This document discusses various imaging modalities used in orthopaedics including plain film radiography, computed tomography, magnetic resonance imaging, ultrasound, bone scintigraphy, positron emission tomography, and bone densitometry. It provides details on the physics, clinical applications, advantages, and limitations of each technique. Recently developed imaging tools like fluoroscopy, contrast-enhanced ultrasound, elastography, and arthrography are also covered.

1. IMAGING IN
ORTHOPAEDICS
Presented by: Dr. BIPUL BORTHAKUR
PROFESSOR ,Dept of Orthopaedics,SMCH

2. INTRODUCTION
• The availability of diagnostic images to physical therapists
greatly depends on the practice setting
• The results from imaging studies should be used in conjuction
with other clinical findings
• In general , imaging tests have a high sensitivity ( few false
negatives ) , but low specificity ( high false positive rate )

3. IMAGING TECHNIQUES
• Plain film Radiography
• X – rays with contrast media
• Plain tomography
• Computed tomography ( CT )
• Magnetic resonance imaging ( MRI )
• Diagnostic Ultrasound
• Radionuclide imaging
• Single – photon emission computed tomography
( SPECT )
• Positron emission tomography ( PET )
• Bone mineral densitometry ( BMD )

4. PLAIN FILM RADIOGRAPHY
• First order & Most useful method of diagnostic imaging
• Provides information on size , shape , tissue density & bone
architecture
• Overview - Radiographic image
Radiographic interpretation
Diagnostic associations
Limitations

5. RADIOGRAPHIC IMAGE
• X- Rays :- part of elecro-magnetic spectrum - ability to penetrate
body tissues of varying densities
• Exposure to xray particles causes the film to darken , while on
areas of absorption , appear lighter on x-ray film
• Denser the tissue - lighter it appears on the film
• Structures in order of deceasing density
METAL > BONE > SOFT TISSUE > WATER ( BODY FLUID ) > FAT > AIR
BONE - Cancellous bone is less dense than cortical bone &
appear lighter than cortical bone

6. RADIOGRAPHIC INTERPRETATION
• Convenient sequence of examination is
Patient
Soft tissues
Bones
Joints
PATIENT - AGE - important criteria
< 10 yrs – ewing’s sarcoma
10 – 20 yrs - osteosarcoma
> 50 yrs – metastatic deposit

7. • SOFT TISSUES
1) GENERALIZED CHANGE - Muscle planes
Bulging - joint effusion ( hip ) / rheumatoid arthritis (
interphalangeal joint )
Displaced - tumours
Obliterated – infection
2) LOCALIZED CHANGE - in case of mass , soft tissue calcification ,
ossification , gas , radioopaque foreign body

8. BONES
Shape
Generalized change – bone density ( osteopenia/osteosclerosis)
abnormal trabeculations ( Paget’s disease )
sclerotic /lytic lesions ( diffuse metastatic infiltration)
Localized change - BENIGN TUMOURS – well defined , sclerotic
margin, smooth periosteal reaction
MALIGNANT TUMOUR - Ill defined areas , permeative
bone destruction & speculated periosteal reactions

11. JOINTS
JOINT SPACE
appears wider in children > adults
chondrocalcinosis ( lines of increased within radiographic
articular space )
SHAPE - narrowing / asymmetry of joint space
1) infection
2) inflammatory arthropathies
3) osteoarthritis
EROSIONS - Periarticular erosions - Rheumatoid arthritis , psoriasis
juxta articular erosions - Gout

12. DIAGNOSTIC ASSOCIATIONS
• Osteoarthritis -Narrowing of joint space+subchondral sclerosis +cyst
– Inflammatory arthritis -Narrowing of joint space + osteoporosis
+ periarticular erosions
– Infection / malignancy - Bone destruction + periosteal new bone
formation

13. • LIMITATIONS OF PLAIN RADIOGRAPHY
1) Exposure to ionizing radiation - radiation induced cancer
2) Provides poor soft tissue contrast

