Chapter 23: Recognizing Abnormalities Of Bone Density

Question 1

What is an orthogonal view?

Answer 1

Two X-rays taken at 90 degrees to each other

Question 2

What are examples of Increased Bone Density?

Answer 2

Diffuse osteoblastic metastases

Localized osteoblastic metastases

Avascular necrosis of bone

Paget Disease

Question 3

What are examples of decreased bone density?

Answer 3

Osteoporosis

Hyperparathyroidism

Localized osteoblastic metastases

Multiple Myeloma

Osteomyelitis

Question 4

What diseases will cause focal increase in bone density?

Answer 4

Carcinoma of the prostate

Avascular necrosis of bone

Paget Disease

Question 5

What is Technetium-99M used for?

Answer 5

The radionuclide used to tag MDP in bone scans because is affixes to bone surface

Question 6

What does activity in bone depend upon?

Answer 6

Blood supply and rate of bone turnover

Question 7

What processes may produce false-negative scans?

Answer 7

Those with extremely high or extremely low bone turnover

Question 8

What do osteoblastic lesions show on Xray?

Answer 8

Increased activity by uptake of radiotracer

Question 9

What is the initial study of choice when looking for myeloma lesions? Why?

Answer 9

Conventional X-rays because the bone is much less sensitive in detecting multiple myeloma

Question 10

Bone scans are…

Answer 10

Highly sensitive and not very specific; positive scan will require another imaging procedure to rule out nonmalignant cause of positive bone scan

Question 11

What diseases cause INtravascular necrosis of bone?

Answer 11

Sickle Cell Disease

Polycythemia Vera

Question 12

What diseases cause Vascular Necrosis of Bone?

Answer 12

Vasculitis induced by lupus or radiation

Question 13

What diseases cause Extravascular Necrosis of bone?

Answer 13

Trauma

Question 14

What diseases cause idiopathic avascular necrosis of bone?

Answer 14

Exogenous steroids and Cushing Disease

Legg-Calve-Perthes Disease

Question 15

What diseases cause a diffuse decrease in bone density?

Answer 15

Osteoporosis

Hyperparathyroidism

Question 16

What is primary hyperparathyroidism?

Answer 16

Caused by single adenoidal in 80-90% of patients and almost always results in hypercalcemia

Question 17

What is secondary hyperparathyroidism?

Answer 17

Caused by hyperplasia of glands secondary to imbalances in calcium and phosphorous levels

Seen mostly with chronic renal disease

Question 18

What is tertiary hyperparathyroidism?

Answer 18

Occurs in patients with long-standing secondary hyperparathyroidism

Patient has autonomous hypersecretion of PTH causing hypercalcemia

Question 19

Diseases that cause focal decrease in bone density?

Answer 19

Metastatic Disease to Bone

Multiple Myeloma

Osteomyelitis

Question 20

What are the two categories of metastases to bone?

Answer 20

Osteoblastic and osteoblastic

Question 21

What is osteoblastic metastases to bone?

Answer 21

Stimulates the production of new bone

Question 22

What are osteolytic metastases to bone?

Answer 22

Destroy bone

Question 23

Where are metastatic bone lesions uncommon and if they are present here, what are they caused by?

Answer 23

Distal to the elbow or knee

Caused by lung or breast cancer

Question 24

What is the study of choice for detecting skeletal metastases?

Answer 24

Radionuclide bone scan

Question 25

What are some causes of osteoblastic bone metastases?

Answer 25

Prostate carcinoma Breast carcinoma Lymphoma Carcinoid tumors (rare)

Question 26

What are some causes of osteolytic bone metastases?

Answer 26

Lung Cancer (men) Breast Cancer (women) Renal Cell carcinoma Thyroid Carcinoma

Question 27

What are insufficiency fractures?

Answer 27

Type of Pathologic fracture in which mechanically weakened bone fractures as result of a normal or physiologic stress

Question 28

What are insufficiency fractures most common secondary to?

Answer 28

Osteoporosis in postmenopausal women

Question 29

What are common sites of insufficiency fractures?

Answer 29

``` Pelvis Thoracic Spine Sacrum Tibia Calcaneus ```

Question 30

How to insufficiency fractures appear on Xray?

Answer 30

They have a sclerotic band representing healing

Question 31

What studies are most sensitive to detecting insufficiency fractures?

Answer 31

CT MRI NMT

Question 32

What do bones consist of?

Answer 32

Cortex = compact bone | Medullary cavity = cancellous bone

Question 33

What is cancellous bone arranged as?

Answer 33

Trabeculae Blood vessels Hematopoietic cells Fat

Question 34

Where is the cortex best seen on X-rays?

Answer 34

In tangent

Question 35

What is MRI particularly sensitive to?

Answer 35

Assessment of bone marrow

Question 36

What tests are superior to X-rays for evaluation of soft tissues?

Answer 36

MRI and CT

Question 37

What does increased osteoblastic activity produce?

Answer 37

Focal or generalized decreases in bone density

Question 38

What does increased osteoblastic activity produce?

Answer 38

Focal or diffuse increased bone density

Question 39

What are the hallmarks of Paget Disease?

Answer 39

Thickening of the cortex Accentuation of the trabecular pattern Enlargement and increased density of the affected bone

Question 40

What is plasmacytomas and what can they produce?

Answer 40

Precursors to multiple myeloma/most common primary tumor of bone Produce focal areas of decreased bone density

Question 41

What do osteolytic metastatses produce?

Answer 41

Focal areas of decreased bone density

Question 42

What is osteoporosis characterized by?

Answer 42

Low bone mineral density Predisposes persons to Pathologic fractures

Question 43

What percentage of bone must be reduced in order to tell the difference in density on X-rays?

Answer 43

50%

Question 44

What test is most sensitive to presence of medullary metastatic disease?

Answer 44

MRI