Midterm Review Slides Flashcards
(149 cards)
1
Q
What are the 3 anatomical planes?
A
- coronal/frontal (front and back)
- axial/transverse/horizontal (top and bottom)
- sagittal/longitudinal (left and right) – median (midline) or parasagittal (more left or right)
2
Q
CT/MRI Axial View in Images – Positions
A
- left: right side of patient’s body
- right: left side of patient’s body
- top: anterior side of patient’s body
- bottom: posterior side of patient’s body
3
Q
How does CT work?
A
- 3D representation
- cross-sectional image info based on tissue density, atomic weight of the molecules
- uses ionizing radiation from a source to produce an image
- source (emits radiation) and detector (picks up signal) rotate 360º around the patient as patient is moved through the scanner
- x-rays from different angles are processed by computers to create tomographic images
4
Q
CT
What are the 5 major tissue densities found on radiographs, from low to high density?
A
air (black) < fat (dark grey) < water/soft tissue/fluid (light grey) < bone (nearly white) < metal (white)
5
Q
CT
Describe the radiographic density of air.
A
low density
- air does not attenuate (block/scatter) the signal very well – ionizing radiation passes through the patient and hits the detector
- appears black
6
Q
CT
Describe the radiographic density of metal.
A
high density
- metal attenuates (blocks/scatters) most or all of the signal
- appears white
7
Q
CT
How does tissue density affect how it appears on radiographs?
A
- more dense substance → more signal attenuation (blocking) → substance appears more white
- thick structures attenuate more radiation than thin structures of the same composition
8
Q
CT
What appears as white on radiographs?
A
bone, blood, bullets (BBB)
9
Q
How does MRI work?
A
- 3D information
- provides images in any plane
- protons in a strong magnetic field are bombarded with low energy (non-ionizing) radiowaves
- powerful magnetic field aligns protons in the body
- when the field is turned off, protons relax and emit electromagnetic signals that are detected by the scanner (with specific amplitude and frequency), and these signals can be reconstructed in digital images of the human body
10
Q
What are the main uses of ultrasound imaging? (3)
A
- first-line in HEART IMAGING
- evaluation of ABDOMINAL and PELVIC ORGANS – fluid-containing things and stones (bile ducts, gall bladder, renal/ovarian/breast cysts, hydroneophrosis (enlarged kidney), evaluation of stones (gall stones, renal calculi))
- determination of CYSTIC (fluid-filled) vs. SOLID STRUCTURES
11
Q
How can you determine if a structure is cystic (fluid-filled) or solid in ultrasound imaging?
A
cysts do not reflect sound and are anechoic – appear black
12
Q
What is nuclear medicine?
A
branch of radiology that uses intravenous radio-pharmaceuticals for imaging
- radio-pharmaceuticals may be deposited in certain tissues, and emit gamma rays
- rays are detected by gamma cameras
13
Q
How does positron emission tomography (PET) work?
A
uses radioisotope fluorine-18 (positron emitter) to produce photons that can be imaged
- fluorine-18 can be incorporated into biologically active molecules (ie. fluoro-18-deoxyglucose used for cancer staging)
- ie. fluorine-18 labeled with glucose-like molecule – parts of the body that use glucose faster (like fast-growing cancers) preferentially take the radioisotope up
14
Q
Breast Cancer
What is the screening recommendation?
A
every 2-3 years for every woman aged 50-74
15
Q
Breast Cancer
What modality is used for screening?
A
mammogram (x-ray)
16
Q
Breast Cancer
Describe the epidemiology (Canada).
A
- 2nd most common cause of cancer death in women – accounts for 15% of all cancer deaths
- accounts for 25% of all new cancer cases in women
- around 1 in 8 women will develop breast cancer in their lifetime
- can occur in males – but less common
- 5-year net survival rate is high (89%)
17
Q
Breast Cancer
What is the sensitivity of the screening?
A
variable based on age
- detects ~73% of cancers in early 40s
- detects ~85% of cancers in early 60s
18
Q
Lung Cancer
What is the screening recommendation?
A
annual screening up to 3 consecutive times for:
- high risk adults 55-74 years old + ≥ 30 pack-years of smoking, and currently smokes or quit within the last 15 years
- ≥ 50 years old + ≥ 20 pack-years of smoking with other risk factors
19
Q
Lung Cancer
What modality is used for screening?
A
low dose CT (LDCT)
20
Q
Lung Cancer
Describe the epidemiology.
