OSTEOPOROSIS IMAGING

1
OSTEOPOROSIS

• Presenter- Dr Surendra K L
• Dept.of radio diagnosis, BMCRI,
  Bangalore.

2
APPROX. ONE IN TWO WOMEN ONE IN FOUR MEN OVER
AGE OF 50 YEARS WILL HAVE OSTEOPOROSIS RELATED
FRACTURE.

• Osteoporosis, is the most common of all metabolic
  bone disorders esp. in elders, is defined by the
  WHO as
• A SKELETAL DISEASE, CHARACTERIZED BY LOW BONE
  MASS AND MICRO-ARCHITECTURAL DETERIORATION OF
  BONE TISSUE, WITH A CONSEQUENT INCREASE IN BONE
  FRAGILITY AND SUSCEPTIBILITY TO FRACTURE

3
Learning objectives- to know

• Typical findings of osteoporosis at conventional
  radiography.
• Integrated imaging approach to osteoporosis.
• Imaging appearances so that we can
  differentiate osteoporosis from other metabolic
  bone diseases which have similar findings.

4
OSTEOPOROSIS OVER VIEW
5
(No Transcript)
6

• Localized Osteoporosis-
• Focal losses of bone density affecting small area
  of bone
• usually it is due to local disease such as
  inflammatory arthritis, neoplasm, or infection.

• Generalized Osteoporosis -
• Bone density is decreased in the majority of the
  skeleton, especially in the axial components of
  the spine, pelvis, and proximal long bones.
• Most common type
• Eg- postmenopausal and senile osteoporosis.

• Regionalized Osteoporosis-
• Loss of bone density confined to a region or
  segment of the body, such as an entire limb or
  portion of a limb
• most typical example is- the osteoporosis that
  occurs after immobilization of a limb in case of
  fracture.

7
BONE ARCHITECTURE

• Bone type I collagen hydroxyapatite water

8
RISK FACTORS

• Potentially modifiable
• Alcohol, Tobacco
• Vit D deficiency
• Malnutrition
• Medical disorders- Cushings ,Renal disease,
  Malabsorption
• Medications - Steroids

• Nonmodifiable
• Advanced age
• Female sex - estrogen deficiency
• European or Asian ancestry
• Family history 

9
Pathogenesisimbalance b/w bone formation
bone resorption

• In normal bone, matrix remodeling is constant
• 10 of all bone mass will be undergoing
  remodeling at any point of time.
• Bone is resorbed by osteoclast cells after which
  new bone is deposited by osteoblast cells
• 3 inter related mechanisms ? osteoporosis -

10
Clinical manifestations- generalized osteoporosis

• Reduction in skeletal mass occurs gradually,
  becoming clinically observable in the 5th or 6th
  decade of life in females and in the 6th or 7th
  decade in males.
• Women are affected more frequently, with an
  approximate ratio of 41 over men.

ALL CHEMICAL MOLECULAR CHANGES ? LOSS OF
CANCELLOUS BONE ? SIGNIFICANT TRABECULAR
THINNING ? FRACTURES
11
Clinical manifestations

• Vertebral compression fractures are the hallmark
  of osteoporosis. Usually some trauma occurs
  with each compression fracture but in severe
  osteoporosis fractures can occur spontaneously
• Vertebral fractures typically occur _at_
  thoracolumbar junction midthoracic area
• Applied force usually causes crushing of the
  anterior aspect of the vertebral body ? anterior
  wedge fracture ?forward bending of spine ?
  kyphosis.
• Other than spine, common sites affected are -
  femoral neck intertrochanteric region ,distal
  radius, tibia.
• Of all osteoporotic fractures, hip fractures
  cause the greatest morbidity and mortality

12

• Various modalities include -
• CONVENTIONAL RADIOGRAPHY- for qualitative semi
  quantitative evaluation.
• DUAL-ENERGY X-RAY ABSORPTIOMETRY (DEXA) and
  QUANTITATIVE CT - quantify bone mineral content
  assess bone loss.
• MORPHOMETRY Assessment of presence of fractures
• ULTRA SONOGRAPHY -provides important information
  about bone properties.
• MICRO-CT and HIGH-RESOLUTION MRI- improved
  assessment of the bone micro-architecture.

