MRI of hepatocellular carcinoma: an update of current practices

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and liver transplantation is the optimal treatment for selected patients with HCC and chronic liver disease (CLD). Accurate selection of patients for transplantation is essential to maximize patient outcomes and ensure optimized allocation of donor organs. Magnetic resonance imaging (MRI) is a powerful tool for the detection, characterization, and staging of HCC. In patients with CLD, the MRI findings of an arterial-enhancing mass with subsequent washout and enhancing capsule on delayed interstitial phase images are diagnostic for HCC. Major organizations with oversight for organ donor distribution, such as The Organ Procurement and Transplantation Network (OPTN), accept an imaging diagnosis of HCC, no longer requiring tissue biopsy. In patients that are awaiting transplantation, or are not candidates for liver transplantation, localized therapies such as transarterial chemoembolization and radiofrequency ablation may be offered. MRI can be used to monitor treatment response. The purpose of this review article is to describe the role of imaging methods in the diagnosis, staging, and follow-up of HCC, with particular emphasis on established and evolving MRI techniques employing nonspecific gadolinium chelates, hepatobiliary contrast agents, and diffusion weighted imaging. We also briefly review the recently developed Liver Imaging Reporting and Data System (LI-RADS) formulating a standardized terminology and reporting structure for evaluation of lesions detected in patients with CLD.Hepatocellular carcinoma (HCC) is a major worldwide health concern; it is the sixth most common cancer and third leading cause of overall cancer-related mortality. HCC frequently presents as a rapidly growing tumor and has historically been associated with poor prognosis and outcomes. However, tumor screening protocols in high risk patients can lead to an earlier detection of treatable disease. Screening for HCC has resulted in significant improvements in the one-year cause-specific survival rates for new patients (1), and this is directly attributed to improved survival through the detection of early stage tumor.The five-year cumulative risk of HCC ranges from 4%–30% in patients with chronic liver disease (CLD) and cirrhosis (2–3). Multiple therapeutic strategies are available for the treatment of HCC, including medical therapy, percutaneous tumor ablation, transarterial embolic therapy, surgical resection, and liver transplantation. Of all the available methods, liver transplantation is the most effective treatment for early HCC because this method removes not only the tumor but also the entire cirrhotic liver, which is at an increased risk for developing metachronous tumors. The effectiveness of liver transplantation depends upon detecting early stage disease within specific criteria. A seminal paper by Mazzaferro et al. (4), published in 1996, established the “Milan criteria” as the most widely used guidelines for transplant eligibility. The Milan transplant criteria has shown good outcomes in patients with a single tumor <5 cm, or up to three tumors but with none greater than 3 cm, without extrahepatic spread or signs of vascular invasion. These criteria yield overall and recurrence-free survival rates of 85% and 92%, respectively, at four years after orthotopic liver transplantation (4). These survival rates are similar to patients transplanted for nonmalignant indications at four years following surgery; thus, accurate staging is mandatory for proper inclusion in the transplant list.Numerous studies have been performed to investigate the diagnostic accuracy of ultrasonography (US), computed tomography (CT), or magnetic resonance imaging (MRI). In this review, we discuss MRI acquisition methodology, reporting methods and provide a discussion of the varied appearance of HCC.     

肝外胆管腺瘤的MRI表现

目的 探讨肝外胆管腺瘤磁共振表现特征,提高对肝外胆管腺瘤的诊断水平,降低其误诊率.方法 回顾性分析经手术和病理证实的5例肝外胆管腺瘤的磁共振资料.结果 5例中3例为管状绒毛状腺瘤,1例为绒毛状腺瘤,1例为管状腺瘤;5例中2例伴上皮样内瘤变,1例伴不典型增生;2例位于肝外胆管上段,1例位于肝外胆管中段,2例位于肝外胆管下段;5例病灶均呈偏心膨胀性生长.病灶信号T2WI呈等高信号3例,等信号2例;5例中3例病灶呈不规则形,2例呈类圆形;病灶边缘毛糙3例,边缘光滑2例.5例均伴有胆管扩张,且扩张的胆管壁未见增厚.结论 肝外胆管腺瘤多偏心膨胀性生长,无明显胆管壁浸润,病灶边界毛糙,T2 WI呈等或等高信号为其相对特征性表现,掌握这些MRI表现有助于提高诊断准确性.     

