3D-SPGR冠状位动态增强对肝占位性病变的诊断

目的:探讨MR三维扰相梯度回波序列(3 dimension-spoiled gradient recalled echo,3D-SPGR)冠状位快速动态增强对肝脏占位性病变的诊断价值。材料与方法:对26例B超、CT未明确诊断的不同大小肝占位性病变病例进行常规单次激励快速自旋回波(SS-FSE)定位、轴位自旋回波(SE)T1WI及快速自旋回波(FSE)T2WI平扫后,用3D-SPGR序列冠状位对病灶定位,行冠状位3D-SPGR序列快速动态增强扫描,分别描出病灶和正常肝实质时间-信号强度曲线,分析其强化特征并与临床、手术病理结果对照。结果:本组肝脏不同占位性病变的肿块,3D-SPGR冠状位动态增强后的强化方式、时间-信号强度曲线不同。结论:3D-SPGR冠状位动态增强对肝脏不同占位性病变具有重要的定性诊断及鉴别诊断价值。     

Non-hodgkin's lymphoma of the liver in patients with AIDS: sonographic, CT, and MRI findings

PURPOSE: We analyzed the sonographic, CT, and MRI findings in acquired immune deficiency syndrome (AIDS)-related non-Hodgkin's lymphoma (NHL) of the liver to evaluate the role of sonography in the diagnosis of this disease. METHODS: We retrospectively reviewed sonograms and CT scans on 26 patients who had human immunodeficiency virus with liver lymphoma, either primary (10 cases) or secondary (16 cases), from 1992 to 1999. We also reviewed MR images on 12 of the patients. All patients had pathologically proven NHL; all imaging studies were obtained within 2 weeks of sonographically guided fine-needle aspiration biopsies. Lymphoma was the initial AIDS-defining illness in 38% of the patients. RESULTS: NHL occurred as multiple lesions in most cases of both primary (7 of 10 cases) and secondary (15 of 16 cases) liver lymphoma. No imaging finding was specific for the diagnosis of hepatic lymphoma. The hepatic lesions were hypoechoic in 25 of 26 cases; in the remaining case, there was a large isoechoic mass. On unenhanced and contrast-enhanced CT, the lesions were hypodense in all cases, with a thin enhancing rim in 6 patients. On MRI, the lesions were hypointense on T1-weighted images and hyperintense on T2-weighted images. CONCLUSIONS: Sonography may be helpful in the diagnosis of focal hepatic lymphoma in patients with human immunodeficiency virus. Sonographically guided fine-needle aspiration biopsy provides a definitive diagnosis. CT was crucial in the staging of lymphoma. MRI appears appropriate for studying liver NHL in selected cases.     

磁共振成像与多层CT对肝脏局灶性病变定性的比较研究

目的比较综合MRI（1.5T或3T）多种序列与MSCT（16或64层）动态增强扫描对肝脏局灶性病变定性的价值。方法回顾性分析行腹部MSCT与MRI检查（两种检查间隔时间不超过1个月）且发现肝脏局灶性病变的41例患者（75个病灶）的诊断结果。结果MSCT鉴别诊断良恶性病灶的敏感度为80.77%（21/26）,特异度为68.42%（26/38）。MRI鉴别诊断良恶性病灶的敏感度为93.33%（28/30）,特异度为97.56%（40/41）。两者敏感度之间的差异无统计学意义（P=0.311）,MRI的特异度高于MSCT（P〈0.001）。对于具体的各类病灶,MRI的总体诊断准确率（86.36%,57/66）高于（P=0.004）MSCT（64.41%,38/59）。结论MRI对肝脏局灶性病变的定性能力优于MSCT。     

Giant hyperplasia of the caudate lobe of the cirrhotic liver: correlation with an anomaly of the caudate portal branch

Different imaging appearances of giant hyperplastic change of the caudate lobe of the liver are presented in a patient with liver cirrhosis. The mass like caudate lobe was isoechoic on ultrasound, hypodense on postcontrast computed tomography (CT), hyperintense on T1-weighted magnetic resonance, images and isointense on T2-weighted images. These imaging findings are similar to those of dysplastic nodule in cirrhotic liver. The caudate lobe received normal portal flow on CT during arterial portography, but superior mesenteric arteriography showed precocious or early division of the caudate portal branch. We suspect that caudate hyperplastic change may be correlated to anomalous caudate portal vein branch.     

