COMPUTED TOMOGRAPHY EVALUATION - PowerPoint Presentation

Slide1

COMPUTED TOMOGRAPHY EVALUATION OF HEPATIC PERFUSION DISORDERS

I MARZOUK MOUSSA, F KSONTINI, L BEN FARHAT, A MANAMANI, N DALI, L HENDAOUIMEDICAL IMAGING AND INTERVENTIONNAL DEPARTEMENT, MONGI SLIM HOSPITAL, LA MARSA TUNISIA

GI12Slide2

Introduction

The liver has a dual blood supply , which comes from the hepatic artery ( 25% of vascularization) and the portal vein ( 75% of vascularization).There are several communications between both systems including hepatic sinusoids and peribiliary

plexus . when vascular compromise of hepatic blood supply or venous drainage occurs ,control systems intervene inducing in imaging abnormalities of parenchymal

enhancement time varying.Slide3

These hepatic perfusion disorders

(HPD) can be detected with multiphases computed tomography imaging

through the study of the parenchymal

enhacement kinetic.HPD are

commonly

associated

with

changes in

arterial

, portal or

venous

flow and

sometimes

have mixed

origin

.Slide4

Material and Methods

A retrospective study including seven patients with

hepatic perfusion disorders :

hepatic abscess Rendu-Osler disease

Pancreatic head cancer with an hepatic

hilar

lymph node compressing the hepatic artery

Budd Chiari syndrome

Superior vena cava thrombosis

Hepatic cirrhosis

Thrombosis of the left portal branch.Slide5

Results

Arterial origin Arterial occlusion :

It rarely induces hepatic

perfusion disorders in imaging except in case of:

*

Thrombosis

of

hepatic

artery

in transplantation

*An

associeted

venous

occlusion (figure 3 ) .Slide6

CT findings :

a triangular segmentary or lobar hypodensity persisting in different phases of Iodin contrast

injection with hilar somet and

peripheral base . Intrahepatic bile

ducts

are sensitive to

arterial

ischemia

and

may

necrose giving biliar false cyst.

Arterial origin Slide7

Figure 3 :Lymphadenopathy

of hepatic hilum () secondary to cancer of pancreas own

tail ()

, compressing the hepatic artery

and the portal

vein

causing

HPD of the

left

liver

()

Arterial origin Slide8

Arterial flow increase

:Hypervascular tumor .Intense inflammatory reaction ( figure 1) .Hereditary

Hemorrhagic Telangiectasia (HHT) called Disease

of Rendu_Osler (figure 2) .

Arterial originSlide9

Figure 1

:Hepatic abcess of segment II and III ( ) ,

surrounded by an abnormal enhacement of the

hepatic parenchyma (



)

Arterial originSlide10

HHT is a vascular disease with autosomal

dominant transmission characterized by multiple telangiectases.It affects mucocutaneous tissue most frequently, but any part of the body can be affected including the liver traduced by numerous arteriovenous shunts between hepatic artery branches and branches of the hepatic or portal veins.

Arterial

originSlide11

Figure 2

: Disease of Rendu _Osler : significant increase

of the caliber of the hepatic

artery (

)

and

its

branches

with

many

arteriovenous fistulas and abnormal

parenchymal

enhacement of

left liver ()

.

Arterial originSlide12

Portal origin

HPD are often caused by venous inflow obstruction due to portal vein thrombosis , tumor invasion ,compression or surgical ligation .The causes of portal vein thrombosis include neoplasm that invades or compresses the portal system , infection process , embolisation , hypercoagulative states and myeloproliferative disorders.Slide13

CT findings : intense enhacement of the hypoperfused parenchyma in hepati arterial phase images ( explicated

by arterial flow increase ) that returns

to normal in portal phase .

Figure 4:

Abnormal

contrast

inhacement

of the

left

liver

caused

by thrombosis of the ipsilateral

portal branch.

Potal originSlide14

Venous

origin Cardiac liver .Budd Chiari syndrome ( figure 5).

CT findings :

hypoperfusion of peripheral parenchyma

contrasting

with

a normal perfusion of the central

parenchyma

.Slide15

Budd-Chiari syndrome is defined as lobar or segmental hepatic venous outflow obstruction at the level of the hepatic veins or inferior vena cava (IVC) and may be primary or secondary .

This Hepatic venous outflow obstruction leads to elevation of sinusoidal pressure and diminished portal venous flow, which culminates in centrilobular congestion followed by necrosis and atrophy.

Venous originSlide16

Figure

5 Budd Chiari syndrome : significant hapertrophy of segment I (←

) that normally

inhace contrasting with the

peripheral

parenchyme

which

remains

hypodense

(

).

Venous originSlide17

Mixed origin

Arterio portal fistula

(APF) :An APF is

an organic or a functionnal communication between an arterial

hepatic

branch

and the portal

venous

system ,

resulting

in redistribution of arterial flow into a focal region of portal venous flow .

The causes of APF

include

:

liver cirrhosis (figure 6) , hepato cellular carcinoma , iatrogenic

fistulae after liver biopsy ,

traumatic or spontaneous fistulae .Slide18

Figure

6 :

Hepatic cirrhosis :

Early enhacement of segment III (

)

that

is

irregularly

shaped , non systematized , with opacification of the

left

portal

branch in

arterial phases through an arterio portal fistula

.Mixed

originSlide19

Superior

vena cava obstruction : A reflux through arterio portal collateral inheritance rarely

used ( figure 7) .

Figure 7:

Intense opacification of segment III (



)

on portal phase

through

arterio

portal

collateral

inheritances

secondary to

superior vena cava thrombosis.

Mixed originSlide20

Discussion

Hepatic diffuse diseases ,benign conditions and malignant tumors

are commonly associeted with changes in

arterial , portal or hepatic venous flow, detected

in

imaging

by

abnormal

parenchymal

enhacement

after iodin contrast injection ; which

can

be

inerpreted as false positives and negatives in tumor detect and

staging.Slide21

The mechanism can

be obstruction , fistulae or compression .Such images are very common : thrombosis of the portal branch induces an early

parenchymal enhancement disappearing in portal phase. Arterial obstruction induces segmentary or lobar hypodensity persisting in different phases of

iodin contrast injection . Slide22

Arterio_portal fistulae can be mistaken with hypervascular tumors or intense inflammatory reaction.

Cardiac liver and Budd Chiari syndrome induces a normal enhancement of the central parenchyma contrasting with a low enhancement in the peripheral tissue.Slide23

Conclusion

The study of different aspects of hepatic perfusion disorders which are sometimes misleading allows to not confuse them with organic hepatic lesion.