Background: The liver has a region called the hepatic hilum (HH) where structures enter and exit: anteriorly, the left and right hepatic ducts; posteriorly, the portal vein; and between these, the left and right hepatic arteries. The objective of this review is to know how variants in structures of the hepatic hilum are associated with clinical alterations of the liver. Methods: The databases Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS were researched until January 2024. The methodological quality was evaluated with an assurance tool for anatomical studies (AQUA). The pooled prevalence was estimated using a random effects model. Results: A total of six studies met the selection criteria established in this study for meta-analysis. The prevalence of hepatic hilus variants was 9% (CI = 5% to 13%), and the heterogeneity was 83%. The other studies were analyzed descriptively and with their respective clinical considerations in the presence of the variant, such as the high incidence of the Michels type III variant; among the portal vein variants, the type III variant of the Cheng classification stands out and in biliary anatomy, and the IIIa variant stands out according to the Choi classification. Conclusions: This review allowed us to know in detail the anatomical variants of HH; the structure with which the greatest care should be taken is the hepatic artery because of the probability of metastatic processes due to increased blood distribution in the hepatic lobules. Finally, we believe that new anatomical and clinical studies are needed to improve our knowledge of the relationship between HH variants and liver alterations or surgeries.

To qualitatively and quantitatively compare gadobutrol with gadopentetate dimeglumine (Gd-DTPA) in abdominal contrast-enhanced magnetic resonance angiography (CE-MRA) and contrast-enhanced magnetic resonance imaging (CE-MRI) during one-stop imaging.

This prospective, blinded, multicentre, intra-individual comparison study was approved by the institutional review board. All patients underwent gadobutrol- and Gd-DTPA-enhanced MRA and MRI. Qualitative analysis for vessels was performed using a three-point scale while quantity analysis was performed by signal-to-noise ratio (SNR). Visceral organs enhancements were also analysed. A Wilcoxon matched-pair signed-rank test was used to evaluate the quality and quantity results.

One hundred and twelve patients were enrolled. Quality analyses results for large vessels and small vessels of gadobutrol and Gd-DTPA were 18.38±1.51 and 6.76±1.58 and 17.87±1.84 and 6.09±1.55, respectively. Wilcoxon signed-rank tests revealed gadobutrol was significantly superior to Gd-DTPA (p=0.036) for small vessels. For large vessel quantity analysis, gadobutrol demonstrated significantly higher signal-to-noise ratios (SNR; p=0.041) than Gd-DTPA, with mean values of 948.156±349.731 and 838.925±248.197. There was no statistically significant in enhancement of liver, spleen, and renal tissue during gadobutrol- and Gd-DTPA-enhanced imaging (p>0.05). One patient reported an adverse event. Dizziness and vomiting occurred after injection of Gd-DTPA.

The present study demonstrates gadobutrol-enhanced MRA was superior to that of Gd-DTPA without statistical significance in visceral organ enhancement. It indicates gadobutrol may be more suitable for abdominal one-stop imaging for CE-MRA and CE-MRI by improving depiction of vessels in MRA images.

To retrospectively evaluate gadoxetic acid-enhanced magnetic resonance angiography (MRA) using controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) technique for mapping hepatic vascular anatomy in potential living liver donors, with CT angiography (CTA) as reference standard.

82 potential living liver donors who underwent MRA and CTA were enrolled in this HIPAA-compliant IRB-approved study. MRA and CTA images were evaluated by two reviewers in consensus with respect to (1) image quality scores for depiction of the hepatic vessels and (2) accuracy of MRA for determining the hepatic vascular variants with CTA as reference standard. The image quality scores were compared using Fisher's exact test between MRA and CTA.

The accuracy for determining the hepatic arterial, portal, and hepatic venous variants and segment IV arterial origin was 73, 90, 79, and 55%, respectively, compared to CTA. However, subjective image quality for depiction of hepatic arteries in MRA was significantly lower than CTA (p < 0.001). The portal and hepatic venous image quality was almost equal in both modalities (p = 0.059) except left hepatic vein being depicted better on CT images (p = 0.023).

