INTRODUCTION TO SKELETAL IMAGING

Muhammad Bin ZulfiqarPGR II SIMS/SHL

New Radiology Department

Overview of Skeletal system•Total bones 206•Skull bones 22 •Ear bones 6 •Throat Bone 1 •Thorax 25•Vertebral column 24•Shoulder girdle 4 •Upper limb 60•Pelvis 4

•Lower Limb 60

Imaging Modalities for Skeletal System •Plain Radiographs(main focus)•Nuclear Scintigraphy•Contrast Examination•Ultrasound•Computed Tomography•Magnetic Resonance Imaging

Major Diseases of Bone

Trauma Congenital Infections Tumors Metabolic, Endocrine, Nutritional Bone Dysplasia Inflammatory Diseases(R.A.) Associated soft tissues abnormalities

Skeletal Anatomy and Physiology

Skeletal Development Intramembranous Ossification Enchondral Ossification

Bone Structure Epiphysis – ZPC – Metaphysis

– Diaphysis Cortex – Medulla – Periosteum

– Endosteum

Bone Metabolism Bone mineral - Hormones

Anatomy

Anatomy

Anatomy

Approach to skeletal imaging

Preliminary Analysis

• Clinical data

• Number of lesions

• Symmetry of lesions

• Determination of Systems Involved

Analysis of The Lesions

Skeletal Location

Position Within Bone

Site of Origin

Shape

Size

Margination

Cortical Integrity

Analysis of The Lesions

Behavior of Lesions• Osteolytic Lesions• Osteoblastic Lesions• Mixed Lesions

Matrix Periosteal Response• Solid Response• Laminated Response• Spiculated Response• Codmans’ Triangle

Radiologic Predictor Variables Supplementary Analysis

Other imaging Procedures Laboratory Examination Biopsy

Soft Tissue Changes

TRAUMA

Fracture and Dislocation

The radiographs should be made Include at least one joint Preferably two joints Two position AP – LAT

TRAUMA

Time intervals between Radiographic Study Initial Diagnostic study Post reduction and post immobilization One or Two weeks later, if position has

changed After approximately six eight weeks for

Primary callus After each plaster cast or traction change Before final discharge of patient

TRAUMATypes of Fracture Closed fracture

Does not break the skin or communicate

with the outside environment Simple fracture

Open fractur Penetrates the skin over fracture site Compound fracture

TRAUMA

Comminuted fracture Two or more bony fragments have separated

Non Comminuted fracture Penetrates completely through the bone

Avulsion fracture Tearing away of a portion of the bone

Impaction fracture Bone is driven into its adjacent segment

TRAUMA Incomplete Fracture

Broken only one side of the bone Greenstick (Hickory Stick) fracture Torus (Buckling) fracture

Fracture Orientation Oblique fracture

Commonly occurs in the shaft of long

tubular bone 45° to the long axis of the bone

Fractur

Fracture

TRAUMA

Spiral fracture Torsion, coupled with axial compression

and angulation Transverse fracture

Run at a right angle to the lonh axis Uncommon through healthy bone Pathologic fracture

Fracture

TRAUMA

Spatial Relationships of Fracture Alignment

Position of the distal fragment in relation

to the proximal fragment Apposition

Closeness of the bony contact at the

fracture site If the ends are pulled referred to as

Distraction

Fracture

TRAUMA

Rotation Twisting forces on a fractured bone along

its longitudinal axis

Traumatic Articular Lesions Subluxation Dislocation Diastasis

Epiphyseal Fractures Salter-Harris Classification

Salter - Harris

Dislocation

TRAUMAFracture Healing Main steps in fracture healing

Formation of hematoma Organization of hematoma Formation of fibrous callus Replacement of fibrous callus by

primary bany callus Absorption primary bany callus

Transformation to secondary bony callus Remodeling

TRAUMA

Complication of Fractures Immediate complication

Arterial injury Compartment syndrome Gas gangrene Fat embolism syndrome Thromboembolism

TRAUMA Intermediate complication

Osteomyelitis Myositis ossificans Synostosis Delayed union

Delayed complication Osteonecrosis Osteoporosis Non union – Mal union

Myositis Ossificans

INFECTION

Suppurative Osteomyelitis

General Consideration Systemic or Local infections Immunosuppresed patients, alcoholics,

newborns, and drug addicts are predisposed Antibiotics have significatly reduced the

sepsis-related mortality

INFECTION

Etiology Staphylococcus aureus causes 90% Pathway for the spread

Hematogenous Contiguous Direct Implantation Postoperative

INFECTION Radiologic Features

Bone scan are the earliest means of

diagnosis Radiographic latent period for plain film

10 days for extremities 21 days for spine

Soft tissue alteration : elevated fat planes,

obliterated fat planes, increased density.

