Imaging of bone diseases

Imaging of bone diseases Qais A. Altimimy, DMRD, CABMS-RAD. Lecturer, Radiology Alkindy college of medicine, university of Baghdad 2015

Imaging of bone disease 1- Plain x-ray 2- Radio isotope 3- CT scan 4- MRI

Signs of bone disease on plain x-ray 1-bone density decreased or increased(sclerosis) 2-periosteal reaction 3-cortical thickening 4-alteration in trabecular pattern 5-alteration in the shape of bone


Role of US in imaging of musculoskeletal diseases US can not demonstrate bone pathology , but does have a complementary imaging role in: 1.Detecting tenosynovitis, tendons tear and rupture 2.Diagnosis of osteomyelitis

Indications of Radioisotope bone scanning(TC-99m labelled phosphate complex)

1-detecion of metastasis 2-detection of osteomyelitis 3-to decide if an abnormality on radiograph not seen 4-investigation of painful prosthesis

Indications of CT scan in bone diseases

1- imaging of complex shaped bone difficult to be interpreted by x ray film e.g. pelvis, hip and spine 2- demonstration of extension & characterization of selected bone tumors complementary to MRI 3. as a guide for bone biopsy

Role of MRI in musculoskeletal diseases

MRI play a vital important role in MSK disorders It can demonstrate bone marrow directly, but calcified tissues and cortical bones produce no signal MRI particularly good for showing soft tissue abnormalities


Indications of MRI include: 1.disc herniation, spinal cord/nerve root compression 2.diagnosis of bone metastases 3.demonstartion of extension of primary bone tumor 4.to image soft tissue masses 5.to diagnose osteomyelitis, show any soft tissue abscess 6.to diagnose avascular necrosis & other joint pathologies

Radiological approach for diagnosis of solitary bone lesions: To decide whether the lesion is benign or aggressive (malignant tumor or infection) 1. Age of the patient: 0-10 yrs Ewing sarcoma 10-30 yrs Osteogenic sarcoma 20-40 yrs Reticulum cell sarcoma ,Fibrosarcoma 40-50 yrs Chondrosarcoma , Paraosteal sarcoma 60-70 yrs Metastasis 2.Which bone is involved: Flat , small or long bone Centric, eccentric or cortically based location Epiphyses, metaphyses or diaphyses

3.Pattern of bone destruction:

Geographic pattern: well defined, map like lesion

Mouth eaten pattern: holes with less well defined margins,

Permeative pattern: ill defined elongated holes very difficult to visualize

NOF
Multiple myeloma
Leukemia
Less malignant
More malignant


4.zone of transition: a lesion with a well defined edge is almost certainly benign , whereas a lytic area with an ill-defined edge is likely to be aggressive(include both tumor and infection).

5.Adjacent cortex: any destruction of the adjacent cortex indicate aggressive lesion

Solid
Lamellated
Codman’s Sunburst
Less malignant
More malignant
6.Periosteal reaction: Excess bone produced by the periosteum which occurs in response to such condition: a-neoplasm b-inflammation c-trauma


7. Expansion: bone expansion with an intact well formed cortex usually indicate a slow growing lesion

8. Soft tissue involvement: Well defined soft tissue swelling distorting muscle fatty planes= neoplasm Ill defined soft tissue swelling obliterating muscle fatty planes= infection
NOF
Enchodroma
Fibrous dysplasia


9.Calcified densities within the lesion(tumor matrix): Diffuse ill defined, fluffy, cotton or cloud-like calcification = osteoid forming tumor Patchy calcification of annular, popcorn or stippled= cartilagenous forming tumor 10. Size of the lesion: If the lesion > 5 cm, it is more likely to be aggressive lesion, but there are many exception 11.Polyostotic versus monostotic: Polyostotic lesions automatically restrict the number of the disease processes that may be considered in the differential diagnosis
chondrosarcoma


Radiological features of benign bone tumor : Plain x ray: 1. Well defined sclerotic margins 2. Narrow zone of transition 3. Expansion, but rarely produce cortical breakdown 4. There is no soft tissue mass 5. Periosteal reaction is unusual unless there is associated fracture and it is mainly of solid type Isotop scan: little or no increase in activity unless there is associated fracture CT and MRI: Rarely needed in their evaluation


Radiological features of malignant bone tumor :

Plain x ray: 1. Poorly defined margins 2. Wide zone of transition 3. Cortical destruction 4. Soft tissue mass may be seen 5. Periosteal reaction is often present and it is mainly of sunburst or Codman triangles types Isotop scan: Increased activity CT and MRI: Usually needed in their evaluation for further characterization and demonstration of soft tissue extension

Benign vs. Malignant

Osteomyelitis Usually occur in children and infants Initial radiographic appearance is normal and bone changes are not visible until 10-14 days of the infection Most sensitive imaging modalities are isotope scan and MRI which may show the disease within 1-2 days