Gadoxetic acid-enhanced MRA using CAIPIRINHA technique is feasible for mapping hepatic vasculature in potential living liver donors, with moderate accuracy for arterial variants and good to excellent results for hepatic and portal vein variants, compared with CTA. However, the specific delineation of segment IV arterial origin was possible in just over half of the liver donors with MRA.

To compare MRI using gadobenate dimeglumine (Gd-BOPTA) vs. gadoxetic acid disodium (Gd-EOB-DTPA) for the assessment of biliary anatomy of potential liver donors.

76 potential liver donors (39 M/37 F, mean 38 years) who underwent 1.5T MRI using Gd-BOPTA (n = 37) or Gd-EOB-DTPA (n = 39) were retrospectively evaluated. T2 cholangiogram (T2 MRC) and delayed hepatobiliary phase (HBP) T1 cholangiogram (T1 MRC) (performed during HBP 20 min after injection of Gd-EOB-DTPA and 1-2 h after Gd-BOPTA injection) were obtained in addition to MR angiogram/venogram. Two independent observers evaluated image quality (IQ) and conspicuity scores (CS) of the biliary system. Biliary anatomy was assessed in 3 reading sessions (T2 MRC, T1 MRC, and combined T2/T1 MRC). Reference standard consisted of consensus reading of two separate observers of all image sets, clinical/surgical information and intraoperative cholangiogram when available. Datasets were compared using the Mann-Whitney U test or Chi-squared test.

There was no difference in IQ for T1 MRC using either contrast agent or T2 MRC vs. T1 MRC for both observers (all p values >0.07). There was superior CS for T2 MRC vs. Gd-BOPTA T1 MRC for both observers and T2 MRC vs. Gd-EOB for one observer (p < 0.001). No difference was found for biliary variant detection for T1 MRC (with either contrast agent) vs. T2 MRC. Combined T2/T1 MRC demonstrated improved sensitivity for biliary variant detection using Gd-BOPTA for both observers (p < 0.004) and Gd-EOB-DTPA for one observer (p < 0.001).

Equivalent image quality was found for T1 MRC obtained with Gd-BOPTA or Gd-EOB-DTPA and T2 MRC. T1 MRC is equivalent to T2 MRC for detection of variant biliary anatomy, and the combination of sequences may have added value.

To explore the efficiency, cost, and time for examination of one-stop-shop gadoxetic acid disodium (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) in preoperative evaluation for parent donors by comparing with multidetector computer tomography combined with conventional MR cholangiopancreatography (MDCT-MRCP).

Forty parent donors were evaluated with MDCT-MRCP, and the other 40 sex-, age-, and weight-matched donors with Gd-EOB-DTPA-enhanced MRI. Anatomical variations and graft volume determined by pre- and intra-operative findings, costs and time for imaging were recorded. Image quality was ranked on a 4-point scale and compared between both groups.

Gd-EOB-DTPA-enhanced MRI provided better image quality than MDCT-MRCP for the depiction of portal veins and bile ducts by both reviewers (p < 0.05), hepatic veins by one reviewer (p < 0.05), rather hepatic arteries by both reviewers (p < 0.01). Sixty-nine living donors proceeded to liver donation with all anatomical findings accurately confirmed by intra-operative findings. The "in-room" time of Gd-EOB-DTPA-enhanced MRI was 12 min longer than MDCT-MRCP. Gd-EOB-DTPA-enhanced MRI was cheaper than MDCT-MRCP (US$519.72 vs. US$631.85).

One-stop-shop Gd-EOB-DTPA-enhanced MRI has similar diagnostic accuracy as MDCT-MRCP and can provide additional benefit in terms of costs and convenience in preoperative evaluation for parent donors.

The objective of this study was to determine the diagnostic accuracy of contrast-enhanced magnetic resonance angiography (MRA) when used in the preoperative evaluation of hepatic vascular anatomy in living liver donors.

