liver anatomy: focused on segment anatomy on...

Liver Anatomy: Focused on Segment Anatomy on Imaging

Dong Ho Lee, M.D.

Department of Radiology

Seoul National University Hospital

대한간암학회 2018 Feb-9

Contents

• Liver Anatomy: General Aspect

• Liver Anatomy: US

• Liver Anatomy: CT

F/60, 7 year after DDLT

Liver Anatomy: General

• Liver – Norma liver: 1.44 – 1.66 kg

• Heaviest internal organ

• Largest gland

– Located in RLQ

– Accessory digestive system • Produce bilirubin

• Fat and glucose metabolism


• Glisson’s capsule

• Peritonealized except for…

– GB fossa

– Around IVC

– Bare area:

• liver-diaphragm-lung


Ligament

• Coronary

• Triangular Right, Left

• Falciform

• Round (lig. teres)


Bare area • Triangular ligament

– Right –Left

• Coronary ligament

• IVC sulcus

• Falciform ligament

• Fissure for lig. venosum


Fissure • Gallbladder

• Ligamentum teres

• Ligamentum venosum

• Transverse fissure

• Main (Inter) lobar fissure (Cantlie line)

• Inferior accessory fissure


Lesser omentum • Hepatogastric lig

• Hepatoduodenal lig

– Portal triad

• Omental (epiploic)

foramen (of Winslow)


• Hepatic Vessels – Dual supply

• hepatic artery 20-25%, portal vein 75-80%

– Hepatic artery

• Celiac axis Common hepatic artery Proper hepatic artery Right & Left hepatic artery: classic type, 55%

– Anatomical variation

• Replaced RHA from SMA: portocaval space • Replaced LHA from LGA: fissure for ligamentum

venosum


• Hepatic Vessels

– Portal vein • SMV + Splenic vein Main portal vein

• Right portal vein Anterior & Posterior

• Left portal vein Transverse portion Umbilical portion (umbilical vein) Medial & Lateral

– Anatomical variation


• Hepatic Vessels

– Hepatic vein

• RHV, MHV+LHV IVC

• Caudate lobe – directly into IVC

• Accessory hepatic vein

• Right inferior hepatic vein

R

M L


• Segmental anatomy: Couinaud (1954)

8 segments based on injection corrosion model with portal vein


• Segmental anatomy

• Right / Left lobe

– Middle hepatic vein

– Cantlie line (GB - IVC)


• Segmental anatomy

• Right lobe • Anterior/Posterior segment

– Right hepatic vein

• Left lobe • Medial/Lateral segment

– Left hepatic vein – Left portal vein – Falciform ligament


• Superior / Inferior segment

– Right portal vein

– Left portal vein

Bismuth-Couinand nomenclature

• Caudate lobe


• Segmental anatomy: Couinaud (1954)

Subsegment Couinaud Bismuth

Caudate lobe I

Left lateral superior subsegment II

Left lateral inferior subsegment III

Left medial segment IV

Left medial superior subsegment IVa

Left medial inferior subsegment IVb

Right anteroinferior subsegment V

Right posteroinferior subsegment VI

Right posterosuperior subsegment VII

Right anterosuperior subsegment VIII


• Liver anatomy for diagnosis – Systematic dx based on vasculature, reduces the

chance of overlooking pathologic lesions

– If multiple lesions found by several different

imaging modalities are compared for the exact location and number, the dx would become more definitive

– In the follow-up study, if the lesions are

numbered, they would be more accurately evaluated


• Liver anatomy for surgery

– Liver segment understanding of spatial relation of a lesion to the vascular system enables the surgeon to decide on the most appropriate operation method

– Recognition of the lesion and its relation to the vascular system by intraoperative US improves the results of resection

Contents





US Anatomy of the liver

• Lobar and Segmental Anatomy

Couinaud C. Etude do Ia veine porte intra-hepatique. Presse Med 1953;61:1434-1438.

