DOI: 10.1148/rg.254045032
RadioGraphics 2005;25:1017-1030
© RSNA, 2005
Multidetector CT in the Evaluation of Potential Living Donors for Liver Transplantation1
Ana Alonso-Torres, MD,
Jaime Fernández-Cuadrado, MD,
Inmaculada Pinilla, MD,
Manuel Parrón, MD,
Emilio de Vicente, MD and
Manuel López-Santamaría, MD
1 From the Departments of Radiology (A.A.T., J.F.C., I.P., M.P.) and Pediatric Surgery (M.L.S.), Hospital Universitario La Paz, Paseo de la Castellana 261, Madrid 28046, Spain; and the Department of General Surgery, Hopital Ramón y Cajal, Madrid, Spain (E.d.V.). Presented as an education exhibit at the 2003 RSNA Annual Meeting. Received March 11, 2004; revision requested June 30; final revision received October 27; accepted October 28. All authors have no financial relationships to disclose.
Address correspondence to A.A.T. (e-mail: ana.at{at}terra.es).
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Abstract
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Living donor liver transplantation is increasingly being used to help compensate for the increasing shortage of cadaveric liver grafts. However, the extreme variability of the hepatic vascular systems can impede this surgical procedure. Evaluation of potential living donors was conducted in which a two-detector-row computed tomographic (CT) scanner was used to obtain arterial phase and portal dominant phase images following the intravenous injection of contrast material, after which three-dimensional maximum-intensity-projection and volume-rendered images were created. The vascular anatomy was evaluated, with special attention given to the origin and course of the artery to segment IV and the presence of variants, especially those considered relative or absolute contraindications for donation, those requiring reconstruction, or those potentially altering the surgical approach. In addition, graft and remnant liver volumes were determined and the liver parenchyma evaluated. Multidetector CT is proving to be valuable in the evaluation of potential living liver donors, contributing to donor safety and providing comprehensive information about the hepatic vascular anatomy, the liver parenchyma, and graft and remnant liver volume. This information is critical in choosing the most suitable potential donor, in surgical planning, and in obtaining an optimal graft that maintains the balance between blood supply and venous drainage.
© RSNA, 2005
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LEARNING OBJECTIVES FOR TEST 5
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After reading this article and taking the test, the reader will be able to:
- Describe the imaging protocol and postprocessing techniques for dual phase multidetector CT of potential living liver donors.
- Discuss a systematic approach for image interpretation based on surgical considerations.
- Identify important arterial, portal, and hepatic venous variants and discuss their importance for donor selection and surgical planning.
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Introduction
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Improved results of cadaveric liver transplantation have resulted in a dramatic shortage of donor liver grafts, even in countries such as Spain, where the donation rate is relatively high (33.7 per 1 million persons in 2002) (1). To meet the needs of an increasing number of potential liver transplant recipients, alternative approaches have been developed, namely, reduced-size transplantation, split transplantation, and living donor liver transplantation (LDLT). However, LDLT may cause morbidity in an otherwise healthy donor who generously takes such an important risk for a loved one. Therefore, donor safety is a primary concern, and selection protocols are of paramount importance to preserve donor health by excluding unsuitable candidates for either medical or anatomic reasons (2). With the development of the new multidetector computed tomographic (CT) techniques, the radiologist plays a relevant role, providing, with a minimally invasive procedure, valuable information that will be useful in choosing the most suitable candidate and in identifying anatomic variants that may alter the surgical approach.
In this article, we review the hepatic segmental anatomy as well as the normal anatomy and anatomic variants of the hepatic vasculature. We also discuss surgical considerations in left lateral segment (LLS) versus right lobe donation and describe an imaging protocol for multidetector CT evaluation of potential living liver donors. In addition, we discuss and illustrate the multidetector CT features and surgical implications of important vascular variants and volumetric measurements.
