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8 Cards in this Set
- Front
- Back
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Indications for bone mineral analysis:
Which imaging studies are terrible for bone densitometry? Three most common imaging studies? |
long-term steroid use, primary hyperPTH, anorexia, EtOH, assessment of early menopausal bone loss, osteoporosis dx
U/S, MRI single XR, dual XR absorptiometry (most commonly used), quant CT |
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Explain dual XR absorptiometry:
Cost of average bone density scan: Measurement most often used in bone densitometry: Common sites for scanning: |
most commonly used, two energy levels created by filter/generator, good precision/accuracy, low radiation
$300 to patient, $100 Medicare bone mineral density (g/cm2) femoral head, hip, L-spine |
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Explain T score:
Considerations in scoring: |
T score = young adult data and SD-
>-1.0 - normal -1 - -2.5 = osteopenia <-2.5 = osteoporosis elevated - check for osteophytes, diffuse sclerosis low - lesion 3 regions don't match fractures |
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Which imaging study is best for pituitary imaging?
What is unique about the pituitary on MRI? Mass effect of a pituitary tumor will often affect which senses? |
MRI - sagittal/coronal positions - with/without contrast
pituitary will often enhance on MRI vision - proximity to optic chiasm |
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<10 mm size, confined to gland, usually functional:
most common type? Which imaging is a must for these tumors? Why? |
pituitary microadenoma
prolactinoma dynamic imaging - tumors will take up contrast differently than normal tissue |
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Characteristics of pituitary macroadenomas:
What is empy sella? |
>10 mm, grows out of sellae; can be non-functioning, usually symptomatic from mass effect; heterogenous, cystic
defect in sella diaphragm allows CSF into sella - common anatomic variant, 10% of adults - no clinical significance, asymptomatic |
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Massive hemorrhage into pituitary adenoma causing infarction, necrosis:
Symptoms? Occurring post pregnancy: Appearance on MRI? What else is bright on T1? |
pituitary apoplexy
sudden onset N/V, HA, visual loss Sheehan's syndrome bright on T1 fat, blood, contrast |
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Usual first step in adrenal imaging?
Good for infant adrenal studies: How to tell malignant masses on adrenal gland MRI? Appearance of pheochromocytoma on T2 MRI? Fluid appearance on T1? |
CT - first and often last step
MRI best, U/S good more heterogeneous, lighter than retroperitoneal fat (density/enhancement) "Light bulb" - lights up dark |
