2 - General and T&O Imaging Flashcards
What are the different types of imaging that can be done for abdominal pathology and what are they used for?
AXR: suspected bowel obstruction, suspected perforation (erect CXR), moderate to severe undifferentiated abdominal pain, suspect foreign body, renal tract calculi follow up
CT: abdominal trauma, suspected intra-abdominal collection, malignancy
US: RUQ
Endoscopy: acute upper GI bleed
How should you present any x-ray in general?
How should you read an abdominal x-ray?
AbdoX
A: air - where it should and should not be- Should only be in the lumen, erect x rays are more sensitive
B: bowel - position, size and wall thickness- 3-6-9 rule
D: dense structures, calcification and bones- calcified renal tract/ gallstones
O: organs and soft tissues- remember lung bases
X: eXternal objects and artifacts
How should you read a CXR?
Assess image quality RIPE
R- Rotation- The medial aspect of each clavicle should be equidistant from the spinous processes. The spinous processes should also be in vertically orientated against the vertebral bodies
I- Inspiration- The 5-6 anterior ribs, lung apices, both costophrenic angles and the lateral rib edges should be visible.
P- Projection- Note if the film is AP or PA: if there is no label, then assume it’s a PA film (if the scapulae are not projected within the chest, it’s PA).
E- Exposure- The left hemidiaphragm should be visible to the spine and the vertebrae should be visible behind the heart.
How can you tell the difference between small and large bowel on an AXR?
- In ascites bowel loops are clustered centrally
- 3/6/9 rule
- Thumbprinting when large bowel inflammation
What are some of the causes of pneumoperitoneum and what would you see on imaging this?
Erect CXR: free air under diaphragm, leaping dolphin sign, cupola sign when supine, continuous diaphragm sign
AXR: Rigler sign, Telltale triangle sign
What is Rigler’s sign?
Double wall sign where gas is on both sides of the bowel forming crisp line on bowel that you could draw around.
Sign of pneumoperitoneum
What are the aims of imaging in a bowel obstruction?
- differentiate true mechanical obstruction from ileus or constipation
- find site of obstruction
- identify cause
- assess for complications (e.g. ischaemia or perforation)
- assess the viability of bowel segments involved
What would you find on imaging a bowel obstruction?
AXR:
- Dilated bowel loops 3/6/9
- Perforation
- String of Pearl’s sign
CT:
- Transition point
- Collapsed or normal bowel past transition but dilated before
- Bowel wall thickening
- Surrounding mesenteric fat if inflammation
- Volvulus
What does this AXR show and why does this occur?
Thumbprinting
Sign of large bowel wall thickening usually due to oedema. Haustra become thickened
Causes: UC, Crohn’s, Infection, diverticulutis, lymphoma
What would you use when imaging urolithiasis?
CT KUB non-contrast is gold standard
How can you tell the difference between a sigmoid and caecal volvulus and what are the different aetiologies of these two pathologies?
Sigmoid: chronic constipation, colonic distension, elderly, bed bounds
Caecal: congenital long mesentry, congenital malrotation, congential defect in fixation of the right colon to peritoneum
What does this CT show around the kidney and what does this indicate?
Fat stranding which shows inflammation
What is Rigler’s triad?
Sign of gallstone ileus
- pneumobilia
- small bowel obstruction
- ectopic calcified gallstone, usually in the right iliac fossa
What are the main causes of small and large bowel obstruction?
How does a CT abdomen scan work and what are the advantages and disadvantages of this imaging?
- check renal function
- lie patient supine on CT table
- scout image to plan study
- IV contrast injected via pump-injector
- 60-second delay
- scan from dome of diaphragms to symphysis pubis
What should you look for on a CT with a bowel obstruction?
- Find obstruction
- Find dilated loops before obstruction
- Find collapsed area after obstruction
What are some of the different phases than can be used in CT?
- Non contrast: CT KUB for renal stones or allergic to contrast
- Systemic arterial (35 seconds): vascular imaging can made 3D angiogram
- Portal venous (70 seconds): intravenous contrast, good for acute abdomen imaging and outpatients
- Delayed (depends): urological imaging takes 7-10 minutes
Systemic arterial and portal venous together can see bleeding
When is contrast for CT given orally and through the bladder?
- Orally: to look for leaks and fistulas in the upper GI
- Foley catheter: after pelvic trauma to determine if bladder rupture (extra/intra peritoneal rupture)
How long does contrast take to get to different vessels in the body?
When should you avoid enteric contrast for CT?
Enteric contrast, such as oral or rectal contrast agents used to enhance visualization of the gastrointestinal tract in CT imaging, should be avoided in certain situations, including:
- Known or suspected gastrointestinal perforation: The use of enteric contrast can exacerbate peritoneal irritation and potentially lead to peritonitis if there is a pre-existing gastrointestinal perforation.
- Impaired swallowing or risk of aspiration: Patients who are unable to swallow safely or are at risk of aspiration should not be given oral contrast agents to avoid the risk of aspiration pneumonia.
- Severe dehydration or electrolyte imbalances: In patients with severe dehydration or electrolyte imbalances, the administration of enteric contrast may further compromise fluid and electrolyte balance.
- History of severe allergic reactions to contrast agents: Although enteric contrast agents are generally safe and not absorbed systemically, patients with a history of severe allergic reactions to contrast agents may prefer to avoid them altogether.
