Cancer imaging Flashcards
Medical imaging
process of creating and interpreting images of body morphology and fx for the explicit purposes of pateint examination and intervention
types medical imaging
- structural/ morphological
- Funcitonal
- Molecular imaging
Structural imaging
aka morphological imaging
this is 99% of imaging done in vet med
- look for changes in size, shape, opacity
- look to see if tissue normal or if it has changed
- best for diagnosing dx that produces morphological changes (developmental abnormalities, neoplasia, infection, trauma)
- also used to observe functional disturbances (joint laxity or stiffness, difficulty swallowing, inability to urinate)
Structural imaging is not helpful when disease
- does not produce morphologic change (might still be worth imagine to rule out other dxs like neoplasm that do though)
- does not produce changes at a time that is clinically relevant (early diagnosis = key so if see it in later stage this isn’t helpful to improving prognosis)
- does not produce morphologic changes that are specific for a case (organs can often have same response regardless of insult so for example increased liver can be caused by MANY things so we know its enlarged but that doesn’t tell us what specifically is causing it)
Functional imaging
- provides image that display info about physiologic activities or organ regardless of morphologic changes
- best for answering how well is an organ fxing (ex renal excretion, neuronal activity, lung ventilation and perfusion)
how does functional imaging work
physiologic activities measured directly or indirectly by detecting secondary changes in metabolic activity, hemodynamic responses, and chemical composition
- ex. look at neuronal activity not by looking at nerve activity but by looking at blood flow to brain which we know is associated
renal syntigraphy
get radioactive isotope that binds to radiopharmaceutical that goes to kidney and can quantify how fast kidney excretes isotope from body; use this to determine how much fx we are getting from 2 different kidneys; tells us if we can take a kidney out if mass on it if other one fxing enough to avoid renal failure ect.
how did they image cat brain for blood flow related to blindness / deafness post sx
functional imagine
image non-random moving water using diffusion tensor imaging
functional image
molecular imaging
- production of images that depict biological processes, especially molecular pathways that take place at cellular and sub cellular level like angiogenesis and apoptosis or the expression and activity of specific molecules like proteases and protein kinases
- structural and functional imaging often show the end results of these molecular alterations
how does molecular imaging work
- uses endogenous molecules or exogenous agents to visualize, characterize, and measure biological processes
pet scans
functional imaging
molecular imaging benefits
- early detection of dx (often before gross morphologic or functional changes)
- differentiating between benign and malignant neoplasms
- predicting tumor response to specific chemotherapies
- monitoring cell growth and death as a means to follow treatment response
- more specific diagnoses
- better delineation of dx extent
- these are all potentials right now**
limitations of molecular imaging
lack of specific targeting agents that are effective; these are becoming more popular and will become imaging of the future
hybrid imaging
combine images of two different imaging modalities (ex pet scan = functional combine with MRI= structural)
imaging technology used for vet cancer pateints
- radiography
- U/S
- Scintigraphy
- MRI
- CT
- PET
goals of cancer imaging
- monitor treatment response or dx progression
- determine extent of dx (figure out boundaries of mass so can spare as much healthy tissue as possible)
- Establish prognosis (is there metastasis?)
- Make a diagnosis (is problem traumatic, inflammatory, neoplastic ect.)
- Guide intervention (catheter/ needle to tumor)
screening test
early detection: test performed in healthy patient with no sign of dx to look for dx in case it is there (ex hip or elbow dysplasia); mammography in humans
Diagnostic test
clinically affected: test preferomed on affect individual
extend of dx
- primary cancer
- staging
- secondary effects
extend is important bc need to avoid as much healthy tissue as possible when making treatment plan to maintain best QOL; looks to see if there is distant spread tumors
metastasis
invasion
survive circulation
evade immune system
arrest in target tissue (size dependent trapping, specific adhesion molecules)
adhesion and early survival at distant sites
modulation of novel environment
angiogenesis
ossifying pulmonary metaplasia
VERY opaque for v small noodles (less than 5mm); these can’t be cancer be soft tissue bc mineral opacity so they are either end on blood vessel or they are mineral opacity (which s going to be due to calcification due to degenerative change)
Secondary effects
- obstruction
- functional tummors
- paraneoplastic tumors
functional tumors
producing things, can lead to further issues in the body ex. tumor secreting ACTH won’t respond to negative feed back loop so will just overproduce ACTH
paraneoplastic syndrom
neoplasm associated alteration in body structure or function that occurs distant to the tumor (tumors can have different chemical affects on body and effect it in a lot of different ways; animals may come in with signs of dx but that dx may be caused for cancer so need to know which dxs can have paraneoplastic syndromes so know what to look for)
ex. hypertrophic osteopathy