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Hepatic Segmental Anatomy
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The liver has three major vascular systems upon which hepatic segmental anatomy nomenclature is based: two hepatopetal systems (arterial and portal venous systems) and the hepatic venous system for drainage. The segmental division of the liver, first described by the French surgeon Couinaud, has functional implications because each segment has its own vascular supply and may be resected without affecting the rest of the liver parenchyma. This nomenclature should be helpful in establishing clear communication with the transplantation surgeon (Fig 1) (3).
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Figure 1. Drawing illustrates the segmental anatomy of the liver, along with the pattern of hepatic venous drainage, the ramifications of the portal venous system, and the planes of liver transection (dotted line indicates plane of transection in LLS donation, solid line indicates plane of transection in right lobe donation). IVC = inferior vena cava, LHV = left hepatic vein, MHV = middle hepatic vein, MP = main portal vein, R = round ligament, RHV = right hepatic vein.
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Normal Anatomy of the Hepatic Vasculature
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In normal arterial anatomy, the common hepatic artery arises from the celiac trunk, from which the left gastric, gastroduodenal, and proper hepatic arteries arise, the latter dividing distally at the hilus into right and left branches (Figs 2, 3) (4). The artery to segment IV is usually considered a small branch from the LHA.
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Figure 2. Three-dimensional volume-rendered (VR) image shows the normal hepatic arterial anatomy. CHA = common hepatic artery, GDA = gastroduodenal artery, LGA = left gastric artery, LHA = left hepatic artery, PHA = proper hepatic artery and its bifurcation (arrow), RHA = right hepatic artery, SA = splenic artery, SMA = superior mesenteric artery.
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Figure 3. Anterior VR image shows the normal arterial anatomy with a prominent corkscrew-like gastroduodenal artery (GD) and a filiform distal right hepatic artery (RHA) and left hepatic artery (LHA) (arrows). Because third-order vessels were not visible, the arterial study was considered inadequate, and conventional angiography was performed.
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In normal venous anatomy, the portal vein bifurcates at the hilus into right and left pedicles. The right pedicle in turn bifurcates into anterior and posterior branches, both of which further bifurcate into ascending and descending branches. Each of these four branches supplies a segment of the right lobe. The left pedicle divides into three branches, one for each segment of the left lobe.
The hepatic venous anatomy is extremely variable, the most common pattern consisting of three main hepatic veins. The right hepatic vein (RHV) is often the largest of the three and drains the greatest part of the right lobe (5). The middle hepatic vein (MHV) drains the central sector of the liver (segments IV, V, and VIII), and its branching and confluence pattern is quite variable (6). The MHV usually joins the left hepatic vein (LHV), which drains the LLS (segments II and III), to form a common trunk that empties into the inferior vena cava (IVC).
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Anatomic Variants
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Vascular variations affecting arterial, portal venous, and hepatic venous supply are quite common. Arterial variants are present in approximately 42% of cases (4). In his classic report, Michels (7) first described a basic classification system for common and rare hepatic arterial variants, the most common of which were a replaced or accessory RHA arising from the superior mesenteric artery (SMA) (Fig 4) and a replaced or accessory LHA arising from the left gastric artery (Fig 5) (4,7,8). Variants of the artery to segment IV are seen in nearly 47% of cases, a fact that may have relevant implications (9) in that segment IV may be supplied by one or more branches arising from the LHA, the RHA, or both (10).
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Figure 4. Thick-slab coronal oblique maximum-intensity-projection (MIP) image from CT data shows a replaced RHA (open arrow) arising from the SMA (arrowhead). Note the artery to segment IV (solid arrow) arising from the LHA. This situation is suitable for right lobe donation.
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Figure 5. Coronal oblique VR image shows a replaced LHA (arrow) arising from the left gastric artery (arrowhead), a situation that is suitable for LLS donation. GD = gastroduodenal artery, RH = right hepatic artery.
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Portal venous variants appear in approximately 10% of cases. These variants mainly affect the right portal vein (RPV) and may be classified into five types of branching as defined by the origin of the branch of the anterior segments (Fig 6) (11,12).