Acute osteomyelitis: Typically affect the metaphysis of the long bones X-ray findings: 1.Soft tissue swelling with characteristic obliteration of fat planes is the earliest sign which may be evident within first 2 days 2.Local osteoporosis may be seen within 10-14 days 3.Bone destruction in the metaphysis with periosteal reaction that eventually may become very extensive & surround the bone to form involucrum which is usually visualized after 3 weeks 4.Part from the original bone may die and separate to form dense fragment called sequestrum Isotop scan: Increased activity in both early and delayed phase MRI: Is the investigation of choice and may show evidence of bone edema and pus accumulation in the bone and soft tissue

Chronic osteomyelitis Osteomyelitis of Garre The bone become thickened & loss differentiation between the cortex & medulla= chronic nonpurulent process
Brodie abscess

osteomyelitis of Garre

Cortical thickening Laying down of new bone, there is no separated lines or spicules of calcification as seen in periosteal reaction Causes: 1- chronic osteomyelitis 2- healed trauma 3- response to chronic steroid 4- benign neoplasm


Multiple focal bone lesions Metastases and multiple myeloma are the commonest causes Metastases: Is the commonest malignant bone tumor Those bones which contain red marrow are the commonest sites to be affected namely spine, skull, ribs, pelvis, humeri and femora Lytic metastases: most commonly from carcinoma of breast, bronchus, thyroid , renal and colon. Radiologically appear as well defined or ill defined areas of bone destruction without sclerotic rim Sclerotic metastases: most commonly from carcinoma of prostate(men), and breast(women). Radiologically appear as ill defined areas of increased density of varying sizes Mixed metastases: commonly from carcinoma of breast


Bone expansion is uncommon in metastases except in renal and thyroid Periosteal reaction is uncommon Isotope scan is more sensitive than plain film in detecting metastases and if multiple areas of increased activity are seen in patient with known primary carcinoma, then the diagnosis of metastases is virtually certain MRI is better than isotope scan for detecting & it show more metastases but it is more difficult to survey the whole skeleton with MRI CT is less sensitive than MRI for detecting metastases, but can demonstrate lytic sclerotic metastases & the images should be reviewed on bone windows

Rain drop skull

Punched out luciencies

Osteopenia Compression fracture

Generalized decreased bone density (osteopenia) Main causes: 1. Osteoporosis 2. Osteomalacia 3. Hyperparathyroidism 4. Multiple myeloma

Disorder

Specific radiographic clues
osteomalacia
Looser zones
hyperparathyroidism
subperiosteal resorption
disseminated multiple myeloma
focal lytic lesions



Osteoporosis
Due to deficiency of the protein matrix(osteoid) Matrix reduced in quantity. But the remaining bone is normally mineralized Causes: 1-idiopathic: juvenile, senile, postmenopausal 2-cushing syndrome and steroid therapy 3-disuse

Radiological features of osteoporosis 1. Changes in bone density usually is unapparent until 30-50% of bone mass has been lost. The changes are best seen in the spine 2. Decreased cortical thickness 3. Decreased number of trabeculae present in the bone due to resorption of horizontal trabeculae 4. Empty box appearance of vertebra; apparent increased end plate density due to resorption of spongy bone 5. Vertebral body compression fracture; wedged or biconcave types with apparent widening of disc spaces

Rickets & osteomalacia

Lack of calcium in the body tissue with poor mineralization of osteoid . If this occurs before epiphyseal closure it is called rickets while in adults it is called osteomalacia Radiological findings in osteomalacia: 1. Decreased bone density(osteopenia) 2. Looser zones: are short lucent bands running through cortex at the right angles& may have sclerotic margins. Commonest sites are scapula, medial aspect of femur, pubic rami and ribs 3. Bone deformity due to bone softening e.g. biconcave vertebral bodies

looser zone

A child with rickets, demonstrating classic metaphyseal fraying and physeal widening
Rachitic rosary


Hyperparathyroidism Primary : due to parathyroid adenoma in 90 % Secondary: due to renal dysfunction Hyperparathyrodism cause mobilization of calcium from the bone resulting in decreased bone density Many patient with primary type presented with renal stones & dyspepsia Radiological findings include: 1. Generalized decrease in bone density (osteopenia) 2. The hallmark is subperiosteal bone resorption 3. Spotty deossification of skull (salt & pepper appearance ) 4. Soft tissue and vascular calcification& sometimes chondrocalcification 5. Regional osteosclerosis especially of spine( Rugger jersey spine) 6. Brown tumors are occasionally present which are small lytic lesions either single or multiple

Salt and Pepper Skull

Generalized increased bone density a-osteopetrosis b-myelosclerosis c-sclerotic metastasis d-Pagets disease
Osteopetrosis



Alteration in the trabecular pattern Reduction in number of trabeculae and alteration in the remaining ones a-osteoporosis: thick cortex, long trabeculae b-Pagets disease: thick trabeculation in cortex and medulla c-haemolytic anemia: biconcave bone marrow

hair-on-end" appearance

H-shaped" vertebrae
Expanded ribs Paravertebral masses


Alteration in the shape of the bone a-achondoplasia b-multiple exostosis c-acromegaly d-expanding bone tumour


Diaphyseal aclasia ( multiple exostosis): Is a congenital disorders There are multiple bony projections known as osteochondromas or exostosis They have cartilaginous cap which may contain calcifications Exostosis occur in metaphysis and directed away from the joint

Thanks for attention