副神经节瘤的CT和MRI表现

目的：探讨CT和MRI在副神经节瘤中的诊断价值.方法：回顾性分析26例经手术或病理证实的副神经节瘤的CT和MRI表现,所有26例均行CT扫描,16例行MRI检查.分析肿瘤的位置、大小、形态、密度、信号特点及强化方式.结果：CT表现为边界清楚或不清楚的软组织肿块,肿块呈圆形或类圆形和不规则形.平扫呈等低密度者23例,高密度者3例,增强多为持续性强化,动脉期中度-明显强化,实质期明显强化,延迟期强化程度轻度减低,24例增强后强化不均,病灶内见斑片状出血坏死区,2例强化均匀,1例病灶内有钙化,2例可见病灶周围水肿表现,1例侵犯邻近骨质.6例恶性者肿块向周围结构侵犯,伴有肝脏、双肺或淋巴结转移.肿瘤最大径线为2.5～13.5 cm（平均6.38 cm）.MRI上副神经节瘤多表现为较大软组织肿块,T1WI呈等低信号,T2WI为中等或高信号或不均匀混杂信号,DWI呈高信号,增强扫描肿瘤实质部分明显强化.结论：CT和MRI是副神经节瘤定位、定性诊断的重要影像学检查方法,CT能够很好地显示肿瘤本身及其与周围结构的关系,MRI的信号变化能够反映肿瘤组织学成分的不同,CT和MRI在早期发现病灶、副神经节瘤的诊断与鉴别、判断病灶与周围组织结构的关系方面具有重要意义.     

Magnetic resonance imaging of changes elicited by status epilepticus in the rat brain: diffusion-weighted and T2-weighted images,regional blood volume maps,and direct correlation with tissue and cell damage

The rat brain was investigated with structural and functional magnetic resonance imaging (MRI) 12 h after the arrest of pilocarpine-induced status epilepticus lasting 4 h. Histopathological data, obtained immediately after MRI analysis, were correlated with the images through careful evaluation of tissue shrinkage. Diffusion-weighted and T2-weighted imaging showed changes throughout the cerebral cortex, hippocampus, amygdala, and medial thalamus. However, only T2-weighted imaging, based on rapid acquisition relaxation-enhanced sequences, revealed in the cortex inhomogeneous hyperintensity that was highest in a band corresponding to layer V. Regional cerebral blood volume (rCBV) maps were generated using T2*-weighted gradient-echo images and an ultrasmall superparamagnetic iron oxide contrast agent. In the cortex, rCBV peaked in superficial and deep bands exhibiting a distribution complementary to the highest T2-weighted intensity. Selective rCBV increase was also documented in the hippocampus and subcortical structures. In tissue sections, alterations indicative of marked edema were found with Nissl staining in areas corresponding to the highest T2-weighted intensity. Degenerating neurons, revealed by FluoroJadeB histochemistry, were instead concentrated in tissue exhibiting hyperperfusion in rCBV maps, such as hippocampal subfields and dentate gyrus, cortical layers II/III and VI, and medial thalamus. The data indicate that:(i) T2-weighted imaging provides a sensitive tool to investigate edematous brain alterations that follow sustained seizures; (ii) rCBV maps reveal regional hyperperfusion; (iii) rCBV peaks in tissue exhibiting marked neurodegeneration, which may not be selectively revealed by structural MRI. The findings provide an interpretation of the brain response to sustained seizures revealed in vivo by different strategies of MRI analysis.     