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Figure 6. Drawings illustrate the types of RPV branching (11): type A, normal anatomy (92.5% of cases); type B, early bifurcation or trifurcation (2.5%); type C, extraparenchymal branching of the anterior branch from the LPV (2.5%); type D, intraparenchymal branching of the anterior branch from the LPV (1.7%); and type E, an undivided main portal trunk (0.8%). Types B and C result in two venous openings that should be surgically reconstructed in cases of right lobe donation. The chosen technique for reconstruction depends on the distance between the right anterior and posterior branches. Types D and E represent absolute contraindications for right lobe donation. Moreover, the shortness of the transverse portion of the LPV complicates LLS donation.
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Relevant variants of the inconstant hepatic venous system are short accessory (dorsal) RHVs that drain the posterior segments (segments VI and VII) independently into the IVC at a variable distance from the RHV. These accessory RHVs are larger and more common in cases of a non-dominant RHV. Left lobe variants that may alter the surgical approach are an LHV or segment III vein draining independently into the IVC, or the latter vessel draining into the MHV.
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Surgical Considerations: LLS versus Right Lobe Donation
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LDLT first became an important treatment choice in children with end-stage liver diseases, and mainly LLS grafts were used. As experience accumulated in these cases, the practice was extended to right lobe grafts. There are many other types of grafts (monosegmental, left lobar with or without the MHV, left lobar with the MHV plus the caudate lobe, right lateral sector, dual, whole liver); nevertheless, right lobe and LLS grafts represent the two ends of a wide spectrum, with quite different technical considerations (Table) (16).
During harvest of the LLS, parenchymal transection is performed along the falciform ligament, whereas during harvest of the right lobe it is performed approximately 1 cm to the right of the MHV and parallel to the Cantlie line, which runs from the gallbladder fossa to the IVC, following the MHV (13,17).
Total liver volume has been reported to have a relatively constant relation to body weight; however, lobar volumes are quite variable (18). The ratio between graft weight and recipient body weight or between graft volume and the estimated standard liver volume of the recipient has been used to determine the ideal liver volume for recipients. It is considered acceptable when these parameters are at least 0.8% and 40%, respectively, provided that the liver parenchyma is normal, with no fatty infiltration (2). When the graft volume is insufficient, mainly in right lobe donation, there is a risk of "small-for-size" syndrome: Grafts are prone to dysfunction, not only because of insufficient liver volume, but also because the graft may sustain injury related to excessive portal perfusion (19). In LLS transplantation, grafts tend to be large for size, which may cause vascular compression and difficulty in abdominal closure.
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Imaging Protocol
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The objectives of multidetector CT in the evaluation of potential donors are (a) to depict the arterial, portal venous, and hepatic venous anatomy, (b) to help identify important vascular variants, (c) to help identify the origin and course of the dominant arteries to segment IV, (d) to allow volumetric measurements of the graft, whole liver, and remnant liver, and (e) to help detect unexpected focal or diffuse liver lesions.
Our imaging protocol, performed with a two-detector-row CT scanner (Asteion; Toshiba, Tokyo, Japan), consisted of obtaining two image sets after intravenous injection of 135–150 mL of a nonionic contrast agent (iohexol, 300 mg of iodine per milliliter) at a rate of 3 mL/sec, with the following parameters: 120 kV, 210 mAs, and a rotation time of 0.75 seconds. To ensure accuracy, the timing of the arterial phase (collimation, 2 mm; pitch, 3; reconstruction interval, 1 mm) was determined with a real-time bolus tracking system (Sure Start, Toshiba). The bolus was injected into the abdominal aorta at the level of the origin of the celiac axis, with a detection threshold of 100 HU. Portal dominant phase imaging was started 60 seconds after contrast material injection (collimation, 3 mm; pitch, 3.5; reconstruction interval, 1.5 mm).
