The document outlines various imaging modalities essential for diagnosing orthopedic conditions, starting from X-rays discovered in 1895 to advanced techniques like MRI and CT. It discusses the characteristics, benefits, and limitations of each imaging method, including sensitivity, specificity, and the types of tissue evaluated. Furthermore, it highlights specific applications for imaging in assessing injuries, fractures, and joint diseases, while also addressing safety concerns related to ionizing radiation.

2.  Imaging modalities remains a keystone in
diagnosing orthopaedic conditions.
 Imaging started with the discovery of X-rays by W.
Rontgen in 1895.
 In general, imaging test have a high sensitivity –
few false negatives, but low specificity – high false
positive rate.

3.  Plain X-ray.
 Contrast Radiograph.
 Ultrasonography.
 Computed tomography.
 Magnetic Resonance Imaging.
 Scintigraphy.
 SPECT.
 PET

4.  High energy electromagnetic waves.
 Wavelength shorter than visible light.
 Structure –
◦ Positive anode
◦ Negative cathode
◦ Vacuum tube.
 Denser the tissue, greater X ray attenuation, more
bright.
 Commonly the first line investigation.

5.  Rule of 2 –
◦ 2 orthogonal views
◦ 2 joints.
◦ 2 sides
◦ 2 occasions
◦ 2 abnormalities
◦ 2 opinion.
 PACS - This is the system whereby all digitally
coded images are filed, stored.

6.  A convenient sequence for examination is: the patient –
the soft tissues – the bones – the joints.
 The patient –
◦ Identity,
◦ history and
◦ clinical findings.
 The soft tissues –
◦ Generalized change,
◦ Localized change.

7.  The bones –
◦ Shape
◦ Generalized change – density, sclerotic or lytic.
◦ Localized change - lesion’s size, site, shape, density.
 The joints - The radiographic ‘joint’ consists of the
articulating bones and the ‘space’ between them.
◦ The joint space.
◦ Shape.
◦ Erosions.

8.  Narrowing of the joint space +
subchondral sclerosis and cysts
+ osteophytes = osteoarthritis.
 Narrowing of the joint space +
osteoporosis + periarticular
erosions = inflammatory
arthritis

9.  Fracture/ Dislocation/ Subluxation.
 Soft tissue shadows.
 Evaluation of implants.
 Guiding image in case of close reduction.
 Identifying infection and tumours.

10.  Exposure of the patient to ionizing radiation.
 As a diagnostic tool, conventional radiography
provides poor soft-tissue contrast: for example, it
cannot distinguish between muscles, tendons,
ligaments and hyaline cartilage.

11.  The contrast media used in orthopaedics are
mostly iodine-based liquids which can be injected
into sinuses, joint cavities or the spinal theca.
 Ionic, water-soluble iodides permit much more
detailed imaging and, although also somewhat
irritant and neurotoxic, are rapidly absorbed and
excreted.

12.  Sinography –
 Arthrography – Intra-articular loose bodies will
produce filling defects in the opaque contrast
medium.
 Myelography -

13.  Introduction - The frequency used for therapeutic
ultrasound is usually 0.5 MHz (LIPUS) while those for
diagnostic ultrasound range between 2 MHz and 10
MHz.
 Higher the frequency used, the greater the spatial
resolution.
 Higher frequency probes (5 MHz–7.5 MHz) -
 Lower frequency probes(3–5 MHz).

14.  “A” (amplitude) type scanning –
 “B” (brightness) type scanning –
 Hypoechoic – Fat, Hyaline cartilage,
Synovium/capsule, Nerve.
 Hyperechoic – Tendon, Muscle, Fascia,
Ligament, Bone/periosteum.

15.  Advantages of ultrasonography –
1. Safety is the foremost advantage.
2. Real time imaging capability allowing dynamic
evaluation
3. Low cost
4. Easy accessibility
5. Portability
6. Non invasiveness
7. Multiplanar imaging.