A computer-assisted literature searching of EMBASE, PubMed (MEDLINE), and the Cochrane library databases was conducted to identify potentially relevant articles which primarily examined the utility of contrast-enhanced MRA in the preoperative evaluation of hepatic vascular anatomy in living liver donors. We used the Q statistic of chi-squared value test and inconsistency index (I-squared, I(2)) to estimate the heterogeneity of the data extracted from all selected studies. Meta-Disc software (version 1.4) (ftp://ftp.hrc.es/pub/programas/metadisc/Metadisc_update.htm) was used to perform our analysis.

Eight studies were included in the present meta-analysis. A total of 289 living liver donor candidates and 198 patients who underwent liver harvesting were included in the present study. The pooled sensitivities of hepatic artery (HA), portal vein (PV), and hepatic vein (HV) in this meta-analysis were 0.84, 0.97, and 0.94, respectively. The pooled specificities of HA, PV, and HV were 1.00, 1.00, and 1.00, respectively. The pooled diagnostic odds ratios of HA, PV, and HV were 127.28, 302.80, and 256.59, respectively. The area under the summary receiver-operating characteristic curves of HA, PV, and HV were 0.9917, 0.9960, and 0.9813, respectively.

The high sensitivity and specificity demonstrated in this meta-analysis suggest that contrast-enhanced MRA was a promising test for the preoperative evaluation of hepatic vascular anatomy in living liver donors.

The objective of this study was to determine whether unenhanced magnetic resonance (MR) angiography using repetitive arterial or vein labeling (RAVEL) is feasible to visualize effectively the intrahepatic portal vein (PV) at 3.0 T.

Forty patients underwent liver MR imaging (MRI) with unenhanced MR portography using RAVEL. Two radiologists performed a consensus review of unenhanced MR portography and portal-phase MRI with regard to anatomic type of PV, vessel conspicuity, and image quality.

For determination of the anatomic type of PV, the 2 techniques were equivalent. There were tendencies toward increased conspicuity for right segmental PV and its branches with unenhanced MR portography and for left PV with conventional MRI, although significant differences were not found between MRIs (P > 0.05). Image quality for unenhanced MR portography was poor in 1, moderate in 8, and good in 31 patients.

Unenhanced MR portography using RAVEL at 3.0 T is feasible and provides effective visualization of intrahepatic PV.

The advent of gadolinium-based "hepatobiliary" contrast agents offers new opportunities for diagnostic magnetic resonance imaging (MRI) and has triggered great interest for innovative imaging approaches to the liver and bile ducts. In this review article we discuss the imaging properties of the two gadolinium-based hepatobiliary contrast agents currently available in the U.S., gadobenate dimeglumine and gadoxetic acid, as well as important pharmacokinetic differences that affect their diagnostic performance. We review potential applications, protocol optimization strategies, as well as diagnostic pitfalls. A variety of illustrative case examples will be used to demonstrate the role of these agents in detection and characterization of liver lesions as well as for imaging the biliary system. Changes in MR protocols geared toward optimizing workflow and imaging quality are also discussed. It is our aim that the information provided in this article will facilitate the optimal utilization of these agents and will stimulate the reader's pursuit of new applications for future benefit.

To compare T2W-MRCP and T1W contrast-enhanced MRC (CE-MRC) using Gd-BOPTA for evaluation of biliary-enteric anastomotic (BEA) stricture.

Twenty-one patients who were suspected to have BEA stricture underwent T2W-MRCP and CE-MRC on a 1.5T scanner. Images were evaluated for evidence of anastomotic stricture. Composite gold standard was used including the findings on percutaneous transhepatic cholangiogram or percutaneous transhepatic biliary dilatation, surgery, alkaline phosphatase level and clinical follow-up.