Total liver and graft volumes were measured with a paintbrush method after hand tracing of axial liver margins, the frequency of selection depending on changes in liver contour. Particular care was taken to exclude the IVC, extrahepatic portal vein, and major fissures (20). The virtual hepatectomy plane was chosen as follows: for right lobe harvest, a relatively avascular plane to the right of the MHV; for LLS harvest, a plane along the falciform ligament.
Analysis of the image data was based on source images as well as two-dimensional multiplanar reformatted images and three-dimensional (3D) MIP and VR postprocessed images created on a commercially available workstation (Vitrea 2; Vital Images, Minneapolis, Minn).
Overlapping thin-slab axial MIP images were used to depict the arteries to segment IV, whereas thin- and thick-slab axial and coronal MIP images were used to depict the hepatic venous anatomy. This technique offers excellent contrast between the liver parenchyma and the enhanced vessels, which is useful for evaluating hepatic veins and arteries supplying segment IV. On the other hand, the origin or course of contrast material–enhanced arteries reconstructed with VR techniques and overlapping the hepatic parenchyma may be misinterpreted (14).
Several authors have described their imaging protocols with different multidetector CT systems (9,15,21,22).
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Multidetector CT Findings and Surgical Implications
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Vascular Anatomy and Variants
It should be emphasized that the evaluation of the donor must be individualized and should never be performed apart from evaluation of the recipient; it is the combination of characteristics of both the donor and the recipient that helps determine whether the two are suitable for consideration for LDLT. Hence, close cooperation between radiologists and surgeons is mandatory to achieve optimal results (23).
Multidetector CT is an excellent tool for mapping out the hepatic vascular anatomy; it is essential that the radiologist be familiar with the normal liver anatomy and be able to recognize the presence of variants, especially those considered relative or absolute contraindications for donation, those requiring reconstruction or multiple anastomoses, and those that may alter the surgical approach (24,25).
Arterial Anatomy
Although virtually none of the known arterial variants is considered a contraindication for surgery, the hepatic artery is subject to many anatomic variations that may alter the surgical approach (19,26).
When normal arterial anatomy is found, a hepatic artery with sufficient length for reconstruction is difficult to obtain because only a part of the liver is harvested (27). Thus, it is important to recognize the proper hepatic artery bifurcation and to measure the length of the RHA (in cases of right lobe donation) or LHA (in cases of LLS donation) before the next bifurcation (Fig 2) (20). Even so, findings such as filiform or redundant arteries may impede arterial reconstruction (Fig 3).
Some variants are suitable for the transplantation surgeon, whereas others are not. A replaced RHA or LHA enables the surgeon to perform safer anastomoses because these arteries are usually longer (Figs 4, 5) (11). In contrast, the presence of an accessory RHA or LHA (Fig 7) would theoretically lead to the creation of a dual anastomosis because hepatic arteries are, as a rule, considered end arteries (12). However, there are sometimes intrahepatic anastomoses, which allow the ligature of the smaller artery.
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Figure 7. Thick-slab coronal oblique MIP image shows an accessory LHA (arrow) arising from the left gastric artery. L = left hepatic artery, R = right hepatic artery. This situation would lead to the creation of a dual anastomosis, unless intrahepatic anastomoses, which allow the ligature of the smaller branch, are demonstrated.
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Arterial variants may consist of the substitution of a single branch, such as the RHA or LHA, for two or more branches. Such a variant is more common and usually more complex in the LHA than in the RHA (Figs 8, 9). The radiologist should measure the distance between these two (or more) branches; if they are close together, a single anastomosis can be performed; otherwise, multiple arterial reconstruction may be necessary (2).
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Figure 8. Thick-slab axial MIP image shows a complex arterial branching pattern. The CHA trifurcates (solid arrow) into the gastroduodenal artery and two RHAs, from one of which arises the LHA (open arrow) and the artery to segment IV (arrowhead). This situation makes right lobe retrieval extremely difficult.