INFECTION Bone changes :

Moth-eaten bone destruction

Usually metaphyseal in origin Periosteal new bone formation

Solid – Laminated – Codman’s Triangle Sequestrum Involucrum Joint space destruction (ankylosis)

0steomyelitis

Osteomyelitis

INFECTION

Septic Arthritis General consideration

Single joint involvement in the rule Most common route is hematogenous

or direct traumatic implantation Etiology

Most frequently is Staphylococcus Aureus

INFECTION

Radiologic Features The knee and hip are the most common

sites Joint effusion leads to distortion of the

fat folds Positive Walden storm's sign Rapid loss of joint space Bony ankylosis

INFECTION

Nonsuppurative osteomyelitis

(tuberculosis) General Consideration

Found in patients such as prepubertal

children, debilitated geriatric, silicosis,

AIDS sufferers, Lymphoma patients,

Alcoholics, corticosteroid and drug abusers

INFECTION

Etiology Mycobacterium tuberculosis Two mode of spread

Inhalation Ingestion

INFECTION

Radiologic Features Spinal tuberculosis is most common at L-I Early sign for spine are :

Lytic endplate destruction loss of disc height Anterior “ gouge defect “ Paraspinal swelling

INFECTIONAdvanced sign for spinal involvement are:

Vertebral body collapse Gibbus formation and obliteration of the

disc Tubercular arthritis is common in the hip and

knee Uniform joint space narrowing, early destruction

of the subchondral cortex, “moth-eaten” bone

destruction and juxtaarticular osteoporosis are

the cardinal sign of tubercular arthritis

Tuberculosis

Tuberculosis

TUMORS AND TUMORLIKEPROCESSES

METASTATIC BONE TUMORS

PRIMARY MALIGNANT BONE TUMORS Multiple myeloma Osteosarcoma Ewing’s Sarcoma

PRIMARY QUASIMALIGNANT BONE TUMOR Giant Cell Tumor

TUMORS

PRIMARY BENIGN BONE TUMORS Osteochondroma Osteoma Bone island Osteoid osteoma Simple bone cyst Aneurysmal bone cyst

TUMORS

Metastatic Bone Tumors General Consideration

The most common malignant tumors CNS tumors and basal cell Ca rarely Life threatening complication

Incidence 70% are metastatic, 30% are primary In females 70% from breast Ca

In males 60% from prostate Ca

TUMORS Radiologic Features

Technetium bone scan 80% of all metastases are located in the

central or axial skeleton

- Spine and Pelvis being a most common Alteration in bone density and architecture 75% osteolytic, moth eaten or permeative 15% osteoblastic Periosteal response is rare

Metastatic

TUMORSPrimary Malignant Bone Tumors Multiple Myeloma

Bone scan are cold Gross Osteoporosis may be the only early

sign Punched out lesions Vertebra plana or wrinkled vertebra Preservation of pedicles

Multiple Myeloma

Multiple Myeloma

TUMORS Osteosarcoma

75% of cases occurs in the 10 to 25 age Metaphysis of the distal femur, proximal

humerus are the most common sites Permeative or ivory medullary lesion in

metaphysis of a long tubular bone A sunburst or sunray periosteal response Cortical disruption with soft tissue mass

formation Sclerotic – Lytic – Mixed lesion

Osteosarcoma

Osteosarcoma

TUMORS Ewing’s Sarcoma

Most cases occur in the 10 – 25 age range May mimic infection Diaphyseal permeative lesion Femur, tibia and fibula Onion skin periosteal response Most common primary malignant bone

tumor to metastasize to bone

Ewing’s Sarcoma

TUMORSPrimary quasimalignant bone tumor Giant cell Tumor

Osteoclastoma 20-40 years is the usual age range Distal femur, proximal tibia

distal radius, proximal humerus Metaphysis and extend to subarticular Radiolucent, eccentric Soap Bubble appearance

Giant Cell Tumor

TUMORPrimary Benign Bone Tumors Osteochondroma

Painless and hard mass near a joint Humerus, tibia, femur, ribs Two types : - sessile

- pedunculated Coat hanger exostose – cauliflower mass The cortex and spongiosa blend

imperceptibly

Osteochondroma

TUMOR

Osteoma A rise in membranous bones Sinuses – frontal, ethmoid

Mandible

Skull bones Homogenously opaque

Osteoma

TUMOR

Bone Island Epiphyseal, metaphyseal Medullary Round – oval : Long axis oriented

Smooth or radiating border

Opaque

Normal adjacent cortex

May change size

TUMOR

Osteoid osteoma Consists a nidus, that usually 1 cm or less Target calcification Most common location is in the cortex Radiolucent nidus surrounded by perifocal

reactive sclerosis

Osteoid Osteoma

TUMOR

Simple Bone Cyst Expansile radiolucent Proximal humerus, femur, calcaneus No periosteal reaction Pathologic fracture

Aneurysmal Bone Cyst Some lesion may reach 8 – 10 cm Cortical ballooning “ blown out app”

Aneurysmal Bone Cyst

Aneurysmal Bone Cyst

ARTHRITIC DISORDERS

Degenerative Disorders Degenerative Joint Disease etc

Inflammatory Disorders Rheumatoid Arthritis etc

Metabolic Disorders Gout etc

ARTHRITIC Degenerative Joint Disease

Osteoarthritis – Osteoarthrosis Asymmetric distribution Non uniform loss of the joint space Osteophytes Subchondral sclerosis Subchondral cyst Loose bodies Subluxation

Osteoarthrosis

ARTHRITIC Rheumatoid Arthritis

Generalized Connective tissue disorder Highest incidence among the 40 – 50 year Symmetric peripheral joint pain and swelling Early : - Soft tissue swelling

Marginal erosions

Osteoporosis - Periostitis

Loss of joint space

Late : - Ankylosis

Deformities

Rheumatoid Arthritis

Rheumatoid Arthritis

ARTHRITISGout

Disorder of purin metabolism Deposits of Sodium monourate crystals

into cartilage, synovium, periarticular

and subcutaneous tissues Dense soft tissue Tophi, preservation

of joint space, Bone erosions (marginal

periarticular) “overhanging margin sign” Metatarsophalangeal joint

Gout

QUESTIONS

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