颅内多发原发性肿瘤的CT与MRI诊断

目的：报道１５例颅内多发原发性肿瘤的ＣＴ和ＭＲＩ表现，并评价ＣＴ与ＭＲＩ的诊断价值。方法：１５例颅内多发原发性肿瘤均行ＣＴ检查，其中４例行ＭＲＩ检查，均经手术病理证实。结果：多发胶质瘤４例，其中恶性室宫膜瘤３例，表现为脑室内及额顶叶脑实质内实质性肿块或囊性病变，多发星形细胞瘤１例，病变分别位于额叶及小脑蚓部；双侧听神经瘤及多发脑膜瘤各３例、ＣＴ和ＭＲＩ表现均较典型；脑膜瘤合并胶质瘤３例、脑膜瘤合并听神经瘤１例和垂体瘤合并胶质瘤１例。结论：结合肿瘤的ＣＴ和ＭＲＩ表现特点，可对大多数颅内多发原发性肿瘤作出正确诊断，ＭＲＩ对脑膜瘤的诊断优于ＣＴ。     

椎管内肿瘤MRI诊断

目的：根据椎管内肿瘤的ＭＲＩ表现和病理基础，对肿瘤定位、定性和鉴别诊断进行探讨。材料与方法：选择８４例经手术病理证实的椎管内肿瘤，观察肿瘤形态、边界、ＭＲＩ信号特征、强化程度及与周围脊髓、硬膜囊、椎体附件的关系。结果：髓内肿瘤脊髓径线增大为主，其中室管膜瘤以瘤体内空洞和周边含铁血黄素沉着所致低信号线为其特征，髓外硬膜下肿瘤有硬膜下征改变，神经鞘瘤较易形成囊变和椎管外侵犯。硬膜外肿瘤多有硬膜外征表现     

颈静脉球瘤的CT和MRI诊断

目的：探讨ＣＴ和ＭＲＩ检查在颈静脉球瘤诊断、鉴别诊断及手术径路选择中的作用与价值。材料和方法：５例经手术证实的颈静脉瘤患者，术前均行ＣＴ增强前后扫描，４例行ＭＲＩ平扫及增强后成像。分析ＣＴ和ＭＲＩ的不同表现，比较其优缺点，并介绍分型与手术径路的关系。结果：按Ｇｌａｓｓｃｏｃｋ－Ｊａｃｋｓｏｎ＇ｓ分类法，其中Ⅰ型１例，Ⅱ型１例、Ⅲ型２例、Ⅳ型１例。ＣＴ能清晰地显示颅底骨质结构的破坏程度及范围，颈静脉孔的扩大以及边缘不规则的侵蚀性破坏是颈静脉球瘤的特征性表现。ＭＲＩ能更准确地显示肿瘤的大小、与颈内动脉、颈内静脉的关系以及有无颅内侵犯、侵犯的程度。肿瘤内迂曲的流空血管及＂椒一盐＂征是颈静脉球瘤的特征性ＭＲＩ表现，结论：ＣＴ和ＭＲＩ结合，能更全面地提供临床诊断及治疗所需的信息，为治疗方法的选择提供可靠的依据。     

原发性椎管内肿瘤的MRI诊断价值

目的：评价ＭＲＩ对原发性椎管内肿瘤的诊断价值。材料和方法：对６３例原发性椎管内肿瘤进行ＭＲＩ扫描，并与手术病理和临床随访结果对照分析。结果：检出神经纤维瘤及神经鞘瘤２７例，脊膜瘤１１例，髓内胶质瘤１４例，蛛网膜囊肿６例，皮样囊肿２例，淋巴瘤２例，脂肪瘤１例。与ＣＴ和脊髓造影等检查相比，ＭＲＩ对本病的检出率和诊断正确率明显提高。结论：ＭＲＩ是发现原发性椎管内肿瘤的首选方法，对本病的诊断与鉴别诊断具有重要价值。     

