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Caudate–right lobe ratio

Caudate-right lobe ratio (C/RL) is used in the assessment of livers, usually in the setting of cirrhosis, in which there is atrophy of the right lobe with hypertrophy of the caudate lobe

  • image: axial slice immediately below the bifurcation of the main portal vein
  • line 1: a parasagittal line drawn through the right lateral border of the portal vein
  • line 2: a parasagittal line drawn through the left lateral border of the caudate lobe
  • line 3: line orthogonal to lines 1 and 2 midway between the portal vein and the IVC extended to the right liver edge
  • RL measurement: along line 3, from right liver edge to line 1
  • C measurement: along line 3, between line 1 and line 2
  • caudate-right lobe ratio: C/RL
  • C/RL <0.6 = normal (does not exclude cirrhosis) 
  • C/RL 0.6-0.65 = borderline
  • C/RL >0.65 = 96% likely to be cirrhotic
  • C/RL >0.73 = 99% likely to be cirrhotic

An alternative placement of line 1 has been proposed by Awaya et al. as being more sensitive and specific 2. Rather than line 1 intersecting the right lateral border of the main portal vein, they describe drawing line 1 through the right lateral aspect of the right portal vein bifurcation.

Article information

rID: 8071
Section: Approach
Synonyms or Alternate Spellings:
  • Caudate-right lobe ratio (C/RL)

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Cases and figures

  • Figure 1: caudate-right lobe ratio
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  • Cirrhosis and ascites
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