Bone imaging lecture By Dr. Firas Abdullah
I) Radiological techniques used in bony imaging:لا تنسى قراءة الصور في المحاضرة الالكترونية
Plain X ray
Ultrasonography
CT scan
MRI
Radionuclide bone scanning
The signs of bone disease on plain X ray
(1) Decrease in bone density, which may be focal or generalized. Focal reduction in density is usually referred to as a ‘lytic area’ or an area of ‘bone destruction’. When generalized, decrease in bone density is best referred to as ‘osteopenia’
(2)Increase in bone density (sclerosis), which may also be focal or generalized.
(3) Periosteal reaction. The periosteum is not normally visible on a radiograph. The term ‘periosteal reaction’ refers to excess bone produced by the periosteum, which occurs in response to such conditions as neoplasm, inflammation or trauma.
The signs of bone disease on plain X ray
(1) Alteration in trabecular pattern is a complex response usually involving a reduction in the number of trabeculae with an alteration in the remaining trabeculae, e.g. in osteoporosis and Paget’s disease(2)Alteration in the shape of a bone is another complex response with many causes. (3)Alteration in bone age. The time of appearance of the various epiphyseal centers and their time of fusion depends on the age of the child.
Ultrasonography:
Ultrasound cannot demonstrate bone pathology
Detecting tenosynovitis, tendon tears and rupture
Diagnosis of DDH in infants.
Diagnosis of osteomyelitis.
Soft tissue lesions or calcification
Computed tomography
@ Demonstrating abnormalities in the spine, pelvis and Hips. Three-dimensional reconstructions can be made
@ Demonstrating the extent and characterization of bone lesion As a guide for bone biopsy.
❖Advantages: ❖Disadvantages:
Magnetic resonance imaging
Calcified tissues such as bone produce no signal with MRI, but MRI can demonstrate the bone marrow directly.
The major indications for musculoskeletal MRI are:
To demonstrate disc herniation and spinal cord or nerve root compression
To diagnose bone metastases
To show the extent of primary bone tumors
To image soft tissue masses
To diagnose osteomyelitis and show any soft tissue abscess
To diagnose avascular necrosis and other joint pathologies and to image both acute and chronic injury to joint cartilages, ligaments and other intra-articular soft tissues
Radionuclide bone scanning
Using Technetium-99m (99mTc)-labelled phosphate complexes given as an intravenous injection. They are taken up selectively by the bones and excreted in the urine.
Indications for radionuclide bone scanning are:
Detection of metastases
Detection of osteomyelitis.
Determination of whether a lesion is solitary or multifocal
Investigation of a clinically suspected bone lesion despite a normal
radiograph osteomyelitis Determination, in equivocal cases, of whether an abnormality seen on the radiograph is significant or not
Investigation of painful joint prostheses.
II) Bone pathology:
Solitary lytic or sclerotic lesions
Multiple focal lesions, i.e. several discrete lytic or sclerotic lesions in one or more bones
Generalized increase or decrease in bone density
Alteration of the trabecular pattern or change its shape.
Solitary bone lesion
➢ Lytic
➢ Sclerotic
➢ Mixed
o bone tumors (a) malignant (primary or secondary) (b) benign
o osteomyelitis
o bone cysts, fibrous dysplasia or other non-neoplastic defects of bone
o conditions of uncertain nature such as Langerhans histiocytosis and osteoid osteoma
How to determine the nature of the lesion?
1.Age of the patient
2.Site of the lesion
3.Zone of transition
4.The adjacent cortex
5.Expansion
6. Periosteal reaction
7.Calcific densities within the lesion
8.Soft tissue swelling
Zone of transition
❖ A lesion with a well-defined sclerotic edge is almost certainly benign, e.g. a fibrous cortical defect or a bone island
❖ A lytic area with an ill-defined edge is likely to be aggressive. E.g. malignant tumor and infection
❖ A lytic area with no sclerotic rim, which may be a benign or malignant lesion. E.g. metastases and myeloma
The adjacent cortex
Any destruction of the adjacent cortex indicates an aggressive lesion such as a malignant tumor or osteomyelitis.
Expansion
Bone expansion with an intact well-formed cortex usually indicates a slow-growing lesion such as an enchondroma or fibrous dysplasia
Periosteal reaction
The causes of localized periosteal reactions adjacent to a lytic or sclerotic lesion are:
❖ Osteomyelitis
❖ Trauma
❖ Malignant bone tumor, particularly Ewing’s sarcoma and osteosarcoma
❖ occasionally metastasis, particularly neuroblastoma
❖ Langerhans histiocytosis.
Calcific densities
within the lesion Calcification within an area of bone destruction occurs in specific conditions; for example, patchy calcification of a popcorn type usually indicates a cartilage tumor, whereas diffuse ill-defined calcification suggests osteoid formation and indicates an osteosarcoma
Soft tissue swelling
The presence of a soft tissue mass suggests an aggressive lesion .