16.  Diagnostic –
◦ Tendons –
 Tears
 Tendinosis, tendinitis and tenosynovitis
 Peritendinitis.
◦ Cysts –
 Therapeutic -
o Enthesopathy
o Bursitis
o Postoperative
o Interventional
o Aspiration of cysts, abscess and hematoma, etc.
o Injection of sclerosant into cysts.

17.  Plain tomography –
 Like plain tomography, CT produces sectional
images through selected tissue planes – but with
much greater resolution.
 The images are trans-axial.
 Region of interest is selected and a series of cross-
sectional images is produced and digitally
recorded.

18.  Clinical applications - CT achieves excellent
contrast resolution and spatial localization, it is
able to display the size, shape and position of
bone and soft-tissue masses in transverse planes.
 Image acquisition is extremely fast.

19.  It is routinely used for assessing injuries of the
vertebrae, complex fractures and fracture-
dislocations at any site.
X-ray - fracture of the calcaneum
CT sagittal view

20.  Limitations - it provides relatively poor soft-
tissue contrast when compared with MRI.
 A major disadvantage of this technique is the
relatively high radiation exposure to which the
patient is subjected.

21.  Introduction - Magnetic resonance imaging
produces cross-sectional images of any body part
in any plane. It yields superb soft-tissue contrast,
allowing different soft tissues to be clearly
distinguished, e.g. ligaments, tendons, muscle and
hyaline cartilage.

22.  MRI physics – Different speeds of tissue excitation
with radiofrequency pulses (repetition times, or
TR) and different intervals between recording
these signals (time to echo, or TE) will yield
anatomical pictures with varying ‘weighting’ and
characteristics.

23.  T1 weighted Image - high spatial resolution and
provide good anatomical- looking pictures.
 Short TR ( <1000) and TE (around 10).
 Fat Bright and Fluid dark.

24.  T2 weighted (T2W) images - give more information
about the physiological characteristics of the
tissue.
 Long TR (around 4000) and TE (around 90).
 Fat Dark and Fluid Bright.

25.  Proton density (PD) images - ‘balanced’ or
‘intermediate’.
 Yield excellent anatomical detail for orthopaedic
imaging.
 Medium TR and Medium TE.
 Fat bright (Dark if PDFS) , Fluid also bright and
Muscle medium.

26.  Fast spin-echo technique - This reduces length of
T2 sequence by two-thirds. But this produces
some blurring artifact.
 Gradient-echo technique – Fat Dark, Muscle Dark
and fluid Dark.
 Used selectively for cartilage imaging.

27.  Knee –
◦ Meniscal tears
◦ Degenerative conditions of meniscus
◦ Ligament tears
◦ Patellar or quadriceps tendon tears
◦ Tendinitis
◦ Cysts
◦ Synovial pathology
◦ Occult fractures
◦ Popliteal mass
◦ Physeal injuries in children.

30.  Shoulder –
◦ Rotator cuff tear
◦ Impingement syndromes
◦ Instability
◦ Osteonecrosis
◦ Pathological conditions of the tendon
 Spine –
◦ Evaluation of intervertebral disk disease
◦ Discitis
◦ Pyogenic and tuberculous infections

33.  Foot and ankle –
◦ Tendinopathy
◦ Articular disorders
◦ Osseous pathological conditions
◦ Avascular necrosis
◦ Fracture
◦ Osteochondral injuries
◦ Osteomyelitis
◦ Tendon injury
◦ Ligament injury.
 Hip –
◦ Avascular necrosis
◦ Transient osteoporosis of the hip
◦ Occult fractures

34. • Presence of intracerebral aneurysm clips
• Implanted cardiac pacemakers and automatic defibrillators
• Bio stimulators
• Implanted infusion devices and internal hearing aids
• Metallic orbital foreign bodies
• Metal external fixation devices
• Cochlear implants
• Ferromagnetic foreign bodies like shell shrapnel.
First-trimester pregnancy