Unit 1

Question 1

Conventional Tomography

Answer 1

Used to evaluate structures or abnormalities.
Blurs out objects above and below plane of interest
Fulcrum/pivot is level of interest

Question 2

Computed Tomography (CT, CAT)

Answer 2

Most images obtained in axial plane
Excellent spatial relationships
Based on tissue attenuation
Components - Gantry houses tube and sensors; table; x-ray generator; data processor
Cross-sectional cuts 0.2-1.3cm
Tissues expressed in Hounsfield Units (Hu)

Question 3

Bone Scintigraphy

Answer 3

Radionuclide bone scanning (skeleton, heart, lung, kidneys, brain)
Organ/system uptake of Technetium-99m methylene diphosphate (99mTc-MDP) is MC radioactive agent
Extremely sensitive; lacks specificity
Look for “hot spots”

Question 4

Magnetic Resonance Imaging (MRI)

Answer 4

Based on re-emission of an absorbed radiofrequency while pt is in strong magnetic field
Spin echo T1 & T2 images, STIR, FLAIR, FSE, GRE are ex. Of pulse sequences
T1 is fat sequence; T2 is water sequence

Question 5

Categorical Approach to Bone Disease Pneumonic: CATBITES

Answer 5

Congenital
Arthritis
Trauma
Blood
Infection
Tumor
Endocrine, nutritional, metabolic
Soft tissue

Question 6

Number of lesions: Solitary lesion

Answer 6

Simple Bone Cyst (SBC)

Osteosarcoma

Question 7

Number of Lesions: Multiple Lesions (Multiplicity)

Answer 7

Metastatic Disease
Multiple Myeloma
HME (Hereditary Multiple Exostosis)
Enchondromatosis

Question 8

Monostotic

Answer 8

Single bone

Suggests tumor or infection

Question 9

Polyostotic

Answer 9

Multiple bones

Question 10

Osteoma (location)

Answer 10

Frontal sinus (skull; common location)

Question 11

Hemangioma (location)

Answer 11

Spine (MC benign tumor of spine)

Question 12

Bone marrow tumors

Answer 12

Myeloma

Lymphoma

Question 13

Chordoma (location)

Answer 13

Cranial and caudal cord limits
Remnants of primitive notochord

Most tumors are radiolucent

Question 14

Diaphyseal tumors

Answer 14

Ewing’s Sarcoma

Multiple Myeloma

Question 15

Diametaphyseal tumors

Answer 15

NOF (Non-Ossifying Fibroma)

Question 16

Metaphyseal tumors

Answer 16

Osteosarcoma (malignant)

Simple Bone Cyst (SBC; benign)

Question 17

Epiphyseal tumors

Answer 17

Chondroblastoma

Question 18

Metaphyseal-Epiphyseal Tumors

Answer 18

Giant-Cell tumor

Question 19

Axial orientation: Central

Answer 19

Centrally located on both AP and Lat Views

Ex: SBC, Chondrosarcoma, Fibrous Dysplasia

Question 20

Axial orientation: Eccentric

Answer 20

Still medullary in location, but not centered in 1 view

Ex: Giant Cell, Chondromyxoid fibroma, ABC (Aneurysmal Bone Cyst)

Question 21

Axial orientation: Cortical

Answer 21

Overlies the cortex on at least one view; may see cortical thickening, expansion, destruction, periosteal response

Ex: Osteoid osteoma, FCD (Fibrous Cortical Defect)

Question 22

Axial orientation: Parosteal

Answer 22

Close approximation but definite separation from majority of underlying bone; notable lesion in soft tissue w/ little bony abnormality

Ex: Juxtacortical chondroma, parosteal osteosarcoma

Question 23

Axial orientation: Extraosseous (Soft Tissue)

Answer 23

Distant location from bone or adjacent cleft separates mass from cortical surface

Ex: Myositis ossificans (aka Heterotopic Bone Formation)

Question 24

Size and shape of lesion: malignant

Answer 24

Most malignant or aggressive lesions tend to be large at time of discovery ( >6cm). Exceptions: Fibrous dysplasia; SBC, ABC, Giant-Cell.

Slow-growing lesions usually progress along long-axis of bone. Fast growing tumors are often pleomorphic or round-ish in shape.