• 3 longitudinal boundaries

– Right lobe - Left Lobe

• IVC, fissure for GB (Cantlie line), MHV

– RL anterior segment – RL posterior segment

• RHV

– LL medial segment - LL lateral segment

• LHV, U. portion of LPV, fissure for ligament teres

• 1 transverse boundary

– Right & left main portal pedicle

US anatomy


• Cantlie line


• MHV

Right lobe

Left lobe

Middle hepatic vein


• Fissure For GB – shallow fissure

Right lobe

Left lobe Fissure for GB

US Anatomy





• RHV






• RHV

Right posterior segment

Right anterior segment

Right lobe

Right hepatic vein





• RHV


• LHV, U. portion of LPV, fissure for ligamentum teres



US Anatomy


• LHV Left lobe

Left medial segment

Left lateral segment

Left HV


• Umbilical Portion of LPV

Left lobe

Left medial segment

Left lateral segment LPV


• Fissure for Ligamentum Teres

Left lobe

Fissure for ligamentum teres

Left medial segment

Left lateral segment





• RHV





US Anatomy


• Transverse Boundary


• Fissures and Ligament

– 3 Vertical fissures

• Fissure for GB

• Fissure for ligamentum venosum

• Fissure for ligamentum teres/ Falciform ligament

– 1 Transverse fissure


• Fissure for Ligament Venosum

– Obliterated ductus venosus

– LPV-LHV

– Caudate lobe/left lobe

CL

LL

CL

LL


• Fissure for ligamentum teres

– Obliterated umbilical vein

– Left medial segment/lateral segment


• Transverse Fissure

– Barely visible

– Invagination of hepatic

pedicle into liver

– PV, HA, bile duct, Glisson’s

capsule

– Echogenic


• Vascular Anatomy

– Portal vein

– Hepatic artery

– Hepatic vein

– Bile duct

PV BD

HA

Portal triad


• Portal vein

• Anechoic tubular structure

– With a strong echoic wall

• Branching from porta hepatis

• Penetrates the central portion of segment

• Continuous flow toward the liver

RPV

Ant.

Post.

LPV

Horizontal

4

2

3 Umbilical

RPV


• Hepatic artery

– Pulsatile flow

– Systolic peak

– Hepatopetal direction


• Hepatic Vein – Anechoic tubular structure /w an imperceptible wall

– The anatomic boundaries of each segment

– Drain to IVC, Pulsatile flow

– Influenced by cardiac cycle, respiration


• Accessory or Inferior RHV

– 6%~10% of population

– Drains from S6

– Hepatic surgery (TPL)

– Budd-Chiari syndrome

• Intra-hepatic collateral


• Size – Measured longitudinally at the midclavicular line

– >15cm: Hepatomegaly

– Indirect criteria

• Extension lower to right kidney

• Blunted inferior margin of right liver

• Extension to LUQ

normal


• Echo Texture – Homogeneous

– Fine echoes

– Sl. hyper- or iso- echoic than kidney

– Hypoechoic than spleen

LK

Spleen

Liver

Contents





CT Anatomy of the liver

• CT protocol

Pre-contrast AP

PVP DP or EP


• CT protocol

– Pre-contrast

• Stone disease evaluation

• Object enhancement 여부의 파악

• Hemorrhagic lesion detection

• Liver parenchymal attenuation의 evaluation

• Calcification, surgical material의 파악

• Lipiodol laden lesion evaluation


• CT protocol

– Arterial phase

• Early arterial phase – Also called aortic phase

– Artery anatomy evaluation에 최적화되어 있는 phase

– Solid organ: enhancement가 minimal

• Late arterial phase – Also called pancreatic phase

» Pancreas parenchymal enhancement가 maximum

– Liver hypervascular lesion evaluation

» HCC, hypervacular metastasis


• CT protocol

Early arterial phase


• CT protocol

EAP

LAP PVP


• CT protocol

– Portal venous phase

• Liver parenchymal enhancement 가 maximum – Liver: portal venous flow 75%, hepatic arterial flow

25%

• Good liver to lesion contrast

• Liver anatomy의 평가에 가장 적절

• Focal liver lesion detection 의 reference phase


• CT protocol

– Delayed phase (Equilibrium phase)

• HCC characterization 을 위한 phase

Radiology 2005; 234: 460-467


• CT protocol – Portal venous phase

• Good liver to lesion contrast: reference • Delineation of liver anatomy

– Late arterial phase • Pancreatic lesion evaluation • Hypervascular liver lesion (HCC): reference

– Pre-contrast scan

• Stone disease, hemorrhagic lesion evaluation • Liver parenchymal attenuation • True enhancement 여부의 파악

– Delayed phase

• HCC evaluation


• Arterial MIP: HA variation


• Portal MIP: PV variation

Summary

• Liver anatomy

– 8 segments

• Imaging study

– Anatomic landmark: separate each segment

– Fissure and vascular anatomy

Acknowledgements

• Byung Ihn Choi

• Se Hyung Kim

• Hyun Kyung Yang

liver anatomy: focused on segment anatomy on...

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