多层动态增强MRI技术对肝血管瘤诊断的评价

目的:研究射频毁坏傅立叶采集稳态技术(RFFAST)的动态增强及延迟增强扫描MRI对肝血管瘤的诊断价值。方法:34例肝血管瘤患者行常规MRT1WI和T2WI横断面扫描。经肘静脉团注GdDTPA0.1mmol/kg,后推入10ml生理盐水冲洗(推入时间5～6s),再行射频毁坏傅立叶采集稳态技术T1WI动态增强扫描及延迟增强扫描,分析病灶及邻近肝实质增强。结果:共发现肝血管瘤病灶67个,T1WI上呈低信号,T2WI上呈高信号;动态增强显示46个病灶呈边缘不连续的结节样强化,21个病灶呈周边不规则强化或迅速强化充填;5个病灶动态增强早期见引流静脉较早强化,14个瘤周肝实质强化。结论:磁共振成像检查中,射频毁坏傅立叶采集稳态技术T1WI动态增强扫描能够显示肝血管瘤及邻近实质强化方式,与其他成像序列结合更有利于肝血管瘤的诊断。     

肝再生性结节的MRI诊断

目的:总结肝再生性结节(RN)的MRI平扫及动态增强的表现,以与其它结节进行鉴别.方法:搜集行Gd-DTPA动态增强磁共振检查的RN病例共30例,全部病例均经手术切除病理或穿刺活检证实.MRI均行平扫、动态增强及延迟增强扫描,分析结节的信号特征及动态增强曲线.结果:肝再生性结节包括弥漫分布的小结节18例(铁质沉着性结节6例和非铁质沉着性结节12例)和大结节12例17个病灶.铁质沉着性结节在增强各期均无强化,时间-信号强度曲线较平直;大部分非铁质沉着性结节在T1WI上和T2WI上均为中等信号,周围纤维间隔为偏低信号,动态及延迟增强扫描结节轻度强化,时间-信号强度曲线与正常肝组织类似.本组所选大结节为直径大于0.5 cm、T1WI高信号、T2WI低信号的病灶,其中10个病灶(占58.8%)在T1W/WATS上信号高于T1W/IP.动态增强各期病灶无明显强化,时间-信号强度曲线显示病灶的曲线为缓慢上升型.结论:肝再生性结节有不同类型及表现形式,其中孤立的大结节型RN需与肝内其它结节鉴别.     

肝脓肿的MRI平扫及动态增强信号特征分析

目的：探讨肝脓肿的MRI平扫及动态增强扫描信号特点。方法：对临床及手术病理证实的21例肝脓肿患者MRI平扫及增强后动态扫描资料进行回顾性分析。结果：21例中,单发肝脓肿13例,多发8例,共39个主病灶,15个伴多发子灶。39个主病灶中,＂簇样征＂3个,蜂窝网格状、花边样征24个,＂环靶征＂12个。平扫示主病灶T1WI间隔及壁呈等低信号、脓腔低信号,T2WI间隔及壁略高信号、内脓腔呈更高信号;子病灶中央见点状T1WI低、T2WI高信号;20个主病灶周围见片状或肝段性T2WI高信号。增强后动态扫描：①动脉期肝脓肿27个主病灶分隔及边缘轻度强化,12个主病灶壁轻度强化、其中10个壁边缘明显强化;②门脉期分隔或/和壁强化逐渐明显、壁边缘持续强化,边界更加清晰;③延迟期（1～5min）分隔或/和壁持续强化。30min延迟扫描8个主病灶,壁内层仍见强化,壁边缘强化减退;④子病灶环边缘动脉期轻度强化、门脉期及延迟期强化逐渐明显;⑤主、子病灶坏死脓腔均无强化;⑥28个主病灶周围见片状或肝段性动脉期一过性强化。结论：MRI平扫及动态增强扫描能较好的显示肝脓肿的发生、演变、发展及转归过程,反映肝脓肿的特征表现。     