The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of T2W-MRCP for the diagnosis of anastomotic stricture were 94.4%, 80%, 94.4% and 80% respectively. On CE-MRC, biliary excretion was seen in only 60.87% anastomoses and only these were taken for analysis. The sensitivity, specificity, PPV and NPV of CE-MRC for the diagnosis of anastomotic stricture were 40%, 75%, 80% and 33.3%. The combined evaluation of T2W-MRCP and CE-MRC showed sensitivity, specificity, PPV and NPV of 83.3%, 80%, 93.8% and 57.1%.

At present, T2W-MRCP is still the diagnostic modality of choice in the evaluation of patients with BEA stricture and the usage of Gd-BOPTA enhanced MRC is inappropriate in this setting.

To compare gadoxetic acid disodium (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) with gadobenate dimeglumine (Gd-BOPTA)-enhanced MRI in preoperative living liver donors for the evaluation of vascular and biliary variations.

Sixty-two living liver donors who underwent preoperative MRI were included in this study. Thirty-one patients underwent MRI with Gd-EOB-DTPA enhancement, and the other 31 underwent MRI with Gd-BOPTA enhancement. Two abdominal radiologists retrospectively reviewed dynamic T1-weighted and T1-weighted MR cholangiography images and ranked overall image qualities for the depiction of the hepatic artery, portal vein, hepatic vein, and bile duct on a 5-point scale and determined the presence and types of normal variations in each dynamic phase. Semiquantitative analysis for bile duct visualization was also conducted by calculating bile duct-to-liver contrast ratios.

No statistical differences were found between the two contrast media in terms of hepatic artery or bile duct image quality by the two reviewers, or in terms of portal vein image quality by one reviewer (P > 0.05). Gd-BOPTA provided better image qualities than Gd-EOB-DTPA for the depiction of hepatic veins by both reviewers, and for the depiction of portal veins by one reviewer (P < 0.01). The two contrast media-enhanced images had similar bile duct-to-liver contrast ratios (P > 0.05). Regarding diagnostic accuracies with hepatic vascular/biliary branching types, no significant differences were observed between the two contrast media (P > 0.05).

Gd-EOB-DTPA could be as useful as Gd-BOPTA for the preoperative evaluation of living liver donors, and has the advantage of early hepatobiliary phase image acquisition.

Gadobenate dimeglumine (Gd-BOPTA) is taken up by functioning hepatocellular cells and is partially excreted into the biliary system; therefore, it can be used as a potential intrabiliary contrast agent for magnetic resonance cholangiography applications for various clinical conditions such as obstructive disorders (e.g., choledocholithiasis, hepatolithiasis), inflammatory disorders (e.g., acute cholecystitis, cholangitis), benign biliary disorders, and pre- and postprocedural evaluation of the biliary system. In this pictorial review, we aimed to demonstrate the clinical applications of Gd-BOPTA as an intrabiliary contrast agent for imaging various biliary pathologies.

To investigate the feasibility of the use of gadobenate dimeglumine (also known as Gd-BOPTA) -enhanced T1-weighted MR cholangiography in diagnosis of acute cholecystitis.

This prospectively designed institutional review board-approved HIPAA-compliant study was done between January and November 2007. We included 11 consecutive patients (7 male, mean age 59 years) who presented to the emergency room with acute right upper quadrant pain and with equivocal physical examination and/or ultrasound findings. The control group included 15 patients who underwent liver MRI with Gd-BOPTA. All patients underwent contrast-enhanced (CE) MR cholangiography examinations. CE-MR cholangiography was performed on a 1.5 Tesla magnet using 3D T1-weighted high resolution isotrophic volume examination (THRIVE) obtained at the 90th min after intravenous injection of Gd-BOPTA. Imaging features detected on CE-MR cholangiography were correlated with operative and histopathologic findings.

In the control group, GD-BOPTA was visualized within the gallbladder in all subjects. For the study group, gallstones were present in nine patients (n = 7 both in gallbladder and cystic duct, n = 1 only in gallbladder, n = 1 only in cystic duct) on MRCP. Hydropic gallbladder was detected in seven patients, significant wall thickening in seven patients, and pericholecystic free fluid in 6 patients. On delayed phase CE cholangiography, significant enhancement of gallbladder wall was seen in 10 patients, and contrast agent excretion into gallbladder was absent in all patients. Surgery was performed in 10 patients, and cholecystostomy was done in 1 patient. Surgery and histopathology findings were consistent with cholecystitis in all patients.