13
Conventional radiography

• Imaging appearance is same irrespective of the
  cause
• Able to detect bone loss only when loss is gt30
• Main radiographic features are-
• INCREASED RADIOLUCENCY
• CORTICAL THINNING
• ALTERED TRABECULAR PATTERNS
• FRACTURE DEFORMITY

Lateral radiograph of the dorsal spine shows
generalized severe osteopenia with increased
radiolucency of vertebral bodies and prominent
but thin cortical rim.
14
INCREASED RADIOLUCENCY- thinning/loss of the
trabeculae

• Trabecular bone responds to metabolic changes
  faster gt cortical bone.
• Trabecular bone changes are most prominent in the
  axial skeleton in the ends of the long bones
• Trabecular bone loss occurs in a predictable
  pattern.

15

• OSTEOPOROSIS. A-C. Spine.
• Diminished density of the vertebral bodies and
  the thinned but relatively prominent cortical
  endplates.

16

• OSTEOPOROSIS SPINAL TRABECULAR CHANGES.
• Lateral Lumbar Spine - trabecular patterns are
  well seen with vertical trabeculae appearing more
  prominent.
• Lateral Thoracic Spine - similar findings A
  minimal anterior wedge compression deformity
  (arrow).

17

• Lateral Lumbar Spine Pseudo-Hemangioma -
  accentuated vertical trabecular patterns of
  multiple segments? pseudo-hemangiomatous
  appearance. This is a manifestation of early
  stage will be last in advanced stages.
• B. Lateral Thoracolumbar Spine Haemangioma is
  most common benign tumour of the spine presents
  with similar accentuated vertical trabecular
  markings (corduroy cloth appearance) but is
  localized to only one level (arrow).

18
CORTICAL THINNING -due to osseous resorption in
the cortex.

• The structural changes seen in cortical bone
  represent bone resorption at 3 different sites of
  cortex .
• All these sites responds differently to different
  metabolic stimuli.
• Cortical thinning also occurs in predictable
  pattern.

19
Convectional radiography - Axial skeleton changes

• Loss of trabecular bone thinning of the cortex
  ? well-demarcated outline of the vertebral body
• picture framing or empty box

Radiograph of a single vertebra showing
characteristic features of osteoporosis- i.e.
increased radiolucency ,a well-demarcated
cortical rim, and accentuation of vertical
trabeculae.
20
Convectional radiography - Axial skeleton
changes- FRACTURE DEFORMITIES

• Compression fractures are usually occur in
  thoracolumbar junction but can occur anywhere .
• Isolated fractures above T7 level is very rare in
  osteoporosis if present should check for other
  causes.
• No. of vertebral fractures correlate with degree
  of osteoporosis.
• Fractures can be -
• Wedge fractures - when anterior height is reduced
  compare to posterior height,
• Endplate fractures - when the mid height is
  reduced compare to posterior height,
• Crush fractures - when all the heights of a
  vertebra are reduced compare to adjacent
  vertebrae.
• Remember-
• Because the posterior height of the thoracic
  vertebrae is normally 13 mm gt anterior height, a
  height loss gt 4 mm is considered a true vertebral
  fracture this criteria can also be used for
  lumbar vertebrae.

Lateral radiograph of the dorsal spine shows a
wedge fracture (arrow) associated with severe
osteopenia and kyphotic deformity.
21
OSTEOPOROSIS -VERTEBRAL BODY CONFIG-URATIONS.

1. Normal.
2. Normal with Pencil-Thin Cortices.
3. Wedge Shape Owing to Anterior Loss of Height.
4. Plana with Both Anterior and Posterior Collapse.
5. Biconcave (Fish Vertebra) due to Endplate
   Depression.
6. Angular Endplate Depression from Acute Fracture.