结节样周围型胆管细胞癌的CT和MRI表现

目的:分析结节样周围型胆管细胞癌(PCC)的CT和MRI表现及其病理基础.方法:15例经病理证实的结节样PCC患者,11例行多层螺旋CT平扫及动态增强扫描,6例行MRI平扫和动态增强扫描.结合病理结果分析其CT和MRI表现.结果:15例共检出病灶19个,直径(2.8±1.4)cm,于肝左、右叶均见分布.CT共检出15个病灶,增强扫描示14个病灶动脉期呈周边强化,门脉期显示8个病灶内对比剂向中央扩散强化,6个病灶未见上述强化方式;1个病灶CT动态增强扫描呈"快进快出"改变.4个病灶见邻近肝包膜凹陷,2个病灶伴随胆管轻度扩张.6例MRI共检出6个病灶,T2WI示5个病灶呈不规则低信号,动态增强扫描示相应区域均见强化;另1例病灶增强扫描动脉期有异常强化,门脉期及延迟期呈等信号.结论:结节样周围型胆管细胞癌的CT和MRI表现多样,与病灶内各种成分的比例和分布相关,其动态增强表现有一定特征性.     

动态增强MRI对眼眶海绵状血管瘤诊断及鉴别诊断的价值

目的:运用动态增强技术的MRI,分析眼眶海绵状血管瘤的强化特点,以提高对不同眼眶血管瘤的认识。材料和方法:海绵状血管瘤病例共12例,均为单发病灶,均行MRI,术后均得到病理证实。磁共振系统为Siemens公司MagnetomVisionPlus1.5T。采集线圈为头颅线圈。MR平扫包括:TSE序列的T1WI、T2WI横断面以及T1WI矢状和冠状面扫描。层厚4mm。增强检查,使用高压注射器,以2.0~2.5ml/s的速度于病人桡静脉处注射Gd-DTPA后,立即连续动态扫描7次。以观察造影剂的动态变化状况。结果:海绵状血管瘤有特殊的强化模式,表现为局部点状和小结节状强化,然后逐步向全肿瘤扩展。结论:动态增强的MRI对诊断海绵状血管瘤有重要鉴别诊断的意义。     

肝内胆管错构瘤5例的磁共振成像诊断及鉴别诊断简

目的：探讨成人肝脏胆管错构瘤的影像学表现,以提高对本病的认识。方法回顾性分析5例经手术、病理证实的肝内胆管错构瘤的影像学表现。对所有患者均行磁共振成像（MRI）平扫、磁共振胰胆管造影（MRCP）、增强扫描,并穿刺活检病理证实。结果 T1WI病变呈低于肝实质的信号,呈多发,沿血管胆管树分布, T2WI病灶显示清楚,呈明显的高信号,在MRCP序列上,多数病变显示为高信号,与T2WI比较,显示的病变数量有所减少。MRCP显示肝内多发类囊状高信号病变,与可见的胆管树不相通。增强扫描示各期病灶无强化,在增强扫描60 s,3 min肝实质明显强化,小囊状信号未见明显强化,形成明显的对比。结论成人肝内胆管错构瘤在影像学上无特征性表现,类似于肝转移瘤、肝脓肿、肝海绵状血管瘤等常见的肝囊性占位病变。     

