Session 6: Pathological Fractures and introduction to Radiology

List some types of imaging

Ultrasound

X-ray

CT

MRI

Nuclear medicine (PET)

Ultrasound

Electricity turned into sound waves (vibration) which passes through structures. Electrical current causes crystal to vibrate – generating ultrasound waves

Application = monitor fetus growth in pregnancy

Pros/cons of ultrasound

Pros

- Good at viewing soft tissues and vessels

- Real-time imaging (dynamic)

- Portable machines (bedside)

- No radiation

- Useful in interventional radiology

- Quick, simple

Cons

- Limited penetration (excess body fat)

- Bone (poor detail)

- Dependent on skill of operator

X-rays are short wavelength electromagnetic radiation

What are the pros/cons of x-rays?

Pros

- Good at seeing air (black) and bones (white)

- Can be done rapidly

- Can be portable

- Low dose of radiation compared to CT scan

Cons

- Limited detail

- Difficult to see soft tissue

- Electromagnetic radiation exposure (albeit low)

- May still require further imaging to confirm a diagnosis, low sensitivity

- 2D image only

CT scans (computed tomography) are 3D x-rays (multiple x-rays pieced together in a software)

Pros/cons of 3D CT?

Pros

- 3D X-ray (multiple x-rays pieced together in software)

- Quick

- With or without contrast

- 3D reconstruction

Cons

- Radiation hazard

- Nephrotic contrast media

- Lower resolution than MRI

- Claustrophobia

In which anatomical plane is this CT scan of the head taken

Saggital, coronal, transverse?

Transverse/axial

In which anatomical plane is this CT scan of the abdomen taken

Saggital, coronal, transverse?

Coronal

MRI (Magnetic Resonance Imaging)

Pros/cons of MRI?

Pros

- Does not use radiation

- Very high resolution

- 3D imaging

- High sensitivity (excellent soft tissue differentiation)

- Multiplanar

- Provides full section imaging (compared to ultrasound which is limited by window)

Cons

- Cannot be used if people have magnetic metal implants (e.g., pacemakers)

- Slow/lengthy exam

- Expensive

- Complex mechanism

- Motion artefact, claustrophobia

Pros/cons of nuclear medicine

Pros

- Gives 3D view of the body combined with CT/MRI

- Shows function & structure

- Analyses areas where radio-tracer accumulates (e.g., cancerous cells metabolising faster than normal cells)

Cons

- Uses small amount of radioactive sources

- Expensive

What anatomical plane is this MRI scan of the head taken?

Saggital

What is a fracture

A break or crack in a bone

What is a pathological fracture

Normal (minor) stress placed on a bone breaks it due to it being weakened by disease

Morbidity

Refers to ill health in an individual and the levels of ill health in a population or group.

Mortality

The number of deaths in a population from a particular cause

Normal bone is made up of ___ and ___ phosphate

collagen and calcium phosphate

Osteoblasts ___ bone

build

Osteoclasts ___ bone

Osteoclasts cut/claw away bone

Calcium absorbed in the small intestine and kidney using vitamin ___

vitamin D

Calcium levels and osteoclast activity modulated by ___

PTH (parathyroid hormone)

What are some causes of weak bones in children

Bone cysts, rickets, osteogenesis imperfecta, infection, cancer

What are some causes of weak bones in adults

Osteoporosis, osteomalacia, Paget's disease, infection, cancer

What are bone cysts

Fluid filled spots inside bones which develop during growth of bones

These usually do not cause issues but can occasionally weaken bones enough to break

Rickets and osteomalacia are caused by...

Low vitamin D

Leading to reduced calcium absorption

Leading to impaired mineralisation of bone

In children - rickets and osteomalacia cause bones to…

Grow without mineralisation

In adults - rickets and osteomalacia cause…

Impaired bone remodelling

Soft/weak bones

What are other causes of weak bones?