肾上腺皮质大腺瘤的MRI表现

目的探讨直径在4.0cm以上肾上腺皮质大腺瘤的常规MRI及扩散加权成像(DWI)表现,以提高诊断水平。方法回顾性分析经手术病理证实的15例肾上腺皮质腺瘤(≥4cm)的常规MRI表现、DWI特点及病理学表现,并与其他肿瘤进行鉴别。结果常规MRI表现:15例中,12例信号不均匀,T2WI压脂像以等高或较高信号为主,6例在梯度回波反相位上瘤体内见斑片状局灶性的信号减低区,3例在T1WI预扫见斑片状高信号区,增强扫描7例(约46.7%)呈"慢进不出"型,5例(约33.3%)呈"慢进快出"型;2例(约13.3%)呈"快进慢出"型,1例呈延迟期明显强化。实质期或延迟期肿瘤均见环形强化的完整包膜,8例见强化的纤维分隔。DWI特点:肿瘤实质扩散受限,DWI上呈高信号,表观弥散系数(ADC)图上呈低信号,平均ADC值为0.993×10-3 mm2/s,低于大多数肾上腺良性肿瘤。结论肾上腺皮质大腺瘤的病理成分复杂多样,结合其常规MRI表现和DWI特点有助于其术前定性诊断及鉴别诊断。     

Gd-EOB-DTPA-enhanced MR imaging findings of hepatocellular adenoma: correlation with pathological findings

We report a case of a 28-year-old woman with hepatocellular adenoma and correlate findings of pathology and magnetic resonance (MR) imaging with gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) enhancement. In the hepatobiliary phase, the peripheral region of the tumor that corresponded with proliferating hepatocytes with steatosis showed slight hypointensity compared with the surrounding liver parenchyma, and the central region of the tumor that corresponded with cellular areas showed isointensity.     

肝腺瘤的平扫和动态增强MRI表现

目的探讨平扫和动态增强MRI对肝腺瘤的诊断价值。方法经手术病理证实的5例单发肝腺瘤和2例糖原累积症合并多发肝腺瘤行MR检查,对病灶大小、包膜、平扫和增强信号表现进行评价。结果5例单发病灶均较大,平均6.8cm×8.9cm。与肝实质比较,T1WI序列等信号,T2WI序列高信号,病灶内见液化坏死、出血信号区,周缘见低信号包膜;增强后动脉期3例病灶明显强化,2例病灶轻~中度强化;门脉期病灶高于周围肝实质3例、等于和低于各1例;延迟期病灶高于周围肝实质1例、等于和低于周围肝实质各2例。周缘包膜门脉期和延迟期强化4例,无强化1例。2例多发病灶大小不一,MR平扫较大病灶(直径≥3cm)与上述单发病灶表现相似;小病灶(直径<3cm)相对于肝实质呈高信号或等信号,周缘基本无包膜;各病灶增强后动脉期明显强化,门脉期和延迟期高于或等于周围肝实质。结论肝腺瘤无确定一致的MRI表现,但在平扫和增强期检查的特征性表现有助于它与肝脏内其他肿瘤鉴别。     