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Figure 9. Thick-slab coronal oblique MIP image shows two LHAs. The proximal artery (arrow) arises at the proper hepatic artery bifurcation, whereas the distal artery (arrowhead) arises from the RHA and has a smaller caliber. The distal LHA should be preserved in cases of right lobe donation to ensure an adequate postsurgical liver volume.
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After right lobe resection, the remnant liver volume approaches the critical limit; thus, undisturbed inflow to segment IV, which accounts for up to 40% of postsurgical liver volume, is crucial to prevent liver failure (13,17). However, as mentioned earlier, the arterial supply to segment IV may be quite variable (Figs 10–13). To preserve the branches to segment IV, the radiologist should carefully identify their precise origin as well as the distance to the bifurcation of the proper hepatic artery. Because the branches will traverse the transection plane, one should be especially aware of when they arise from the RHA in cases of right lobe donation.
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Figure 10. Thin-slab axial MIP image shows the artery to segment IV (arrow) arising from the LHA (arrowhead). This situation is suitable for right lobe donation. Such an artery to segment IV should be transected in LLS donation; however, the consequences are not as relevant as in right lobe donation as long as the remnant liver volume is not significantly compromised.
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Figure 11. Coronal VR image shows the artery to segment IV (arrow) arising from the right hepatic artery (R) very close to the proper hepatic artery bifurcation, from which point the left hepatic artery (L) arises.
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Figure 12. Thin-slab axial MIP image shows a dual supply to segment IV (arrows) arising from the right (R) and left (L) hepatic arteries. In such cases, if right lobe donation is being considered, it is important to evaluate the dominance of one branch over the other to decide the sacrifice of the smaller one. Graft and remnant liver volumes should also be taken into account.
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Figure 13. Thin-slab axial MIP image shows a triple supply to segment IV (arrows). Two vessels arise from the right hepatic artery (R), and a third vessel arises from the left hepatic artery (L).
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Portal Venous Anatomy
When normal portal venous anatomy is found (Fig 14), in cases of right lobe donation, the length of the RPV from the main trunk bifurcation to the next bifurcation should be measured. Because of the common size mismatch between the hepatic vessels in the adult liver and those in the pediatric recipient, in cases of LLS donation, the transverse diameter of the left portal vein (LPV) should also be reported (28).
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Figure 14. Anterior VR image shows the normal portal venous anatomy. The left (L), main (M), and right (R) portal veins are well visualized. SMV = superior mesenteric vein, SV = splenic vein.
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Portal venous variants mostly affect right lobe donation. Particular attention should be paid to variants resulting in two venous openings, namely, trifurcation (Fig 15) or extraparenchymal branching of the anterior branch from the LPV (Figs 16, 17). If the branches are close together, they can be joined together to make a single orifice (venoplasty). If they are not, they can be anastomosed separately—one to the RPV and one to the LPV in the recipient—or connected to a Y-shaped vascular graft for a single anastomosis (Fig 18). Therefore, the distance between the two branches must be carefully measured (29). Moreover, the shortness of the transverse portion of the LPV in these cases may pose difficulties during retrieval and implantation of the LLS graft.
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Figure 15. Thick-slab coronal MIP image shows a trifurcation of the main portal vein (M) into the anterior right (A), posterior right (P), and left (L) portal veins. In cases of right lobe donation, this variant would lead to the creation of two venous openings that should be reconstructed.
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Figure 16. Coronal VR image shows extraparenchymal branching of the anterior branch (A) from the left portal vein (L) close to the bifurcation of the main portal vein (M). In cases of right lobe donation, this situation allows the reconstruction of the two venous openings into a single orifice. Dotted line indicates the transection plane for LLS retrieval, leaving a short portal vein for reconstruction. R = right portal vein.
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Figure 17. Coronal VR image shows extraparenchymal branching of the anterior branch (A) from the left portal vein (L) far (18 mm) from the bifurcation of the main portal vein (M). Nevertheless, the right lobe was harvested and the portal vein was reconstructed with a Y-shaped graft. R = right portal vein.
