Lecture 2: Principles of Radiographic Investigation Flashcards
What are these parts of the bone?
E: Epiphysis: The end of the growing bone is known as the epiphysis. Initially comprised of cartilage there is gradual ossification that eventually fused with the shaft (diaphysis) of the bone.
P: Physis: Cartilage growth plate bw epiphysis and metaphysis is known as the physis. Also referred to as the epiphyseal growth plate.
Z: Zone of provisional calcification: At the junction of the physis and the metaphysis a thin line of increased density is identifiable. Represents area of calcification of the physis cartilage and is the precursor to bone formation.
M: Metaphysis: Between zone of provisional calcification and the diaphysis. Most metabolically active area of bone and as such often area for tumors and infection. In this area calcified cartilage is transformed into definitive weight bearing stress trabeculae. Once weight bearing the width becomes greater than the diaphysis.
D: Diaphysis: Lies between both metaphysis and is longest part of bone. Also known as the shaft, Note a thickened cortex (out part of bone) and decreased medullary space.
Analysis of a bone lesion:
Position within bone
Site of Origin
Shape
Size
Margination (Zone of transition)
Cortical integrity
Medullary response
Periosteal Response
Lesions / Symmetry
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What is the position of this lesion?
Diaphyseal
What is the position of this lesion?
Apohyseal/apohysis
What is the position of this lesion?
Epiphyseal
What is the position of this lesion?
Epiphyseal-metaphyseal
What is the position of this lesion?
Metaphyseal
What are the different positions within bone a lesion can appear?
Apophysis: (analogous to epiphysis but site of muscular attachments) (in this case we see a chondroblastoma, an osteolytic(dark) lesion in the greater tuberosity of an 11 year old).
Epiphyseal Lesion: (well defined osteolytic lesion evident is distal tibial epiphysis of 7 yr. old, also chondroblastoma)
Epiphyseal - Metaphyseal lesion: (within lateral tibial epiphysis and metaphysis a sharply circumscribed abnormality is present: giant cell tumour)
Metaphyseal lesion: (An expansile osteolytic lesion occurs: aneurysmal bone cyst. Epiphysis is spared in this neoplasm)
Diaphyseal lesion: (Multiple sharply demarcated osteolytic lesions present throughout the diaphysis. Mote inner cortical destruction indicating medullary origin. A multiple myeloma).
What are these sights of origin?
A and B: Medullary: Note central location, slight expansion, thinned but intact cortex. Diagnosis simple bone cyst.
C and D: Cortical: Note eccentric location, cortical destruction and periosteal new bone formation. Diagnosis Ewing’s sarcoma.
E and F: Periosteal: A dense soft tissue mass is dominant feature, with no evidence of bone destruction. Observe the thin separating, radiolucent cleft between the mass and cortex (arrows) indicating its extra cortical origin. Diagnosis periosteal Osteosarcoma.
G and H: Extraosseous: Well demarcated soft tissue lesion visible demonstrates cortical and trabeculae bone properties. Diagnosis traumatic myositis ossificans.
Define imperceptible margins
Other terms used include poor, hazy or ill-defined margins, or a wide zone of transition. The gradation between the lesion and normal bone occurs gradually with no distinct demarcating line or change in density. This type of boundary is indicative of aggressive bone destruction as seen in infections and malignant tumours.
Define sharp margins
Synonyms include definite and sclerotic margins or a narrow zone of transition. The interface between the lesion and normal bone is clearly define and may be outlines by a sclerotic line.
Describe this lesions zone of transition
Moth eaten osteolytic lesion present in medullary cavity. Difficult to perceive where the lesion begins and ends which is typical of aggressive abnormality (Ewing’s sarcoma in this case).
Describe this lesions zone of transition
Sharp Margination. This geographic lesion exhibits a conspicuous zone of transition accentuated by the sclerotic margins. Denotes a contained, slowly growing lesion (fibrous dysplasia).
Describe this cortex
Thinning: There is extreme thinning of all visible cortices (pencil thin) and generalized demineralization of all bones present. Commonly seen in osteoporosis
Describe this cortex
Thickening: The two cortices are grossly thickened, with compromise of the adjacent medullary space. Additionally bone is deformed and has transverse lucencies on its convex surface (pseudo fractures), all consistent with diagnosis of Paget’s disease.
