Intro to Radiology Flashcards
1
Q
Who discovered radiology
A
- 1895 William Roentgen
- Experimenting with electricity passing thru glass vacuum tube
- Invisible energy caused florescence and passed through objects
2
Q
Imaging Modalities
A
- X-ray (plain films)
- Computed Tomography (CT)
- Magnetic Resonance Imaging (MRI)
- Ultrasound (ULS)
- Nuclear Medicine
- Fluoroscopy (joints, angiography, swallow studies)
3
Q
Terminology: Plain X-Rays
A
- Radiolucent
- Radiopaque
4
Q
Terminology: CT
A
- Low attenuation
- High attenuation
5
Q
Terminology: Nuclear
A
- Low uptake
- High uptake
6
Q
Terminology: MRI
A
- High signal
- Low signal
7
Q
Terminology: Ultrasound
A
Anechoic, hyperechoic, hypoechoic, acoustic shadow
8
Q
PACS - modern radiology
A
-picture archiving and communication system
- Computerized replaces hardcopy
- Instant access, old films archived
- Teleradiology
- Images to CD for patient/referral
- Hardcopies
- Rural/remote and international
- Back-up when electricity fails
- View box: old->new viewed left to right
- Orientation: pt’s right on your left*
9
Q
Plain x-rays are good for:
A
- Bone
- Lung and pleura pathology
- Foreign bodies
- Air filled structures (lung, bowel)
10
Q
Plain x-rays are not good for:
A
- Detail, precise location
- Solid organs
- Brain
- Vasculature detail
11
Q
Indications for CXR
A
– Respiratory symptoms
– Chest pain
– Fever
– Upper GI complaints
– Procedures/lines
– Trauma
– Admission
12
Q
Indications for Face/Spine X-ray
A
-PLAIN X-RAY IS NOT THE INITIAL TEST IN THIS CASE
– Fractures/trauma
– Soft tissues: neck
13
Q
Indications for abdomen X-ray
A
-PLAIN X-RAY IS NOT THE INITIAL TEST IN THIS CASE
– Obstruction
– Foreign Bodies
14
Q
Indications for extremities X-ray
A
– Fracture/trauma
– Foreign bodies
– Gas, fluid in soft tissue
– Metabolic Dx
– Bony tumors
15
Q
Density on plain x-rays
A
- Dense, thick - radiopaque = white – Absorbs more xray
- Less dense, thin - radiolucent = grey to black – absorbs less xray
- Shades of grey essential to identify structures, position, overlap
- Rads techs can adjust for pt size – Can change wavelength for density – Can change milliamps and time of exposure
- Easy to change w/ PACS
16
Q
How are air-fluid levels seen
A
-ONLY IF X-RAY BEAM IS HORIZONTAL TO THE FLOOR
17
Q
When do objects appear larger on x-ray
A
- If beam source is closer to the patient/object
- If object is further from imaging surface
18
Q
How to determine if the x-ray is taken in the lordotic position
A
-CLAVICLES they should be between the 3rd and 4th rib, but they will be riding high
19
Q
Computed Tomography (CT)
A
- 1972: Godfrey Hounsfield
- Initially took 9 hours to produce image
- 1976: whole body scanners “tomos” and “graphein” Prototype t=4 min (each “slice”)
- 2006 t=0.5 sec • 2014 t=0.3 sec: multirow detector, less radiation
20
Q
Orientation of patient - CT
A
looking at a CT, the pts right is on your left, and the left is on your right. The anterior is top and posterior is bottom
21
Q
Density in CT scans
A
- Referred to as attenuation
- High attenuation = dense – White on image
- Low attenuation = less dense – Shades of grey to black
- Qualified as Hounsfield units by radiologist
22
Q
CT contrast studies
A
- Adds density (it’s white), defines structures
- IV, PO: Barium
- Contras: renal insufficiency (creatinine >1.5), allergy
- Indications – IV: vasculature, tumors, abdominal pathology – Oral: bowel
- No Metformin 24hrs before/48hrs after contrast
23
Q
CT indications: head/brain
A
- Injuries/trauma, CVA, Altered Mental Status, New Sz, etc
24
Q
CT indications: chest
A
– Lung abnormalities
• infection, tumor, effusion, etc – Pulmonary embolus – Aortic issues
25
CT indications: abdomen
– Acute infections/inflammation – Obstruction (bowel, stone) – Cancer staging
26
CT indications: extremities/face/spine
– Complex fractures – Infection
27
CT advantages
* Readily available
* Great for bone detail
* Great for brain and abdomen
* Can be used with metallic FB
* 3-dimensional versus 2-D conventional xray – Can reformat images for clarity, precision
28
CT disadvantages
* Radiation dose
* Ischemic CVA – misses subtle, new ones
