Revision Table for Part II exam

Text Genevieve Carbonatto

The following is a summary of what you need to know before sitting the fellowship exam about ultrasound. I have put it in a table form so that it is easier to read. It is not exhaustive but will enable you to answer almost any question

 

Image optimisation Machine

Choose correct probe

  • High frequency – more superficial, linear probe
  • Lower frequency – depth curvilinear probe. Sector probe

Machine adjustment  (Don’t Forget The Giant Family Dog)

  • Depth
  • Frequency
  • TGC
  • Gain
  • Focus
  • Dynamic range

Patient

  • Position (left lateral/sitting/standing, supine)
  • Breathing manoeuvres
  • Operator
  •  Firm pressure with probe to improve contact
  • Adequate gel to improve contact of probe with skin
  • If gas present in abdominal exam – graded pressure or “bouncing” of probe to displace gas
Image artifacts
  1. Acoustic enhancement
  2. Acoustic shadowing
  3. Reverberation artifacts (due to gas or air or between probe and underlying tissue,)
  4. Mirror image (reflection of soundwaves)
  5. Edge artifacts (refraction of sound waves)
  6. Beam width (side lobe artifacts)
  7. Artifacts due to different propagation speeds
  8. Twinkle artifact (renal stones) – cause unknown

 

FAST

Fluid in abdomen

RUQ

  • Fluid in morrison’s pouch – need to fan through
  • Fluid at tip of liver
  • Fluid between diaphragm and liver
  • Fluid at inferior pole of kidney
  • Fluid in costophrenic angle
  • Fluid in right paracolic gutter

LUQ

  • Fluid between spleen and diaphragm
  • Fluid between kidney and spleen
  • Fluid in left paracolic gutter

Pelvis

  • Fluid in retrovesicular space
  • Fluid in pouch of Douglas
  • Fluid between loops of bowel
DVT
  • Lack of compressibility of vein
  • Absence of colour flow
  • Pulse Doppler – lack of augmentation if complete occlusion by thrombus
  • Lack of respiratory phasicity on colour flow suggests proximal thrombus (eg as in May Thurner Syndrome)
AAA
  • Aneurysmal if > 3cm
  • Scan in long and in transverse axis

Features suggestive of rupture (rarely seen)

  • Periaortic haematoma
  • Retroperitoneal haematoma
  • Intraperitoneal fluid or haematoma
  • Colour Doppler flow showing flow of blood out of aorta
  • Tear in aortic wall

 

Dissection Type A
  • Enlarged aortic root in PLAX > 4cm
  • Aortic regurgitation using colour Doppler
  • Aortic flap
  • Pericardial effusion – may be echoic because it is blood
  • Dissection flap in abdominal aorta if dissection extending to abdominal aorta
Dissection Type B
  • Aorta usually not aneurysmal < 3cm
  • Aortic flap visible
  • Colour Doppler differentiates false from true lumen
Pericardial effusion Description

  • Circumferential vs loculated
  • Anechoic vs echoic vs fibrin strands

Size

  • Size inner wall to inner wall of pericardium in end diastole .
  • Physiologic if only seen in systole, small if <1cm, moderate if between 1 and 2 cm, severe if > 2 cm

Haemodynamic effects

  • RA collapse – late diastole, early systole
  • RV collapse – early diastole
  • LA and LV collapse – rarely
  • Above not present if high baseline RV pressures
  • IVC fixed and dilated

 

PE- if large

 

  • Large RV
  • On PLAX view RV bigger than aorta or LA
  • In 4 chamber view RV > 2/3 of LV
  • Small LV
  • D shaped LV
  • +ve MConnel’s sign in 4 chamber view (not a sensitive sign but in conjunction with the 60/60 sign it has a higher sensitivity)
  • Reduced TAPSE < 1.2 cm
  • Fixed and dilated IVC
  • 60/60 sign – (have a look at the post on massive PE on website to understand this “Saddle Embolus”)
  • May see thrombus in pulmonary trunk
  • May see thrombus in IVC
  • DVT on ultrasound
Assessment of RV function RV Size

  • Compare with LV – should be 2/3 of LV (normal) – 4 chamber view
  • Compare with sizes of aorta and LA in PLAX (All 3 should be roughly the same size)
  • Compare with LV in PSAX

RV function

  • Look at longitudinal contraction in PLAX and 4 chamber view
  • Measure TAPSE – should be >1.2 cm

RV walls

  • Look for thickness of RV walls indicating chronic pulmonary hypertension

RA size

Haemodynamic assessment

D shaped LV

  • IVS moves towards LV in Diastole in Volume overload
  • IVS moves towards LV in Systole in Pressure overload
Sepsis IVC < 1 cm collapsibility >50% (collapsibility index)