A
- accounts for 13% of all new cancer cases
- 5-year net survival rate is low (22%)
21
Q
Colon Cancer
What is the screening recommendation?
A
one of the following:
- every 1 year via fecal testing
- every 10 years via colonoscopy
- every 5 years via colonography
22
Q
Colon Cancer
Describe the epidemiology.
A
- accounts for 10% of all new cancer cases
- 5-year net survival rate is about average (67%)
23
Q
Colon Cancer
What is the sensitivity of the screening?
A
variable between ~86% (colonoscopy) to 96% (feces)
24
Q
Heart Screening
What is a heart attack?
A
occurs when part of the heart muscle does not get enough blood
- most are caused by CAD (blockage of the arteries that provide blood supply to the heart)
25
Heart Screening
What imaging modality is used? What does it detect?
CT scan of the heart
- detects calcium deposits in heart arteries (appear as bright white areas) – build-up of calcium and fat can result in narrowing and eventually blockage of these arteries, leading to symptoms of CAD
26
Heart Screening
What is coronary artery calcium score (CACS)?
CT scan of the heart gives a score based on the total area of the calcium deposits and density of the calcium present
27
Heart Screening
A CT scan of the heart is typically performed on what population?
people who are at risk of developing CAD – ie. individuals with a family history of heart attacks
28
How does imaging play a role in cancer treatment? Which modality is used?
- in a newly diagnosed cancer, one crucial aspect is determining whether the cancer has spread to other parts of the body
- PET allows doctors to visualize 'hot spots' which can represent cancer cells
29
Describe how x-rays and CT scans work similarly.
- generate x-ray photons using current applied to a metal (tungsten)
- photons are directed and interact with tissues, and are received by a detector opposite the patient
30
What does the frontal lobe control?
- motor control (precentral gyrus)
- eye movements (lateral cortex)
- language production (Broca’s area)
- executive function (prefrontal cortex)
- reasoning and rationale
31
What does the parietal lobe control?
- sensory interpretation (postcentral gyrus)
- visuo-spatial processing (attribution)
- language interpretation
- attention
32
How do we demarcate the frontal and parietal lobes of the brain?
separated by the central sulcus
- sulcus: cleft/invagination/fold
- gyrus: ridge/elevation
33
Describe the motor control pathway.
precentral gyrus (grey matter) → internal capsule (white matter) → midbrain (cerebral peduncles) → spinal cord (‘cortico-spinal tracts’)
- top-down control – with the exception of reflex arcs
34
What is fine motor control? Where does it require input from?
nuanced motions, balance, eye reflexes, etc.
- cerebellum: balance, voluntary moves, posture
- semicircular canals (temporal bone): balance
- caudate and lentiform nuclei: tuned movements
35
Describe the sensation pathway.
spine → midbrain → thalamus → parietal lobe (postcentral gyrus)
- bottom-up control
- differences in control between touch, pressure, temperature, and proprioception/vibrations
36
What is the spinal cord?
aggregation of nerves carrying sensory and motor functions
37
What are the segments of the spinal cord?
- cervical: C1-C7
- thoracic: T1-T12
- lumbar: L1-L5
- sacral: S1-S5
38
What is nuclear medicine/PET often used for?
usually used for scanning the whole body for hot spots
39
What are some image-guided interventions for uterine fibroids?
- uterine artery embolization via fluoroscopy (real-time x-ray)
40
What is the pre-central gyrus?
part of frontal lobe responsible for motor control (voluntary movement)
41
What is the post-central gyrus?
part of the parietal lobe responsible for sensory interpretation
42
What separates the pre-central gyrus and the post-central gyrus?
central sulcus
43
How do CT images compare to MRI images?
fuzzy, grainy, bright (especially outlines)
44
What is bile?
- mixture of water (> 97%) and salts, cholesterol, fatty acids
- produced by the liver
45
What are the functions of bile?
- surfactant – reduce surface tension in tracts and the digestive system
- emulsification – forms rounded 'micelles' around fat globules
result: along with pancreas enzymes (lipase), bile breaks down fatty acids and allows absorption by villi (small bowel)
46
What are the two radiographic views?
- posteroanterior (PA): x-ray beam enters from behind
- anteroposterior (AP): x-ray beam enters from front
47
Which radiographic view is less frequently used?
anteroposterior (AP)
48
Which radiographic view are radiographs in the supine (laying down) position done in?
normally anteroposterior (AP)
- indicated on radiograph with ↓
- magnifies cardiac/mediastinal shadow by 20-25%
49
What is the CT (cardiothoracic) ratio?