颈静脉孔区肿瘤的MRI和MRA诊断（附五例报告）

目的：分析颈静脉孔区肿瘤的影像学特点，探讨ＭＲＡ对其诊断与鉴别诊断的价值。材料与方法：对５例经手术病理证实的颈静脉孔区肿瘤（颈静脉球瘤２例、神经鞘瘤２例、脑膜瘤１例）病人行ＭＲＩ和ＴＯＦ法ＭＲＡ检查，应用１．０Ｔ超导ＭＲ系统，在常规ＭＲＩ基础上采用２Ｄ或３ＤＦＩＳＰ序列和ＭＩＰ图像后处理技术获取ＭＲＡ图像。４例有ＣＴ，３例有ＤＳＡ资料。结果：ＭＲＩ显示了全部病灶和颈静脉孔的扩大与破坏，准确定性诊断了４例，结合ＭＲＡ后，５例均正确定性诊断。颈静脉球瘤的ＭＲＩ瘤内流空征和ＭＲＡ血管团块征颇具特征性。神经鞘瘤与脑膜瘤的ＭＲＩ信号有别，且前者易囊变，两者ＭＲＡ均未显示肿瘤血管。结论：ＭＲＩ，尤其结合ＭＲＡ对颈静脉孔区肿瘤诊断与鉴别诊断颇有价值。     

MRI显示四肢原发恶性骨肿瘤范围的价值

目的：评价ＭＲＩ显示四肢原发恶性骨肿瘤范围的价值。材料与方法：对比分析１７例经手术病理证实的四肢恶性骨肿瘤的平片、ＣＴ和ＭＲＩ表现，并将ＭＲＩ所见与相应大体病理标本的断面对照分析。结果：显示肿瘤病灶纵向范围，ＭＲＩ优于平片（Ｐ〈０．０１）；显示肿瘤病灶横向范围，ＭＲＩ和ＣＴ无显著性差异。ＭＲＩ可清晰显示肿瘤病灶的边缘，断层标本取材证实距病灶边缘０．５ｃｍ内“正常”组织无瘤细胞浸润。结论：ＭＲＩ显示     

小儿腹膜后成神经细胞瘤影像学与病理的对照研究

目的 探讨ＣＴ、ＭＲＩ对小儿腹膜后成神经细胞瘤的诊断价值和限度。方法 对３２例中２０例术前同时行ＭＲＩ、ＣＴ检查者与术中所见对照,并对其中１９例术后离体肿瘤的ＭＲＩ、ＣＴ影像与病理大切片对照。结果 ＭＲＩ表现一般为Ｔ１Ｗ１中低信号,Ｔ２Ｗ１明显高信号,且可见低信号网格及肿瘤对血管的包绕。组织学基础：原始成神经细胞核大密集,无间质;瘤巢周围有神经纤维。ＣＴ表现肿瘤为不均匀低密度,可见钙化。术前判断肿     

儿童后颅凹肿瘤的CT, MRI诊断

目的：分析儿童后颅凹常见肿瘤的ＣＴ和ＭＲＩ影像学表现,提高诊断该病的准确性。材料和方法：收集儿童后颅凹常见肿瘤４０例,其中髓母细胞瘤１８例,星形细胞瘤１３例,室管膜瘤９例。行ＣＴ和ＭＲＩ检查。ＣＴ平扫４０例,增强扫描３２例;ＭＲＩ平扫２８例,增强扫描１６例。将其结果与手术病理对照。结果：４０例儿童后颅凹常见肿瘤ＣＴ显示率为９７５％,ＭＲＩ显示率为１００％。术前ＣＴ定性误诊１１例,准确率为７２５％。术前ＭＲＩ定性误诊４例,准确率为８５７％。ＣＴ和ＭＲＩ联合检查,能对后颅凹多数常见肿瘤作出定位及定性诊断。ＭＲＩ能多方位成像,去除后颅凹颅骨伪影的干扰,对该病的定位定性诊断明显优于ＣＴ。结论：ＣＴ和ＭＲＩ检查相结合,能提高诊断儿童后颅凹常见肿瘤的准确率,为临床提供更准确的诊疗信息。     

囊性肾癌的CT诊断

目的：探讨ＣＴ及ＭＲＩ诊断囊性肾癌的价值。材料与方法：囊性肾癌９例的ＣＴ及ＭＲＩ特征性表现分析与手术病理对照。结果;肿瘤位于右肾６例,左肾３例,呈椭圆形及不规则形。ＣＴ呈囊性低密度区,ＭＲＩ的Ｔ１ＷＩ呈低信号,Ｔ２ＷＩ呈高信号区。ＣＴ及ＭＲＩ的特征性表现：（１）肿瘤囊壁厚薄不均,可伴有囊内壁结节;（２）单囊腔多于多囊分隔;（３）肿瘤由肾实质向外生长,肿瘤与肾脏构成“８”字形;（４）肿瘤压缩肾向腹腔     

