. Forearms can be viewed both ways.

What to consider when interpreting radiographs?

1. labels (view and R or L) 2. previous exams (acute vs. chronic, pre/post treatment) 3. quality of film 4. interpretation

4 things to consider in interpreting radiographs?

1. radiographic densities 2. radiographic edges (ie air fluid level) 3. Radiographic projections (position of PT) 4. resolution

What is the strength of an MRI magnet?

1.5 Telsa

What is the radiation exposure (mSv) for a CT of the head?

2 mSv

What is the radiation exposure (mSv) for a abdominal CT?

8 mSv

What are the different colors in nuclear imaging?

Black= target organ / structure (where the tracers had affinity for) Grey= other organs white= bone

Ultrasonography: If a structure is white, it is said to be: A. Hyperechoic B. Hypoechoic C. Anechoic

A. Hyperechoic White: Solids

What imaging technique can be used to visualize the inside (lumen) of blood vessels or heart?

ANGIOGRAPHY (can be used to produce angiograms and perform angioplasty/stent) CT: CT Angiogram (CTA) MRI: MR Angiogram (MRA)

A patient is standing with an X-ray source to the front and a X-ray detector on his back. Is this a PA or AP view?

AP view X-ray source: ANTERIOR (magnified view)

What is the advantage and disadvantage of nuclear imaging.

Advantage: Produces functional images Disadvantage: Poor spatial resolution (Image)

Ultrasonography: If a structure is grey, it is said to be: A. Hyperechoic B. Hypoechoic C. Anechoic

B. Hypoechoic Grey: Tissues

X-ray: True or False. PA and AP are switched in what views? A. Lateral B. Oblique

B. Oblique

What are three names of nuclear imaging scans?

Bleeding Scan (image) HIDA Scan Bone Scan (radiotracer attaches to WBCs which light up with gamma camera) others: PET (tumors), SPECT, SBC-tagged scan(aka Indium scan)

Ultrasonography: If a structure is black, it is said to be: A. Hyperechoic B. Hypoechoic C. Anechoic

C. Anechoic Black: Fluids

When would you use a CT over an MRI?

CT- acute issues with soft tissue (appendicitis, spleen rupture, brain hemorrhage) MRI- tumors or orthopedic injuries (joints)

What are two types of IV contrast for CT and MRI?

CT= iodide based MRI= gadolinium based

X-ray: If you have ________________ on your lateral plate, the plate will be on the ________________ of the patient. A. left sided label, right B. left sided label, left C. right sided label, left D. right sided label, right E. A and C F. B and D

E. A and C The label describes the patients side that is CLOSEST to the x-ray detector.

MRI: Describe the difference between T1 and T2 weighted images.

Fluid color is different. T1- Weighted: Fluid is dark T2- Weighted: Fluid is bright (Image: CSF is white on the T2- weighted image)

How does nuclear imaging work?

Gamma camera is used to detect an injected radionuclide in the patients. -timing very important, must obtain images at very specific times depending on what you want to see

How would you differentiate a CT scan from an MRI scan?

If a T2-weighted image was produced using an MRI, Fluids in the image would appear bright. In a CT scan, fluids would appear dark grey.

CT: Describe how a lung would look using a lung window setting?

Lung markings; pulmonary veins are visible. (can also use soft tissue and bone settings)

A patient is standing with an X-ray source in the back and a X-ray detector on the front. Is this a PA or AP view?

PA view X-ray source: POSTERIOR (more accurate size)

The fundamental imaging technique in nuclear medicine is called ________________

Scintigraphy

What are the three types of resolution?

Spatial Resolution: High spatial resolution = Sharp image. Can be seen as 'Sharpness'. Contrast Resolution: allows differentiation among types of tissues.(can be increased by giving patient contrast) Temporal Resolution: the ability to image a structure in a narrow window of time. (shows function)

What is angiography used for?

To visualize arteries, veins, and heart chamber. CT or MRI can be used to produce an angiogram.

True of False? CT and MRI have better spatial resolution than X-rays

True (MRI better contrast resolution than CT in soft tissues)

True or False. MRI does not give radiation exposure

True (but must be screened for any metal in body)

Most of the radiation from X-ray and CT scans are inflicted by contrast media. True or False

True. The X-ray source itself gives off very little radiation.

A transducer produces sound waves which are reflected (echoed) back, producing an image. What imaging technique is this?

Ultrasonography

Which imaging technique is used to produce a Radiograph?

X-ray

Define Radio-lucent and name the imagining technique related to it

X-ray Blacker = Radiolucent (less radiodense)

Define Radio-opaque and name the imagining technique related to it

X-ray Whiter = Radiopaque (photons get absorbed so more radioDENSE)

A radiation dose is expressed in ______________.

millisieverts (mSv)

When ordering oblique view, you want the ________ to be closest to what you want to see. (plate or x-ray detector?)

plate

whos at risk for having an adverse/allergic response to IV contrast

renal disease (contrast induced nephropathy) diabetics asthma or allergies dehydration sickle cell anemia certain meds (NSAIDS, beta blockers) having a large amount of contrast in 24 hours

is radiation exposure higher with contrast?

yes