22

• VERTEBRAL BODY SHAPE CHANGES
• Lateral Thoracic Spine
• changes in vertebral body shape can be observed
• Wedge (w),
• Plana (p) PAN CAKE VERTEBRA
• Biconcave (b) - FISH, CODFISH, FISH-MOUTH,
  HOURGLASS VERTEBRAE
• Also, the thoracic kyphosis has increased.

23

• OSTEOPOROSIS BICONCAVE ENDPLATES (FISH
  VERTEBRAE) -
• Lateral Lumbar Spine - endplates are markedly
  concave in contour at multiple levels. This
  configuration occurs when there is loss of
  vertebral body strength
• AP Lumbar spine - Alaskan King Salmon Spine
  -endplates are deeply depressed centrally,
  creating an distinct appearance (arrows).

ALASKAN KING SALMON SPINE
24
Convectional radiography - Axial skeleton changes
Semi quantitative scoring system spinal
fracture index

• Use- To grade the severity of vertebral fractures
  
• Their system have - 4 grades
• Grade 0 - No fracture
• Grade 1- Mild fracture (2025 reduction in
  vertebral height compared with adjacent normal
  vertebrae)
• Grade 2 - Moderate fracture (2540 comparative
  reduction in height)
• Grade 3 - Severe fracture (gt40 comparative
  reduction in height).
• From this - a SPINAL FRACTURE INDEX is calculated
  i.e. sum of all grades given to the vertebrae /
  number of vertebrae evaluated.

25
Convectional radiography Appendicular skeleton
changes

• Changes are first apparent at the ends of long
  and tubular bones - due to the predominance of
  trabecular bone . Main sites where these changes
  seen are - HAND, PROXIMAL FEMUR, CALCANEUS.
• Corticomedullar index calculated from 2nd
  metacarpal bone represents a good semi
  quantitative measure for grading osteoporosis .
• Jhamaria index calculated from evaluation of
  trabecular pattern from calcaneus also used for
  semi quantification.
• Note - Earlier Metacarpal radiogrammetry and
  morphometry were used as quantitative methods for
  assessing the skeleton, However, these technique
  are now rejuvenated DEXA.

26
Convectional radiography Appendicular skeleton
changes - Semi quantitative scoring system
femoral index

• There are 5 Trajectorial groups of trabeculae
  in femur head
• Principal compressive,
• Secondary compressive,
• Greater trochanter,
• Principal tensile,
• Secondary tensile

• Principal compressive (curved white arrow),
• Secondary compressive (black arrow),
• Principal tensile (black arrowhead),
• Secondary tensile (white arrowhead), and
• Greater trochanter (straight white arrow)

These trabeculae in the proximal femur will
disappear in a predictable sequence.
27
(No Transcript)
28
OSTEOPOROSIS PELVIS AND BILATERAL FEMURS. AP
PELVIS- -Within the femoral necks- Cortices are
thin and there is relative accentuation of
remaining trabeculae esp . the principal
compressive trabeculae (arrows)
29
OSTEOPOROSIS INTERTROCHANTERIC FEMORAL FRACTURE.
AP HIP - Note the fracture through the
intertrochanteric region. NOTE- Fractures
of the proximal femur are the most common severe
presentation of osteoporosis. Such fractures
can occur elsewhere within the proximal femur,
including subcapital, midcervical, basocervical,
and subtrochanteric locations
30

• OSTEOPOROSIS EXTREMITY MANIFESTATIONS.
• AP Shoulder.
• AP Knee.
• Note the decreased density, trabecular
  enhancement, and thin cortices.