(maximum transverse diameter of heart) / (maximum transverse diameter of rib cage)
50
What CT ratios are suggestive of cardiomegaly?
- CT ratio > 0.5 on PA view
- CT ratio > 0.6 on AP view
51
Why might structures look bigger or smaller in radiographs?
- depends on radiographic view
- the further the structure from the radiographic plate, the larger they appear on film
52
How many ribs do humans have?
12 on each side
- ribs 1-10 are connected to the sternum by costal cartilage
- ribs 11-12 are floating
53
Describe how ribs appear on posteroanterior (PA) film.
- posterior ribs are more apparent on PA film, up to 10 visible on full inspiration – recall the further the structure is from the radiographic plate, the larger they appear on film
- anterior ribs are less visible on PA film
54
Describe the different settings on CT.
window level – midpoint of grayscale range
- decrease WL: increase brightness
- increase WL: decrease brightness
55
What is MRI imaging excellent for?
- soft tissue imaging, staging of lung/soft tissue neoplasm
- cardiac imaging
56
What is MRI imaging limited in?
- aerated lung imaging
- bone imaging
(skeletal or air)
57
What are the disadvantages of MRI?
- expensive
- longer examination time
58
What is ultrasound imaging good for?
- 'first line' in heart imaging
- localizes pleural effusions
- characterizes superficial soft tissue lesions on chest wall
59
What are the advantages of ultrasound?
- more readily available
- portable
- inexpensive (less than CT or MRI)
- few contraindications for use
- real-time imaging
- doppler evaluation of organs and vessels
- not adversely affected by metallic objects
- can easily be extended to cover any organ
60
What are the disadvantages of ultrasound?
- user-dependant
- thermal heating or mechanical injury
- unique artifacts
- limited by abnormally large body habitus
61
What is ultrasound imaging limited in?
- cannot see through air or bone – limited in evaluating structures encased in bone
- does not penetrate deeper tissues – cannot evaluate internal structure of tissue
62
What is a pulmonary embolism?
obstruction of the pulmonary artery (or one of its branches) by a substance (often a blood clot or thrombus) that originated in the body
- stops perfusion – no transfer of O2 and CO2
63
What is the best test for pulmonary embolisms?
CT pulmonary angiogram (CTPA)
- uses IV contrast
64
What is vascular doppler ultrasound used for?
estimate blood flow through blood vessels (vasculature)
65
What is artery ultrasound used to assess?
- size and shape
- patency (obstructed/unobstructed)
- rate of flow (velocity)
66
What is artery ultrasound used in?
- renal transplants
- pregnancy – placenta in mom, MCA in fetus
- venous – thrombus (clots)
67
What imaging modality is best for joints?
MRI
68
What is the best imaging modality for soft things, fluid things, and anything that is superficial?
ultrasound
69
What modalities are good for soft tissue (muscle, tendon, ligament) imaging?
- ultrasound
- MRI if you want to visualize more of an area with the same type of soft tissue detail – 3D representation of an area
70
What imaging modality is good for bones?
CT scan
71
Describe the 4 chambers of the heart.
- right atrium: receives deoxygenated blood from the body
- right ventricle: pumps deoxygenated blood to lung for gas exchange
- left atrium: receives oxygenated blood from the lung
- left ventricle: pumps oxygenated blood to the body
72
How is heart size assessed?
using CT (cardiothoracic) ratio
- cardiac size can be assessed on serial films to look for change in size over time
73
What is a cardiac MDCT (multi-detector CT) used for?
to evaluate myocardium and coronary arteries
- detect and quantify coronary calcium prognostic implications
- assess whether you are at a low risk vs. high risk for development of a CAD event
- implications for statin usage
74
What are the advantages of cardiac MDCT?
- high resolution
- fast
- non-invasive
75
What is the best non-invasive test for coronary artery disease (CAD)?
cardiac MDCT is the best test to exclude or detect CAD
- negative CT excludes CAD and patient can be discharged in the acute setting
76
Other than CAD, what other conditions does cardiac MDCT evaluate?
- aortic aneurysms
- dissections
- pulmonary thrombus
(triple rule-out scan in the emergency setting)
77
What is coronary angiography?
small catheter is passed from peripheral vessel into the heart or coronary arteries, then contrast is injected to opacify the lumen of the vessels
- can obtain blood samples (oxygen saturation, assesses intracardiac pressures, detection of cardiac and valvular abnormalities)
78
When is coronary angiography usually done?
after CT (or MRI)
79
What type of assessment is coronary angiography used for?
both diagnostic and therapeutic assessment of coronary arteries
80
What is appendicitis?
inflammation of the appendix – appears larger and thickened
81
What is the clinical presentation of appendicitis?
