螺旋CT双期或三期扫描对肝脏占位性病变的诊断

目的：分析肝脏螺旋CT双期或三期扫描表现，探讨其对原发性肝癌、肝转移瘤、肝血管瘤的诊断及鉴别诊断的意义。方法：经临床证实25例，均作螺旋CT平扫、动脉期、门脉期及部分平衡期和延迟期扫描，并分析螺旋CT多期扫描表现。结果：原发性肝癌动脉期明显强化而肝脏无强化，形成鲜明的对比，门脉期呈相对低密度或恢复到平扫时表现。肝血管瘤CT特征为动脉期呈边缘性环状、结节样强化，门脉期病灶边缘强化向中心强化并充满病灶呈高密度，平衡期呈等密度或低密度肝转移瘤表现多样化，周边强化或不均匀强化或不强化。结论：螺旋CT双期或三期扫描已作为对肝脏占位性病变的主要检查方法，并作为常规。     

16层螺旋CT肝脏多期扫描的方法与实用价值

目的:探讨16层螺旋CT肝脏多期扫描的方法及应用价值。方法:150例疑有肝脏病变的患者行16层螺旋CT多期扫描。层厚7.5mm,螺距1.375,扫描时间0.8s/r,静脉团注对比剂80～120ml,分别延时23～28s、45～50s58～65s行肝动脉期(动脉早期)、门静脉流注期(动脉晚期)和肝静脉期(实质期)扫描,并对图像作回顾性分析,比较增强前后腹主动脉、门静脉、肝静脉的CT值变化和后处理图像显示肝动脉、门静脉、肝静脉的能力。结果:16层螺旋CT肝脏多期扫描,肝脏血管增强后与增强前的密度差在91.9HU以上,VR、MIP、MPR图像上100%显示肝动脉(150/150),门静脉显示率为96.7%(145/150),肝静脉显示率为95.3%(143/150)。5例门静脉显示不清的病例中,3例为肝癌合并肝门区淋巴结转移,1例肝癌合并门静脉癌栓形成,1例为严重肝硬化合并腹水、脾肿大;7例肝静脉显示不清中有5例与门静脉显示不清的5例为相同病例,其余2例为严重肝硬化合并腹水。结论:16层螺旋CT肝脏多期扫描对评估肝脏病变、肝脏血管的正常、变异以及病变对血管的影响有很大帮助,但是对于严重肝硬化门静脉高压、门静脉狭窄、门静脉血栓(包括癌栓)形成的病例,显示门静脉和肝静脉不理想。     

多层螺旋CT三期增强扫描对胰腺癌诊断价值

目的：评价多层螺旋CT多期增强扫描对胰腺癌的诊断价值。方法：48例胰腺癌患者行多层螺旋CT多期扫描，先作平扫，再以3ml/s的速度通过肘静脉团注对比剂(碘海醇)90～100ml，分别行动脉期(注射后25～25s)，门脉期(70～85s)及平衡期(180～200s)扫描，层厚5mm。分别观察平扫及增强各期正常胰腺的形态、密度的变化，胰腺癌的形态、密度的变化以及转移瘤的发现率。结果：多层螺旋CT扫描速度快，检查时间短，密度分辨率高，可在一次屏气下完成腹部的CT扫描。正常胰腺血供丰富，增强时动脉期、门脉期强化很明显，而胰腺癌为相对乏血管，增强时动脉期、门脉期强化不明显，呈低密度区，动脉期扫描正常胰腺和癌肿的密度差异较大，门脉期及平衡期可兼顾显示胰腺癌及胰外转移瘤。结论：胰腺癌的多层螺旋CT检查应以三期增强扫描作为常规，动脉期对胰腺癌特别是小胰腺癌的诊断有重要的价值。     

肝细胞癌门静脉癌栓致肝脏灌注异常CT表现

目的：探讨肝细胞癌合并门静脉癌栓致肝脏灌注异常螺旋CT动、门脉双期增强表现特征,以利于准确判断癌灶的范围肝脏血流动力学异常等。材料与方法：1998年4月至2000年7月因肝细胞癌行肝脏螺旋CT动、门脉双期增强扫描的连续性病例245例,随机选择其中门静脉左支、右支或/和主干癌栓的病例共36例作为研究组,并随机选择同期无门静脉癌栓的肝细胞癌36例作为对照组。全肝平扫后,分别于开始注射对比剂后20s、60s行全肝螺旋CT双期扫描。观察平扫、动脉期、门脉期非癌变肝组织、癌灶、门静脉的密度变化。结果：门静脉癌栓发生部位：右支16例,左支4例,右支及主干10列,左、右支及主干6例。动脉期扫描非癌变肝组织高灌注15例,表现为不规则斑片状或三角形均匀性高密度区,门脉期扫描该区域密度与其他部位非癌变肝组织密度一致或略低。门脉期扫描发现异常灌注9例,表现为不规则斑片状或三角形低密度区。结论：门静脉癌栓是引发肝实质灌注异常的重要原因之一,由乙肝病毒感染所致肝硬化较少引起肝实质局灶性灌注异常。螺旋CT动、门脉双期增强扫描,有利于发现肝实质灌注异常、准确判断癌灶的范围。     