31
OSTEOPOROSIS insufficiency fractures

• Occur when the elastic strength of the bone is
  not sufficient to withstand normal physiological
  stress.
• Predisposing bone-weakening disorders- include
  osteoporosis, radiation necrosis, osteomalacia,
  Pagets disease, and fibrous dysplasia.
• In osteoporosis - common locations for
  insufficiency fractures are the sacrum, pubis,
  acetabulum, spine distal radius
• Clinically, pain is the major symptom _at_ fracture
  site
• Bone scans are the most sensitive imaging
  modality for demonstrating insufficiency
  fractures

32
Sacral - insufficiency fractures

• Most common cause of of the sacrum is senile
  and postmenopausal osteoporosis with a h/o recent
  fall
• Onset occurs after age 65 and
• women gt men
• Conventional radiography is less sensitive
  modality - detect fractures in lt 5 of cases.
• Axial CT bone windows clearly identify the
  fracture zone in gt 90 of cases.
• Most sensitive method of detection is
  Technetium-99m isotopic bone scan

33
Bone scan - Three patterns of sacral
insufficiency fractures occur based on bone scan
appearance

• H pattern (butterfly or Honda sign) - Bilateral
  vertical fractures through the sacral ala are
  connected by a transverse fracture through the
  S2, S3, or S4 bodies.
• I pattern - A single vertical fracture passes
  through the sacral ala. This is the most common
  form of sacral insufficiency fracture
• Arc pattern - A linear transverse fracture passes
  horizontally across the sacrum.

• INSUFFICIENCY FRACTURE OF THE SACRUM -L5 vertebra
  (L5) , adjacent ilium (I) -
• Dense uptake of the isotope within the lateral
  sacrum as two vertical components corresponding
  to the sites of fracture (arrows).
• Transverse linear uptake (arrowhead).- between
  2 vertical components corresponding to
  transverse fracture through the S2 body,
• Combination of these 3 components ? H-shaped
  lesion called Honda sign.

34
CT Axial Scan-INSUFFICIENCY FRACTURE OF THE
SACRUM.. -Two symmetrically located insufficiency
fractures in the lateral sacrum (arrows).
Displacement of the anterior cortex of the
sacrum within 1 cm of the sacroiliac joint is a
reliable feature ( arrow head) Fracture line is
usually lateral to sacral foramina this is in
contrast to traumatic fractures, which usually
extend into the foramina or central canal
35
Radiograph of AP Pubis INSUFFICIENCY FRACTURE OF
THE PUBIS. - Within the body of the pubis
there is a poorly defined zone of rarefaction
(arrows). Irregularity of the articular margin
is also noted.
36
Dual-Energy X-Ray Absorptiometry

• What is DEXA scan ?
• DEXA scanning, is currently the most widely used
  method to measure BONE MINERAL DENSITY
  currently DEXA is the standard of reference for
  the clinical diagnosis of osteoporosis with bone
  densitometry.
• Equipment procedure ?
• Mobile x-ray source (fan beam) a couch for the
  patient, a detection system ( multiple
  detectors) that detects radiation emerging from
  the bones.
• The x-ray source is under the couch and moves
  together with the detection system, which is
  located opposite the x-ray source and over the
  patient's body
• Takes 5 min per site.

37
Dexa principle

• X-ray beam used in DEXA is - composed of 2
  different photon energies (constant and pulsed).
  The 2 energies are used in order to compensate
  for the different attenuation coefficients of the
  bone soft tissues
• After the photons are passed through bones soft
  tissue ? intensities of high-energy low-energy
  photons are analyzed separately
• Using computer algorithm, attenuation values of
  soft tissues are subtracted, leaving only the
  attenuation values of bone.
• Now, attenuation values of bone obtained are
  compared with standard values higher
  attenuation indicates higher density

38
Dexa principle

• DEXA PRINCIPLE -
• DEXA examination gives 2 measurements for each
  reagion of interest - bone mineral content (in
  grams ) area of measured site ( in sq.cm )
• Bone mineral content / area BMD ( gm./sq.cm)
• BMD is expressed in terms of standard deviation
  as a T SCORE Z SCORE .
• Results are reported as numeric values for the T
  score and Z score and as a graphic curve which is
  normalized for gender and age

DXA image of the proximal femur shows different
ROI i.e - femoral neck (rectangle), Ward area
(square), and trochanter Each ROI is defined
and analyzed with the DXA examination. Although
areal BMD is obtained for a number of different
sites, only the femoral neck and total hip are
used for clinical diagnosis of osteoporosis (WHO
T score lt -2.5).

