approach to bone radiology

By Dr. Maysaloon Shaman F. I. B. M. S (Diag.Rad.)

X-ray Isotope US CT MRI

Plain bone radiograph

Initially, a musculoskeletal lesion should be simply imaged with a plain film. It should be remembered that plain films remain the most reliable imaging method for assessment of both biologic activity and probable histological diagnosis of an osseous lesion.

Signs of bone disease in plain X-ray

1-Decreased bone density 2-Increased bone density (sclerosis). 3- Periosteal reaction 4- Cortical thickening 5- Alteration in the trabecular pattern 6- Alteration in the shape of a bone 7-Altreration in bone age 8- Alteration in its alignment with joints.

Localize (lytic area or area of ‘ bone destruction)Generalize

Giant cell tumor

osteoporosis

2-increased bone density (sclerosis) Focal Generalized

Osteopetrosis

osteosarcoma

It refers to excessive bone produced by the periosteum, which occur in response to infection , trauma & tumors

Patterns of periosteal reaction

lamellar
Onion Peel

Hair on end

Codman’s triangle

Linear

Also involve laying down of new bone by the periosteum,but the process is very slow & it has the same homogeneous density as does the normal cortex & there is no separate lines or spicules of calcification as seen in a periosteal reaction

causes of cortical thickening : 1- chronic osteomylitis. 2-healed trauma 3- response to chronic stress or benign tumor

Chronic osteomylitis

Usually involving a reduction in the no. of trabeculae with an alteration in the remaining trabeculae.e.g in osteoporosis, there is reduction in the no. of the trabeculae & remaining trabiculae are more prominent than usual associated with thinning of the cortex. in paget‘s disease , there is thickening of the trabeculae & associated with thickening of the cortex & bone expansion

Paget disease

Congenital Acquired , e.g Acromegaly, expanding bone tumors , metabolic bone diseases, trauma .

Fracture

Paget's disease

Soap bubble - GCT

Cumulus cloud - Osteosarcoma



US can not demonstrate bone pathology but does have a complementary imaging role; Detecting tenosynovitis, tendon tear & rupture. In diagnosis of osteomyelitis. In diagnosis of congenital hip dysplasia.

Technetium-99m lablled phosphate complexes

Detection of metastasis.Detection of oseomylitis .Determination of whether a lesion is solitary or multiple.Investigation of clinically suspected lesion when the Plain radiograph is –ve.Investigation of radiographically equivocal cases whether is significant or not.Investigation of painfull prosthesis .


Is only needed in selected cases. Indications for bone CT are Demonstrating abnormalities in the areas where plain films are frequently difficult to be interpretated for exam. Spine , hip &pelvis As a guide for bone biopsy. Demonstration of the extent &characterization of the bone tumor in selected cases to complement MRI

Play a vital important role in musculoskeletal disorders. In can demonstrate bone marrow directly but calcified tissues & cortical bones produces no signal. MRI particularly good for showing soft tissue abnormalities


Disc herniation & spinal cord or nerve root compression. Dx of bone metastasis. Extend of primary bone tumor. To image soft tissue masses To Dx osteomyelitis & shows any soft tissue abscess. To Dx avascular necrosis & other joint pathologies


Bone disease can be divided: 1- focal: lytic , sclerotic or mixed solitory multiple 2- generalized; where all the bones show diffuse increase or decease in bone density 3- alteration in the trabecular pattern or changes in the shape

Lytic Sclerotic Mixed

Radiological approach for diagnosis of solitary bone lesions to decide whether the lesion is benign (i.e. stable or very slow growing) or whether the lesion is aggressive (malignant tumor or infection).

1. Age of the patient. This can be an extremely important determinant in some lesions in which the age range of occurrence may be quite narrow. For example, Malignant osseous lesions in patients under one year of age are usually metastatic neuroblastoma. Malignant osseous lesions in the age range of 1 to 30 years are usually osteosarcoma or Ewing's sarcoma. Malignant osseous lesions in the 30- to 60-years range most commonly will be either chondrosarcoma, primary lymphoma, or malignant fibrous histiocytoma, Malignant lesions in the age range over 50 most commonly will be due to metastatic disease or multiple myeloma.

Three different types of locations should be noted: 1- the particular bone that is involved. ( long bone ,flat bone , small bones) 2- the location in a transverse axis. (central, eccentric, or a cortically-based epicenter). 3- the location in a longitudinal axis of a long bone. (epiphysis, metaphysis or diaphysis). Certain lesion occur at the certain sites; E.g. Osteomyelitis characteristically occur in the metaphyseal areas specially of the knee & lower tibia whereas giant cell tumor occur in subarticular areas

i.e. Zone of transition of the lesion from abnormal to normal bone; A wide zone of transition denotes an aggressive lesion. A narrow zone is a much less aggressive lesion. well defined sclerotic edge is almost certainly benign.

Diaphyseal

Metaphyseal
Epiphyseal
Chondroblastoma
Exostosis
Ewing’s sarcoma

Osteoid osteoma

Chronic osteomyelitis

Brodies abscess

Osteosarcoma


Any destruction of the adjacent cortex indicates an aggressive lesion such as a malignant tumor or osteomyelitis

Fracture

Osteomyelitis

Osteosarcoma

Bone expansion with an intact well formed cortex usually indicate a slow growing lesion such as an encondroma or fibrous dysplasia.

Fibrous dysplasia

Enchondroma

Presence of an active periosteal reaction in the absence of the trauma usually indicates an aggressive lesion

Osteosarcoma

Enchondroma

Cortical breakthrough of a bone lesion to create a soft tissue mass generally suggest an aggressive lesion(infection or tumor) . ill define soft tissue swelling adjacent to focal bone destruction lesion suggest infection . well define soft tissue swelling adjacent to the bone lesion suggest neoplasm& such soft tissue masses will often distort but not obliterate nearby muscle planes.

Common terminology includes ; "geographic" (well-defined or map-like lesion, the least aggressive pattern), "moth-eaten" (holes, with less well-defined margins, appearing more aggressive) "permeative" (a poorly demarcated pattern which is often very difficult to visualize and represents a highly aggressive lesion)


Geographic
Moth eaten

Anurysmal bone cyst

Unicameral bone cyst

allow categorization of a lesion as bone producing versus cartilage producing. Diffuse ill defined calcification within the lesion suggest osteoid lesion . presence of a patchy calcification of popcorn or stippled type with density more than normal bone usually indicate cartilagenous tumor

Enchondroma

Chronic abscess

Generally, a larger lesion (greater than 5 cm) is more likely to be malignant or aggressive, but there are many exceptions to this statement, and other determinants are generally more important than this one.

This is the last most important point , since polyostotic lesions automatically restrict the number of disease processes that might be considered. For example, nonaggressive polyostotic lesions should be confined to; fibrous dysplasia Paget's disease Histiocytosis multiple exostosis multiple enchondromatosis Aggressive polyostotic lesions would be confined to osseous metastases multiple myeloma primary bone tumor with osseous metastases, multifocal osteomyelitis, aggressive histiocytosis, and multifocal vascular bone tumors.

Eosinophilic granuloma

Multiple myeloma

Bony metastases

Bony metastases


Multiple lesions are seen in Multiple Myeloma, Metastasis, Fibrous dysplasia
Most of the primary bone tumors are solitary