肝胆特异性磁共振对比剂Gd-EOB-DTPA在肝脏局灶性病变诊断中的应用研究

目的:探讨Gd-EOB-DTPA MRI增强扫描时肝局灶性病变的表现及此新型对比剂的诊断效能,提高对肝脏局灶性病变的诊断准确性。方法:已知或怀疑为肝脏局灶性病变的34例患者共90个病灶,病灶性质依次为肝囊肿20个、肝细胞肝癌16个、胆管细胞癌1个、肝脏转移性肿瘤37个、肝血管瘤9个、退变结节1个、肝脏局灶性结节增生1个、肝细胞腺瘤1个、肝脏炎性病变3个及肝脏淋巴上皮瘤样癌1个。所有患者依次行MRI平扫(抑脂TSE T2WI、抑脂3DVIBE、2DGRE T1WI)、Gd-EOB-DTPA三期(动脉期、门脉期和平衡期)增强扫描(抑脂3DVIBE)及延迟20min肝实质期扫描(抑脂2DGRE T1WI、抑脂TSE T2WI、抑脂3DVIBE)。测量并分析Gd-EOB-DTPA增强前后肝脏和病灶信号变化、病灶-肝脏对比噪声比绝对值(|CNR|)变化情况,并观察病灶Gd-EOB-DTPA增强扫描表现和特征。结果:Gd-EOB-DT-PA增强后各期肝实质信号及病灶-肝脏|CNR|均显著增加(P<0.001)。动脉期、门脉期和平衡期所有病灶符合应用常规含钆(Gd)对比剂时的强化表现和特征;延迟20min肝实质期扫描时,肝脏局灶性结节增生呈等信号-高信号,1个肝细胞肝癌呈相对高信号,其余肝囊肿、肝细胞肝癌、胆管细胞癌、肝脏转移性肿瘤、淋巴上皮瘤样癌、退变结节、肝细胞腺瘤、肝血管瘤和肝脏炎性假瘤等均呈相对低信号。结论:Gd-EOB-DTPA动态增强扫描与延迟肝实质期扫描联合应用,可以提供病变形态、血供、细胞来源及功能等更多相关信息,从而提高诊断信心及诊断准确性。     

Study of clinical application of hepatic-biliary specific MR contrast agent (Gd-EOB-DTPA) in the diagnosis of focal hepatic lesions

目的:探讨Gd-EOB-DTPA MRI增强扫描时肝局灶性病变的表现及此新型对比剂的诊断效能,提高对肝脏局灶性病变的诊断准确性.方法:已知或怀疑为肝脏局灶性病变的34例患者共90个病灶,病灶性质依次为肝囊肿20个、肝细胞肝癌16个、胆管细胞癌1个、肝脏转移性肿瘤37个、肝血管瘤9个、退变结节1个、肝脏局灶性结节增生1个、肝细胞腺瘤1个、肝脏炎性病变3个及肝脏淋巴上皮瘤样癌1个.所有患者依次行MRI平扫(抑脂TSE T2 WI、抑脂3DVIBE、2D GRE T1 WI)、Gd-EOB-DTPA三期(动脉期、门脉期和平衡期)增强扫描(抑脂3D VIBE)及延迟20min肝实质期扫描(抑脂2D GRET1WI、抑脂TSE T2 WI、抑脂3D VIBE).测量并分析Gd-EOB-DTPA增强前后肝脏和病灶信号变化、病灶-肝脏对比噪声比绝对值(|CNR|)变化情况;并观察病灶Gd-EOB-DTPA增强扫描表现和特征.结果:Gd-EOB-DTPA增强后各期肝实质信号及病灶肝脏|CNR|均显著增加(P＜0.001).动脉期、门脉期和平衡期所有病灶符合应用常规含钆(Gd)对比剂时的强化表现和特征;延迟20min肝实质期扫描时,肝脏局灶性结节增生呈等信号—高信号.1个肝细胞肝癌呈相对高信号,其余肝囊肿、肝细胞肝癌、胆管细胞癌、肝脏转移性肿瘤、淋巴上皮瘤样癌、退变结节、肝细胞腺瘤、肝血管瘤和肝脏炎性假瘤等均呈相对低信号.结论:Gd-EOB-DTPA动态增强扫描与延迟肝实质期扫描联合应用,可以提供病变形态、血供、细胞来源及功能等更多相关信息,从而提高诊断信心及诊断准确性.     

肝局灶性结节性增生的影像诊断及病理对照研究

目的探讨肝局灶性结节性增生(focal nodu lar hyperp lasia,FNH)的影像学表现特点。方法经手术切除病理证实为肝局灶性结节性增生17例病例,术前均行螺旋CT平扫及动态增强扫描,其中10例又行MR平扫及动态增强扫描,分别进行影像学及病理学对照分析。结果17例FNH病灶均呈孤立结节或分叶状肿块,多数直径2~5 cm。平扫呈等或略低密度及信号,T2W I为略高信号。动态增强扫描,动脉期病灶均为明显的均质的强化,静脉期及延迟期12例仍略高于肝实质,6例略低于或等于肝实质。11例病灶内显示瘢痕,其中8例呈延迟强化。4例静脉期出现包膜样强化。病理观察:17例FNH均无包膜,增生的肝细胞形成肝板被纤维间隔分割呈结节状,瘢痕区域由纤维结缔组织及厚壁畸形血管组成。结论典型的FNH影像学可明确诊断,不典型的FNH应与肝细胞腺瘤、肝细胞癌、肝血管瘤相鉴别。     