• On a PA view DXA image of L1 through L4, the
  shapes of the vertebrae are created primarily by
  the posterior elements.
• For each vertebra- bone mineral content (in
  grams) and area (in square centimeters) are
  obtained
• Results are generally expressed as BMD for all
  four vertebrae.

39
Dexa Scoring

• T SCORE -
• Difference b/w the patients BMD and the mean BMD
  of a standard young adult population ( PEAK BONE
  MASS)
• Z SCORE age matched BMD-
• Difference b/w the patient's BMD and the mean BMD
  of age- and gender-matched controls.
• The Z score is particularly important in patients
  aged 75 years or older.

• WHO classification of BMD - based on T score
  include -
• Normal ( 1.0)
• Osteopenia (lt 1.0 but gt 2.5)
• Osteoporosis ( 2.5)
• Severe osteoporosis ( 2.5 with fragility
  fracture)
• This definition is applied to DEXA measurements
  made in the lumbar spine, proximal femur, and
  forearm, but not to measurements made with other
  techniques (eg, quantitative CT) or to DEXA
  measurements made at other anatomic sites (eg,
  calcaneus).

40
Advantages
DISADVANTAGES-

• Low radiation dose,
• Low cost, easy to use
• Rapid
• Highly reproducible
• Can predict future fractures to certain extent

• DEXA is 2D technique have inherent limitations.
  
• It cannot help distinguish between cortical and
  trabecular bone.
• It cannot help to discriminate between changes
  due to bone geometry (eg, in case of increase in
  the third dimension, a false value is obtained
  but now C arm structured lateral scanners are
  available which considers 3rd dimension also.)
• Since fracture occurrence depends on other
  factors other than BMD , it cannot help to
  completely discriminate between patients who have
  fractures those who dont have.

41
Quantitative CT axial and peripheral

• Quantitative CT provides separate estimates of
  trabecular and cortical bone BMD
• Gives results as a true volumetric mineral
  density in mg / cubic cm.
• It can be performed at axial sites as well as
  peripheral sites

• Principle ?
• Using commercial CT scanners which are calibrated
  for bone mineral reference standard , 8-10 mm
  thick sections are obtained through the mid plane
  of each vertebra ( usually 2-3 vertebrae b/w
  T12-L4)
• ROI is positioned manually in the anterior
  portion of trabecular bone in the vertebral body
  for analysis.
• Scan is performed ? CT attenuation of selected
  ROI is measured in Hounsfield units.
• Now, Software will convert HU into mg of calcium
  hydroxyapatite per cubic cm.
• These values are expressed as absolute values or
  T score or Z score.

Axial CT scan shows placement of an elliptic ROI
to measure the volume of purely trabecular bone
in a vertebral body.
42
Advantages -
DISADVANTAGES-

• Selective measurement of trabecular bone- which
  is the main determinant of compressive strength
  in vertebrae .
• And Because of 3D spatial resolution,
  quantitative CT allows assessment of both
  volumetric BMD macro architecture ? detailed
  understanding of the changes associated with
  advancing disease or response to drug therapy.

• High radiation
• High cost
• Poor longitudinal assessment
• High operator dependence

Three-dimensional volume-rendered reformatted
image of the proximal femur which is used to
evaluate BMD with quantitative CT.
43
Morphometry

• Vertebral morphometry is a quantitative method to
  identify osteoporotic vertebral fractures based
  on the vertebral height measurements.
• on conventional radiographs, osteoporotic
  vertebral fractures often missed, often less
  quantified more subjective ? To overcome this,
  Quantitative vertebral morphometry is
  introduced.
• These measurements may be obtained from
  conventional spine radiographs (morphometric
  x-ray radiography) or absorptiometric images
  (morphometric x-ray absorptiometry).
• Currently, combination of Semi quantitative
  Visual Quantitative Morphometric Methods is
  the best approach for defining vertebral
  fractures,
• Morphometric x-ray absorptiometry is most widely
  used technique for vertebral body height
  measurement.