Focal nodular hyperplasia of the liver: detection and characterization with plain and dynamic-enhanced MRI

Background: We compared nonenhanced and dynamic gadolinium (Gd)–enhanced magnetic resonance imaging (MRI) appearances of hepatic focal nodular hyperplasia (FNH) as depicted with breath-hold MR sequences and assessed the detectability of the individual MR sequences used. Methods: We retrospectively reviewed 48 consecutive patients with FNH. All patients underwent nonenhanced (T1 fast low-angle shot [FLASH] and T2 half-Fourier acquisition [HASTE]) and dynamic Gd-enhanced (T1 FLASH) MRI between December 1997 and March 2000. Individual MR sequences were analyzed separately for number of lesions, signal intensity features, dynamic enhancement pattern, and the presence and enhancement profile of a central scar. Ninety-five percent confidence intervals of absolute discrepancy were calculated to define differences in lesion detection. Results: Seventy-seven lesions were found in 48 patients. Nonenhanced FLASH imaging depicted 59 (76.6%) lesions in 45 patients. HASTE images showed 55 (71.4%) lesions in 44 patients. On T1- and T2-weighted images, lesions appeared predominantly hypointense (69.5%) and hyperintense (72.7%), respectively. Arterial and portal venous dominant phase Gd-enhanced MRI demonstrated all 77 lesions (100%), most of which showed hypervascular (94.8%), homogeneous (97.4%), and incomplete (except the central scar: 58.4%) enhancement in the arterial phase. Portal venous phase images showed lesion isointensity (50.6%) or moderate hyperintensity (46.8%) with complete enhancement (central scar: 94.8%). A central scar was detected on nonenhanced T1-weighted images (hypointense: 100%), T2-weighted images (hyperintense: 100%), arterial phase (hypointense: 59.7%) and portal venous phase (hyperintense: 71.4%) Gd-enhanced images in 78%, 69.1%, 77.9%, and 75.3% of tumors, respectively. Conclusion: Arterial and portal venous phase Gd-enhanced T1-weighted sequences are superior to nonenhanced images in the detection of FNH. Typical MRI appearances include hypointensity on T1-weighted and hyperintensity on nonenhanced T2-weighted images. Most commonly, FNH shows a homogeneous (without scar) and strong enhancement during the arterial phase, with lesion isointensity or slight hyperintensity during the portal venous phase. Received: 15 May 2001/Revision accepted: 22 August 2001     

MR imaging of malignant mesenchymal tumors of the liver

Magnetic resonance (MR) features of five primary malignant mesenchymal neoplasms (plasmocytoma, leiomyosarcoma, undifferentiated sarcoma, epithelioid hemangioendothelioma, and angiosarcoma) of the liver were reported. All tumors were hypointense on T1-weighted images and hyperintense on T2-weighted images. No halo and intravenous extension were noted. A target appearance was revealed in epithelioid hemangioendothelioma. MR findings of angiosarcoma were essentially the same as those of cavernous hemangiomas (markedly hyperintense with hypointense linear septa on T2-weighted images). MR findings of these rare hepatic malignancies were nonspecific, although they were quite different from those of typical hepatocellular carcinomas. This study suggested that MR differentiation of primary hepatic mesenchymal tumors from other common benign and malignant neoplasms was difficult; however, the number of studied cases was limited.     

SPIO-enhanced MR imaging of focal fatty liver lesions

BACKGROUND: The purpose of this study was to assess the features of focal fatty liver lesions with superparamagnetic iron oxides (SPIO) on magnetic resonance (MR) images. METHODS: We retrospectively studied five patients with six histologically proven focal fatty liver lesions who had been examined by MR with use of SPIO. The features of the focal fatty liver lesions on two T2-weighted post-SPIO-enhanced MR images, T2*-weighted fast low-angle shot (FLASH) sequences, and T2-weighted turbo-spin echo (TSE) sequences were analyzed, and the percentages of signal intensity loss of the lesions and normal liver parenchyma were calculated. RESULTS: All the fatty liver lesions exhibited different degrees of SPIO uptake, which were presented by a distinct loss of signal intensity on both post-SPIO-enhanced T2-weighted sequences. The percentage of signal intensity loss of the lesions on SPIO-enhanced images was higher than that of normal liver parenchyma in all the cases. CONCLUSION: Focal fatty liver lesions exhibit a high uptake of SPIO. The uptake is higher than that of the normal liver.     

