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What is the systematic approach (ABCs) to reading radiographs?
- A: anatomic approach
- B: bone mineralization/quality
- C: cartilage
- S: soft tissue
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What are the 2 types of bone?
- Compact: dense outer layer/cortex
- Cancellous: less dense/medullary canal, arranged as trabeculae, separated primarily by blood vessels
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What is the appearance of bone cortex on conventional radiograph?
- smoothly contoured dense white shell
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What is the appearance of the medullary cavity of bone on conventional radiograph?
- grayish material inside the cortical shell, interlaced with a fine network of bony trabecular markings
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Relatively speaking, how many trabeculae are in the midshaft (diaphysis) vs the metaphysis or epiphysis of long bones?
Fewer (in midshaft)
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In conventional radiographs, what are the 2 views taken at 90 degree angles required for study, referred to as?
Orthogonal views
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How much of a reduction of bone is needed to produce a recognizable abnormality on conventional x-rays?
Approx. 40-50% bone loss
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Bones reflect the general _______ status of the individual.
metabolic
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What are the 4 mechanical forces that control bone density/metabolism?
- Osteoblastic activity
- Osteoclastic activity
- Production of normal osteoid matrix
- Mechanical stress
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What the two categories of bone abnormalities and the extent of disease?
- Abnormalities: increased bone density, decreased bone density
- Extent: focal, generalized (diffuse)
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Osteoblast/clast activity, metastatic disease (CA), hormonal changes/disease, genetics, vitamin D deficiency, renal disease, and fractures (AVN) all cause what?
Changes in bone density.
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Version of bone density that shows thickening of bone, either diffusely or locally, resulting in bright white appearance on x-ray.
Sclerotic Bone
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Version of bone density that shows loss of bone density, either diffusely or locally, resulting in darkening of bone on x-ray (lucency).
Lytic Bone
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What conditions cause generalized increased bone density (sclerotic bone)?
- Diffuse osteoblastic metastases
- Osteopetrosis
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What conditions cause the 3 types of focal increased bone density (sclerotic bone)?
- localized osteoblastic metastases (prostate CA)
- avascular necrosis (AVN)
- paget's disease
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What conditions cause generalized decreased bone density (lytic or lucent bone)?
- osteoporosis
- hyperparathyroidism
- rickets and osteomalacia
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What conditions cause focal decreased bone density (lytic or lucent bone)?
- localized osteolytic metastases
- multiple myeloma
- osteomyelitis
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What is a common cause for generalized increase in bone density (prototypical diffuse sclerotic bone disease), with diffuse bloodborne metastatic disease causing over-active osteoblastic activity?
- Carcinoma of the prostate (prostate cancer)
- **80% of pts with prostate CA have metastatic bone disease found on autopsy...multiple mets are more common than solitary**
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What is this radiograph an example of?
diffuse prostate cancer metastases
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Label the structures on this normal radiograph of the pelvis.
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How does a patient with metastatic prostate CA usually present?
- PMH of prostate (or breast) cancer
- usually c/o of back pain or pelvic bone pain
- may be asymptomatic
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Rare, hereditary bone defect caused by dysfunction of osteoclasts that involves the entire skeleton, producing weaker, brittle bones (pathologic fx's). Infantile form results in pancytopenia.
Osteopetrosis ("marble bone disease")
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What is this radiograph as example of?
- osteopetrosis ("marble bone disease")
- **remember infantile form results in pancytopenia**
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What is this radiograph an example of?
Osteopetrosis ("marble bone disease")
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What is this radiograph an example of?
osteopetrosis ("marble bone disease")
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How many different forms of osteopetrosis are there? Which is the most severe? What about the benign form?
- Five different forms of disease
- Infantile (most severe): blindness, deafness, facial paralysis (tx bone marrow transplant)
- Benign: dx later in life, several fx's, difficulty healing
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What areas of bone are affected by diseases causing focal increase in bone density? What is the appearance of these affected areas?
- Cortex: periosteal reaction (new bone in periosteum); AVN, metastatic CA
- Medullary cavity: punctate, amorphous sclerotic margins of the lesion, surrounded by normal appearing medullary cavity (medullary bone infarcts)
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What does localized CA on x-ray simulate? Where is localized CA metastases typically seen?
- Simulate increased osteoblastic activity
- Typically seen in vertebrae, ribs, pelvis, humeri and femur
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What is this radiograph an example of?
localized metastatic prostate CA
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What is the study of choice for detecting bone mets, regardless of suspected primary CA?