囊性肾癌的CT诊断(附9例分析)

目的：探讨ＣＴ及ＭＲＩ诊断囊性肾癌的价值。材料与方法：囊性肾癌９例的ＣＴ及ＭＲＩ特征性表现分析与手术病理对照。结果：肿瘤位于右肾６例,左肾３例,呈椭圆形及不规则形。ＣＴ呈囊性低密度区,ＭＲＩ的Ｔ１ＷＩ呈低信号,Ｔ２ＷＩ呈高信号区。ＣＴ及ＭＲＩ的特征性表现：（１）肿瘤囊壁厚薄不均,可伴有囊内壁结节;（２）单囊腔多于多囊分隔;（３）肿瘤由肾实质向外生长,肿瘤与肾脏构成“８”字形;（４）肿瘤压迫肾脏向腹腔移位及肾脏代偿性增大。结论：本研究总结的ＣＴ及ＭＲＩ特征性表现,为囊性肾癌的诊断与鉴别提供了依据。     

颈动脉间隙占位性病变的影像学分析(附19例报告)

分析颈动脉间隙病变的影像学表现,以探讨该区域病变的鉴别诊断及影像学检查方法的选择。方法１９例中,副神经节瘤５例,神经鞘瘤２例,淋巴结转移癌５例,淋巴瘤２例,感染性病变２例,Ｋｉｍｕｒａ病１例,颈内静脉血栓２例。ＣＴ检查１５例,ＭＲＩ检查４例。     

颈静脉孔区肿瘤的CT和MRI诊断

目的：探讨CT和MRI对颈静脉孔区肿瘤的诊断及鉴别诊断。方法：回顾性分析了经手术病理证实的34例颈静脉孔区肿瘤的CT和MR影像资料,其中包括颈静脉球瘤12例,神经鞘瘤10例,转移瘤3例,脑膜瘤2例,神经纤维瘤、脊索瘤、软骨瘤、软骨肉瘤、纤维脂肪瘤、纤维血管瘤和先天性囊肿各1例。CT检查21例,其中15例作增强扫描。MRI检查31例,其中24例加作MR增强扫描。结果：肿瘤内纡曲流空的血管即“椒-盐”征是颈静脉球瘤的特征性MRI表现。神经鞘瘤易发生囊变,注射对比剂后肿瘤中度强化。转移瘤骨质破坏不规则。脑膜瘤增强扫描可见脑膜“尾巴”征。软骨瘤和软骨肉瘤可见明显钙化。结论：CT与MRI相结合能更全面地为临床提供诊断、鉴别诊断及治疗所需要的信息,为治疗方法的选择提供可靠的依据。     

听神经瘤CT、MRI诊断比较

目的：比较听神经瘤的CT、MRI诊断价值。方法：回顾性分析26例经手术和病理证实的听神经瘤的CT、MRI表现。结果：听神经瘤的MRI表现为桥小脑角区圆形或类圆形肿块,于T1WI呈低信号或等信号,T2WI呈高信号或混杂信号;增强扫描显示病灶实质部分及增粗的听神经明显强化,呈“苹果柄”样改变。CT表现为桥小脑角部低密度或等密度病灶,薄扫可见同侧内听道口扩大。结论：CT能直观地显示内听道口的扩大,但常规扫描易漏诊。／MRI多层面成像及无骨伪影的优点,对显示听神经瘤瘤体及病侧听神经增粗很有价值,增强后的“苹果柄”样改变是听神经瘤特征性的表现。     

肝脏血管平滑肌脂肪瘤的CT及MRI征象分析

目的 分析13例肝脏血管平滑肌脂肪瘤（AML）的CT及MRI表现,进一步提高诊断准确性。方法 所有病例均经手术病理证实。12例经CT检查,其中6例做过MRI检查,仅1例只做MRI检查。平扫后行增强动脉期和门脉期扫描,5例做了延迟期扫描。MRI检查行SE T1WI、快速自旋回波（FSE）T2WI和快速多层面干扰梯度回波（FMPSPGR）序列横断面动态多期增强扫描。结果 CT平扫11个病灶为低密度,1个为略高密度。动脉期所有病灶均有强化表现,8个病灶见到中心血管影。门脉期8个病灶有持续强化,有6个病灶见到中心血管影。MR T1WI上5个病灶为混杂信号,T2WI上所有病灶均为高信号,但信号强度各不相同。MR增强动脉期6个病灶有强化,1个病灶强化不明显。门脉期4个病灶有持续强化,3个为低信号。MR增强扫描中也有4个病灶显示中心血管影。结论 CT和MRI检查均可显示AML的特征,特别是病灶中脂肪成分和血管影高度提示AML的诊断。MR SE序列加脂肪抑制显示脂肪成分比CT更加敏感。CT和MR动态增强多期扫描可充分反映AML的强化特征,有助于提高AML的诊断准确性。     