Cavernous hemangioma arising from the lesser omentum: MR findings

We report the magnetic resonance findings of an unusual hemangioma in the lesser omentum. A well-circumscribed, large mass was identified between the stomach and the left lobe of the liver, with compression of adjacent liver parenchyma. The mass showed low signal intensity (SI) on T1-weighted images, high SI on T2-weighted images with multiple septa, and slightly decreased SI on out-of-phase T1-weighted images. After gadolinium contrast administration, septa within the mass showed minimal enhancement on 30-s T1-weighted images and mild enhancement on 5-min T1-weighted images. The mass was histopathologically diagnosed as a cavernous hemangioma comprised of multiple vascular spaces, fibrotic tissue, and adipocytes. Received: 1 December 1999/Accepted: 12 January 2000     

Squamous cell carcinoma arising from a presacral epidermoid cyst: CT and MR findings

We report CT and MRI findings in a case of squamous cell carcinoma arising from a presacral epidermoid cyst, which has not been previously reported. CT findings revealed a focal wall thickening of the anterior wall of the huge presacral cystic mass. The squamous cell carcinoma was more hypointense than the cystic fluid on T1- and T2-weighted images and showed heterogeneous enhancement on contrast enhanced T1-weighted image.     

Small hypervascular hepatocellular carcinoma versus hypervascular pseudolesions: differential diagnosis on MRI

BACKGROUND: We wanted to differentiate small hypervascular hepatocellular carcinoma (HCC) from hypervascular pseudolesion (HPL) on magnetic resonance imaging (MRI). METHODS: We reviewed small hypervascular foci (< or = 2 cm in diameter) on dynamic MRI in patients with chronic liver disease, which were followed-up with serial MRI examinations. RESULTS: Twenty of 34 hypervascular foci were larger at follow-up; 19 of 20 foci had characteristics suggesting HCC; and 14 foci did not grow or disappeared and were judged to be HPLs. There were no differences in the initial sizes and follow-up periods between HCCs and HPLs. On initial MRI, nine of 19 HCCs (47%) and one of 14 HPLs (7%) appeared hyperintense on T2-weighted images. The difference between HCCs and HPLs on T2-weighted images was statistically significant (p = 0.039). CONCLUSION: HPLs are seen frequently as small hypervascular foci on dynamic MRI in patients with chronic liver disease. Hyperintensity of the foci on T2-weighted images differentiates HCCs from HPLs.     

Unusual liver MR findings of Wilson's disease in an asymptomatic 2-year-old girl

We describe the unusual magnetic resonance (MR) findings of a case of Wilson's disease (WD) in an asymptomatic 2-year-old girl. Preenhanced computed tomography revealed multiple hyperdense areas in the liver. These lesions were hyperintense on T1-weighted and hypointense on T2-weighted MR images, results that might be ascribed to the paramagnetism of copper deposited in liver at a relatively early stage of the disease before severe liver cirrhosis had evolved. Received: 9/10/96/Accepted: 10/16/96     