Bone Scan
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Balance between osteoblastic vs osteoclastic activity shows a region that appears more dense than surrounding bone on x-ray.
avascular necrosis (AKA aseptic necrosis, ischemic necrosis or osteonecrosis)
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What is this radiograph an example of?
avascular necrosis
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Where does AVN frequently occur?
- femoral head
- humeral head
- scaphoid (most common fx of carpal bones)
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What percentage of scaphoid fractures will develop AVN? Where on the scaphoid does AVN typically occur in particular after a fx?
- 10-30%
- Proximal pole of scaphoid
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What is the study of choice (gold standard) for diagnosing AVN? What is the usual order of radiographic studies performed to dx AVN?
- MRI (study of choice)
- Order: 1st-plain radiograph, 2nd-bone scan, 3rd-MRI scan
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What is this radiograph an example of?
AVN of the scaphoid
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What is this radiograph an example of?
Fx of the waist of the scaphoid & appearance of increased density of the proximal pole of the scaphoid (AVN).
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Where are medullary bone infarcts typically found?
Metadiaphysis of long bones
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What is this radiograph an example of?
AVN of the femoral head (notice crescent sign-linear subcortical lucency in red circle)
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What is this radiograph an example of?
AVN of the femoral head (notice the crescent sign)
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Dense, serpiginous collections of bone within the medullary cavity frequently surrounded by a thin, sclerotic membrane. Usually asymptomatic, so symptomatic pts should be evaluated further.
Medullary bone infarcts
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What is this radiograph an example of?
Medullary bone infarct (femur, tibia)
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What is this radiograph an example of?
medullary bone infarct (femur)
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What is this radiograph an example of?
medullary infarct (humerus)
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Chronic bone disease caused by chronic paramyxoviral infx that typically occurs in males (rarely before age 40).
Paget's disease
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What is this radiograph an example of?
paget's disease (femur)
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What is the significance of this radiograph in someone with Paget's disease?
Increased size of the calvarium (skull cap), increased hat size.
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What is the presentation of patients with Paget's disease?
- varying degrees of increased bone formation (L-spine, T-spine, proximal femur and calvarium)
- mechanically inferior (long bones)
- pathological fx's
- bowing (long bones)
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Focal thickening of the cortex, accentuation of trabecular pattern (different from prostate CA), increase in size of bone involved (gradual increase in man's hat size) on radiograph describe what?
Imaging HALLMARKS of Paget's disease
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What are the examples shown in the radiograph?
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What is this radiograph an example of?
paget's disease (different than diffuse prostate CA mets)
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What is this radiograph an example of?
paget's of femur with fracture
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Low bone mineral density, generally divided into two types, can be caused by long term corticosteroids, Cushing's disease, estrogen deficiency, alcoholism, inadequate physical activity.
Osteoporosis
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What are the two types of osteoporosis?
- postmenopausal (osteoclast activity)
- age related loss of total bone mass (starts at 45-55 yo)
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What is the most accurate scan for bone mineral density measurement?
DEXA (dual energy x-ray absorptiometry)
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What is this radiograph an example of?
osteoporosis (spine)
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What are the 3 forms of hyperparathyroidism?
- Primary: usually caused by single adenoma (80-90%) w/ hypercalcemia
- Secondary: hyperplasia of glands due to imbalance of Ca and phosphorous caused by chronic renal disease
- Tertiary: develops from long standing secondary hyperparathyroidism, leads to hypercalcemia
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Diffuse decrease in bone density, subperiosteal bone reabsorption, usually found on radial side of middle phalanges of index and middle fingers, erosion of distal clavicles, well circumscribed lytic lesions in long bones (brown tumors), and salt and pepper appearance of skull on plain x-ray are indicative of what condition?
hyperparathyroidism
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What is this radiograph an example of?
subperiosteal bone resorption (hyperparathyroidism)
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What is this radiograph an example of?
erosion of distal clavicle (hyperparathyroidism)
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What is this radiograph an example of?
brown tumors in femur (hyperparathyroidism)
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Fraying and cupping at the metaphyses of long bones, widening and irregularity of epiphyseal plates and soft pliable bones are all indicative of what condition?
