European Journal of Radiology 53 (2005) 425–432

MDCT imaging of post interventional liver: a pictorial essay

Stefania Romanoa, ∗, Giovanni Tortoraa, Mariano Scaglionea, Francesco Lassandroa,Guido Guidia, Roberto Grassib, Luigia Romanoa

a Department of Diagnostic Imaging, Section of General and Emergency Radiology, A.Cardarelli Hospital, Viale Cardarelli, 9, 80131 Naples, Italyb Institute of Radiology, Department “Magrassi-Lanzara”, Second University of Naples, Naples 80138, Italy

Received 15 December 2004; received in revised form 16 December 2004; accepted 17 December 2004

Abstract

In this pictorial essay, we consider the post operative MDCT findings after liver resection, transplantation, surgical managed major traumaand radiofrequency ablation of focal lesions.

Common complications such as fluid collections, hemorrhage, biloma, vascular disease, hematoma, abscesses will be also considered.© 2005 Elsevier Ireland Ltd. All rights reserved.

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eywords:Liver, MDCT; Liver transplantation, complications, MDCT; Hepatic trauma, surgery, MDCT; Liver, surgery, hepatic artery, hepatic vein,DCT

. Introduction

CT acquired a pivotal role in the imaging of liver; theelative recently introduced Multi Detector row equipmentsay enhance the study of pattern of surgical or interventional

aused hepatic changes. Post operative findings may alter theormal appearance of the parenchyma and correlated vas-ulature; moreover, development of complications, that mayiffer in type and importance and are related to the opera-

ive manoeuvre performed (resection for neoplasm or majorrauma, liver transplantation, surgical or radiological guidedrainage, thermoablation of focal lesion etc) are essential pa-ameter to consider in the diagnostic imaging evaluation.

In this pictorial essay, after a brief description of currentrinciples for liver resection, therapeutic intervention as wells liver transplantation, we report some common and unusualost interventional MDCT findings and complications.

.1. Liver resection—preliminary notes

Hepatic surgery is based on the segmental structure of the

the anatomic criteria are strictly followed, and “atypicawhen minor resections are requested[1]. Liver parenchymmay be divided in multiple segment or sectors, and somesifications are known[2,3]. The surgical segmental anatodescribed by Couinaud in 1957 and commonly used in Euis essentially based on the distribution of the portal branand the three hepatic veins[4]; the middle hepatic vein dividethe liver parenchyma in two main lobes, right and left, eof these may be divided by the relative hepatic veins intodial and lateral segments, to form four main sectors[4]. Eachsector may be divided into anterior and posterior segmconsidering a transverse plane through the right and left pbranches[4], to obtain a total of eight segments. The vaslature follows the lobar and segmental division of the lparenchyma; the basic unit is done by a portal and heartery branch and a segmental biliary duct for each hemiThe common hepatic artery usually originates from the ctrunk (Fig. 1a) and after bifurcation at the liver hilum it dvides into right and left hepatic artery, from one of eacmiddle hepatic artery to supply liver segment IV generoriginates[5]. Vascular variants (Fig. 1b), as the evidence

iver parenchyma and may be considered as “typical”, when

∗ Corresponding author.E-mail address:stefromano@libero.it (S. Romano).

aberrant left hepatic artery or anomalies in origin and courseof the right hepatic artery are known. The confluence of thesuperior mesenteric vein and the splenic vein give rise to themain portal vein that runs posteriorly in the hepato-duodenal

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720-048X/$ – see front matter © 2005 Elsevier Ireland Ltd. All rightsoi:10.1016/j.ejrad.2004.12.019

ed.

426 S. Romano et al. / European Journal of Radiology 53 (2005) 425–432

Fig. 1. MDCT 3D reconstructions. Hepatic artery originating from the celiac trunk with aneurysmatic dilatation of the splenic artery (a) and from theabdominalaorta (b).

ligament[5]. The main portal vein originates the right and theleft portal branches at the porta hepatis[5]; following divi-sions are anterior and posterior branches for the right hepaticvein and superior and inferior branches for the left hepaticvein; there are three hepatic vein to drain the liver segments:right, middle and left veins[5]; in venous vascularizationvariants of the main portal vein and the segmental branchesare common[5].