14. X RAYS WITH CONTRAST MEDIA
• SINOGRAPHY - simplest form of contrast radiography
• ARTHROGRAPHY -
knee – torn menisci , ligament tears , capsular ruptures
AVN ( femoral head ) in adults - torn flaps of cartilage
spine - diagnose disc degeneration ( DISCOGRAPHY )
small facet joints abnormalities ( FACETOGRAPHY )
MYELOGRAPHY - for diagnosing nerve root lesion

16. PLAIN TOMOGRAPHY
• Provides image ‘ focussed ‘ on a selected plane
• Useful in diagnosing segmental bone necrosis & depressed
fractures in cancellous bone
• Conventional tomography has been supplanted by CT & MRI

17. COMPUTED TOMOGRAPHY ( CT )
• CT SCAN produces sectional images through selected tissue
planes - but with greater resolution
• As compared to conventional tomography , computed tomography
produces trans – axial images ( transverse anatomical sections )
• In new multislice CT scanners , 3D surface rendered
reconstructions & volume rendered reconstructions - help in
demonstrating anatomical contours

18. CLINICAL APPLICATIONS OF CT SCAN
• Since it provides excellent contrast resolution and spatial localization
it’s ideal for evaluating
Acute trauma to the head , spine , chest , abdomen & pelvis
• Better than MRI - fine bone detail & soft tissue calcification
• Invaluable tool in pre operative planning in secondary fracture
management
• Routinely used for vertebrae , acetabulum , tibial plataeu , ankle & foot
injuries - complex ( intraarticular fractures ) & fracture dislocations
• Assessment of bone tumours ( size & spread )
• Can be employed for guiding soft tissues & bone biopsy

20. LIMITATIONS OF CT SCAN
• Provides relatively poor soft – tissue contrast
when compared with MRI
• Major diadvantage is - high radiation exposure

21. MAGNETIC RESONANCE IMAGING ( MRI )
• Provides superb soft tissue contrast , distinguishing
different soft tissues eg. Ligaments , tendons ,
muscle & hyaline cartilage
• Utilizes Non – Ionizing radiation
• Contraindicated in patients with pacemakers &
possible metallic foreign body

22. MRI PHYSICS
Patient’s body placed in a strong magnetic field
Body’s protons ( having + charge ) align themselves along
this
strong magnetic field
Spinning protons further excited by radiofrequency
pulses
spinning positive charges induce their own small
magnetic field , & also produce a signal as they relax
( slow down ) at different -
rates

23. • Proton density map is recorded from these signals and
plotted in x, y , z coordinates
• T1 weighted ( T1W) images - high spatial resolution & good
anatomical looking pictures
• T2 weighted ( T2W ) images - physiological characterstics of
tissue
• Proton density ( PD) images - balanced / intermediate – are
combination of T1 & T2 images
• Fat suppression sequences - assessing soft – tissues & bone
marrow
oedema

24. CONTRAST ENHANCED – MRI
• Enhancement by intravenous contrast – active blood supply &
leaky cell membrane
• INDIRECT ARTHROGRAPHY
Gadolinium compounds – Intravenous – secreted through joint
synovium - into joint effusion
No additional distension of the joint
• DIRECT ARTHROGRAPHY
Dilute gadolinium ( 1:2000 concentration ) solution directly
punctured into joints under image guidance
Distention of joint capsule occurs

25. CLINICAL APPILICATIONS OF MRI
• Ideal for non – invasive imaging of the musculoskeletal system - excellent
anatomical detail , soft tissue contrast & multiplanar capability
• MRI of hip , knee , ankle , shoulder & wrist is common - can detect early
changes of bone marrow oedema & osteonecrosis
• MRI Knee - for meniscal tears & cruciate ligament injuries
• Fat suppresion sequences – extent of perilesional oedema & IV contrast –
active part of the tumour ( it distinguish vascular from avascular tissues
• Direct MRI arthrography - distent joint capsule
diagnose labral tears in shoulder & hip
ankle – assess integrity of the capsular ligaments

