rads mt 2

what are the goals of screening

early detection of disease before clinical manifestation and improve patient quality of life

screening

tests to detect disease before clinical manifestation

diagnostic tests

tests to find the cause of a symptom/clinical manifestation

principles of screening

1. must be important health problem

2. natural history should be understood

3. has a recognizable latent or early symptomatic stage

4. has a suitable test that is accepted by the population

5. there must be a policy for who to treat

6. options must be available for diagnosis and treatment

7. cost effective and ongoing process

consequences of screening

1. false positives: false reassurance and delayed treatment

2. false negative: anxiety and stress

3. over-diagnosis and over treatment

what is test sensitivity

how well a test can detect a disease

what is test specificity

how well a test identifies patients who DO NOT have disease

a highly sensitive screening test produces:

few false negatives

a highly specific screening test would produce:

very few false positives

what is a false negative

when the test says you don’t have a disease when you do have it

what is a false positive

when the test says you do have a disease but you don’t have it

liver functions

• removes toxins

• stores vitamins and glucose

• makes bile

• makes blood clotting regulating factors

metabolic dysfunction associated steatotic liver disease (MASLD)

excessive fat buildup in the liver in the absence of excessive alcohol intake

risk factors for MASLD

type 2 diabetes, obesity, metabolic syndrome

steatosis

abnormal buildup of fat inside an organ

what can MASLD present as

inflammation, steatosis, fibrosis, cirrhosis, cancer

how does MASLD decrease quality of life and increase risk of mortality

• buildup of food in the abdomen due to lack of liver enzymes

• lack of blood clotting elements

• loss of cognitive function

cons of blood tests for MASLD screening

lack sensitivity, 78% of people with MASLD may have normal liver enzymes

MASLD screening

blood tests, ultrasound, liver fat quantification, ultrasound elastrography, CT, MRI, MRI elastrography

pros of ultrasound screening for MASLD

• acceptable sensitivity and specificity

• non invasive and no radiation

• cheap and accessible

cons of ultrasound screening for MASLD

anatomy can affect sensitivity and specificity, operator dependent

what does a hypoechoic liver indicate

high fat in the liver → fatty liver disease

what is liver fat quantification

quantifying the attenuation of a sound beam when it hits the liver

what is ultrasound elastography

using ultrasound to determine liver stiffness

is CT good for MASLD screening

no

why is CT not preferred for MASLD screening

expensive, inaccessible, big radiation

is MRI good for MASLD screening

no

why is MRI not good for MASLD screening

expensive and inaccessible despite being the most accurate

should MASLD be regularly screened in the general population?

no

why not regularly screen for MASLD in the general population

unclear benefit from treatment options, unclear value and cost-effectiveness

EASL 2016 screening guidelines for MASLD

obesity, metabolic syndrome, diabetes, elevated liver enzymes

canadian association for the study of the liver screening guidelines

t2d, obesity, hepatic steatosis, family history

what is hepatocellular carcinoma (HCC)

most common form of liver cancer

risk factors for HCC

cirrhosis, hep B and C, alcohol intake, MASLD

what is the third leading cause of cancer related deaths

HCC

imaging options for HCC

ultrasound, contrast CT, MRI

what is the preferred imaging modality of choice for HCC

ultrasound

what is the preferred imaging modality of choice for MASLD

ultrasound

cons of ultrasound for HCC screening

• certain areas of the liver are harder to visualize

• lower sensitivity to early stage HCC

• affected by body habitus

• operator dependent

pros of contrast CT for HCC screening

higher sensitivity and better at detecting early stage HCC

cons of contrast CT for HCC screening

• high radiation

• expensive

• adverse affects of contrast agents

pros of MRI for HCC screening

higher sensitivity and better at detecting early stage HCC

cons of MRI for HCC screening

expensive, time consuming, machine may be incompatible with patient

pros of abbreviated MRI for HCC screening

higher sensitivity, better at detecting early stage HCC, faster, cheaper

cons of abbreviated MRI for HCC screening

low data comparing to ultrasound, may require a recall for a complete exam

which stage of HCC can be cured

early stage

HCC screening guidelines

ultrasound every 6 months for patients with cirrhosis

HCC screening populations for patients w/o cirrhosis

patients with hep c or b, advanced fibrosis, family history of HCC, patients of asian or african descent

primary lung cancer

broad term referring to primary lung malignancies

what is the cause of lung cancer for 90% of cases

smoking tobacco

what is the most commonly diagnosed cancers in BC

lung cancer

how is smoking history measured

pack-years: number of packs smoked daily x number of years smoking

symptoms of lung cancer

• asymptomatic for 50% of cases

• cough/wheeze/shortness of breath

• hemoptysis

• pneumonia

• pleural effusion

why is lung cancer screening important

can detect the lung cancer before it becomes symptomatic and more serious

when do lung cancer symptoms appear

typically when the disease is at an advanced stage and has spread

who to screen for lung cancer

high risk, asymptomatic populations:

• 55-74 yrs old

• currently smoke or used to smoke <15yrs ago

• have a smoking history of >30 pack-years

how to screen for lung cancer

lose dose CT (LDCT) every year for 3 consecutive years

what are you looking for during a lung cancer screening

non-calcified pulmonary nodule

types of lung nodules

solid and subsolid (part-solid, ground glass)

which nodule has the highest probability of malignancy

subsolid nodules

rank the nodules from most to least probability of malignancy

nonsolid> part-solid > solid

growth rate of different lesions

non-solid < solid

is it easier to find peripheral or central nodules

central nodules

what is used for nodule detection

double reader technique using CAD

what do we measure when looking at nodules

size, shape, and growth

how is pulmonary nodule size measured

manual measurement of max diameter, volumetric measurement

when is increased nodule size flagged

increase in mean diameter of 2mm or more for <15mm nodules

15% increase in mean diameter for nodules >15mm

considerations for measuring subsolid nodules

• measurement is more complex

• if subsolid diameter is stable with solid component increasing → sus asf

main way of obtaining lung lesions

imaging guided biopsy using US, CT, or fluoroscopy

what is planetary health

analyzing and addressing how human disruptions to the earth affects human health

what is the triple planetary crisis

climate change, pollution, and biodiversity loss

changes with the biggest GHG emission impacts

living car free, avoiding a transatlantic flight, plant-based diet, and recycling, divesting from fossil fuels

direct contributors to healthcare GHG emmisions

building heating and anesthetic gases

indirect contributors to healthcare GHG emissions

purchased energy/electricity and supply chain

what is mitigation

reduce emission of GHG into the atmosphere and stabilize GHG levels to give ecosystems time to adapt to climate change impacts

framework for sustainable healthcare in radiology

reduce demand, match supply of health services to demand, reduce emissions from supply of health services

rank the imaging tests use of energy from most to least

interventional > PET > MRI > CT > US

optimizing MRI energy use

• power off at night

• adjust sequence and protocol length

• optimize patient scheduling

optimizing PACS energy use

turning off PACS, laser printers and computers after hours

ways to reduce, reuse/repurpose, and recycle in radiology

• reduce IR trays and use of disposable supplies

• reuse surgical gowns

• repurpose reusable gowns for nonsterile PPE

• recycle leftover contrast

secondary prevention

identifying disease early to mitigate complications

tertiary prevention

improving quality of life in those with disease

benefits of early screening

• detect disease at early stages for better survival rates

• early referral and holistic approach to treatment

• support networks, advanced care planning and goals of care

what does high sensitivity and low specificity increase the rate of?

false positive rate = doing unneeded treatment

best screening test

high sensitivity, variable specificity to rule out likelihood of disease

best diagnostic test

high specificity, variable sensitivity to rule in disease

what is the gold standard of brain imaging

contrast MRI

why is contrast MRI the golden standard for brain imaging

good soft tissue contrast and intravenous contrast to highlight blood supply to masses

cons of contrast MRI

long scan time, inaccessible, incompatible with some patients

determinants of brain tumor type

age, genetic conditions, prior radiation exposure

should we screen for asymptomatic brain masses and why

no

• no clear benefit to screening + expensive

• overdetection bias: discovering benign disease = overtreatment and patient stress

• lead time bias: detecting too early creates prolonged survival timeline

• length time bias: bias that states that slow growing tumors are more likely to be detected than rapidly growing tumors

population specific screening of intracranial masses

screening for optic gliomas in NF1 patients, patients with genetic conditions, prior cancers, or after head radiation therapy

occurrence of breast cancer in women

• 85% of breast cancers occur in women w/o family history

• risk of breast cancer doubles with first-degree relative with breast cancer

controllable risk factors for breast cancer

• combined hormone therapy post menopause

• fat and alcohol consumption

• lack of exercise

• smoking

• obesity

uncontrollable risk factors

• genetics

• chest wall radiation

• dense breast tissue

• family history

• previous atypical cells

• early menstruation or late menopause

alcohol guidelines

2 drinks per week. 3-6 drinks per week increases risk of breast cancer, 7+ drinks per week increases risk of CVD

breast cancer screening

• self and clinical breast examination

• mammography, contrast mammography

• US

• MRI

• molecular breast imaging

why not thermography

can detect superficial cancers but not deeper ones

optimal breast screening protocol

• annual mammogram starting at 40 and continuing after menopause

• know your breast density

• US/MRI/contrast mammography

additional screening guideliners

• high risk women

• dense breast havers

• genetic mutations