3. Radiology Of MSK Flashcards
Parts of musculoskeletal system
- Bones
- Soft tissue
- Cartilage
- Muscle
- Ligaments
- tendons
Examples of damage to tissues
- Break/tear
- Chronic wear and tear/ degernate
- Infection
- Primary cancer or metastases
Factors which determine which Imaging Modality to use
- Type of tissue
- Suspected injury- from clinical history
- Age/radiation exposure
- Previous imaging
Xray basic process
X ray source at one side of patient – detector on other side
• X rays travel through patient to hit detector
• X rays reach detctor = black
• X rays hit something dense = deflected x rays = white
Xray radiograph
Radiograph is a projectional image generated by passage of x-rays through an object (Patient in case of medial radiograph).
Image is generated on a detector plate called x-ray detector.
Detector plate is like a photographic film, when x-rays hit the plate, it turns black.
Amount of blackness depends on the number of x-rays hitting the plate. X-rays travel in straight line.
X-rays are stopped by materials with lot of electrons/dense materials like bones, metals etc.
Advantages of xrays
- X-rays are quick.
* X-rays are readily available and inexpensive.
Disadvantages of xrays
- Involves radiation.
- 2D Image to look at 3d structure
- Poor soft tissue information.
Uses of xrays in msk
Skeletal trauma/ acute bone or joint injury
- fractures
- joint dislocation
Evaluation of chronic bone or joint pathologies
- chronic osteomyelitis
- chronic joint arthritis
- chronic septic arthritis
CT scan
CT scan Computed tomography (CT) scanning, also known as computerised axial tomography (CAT)scanning, is a diagnostic imaging procedure that uses radiation to build cross-sectional images (“slices”) of the body CT scan provides thin sections of the musculoskeletal system.
CT scan images
Thin slices give detailed information about the bone structure and pathology. Soft tissue detail is better than plain radiographs.
Whole body CT can be performed in short time (few minutes) to look for bone or soft tissue injury. Subtle un-displaced fractures are better seen on CT scan.
Spinal fractures and other complex fractures like pelvic fractures are seen in great detail. Slices can be reformatted to give 3D construction. - used in surgery
CT scan advantages
Cross-sectional. Thin slices of the body.
Excellent in assessment of complex bone trauma.
Fast.
Multiplaner and 3D reconstruction.
CT disadvantages
Involves significant radiation.
Poor soft tissue detail (better than Plain radiograph)
MRI
Non invasive method of mapping the internal structures of the body.
Utilizes magnetic resonance of the hydrogen nuclei to produce high quality cross-sectional images of the body in any plane.
There is no use of ionising radiation.
It utilizes radio frequency waves in presence of carefully controlled magnetic field.
MRI
Two fundamental objectives
- Definition of normal anatomy
* Detection of pathology (Abnormal fluid/ enhancement)
Uses of MRI
—> MRI is used for assessment of bones, joints and associated soft tissue like ligaments and tendons.
• MRI is better than CT and X-ray in assessment of the soft tissue.
• MRI is used in assessment of MSK infection like osteomyelitis, soft tissue infection and septic arthritis.
• MRI is poor in showing micro-structure of the bone.