diagnostic imaging Flashcards
Presenting an image considerations
details: name, DoB, weight (+C contrast).
Type, mode. technical quality.
obvious abnormalities, lines, leads or tubes. , asymmetry.
differential diagnosis.
X-Ray presenting terminology
radiodensity.
US presenting terminology
echogenicity.
CT presenting terminology
attenuation.
MRI presenting terminology
signal intensity.
four cardinal elements of CXR
bone, air fat and water (Soft tissue).
technical aspects of a CXR
rotation: sternal ends of clavicles should be symmetrical overlie the 4/5th thoracic vertebrae.
inspiration: 5-7 ribs visible.
Exposure: definition of image
position: lung margin should be visible.
CXR nodules differentials to consider
neoplasia (metastatic), septic emboli, abscess, granulomas, sarcoidosis , pneumoconiosis
reticular opacification on a CXR refers to
lung parenchymal changes.
reticular opacification CXR differentials
acute interstitial oedema, infection, fibrosis, malignancy
alveolar opacification CXR differentials
pus, blood, water, cells or protein.
ring opacities CXR differentials
abscess, tumour or pulmonary infarct (wedge shaped)
linear opacities CXR differentials
Septal lines, pleural plaques (asbestosis)
SVC begins at
right 1st anterior intercostal space
right atrium lies at the level of the
3rd intercostal space
the carina should be visible at the level of
T5-T7 thoracic vertebrae
the right atrial appendage sits at the level of
the 3rd intercostal space
indications for an AXR
obstruction or intussusception, acute flare of IBD, renal colic with stones, ingestion of foreign body.
AXR thumb printing seen in
large bowel ischaemia and colitis - protrusion of thickened mural folds into lumen.
AXR coffee bean sign seen in
sigmoid and caecal volvulae - grossly dilates segments of bowel
small bowel gas patterns
smaller calibre, smaller central loops, folds that go from wall to wall, grey
large bowel gas patterns
larger, peripheral, semi lunar folds, blacker
ileus gas pattern
both large and small bowel, no clear transition.
AXR Rigler’s sign
gas on both sides of the bowel wall.
Hounsfield Scale HU is for
greyscale of the pixel in a CT
CT ideal for
monitoring and staging, intracranial pathology, trauma, pre-operative assessment of complex masses, acute abdomen and following abdominal surgery.
MRI enable us to see the distribution of what in the body
fat, tissue and water through the body
the most common weight of MRI image is
T1 weight (anatomy) or T2 (disease)
MRI is ideal for
soft tissues, MSK, intracranial, neck
contraindications for MRI
pacemakers, metallic foreign bodies, shrapnel, surgical clips etc
cardiac CT routine in
suspected dissections, ruptured aneurysms and thrombosis
1st line imaging choice for abnormal LFT’s, jaundice, hepatomegaly, renal dysfunction, abdominal masses
US.
ideal imaging for liver, biliary system, pancreas, and pancreatic duct
MRI.
1st line imaging choice for renal colic
CT
ureterograms useful for
ureteric anatomy, transitional cell carcinoma
CT in acute stroke is often used to exclude
haemorrhage
medical emergencies for imaging
cauda equina syndrome thoracic aortic dissection/ leaking aortic AKI acute Pulmonary oedema Acute abdomen with signs of peritonism traumatic midline cervical tenderness acute focal neurology.
emergencies that shouldn’t be delayed with imaging
testicular torsion
tension pneumothorax
intrabdominal haemorrhage or viscous rupture
sodium reference level
135-145mmol/L
potassium reference level
3.5-5.3 mmol/L
glucose reference level
3.5-5.5mmmol/L
ABG PH
7.35-7.45
ABG PAO2
> 10.6kPa
ABG PACO2
4.7-6.0kPa
male haemoglobin
130-180g/L
female haemoglobin
115-160g/L
Mean cell volume
76-96fL