硬化型肝癌的螺旋CT多期扫描表现

目的：分析总结硬化型肝癌的螺旋CT多期扫描表现，以进一步提高对该病的诊断准确性。材料和方法：经手术证实的7例硬化型肝癌患者行螺旋CT平扫和多期增强扫描。注射造影剂后30s开始动脉期扫描，70s开始门脉期扫描，另有4例加做3—4min的延迟期扫描，观察病灶的强化方式。结果：平扫7个病灶均为低密度。动脉期6个病灶有轻度的不规则环形、点状或结节状强化，1例无强化。门脉期7个病灶均有不同程度的强化，如不规则环形强化、边缘结节状强化或中心强化等，强化范围较动脉期增大。延迟期4个病灶仍有各种各样的强化表现。结论：硬化型肝癌的螺旋CT多期扫描表现特殊，以早期轻度强化、门脉期和(或)延迟期仍有持续强化为主，需认真与血管瘤及炎性假瘤鉴别，了解其CT表现有助于临床正确诊断和治疗方案的选择。     

螺旋CT多期增强扫描对平扫为等密度的肝细胞癌的诊断

目的 分析平扫为等密度的肝细胞癌(hepatocellular carcinoma,HCC)的螺旋CT( spiral CT,SCT)多期增强扫描表现,探讨SCT多期增强扫描对此类HCC的诊断价值.方法 收集本院经手术病理、肝穿刺活检或临床随访证实的CT平扫呈等密度的HCC 14例(占同期702例HCC的1.99%),回顾性分析这类HCC 的SCT多期增强扫描的强化方式及CT征象.结果 14例HCC 的SCT平扫均呈等密度影(假阴性).SCT多期增强扫描表现为"速升速降"型强化的4例,3例可见肿瘤假包膜形成;动脉期仍为等密度,门脉期及延迟期呈低密度影的4例;动脉期、门脉期和延迟期癌灶均呈低密度影的2例;动脉期瘤灶明显强化,门脉期、延迟期表现为等密度的3例;平扫为等密度、多期增强扫描显示动静脉瘘及门静脉癌栓的弥漫型肝细胞癌1例.结论 CT平扫可能会漏诊等密度的肝癌病灶,可疑患者需行增强扫描检查;SCT多期增强扫描能显示平扫为等密度的HCC的血供特点,对其具有重要的诊断价值.     

64层螺旋CT多期扫描双动脉期诊断小肝癌的价值探讨

目的 评估64层螺旋CT双动脉期扫描对小肝癌的诊断价值.方法 23例(25个病灶)小肝癌患者,经64层螺旋CT双动脉期、门静脉期三期增强扫描.采用对比剂追踪触发技术启动动脉早期扫描,触发监测点设为腹腔干层面的降主动脉,触发阈值140 HU,触发后延迟5 s开始动脉早期扫描,延迟20 s开始动脉晚期扫描,动脉早期与动脉晚期扫描分别屏气进行;门静脉期扫描用固定的延迟70 s;每次全肝扫描的时间为4～5 s.测量各期病灶与肝脏(同层面肝实质)的密度差值(取CT值差值的绝对值);分析与统计动脉早期、动脉晚期及门静脉期对病灶的检出率. 结果动脉早期及动脉晚期病灶与肝脏密度差值的差异有显著统计学意义(P<0.01);动脉早期检出率(11个,44.0%)低于动脉晚期(19个,76.0%);双动脉期加门静脉期检出率(25个,100%)高于动脉晚期加门静脉期(21个,84.0%)及动脉早期加门静脉期(15个,60.0%).结论 64层螺旋CT双动脉期及门静脉期多期扫描提高对多血供小肝癌的检出率.     