- classically periumbilical – RLQ pain at McBurney's point, fever, N/V
- typically in children and young adults in their 2nd and 3rd decades of life
82
Is ultrasound a good modality for appendicitis imaging?
ultrasound findings are operator-dependant, and it is often difficult to see the appendix
83
What ultrasound findings are supportive of appendicitis?
- aperistaltic, non-compressible, dilated appendix (> 6 mm outer diameter), with distinct appendiceal wall layers
- confirm finding is appendix: blind-ending and arising from the cecum
84
What other modality is used for appendicitis imaging?
CT
- highly sensitive and specific
- usually done before surgery if it is required
- can be used to rule out other causes of abdominal pain or complicated appendicitis
85
What are the CT findings in appendicitis imaging?
- dilated appendix (> 6 mm lumen), thickened and enhancing wall
- other
86
List the most common causes of death from most common to least common.
- heart disease
- cancer
- COVID-19
- cerebrovascular disease
- alzheimer disease
- diabetes
- influenza/pneumonia
- transport accidents
- assault
- HIV
87
ACC/AHA Chest Pain Guidelines
What is a coronary CTA (CCTA)?
the only Class 1 non-invasive test with Level A evidence for diagnosing CAD and guiding treatment decisions
- first test done for asymptomatic individuals
- effective for diagnosing CAD, for risk stratification, and for guiding treatment decisions
- enables clinicians to take informed action
88
What is atherosclerosis?
thickening or hardening of arteries caused by buildup of plaque in the inner lining of arteries
89
Why is subclinical atherosclerosis important?
recently, many studies have shown that the presence of subclinical atherosclerosis is superior than risk estimate scores in determining the outcomes
90
How can we detect subclinical atherosclerosis?
- carotid ultrasound
- calcium score
- infrarenal abdominal aorta (ultrasound) – below kidneys
addition of imaging to detect subclinical atherosclerosis contributes significantly to predicting outcomes in individuals with and without risk factors
91
How much of a tissue do ultrasound images represent? What affects the anatomy you see?
- images represent only a very thin slice of tissue
- transducer position and orientation affects the appearance of the anatomy you are examining
92
Can ultrasound be used for bone?
under normal conditions, NO
- bones are very strong reflectors of sound waves
- creates acoustic shadows deep to strong reflectors (ie. like flashlights casting shadows on walls)
93
Can ultrasound be used for muscle?
YES
- bundle-like arrangement of muscle creates acoustic interfaces that are visible by ultrasound
- muscle is arranged longitudinally – it will appear differently depending on the orientation of the transducer (ie. long axis vs. short axis)
94
Can ultrasound be used for arteries and veins?
yes
95
How do artery and vein walls appear on ultrasounds?
echogenic (lighter)
96
How do artery and vein lumens appear on ultrasounds?
echopoor (darker)
- lumen contains blood
97
What can be used to characterize the speed and direction of blood flow in arteries and veins?
doppler ultrasound
98
What are Wilson and Jungner's 10 Principles of Screening?
main idea: disease should have significant morbidity/mortality, have understood pathophysiology, and there should be a cost-effective screening test that is acceptable to the population that allows us to offer effective early detection and treatment
- the condition should be an important health problem
- the natural history should be understood
- there should be a recognizable latent or early symptomatic stage
- there is a suitable test (ie. has acceptable specificity/sensitivity, and is safe)
- the test should be accepted by the population that is going to be screened
- there should be an agreed policy for who to treat
- there should be an accepted treatment for patients with recognized disease
- facilities for diagnosis and treatment should be available
- should be cost-effective
- screening should be an on-going process – not a 'once and for all' process
99
What is a pap smear?
screening test for cervical cancer
100
The detection of metastatic disease (ie. cervical cancer) is performed with which imaging modality?
CT or PET/CT
- CT offers structural information based on the density of tissues – can scan the entire body in a few minutes, more accessible than MRI
- PET/CT incorporates the use of radioisotopes attached to compounds that are metabolized by the body (ie. FDG), which also gives metabolic/physiologic information – tumours are usually hypermetabolic and show up bright on PET
- can select for different cancers because they have different markers (use different radioisotopes)
101
Describe the epidemiology of ovarian cancer.
- 9th most common cancer in women
- 5th most common cause of cancer death
- 5-year net survival is 45%
102
What are the risk factors of ovarian cancer?