肝细胞腺瘤的影像表现及与病理结果的对照分析

目的 探讨肝细胞腺瘤的影像特征及其相关病理基础.方法 回顾性分析经手术病理证实的12例肝细胞腺瘤患者资料,根据肿瘤的病理特性分为脂肪变性型、炎细胞浸润伴血窦扩张型、异型细胞型和不典型肝细胞腺瘤4类亚型,分析不同病理亚型肝细胞腺瘤的CT及MR表现特征并与病理结果进行对照分析.结果 脂肪变性型共4例,其中2例行CT扫描,1例行MR扫描,1例同时行CT加MR扫描.CT平扫1例,表现为低密度;增强扫描3例,动脉期、门静脉期及延迟均为低密度;MR平扫2例,T1WI正相位均为等信号,T1WI反相位均为低信号,T2 WI均为中低信号;增强扫描1例,动脉期、门静脉期及延迟期均为低信号.炎细胞浸润伴血窦扩张型共2例,均行MR扫描,1例行CT扫描;CT平扫为低密度且CT三期动态增强均表现为高密度;MR平扫2例,T1WI 1例为等信号、1例为低信号,T2WI均为中高信号,MR增强扫描,2例三期动态增强呈不均匀渐进性持续强化,均为高信号.异型细胞型共3例,CT平扫2例,1例为均匀低密度、1例为均匀等密度;CT增强扫描3例,动脉期均为高密度,门静脉期强化程度减低(2例为高密度、1例为等密度),延迟期密度进一步减低(2例呈略高密度、1例呈略低密度);1例同时行CT及MR扫描,MR平扫T1WI为等信号,T2 WI为中高信号.不典型肝细胞腺瘤共3例,1例同时行CT和MR扫描,2例仅行MR扫描.1例CT平扫为均匀低密度,增强扫描动脉期为高密度,门静脉期为等密度,延迟期为略高密度;3例MR平扫,T1WI为2例为等信号,1例为中高信号(1/3例);T2WI为中高、中低、等信号各1例;增强扫描2例,动脉期均为高信号,门静脉期呈中低、中高信号各1例,延迟期呈等信号和中低信号各1例.结论 肝细胞腺瘤的影像特征与其病理组织特征密切相关.     

结直肠绒毛状管状腺瘤的CT、MRI影像表现

目的总结结直肠绒毛状管状腺瘤的CT和MRI影像表现,旨在提高术前诊断准确率。方法搜集我院2013年1月~2018年12月经病理证实的结直肠绒毛状管状腺瘤的112例,对其影像学资料进行统计分析。结果112例中病灶位于直肠75例,结肠37例,CT和MRI扫描中病灶形态表现扁平状35例及类圆形38例,其次是分叶状25例及菜花状14例;单发病灶99例,多发13例;病灶呈宽基底与肠壁相连93例,带蒂19例。CT平扫96例呈均匀软组织密度影,增强呈持续性或渐进性不均匀明显强化85例。65例行MRI检查的患者中,平扫呈等T1稍长T2信号60例,增强呈明显不均匀强化55例,DWI呈稍高信号60例,ADC值在1~1.6×10^-3mm^2/s之间58例。结论结直肠绒毛状管状腺瘤多发生于中老年,以直肠多见,单发为主,肿瘤多表现为肠腔内类圆形、扁平状、菜花状或分叶状软组织肿块影,边界清楚,边缘光滑;CT检查平扫呈均匀的软组织密度,增强呈明显持续性或渐进性不均匀强化;MRT平扫表面见长T1长T2信号粘液覆盖,病灶增强呈中度及以上不均匀强化,MRI功能成像DWI呈稍高信号,ADC值常大于1×10^-3mm^2/s。     

肝细胞腺瘤CT与MRI的诊断价值

目的 分析肝细胞腺瘤(HCA)的CT、MRI特征性表现.方法 收集本院行CT、MRI检查并经病理证实的11例HCA患者,对所有研究对象的影像学特征进行回顾性分析比较.结果 11例中共发现18个病灶,CT平扫时均表现为低或稍低密度,其中2个病灶内可见不规则高密度区.而病灶的CT值在动脉期显著高于正常肝组织,且存在统计学差异(P<0.05).MRI扫描时2个病灶T1WI呈低或稍低信号,16个病灶呈稍高信号;14个病灶T2WI呈高信号,4个病灶呈低信号;动态增强扫描,动脉期所有病灶呈显著强化;17个病灶见假包膜强化.DWI扫描测量18个病灶,病灶的ADC值大于正常肝实质的ADC值.结论 CT三期动脉增强扫描定量分析结合MRI扫描及ADC值测量对HCA有一定鉴别诊断价值.     

Basal cell adenoma of the parotid gland: dynamic CT and MRI findings

Imaging findings in basal cell adenoma (BCA) of the parotid gland have been rarely reported. We report dynamic CT and MRI findings of BCA in the parotid gland in a 78-year-old woman. Dynamic CT study demonstrated strong multinodular contrast enhancement in the early phase which decreased gradually in the later phases. The mass was isointense on T(1) weighted and hyperintense on T(2) weighted MR images with a central haemorrhagic-necrotic component. The microscopic findings were consistent with membranous type BCA.     