小肝癌螺旋CT多期扫描不强化的病理基础探讨

目的:分析螺旋CT多期扫描诊断小肝癌的价值,从而探讨少数小肝癌不强化的病理基础。方法:52例小肝癌(SHCC)患者行螺旋CT平扫和多期增强扫描,平扫后分别行动脉期、门脉期和延迟期增强扫描,观察病灶的强化形式。手术病理记录肝脏有无肝硬化、坏死囊变、透明细胞变及脂肪变性等。结果:52例患者共发现病灶72个,CT动脉期扫描有48个病灶有明显强化。SHCC在CT动脉期-门脉期-延迟期扫描中的典型方式为高-低-低密度等高-等-低密度;不典型方式为低-低-低密度和高-等-等密度。术中见肝硬化者占79.2%,18.1%的病灶内见出血坏死,16.7%的病灶出现透明细胞变或全灶为透明细胞癌。结论:大部分小肝癌在动脉期出现强化,多期扫描不强化的占11.1%,不强化主要是坏死造成,脂肪变性和透明细胞变性也是主要原因之一。     

胆囊癌的多层螺旋CT表现

目的探讨胆囊癌的多层螺旋CT表现。方法分析28例经病理证实的胆囊癌多层螺旋CT平扫和三期增强扫描的强化特点。结果本组28例胆囊癌与肝实质强化比较,平扫等密度23例,低密度5例,在动脉期呈低密度3例、等密度4例、高密度21例,在门脉期呈等密度22例,高密度6例,在平衡期呈等密度24例、高密度4例。肿瘤表现为壁局限性增厚(17例),腔内结节(6例),腔内肿块(5例)。结论胆囊癌主要表现为胆囊壁局限性不规则增厚和腔内结节,在平扫主要呈等密度,增强扫描强化显著,并具有延迟强化的特点,这些特点对于诊断和鉴别诊断有很高价值。     

肝炎性假瘤16层螺旋CT表现分析

目的 研究肝炎性假瘤(IPL)的16层螺旋CT平扫及动态增强扫描表现. 方法 回顾性分析16例肝炎性假瘤的CT平扫及动态增强扫描表现,分别测量病灶及病灶周边肝组织的平扫及增强扫描各时相CT值,并对其进行比较. 结果 16例患者共发现18个病灶,病灶大多位于肝右叶,CT平扫表现为圆形、类圆形或不规则形状低密度影.增强扫描动脉期表现为无或仅为轻度强化,门脉期表现为轻到中度强化,部分病灶表现周边肝组织环形强化,或(及)病灶中心结节状或纤维条索状强化或(及)门静脉分支穿过病灶等特征性改变.统计学提示IPL病灶在动脉期的CT值增加与平扫比较不存在统计学差异(P＞0.05),门脉期的CT值增加与平扫及动脉期比较均存在统计学差异(P＜0.05);而病灶周边区域肝组织在平扫、动脉期及门脉期的CT值两两比较均存在统计学差异(P＜0.05).结论增强CT动态扫描显示IPL病灶整体呈少血供表现,以门脉期及延时期的CT表现最具特征性.     

肝癌药物碘油栓塞术常见并发症

本文报道44例肝癌行82次药物碘油栓塞术所见的并发症及处理。一般反应有术中迷走神经反射,术后栓塞综合征。严重的并发症主要有术后消化道大出血3例:肝癌破裂引起腹腔内及消化道大出血1例;严重感染3例。对消化道及肝癌破裂出血者,作者采用导管动脉灌注血管收缩剂或动脉栓塞止血获得良好效果。     

Assessment of vascular physiology of tumorous livers: comparison of two different methods

RATIONALE AND OBJECTIVES: To evaluate liver and liver tumor perfusions by using two different modelling methods: gamma-variate fitting and a single-compartment model. MATERIALS AND METHODS: 5 New Zealand White rabbits with VX2 tumor implanted into the liver via portal injections were studied. Contrast-enhanced functional CT (fCT) examinations with temporal resolution of 200-500 milliseconds were conducted before tumor inoculation. Thereafter, two or three follow-up studies were conducted. A gamma-variate fitting method was used to determine fractional blood volumes (BV), and a single-compartment model method was used to determine fractional blood volumes (BV), blood flows (BF), and mean transit times (MTT) for normal and tumorous liver regions. RESULTS: For tumorous regions in liver, the gamma-variate fitting and the single-compartment model methods showed statistically significant increases in arterial perfusions (P < 0.01) and decreases in portal perfusions (P < 0.01 with single-compartment model, and P < 0.05 with gamma-variate fitting) when compared with normal liver regions. The single-compartment model showed statistically significant increases (P < 0.01) in MTTs in tumorous regions. In normal liver regions, portal BFs decreased and MTTs increased after tumor inoculation, but the changes were statistically not significant. CONCLUSION: The gamma-variate fitting and the single-compartment model methods showed definite differences in perfusions between normal and tumorous regions in liver. The single-compartment model showed slightly more distinction and was faster. More importantly, both methods can easily be applied in the clinical environment in the assessment of liver perfusion.     