Discrimination and anatomical mapping of PET-positive lesions: comparison of CT attenuation-corrected PET images with coregistered MR and CT images in the abdomen

Purpose

PET/MR has the potential to become a powerful tool in clinical oncological imaging. The purpose of this prospective study was to evaluate the performance of a single T1-weighted (T1w) fat-suppressed unenhanced MR pulse sequence of the abdomen in comparison with unenhanced low-dose CT images to characterize PET-positive lesions.

Methods

A total of 100 oncological patients underwent sequential whole-body ¹⁸F-FDG PET with CT-based attenuation correction (AC), 40?mAs low-dose CT and two-point Dixon-based T1w 3D MRI of the abdomen in a trimodality PET/CT-MR system. PET-positive lesions were assessed by CT and MRI with regard to their anatomical location, conspicuity and additional relevant information for characterization.

Results

From among 66 patients with at least one PET-positive lesion, 147 lesions were evaluated. No significant difference between MRI and CT was found regarding anatomical lesion localization. The MR pulse sequence used performed significantly better than CT regarding conspicuity of liver lesions (p?<?0.001, Wilcoxon signed ranks test), whereas no difference was noted for extrahepatic lesions. For overall lesion characterization, MRI was considered superior to CT in 40?% of lesions, equal to CT in 49?%, and inferior to CT in 11?%.

Conclusion

Fast Dixon-based T1w MRI outperformed low-dose CT in terms of conspicuity and characterization of PET-positive liver lesions and performed similarly in extrahepatic tumour manifestations. Hence, under the assumption that the technical issue of MR AC for whole-body PET examinations is solved, in abdominal PET/MR imaging the replacement of low-dose CT by a single Dixon-based MR pulse sequence for anatomical lesion correlation appears to be valid and robust.     

CT和MRI对颅内表皮样囊肿诊断价值的评价

目的：评估CT和MRI对颅内表皮样囊肿的诊断价值，分析误诊原因，提高诊断水平。方法：44例经手术和病理证实的颅内表皮样囊肿，术前全部行常规MRI检查，其中19例行Gd-DTPA增强MRI检查；17例作CT平扫，其中12例作静脉注射增强CT检查。结果：颅内表皮样囊肿多位于桥小脑角池，本组病例中占34．9％(15／4例)；肿瘤多呈不规则形态，占70．45％(31／44例)；CT平扫多呈均匀低密度，占70．59％(12/17例)，造影后多无强化，占91．71％(11／12例)；MRT1加权像上多呈均匀低信号，但略高于脑脊液，T2加权像上多呈均匀高信号，占61．36％(27／44例)，Gd-DTPA增强后多无强化，占84．21％(16／19例)。肿瘤周围的脑组织均无水肿，占100％，肿瘤较大时可以挤压、推移周围脑组织或脑室结构，引起比较明显的占位效应，占70．45％(31／44例)；肿瘤较大时，很少引起阻塞性脑积水。结论：颅内表皮样囊肿在CT和MRI像上有特征性表现，MRI无论在定位和定性诊断上优于CT，Gd-DTPA的应用有助于颅内囊性占位的诊断与鉴别诊断。     

Focal liver lesions: comparison of dual-phase CT and multisequence multiplanar MR imaging including dynamic gadolinium enhancement

The purpose of this study was to compare dual-phase spiral computed tomography (CT) and magnetic resonance imaging (MRI) using dynamic gadolinium enhancement for liver lesion detection and characterization. Twenty-two consecutive patients underwent dual-phase spiral CT and MRI for the evaluation of focal liver disease within a 1-month period. Spiral CT and MR images were interpreted prospectively, in a blinded fashion by separate, individual, experienced investigators, to determine lesion detection and characterization. Liver lesions were confirmed by surgery and pathology in 6 patients, and by clinical and imaging follow-up in the other 16 patients. Pathological correlation of a primary extrahepatic malignancy was available in 5 of the 16 patients who had metastatic liver disease. Spiral CT and MRI detected 53 and 63 lesions, and characterized 39 and 62 true positive lesions, respectively. A kappa statistic test was applied to assess agreement between MR and CT results. MR versus CT for lesion detection resulted in a kappa statistic of 0.54 (95% confidence interval), indicating moderate agreement, and 0.32 (95% confidence interval) for lesion characterization, indicating only slight agreement. More lesions were detected on MR images than CT images in 6 (27%) patients, with lesions detected only on MR images in 4 (18%) patients. More lesions were characterized on MR images in 9 (41%) patients. In 9 patients with a discrepancy between MR and CT findings, the MR images added information considered significant to patient management in all 9 cases. MRI was moderately superior to dual-phase spiral CT for lesion detection, and was markedly superior for lesion characterization, with these differences having clinical significance.     