27. LIMITATIONS OF MRI
• Conventional radiographs & CT are more
sensitive to
SOFT TISSUE CALCIFICATION & OSSIFICATION
as compared
to MRI

28. DIAGNOSTIC ULTRASOUND
High frequency sound waves by TRANSDUCER
penetrate into soft tissues
some waves are reflected back - registered as electric signals
and display images on a screen
• Image produce , depend upon reflective surface & soft tissue interface
• Different tissues display varying echogenicity
Fluid –filled cyst - echo free
fat - highly echogenic
semi solid organs – varying degree of echogenicity
• REAL TIME display gives dynamic image – more useful than static image

29. ULTRASOUND(US)
Ultrasound probes used in musculoskeletal imaging: from left to right 14 Hz Hockey stick 14 Hz linear, 9
Hz linear, 6 Hz curvilinear, 18 Hz linear probe
US of the shoulder demonstrating a full-thickness tear of the supraspinatus tendon (a and b) with
fluid (*) within the subacromial subdeltoid bursa (c)

30. CLINICAL APPLICATIONS
• Identify hidden cystic lesions – haematomas ,
abcesses , popliteal cysts & arterial aneurysms
• Detect intra- articular fluid , synovial effusions &
monitor ‘ irritable hip ‘
• Use to detect tendinitis & partial or complete tears
• For guiding needle placement in diagnostic &
therapeutic joint & soft – tissue injections
• Screening of newborn babies for CDH , catilaginous
femoral head & acetabulum

31. DOPPLER ULTRASOUND
• Blood flow detected – principle of change in sound
frequency – material moving – towards or away
from USG transducer
• Abnormal increased blood flow – areas of
inflammation / aggressive tumours
• Different flow rates – different colour
representations – colour doppler

32. RADIONUCLIDE IMAGING
• Photon emission by radionuclide taken by specific
tissues – recorded by gamma camera - reflects
physiological activity of that tissue
• Radiopharmaceutical used – 2 components
chemical compound – metaboloic uptake in
target tissue
radioisotope tracer – emit photons for
detection

33. ISOTOPE BONE SCAN
• Bone imaging - technetium – 99 m – ideal isotope
short half life – 6 hrs
rapidly excreted in urine
• Technetium – labelled hydroxymethylene
diphosphonate ( 99mTc-HDP) given intravenously &
recorded at 2 stages
1) Early perfusion phase - isotope in blood stream –
reflecting local
blood flow difference
2) Delayed bone phase – 3 hrs later – isotope in bone
tissue

35. • 4 types of abnormality seen
1) Increased activity in perfusion phase - inflammation , fracture ,
high
vascular tumour , regional sympathetic dystrophy
2) Decreased activity in perfusion phase – local vascular
insufficiency
3) Increased activity in the delayed bone phase – fracture , implant
loosening , infection , local tumour
4) Diminished activity in the bone phase - femoral head after
fracture in the femoral neck

36. CLINICAL APPLICATIONS
• Diagnosis of stress fracture /undisplaced fracture
• Detection of a small bone abcess or osteoid osteoma
• Investigation of loosening or infection around
prostheses
• Diagnosis of femoral head ischaemia in perthes’
disease or avascular necrosis in adults
• Early detection of bone metastasis

37. ADVANTAGE & DISADVANTAGE
• ADVANTAGE
whole body can be imaged for multiple sites of
pathology ( occult metastasis , multifocal infection )
provides physiological activity of examined tissues
• DISADVANTAGE
significant radiation burden
image yeilded make anatomic localization difficult

38. OTHER RADIONUCLIDE
COMPOUNDS
• GALLIUM - 67
concentrates in inflammatory cells – identify
hidden infection
• INDIUM – 111 – LABELLED LEUCOCYTES
distinguish sites of active infection from chronic
inflammation