44
MORPHOMETRY PRINCIPLE
Three ratios are calculated 1. Anterior
height / posterior height ? if reduced ? wedge
2.Middle height / posterior height ? if
reduced ? biconcave 3. Posterior height of
given vertebra/ Posterior height of adjacent
vertebra ?if reduced? crush
Lateral radiographs showing how to define
vertebral edges and measure vertebral heights for
quantitative diagnosis of fracture
45
Quantitative USg

• US waves are affected by amount of mineral
  content in bone also by its structure? hence it
  gives quantification information about bone
  fragility.
• USG, off course does not produce bone images but
  can be used to measure quantitative parameters
  tissue properties of bone.
• Currently, used as screening tool with
  confirmation by DEXA scan.
• Skeletal sites that can be studied with USG are
  CALCANEUS, DISTAL METAPHYSIS OF PHALANX, RADIUS,
  TIBIA.
• Among all, calcaneus is best because it have 95
  of trabecular bone.

46

• Quantitative US results can be expressed as
  absolute values or as T scores and Z scores but
  WHO criteria given for DEXA cannot be used with
  quantitative US.
• Advantages no radiation, small size, quick
  measurement, low cost
• Disadvantages- lack of sensitivity- so not
  suitable for long term monitoring.

47
Micro CT - Gives details about microarchitecture
of bone

• Structure or spatial arrangement of bone at
  microscopic level will provide additional
  information to predict fracture risk
• Trabecular bone microarchitecture is of
  particular importance, since osteoporosis targets
  trabeculae.
• Clinical whole-body multi-detector CT does not
  offer a spatial resolution sufficient to reveal
  true trabecular architecture. However, it gives
  idea about texture of the trabecular bone which
  correlates well with measurements of the true
  trabecular network.
• At the highest end of the resolution hierarchy,
  micro-CT is the supreme modality -which gives
  resolutions up to 6 µm so that we can visualize
  fine trabecular structures.

48
Micro CT

• Three-dimensional reconstructed models of the
  specimens are obtained parameters of bone
  microarchitecture are analyzed with software
  which include -
• Bone Volume Fraction (Trabecular Bone Volume /
  Total Volume)
• Trabecular Number (No. Of Trabeculations /Mm),
• Trabecular Thickness
• Distance Between Trabeculae
• Bone Surfacevolume Ratio (Total Surface Area Of
  Trabeculation / Total Volume),
• Structure Model Index (Referring To The Platelike
  Or Rodlike Structure Of Trebeculation), And
• Degree Of Anisotropy (Direction Of Trabeculation)

Multidetector CT scan clearly depicts the
trabecular bone.
49
Micro CT

• Structural parameters obtained with micro-CT
  correlate well with parameters obtained at
  histologic analysis
• CT has the advantage of allowing direct
  visualization of the bone but the disadvantage of
  considerable amount of radiation.

Micro CT images of the spines of a healthy
23-year-old woman (left) and an 85-year-old woman
with osteoporosis. The bone trabeculae structure
of the 85-year-old woman is deteriorated and the
bone mass is reduced.
50
HIGH RESOLUTION MRI

• Nonionizing modality that can produce
  three-dimensional images
• When imaging trabecular bone with MRI - one must
  be aware that trabecular bone itself is not
  visualized. Instead, the trabecular network is
  revealed indirectly through marrow visualization
  and appears as a signal void surrounded by
  high-signal-intensity fatty bone marrow.
• High-resolution 3-T bone MR imaging is the choice
  to assess sites like- calcaneus, knee, and
  wrist.
• Recent technologic developments have made
  quantitative MR imaging as clinically practicable
  modality.

