Karakas Hakki Muammer, Celik Tayfun, Alicioglu Banu
Department of Radiology, Faculty of Medicine, Turgut Ozal Medical Center, Inonu University, 44069, Malatya, Turkey.
Surg Radiol Anat. 2008 Oct;30(7):539-45. doi: 10.1007/s00276-008-0365-y. Epub 2008 May 20.
Living donor liver transplantations (LDLT) donor candidates are being assessed with MRCP (magnetic resonance cholangiopancreatography) to identify their suitability for standard surgical techniques. Variations of the bile duct anatomy play an important role in donor selection and in the selection of the resection technique. If bile duct anatomy is misrecognized, complications may occur. Anatomic variations are classified according to the origin of the right posterior hepatic duct (RPHD). According to the so called Huang classification, type A1 is the most, and type A5 is the least frequent variation. These frequencies were initially validated on Chinese population. Later studies revealed significant variability in frequency for the so called trifurcation, the variation in which a common junction of RHPD, right anterior hepatic duct (RAHD) and left hepatic duct (LHD) (A2) exists. In this study we aimed to determine the bile duct anatomy variations for the Anatolian Caucasians.
One hundred and thirty-four healthy subjects were investigated under 1.5 T MRI, with breath-hold (expiration) heavily T2-weighted turbo spin echo (TSE) static fluid imaging (TR/TE=8,000/800). The sequence has permitted three to five oblique coronal thick sections (40 mm) around a common axis. Sequences were repeated until anatomically interpretable images were obtained. Diagnostic images could not be obtained in 22 subjects. Radiologists who were fully experienced in LDLT assessment investigated these images, and classified them for the surgical variations of the bile duct anatomy.
One hundred and twelve subjects (58 men, 54 women) who were classified were between 14 and 81 years of age (mean: 39.3; SD 14.1). According to Huang classification, 61 of them (55%) were classified as type A1 (normal right and left hepatic duct junction), 16 (14%) as type A2 (common junction of RAHD, RHPD and LHD), 24 (21%) as type A3 (aberrant drainage of RPHD to left main duct), and 11 (10%) as type A4 (aberrant drainage of RPHD to main hepatic duct). When subjects, in whom the distance (d) between RPHD insertion and the right and left hepatic duct junction is less than 1 cm, are classified as type A2, the type A1 prevalence decreases to 28%. For the entire population that distance was between 3 and 25 mm (mean: 9.8, SD: 4.8). Accordingly, the frequency of type A1 anatomy was 8-29% lower than the respective frequency in Chinese population.
From the surgical perspective, close proximity (d<1 cm) of RPHD to right and left hepatic duct junction is considered as type A2 variation. According to that concept, type A1, usually accepted as the dominant anatomic variation, is encountered only in 28% of the Anatolian Caucasians. We have proposed a modified surgical classification in which Huang type 2 was subdivided into types K2a (close proximity) and K2b (trifurcating). The predominance of K2 types in the population of the study may necessitate the use of bench ductoplasty in many liver grafts.
活体肝移植（LDLT）供体候选人正通过磁共振胰胆管造影（MRCP）进行评估，以确定其是否适合标准手术技术。胆管解剖结构的变异在供体选择和切除技术选择中起着重要作用。如果胆管解剖结构被误认，可能会发生并发症。解剖变异根据右后肝管（RPHD）的起源进行分类。根据所谓的黄氏分类，A1型最为常见，A5型最为少见。这些频率最初在中国人群中得到验证。后来的研究表明，所谓的三叉型（即RPHD、右前肝管（RAHD）和左肝管（LHD）存在共同汇合处的变异）的频率存在显著差异。在本研究中，我们旨在确定安纳托利亚高加索人的胆管解剖变异情况。
134名健康受试者在1.5T磁共振成像下接受检查，采用屏气（呼气）重T2加权快速自旋回波（TSE）静态液体成像（TR/TE = 8000/800）。该序列允许围绕一个共同轴获取三到五个斜冠状厚层（40mm）图像。重复序列直至获得可进行解剖学解释的图像。22名受试者未获得诊断图像。由在LDLT评估方面经验丰富的放射科医生对这些图像进行检查，并对胆管解剖结构的手术变异进行分类。
分类的112名受试者（58名男性，54名女性）年龄在14至81岁之间（平均：39.3；标准差14.1）。根据黄氏分类，其中61名（55%）被分类为A1型（正常的左右肝管汇合处），16名（14%）为A2型（RAHD、RPHD和LHD的共同汇合处），24名（21%）为A3型（RPHD异常引流至左主肝管），11名（10%）为A4型（RPHD异常引流至肝主肝管）。当将RPHD插入点与左右肝管汇合处之间的距离（d）小于1cm的受试者分类为A2型时，A1型的患病率降至28%。在整个人群中，该距离在3至25mm之间（平均：9.8，标准差：4.8）。因此，A1型解剖结构的频率比中国人群中的相应频率低8 - 29%。
从手术角度来看，RPHD与左右肝管汇合处紧密相邻（d < 1cm）被视为A2型变异。根据这一概念，通常被认为是主要解剖变异的A1型，在安纳托利亚高加索人中仅占28%。我们提出了一种改良的手术分类方法，即将黄氏2型细分为K2a（紧密相邻）和K2b（三叉型）。本研究人群中K2型的优势可能使得在许多肝移植中需要采用体外胆管成形术。
