Published on March 20, 2014
INTRODUCTION TO SKELETAL IMAGING Muhammad Bin Zulfiqar PGR 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
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
TRAUMA Types 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
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
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
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
TRAUMA Fracture 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
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)
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
INFECTION Advanced 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
TUMORS AND TUMORLIKE PROCESSES 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
TUMORS Primary 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
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
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
TUMORS Primary 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
TUMOR Primary 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
TUMOR Osteoma A rise in membranous bones Sinuses – frontal, ethmoid Mandible Skull bones Homogenously opaque
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
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
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
ARTHRITIS Gout 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
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