Imaging Approach To Generalized Increased Bone Density

By Dr Sachin

Intramembranous Ossification:Mesenchymal cells within embryonic connective

tissue Proliferates

Early Mesenchymal condensations

Differentiate directly

Osteoblasts

Skeletal Development

Mesenchymal Condensation

Cartilage Anlage (Model)

Bone Collar

Mesenchymal Cells Differentiate Into Prechondroblasts And Chondroblasts & Later In To

Chondrocytes

Calcification Of Bone Collar – Osteoclasts & Blood Vessels, Enter Primary Ossification Center

Endochondral Ossification

Osteoclast Invasion And Wave Of Resorbing Activity

Removal Of Calcified Cartilage

Woven Bone- The Primary Spongiosa

Further Remodeling -Woven Bone And The Cartilaginous Remnants

Replaced With Lamellar Bone

The Mature Trabecular Bone- Secondary Spongiosum

Growth in Bone Shape and Diameter (Modeling)

During Longitudinal Growth Of A Long Bone, Continuous Resorption By Osteoclasts Beneath

Periosteum

Progressively Destroys Lower Part Of Metaphysis Transforming It Into Diaphysis

DysplasiasOsteopetrosisPyknodysostosisCraniotubular dysplasias Craniotubular hyperostoses

MetabolicRenal osteodystrophy

Poisoning Chronic hypervitaminosis A Idiopathic

Caffey's diesase (infantile cortical hyperostosis)Idiopathic hypercalcemia of infancy Lead FluorosisHypervitaminosis D

Generalized Increased Bone Density In Children

Dysplasias Of Endochondral Ossification (Primary Spongiosa)

Failure In Resorption & Remodeling Of Primary Immature Spongiosa By Osteoclasts

Accumulation Of Calcified Cartilage Matrix Packing The Medullary Cavity- Osteopetrosis

- Pyknodysostosis

Target sites: tubular & flat bones, vertebrae, skull base, ethmoids, ends of clavicle

Defective Carbonic anhydrase function Lack of alkaline environment for osteoclast

function Defective osteoclast function

Types Infantile autosomal recessive osteopetrosis Benign adult autosomal dominant osteopetrosis

Osteopetrosis

Failure to thrive Cranial nerve entrapment (Optic nerve) Snuffling (nasal sinus architecture abnormalities) Hypercalcaemia Pancytopaenia (anaemia, leukopaenia and/or

thrombocytopaenia) Hepatosplenomegaly (extramedullary haemopoesis) Intracerebral haemorrhage (thrombocytopaenia) Lymphadenopathy Premature senile facies

Clinical Manifestations

Radiological Manifestations

Mandible : triangular opacity representing calcification within the secondary condylar cartilage ossification center

Paranasal sinuses : poorly pneumatized (ethmoid sinuses least severely affected)

Hypertelorism

Calvarium : high-attenuation inner table, a broad, low-attenuation diploic space, and a less high-attenuation outer table

“Hair-on-end" appearance : increased haematopoietic activity

Osteosclerosis in superior and inferior portions of the vertebral bodies -'sandwich' appearance

Autosomal dominant osteopetrosis

A lysosomal disorder due to genetic deficiency in Cathepsin K

Short stature particularly limbs Delayed closure of cranial sutures Frontal and occipital bossing Nasal beaking Obtuse mandibular gonial angle with relative

prognathism Segmentation defects

Pyknodysostosis

Errors in resorption & remodeling of secondary spongiosa, focal densities / striations◦Focal densities / striations◦Enostosis◦Osteopoikilosis◦Osteopathia striata

Dysplasias Of Endochondral Ossification (Secondary Spongiosa)

Dysplasias Of Intramembranous Ossification◦Target sites: flat bones, calvaria, bones of upper face, tympanic

parts of temporal bone, vomer, medial pterygoid

◦ Progressive diaphyseal dysplasia◦Hereditary multiple diaphyseal sclerosis (Ribbing disease)◦Hyperostosis corticalis generalisata

- Van Buchem disease- Sclerosteosis (Truswell-Hansen disease)- Worth disease- Nakamura disease

◦Diaphyseal dysplasia with anemia◦Oculodento-osseous dysplasia◦Trichodento-osseous dysplasia◦Kenny-Caffey syndrome

Hyperirritability

Soft tissue swelling

Cortical thickening

Bones commonly affected mandible, ribs, clavicle, ulna, any long bone but not spine