Solitary Necrotic Nodules of the Liver Mimicking Hepatic Metastasis: Report of Two Cases

We present two cases of solitary necrotic nodules of the liver which on radiologic images mimicked hepatic metastasis. Solitary necrotic nodule of the liver is a rare but benign entity which histopathologically consists of an outer fibrotic capsule with inflammatory cells and a central core of amorphous necrotic material. The lesion was seen on contrast-enhanced CT as an ovoid-shaped hypoattenuating nodule; on CT during hepatic arteriography as enhancing nodule; on intraoperative US as a target-appearing hypoechoic nodule; on T2WI as a hyperintensity nodule, and on dynamic MR as a subtle peripheral enhancing nodule. Although the radiologic features are not specific, solitary necrotic nodule of the liver should be included in the differential diagnosis of hepatic metastasis.     

Liver transplant rejection and cholestasis: comparison of technetium 99m-diisopropyl iminodiacetic acid hepatobiliary imaging with liver biopsy

To determine whether the scintigraphic evaluation of technetium-99m diisopropyl iminodiacetic acid (DISIDA) uptake and excretion can distinguish among liver transplant patients with biopsy evidence for rejection, cholestasis or neither condition, we reviewed scintigrams and biopsies in 36 patients. There were 76 scintigrams with corresponding biopsies. Uptake and excretion were graded from image data on scales reflecting normal through severely abnormal values. Biopsies were evaluated for findings of cholestasis and rejection. The majority of scintigrams demonstrated normal uptake (60/75, 80%) and delayed excretion (65/76, 85%), which was most marked immediately after transplantation. One-way analysis of variance showed that the mean excretion values significantly differed between patients with normal biopsies and those with cholestasis and/or rejection (P =0.0003). However, mean uptake scores demonstrated no statistically significant difference between these two groups of patients (P =0.1). These findings suggest that ^99mTc-DISIDA scintigraphy can differentiate between transplants with and without rejection/cholestasis but not between rejection and cholestasis. If ^99mTc-DISIDA excretion is normal, rejection and cholestasis are unlikely. Offprint requests to: C.M. Engeler     

Uptake of technetium 99m MDP by hepatoblastoma

Focal uptake of ^99mTc-MDP was seen in a case of hepatoblastoma. The focal uptake corresponded to an area of calcification on CT, which was shown histologically to consist of osteoid with mineralization. The mechanism of uptake by the tumor in this case is likely to be the same as for skeletal uptake.     

Imaging of metastases to the liver

Metastatic disease to the liver is an important disease from the diagnostic, prognostic and therapeutic points of view. Different imaging modalities, such as US, CT, scintigraphy, and MRI, have been used for detection, characterization, therapy planning, and follow-up of this disease with variable degrees of success and failure. This review handles the problems which face the different imaging modalities in diagnosis of liver metastases in view of the pathological background of the disease. It also discusses the indications, strong points, and shortcomings of each of the imaging modalities in diagnosis of metastases, and surveys the recent efforts done to improve their performance through the optimization of quality control and in the innovations in the field of contrast agents. Finally, a protocol is suggested for the clinical management of patients with liver metastases to optimize cost-effectiveness of the imaging modalities in this era of multimodality approach in diagnostic imaging. Correspondence to: D. Mathieu     

Extrahepatic spread of hepatocellular carcinoma: a pictorial review

Although extrahepatic spread of hepatocellular carcinoma (HCC) is uncommon, it can be found anywhere in the body. Most extrahepatic metastases of HCC occur in patients with advanced-stage intrahepatic tumor, but incidental extrahepatic lesions have also occasionally been found in patients with early-stage intrahepatic HCC. The detection of extrahepatic metastatic disease is crucial when planning therapy for patients with HCC and should be used to avoid unnecessary surgical intervention. In this study we illustrate the radiologic findings of extrahepatic metastases of HCC involving various sites. The presumed mechanism of extrahepatic extension of HCC is also discussed. Electronic Publication     

Focal Nodular Hyperplasia with Retraction of Liver Capsule: A Case Report

Focal nodular hyperplasia (FNH) is characterized by the presence a central scar with radiating fibrous septa. Our case had a capsular retraction, which was the result of an extension of the central scar to the surface. In addition, a hypointense scar on the T2-weighted image and a minimal enhancing central scar on the enhanced T1-weighted image, which was due to dense, sclerotic collagenous tissue, were observed. We report the first case of FNH with a capsular retraction.     

Carcinosarcoma of the Liver: A Case Report

Primary hepatic carcinosarcoma is a rare tumor comprised of a mixture of carcinomatous and sarcomatous elements. Less than 20 adequately documented cases have been reported, however the imaging features of two cases were briefly described. We present here a case of carcinosarcoma of the liver in a 46-year-old woman, which was confirmed based on pathology. Imaging showed a large mass with large necrotic portions, small cystic portions, calcifications and bone formations.