Abdominal imaging - masterclass Flashcards
What is diffuse abdominal pain?
Pain occurring throughout the whole abdominal area.
Some causes of diffuse abdominal pain?
Acute pancreatitis
Diabetic ketoacidosis
Mesenteric ischaemia (a blockage in an artery cuts off blood flow to a portion of the intestine).
Causes of left upper quadrant pain?
Splenic disorders (ruptures, abscesses)
Gastritis (inflammation of stomach lining).
Causes of right upper quadrant pain?
Perforated duodenal ulcer
Hepatitis or hepatic abscess
Causes of left lower quadrant pain?
Sigmoid diverticulitis
Causes of right lower quadrant pain?
Appendicitis
Meckel’s diverticulitis
Mesenteric adenitis
Causes of both right or left upper quadrant pain?
Acute pancreatitis
Herpes zoster
Lower lobe pneumonia
Causes of both right or left lower quadrant pain?
Abdominal or psoas abscess
IBD
Renal stone
Ruptured abdominal aortic aneurysm
Primary imaging tools of the abdomen?
X-ray
CT
USS (ultrasound scan)
Secondary imaging tools of the abdomen?
MRI
(Fluoroscopy)
Pros of x-ray?
Widely available
Supine AXR - Assessing for bowel obstruction
Erect CXR - Assessing for hollow viscus perforation
Quick
Well Tolerated
Inexpensive
Cons of x-ray?
Overall sensitivity low
Rarely changes management
Ionising radiation
Pros of ultrasound scan?
Easy, safe (no ionising radation)
Clear visualization of solid organs, free fluid, aorta, female pelvic organs
Bowel – occasionally helpful
Correlate imaging with tenderness
Cons of ultrasound scan?
Operator and patient dependant
Challenging in obese and/or immobile patients
Pros of CT scan?
Quick
Relatively widely available and tolerated
Accurate
Sensitivity CT vs USS – 89% vs 70%
Allows multiple structures to be imaged simultaneously
Allows better planning of surgery or intervention
Cons of CT scan?
Radiation exposure – risk of complications increases as the dose increases.
Contrast induced nephropathy
Contrast allergy
What is MRI used as second line for?
Hepato-Biliary
Small bowel
pelvis
Where does acute appendicitis pain present?
RIF (right iliac fossa)
X-ray can be used for acute appendicitis. true/false?
False
CT and USS are important tools
Confirm Diagnosis
Detect alternative pathologies
Ideally, use USS first, then CT if this is inconclusive
No role for x-ray in this
Appearance of acute appendicitis in USS?
target appearance (axial section)
peri appendiceal fluid collection
Appearance of acute appendicitis in CT?
appendiceal dilatation (>6 mm diameter)
wall thickening (>3 mm) and enhancement
Pain associated with right ureteric calculus?
Right “loin to groin” pain
What is gold standard for ureteric stone imaging?
Non-contrast CT (CT KUB) is the gold standard for imaging ureteric stones, with the vast majority (99%) being radiodense
Stones more >1mm are visualised. true/false?
True
Show up on non-contrast CT
Where does acute diverticulitis pain present?
LIF (left iliac fossa)
Who is most likely to get acute diverticulitis?
elderly patients most at risk
80% of 80-year-olds have diverticula
4% go on to develop diverticulosis
Presentation of acute diverticulitis?
left iliac fossa pain
unremitting pain with associated tenderness
possibly, an ill-defined mass
as the disease progresses, symptoms become more generalised
Investigation of choice for acute diverticulitis?
CT with IV contrast
CXR can possibly look for perforation
Reasons for imaging in acute diverticulitis?
confirmation of diverticula
confirmation of active inflammation around diverticula
assess for complications, e.g. perforation, abscess
look specifically for fistula, e.g. with bladder
identify other potential causes of symptoms
How to tell which way a CT or MRI scan is done?
Radiologists view CT and MR as if they are looking from the feet upward (the right image is the left side of the patient).
4 main potential diagnoses for epigastric and RUQ pain?
Biliary colic
Cholecystitis
Pancreatitis
Perforation
Acute Cholecystitis (gallbladder inflammation) is always secondary to gallstones. true/false?
True
Almost always CTs ordered should be ordered “with” OR “without’ only – NOT BOTH. true/false?
True
When is contrast CT used?
CT of the abdomen and pelvis (with the exception of a CT stone study and CT angiography) will receive an oral contrast prep.
So non-contrast CT is only used usually used for CT of ureteric stones and CT angiography (lymph or blood vessels).
What common indications do not require use of IV contrast?
flank pain
evaluating for urinary tract calculus hernia
When should CT contrast be used?
Abdomen pain
Pancreatitis
Painless jaundice
Abdominal mass
To rule out Small Bowel Obstruction
Staging Colorectal Carcinoma
To assess vascular pathology
Assess for abscess
Oral CT contrast vs IV CT contrast?
IV contrast improves tissue contrast, the parameter that distinguishes one organ from the next) and greatly aids in identifying masses or inflammatory/infectious processes.
oral contrast is used for most abdominal and pelvic CT scans unless there is no suspicion of bowel pathology
