L05 – Introduction to Radiology of the Musculoskeletal System Flashcards
What are the soft tissues in a typical joint?
Muscle
Tendon
Ligament
Bursa
What are the advantages of radiography?
Readily available
Cheap and fast
Good bone and joint details especially for appendicular skeleton
What are the disadvantages of radiography?
Ionizing radiation
Limited soft tissue visualisation and differentiation
Not so good for complex anatomy or pathology
What are the applications of radiographic visualization in MSS?
1) Fracture
2) Bone tumors: Classification and diagnosis
3) Infection or inflammation i.e. osteomyelitis
4) Spinal column pathology: gross morphology i.e. degenerative scoliosis
Explain how CT scans work?
Combines continuous gantry rotation with table motion
» path of X-ray beam around patient follows a helical path
» Data acquired in single slice / single volume
Multi-slice helical scans produce a set of interleaved helices for reconstruction
Difference between helical CT scanning and Multi-slice helical reconstruction?
Helical scanning = one source, one detector
Multi-slice = increased detail and resolution using multiple sources and detectors
What are the advances in CT technology?
Faster scanning time for faster anatomical coverage
Higher resolution and finer detail
Software advances to improve image quality and 3D reconstruction
Advantages of CT in viewing MSS?
- Excellent for complex bone details
- Detects subtle soft tissue calcification
- Allow reconstruction into different planes (e.g. saggital, coronal)
- guide aspiration/ biopsy in deep tissue
Disadvantages of CT in viewing MSS?
Ionizing radiation higher
Quite expensive
Not as good as MRI and ultrasound for soft tissues differentiation
When is CT used to view MSS?
- Trauma with complex anatomy (i.e. pelvus, foot)
- Fast investigation in severe trauma with widespread damage
- High definition of bony details and calcification in tumours
- Deep seated abscess due to infection
- Guide nerve root block
What is HRUS used for visualizing?
High Resolution Ultrasound(HRUS)
For viewing superficial soft tissue details
Advantages of HRUS?
- No ionizing radiation
- Inexpensive
- Good for soft tissue details in superficial structures, masses
- Excellent spatial resolution particularly in superficial joints
- Real-time examination
- Available (+++), convenient
Disadvantages of HRUS?
- Operator dependent
- Long learning curve
- Limited depth of penetration of sound beam = poor delineation of large or deep masses/ cannot see through bone
When is HRUS used?
Confirm mass
superficial soft tissue pathology
Real-time examination of joints and tendons
Real-time guidance for aspiration or biopsy
What superficial soft tissue pathologies can HRUS help delineate?
- Cystic (hypoechoic/dark) or Non- cystic (hyperechoic/ light) masses
- Effusion vs Synovial thickening
- Dx of neurogenic tumour, lipoma
What is the imaging sequences of MRI?
1) T1- weighted: view Bone and Fat
2) Proton-density with fat suppression: view Cartilage and ligament
3) T2- weighted with fat suppression: view fluid retention/ edema, malignancies
Advantages of MRI in viewing MSS?
NO radiation multiplanar capability excellent soft tissue differentiation sensitive to bone marrow changes (similar to nuclear scan) spinal and epidural lesions
Disadvantages of MRI in viewing MSS?
Not readily available
Very expensive
Contraindicated in patient with pacemaker or electronic devices
What type of trauma needs MRI for viewing?
spinal and epidural lesions***
soft tissue or ligamentous injuries e.g. knee, shoulder, ankle***
trabecular fracture
Why is MRI needed for viewing tumors?
staging (not for diagnosis, cannot differentiate subtypes)
choosing biopsy site (MRI should be performed before biopsy)
Give examples of MSS infections that MRI can visualize?
osteomyelitis, myositis, arthritis (also seen with HRUS), tenosynovitis (also seen with HRUS), cellulitis
Give examples of spinal column and canal pathologies viewed by MRI.
Modality of choice for spinal and epidural lesions:
Intervertebral disc protrusion
Spondylodiscitis (paraspinal soft tissues)
Spinal cord / nerve (root) compression (e.g. metastasis from thyroid cancer)
Give an example of a radionuclide or nuclear scan?
PET
Positron emission tomography
When is radionuclide or nuclear scan used in viewing MSS?
- BONE METASTASIS scan: very sensitive for marrow changes but not specific (i.e. tumour and fracture may look similar)
- Specaliszed scans (e.g. WBC / gallium scan) for LOCALIZE ABSCESS/ INFECTION e.g. Acute Osteomyelitis)
Advantages of Nuclear scans in viewing MSS?
- Gives FUNCTIONAL INFORMATION
- EARLY DETECTION of disease e.g. tumour, infection
- Specific radionuclide for diseases e.g. abscess
Disadvantages of Nuclear scans for viewing MSS?
- Poor STRUCTURAL info.
- Not specific i.e. tumour, infection and fracture may look similar on bone scan
- EXPENSIVE
- IONIZING RADIATION
Choose the appropriate radiography method for: Simple fracture?
Xray
Choose the appropriate radiography method for: Patient with severe trauma and widespread damage?
CT
- Minimal mobilization of patient
- Fast and one-stop images for multiple system
- Prioritize management e.g. vascular injury
Choose the appropriate radiography method for: complex fracture of the foot?
CT
For regions having complex anatomy
Choose the appropriate radiography method for: cervical spine injury?
CT
Excellent for excluding cervical spine injury especially when radiographs are equivocal or inadequate
Choose the appropriate radiography method for: injured ligaments and soft tissue?
MRI
Choose the appropriate radiography method for: Spinal trauma with cord or neural damage?
MRI
Choose the appropriate radiography method for: Marrow edema?
MRI
Choose the appropriate radiography method for: vertebral anomaly in scoliosis?
CT
Choose the appropriate radiography method for: herniated intervertebral disc?
MRI
Choose the appropriate radiography method for: Paraspinal soft tissue damage?
MRI
Choose the appropriate radiography method for: effusion, synovial thickening, masses?
Ultrasound
Choose the appropriate radiography method for: deep soft tissue and intra-articular tissue damage?
MRI
What are the scans used to Dx and used when treating Rheumatoid arthritis?
Dx = X-ray
Guide injection of steroids into joint to treat inflammation = Ultrasound