* Vertebrobasilar system (cerebellum) – not great here
* Renal function for contrast
* Replacing traditional medicine
29
MRI
* 1st proposed in 1976, in use by ‘84
* Applies a powerful magnetic field to atoms which realign and release energy
* Radio wave mapped as image
* High or low “signal”
* T1 or T2 weighted – basic
* Contrast = gadolinium
* Will likely replace CT in your career
30
MRI indications
* Ligament/Tendon injury (soft tissue)
* Spine/spinal cord injury or lesion (tumor, abscess)
* Brainstem/cerebellar pathology
* Intracranial masses, tumors – detail, staging
* CVA – non-con CT first, MRI follows CT
* Multiple Sclerosis, Encephalitis
* Ortho: occult fx’s (esp hip, scaphoid), avascular necrosis, tumors, osteomyelitis, stress fractures
* Biliary tract - MRCP – gallstone pancreatitis, cholangitis
* Pregnant pt
31
MRI advantages
* Non-ionizing radiation
* No known side effects
* Excellent for soft tissue
* Shows vasculature w/o contrast
* Definitive study for brain and spine
* Titanium, stainless steel OK
* Contrast = gadolinium = no renal damage unless GFR \<30ml/min
32
MRI disadvantages
* Cost
* Not readily available as CT
* Claustrophobia (10% failure)
* Imaging time, motion artifact
* Contraindications – Unstable patient – Ferrous metal – Pacemaker
33
MRI: T1 or T2 weighted
* “Weighting” is how the image is presented w/ respect to pulse sequence parameters that affect proton relaxation time
* T1 weighted – water is black (low signal), fat is bright (high signal)
* T2 weighted – water is bright, fat is black
* Contrast bright white on both
* Brain/spinal cord MRI --\> look at CSF
34
MRI in orthopedics
-Widely used
* Multiple soft tissue structures, bone, joint spaces, synovial fluid
* Can reformat with “fat suppression”
* Review with radiologist
35
Ultrasound
* Uses high frequency sound waves
* Echoes are produced
* Does not use ionizing radiation
* Unique nomenclature
* Has completely revolutionized Emergency Medicine
36
Ultrasound advantages
* Cheap, safe, portable, instant
* No radiation
* Real time guidance for procedures
* Color doppler use for vasculature
* Serial exams at bedside
* Peds – can avoid radiation
37
Ultrasound disadvantages
-operator dependent
38
Ultrasound indications
* Trauma: FAST Exam
* Cardiac (Echo)/Lung
* Obstetrics & Gynecology
* Aorta
* Biliary System, Kidneys, Bladder, Appendix
* IV’s/Central Lines
* DVT
* Abscess, Foreign Bodies
* Soft Tissue, Eye
* Nerve Blocks
* Lumbar Puncture
* Etc, Etc…
39
Nuclear Studies
* Patients given nuclear agent with short half life
* Agent has affinity for certain organs (thyroid, bone, lung, heart, tumor)
* Scanner picks up static tracer concentration or dynamic rate of tracer through blood flow
* High or low “uptake”
* Equipment and operation highly specific, interpreted by radiologist
* Difficult to obtain at odd hours
40
Nuclear Medicine Studies
* PET scan
* Bone scan
* Thyroid scintigrophy
* V/Q scan
* HIDA scan (gallbladder)
* Myocardial Perfusion Scan
* Cancer diagnosis/staging
* Dx and treatment of thyroid goiter, nodules, hyperthyroidism, cancer
* Pulmonary Embolus
* Choledocholithiasis
* Cardiac Perfusion Studies
41
PET scan
* Positron Emission Tomography
* Radioactive material IV
* Pt is briefly a “source” of radiation
* Scan detects positron uptake:
* “Lights up” – Cancer/tumors – Coronary heart disease – Seizure disorder – Alzheimerʼs
42
V/Q scan
* Dx of pulmonary embolus if CT w/ con not possible
* Assessment of regional lung function
* V= ventilation
* P=perfusion
* Alternative to CT, less sensitive, used less
43
Fluoroscopy
* Live images in motion with continuous x-ray
* Can follow fluid thru hollow spaces to check integrity
* Used to monitor path of needles, injections or capture items/structures
* Real-time guidance for procedures/surgery
44
Examples of Fluoroscopy
* Ortho joint injections, surgical guidance
* Cardiac angiography
* GI swallowing studies
* Cystourethrogram
* Special lumbar punctures
* Complex vascular access
* Removal foreign bodies
45
Angiography
* Study of blood vessels
* Heart, brain, etc
* Stenosis, aneurysms
* IV contrast
* Conventional fluoroscopy
* CT or MRI