Liver surgery may pay attention to the resection planesin order to provide an optimal vascular supply and biliarydrainage for the remaining parenchyma[1]. Atypical resec-tions are limited to the excision of the affected hepatic areawith an adjacent tissue, facing the edge of the sections[1].Typical resections are left or right hepatectomy; the firstone comprises liver parenchyma supplied by the left hepaticartery and portal vein branches, whereas the latter is limitedto the right hepatic lobes[1]. Liver parenchyma offer regen-erating process for an anatomical and functional substitutionof resected segments; after left lobectomy, right hepatic lobebecome hypertrophic extending below the costal skeleton,whereas after right lobectomy, the left hepatic lobe extends inepigastrium, with dislocation of the stomach (left) and trans-verse colon (low)[1]. Surgery for major hepatic trauma withhepato-capsular fractures is performed to excise the laceredparenchyma suturing the involved damaged vessels to avoidn rgerf ge.

1dal-

i icale , end-s neo-

plasms, metabolic diseases), that offers a 5-year survival rateof 50–70% approximately[6]. An accurate evaluation of thetransplant candidate has to be performed in order to minimizecomplications as well as to exclude factors that may affectthis operative procedure[7]. After searching for pulmonary,cardiac and renal changes, infective diseases, exclusion ofextrahepatic malignancy as well as an accurate staging ofhepatic neoplastic existing lesions is imperative[7]. Vascu-lar anatomy has to be studied[7]; the ideal arterial supplysuppose the existence of a normal celiac trifurcation and bi-furcation of the common hepatic artery, in order to allow anarterial anastomosis at the bifurcation of the common hep-atic artery or at bifurcation into the right and left hepaticarteries[7]. Evaluation of the celiac axis and the of the por-tal vein perviety as well as of splenic artery aneurysms are

F ws as

ecrosis; hepatic lobectomy is performed in case of laractures with impossibility to stop hemorrhage or bilorrha

.1.1. Liver transplantationLiver transplantation is an effective therapeutic mo

ty for several irreversible acute and chronic pathologntities (end-stage chronic parenchymal liver diseasestage chronic cholestatic liver disease, acute liver failure,

ig. 2. MDCT multiplanar reconstruction post liver transplantation shotenosis of the hepatic artery.

S. Romano et al. / European Journal of Radiology 53 (2005) 425–432 427

Fig. 3. MDCT axial scans of transplanted liver. Note the periportal hypodensity and the perviety of the hepatic artery (a–c).

Fig. 4. MDCT axial scans. Hepatic abscesses in transplanted liver. Note fluid hypodense collections in which a drainage tube is placed (a); some littlebilomasare also noted in the liver parenchyma (b).

428 S. Romano et al. / European Journal of Radiology 53 (2005) 425–432

Fig. 5. MDCT inhomogeneous density area from post transplantationhematoma of the right lobe.

required in order to exclude any potential controindicationto transplantation or development of vascular complicationsof the transplanted liver[7]. Orthotopic transplantation, full-size or split liver (in this case, two separate parts of the donorliver, suitable for two different recipient, are created) graft,starts with vascular anastomoses, venous (from the supra-hepatic vena cava to the portal vein) and arterial, followedby the biliary anastomoses[8]. Living donor transplanta-tion technique is similar to a right hepatectomy; however,in this case the vascular and biliary branches of the right hep-atic lobe are short as the major branches have to be used asdonor vascular access of the remaining hepatic left segments[8], so that vascular reconstruction of the hepatic artery andportal vein positioning a graft is requested in many cases[8].

1.1.2. Liver tumor ablation—interventional procedure1.1.2.1. Thermal ablation.Patients affected by liver neo-plastic lesions (no more than 5, not larger than 5 cm) who arenot eligible for liver resection, may undergo other therapeu-

Faloc

ig. 6. MDCT axial scans. Liver transplantation in 25-year-old girl (a). Six mnd c); note the endoluminal defect of opacification at level of suprahepatic

atero-lateral caval reconstruction (d). Note also a dilatation of the intrahepaperative evidence of bilomas (one of them presenting air bubbles from drainollections and their increased dimensions (g).

onths after, evidence of hematic peritoneal and retroperitoneal collections (bbranching in the inferior vena cava probably localized in the cul-de-sacof the

tic biliary ducts (d). The patient was submitted to a second transplantation; postage) (e and f); a following control one week later shows the persistence ofbiliary

S. Romano et al. / European Journal of Radiology 53 (2005) 425–432 429

Fig. 6. (Continued).

tic interventions, such as the thermal ablation, using electriccurrents in the RF range to induce necrosis of the focal le-sions and of perilesional rim of hepatic parenchyma[9]. Thistreatment may be performed during surgery or by CT-USpercutaneously guided interventions.