Describe this cortex
Expansion: Note the thin bulging but intact cortex of the proximal fibula. This represents continued endosteal erosion and periosteal deposition, with continued growth of the lesion. Diagnosis Aneurysmal bone cyst.
Describe this cortex
Destruction: Disruption of the cortex is indicative of an aggressive bone lesion; in this case from metastatic carcinoma.
Describe this cortex
Fracture: An oblique fracture line and disruption of the cortex is readily identifiable through a malignant lesion.
Describe this medullary response
Geographic: other terms are well circumscribed and uniformly lytic lesions. Usually solitary, > 1 cm and a sharper margin. In general are slower growing lesions, i.e. Least aggressive with narrow zone of transition.
Describe this medullary response
Moth Eaten: Multiple poorly marginated small or moderately sized lucencies are characteristic of this pattern. Frequently the margins of each lesion are ragged and irregular. This type of destruction reflects an aggressive abnormality with intermediate zone of transition.
Describe this medullary response
Permeative: Numerous tiny, pin hole sized lucencies (less than 1mm) constitute a permeative pattern. A wide zone of transition is evident. These lesions frequently overlooked because of their size, and with progression may enlarge enough to become moth eaten in character. Usually seen in the most rapidly aggressive malignant bone tumours.
What is this type of periosteal response?
Spiculated: Additional Terms include brushed whiskers and hair on end. The term SUNBURST has been used to describe radiating spicules of bone from a point source. Each spicule is separated from the other by an interposed radiolucent region. This pattern is indicative of a very aggressive bone tumour, often Osteosarcoma
Radiating spicules of bone (arrows) characterise this aggressive Osteosarcoma.
What is this type of periosteal response?
Solid: Defined by continuous layer of new bone that attaches to outer cortical surface. Typically related to a very slow form of irritation. Disorders include stress fractures, osteoid osteoma, venous stasis and hypertrophy osteoarthropathy.
What is this type of periosteal response?
Laminated: Also referred to as onion skinned. Most conspicuous feature is alternating layers of lucent and opaque densities on the external bone surface. At times only a single lamination will be visible. With time a laminated response may transform into a larger solid appearance. The significance of laminated response is varied, since it can be seen in slow and aggressive tumours as well as infections. Classic associated disorder is Ewing’s sarcoma.
What is this type of periosteal response?
Sunburst Periosteal Response: Periosteal spicules appear to radiate away from a point source. Diagnosis Osteosarcoma
What is this type of periosteal response?
Codman’s Triangle: A triangular shaped periosteal new bone formation typifies this named response (arrows) and is a significant but nonspecific finding in many disorders including infection, neoplasm and trauma.
What is this type of epiphyseal fracture?
Salter Harris type 1:
Represents isolated fracture through the growth plate. Usually the radiograph appears normal, with the diagnosis being made clinically because of tenderness over the epiphyseal plate and soft tissue swelling.
What is this type of epiphyseal fracture?
Salter Harris type 2:
This is a fracture through the displaced growth plate, which carries with it a corner of the metaphysis. The metaphyseal fragment has been called the Thurston Holland sign. Most common epiphyseal injury, comprising approximately 75% of cases. The most common sites are the distal radius (50%), as well as the tibia, fibula, femur and ulna. The epiphyseal separation is usually easily reduced and a good prognosis is the outcome.
What is this type of epiphyseal fracture?
Salter Harris type 3:
The fracture line is directed along the growth plate and then turns towards the epiphysis. It results in intra-articular fracture that may require open reduction treatment. Most frequent site is the distal tibia.
What is this type of epiphyseal fracture?
Slater Harris type 4:
Obliquely orientated, vertical fracture that passes through the epiphysis, growth plate and metaphysis. The fracture fragment consists of a portion each of the metaphysis, growth plate and epiphysis. The most common sites are the lateral condyles of the distal humerus in patients under 10 yrs., and the distal tibia in those over 10.
What is this type of epiphyseal fracture?
Salter Harris type 5:
Least common and results from a compressive deformity of the growth plate. Initially, the radiographs are normal, until cessation of growth plate creates bone shortening or partial arrest, which leads to progressive angular deformity. Most common sites are distal tibial and distal femoral epiphyseal centres.