Endometrial cancer: magnetic resonance imaging

Carcinoma of the endometrium is the most common invasive gynecologic malignancy of the female genital tract. Clinically, patients with endometrial carcinoma present with abnormal uterine bleeding. The role of magnetic resonance imaging (MRI) in endometrial carcinoma is disease staging and treatment planning. MRI has been shown to be the most valuable imaging mod-ality in this task, compared with endovaginal ultrasound and computed tomography, because of its intrinsic contrast resolution and multiplanar capability. MRI protocol includes axial T1-weighted images; axial, sagittal, and coronal T2-weighted images; and dynamic gadolinium-enhanced T1-weighted imaging. MR examination is usually performed in the supine position with a phased array multicoil using a four-coil configuration. Endometrial carcinoma is isointense with the normal endometrium and myometrium on noncontrast T1-weighted images and has a variable appearance on T2-weighted images demonstrating heterogeneous signal intensity. The appearance of noninvasive endometrial carcinoma on MRI is characterized by a normal or thickened endometrium, with an intact junctional zone and a sharp tumor-myometrium interface. Invasive endometrial carcinoma is characterized disruption or irregularity of the junctional zone by intermediate signal intensity mass on T2-weighted images. Invasion of the cervical stroma is diagnosed when the low signal intensity cervical stroma is disrupted by the higher signal intensity endometrial carcinoma. MRI in endometrial carcinoma performs better than other imaging modalities in disease staging and treatment planning. Further, the accuracy and the cost of MRI are equivalent to those of surgical staging.     

Detection and characterization of focal liver lesions using superparamagnetic iron oxide-enhanced magnetic resonance imaging: comparison between ferumoxides-enhanced T1-weighted imaging and delayed-phase gadolinium-enhanced T1-weighted imaging

Background: Double contrast magnetic resonance (MR) imaging using superparamagnetic iron oxide (SPIO) and gadolinium (Gd) is performed to detect and characterize focal liver lesions. However, this technique is a costly and lengthy process. The purpose of this study was to determine the usefulness of SPIO-enhanced MR imaging including SPIO-enhanced T1-weighted imaging in diagnosing focal liver lesions. Methods: Eighty-four focal liver lesions were examined with a 1.5-T MR unit. Transverse precontrast T1- and T2-weighted images and SPIO (ferumoxides)-enhanced T1- and T2-weighted images were obtained, followed by Gd-enhanced T1-weighted imaging. The Gd set (i.e., precontrast T1- and T2-weighted and delayed-phase gadolinium-enhanced T1-weighted images) and ferumoxides set (i.e., precontrast T1- and ferumoxides-enhanced T1- and T2-weighted images) were reviewed by two independent readers. Results: More lesions were detected from the ferumoxides set than from the Gd set. Ferumoxides-enhanced T1-weighted imaging showed enhancement patterns of the lesions similar to those of delayed-phase Gd-enhanced T1-weighted imaging. The diagnoses of hepatic metastasis and cyst by the ferumoxides set were similar to those by the Gd set. However, a dynamic study may be inevitable for the diagnosis of hepatocellular carcinoma and hemangioma. Conclusion: The ferumoxides set was useful for the detection of focal hepatic lesions. Ferumoxides-enhanced T1-weighted imaging may replace delayed-phase gadolinium-enhanced T1-weighted imaging in the diagnosis of hepatic metastasis and cysts.     

Magnetic resonance imaging in evaluating focal liver lesions

We report the results of magnetic resonance imaging (MRI) of the liver in 46 patients with various previously confirmed focal lesions. A characteristic signal pattern was found in hemangiomas (n = 11), with marked signal hyperintensity on T2 and proton weighted images as compared to normal liver tissue. Cysts (n = 7) also showed marked hyperintensity on T2 images, but could easily be differentiated by a lesser intensity on proton weighted images and signal hypointensity on T1 weighted images. Primary liver tumors (n = 4), metastatic liver disease (n = 18), focal nodular hyperplasia (n = 5), and liver adenoma (n = 1) revealed a weak signal hyperintensity on T2 images, with varying signals in T1 and proton weighted modalities. These data combined with other recent communications in the literature indicate that MRI is a promising diagnostic technique in the detection of focal liver lesions and that it may offer a high degree of specificity in the diagnosis of hepatic hemangiomas and benign cysts.     