In addition to anatomical assessment, Gd-BOPTA-enhanced MR cholangiography can provide functional evaluation similar to HIDA scintigraphy in diagnosing acute cholecystitis in patients with acute right upper quadrant pain and equivocal findings.

To evaluate the performance of magnetic resonance (MR) and multidetector computed tomography (MDCT) in the assessment of living donor's vascular and biliary anatomy, having surgical findings as reference standard.

Thirty-two living liver donors underwent MR cholangiography (1.5-T; standard cholangiography pulse sequences and delayed acquisitions after administration of biliary contrast agent) for biliary anatomy evaluation. MDCT (16-row multidetector scanner, multiphase protocol, 3mm slice thickness) was also performed in all cases for the assessment of vascular anatomy before transplantation. Hepatic veins (<4mm in diameter) were not considered. MR and MDCT images interpretation was performed by two reviewers by consensus, based on source axial images, multiplanar reformats, and three-dimensional (3D) postprocessing images. Surgical intraoperative findings were used as standard of reference.

At surgery, 17 biliary anomalies, 3 portal anomalies, 32 venous and 8 arterial variants were found in the 32 patients. MR correctly identified 15/17 biliary anomalies, with a sensitivity of 88% and a specificity of 93%. MDCT correctly identified 8/8 arterial, 3/3 portal and 29/32 venous variants, with a sensitivity of 100% and 91%, respectively, and a specificity of 100%.

MR and MDCT proved to be efficient in evaluating living liver donor's biliary and vascular anatomy.

DIPS is to create a portosystemic shunt directly between the portal vein and the retrohepatic inferior vena cava (RIVC) without passing through the hepatic vein. It has been recommended that the DIPS could be applied when routine TIPS is unsuccessful or the patient has anatomical variations of the hepatic vein. The aim of this study was to identify the safe area of the RIVC where the DIPS can be safely established.

The lengths of the safe and unsafe areas of the RIVC were measured. The tributaries of the RIVC were examined. The diameter of these tributaries was measured and their incidence and relation to the safe area of the RIVC were observed. The puncture distances of DIPS and TIPS were measured and compared.

The liver together with the RIVC was collected from 31 adult cadavers (age 32-65 years; M/F 25/6). 1. The safe and unsafe areas of the RIVC: the total length of the RIVC was 70.1 +/- 13.0 mm (33.1-92.0 mm), whereas the length of the safe area of the RIVC was 54.3 +/- 12.3 mm (20.2-71.1 mm), which was about over 70% of the total length. The length of the unsafe area at the upper end was 5.9 +/- 1.8 mm (3.0-10.2 mm), and at the lower end was 8.9 +/- 2.9 mm (3.1-20.0 mm). 2. The tributaries of the RIVC: In about 90% of the cadavers (90.3%; 28 out of 31), the LHV and MHV had the common trunk. The other three cadavers (9.7%; 3 out of 31) had independent RHV, MHV and LHV. There were 217 of small hepatic veins draining into the lower segment of the RIVC. Over 70% of the small hepatic veins were smaller than 5 mm in diameter and distributed on the anterior and left wall of the lower RIVC. 3. Puncture distances of the DIPS and TIPS: The distances from the bifurcation of the portal vein to the RIVC, to the right and to middle hepatic veins were 31.2 +/- 7.9 mm (15.0-47.2 mm), 38.6 +/- 8.1 mm (17.2-59.0 mm), and 46.6 +/- 8.2 mm (34.0-68.1 mm), respectively. Thus, the puncture distances via the RIVC, RHV and LHV were significantly different (P < 0.001). The puncture distance of the DIPS was shortest.

Anatomically, DIPS is a feasible interventional procedure to make a intrahepatic shunt between IVC and portal vein directly, and has its anatomical advantages compared to TIPS.