51
High resolution mri

• The assessment of bone architectural status and
  changes with MR imaging is still not common, and
  this modality is not part of daily clinical
  practice hence, there are no guidelines for its
  use.
• Nevertheless, MR imaging is a promising technique
  for monitoring treatment effects.

high-resolution MR image of the calcaneus depicts
the trabecular bone structure.
52
Regional osteoporosis- Reflex Sympathetic
Dystrophy Syndrome -post-traumatic
osteoporosis, Sudecks atrophy, acute bone
atrophy, and causalgia

• A post-traumatic bone disorder characterized by
  an acute painful osteoporosis
• Now it is called - complex regional pain syndrome
  - somatic, psychological, behavioural
• Clinical Features -
• gt 50 years of age.
• Usual sites - hand shoulder
• Most notable feature - progressive onset of pain,
  stiffness, swelling, and atrophy at and distal to
  the site of injury

• Pathologic Features -
• Reflex over activity of the sympathetic nervous
  system ? trophic changes in bone Hyperemia of
  bone ? osteoclastic resorption
• Radiologic Features -
• Patchy, mottled osteoporosis.
• Metaphyseal localization. tunneled cortices, and
  endosteal resorption
• Later, more generalized osteoporosis.
• No joint disease.

53
Radiograph of Bilateral PA Hands A. Distinct
loss of bone density in the affected hand
(arrow), especially in the peri-articular regions
B. Normal other side.
54
Regional osteoporosis - Disuse and
Immobilization Osteoporosis

• Most common causes -
• Traumatic injuries that are immobilized,
• motor paralysis, and
• inflammatory lesions of bones and joints

• 4 radiologic patterns of disuse atrophy
• Uniform uniform lucency
• Spotty - Localized circular lucencies
• Bands - Linear transverse lucencies
• Cortical lamination or scalloping.

Changes appear on plain film after 7-10 days of
immobilisation becomes extreme by 2 months.
55

• DISUSE OSTEOPOROSIS.
• Lateral Elbow bones are demineralized in a
  uniform manner following immobilization
• PA Wrist - showing spotty form of the wrist
  after immobilization for an elbow fracture.
• PA Foot showing spotty type of disuse
  osteoporosis of foot after immobilization for an
  ankle fracture.

56
Transient Regional Osteoporosis- transient bone
marrow edema syndrome

• NO ASSOCIATED CAUSE SUDDEN AND REVERSIBLE
  AFFECTS PERIARTICULAR BONE.

• Transient Osteoporosis of the Hip -
• Peculiar disorder of unknown origin
• Actually represents a reversible stage of
  avascular necrosis.
• Age of onset - 20 and 40 years, more in males.
• It is interesting that in pregnant females left
  hip is exclusively involved

• Regional Migratory Osteoporosis
• Males most commonly affected.
• Usually in lower extremities.
• Migration from one joint to another
• Represent a highly localized exaggerated
  process of diffuse osteoporosis

57
Differential diagnosis of generalized osteoporosis
In hyperparathyroidism, subperiosteal bone
resorption is the most characteristic
radiographic feature, with multiple erosions at
the radial site of 2nd 3rd phalanges
,sacroiliac joints, and pubic symphysis.

• Hyperparathyroidism
• Hypercortisolism
• Malignant diseases
• Renal osteodystrophy
• Paget's disease
• Posttraumatic deformity

Conventional radiograph of the second phalanx in
hyperparathyroidism patient showing subperiosteal
bone resorption with indistinct delineation of
the outer cortical border (arrow).
58
Differential diagnosis of generalized
osteoporosis- CORTICOSTEROID OSTEONECROSIS

• Hypercortisolism is the most common cause of
  medication-induced generalized osteoporosis-
• The typical radiographic appearance is
  generalized osteoporosis at trabecular sites,
  decreased bone density fractures of the axial
  appendicular bones.
• Another characteristic finding of
  steroid-induced osteoporosis is marginal
  condensation of the vertebral bodies resulting
  from exuberant callus formation
• INTRAVERTEBRAL VACUUM CLEFT SIGN