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Figure 18. Drawings illustrate anatomic variants that result in two venous openings being either joined together to make a single orifice (venoplasty) (A), anastomosed separately to the LPV and RPV of the recipient (B), or connected to a Y-shaped vascular graft for a single anastomosis (C). D = donor, G = graft, R = recipient.
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Although variants affecting the LPV are not common, they should also be looked for (Fig 19).
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Figure 19. Coronal VR image shows a vein (arrow) arising from the main portal vein (MPV) and supplying the LLS. Note the extraparenchymal branching of the right anterior branch (A) from the left portal vein (L). R = right portal vein. In this case, the coincidence of two distinct portal variants led to the selection of a more suitable candidate.
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Intraparenchymal branching of the anterior branch from the LPV and an undivided MPV are considered absolute contraindications for right lobe donation (2).
Hepatic Venous Anatomy
Images of the portal venous anatomy, even when this anatomy is considered normal, should be used to guide the surgeon during the retrieval procedure (Figs 20, 21). Large venous branches that cross the transection planes may cause unexpected bleeding during retrieval and should be preserved when they are of significant size (ie, 5 mm in diameter). If these significant branches are transected, the drained sectors may also develop congestion and late ischemia, compromising the functional volume of the graft.
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Figure 20. Thick-slab axial MIP image shows the normal hepatic venous anatomy. The left hepatic vein (L) forms a common trunk with the middle hepatic vein (M), whereas a large right hepatic vein (R) drains independently. There are no other small branches that drain independently into the IVC.
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Figure 21. Thick-slab coronal oblique MIP image shows the normal hepatic venous anatomy of the middle (M) and left (L) hepatic veins, which join to form a common trunk. Note the early confluence of two branches (arrows) to form the main middle hepatic vein, a "safe" anatomy for right lobe donation.
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During harvesting of the right lobe, significant accessory RHVs that drain a wide area of the posterior sector should be preserved and implanted separately on the recipient IVC. When such veins are identified, their distance to the RHV should be measured in the coronal plane. If this distance exceeds 4 cm, it may be difficult to surgically implant both veins with a single partially occluding clamp (Fig 22) (19).
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Figure 22. Coronal VR image shows a large accessory inferior RHV (arrow) draining into the IVC. The distance to the RHV (arrowhead) must be carefully measured in cases of right lobe donation.
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MHV anatomy is actually the key to right lobe donation, and variations in the confluence pattern of the MHV may be of paramount importance. Usually, during right-sided hepatectomy, one or more significant branches of the MHV will need to be transected (Fig 23) (30). This situation is more common in cases of either (a) late confluence of branches forming the MHV (Fig 24) or (b) dominance of the MHV over the RHV, in which case the MHV can provide drainage for a large portion of the right lobe (Fig 25 ). However, reconstruction of the MHV is necessary if the resection plane contains significant segment V or VIII veins (13). Some authors believe that including the MHV in the graft (extended right lobe donation), which is a more compromising procedure for the donor, is a simpler and more straightforward approach, provided the liver remnant is adequate (5). In all such cases, 3D models are helpful for depicting the precise relationship between hepatic veins.
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Figure 23. Thick-slab axial MIP image shows a branching pattern of the middle hepatic vein (M) consisting of an early confluence of two branches (arrows) to form the main venous trunk (arrowhead). In cases of right lobe donation, this situation allows safe transection to the right of the MHV.
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Figure 24. Thick-slab axial MIP image shows the late confluence of two branches (straight solid arrows) to form the middle hepatic vein (M) very close to the IVC (open arrow). Note the two branches to segment IV (curved arrows) draining into the left hepatic vein (L). These two branches would be transected in cases of LLS retrieval.
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Figure 25a. Dominance of the MHV over the RHV. (a) Thick-slab axial MIP image shows a large middle hepatic vein (M) that drains the anterior segments and segment VII (straight arrows). Several RHVs (arrowheads) drain the posterior segments. Note the large vein that drains segment IV independently into the IVC (curved arrow). (b) Thick-slab coronal MIP image shows the RHV (open arrow) draining segment VI into the IVC (arrowhead) 33 mm below the MHV (solid arrow).