39. SINGLE – PHOTON EMISSION
COMPUTED
TOMOGRAPHY ( SPECT )
• SPECT - bone scan – images are recorded &
displayed in all 3 orthogonal planes ( coronal ,
sagittal & axial plane )
spatial localization of pathology

40. POSITRON EMISSION TOMOGRAPHY
( PET )
• Positron – emitting isotopes - short half life – produced by cyclotron
• M/C used – 18 – fluro – 2 – deoxy – D – glucose ( 18 – FDG )
measures rate of consumption of glucose
• Malignant tumours metabolize glucose faster than benign tumours
• PET/CT – hybrid examination – superimpose the 2 image produced
• Use in ONCOLOGY to identify occult malignant tumours & distinguish
active residual tumour from inactive post – surgical scarring &
necrotic tumour .

41. BONE MINERAL DENSITOMETRY
• Bone mineral density measurement – widely used in
oseoporosis & increased risk of osteoporotic fractures
• Various techniques developed
RADIOGRAPHIC ABSORPTIOMETRY ( RA )
QUANTITATIVE COMPUTED TOMOGRAPHY ( QCT )
QUANTITATIVE ULTRASONOMETRY ( QUS )
DUAL ENERGY X- RAY ABSORPTIOMETRY ( DEXA ) – M/C
accepted

42. • RA - conventional radiographic equipment – bone density in
phalanges
• QCT – trabecular bone density in vertebral bodies
• QUS - measures bone mineral density in peripheral skeleton
( wrist & calcaneum )
• DEXA - columnated low – dose X ray beams to distinguish bone density from
soft tissue
• Advantage of DXA – develop huge international database – express bone mineral
density in comparison to age & sex matched population. (Z-score) and peak adult
bone mass (T score)
• According to WHO, T score <-1- osteopenia & T-score <-2.5 – osteoporosis.

44. RECENT UPDATES IN IMAGING

45. FLUOROSCOPY
• Fluoroscopy is an imaging technique that uses a continuous or pulsed
X-ray beam to obtain real-time, dynamic images.
• This imaging technique is a useful diagnostic tool for radiologists and
is used to guide interventional procedures such as needle placement
in joint and spinal injections, vertebroplasty and arthrography.
• Fluoroscopy is also used by orthopedic surgeons to guide
intraoperative prosthetic placement and to assess fracture
reduction.

46. CONTRAST-ENHANCED
ULTRASOUND(CEUS)
– A contrast agent containing gas microbubbles is injected intravenously
and enhances the Doppler signal.
– CEUS is more sensitive than conventional ultrasound in identifying active
synovitis as a marker for disease activity in arthritis.
– It may also be used to characterize soft-tissue lesions and assess the
vascularity of repaired rotator cuff tendons.

47. Extended Field of View (EFOV) US:-
– This is a useful tool in musculoskeletal imaging which allows for a
panoramic, continuous image of a soft-tissue structure to be obtained.
Superb Microvascular Imaging:-
– This technique has been developed to detect perfusion of tiny vessels
with slow flow without the need for intravenous contrast.
– It may also be used to stage progression of tendinosis in sports medicine
and can be used to monitor healing in chronic injuries such as tendinitis.
– It is useful diagnostic tool in carpal tunnel syndrome by detecting low-
flow blood flow in the median nerve.

48. US image of a soft-tissue lesion with intra-
lesional vascularity
(a) An US-guided biopsy was performed
(b) with the arrows outlining the biopsy
needle passing through the lesion.
Histology confirmed a soft-tissue sarcoma
contrast-enhanced ultrasound for
detection of synovial vascularity in
experimental rheumatoid arthritis

49. IMAGING MODALITIES
superb microvascular imaging ultrasonography in the
diagnosis of carpal tunnel syndrome

50. SONOELASTOGRAPHY
• Noninvasive, qualitative assessment of soft-tissue elasticity and
stiffness.
• The use of sonoelastography to identify Achilles, patellar, and
common extensor tendinopathy of the elbow have been
encouraging.
• Limitations include its reliance on skilled, repetitive manual
compression to obtain high-quality images.
.