Mn-DPDP增强MRI在肝局灶性病变中的初步应用

目的:探讨Mn DPDP增强MRI在肝局灶性病变中的应用价值。方法:搜集14例患者经临床和/或病理证 实的28个肝局灶性病变,所有病例均行常规MRT1WI、T2WI平扫和Mn DPDP增强MRI,11例患者作Gd DTPA动态 增强检查,比较3者对肝局灶性病变的检出率和诊断符合率。14例患者中1例为肝血管瘤合并肝囊肿;1例FNH;12例 肝硬化并再生结节,其中合并肝细胞癌7例,合并肝囊肿4例,合并肝细胞癌和肝囊肿1例。将每例患者不同病变分别算 为1个病灶,共计28个病灶。结果:14例患者28个病灶中,12个肝硬化结节于Mn DPDP增强后呈均匀强化,以30min ～2h内强化明显,其中3个肝硬化大结节于延迟24h扫描仍有强化,于MR平扫T1WI呈高、等信号,T2WI呈低信号, Gd DTPA增强后呈缓升速降型;8个肝细胞癌灶于Mn DPDP增强后呈不均匀带状或斑片状强化,其中5个见环状假包 膜样强化,3个延迟24h扫描仍有轻度不均匀强化,病理为高中分化型肝细胞癌,于平扫T1WI呈不均匀低、等信号,T2WI 呈不均匀高、等信号,Gd DTPA增强后呈速升速降型;1个肝血管瘤及6个肝囊肿均无明显强化;1个肝局灶性结节增生 于Mn DPDP增强后早期呈轻度不均匀强化,2h后呈等信号改变。结论:Mn DPDP增强MRI对肝局灶性病变有一定鉴 别诊断价值,但对肝硬化结节、肝细胞癌及其它     

肝海绵状血管瘤MRI动态增强表现

目的研究肝脏海绵状血管瘤MRI动态增强表现。材料与方法107例患者行MRI平扫及FL2D或SE序列动态增强扫描,分析其中的119个血管瘤的动态增强表现。结果41个血管瘤在增强早期(团注造影剂后1min内)表现为均一高信号增强,78个血管瘤表现为边缘结节状增强并逐渐向中间充填增强。SE序列扫描1.2％(1/84)的病灶延迟期呈等信号充填增强,FL2D扫描11.5％(4/35)的病灶延迟期呈等信号充填增强,余病灶均表现为高信号充填增强。结论肝血管瘤可归纳为两种增强类型快速充填型和边缘结节增强充填型。少部分血管瘤FL2D序列扫描时病灶可呈等信号充填增强。     

肝脏局灶性病变MR动态增强扫描及临床意义

目的探讨肝脏局灶性病变ＭＲ动态增强扫描方法及临床意义。方法作者前瞻性研究了１３６例肝脏局灶性病变，包括肝细胞性肝癌、周围型肝内胆管细胞性肝癌、转移瘤及海绵状血管瘤。采用平静呼吸状态下梯度回波Ｋ空间中心部分采集技术、７个连续层面８个时相动态增强扫描。结果各例均动态增强扫描成功。动态扫描显示时间信号强度曲线在肝细胞性肝癌呈速升速降型；胆管细胞癌呈渐升型；转移瘤呈环形强化，缓慢升高型；海绵状血管瘤呈速升平台型。结论平静呼吸下Ｋ空间中心部分采集肝脏动态扫描，可以显示肝脏局灶病变的血供状态，而且不同病变具有不同的强化特征。     

Hepatic Cavernous Hemangioma in Cirrhotic Liver: Imaging Findings

Objective

To document the imaging findings of hepatic cavernous hemangioma detected in cirrhotic liver.