  • Hyperdynamic heart
  • “kissing ventricles” – almost complete obliteration of LV in systole
Why do US in sepsis ?
  • First line differential diagnosis of shock
  • Early recognition of sepsis related myocardial dysfunction (poor LV contraction)
  • Detection of pre-existing cardiac pathology
  • Haemodynamic monitoring – LVOT VTI to assess fluid responsiveness
  • Screening for cardiac sources of sepsis (endocarditis)
  • Lung ultrasound to look for fluid overload (iatrogenic or 2 to sepsis related myocardial dysfunction)
  • Lung ultrasound to look for consolidation or effusion as cause of sepsis
  • Abdominal ultrasound to look for cause of sepsis  – cholecystitis/ bowel obstruction/perforation
Shock  Objectives “Extended Rush protocol  “ sequence not important

  • To detect cause of shock
  • For Haemodynamic monitoring
Shock Heart

  • LV function and size (cardiomyopathy, infarction, LVOT obstruction)
  • RV function and size (PE, R ventricular infarct)
  • Pericardial effusion (tamponade)
  • Valves (acute MV prolapse, endocarditis)
  • Ascending aorta  – look for dissection and size > 4cm

Heart : Haemodynamic monitoring

Assessment of fluid responsiveness by looking at LVOT VTI

  • Increase of > 15% of VTI after fluid bolus or straight leg raising suggests fluid responsiveness.

IVC size and collapsibility

  • Small < 1 cm and  collapsing > 50 % – fluid depleted
  • Large > 2cm and collapsing < 50% – associated with other causes (PE/cardiomyopathy/tension pneumothorax/pericardial tamponade/underlying pulmonary hypertension )

Lung

  • Pneumothorax
  • Consolidation
  • Pleural effusion
  • Pulmonary oedema

Abdomen

  • Intraabdominal fluid (FAST)

AAA – aneurysm  > 3cm

GB – cholecystitis

Bowel obstruction

DVT

US in shock can be used sequentially

  • Ongoing assessment of fluid responsiveness (LVOT VTI)
  • Ongoing assessment of lung to look for development of pulmonary oedema
Assessment of LV

 

LV size

  • Measure in PLAX at end of diastole. If more than 5.5 cm then enlarged but dependent on body size
  • LV wall thickness
  • Normal wall thickness 1.1cm – measure at end of diastole
  • Thick walls (HOCM, chronic hypertension)
  • Thin walls (ischemia)

LV contraction

  • walls should come together more than 50% in systole
  • Look at radial contraction and longitudinal contraction
  • Walls should contract symmetrically
  • Can measure Ejection Fraction in PLAX or PSAX using

EF = LVEDV – LVESV X 100       LVEDV: left ventricular end diastolic volume

LVEDV                          LVESV: left ventricular end systolic volume

Does not work if there is any regional wall abnormality

  • Can eyeball LV function (poor contraction < 30 %, poor 30 -50%, normal >50%)

Valves

  • MV prolapse
  • Vegetations
  • Stenosis

LA

  • Size

Haemodyamic assessment

  • LVOT VTI – surrogate for Stroke volume
  • SV = VTI X Area of LVOT. Normally VTI should be between 18 and 22 cm
  • Requires a good PW alignment through the LVOT with the sample volume just proximal to Aortic valve
Cholecystitis
  • Wall thickness > 3 mm  in fasted patient
  • Presence of gallstone in neck of GB
  • Presence of sludge
  • Presence of gallstone in cystic duct
  • Hyperaemia of walls using colour Doppler
  • Pericholecystic fluid
  • Sonographic Murphys sign
Causes of GB wall thickening other than cholecystitis
  1. Physiological (postprandial)

2. Non inflammatory

  • Adenomyomatosis
  • carcinoma of the GB
  • leukaemia, multiple myeloma
  • oedema of the GB wall (ascites, hypoalbuminaemia, heart failure, portal hypertension)

3. Adjacent inflammatory disease

  • viral hepatitis
  • alcoholic hepatitis
  • acute pancreatitis
Ruptured Ectopic pregnancy
  • Empty uterus- absent intrauterine gestational sac
  • +/- pseudosac – small collection of blood in the uterus
  • +/-Complex adnexal mass
  • +/- Bagel sign ectopic gestational sac may be visible outside uterus in tube
  • +/- Corpus Luteal cyst
  • Fluid in pouch of Douglas – may be anechoic (non coagulated blood )or hyperechoic (coagulated blood)
  • Fluid in Morison’s pouch
  • Fluid between loops of bowel in pelvis
Pneumonia
  • Subpleural consolidations
  • B lines
  • Lack of lung sliding
  • Shred sign
  • Hepatisation of lung
  • Peripneumonic effusion
  • Consolidation shows flow with colour Doppler
Pulmonary oedema B lines bilaterally and anteriorly : diagnosis possible  only in the absence of interstitial lung disease

B lines

  • artifacts which originate from the pleural line
  • move with lung sliding
  • need to see 3 or more between 2 rib spaces to be pathological
  • artifact goes to the end of the screen

 

Renal colic
  • Hydronephrosis
  • Renal stone with acoustic shadowing –  they do not always produce acoustic shadowing
  • Twinkling artifact
  • Asymmetric ureteric jets

Leave a Reply

Your email address will not be published. Required fields are marked *

Protected with IP Blacklist CloudIP Blacklist Cloud