51. SHEAR WAVE ELASTOGRAPHY
(SWE)
• SWE provides a quantitative assessment of tissue elasticity.
• This technique involves the transfer of an acoustic pulse from the
ultrasound probe into the target tissue.
• This produces a shear wave which extends laterally in the insonated
tissue.
• This technique has shown promise in assessing tendon , muscle, and
nerve disorders

52. ARTHROGRAPHY
• Arthrography is the introduction of a contrast agent (iodine or gadolinium)
into a joint space.
• This is performed under fluoroscopic guidance, which ensures correct
needle placement and intra-articular injection of contrast.
• It is in combination with CT or MRI allows for optimal visualization of the
internal joint structures.
• Dynamic assessment of joints following injection of contrast can also be
performed under fluoroscopic guidance.

53. IMAGING MODALITIES
• Fluoroscopy: AP fluoroscopic
views of the lumbar spine
during a vertebroplasty with
needles in situ (a) and
following introduction of
cement (b)
• AP Arthrogram of the
glenohumeral joint with
contrast in situ which was
introduced via a 22G needle

54. DUAL-ENERGY CT (DECT)
• DECT allows for the contemporaneous acquisition of images using two
different X-ray energies, and therefore showing different tissue
contrasts.
• DECT has a number of advantages over conventional CT;
– DECT can reduce artifact,
– Aid in image optimization, and
– Provide additional information on tissue composition.

55. Vertebral Compression Fracture with Bone Marrow
Edema

56. CONE BEAM CT(CBCT)
• CBCT allows for high spatial resolution assessment of bony architecture
at a lower radiation dose than conventional CT.
• CBCT can be combined with arthrography which allows for detailed
assessment of the articular cartilage, identification of intra-articular
loose bodies and synovial tumors/PVNS, and evaluation of
osteochondral defects.
• Limitations :-
– Small field of view
– Limited soft-tissue assessment.

57. CT- ARTHROGRAPHY
• CT arthrography involves the intra-articular injection of
iodine contrast under fluoroscopic guidance followed by a
CT of the region of interest.
• It can be used to assess the meniscus for a tear following
meniscal repair and has been shown to be superior to MR
arthrography in assessing the cartilage in the hip.

58. CT arthrogram of the knee showing tear of the anterior cruciate ligament (ACL) graft and trochlear cartilage erosion.
CT arthrogram of the knee showing a meniscal tear.

59. CT-GUIDED INTERVENTION
• CT is commonly used in the musculoskeletal setting to guide needle
placement in minimally invasive procedures such as steroid and
botulinum toxin injections, vertebroplasty, sacroplasty , and bone
biopsies.

60. CHEMICAL SHIFT IMAGING (CSI):
• It is used to differentiate between benign and malignant tumors
based on the premise that a lesion containing fat is highly suggestive
of a benign lesion.
• USES:-
– Benign fat-containing lesion can be differentiated from a malignant
lesion
– Benign pathological fractures may be differentiated from malignant
pathological fractures.

61. 45-year-old man, a known case of bronchogenic carcinoma, presented with back pain after
falling from height. Conventional and chemical shift MRI sequences revealed
benign vertebral compression confirmed with 6 month follow up negative MRI
study for marrow infiltration. Conventional MRI (A) sagittal T1-weighted spin-
echo (B) sagittal T2-weighted spin-echo and (C) sagittal STIR shows D12 vertebral
body compression with mild convex retropulsion and mild bone marrow edema.
Chemical shift MRI (D) in/phase (E) out/phase gradient-echo MR images show a
marked signal dropout of the compressed (arrows) as well as normal vertebral
marrow on out-of-phase image compared with in-phase

62. DIFFUSION PERFUSION IMAGING
• Used to evaluate
musculoskeletal tumors by
monitoring the early
enhancement of a tumor and
displaying the enhancement
pattern as a time-intensity
curve.
• Used to assess epiphyseal
perfusion and to exclude
avascular necrosis in the setting
of slipped upper femoral
epiphysis.