Materials and Methods

The imaging findings of 14 hepatic cavernous hemangiomas in ten patients with liver cirrhosis were retrospectively analyzed. A diagnosis of hepatic cavernous hemangioma was based on the findings of two or more of the following imaging studies: MR, including contrast-enhanced dynamic imaging (n = 10), dynamic CT (n = 4), hepatic arteriography (n = 9), and US (n = 10).

Results

The mean size of the 14 hepatic hemangiomas was 0.9 (range, 0.5-1.5) cm in the longest dimension. In 11 of these (79%), contrast-enhanced dynamic CT and MR imaging showed rapid contrast enhancement of the entire lesion during the early phase, and hepatic arteriography revealed globular enhancement and rapid filling-in. On contrast-enhanced MR images, three lesions (21%) showed partial enhancement until the 5-min delayed phases. US indicated that while three slowly enhancing lesions were homogeneously hyperechoic, 9 (82%) of 11 showing rapid enhancement were not delineated.

Conclusion

The majority of hepatic cavernous hemangiomas detected in cirrhotic liver are small in size, and in many, hepatic arteriography and/or contrast-enhanced dynamic CT and MR imaging demonstrates rapid enhancement. US, however, fails to distinguish a lesion of this kind from its cirrhotic background.     

Mangafodipir trisodium‐enhanced MRI for the detection and characterization of focal hepatic lesions: Is delayed imaging useful?

PURPOSE: To investigate the usefulness of early and delayed hepatic MRI after mangafodipir trisodium (Mn-DPDP) administration for the detection and characterization of focal hepatic lesions. MATERIALS AND METHODS: Forty-five patients (31 males and 14 females, mean age = 61 years) with a total of 113 hepatic lesions (mean size = 3.5 cm) were included in this study (15 with hepatocellular carcinoma (HCC, N = 35), 20 with hepatic metastasis (N = 63), five with hemangioma (N = 10), three with cholangiocarcinoma (CC, N = 3), and two with liver abscess (N = 2)). T1-weighted gradient-echo MR images were obtained before and after Mn-DPDP administration, with a mean 18-hour delayed imaging. A qualitative analysis (including the size and signal intensity (SI)) and quantitative analysis (including enhancement and lesion-liver contrast-to-noise ratio (CNR)) were performed on pre- and postcontrast early and delayed MR images. RESULTS: Compared to postcontrast early imaging, 17 (48.6%) of 35 HCCs showed higher SI, 16 (45.7%) showed no SI change, and two (5.7%) showed lower SI on delayed imaging. All 63 metastases, 10 hemangiomas, three CCs, and two abscesses showed no SI change. On delayed imaging, ring enhancement was noted in 53 metastases (84.1%), three hemangiomas (30.0%), and one abscess (50.0%), but was not seen in HCCs or CCs. Eight metastases (12.7%) also showed ring enhancement on postcontrast early imaging. No newly detected hepatic lesions were revealed on postcontrast delayed MR images compared to postcontrast early images. Regarding CNR, the HCCs showed a significant increase in CNR from postcontrast early to delayed images after administration of Mn-DPDP (P < 0.01). However, none of the metastases, hemangiomas, CCs, and abscesses showed a significant increase of CNR from postcontrast early to delayed images. CONCLUSION: Postcontrast delayed MR images after Mn-DPDP administration were helpful in distinguishing hepatocellular from nonhepatocellular lesions, but were not useful for lesion detection and had limited utility for lesion characterization, since benign and malignant hepatic lesions looked the same.     

K空间中心部分采集技术肝脏局灶性病变动态增强扫描

目的：探讨Ｋ空间中心部分采集技术肝脏局灶性病变ＭＲ动态增强扫描方法及临床意义。材料与方法：前瞻性研究１１７例肝脏局灶性病变,包括肝细胞性肝癌、肝细胞性肝癌介入治疗后、周围型肝内胆管细胞性肝癌、转移瘤、海绵状血管瘤及肝囊肿。轴位常规自旋回波Ｔ１加权成像及快速自旋回波Ｔ２加权成像后,采用平静呼吸状态下梯度回波Ｋ空间中心部分采集技术、７个连续层面８个时相动态增强扫描。结果：各例均动态增强扫描成功。动态扫描显示时间信号强度曲线在肝细胞性肝癌及肝细胞肝癌介入治疗后活癌组织部分呈速升速降型;胆管细胞癌呈渐升型;转移瘤呈环形强化,缓慢升高型;海绵状血管瘤呈速升平台型;肝囊肿无强化。结论：Ｋ空间中心部分采集技术肝脏局灶性病灶动态扫描,可以在平静呼吸下成像,显示肝脏局灶病变的血供状态特征,有助于术前病灶定性诊断。     

