18: Radiology of Metabolic Bone Disease - Yoho

Question 1

_____ produce osteoid matrix an amorphous ground substance and collagen matrix

Answer 1

osteoblasts

Question 2

Bone is made of …

Answer 2

ions having crystallized (hydroxyapatite) on the osteoid matrix forming the bone unit

Composition:
Water (8%)
Organic substance (21%)
Inorganic substance (71%)

Question 3

cortical bone black =

white =

Answer 3

MRI

CT scan

Question 4

Osteoblasts make osteoid from ______

Answer 4

albumin

process is aided by vitamin A and C, estrogen and growth hormone

Question 5

osteogenesis is stimulated by … (2)

Answer 5

Stimulated by a low oxygen tension and acidic environment

Aided by a local alkaline environment

why you measure alkaline phosphatase**

Question 6

Mineralization or calcification is triggered by

Answer 6

the high affinity of osteoid matrix for hydroxyapatite

Question 7

dissolution of bone

Answer 7

Osteolysis

Osteoclasts and PTH hormone stimulate an acid phosphatase to proteolytic action on the osteoid crystals

Question 8

Osteoclasts are stimulated by

Answer 8

Osteoclasts are stimulated by high oxygen tension

Aided by an acidic environment and a decrease in calcium and phosphate ions

Question 9

a descriptive term for a loss of bone density observed radiographically

Answer 9

Osteopenia

**50% bone loss is clinically significant
30% bone loss is radiographically detectable

Question 10

quantification of bone loss tools

Answer 10

DEXA or ultrasound as T-scores and Z-scores

Question 11

T-Score

related to young adult

Answer 11

normal— Bone density is within 1 SD (+1 or −1) of the young adult mean.

low bone mass — Bone density is between 1 and 2.5 SD below the young adult mean (−1 to −2.5 SD).

osteoporosis —Bone density is 2.5 SD or more below the young adult mean (−2.5 SD or lower).

severe oseoporosis — Bone density is more than 2.5 SD below the young adult mean, and there have been one or more osteoporotic fractures.

Question 12

Z- Score

Answer 12

age and gender matched

Question 13

define generalized osteoporosis

Answer 13

Definition: decrease in bone density (mass per unit volume) of mineralized bone

clinical and lab correlation required for classification

Question 14

radiographic findings for osteoporosis

Answer 14

Diminished bone density

Cortical thinning with endosteal resorption

Preferential resorption of transverse trabeculae

Anterior wedging of the vertebral bodies (dowager’s hump)

Question 15

how does scurvy cause generalized osteoporosis?

Answer 15

Vitamin C deficiency

Osteoblasts fail to produce osteoid

Lack of mineralization

Alcoholism/starvation

Slow wound healing, peau de orange

Hemorrhagic cutaneous lesions

Question 16

radiographic findings for scurvy

Answer 16

White line of scurvy

Bone spicules at metaphyseal margins (Pelkin’s sign) (small arrows of washed out bone)

Corner sign (washed out bone in corner)

Trumifield zone

Epiphyseal displacement

Ringed epiphysis (preferential washing out of epiphysis)

Cortical deossification with ground glass appearance

its going to be generalized throughout the body

Question 17

osteomyelitis and tumors cause what type of osteoporosis

Answer 17

localized osteolytic osteoporosis

Question 18

CRPS chronic regional pain syndrome osteoporosis

Answer 18

sudeck’s atrophy - localized osteoporosis

Question 19

early –> final lcoalized osteoporosis radiographic findingings

Answer 19

Early: spotty loss of density with irregular rarefaction, loss of sharp outline of the articular cortex
Later: periarticular deossification
Final: uniform loss of density with a thin well-defined cortex

**In tumors and infection the process if referred to as lysis (lytic lesions)

Question 20

CRPS complex regional pain syndrome stages

Answer 20

Stage I: Acute
Stage II: Dystrophic
Stage III: Atrophic

Question 21

describe sudeck’s atrophy

Answer 21

Patchy osteoporosis
Accentuated joints
Subchondral bone resorption
Ground-glass appearance

Question 22

Defect in calcification with increased accumulation of uncalcified osteoid

Answer 22

Osteomalacia/Rickets

Vitamin D deficiency
Renal tubular insufficiency
Non-resorptive process**
Skeletal deformity*

Question 23

radiographic findings osteomalacia

Answer 23

Generalized decrease in bone density

Loss of trabecular detail

Cortex may be thin and lack definition

Skeletal deformities

Looser’s lines (milkman’s false fx)

Question 24

radiographic findings Rickets

Answer 24

Widening of epiphyseal plate with a frayed appearance

Irregular zone of provisional calcification

Metaphyseal cupping

Milkman’s fracture

Question 25

radiographic features of endocrinopathies

Answer 25

Subperiosteal resorption Generalized loss of bone density Terminal tuft resorption Brown tumors** Soft tissue calcifications

Question 26

name the marrow packing disorders

Answer 26

Thalassemia Multiple Myeloma Leukemias ``` Radiographic findings: Hyperplastic marrow response Expansile areas of lytic destruction Periosteal new bone formation Pathologic fracture ```

Question 27

a descriptive term for an increase in bone density observed radiographically

Answer 27

Osteosclerosis Mechanisms responsible: Failure of primary spongiosa to be absorbed in the metaphysis during enchondral bone formation Errors of internal modeling of compacta and spongiosa Stimulation of normal endogenous osteoblasts to form excessive new bone

Question 28

describe paget's disease

Answer 28

Incidence: 5th decade Sites: skull, spine, pelvis and major long bones Skeletal pain and deformity (increase in size) tests: Alk Phosphatase, N-telopeptides and deoxypyridinoline

Question 29

radiographic findings for paget's disease

Answer 29

Lytic phase - Destructive changes - Flamed shaped-lesions*** - Osteoporosis circumscripta Sclerotic phase - Bizarre new bone formation Combined phase Malignant transformation (osteogenic sarcoma)

Question 30

Failure to absorb primary spongiosa

Answer 30

Osteopetrosis

Question 31

radiographic findings osteopetrosis

Answer 31

- - Uniform increase in bone density - - Loss of distinction between cortical and medullary bone - - Erlenmeyer flask appearance of tubular bones - - Bone within bone appearance - - Fractures are common

Question 32

radiographic findings osteopoikilosis

Answer 32

- - Multiple round/ovoid bone densities - - Few mm to several cm - - Non-progressive - - Metaphyseal and epiphyseal involvement in long bones Hereditary bone disorder Unknown etiology Incidental finding

Question 33

Heterotrophic soft tissue ossification

Answer 33

Myositis Ossificans will have hx of trauma Radiographic Findings: - - Ill-defined calcifications - -Organization into bone - - Follows axis of muscle - - Adjacent periosteum may show changes - - Differentiate from sarcoma