Osteomyelitis

Osteogenesis imperfecta

Paget's disease

Cancer

Osteomyelitis

Infection - causes area of bone breakdown due to bacterial infection

Osteogenesis imperfecta

Autosomal dominant inherited condition - brittle bone disease

Paget's disease

High turnover of bone - leads to area of high and low density

Osteoporosis approximately affects ___% people at age 50 and almost ___% of people at 80

Osteoporosis approximately affects 2% of people at age 50 and almost 50% of people at 80

___ is the most common cause of pathological fractures

Osteoporosis

Osteoporosis mainly affects ___ bones

Osteoporosis mainly affects cancellous (spongy) bones

What is the effect of osteoporosis on the bone?

Deterioration in trabecular bone matrix

Reduction in bone mass

Risk factors of osteoporosis

ACCESS

- Age/alcohol

- Corticosteroid use (prednisolone)

- Calcium (low)

- Estrogen (low) - post-menopausal, women

- Smoking

- Sedentary lifestyle

Some risk factors of osteoporosis

Older age

F > M

Calcium deficiency

Smoking

Alcohol intake high

Sedentary lifestyle

What tools is used to assess risk of osteoporosis?

FRAX - tool that puts risk factors together to determine risk of osteoporosis. This calculates the risk of major osteoporotic fracture (MOF)

INPUT

- Sex

- Weight/height

- Previous fractures

- Currently smoking

- Glucocorticoids

- Rheumatoid arthritis

What tool is used if someone is at significant risk of osteoporosis (used to guide treatment)?

DEXA scan - bone density scanning through x-ray

___ have a higher peak bone mass

Men have a higher peak bone mass

What is a fragility fracture

A fracture resulting from a force that would not ordinarily result in fracture

Secondary to osteoporosis

What is a common site of fragility fracture?

- Hip and vertebrae

- Wrist fractures

Fragility fractures are fractures after a fall from ___ height

standing height

Wrist fracture (FOOSH)

Fall on outstretched hand

Hip fracture

What is management of osteoporosis?

- Calcium & Vitamin D supplements

- Bisphosphonates

- Acute management of any fractures

What are some preventative measures against osteoporosis?

Early identification and intervention for risk factors

- HRT, careful use of steroid prescribing (prednisolone)

- Cessation of smoking/alcohol

- Medication review

Falls prevention

- Strength training & physio

- Home assessment

What type of molecules are temporarily realigned by magnets of an MRI machine?

Water molecules

What colour is fluid on an USS (ultrasound scan)?

Black

What is the indications for x-ray?

- Imaging of the skeletal system

- Can be used for detecting some disease processes in soft tissues

Chest x-ray indications

Used for identifying lung pathologies

- Pneumonias

- Infections

- Heart failure

- Cancer

Abdominal x-ray indications

Used for identifying obstruction, free air from visceral perforation

What is the indications for ultrasound?

- Transthoracic imaging = heart, echocardiogram

- Trans-abdominal = review swelling/masses

- Foetal scans = monitor foetal growth

- Soft tissue swellings = cysts, lymph nodes

- Assist biopsies, needle placement in central line insertion

Doppler ultrasounds are used for

Looking for clots

What is the indications for CT?

- Acute trauma

- Head injury/initial imaging for stroke/haemorrhage

- Cancer staging

- Abdominal imaging e.g., acute appendicitis

- Facial bones

What is the indications for MRI?

- Neuroimaging = demyelinating disease, dementia, cerebrovascular disease

- Cardiovascular = myocardial ischeamia, myocarditis, cardiomyopathies

- MSK = spinal, soft tissue tumours

- GI = liver, pancreas, bile duct

- Angiography = stenosis, aneurysm

Contraindications of MRI (absolute and relative?

Absolute = some metal implants (e.g, aneurysm clips), pacemakers, some stents, cochlear implants

Relative (mostly due to contrast agent used) = pregnancy, allergies, kidney disease

What does x-rays image?

Bone

What does ultrasounds image?

Soft tissues/vessels

What does CT scans image?

- Bones

- Soft tissue

- Calcium containing deposits

- Blood vessels (angiography)

What does MRI image?

Most tissues visualised well

High calcium and alkaline phosphatase (ALP) enzyme in blood test

Bone cancer