Patterns of contrast enhancement of benign and malignant hepatic neoplasms during bolus dynamic and delayed CT

Bolus dynamic and delayed computed tomographic (CT) scans of the liver were evaluated in 43 patients with 54 hepatic hemangiomas and 111 patients with primary or secondary malignant hepatic neoplasms. Twelve patterns of contrast enhancement were recognized during the bolus dynamic phase and delayed scanning. A "typical" CT pattern for hemangiomas (present in 29 of 54 hemangiomas [53.7%]) was established: (a) diminished attenuation prior to intravenous contrast medium administration (excluding lesions arising in a liver with diffuse fatty infiltration), (b) peripheral contrast enhancement during the bolus dynamic phase, and (c) complete isodense fill-in on delayed scan images. Using these criteria, we distinguished hemangiomas from malignant neoplasms in most patients. Only one of 63 (1.6%) malignant neoplasms manifested these typical CT criteria of hemangioma. There is an 86% chance that a lesion with the typical CT appearance of hemangioma is actually a hemangioma, even when found in a patient with a known nonhepatic primary neoplasm.     

Peritumoral fat-spared area is well correlated with the presence of temporal peritumoral enhancement in hepatic hemangioma in fatty liver

PURPOSE: To assess the relationship between temporal peritumoral enhancement and peritumoral focal fat sparing adjacent to hepatic hemangiomas. MATERIALS AND METHODS: On the basis of MRI and sonographic imaging follow-up, 51 hepatic hemangiomas were identified in 37 patients, who had both hepatic hemangiomas and focal fat-sparing areas in fatty liver. Among them, 36 tumors were associated with peritumoral focal fat spares. The association between the temporal peritumoral enhancement in the early arterial phase of dynamic MRI and peritumoral fat sparing in the same hemangioma was investigated. Furthermore, the configuration of the temporal peritumoral enhancement was correlated with that of the peritumoral focal fat-sparing area. We used Chi square and Fisher's exact test for statistic analysis. RESULTS: A total of 31 out of 36 hemangiomas (86.1%) showed both peritumoral focal fat spares and temporal peritumoral enhancement. The presence of temporal peritumoral enhancement is significantly related to that of peritumoral focal fat-sparing (P < 0.001). A total of 21 of the 31 tumors (67.7%) presented with similar configuration of the peritumoral focal fat-sparing area and temporal peritumoral enhancement area with respect to size and shape. The remaining 10 hemangiomas showed similar shape but slightly different size in these two imaging characteristics. CONCLUSION: Temporal peritumoral enhancement seen in hepatic hemangioma might be related to focal fatty sparing adjacent to the hemangiomas.     

Hepatic tumors: dynamic MR imaging

Thirty-six patients with hepatic tumors (28 hepatocellular carcinomas, seven cavernous hemangiomas, one metastatic tumor) were examined with serial magnetic resonance (MR) imaging, after a bolus intravenous injection of 0.05 mmol/kg gadolinium-diethylenetriaminepentaacetic acid. A typical MR imaging pattern for hemangiomas (present in five of seven cases [71.4%]) was a lesion of diminished signal intensity on precontrast images, peripheral contrast enhancement during the bolus dynamic phase, and complete fill-in of high signal intensity on delayed scan images. Twenty-eight hepatocellular carcinomas showed a variety of contrast enhancement patterns during the dynamic phase. In 21 patients (75%), there was no area of high signal intensity within the tumor on the delayed phase. A peripheral halo with delayed enhancement was noticed in 12 patients (42.8%) Histologic correlation in hepatocellular carcinomas showed that the degree of contrast enhancement corresponded to tumor vascularity and that the peripheral halo corresponded to fibrous capsular structure.