MRI in local staging of rectal cancer: an update

Preoperative imaging for staging of rectal cancer has become an important aspect of current approach to rectal cancer management, because it helps to select suitable patients for neoadjuvant chemoradiotherapy and determine the appropriate surgical technique. Imaging modalities such as endoscopic ultrasonography, computed tomography, and magnetic resonance imaging (MRI) play an important role in assessing the depth of tumor penetration, lymph node involvement, mesorectal fascia and anal sphincter invasion, and presence of distant metastatic diseases. Currently, there is no consensus on a preferred imaging technique for preoperative staging of rectal cancer. However, high-resolution phased-array MRI is recommended as a standard imaging modality for preoperative local staging of rectal cancer, with excellent soft tissue contrast, multiplanar capability, and absence of ionizing radiation. This review will mainly focus on the role of MRI in preoperative local staging of rectal cancer and discuss recent advancements in MRI technique such as diffusion-weighted imaging and dynamic contrast-enhanced MRI.Colorectal cancer is the second most common cancer in women and the third most common cancer in men with 570 100 and 663 600 estimated new cases per year worldwide, respectively (1). Rectal cancer accounts for approximately 42% of colorectal cancers with 45 000 estimated new cases per year in the United States (2). Prognosis of rectal cancer is determined by depth of invasion, number of involved lymph nodes, and involvement of circumferential resection margin. Management of rectal cancer has evolved over the years with preoperative imaging playing an increasingly prominent role. Initial strategy of clinical diagnosis followed by surgery and postoperative chemotherapy had a high local recurrence rate (27%) and poor survival (48% 5-year survival) (3). Later studies showed that neoadjuvant chemoradiation improves survival and decreases local recurrence rates significantly (4). In addition, it reduces tumor size, facilitates curative resection (5), and may enable sphincter sparing surgery in cancers close to the anorectal junction (6). Neoadjuvant chemoradiotherapy is not indicated in stage I tumors (confined to rectal wall with no nodal involvement), but is recommended for stage II (extends beyond the rectal wall, no nodal involvement) and stage III tumors (regional lymph node involvement). Therefore, in order to avoid unnecessary chemoradiation in stage I cancers, a reliable imaging modality is crucial to precisely define depth of invasion and to identify lymph node involvement (7). Current approach in the management of rectal cancer includes preoperative staging with different imaging modalities followed by neoadjuvant chemoradiotherapy (for stage II/III cancers). This approach has lowered the local recurrence rate (11%) and improved survival (58% 5-year survival) (3).Preoperative imaging for rectal cancer staging is also useful to determine which surgical technique would be more appropriate: recently-developed local excision method of transanal resection or traditional radical resections such as low anterior resection or abdominoperineal resection. Physical examination, endoscopic evaluation, and imaging modalities are used for preoperative staging of rectal cancer. Ideal imaging modality should accurately assess the depth of tumor penetration (T), lymph node involvement (N), presence of distant metastatic disease (M), mesorectal fascia involvement, and anal sphincter involvement. Currently, there is no consensus on a preferred imaging technique for preoperative staging of rectal cancer.Endoscopic ultrasonography, one of the oldest and most widely used imaging modalities, is reported to assess T staging with 67%–97% accuracy and nodal involvement with 64%–88% accuracy (8–11). Although it has a role in staging of early cancers confined to the wall of the rectum, endoscopic ultrasonography may not assess deeper or higher nodes in the mesorectum and can misinterpret inflammatory or fibrotic changes as metastasis (12). Its value is also limited in the evaluation of near-obstructing tumors, tumors in the upper rectum, and mesorectal fascia involvement (12, 13).Computed tomography (CT) is commonly used in rectal cancer because of its ability to assess entire pelvic anatomy and presence or absence of distant metastasis. However, CT has limited soft tissue contrast for local staging. A meta-analysis of 83 studies showed that CT has 73% accuracy for T staging and 22%–73% accuracy for nodal staging (14). In a recent study, Sinha et al. (15) showed T stage accuracy of 87.1% and N stage accuracy of 87.1%. Although newer multidetector CT technology with multiplanar reformations has improved the accuracy, soft tissue resolution of CT is still inadequate to evaluate early rectal cancers.On the other hand, high-resolution phased-array MRI is recommended as a standard imaging modality for pre-operative local staging of rectal cancer, with excellent soft tissue contrast, functional imaging ability, and multi-planar capability (Figs. 1 and ​and2).2). With these inherent proprieties, MRI fills a gap in clinical practice and helps accurate local staging of rectal cancer prior to management decisions. This review will mainly focus on the role of MRI in preoperative local staging of rectal cancer and discuss recent advancements in MRI technique.Open in a separate windowFigure 1. a, b.Axial (a) and coronal (b) fast spin-echo T2-weighted MR images obtained with a phased-array coil on a 3.0 T magnet show the normal anatomy of the pelvis. The rectum (a, arrowhead) is distended with water. Note uterus (a, arrow), and oval-shaped fatty-centered left iliac node (a, curved arrow), which is likely reactive. The iliococcigeal part of the levator ani muscle (b, arrows) extends from the pelvic sidewalls to the anus and joins with the puborectalis muscle (b, arrowheads) to form the external sphincter of the anus (b, curved arrow).Open in a separate windowFigure 2.Axial T2-weighted MR image obtained with an endorectal coil shows the layers of the rectum. Hyperintense submucosa (curved arrows) is surrounded by hypointense muscularis propria (arrows). The mucosa cannot be differentiated from the submucosa, and both layers appear as a single hyperintense layer. Note the levator ani muscle (curved arrows).     