Skeletal muscle metastases of hepatocellular carcinoma: A case report and literature review

BACKGROUNDThe metastasis of liver cancer to skeletal muscle is extremely rare compared to other sites. We herein report a case of rapidly developing skeletal metastases following liver transplantation due to primary liver cancer.CASE SUMMARYA 70-year-old male with underlying chronic hepatitis B virus infection was diagnosed with hepatocellular carcinoma (HCC), for which he underwent liver transplantation in 2014. Six years after receiving the transplant, pathological examination confirmed the presence of HCC without vascular invasion. He was admitted to the hospital with a rapidly growing mass on his right thigh. Ultrasound examination revealed a mixed echo mass in the lateral soft tissue of the middle part of the right femur. Magnetic resonance imaging showed heterogeneous iso-signal intensity on T1-weighted images and heterogeneous hyper-intensity on T2-weighted images compared to the surrounding muscles. Pathological examination of the ultrasound-guided needle biopsy specimen revealed that it was similar to the previously detected liver cancer; the diagnosis was metastasis of HCC. Surgical excision was performed. There were no other sites of metastasis, and the patient recovered well after surgery.CONCLUSIONThis report presents a rare case of skeletal metastasis following liver transplantation for HCC. The study suggests a possible role for skeletal muscle metastasis mechanisms, which should be the focus of future research.     

Primary MALT-lymphoma of the liver: multimodality imaging

MALT lymphoma rarely affects the liver. We present a case of primary MALT lymphoma of the liver, which appeared as multifocal hyperattenuated lesions compared to the fatty liver on unenhanced CT and as moderately hyperintense on T2-weighted and hypointense on T1-weighted MRI. We describe the radiological imaging features and discuss the differential diagnosis.     

Sarcomatoid intrahepatic cholangiocarcinoma mimicking liver abscess: A case report

Sarcomatoid intrahepatic cholangiocarcinoma(SICC)is an extremely rare and highly invasive malignant tumor of the liver.To our knowledge,the imaging findings of sarcomatous cholangiocarcinoma have been rarely reported;and radiological features of this tumor mimicking liver abscess have not yet been reported.CASE SUMMARY We present a case of SICC mimicking liver abscess.The patient,a 43-year-old male,complained of repeated upper right abdominal discomfort and intermittent distension over a period of one month.Radiology examination revealed a huge focal lesion in the right liver.The lesion was hypointense on computed tomography with honeycomb enhancement surrounded by enhanced peripheral areas.It showed a hypo-signal on non-contrast T1-weighted images and a hypersignal on non-contrast T2-weighted images.Radiologists diagnosed the lesion as an atypical liver abscess.The patient underwent a hepatectomy.After surgery,he survived another 2.5 mo before passing away.A search of PubMed and Google revealed 43 non-repeated cases of SICC reported in 20 published studies.The following is a short review in order to improve the diagnostic and therapeutic skills in cases of SICC.CONCLUSION This report presents the clinical and radiological features of SICC and imaging features which showed hypovascularity and progressive enhancement.SICC can present as a multilocular cyst on radiological images and it is necessary to distinguish this lesion from an atypical abscess.Simple surgical treatment is not the best treatment option for this disease.     

Leiomyoma of the adrenal gland in a patient with AIDS

Leiomyoma of the adrenal gland is an exceptional localization. We report a case occurring in a young patient with AIDS. Diagnosis was a surprise on pathologic examination. On enhanced computed tomographic (CT) scan, the adrenal mass had a low central attenuation area and a thin enhancing peripheral ring. On magnetic resonance (MR) imaging the left adrenal mass was isointense with the liver on T1-(TR/TE = 500/ 300 ms) and T2-(TR/TE = 2030/60, 120 ms) weighted spin-echo images, except a central area with a lower signal on T1-weighted images and a higher signal on T2-weighted images. The mass was slightly enhanced after Gd-DOTA injection, but the central area remained unchanged.