Question 25

Behavior of Lesion

Answer 25

Bone lesions may be osteolytic, osteoblastic, or mixed. Majority of bone tumors are osteolytic. ~30-50% of cancellous bone must be destroyed to see on x-ray. Three patterns of destruction: geographic; moth-eaten; permeative

Question 26

Pattern of Bone Destruction: Geographic

Answer 26

Least aggressive pattern. Circumscribed & uniformly lytic Usually solitary >1cm Usually sharply marginated May be trabeculated (soap bubble appearance) Indicative of slow-growing lesion (usually benign) Ex: ABC (Aneurysmal Bone Cyst)

Question 27

Pattern of Bone Destruction: Moth-Eaten

Answer 27

``` Multiple small or moderate sized lucencies that may or may not be poorly marginated (2-5cm) “Punched-out” appearance Longer ZOT (zone of transition) Indicative of aggressive lesions Metastasis Ex: NHL (Non-Hodgkin’s Lymphoma) ```

Question 28

Pattern of Bone Destruction: Permeative

Answer 28

Multiple holes <1mm in size Poorly demarcated, not easily separated from normal bone Areas of destruction my coalesce Wide ZOT Indicative of very aggressive lesion Ex: NHL (Non-Hodgkins Lymphoma); Multiple Myeloma

Question 29

Margination

Answer 29

Refers to margin of lesion Ex: Imperceptible, sharp, wide, narrow

Question 30

Sharp Margination

Answer 30

AKA: Narrow ZOT; definite Line of demarcation between lesion and normal bone is well-defined; may be sclerotic Indicative of slow-growing process Ex: Fibrous dysplasia; SBC

Question 31

Imperceptible Margination

Answer 31

AKA: Wide ZOT; ill-defined; hazy Gradation between lesion and normal bone occurs gradually with no distinct line of demarcation Indicated aggressive or malignant process Ex: Metastasis; Infections

Question 32

Cortical Integrity: Appearances

Answer 32

Key factor in assessing growth rate ``` Cortical Expansion Cortical Erosion Cortical Thinning Cortical Destruction Cortical Saucerization Cortical Thickening ```

Question 33

Cortical Expansion

Answer 33

Result of progressive endosteal erosion together with periosteal bone formation. Bulging of an intact cortex; slow continued growth, generally benign Ex: Giant-Cell (when it extends to articular surface); ABC

Question 34

Cortical Erosion

Answer 34

Slow growing medullary tumors with lobulated or scalloped appearance Endosteal scalloping - cartilaginous and fibrous tumors, myeloma Ex: Enchondroma; Chondrosarcoma

Question 35

Cortical Destruction

Answer 35

Strong indicator of aggressive bone disease. Easier to identify than destruction w/in medulla May see moth-eaten permeative destruction Periosteal response and/or soft tissue mass

Question 36

Cortical Thinning

Answer 36

Thinning w/out loss of integrity, usually denotes slow growth Ex: osteoporosis, tumors (localized)

Question 37

Cortical Thickening

Answer 37

Thickening of cortex. May be localized Ex: osteoid osteoma; stress fx; Paget Disease

Question 38

Cortical Saucerization

Answer 38

Saucerized destruction of cortex Ex: Ewing’s Sarcoma

Question 39

Tumor Matrix Types: Osseous

Answer 39

Tumor New Bone - New bone produced by osteogenic tumors - fluffy, cloud-like appearance - Ex: Osteosarcoma; calcification of osteoid Reactive New Bone - Body lays down new bone in response to stimulus - Ex: Degenerative Sclerosis; metastasis

Question 40

Tumor Matrix Types: Cartilage

Answer 40

Endochondral calcification of chondroid nodules. Stippled, flocculent, arc or ring-like, popcorn-like, comma shaped Ex: Chondrosarcoma, endochondroma, osteochondroma

Question 41

Tumor Matrix Types: Fibrous

Answer 41

Radilucent or slightly hazy. Smoky, hazy, ground glass* due to calcification of osteoid. Often difficult to identify Ex: Fibrous dysplasia

Question 42

Tumor Matrix Types: Fat

Answer 42

If intraosseous, it is hard to identify on plain-film

Question 43

Periosteal Response

Answer 43

Bone forming irritants include: blood, pus neoplasm, edema, granulation tissue New bone is formed by cambium layer; generally a 10-21 day latent period

Question 44

Laminated Periosteal Response

Answer 44

AKA: Layered, onion-skin, lamellated Alternating layers of radiopacity and lucency (may eventually form solid appearance). Cyclical variation in growth Ex: Ewing’s Sarcoma, Osteosarcoma

Question 45

Spiculated Periosteal Response

Answer 45

AKA: Perpendicular, brushed whiskers, hair-on-end, sunburst Fine linear spiculations of new bone radiating from point source. Usually indicative of very aggressive bone tumors. Ex: Osteosarcoma

Question 46

Codman’s Triangle

Answer 46

AKA: Codman’s Angle, periosteal cuff, periosteal buttress Periosteal new bone at peripheral lesion-cortex junction Results from subperiosteal extension of lesion