Two cases of adrenal hemangioma: CT and MRI findings with pathological correlations

We present two cases of adrenal hemangioma, a rare non-functioning adrenal tumor, and correlate the CT and MR imaging findings with the pathological findings. Peripheral spotty contrast enhancement with centripetal enhancement was noted in one case. This pattern of enhancement is crucial for diagnosing adrenal hemangioma. The other case showed only thin rim enhancement without centripetal enhancement. This finding can be seen in other adrenal tumors, making diagnosis difficult. Marked hyperintensity on T2-weighted images and focal hyperintensity on T1-weighted images that showed focal hemorrhage and calcification were noted. These findings can also be seen in other adrenal tumors and are not pathognomonic of adrenal hemangioma. However, observing the combination of these findings can lead to the correct diagnosis.     

Diagnostic approach in multiple sclerosis with MRI: an update

Although neurological examination and medical history are the first and most important steps towards the diagnosis of multiple sclerosis (MS), MRI has taken a prominent role in the diagnostic workflow especially since the implementation of McDonald criteria. However, before applying those on MR imaging features, other diseases must be excluded and MS should be favoured as the most likely diagnosis. For the prognosis the earliest possible and correct diagnosis of MS is crucial, since increasingly effective disease modifying therapies are available for the different forms of clinical manifestation and progression. This review deals with the significance of MRI in the diagnostic workup of MS with special regard to daily clinical practice. The recommended MRI protocols for baseline and follow-up examinations are summarized and typical MS lesion patterns (“green flags”) in four defined CNS compartments are introduced. Pivotal is the recognition of neurological aspects as well as imaging findings atypical for MS (“red flags”). In addition, routinely assessment of Aquaporin-4-IgG antibodies specific for neuromyelitis optica spectrum disorders (NMOSD) as well as the knowledge of associated lesion patterns on MRI is recommended. Mistaken identity of such lesions with MS and consecutive implementation of disease modifying therapies for MS can worsen the course of NMOSD.     

Breast MRI: an illustration of benign findings

Despite its unparalleled sensitivity for aggressive breast cancer, breast MRI continually excites criticism for a specificity that lags behind that of modern mammographic techniques. Radiologists reporting breast MRI need to recognise the range of benign appearances on breast MRI to avoid unnecessary biopsy. This review summarises the reported diagnostic accuracy of breast MRI with particular attention to the technique’s specificity, provides a referenced reporting strategy and discusses factors that compromise diagnostic confidence. We then present a pictorial review of benign findings on breast MRI. Enhancing radiological skills to discriminate malignant from benign findings will minimise false positive biopsies, enabling optimal use of multiparametric breast MRI for the benefit of screening clients and breast cancer patients.     