Rickets (childhood vit D deficiency)
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What is this radiograph an example of?
rickets (cupping & fraying at metaphyses of femur, tibia and fibula)
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What is this radiograph an example of?
rickets (wrist showing cupping & fraying at metaphyses of distal radius and ulna)
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What is this radiograph an example of?
rickets
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What is this radiograph an example of?
fraying and cupping of metaphysis (rickets)
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What is this radiograph an example of?
rachitic rosary (rickets)
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Failure of bone matrix to calcify in adults, most commonly caused by chronic renal disease.
osteomalacia
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Diffuse decreased bone density, thinning cortex, and coarsening of the trabecular pattern are x-ray findings for what condition?
osteomalacia
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What is this radiograph an example of?
osteomalacia (adult rickets), notice the "looser line" or pseudo fracture (black arrow)
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What is this *hallmark sign* of osteomalacia?
"looser line", pseudofractures
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These occur at multiple sites, are short and lucent bands at Rt angles to the cortex, have sclerotic margins in later stages, are frequently bilateral and symmetrical, and are associated with nonunion of healing fractures.
"looser line" pseudo fractures (osteomalacia)
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What most commonly produces focal decrease in bone density?
Focal infiltration of cells other than osteocytes (in lytic metastatic disease, malignant cells replace normal bone cells).
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The medullary cavity is almost always involved with what condition that progresses and may erode and destroy the cortex as well.
Osteolytic metastatic disease (if cortex only is involved, its much easier to visualize)
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Irregularly shaped, lucent bone lesions in single or multiple places characterized by one of three patterns are classic findings of what disease? What are the patterns?
- Osteolytic metastatic disease
- Geographic, mottled, permeative
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Which pattern of osteolytic metastic disease is this?
- Geographic
- It is the most visible lesion, involving complete destruction of cortex bone.
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Which pattern of osteolytic metastatic disease is this?
- Mottled
- Ill-defined lytic lesions with limited area of destruction, may involve small portion of the cortex, and is typically described as "moth-eaten".
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Which pattern of osteolytic metastatic disease is this?
- Permeative
- May be very discrete, not easily seen, limited to a small area with little destruction of bone.
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What is this radiograph an example of? What type of carcinomas in particular cause this type of lesion?
- Osteolytic metastatic disease with expansile, soap bubble appearance.
- Especially seen in pts with renal and thyroid carcinomas.
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What is this radiograph an example of? How can this be a useful diagnostic tool?
- Pedicle sign
- MAY help differentiate metastases from EARLY multiple myeloma which spares the pedicles.
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The most common primary bone malignancy in adults (most dx after 65 yo, rare under 35 yo), develops in bone marrow causing anemia, bleeding problems, bone or back pain, commonly seen in spine and pelvis.
Multiple Myeloma
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MRIs are more sensitive than plain x-rays, and conventional radiographs are more sensitive than bone scans for what condition?
Multiple Myeloma
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What is the most common early manifestation on conventional radiographs that indicate multiple myeloma?
Diffuse, usually severe osteoporosis.
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What form of multiple myeloma does this radiograph show?
- Solitary form (plasmacytoma) indicating early onset of disease.
- Shows an expansile, soap bubble appearing lesion in the long bones, spine or pelvis.
- May also show soft tissue masses.
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What is this radiograph an example of?
plasmacytoma of humerus (multiple myeloma)
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What form of multiple myeloma does this radiograph show?
- Disseminated (later stages), showing multiple, small, sharply circumscribed, "punched out" lytic lesions.
- Lesions are typically found through out axial and proximal extremities (roughly all the same size).
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What is this radiograph an example of?
multiple myeloma found in legs
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What is this radiograph an example of?
multiple myeloma of the pelvis
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Focal destruction of bone, typically due to infection (commonly S. aureus). In children it typically occurs at the metaphysis-exuberant blood supply. In adults, infections tend to involve joint space.
- Osteomyelitis
- **adults get both osteomyelitis and septic arthritis**
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Focal cortical bone destruction, new periosteal bone formation, soft tissue swelling, focal osteoporosis from hyperemia are all common x-ray findings for what condition?
- Osteomyelitis
- Can take up to 10 days for osteomyelitis to show on plain x-rays (MRI, nuc med scans typically used to confirm dx).
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What is this radiograph an example of?
osteomyelitis of the 2nd metatarsal
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What is this radiograph an example of?
femoral osteomyelitis
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What is this radiograph an example of?
osteomyelitis of tibia
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What is this radiograph an example of?
septic arthritis of the elbow (osteomyelitis)
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