Accurate preoperative assessment of the hepatic vascular and biliary anatomy is essential to ensure safe and successful hepatic surgery. Such surgical procedures range from the more complex, like tumor resection and partial hepatectomy for living donor liver transplantation, to others performed more routinely, like laparoscopic cholecystectomy. Modern noninvasive diagnostic imaging techniques, such as multidetector computed tomography (CT) and magnetic resonance (MR) imaging performed with liver-specific contrast agents with biliary excretion, have replaced conventional angiography and endoscopic cholangiography for evaluation of the hepatic vascular and biliary anatomy. These techniques help determine the best hepatectomy plane and help identify patients in whom additional surgical steps will be required. Preoperative knowledge of hepatic vascular and biliary anatomic variants is mandatory for surgical planning and to help reduce postoperative complications. Multidetector CT and MR imaging, with the added value of image postprocessing, allow accurate identification of areas at risk for venous congestion or devascularization. This information may influence surgical planning with regard to the extent of hepatic resection or the need for vascular reconstruction.

To compare contrast-enhanced magnetic resonance (MR) cholangiography (CE-MRC) performed with gadobenate dimeglumine with T2-weighted MRC (T2-MRC) for visualization of the bile ducts in nondilated biliary systems.

Twenty consecutive patients who underwent MR imaging (MRI) of the liver and pancreas with nondilated intrahepatic ducts were included in this retrospective study. T2-weighted MRC was performed using a multislice, high-resolution fat-suppressed half-Fourier acquisition turbo spin-echo sequence. Contrast-enhanced MR cholangiography was performed using a fat-suppressed 3-dimensional fast low-angle shot sequence acquired 1 to 1.5 hour after intravenous administration of gadobenate dimeglumine. For image interpretation, the biliary system was divided into 8 segments. Two readers graded visualization of each segment on T2-MRC and CE-MRC using a 5-point scale (0, nonvisualization; 4, excellent visualization). Final opinion for each sequence was rendered by consensus. Superiority of visualization was assessed using the McNemar test and comparing adequately (visualization scores 3 and 4) and inadequately (visualization scores 0, 1, and 2) visualized segments of the ducts on both sequences. Interobserver variability was assessed with kappa statistics.

Overall and segment-based evaluation revealed superior visualization of biliary segments with CE-MRC compared with T2-MRC. We also found a statistically significant difference between the 2 sequences for overall and for right hepatic duct and cystic channel visualization (P < 0.05). A high concordance between readers 1 and 2 both for T2-MRC and CE-MRC was achieved (85.8% and 89.4%, respectively).

Gadobenate dimeglumine can be used as an alternative intrabiliary contrast agent for contrast-enhanced MR cholangiography in nondilated biliary systems in patients with normal excretory liver function tests.

The highest rate of complications characterizing the adult living donor liver transplantation (ALDLT) are due to biliary problems with a reported negative incidence of 22-64%. We performed 23 ALDLT grafting segments V-VIII without the middle hepatic vein from March 2001 to September 2005. Biliary anatomy was investigated using intraoperative cholangiography alone in the first five cases and magnetic resonance cholangiography in the remaining 18 cases. In 13 cases we found a single right biliary duct (56.5%) and in 10 we found multiple biliary ducts (43.7%). We performed single biliary anastomosis in 17 cases (73.91%) and double anastomosis in the remaining six (26%) cases. With a mean follow up of 644 days (8-1598 days), patient and graft survivals are 86.95% and 78.26%, respectively. The following biliary complications were observed: biliary leak from the cutting surface: three, anastomotic leak: two, late anastomotic strictures: five, early kinking of the choledochus: one. These 11 biliary complications (47.82%) occurred in eight patients (34.78%). Three of these patients developed two consecutive and different biliary complications. Biliary complications affected our series of ALDLT with a high percentage, but none of the grafts transplanted was lost because of biliary problems. Multiple biliary reconstructions are strongly related with a high risk of complication.