1.1.2.2. Other procedures.Interstitial laser photocoagula-tion, cryosurgery, percutaneous ethanol injection as well astranscatheter arterial chemoembolizations of the focal liver

lesions may also be performed as treatment of neoplastic nod-ules.

2. MDCT imaging in post operative liver

In a post operative evaluation, a biphasic study in suspi-cion of active bleeding, often integrated by unenhanced ba-sic study may be preferred to a standardized protocol based

Fig. 7. MDCT axial scans of transplanted liver. Large subphrenic and perihepatic fluid collections, showing disomogeneous density for evidence of blood clotsa

nd serum fluid (a and b).

430 S. Romano et al. / European Journal of Radiology 53 (2005) 425–432

Fig. 8. MDCT coronal and sagittal (a and b) reconstructions in hepatic major trauma; note the pseudoanurysmatic dilatation of the arterial intrahepatic branches.

on contrast enhanced scanning in portal phase. Intravenouscontrast medium (120–150 ml of iodinated non ionic contrastmedium) may be administered with a scan delay of 20′′, 60′′ or70′′ depending on the selected protocol; enhancement by bo-lus triggering may be used when vascular study is requested.Thin collimations of 4 mm× 2.5 mm or 4 mm× 1.25 mm (4-slice scanner) or 16 mm× 1 mm (16-slice scanner), a pitchequal to 1.3–1.5, to obtain thin slice width (2–4 mm) andoptimal multiplanar reconstructions[10], are important pa-rameters to allow a correct imaging evaluation of the liverparenchyma.

Post operative features may include normal findings aswell as various complications. Evidence of fluid collec-tions in the resection bed and hypertrophy of the remain-ing parenchyma after hemiepatectomy[5] may be a commonfinding in the early post operative period, as well as the ev-idence of inhomogeneous low density areas long term per-sisting in case of segmental resection. In the study performedto evaluate the liver after transplant, it is essential to provide

a correct visualization of the parenchyma perfusion[11] aswell as of vascular perviety or disease (stenosis, thrombosis,aneurysms) (Figs. 2 and 3) [12–16]. Normal findings in trans-planted liver are the high density areas due to the suture linesat level of the superior and inferior caval anastomosis[5];evidence of periportal hypodensity (Fig. 2) in the early postoperative period may not be considered as pathological as itspersistence after some months is[5]. Complications such asbile leaks with biloma formation, biliary anastomotic stric-ture, hematoma and abscesses may be observed in post oper-ative liver (Figs. 4–7), from transplant or resection[5,17]; it isuseful to evaluate the vascular pattern in post trauma (Fig. 8).Hematomas may have the appearance of hypodensity areasclose to the resection margins, whereas bilomas may occurat this level or in the porta hepatis, however, their densityvalue cannot allow a differentiation from other entities suchas old hematoma, seroma, infected fluid collections[5,18].Fluid collections may be also represents abscesses, with ev-idence of a peripheral hyperdensity rim. It is important to

homog f resecti

Fig. 9. MDCT axial scans of transplanted liver (a and b). Note the in eneous solid tissue due to a large recurrent lesions near the margin oon.

S. Romano et al. / European Journal of Radiology 53 (2005) 425–432 431

Fig. 10. MDCT axial scans. Post thermoablation of focal liver lesions. Note the hyperdensity rim of the treated hypodense nodules (a and b) and the peritonealfluid. Evidence of blushes of enhancement from active lesions are also noted in arterial phase (c and d).

evaluate post interventional liver with a multiphasic study insuspicion of neoplastic recurrence (Fig. 9). Necrosis from ra-diofrequency ablation[5,19] appears as hypodense areas onpre-contrast CT images (Fig. 10), however, it is necessary toexclude any recurrency in the post operative follow-up, witha multiphasic study to detect any hypervascularization areasfrom persistence of disease; however, a subtle enhancing rimperipherally to the treated lesions may be evident for sev-eral month after thermoablation as post interventional find-ing, such as some other associated evidences (perihepatic orpleural effusion, biliary duct ectasia, portal vein thrombosis,areas of hepatic infarction)[5,9].

3. Conclusions

MDCT may provide an optimal imaging method in evalu-ation of different normal findings and complications of postoperative liver, especially in dynamic evaluation of vascularperviety and parenchymal perfusion.

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