MRI findings of recurrent hepatocellular carcinoma after liver transplantation: preliminary results

Purpose

To describe the patterns of recurrence and serial magnetic resonance imaging (MRI) features of hepatocellular carcinoma (HCC) after liver transplantation.

Materials and Methods

All cases of recurrent HCC after transplantation between September 2002 and August 2009 that underwent MRI including precontrast T1, T2‐weighted images, and postgadolinium dynamic images were reviewed. On MRI we evaluated the characteristics and patterns of recurrent HCC after transplantation.

Results

A total 7 of 76 transplanted patients (four men, three women, age range, 45–63, mean 52.7 years) were included in this study. Four patients (57.1%) were identified to have a pattern of persistent local disease (PLD) near the transplanted liver, hepatorenal space, or suture site within 2.75 years (range, 2–4 years). Two patients showed recurrent HCC in the allograft alone within 5 years. One patient showed an intraperitoneal seeding (IPS) pattern which demonstrated diffuse peritoneal infiltration and thickening within 9 months. The diffuse metastatic disease (DMD) pattern was observed as a late manifestation of PLD and IPS. The most prominent volume of recurrent tumor burden was found in an extrahepatic (5 of 7 patients) compared to an intrahepatic (2 of 7 patients) location. The signal intensities and enhancement patterns did not exhibit change with disease progression.

Conclusion

We describe four patterns of recurrence of HCC following transplant. The most prominent tumor burden was located in an extrahepatic compared to an intrahepatic location. J. Magn. Reson. Imaging 2011;33:1399–1405. © 2011 Wiley‐Liss, Inc.     

腮腺基底细胞腺瘤的CT与MRI表现

目的:探讨腮腺基底细胞腺瘤(BCA)的CT和MRI表现。方法:回顾性分析10例腮腺BCA的CT和MRI表现。10例中男3例,女7例;右侧腮腺4例,左侧6例。结果:10例肿瘤均为单发,肿瘤最长径平均为2.4cm。10例肿瘤中不规则形或深分叶状2例,圆形或类圆形8例;边缘均光滑清楚。MRI检查2例,表现为长T1、短T2信号实性肿块,伴稍低信号包膜,增强扫描后病灶呈均匀明显强化。CT检查8例:6例呈实性,2例呈囊实性、内有大片液化囊变,实性部分明显强化。结论:腮腺BCA的CT和MRI表现有一定特征,结合临床,有助于本病的诊断和鉴别诊断。     

MRI of a pituitary cryptococcoma simulating an adenoma

We describe a rare pituitary cryptococcoma in an immunocompetent patient, with radiological features similar to those of a pituitary macroadenoma. Although unusual, it should be added to the list of differential diagnosis of pituitary masses. Contrast enhancement of adjacent meninges differentiated the lesion from an adenoma.     

混合型肝癌的CT和MRI表现

目的 探讨混合型肝癌的CT及MR表现.方法 回顾性分析23例经手术病理证实的混合型肝癌的CT和MRI表现.18例行CT平扫和动态增强扫描,5例行MR平扫和动态增强扫描,观察其影像特征.结果 18例行CT检查的患者平扫表现为边界不清楚的低密度肿块(15例),并有淋巴结肿大(5例)、血管侵犯(7例)、卫星灶(5例)、假包膜(9例)、肝内胆管扩张(1例)等恶性肿瘤的特征;5例行MR检查的患者平扫T1WI序列上表现为低或略低信号,T2WI序列表现为高或略高信号,1例伴有淋巴结肿大,1例伴有血管侵犯,4例伴有假包膜.在CT、MR的动态增强上,大部分肿瘤在动脉期表现为肿瘤内部或周边不均匀强化,在静脉期肿瘤部分区域可见不均匀性高密度或信号(在动脉期图像上相对应为低密度信号区),延迟期仍可见对比剂潴留而呈高低混杂密度或信号.结论 平扫和动态增强CT及MR扫描能反映混合型肝癌的影像特点,具有一定特征性,有助于提高该病的诊断准确性.