63. MR NEUROGRAPHY(MRN)
• Also known as MRI of peripheral
nerves.
• MRN can directly assess nerve
pathologies by detecting
abnormalities in nerve contour and
signal or indirectly by signs of
muscle denervation.
• It can be used to identify non-
discogenic sources of sciatica such
as distal nerve entrapment,
piriformis syndrome, ischial tunnel
syndrome, and nerve compression
from tumor.
High-Resolution MR Neurography of
the Brachial Plexus and Its Branches,
with Emphasis on 3D Imaging

64. Whole-Body MRI (WB MRI):
• WB MRI is used in the screening and staging of
hematological cancers such as multiple myeloma and
lymphoma.
• Also used to detect skeletal metastases in cancer staging.
• Also used to evaluate systemic arthritis such as
ankylosing spondylitis and psoriatic arthritis.
MR Arthrography (MRA):
• Fluoroscopic guided injection of gadolinium contrast prior to MRI
allows for joint distension and improved visualization of the internal
structures of the imaged joint.
• It is used in the assessment of labral injuries of the shoulder and the
hip.

65. Whole-Body MRI (WB
MRI):
• Staging WB MRI T1 (a) and STIR (b)coronal images
demonstrating multifocal Ewing’s sarcoma with lesions in
the bilateral femora and in the right humerus.
MR Arthrography
(MRA):
• MR arthrogram of the shoulder demonstrating a normal
labrum and intact glenohumeral articular cartilage

66. BONE SCINTIGRAPHY
• Bone scintigraphy is the most commonly performed SPE NM study in the
musculoskeletal setting.
• It uses technetium-99m labelled methylene diphosphonate (99mTcMDP) which
accumulates at sites of high bone turnover (osteoblastic activity).
• Clinical indications for bone scintigraphy :-
1. Identification of osteoblastic bone lesions/metastases,
2. Radiographically occult fractures,
3. Acute osteomyelitis,
4. Reflex sympathetic dystrophy,
5. Metabolic bone disease (for example, Paget’s disease), and
6. Evaluation of joint prostheses for infection or loosening.

67. NUCLEAR MEDICINE
White-Cell Scan:-
– Isotope-labelled white-cell scans can be performed using indium-
111 (111In) to assess for bone infection.
Single-Photon Emission Computed Tomography CT (SPECT-CT):-
– This technique is more accurate at identifying bone metastases than
standard bone scintigraphy or SPECT and decreases the number of
equivocal lesions by improving anatomic localization of uptake.

68. NUCLEAR MEDICINE
PET-CT:-
• PET-CT is a key imaging tool in the staging and treatment response monitoring
of oncology patients.
• It is most commonly used in the staging of non-sarcomatous malignancies and
lymphoma.
• It is also indicated for use in the initial staging of bone and soft-tissue
sarcomas and assessment of response to treatment.

69. PET-CT
• Non-oncological musculoskeletal
applications are
– Identifying sites of suspected
osteomyelitis in patients with
pyrexia of unknown origin,
– Evaluating knee and hip
prostheses for infection, and
– Differentiating insufficiency
fractures from pathological
fractures.
Coronal PET-CT image (a) demonstrating increased
uptake in the left tonsil in keeping with the patient’s
known tonsillar carcinoma. A focal area of increased
uptake was also noted at the inferior aspect of the
left glenoid rim (b). A biopsy was performed which
confirmed focal pigmented villonodular synovitis
(PVNS)

70. NUCLEAR MEDICINE(NM)
PET-MR:
– It is used in the staging of primary malignant bone soft-tissue
tumors due to its excellent soft-tissue resolution and reduced
ionizing radiation compared to PET-CT.

71. THANK YOU