- Known intolerance or contraindication to specific enteric contrast agents: Some patients may have specific intolerances or contraindications to certain types of enteric contrast agents, such as iodine-based agents, and alternative agents should be used in these cases.
Always assess the patient’s clinical history and consider the potential risks and benefits before administering enteric contrast for CT imaging. In some cases, alternative imaging modalities or non-contrast CT scans may be more appropriate.
When requesting x-rays for MSK, what do you need to consider?
- Which structures?
- Which views? (two views 90 degrees apart)
- Compare both sides and review previous images
- Correlation with clinical and other imaging findings
How do you review an MSK x-ray?
- Name, Age, Date and Time of X-rays
- What is being imaged and the most obvious abnormality
- Is the image quality and angles satisfactory?
- See image (Bones, Soft tissue, Joint, Anything else)
How do you describe a fracture on an x-ray?
- What type of fracture (oblique, transverse etc)
- Where is the fracture (diaphysis, metaphysis, epiphysis)
- Is it displaced (rotation, translation, angulation, length)
- Say where the distal frament is compared to proximal (e.g displaced anteriorly and medially)
- Anything else? (joint involvement, bone lesions, anothe fracture)
How do fractures and dislocations appear on radiographs?
Fractures: dark line, white line (bone on bone), irregularity in the cortex
Dislocation: irregular soft tissue, change in joint space
Always look for sclerotic, lytic, mixed bone lesions
How do you describe the length of a bone on a radiograph?
- Normal
- Impacted (shortened)
- Distracted (longer)
How does a bone cyst, a metastatic bone deposit and multiple myeloma appear on x-ray?
Bone cysts: (see image) lytic lesion with sclerotic border
Metastases: irregular sclerotic or lytic (more common) lesions
Multiple myeloma: numerous, well-circumscribed, lytic bone lesions/pepperpot skull/general osteopenia
How do you describe fracture angulation on an x-ray?
- Draw lines where bone should be and use distal fragment to describe or use apex of deformity (opposite)
- Can use words dorsal/palmar, varus/valgus, radial/ulnar
What does this x-ray of the shoulder show?
LIGHT BULB SIGN
Internal rotation of shoulder OR Posterior Dislocation
What does this x-ray of the shoulder show?
Anterior dislocation (learn radiographic findings)
May see a Hill Sachs lesion if externally rotate shoulder
What is the pathology on this shoulder radiograph?
What is the pathology on this x-ray?
Fallen fragment sign
Sign of a pathological fracture. Bone cysts with linear areas within them
What is the pathology of this x-ray?
Can see fat pads (prominent anterior) so large elbow joint effusion
What is the terrible triad?
Posterior elbow dislocation
Radial head fracture
Coronoid process fracture
What is the pathology on this x-ray?
Radial head dislocation (radius not in line with capitulum, radiocapitullar line)
What is the pathophysiology on this x-ray?
Supracondylar fracture
Raised fat pad, abnormal anterior humeral line, normal radiocapitellar line
What is the pathology on this x-ray?
What is the pathology on this x-ray?
MU vs GR
Man united versus Rangers
What is the pathology on this x-ray?
NO INTRARTICULAR EXTENSION
What is the pathology of this x-ray?
Volar displacement and no intrarticular extension
What is the pathology on this x-ray?
Radial styloid fracture with scapholunate dissocation
Will result in OA if not picked up and ligament repair! Can’t just cast
What is the pathology on this x-ray?
What can you see on x-ray with early avascular necrosis of the scaphoid?
Early sclerosis of proximal pole of scaphoid
What is the pathology on this x-ray?
Triquetral fracture (can only see on lateral)
What is the pathology on this x-ray?
5th Metacarpal dislocation
What is the pathology on this x-ray?
Fracture of the base of the first metacarpal due to forced abduction of the thumb. Intrarticular fracture
If comminuted into at least 3 it is called a Rolando fracture
Often needs emergency surgery
What is the pathology on this x-ray?
Boxers fracture (fracture of 5th metacarpal)
A patient who recently had abdominal surgery develops this (see image). What is the likely causative organism and how should this patient be managed if they have no signs of systemic infection?
Wound dehiscence due to E.Coli
Dehiscence is a partial or total separation of previously approximated wound edges, due to a failure of proper wound healing
Negative pressure VAC therapy
What are the 5 different ASA grades? (a grading system to determine the health of a person before a surgical procedure that requires anesthesia.)
COPD with home oxygen therapy that is housebound is grade 4
How do you work out a man and woman’s circulating blood volume quickly?
Gilcher’s Rule Of Five
Weight (kg) x Average Blood ml per kg
Man: usually 70ml/kg
Woman: usually 65 ml/kg
What antibiotics are used for acute prostatis and epididymo-orchitis?
Apart from U+Es, what further blood tests should you do?
- CRP and ESR
- LFTs
- Bone profile/Ca level
LOOKING FOR METS
Why does this patient have a left sided varicocele?
Left gonadal vein drains into left renal vein.
Tumour may thrombose and this occludes the left gonadal vein causing a varicocele
What is the medial clear space and what is the upper limit for this?
Space between the medial mallelous and the medial side of the talus
5mm
How do you treat a Weber B fracture?
Put in a below knee back slab for 1 week then bring back and x-ray before putting full cast on