- advanced age
- genetic mutations (BRCA1 and BRCA2, Lynch syndrome)
- endometriosis
103
What are the protective factors of ovarian cancer?
- pregnancy
- OCPs
- later age of menstruation
- earlier menopause
104
What is the imaging test for ovarian cancer?
ultrasound is usually the starting imaging exam for quick screening – cheap, accessible, and detects ovarian masses well
- scans are acquired transabdominally and endovaginally
MRI pelvis with IV contrast is often acquired to further characterize an ovarian mass
- some complex-looking ovarian cysts can be benign
- the more complex and more solid a lesion is, the more likely to be cancer
105
What imaging modality is used for staging and detection of distant metastatic disease?
CT
106
What is a screening test?
detection of potential disease in asymptomatic individuals
107
What is a diagnostic test?
aiding formal diagnosis of symptomatic individuals
108
What are the benefits of early screening?
- proactive approach – secondary, and tertiary prevention
- early referral and holistic approach to treatment (conservative, medical, surgical)
- support networks, advanced care planning, and goals of care
109
What is primary prevention?
aims to prevent disease or injury before it occurs
- preventing exposure to hazards, behavioural alterations (anti-smoking campaigns, seatbelt legislation, immunizations, eating healthy, exercising, etc.)
110
What is secondary prevention?
aims to reduce the impact of a disease or injury that has already occurred
- identifying disease early to mitigate complications, prevention of reinjury or recurrence (screening tests, daily aspirin in heart attack patients, etc.)
111
What is tertiary prevention?
reduce the impact of an ongoing illness or injury
- managing chronic illnesses to improve function, improving quality of life in those with disease after diagnosis (stroke rehab program, support groups, etc.)
112
What are the goals of screening tests?
- detect disease before it manifests clinically – earlier diagnosis may result in better response to treatment
- improve quality of life for the patient
113
What is the goal of diagnostic tests?
to find the cause of a symptom or sign (ie. using an x-ray to see if a bone is fractured or not)
114
What is sensitivity?
how well a test can detect disease – ability of a test to correctly identify patients with disease
- probability of a positive test, given that the patient HAS the disease
115
What does a high sensitivity mean?
generates few false negatives
- negative test RULES OUT the possibility of having a disease by correctly finding all true positives (ie. no negative results are false)
116
What is specificity?
how well a test identifies individuals who do not have the disease – ability of a test to correctly identify individuals without disease
- probability of a negative test, given that the patient does NOT have the disease
117
What does a high specificity mean?
generates few false positives
- positive test RULES IN those with a disease by correctly finding all true negatives (ie. no positives results are false)
118
Example: Screening test has 80% sensitivity and 70% specificity.
test will correctly identify a positive result for 80% of people who have the disease
- however, this test will not identify a positive result for 20% of people who have the disease, and should have tested positive for the screen (false negative)
test will correctly identify a negative result for 70% of people who do not have the disease
- however, this test will generate a positive result for 30% of people who do not have the disease, and should have tested negative for the screen (false positive)
119
What sensitivity and specificity make the best screening tests?
those that effectively rule out the likelihood of having disease
- ie. high Sn / variable Sp (asymptomatic, unknown = want to pick up cases)
120
What sensitivity and specificity make the best diagnostic tests?
those that accurately rule in or identify those with disease
- ie. variable Sn / high Sp (because we know they are symptomatic = correctly ID)
121
What sensitivity and specificity must we be aware of?
high Sn with low Sp
- increase FALSE POSITIVE rate = inappropriately treating/harming
122
What are the criteria for effective screening programs?
- disease with reversible consequences (poor outcomes)
- treating the disease(s) early (pre-symptomatic) is much better than treating once symptomatic
- prevalence of target disease in population must be high enough to make screening effective = ‘predictive value’ – even if high Sn/Sp, if no one has disease → more issues
- screening test must be low cost, easily administered, safe, acceptable (by everyone)
- after positive screening test, follow-up must be available for thorough diagnostic work-up
123
What is a positive predictive value?
probability that a patient with a positive test result actually has the disease (dependent on disease prevalence)
124
What is the gold standard imaging modality for brain evaluation?
MRI with contrast
- evaluates soft tissues and grey-white brain matter well (brain is soft tissue)
- delineates characteristics of masses (fat, blood, calcifications, etc.)