Kenny-caffey Syndrome/ Infantile Cortical Hyperostosis

◦Predominantly endochondral disturbance- Dysosteosclerosis- Metaphyseal dysplasia (Pyle disease)- Craniometaphyseal dysplasia- Frontometaphyseal dysplasia

◦Predominantly intramembranous defects- Melorheostosis- Craniodiaphyseal dysplasia- Lenz-Majewski hyperostotic dwarfism- Progressive diaphyseal dysplasia

MIXED SCLEROSING DYSPLASIAS

Diagnosed as an incidental finding

Monostotic, Monomelic, Or Polyostotic

Sclerotomal distribution

Dripping wax appearance or flowing candle wax appearance

Melorheostosis

Renal osteodystrophy Chronic hypervitaminosis A Lead Fluorosis Hypervitaminosis D

Secondary Causes Of Generalized Increased Bone Density In Children

Myelosclerosis/ Myeloproliferative disorders Metabolic◦Renal osteodystrophy

Poisoning◦Fluorosis

Neoplastic- Osteoblastic metastases : prostate and breasts- Lymphoma.

Mastocytosis : Paget's disease

Secondary Causes Of Generalized Increased Bone Density In Adults

Group of diseases

Too many of certain types of cells made in the bone marrow

Fibrosis of the bone marrow with extramedullary hematopoiesis

Myelofibrosis→Osteosclerosis

Chronic myeloproliferative diseases e.g. essential thrombocytopenia and polycythemia vera and chronic neutrophilic, eosinophilic, and myeloid leukemia

Acute myeloid leukemia & lymphocytic leukemia

Hodgkin's disease & non-hodgkin's lymphoma Hairy cell leukemia

Multiple myeloma

Fatigue, Weight Loss

Easy Bruising And Bleeding

Fever, Night Sweats

Splenomegaly

Gout And Renal Colic Due To Hyperuricemia

Clinical presentations

Replacement of the normal marrow cavity with fibrous tissue

with no trabecular or cortical disorganization

http://www.radswiki.net/main/images/a/ae/Myelofibrosis-001.jpg

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http://www.radswiki.net/main/images/5/5d/Myelofibrosis_MRI_001.jpg

A superscan appearance - intense symmetric activity in the bones with diminished renal and soft tissue activity on a Tc99m diphosphonate bone scan

Mastocytosis

Musculoskeletal abnormalities secondary to chronic renal failure, due to concurrent and superimposed

Osteomalacia (adults) / rickets (children) Secondary hyperparathyroidism (abnormal

calcium and phosphate metabolism) ◦Bone resorption ◦Osteosclerosis◦Soft tissue & vascular calcifications◦Brown tumours

Aluminum intoxication

Renal osteodystrophy

Osteopaenia : Early, thinning of cortices and trabeculae

Salt and pepper skull Subperiosteal resorption : on radial aspects

of middle phalanges of index and long fingers

Rugger-jersey spine Demineralization Soft tissue calcification

Radiological abnormalities

Renal failure - phosphate retention

Subsequent hyperplasia of parathyroid gland chief cells

Decrease in serum calcium and an increase in serum parathyroid hormone

Acts on kidneys

Increased osteoclastactivity - release of calcium from bone

Osteoblasts form an increased amount of osteoid in responseto bone resorption

Excess osteoid does not contain hydroxyapatite but appears

opaque on radiographs - Rugger jerseySpine

Rugger-jersey spine

D/d •Paget disease (“picture frame” vertebral body)•Osteoporosis

•Metastatic lesions

Fluorosis- Endemic areas (asia - india and china; rajasthan

and gujarat, andhra, punjab, haryana, M.P. And maharashtra,t.N.,W.B.,U.P.,Bihar and assam)

- Increased osteoclastic response

- Cortical thickening encroachment upon medullary cavity, ossification of ligamentous attachments

Toxins and Minerals

Metastatic disease ◦Prostatic carcinoma◦Breast cancer◦Transitional cell carcinoma (TCC)◦Multiple myeloma◦Lymphoma ◦Carcinoid◦Medulloblastoma◦Neuroblastoma◦Mucinous adenocarcinoma of the

gastrointestinal tract: , e.G. Colon carcinoma◦Lymphoma

Osteoblastic Metastasis

Hypercalcaemia, and increase in periosteal new bone with cortical thickening

Pseudotumour cerebri

D/D Infantile cortical hyperostosis : > 1yrs of age

Hypervitaminosis A

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