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Figure 25b. Dominance of the MHV over the RHV. (a) Thick-slab axial MIP image shows a large middle hepatic vein (M) that drains the anterior segments and segment VII (straight arrows). Several RHVs (arrowheads) drain the posterior segments. Note the large vein that drains segment IV independently into the IVC (curved arrow). (b) Thick-slab coronal MIP image shows the RHV (open arrow) draining segment VI into the IVC (arrowhead) 33 mm below the MHV (solid arrow).
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During harvesting of the LLS, unexpected bleeding may occur when a large tributary to the LHV, draining part of segment IV, traverses the falciform ligament (Fig 24) (12). An LHV draining independently into the IVC is a suitable variation; on the contrary, variations resulting in two venous openings, namely, veins of segments II and III draining independently (Fig 26), should be reconstructed (31).
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Figure 26. Thick-slab coronal MIP image shows the branch of segment III (arrowhead) draining into the middle hepatic vein (M). The branch of segment II drains independently into the IVC.
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Volumetric Measurements
Different studies have reported excellent agreement between real graft volumes and measured CT volumes (17,32). Obtaining accurate estimates of the graft and whole liver volumes is critical to ensure that the graft and remnant liver contain sufficient volume to (a) guarantee liver regeneration and (b) sustain function in the immediate postoperative period (Fig 27). Therefore, the virtual hepatectomy plane should be carefully evaluated, especially in right lobe donors with no clear anatomic landmarks to indicate the limits between the right and left lobes (14).
It has been reported that liver regeneration terminates after the liver has achieved 75%–95% of its original size, approximately 6–8 weeks after harvest. The regeneration ratio is proportional to the amount of resection, being significantly higher after right lobe donation than after LLS donation, since the remnant liver has to regenerate more liver volume to meet functional demands (Fig 28) (33,34).
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Figure 28a. Liver regeneration after right lobe donation. (a) Axial CT scan obtained before donation shows the LPV (arrow) dividing the left lateral segment (LLS) from segment IV, when calculated total liver volume was 1,768 cm3 and graft volume was 1,082 cm3. (b) Axial CT scan obtained 14 months after donation shows hypertrophy of the remnant liver (estimated volume, 1,505 cm3). This volume represented 85% of the previous total liver volume and 139% of the graft volume. LLS = left lateral segment, arrow indicates the LPV.
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Figure 28b. Liver regeneration after right lobe donation. (a) Axial CT scan obtained before donation shows the LPV (arrow) dividing the left lateral segment (LLS) from segment IV, when calculated total liver volume was 1,768 cm3 and graft volume was 1,082 cm3. (b) Axial CT scan obtained 14 months after donation shows hypertrophy of the remnant liver (estimated volume, 1,505 cm3). This volume represented 85% of the previous total liver volume and 139% of the graft volume. LLS = left lateral segment, arrow indicates the LPV.
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Conclusions
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Multidetector CT is a valuable tool in the evaluation of potential living liver donors that provides complete and comprehensive information on the hepatic vascular anatomy, the liver parenchyma, and volumetric measurements. It contributes to donor safety—the highest priority during the selection process and surgical planning—and allows an optimal graft to be obtained that maintains the balance between blood supply and venous drainage.
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Footnotes
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Abbreviations: IVC = inferior vena cava, LDLT = living donor liver transplantation, LHA = left hepatic artery, LHV = left hepatic vein, LLS = left lateral segment, LPV = left portal vein, MHV = middle hepatic vein, MIP = maximum-intensity-projection, MPV = main portal vein, RHA = right hepatic artery, RHV = right hepatic vein, RPV = right portal vein, SMA = superior mesenteric artery, VR = volume-rendered, 3D = three-dimensional
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References
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Abstract
LEARNING OBJECTIVES FOR TEST...