- provides intravenous contrast to highlight blood supply to mass and rule out other critical diagnostic options (ie. infection, abnormal blood vessels)
- HOWEVER: long scan time, low availability of machines, cannot use if patient has metal implants/pacemakers, etc.
125
What imaging modality is often the first used in brain evaluation?
CT with contrast is often done first instead
- reasonable soft tissues (grey-white matter), good bone view, and fast
- MRI has long scan time, has lower availability of machines, and cannot be used if patient has metal implants/pacemakers, etc.
- MRI may just be done instead if it is already known that something is present
126
Should we screen for asymptomatic intracranial masses?
- more evidence is needed for a concrete decision
- BUT select population screening is valuable – ie. for asymptomatic optic gliomas in children with NF1
127
What is MASLD?
metabolic dysfunction-associated steatotic liver disease
- condition characterized by excessive fat build up in the liver (steatosis) in the absence of excessive alcohol intake
128
What are the risk factors of MASLD?
- type 2 diabetes
- obesity
- metabolic syndrome
129
Why should we care about MASLD?
- 20-30% prevalence in Western countries
- can present as steatosis alone, or lead to inflammation (steatohepatitis/MASH), fibrosis/scarring, cirrhosis, or cancer
- decreased quality of life and increased risk of mortality
130
What is the imaging modality for MASLD screening? What are the pros and cons?
conventional ultrasound
pros:
- acceptable specificity and sensitivity if there is sufficient steatosis
- non-invasive
- low-cost
- readily available
- no radiation
cons:
- body habitus affects scan quality and sensitivity and specificity
- operator-dependent
131
Why is CT generally not considered for MASLD screening?
- higher cost
- less availability
- substantial radiation exposure
132
Why is MRI generally not considered for MASLD screening?
- higher cost
- less availability
133
Should we screen for MASLD?
general consensus is that it is not recommended
- unclear benefit from treatment options
- unclear value of screening tests
- unclear cost-effectiveness
134
What is hepatocellular carcinoma (HCC)?
most common form of liver cancer
135
Describe the epidemiology of hepatocellular carcinoma (HCC).
- 3rd leading cause of cancer-related deaths in 2020
136
What are the risk factors of hepatocellular carcinoma (HCC)?
- cirrhosis
- hepatitis B and C
- alcohol intake
- MASLD
137
What is the imaging modality of choice for hepatocellular carcinoma (HCC) screening? What are the pros and cons?
ultrasound
pros:
- inexpensive
- non-invasive
- well-tolerated
- readily available
cons:
- sensitivity depends on operator experience
- certain areas of liver are harder to visualize using ultrasound
- lower sensitivity for early-stage HCC
- affected by body habitus
138
What other imaging modalities are used for hepatocellular carcinoma (HCC) screening?
- contrast-enhanced CT
- MRI
- abbreviated MRI
139
What are the pros and cons of contrast-enhanced CT for hepatocellular carcinoma (HCC) screening?
pros:
- higher sensitivity
- better at detecting early stage HCC
cons:
- radiation exposure
- adverse events due to contrast
- expensive
140
What are the pros and cons of MRI for hepatocellular carcinoma (HCC) screening?
pros:
- higher sensitivity
- better at detecting early stage HCC
cons:
- expensive
- time consuming
- some patients claustrophobic
- some implants incompatible
141
Should we screen for hepatocellular carcinoma (HCC)?
consensus among international guidelines is that screening should be performed in all patients with cirrhosis – ultrasound every 6 months
142
What are benign cells?
(non-cancer cells) cells that only grow locally and cannot spread by invasion or metastasis
143
What are malignant cells?
(cancer cells) cells that invade neighbouring tissues, enter blood vessels, and metastasize to different sites
144
Is CT a good modality for monitoring cancer therapy?
in CT scans, you cannot tell if an entire blob is cancer cells
- need to do PET scan to localize cancer cells
145
What are some challenges in oncological imaging?
- radiation exposure concerns
- accessibility and affordability issues
- addressing false positives and negatives
146
What is a coronary computed tomography angiography (CTTA)?
heart CT with contrast
147
What imaging modalities are used in oncology? what are they used for?
ultrasound, CT, MRI, and PET are 'mainly' used for initial imaging, treatment response, and monitoring recurrence
148
What imaging modality is useful for cancer staging?
PET scan is often very useful for identifying where the malignancy has spread
- above vs. below diaphragm (chest vs. abdomen)
- lymph nodes (which drain various organs and sites of the body)
- adjacent structures/organs
149
What is grading in oncology?
pathology diagnosis, once tissue has been sampled and is visualized under a microscope