INTRAVERTEBRAL VACUUM CLEFT SIGN- A sub-endplate
linear radiolucent collection of gas can be
identified representing VACCUM CLEFT SIGN
(arrowhead).
Hazy intra-body density, representing marginal
condensation of vertebral body with hypertrophic
callus formation (arrows).
59
Differential diagnosis of generalized
osteoporosis- MALIGNANCIES
The most important DD in elderly with vertebra
fractures is malignant disease (eg, multiple
myeloma or metastatic bone disease) . In
malignant cause- Fractures are usually located
above the T7 level with a soft-tissue mass
osseous destruction. Fractures are usually seen
in the posterior part of the vertebral body A
concave posterior vertebral border is more likely
a sign of benign osteoporotic fracture, whereas a
convex posterior border suggests malignant
disease. CT and MR imaging are helpful in
differentiating between osteoporotic and
malignant fractures
60
Differential diagnosis of generalized osteoporosis
In renal osteodystrophy, bone changes are complex
and are caused by osteomalacia, osteoporosis, and
secondary hyperparathyroidism. Vertebral
deformities typically have a rugger jersey
appearance, because of subchondral sclerosis
occurring beneath the endplates of the vertebrae.
Prominent linear sub-endplate densities at
multiple levels giving alternating
dense-lucent-dense appearance similar to the
transverse bands of a rugby sweater (rugger
jersey spine).
In Paget disease, the vertebrae have a dense
trabecular structure with a more dense periphery
(window pane appearance). The vertebrae are
reduced in height but increased in
cross-sectional diameter due to structural
weakness and softening of the bone.
61
Differential diagnosis of generalized osteoporosis

• Another important possible diagnosis in
  osteoporotic vertebral fractures is posttraumatic
  deformity.
• In posttraumatic deformities - the diameter of
  the vertebrae is enlarged substantial
  secondary degenerative changes with osteophyte
  formation.
• MR imaging is useful for determining the local
  pathologic changes in a fractured vertebra-
• Evidence Of Marrow Edema- A Sign That A Fracture
  Is Recent.
• Preservation Of Some Normal Marrow Signal,
  Especially In The Posterior Elements Pedicles
  (In Osteoporotic Fractures - Signal Abnormality
  is seen Adjacent To The Fracture Site In A
  Bandlike Configuration.).
• The Involved Vertebral Body Shows Homogeneous
  Enhancement With Gadolinium .

62
Prevention

• Prevention of osteoporosis begins during
  childhood.
• Factors that augment bone mass (a diet rich in
  calcium and vitamin D, physical activity) should
  be encouraged, and
• Factors that diminish bone mass (smoking, alcohol
  consumption) should be discouraged.
• Fall prevention should be a part of routine care
  for all postmenopausal women and elderly people

63
Current Treatment of Osteoporosis

• Two main classes of medications are available for
  postmenopausal osteoporosis
• Antiresorptive agents, which decrease bone
  resorption, and
• Anabolic agents, which promote bone formation.
• Besides hormone replacement therapy,
  antiresorptive agents approved by the FDA for the
  treatment or prevention of osteoporosis include
  bisphosphonates (alendronate, risedronate,
  ibandronate, and zoledronic acid), strontium
  ranelate, raloxifene, and calcitonin.
• Vertebroplasty, kyphoplasty, and skyphoplasty are
  surgical interventions that are indicated for the
  management of vertebral compression fractures in
  patients who are unresponsive to conventional
  pain relievers

64
FINALLY

• Osteoporosis is a metabolic bone disease that is
  characterized by low bone mass and
  microarchitectural deterioration of bone tissue,
  with a consequent increase in bone fragility and
  susceptibility to fractures.
• A correct diagnosis is fundamental for the
  identification of persons who need treatment and
  are at risk for complications.
• Advanced (and often complementary) technologies
  are being developed in an attempt to diagnose
  osteoporosis in early stages, thereby reducing
  social and economic costs preventing patient
  suffering.

65
references

• Title Orthopedic Imaging A Practical Approach,
  4th Edition, Editors Greenspan, Adam Copyright
  2004 Lippincott Williams Wilkins
• Essentials of skeletal radiology Yochum and
  Rowes 3rd edition
• Radio graphics article - Integrated Imaging
  Approach to Osteoporosis State-of-the-Art Review
  and Update

66
(No Transcript)