Iodine-123-metaiodobenzylguanidine scintigraphy in patients with chemodectomas of the head and neck region

While studying the uptake of iodine-123-metaiodobenzylguanidine ([123I]MIBG) in chemodectomas, we coincidentally detected catecholamine secreting tumors in 5 out of 14 patients. In three of these cases, a norepinephrine secreting abdominal paraganglioma was subsequently removed. One patient had a norepinephrine secreting chemodectoma and one had a dopamine secreting chemodectoma. Prior to [123I]MIBG imaging and urinary catecholamine measurements, endocrine activity was suspected in only one of these five patients. Apart from these five cases, two other patients showed elevated catecholamine secretion and abnormal abdominal [123I]MIBG concentrations. However, these two patients were not surgically explored, because of normal computed tomography (CT) and magnetic resonance (MRI) studies. We suspect that catecholamine-secreting tumors are more common in patients with chemodectomas than is assumed in the literature, and we therefore recommend urinary catecholamine screening for all patients with chemodectomas. In case of elevated catecholamine secretion, MIBG scintigraphy is indicated.     

Indeterminate Findings on Oncologic PET/CT: What Difference Does PET/MRI Make?

Background

Positron emission tomography/computed tomography (PET/CT) with 2-deoxy-2-[¹⁸F]fluoro-D-glucose (FDG) has become the standard of care for the initial staging and subsequent treatment response assessment of many different malignancies. Despite this success, PET/CT is often supplemented by MRI to improve assessment of local tumor invasion and to facilitate detection of lesions in organs with high background FDG uptake. Consequently, PET/MRI has the potential to expand the clinical value of PET examinations by increasing reader certainty and reducing the need for subsequent imaging. This study evaluates the ability of FDG-PET/MRI to clarify findings initially deemed indeterminate on clinical FDG-PET/CT studies.

Methods

A total of 190 oncology patients underwent whole-body PET/CT, immediately followed by PET/MRI utilizing the same FDG administration. Each PET/CT was interpreted by our institution's nuclear medicine service as a standard-of-care clinical examination. Review of these PET/CT reports identified 31 patients (16 %) with indeterminate findings. Two readers evaluated all 31 PET/CT studies, followed by the corresponding PET/MRI studies. A consensus was reached for each case, and changes in interpretation directly resulting from PET/MRI review were recorded. Interpretations were then correlated with follow-up imaging, pathology results, and other diagnostic studies.

Results

In 18 of 31 cases with indeterminate findings on PET/CT, PET/MRI resulted in a more definitive interpretation by facilitating the differentiation of infection/inflammation from malignancy (15/18), the accurate localization of FDG-avid lesions (2/18), and the characterization of incidental non-FDG-avid solid organ lesions (1/18). Explanations for improved reader certainty with PET/MRI included the superior soft tissue contrast of MRI and the ability to assess cellular density with diffusion-weighted imaging. The majority (12/18) of such cases had an appropriate standard of reference; in all 12 cases, the definitive PET/MRI interpretation proved correct. These 12 patients underwent six additional diagnostic studies to clarify the initial indeterminate PET/CT findings. In the remaining 13 of 31 cases with indeterminate findings on both PET/CT and PET/MRI, common reasons for uncertainty included the inability to distinguish reactive from malignant lymphadenopathy (4/13) and local recurrence from treatment effect (2/13).

Conclusions

Indeterminate PET/CT findings can result in equivocal reads and additional diagnostic studies. PET/MRI may reduce the rate of indeterminate findings by facilitating better tumor staging, FDG activity localization, and lesion characterization. In our study, PET/MRI resulted in more definitive imaging interpretations with high accuracy. PET/MRI also showed potential in reducing the number of additional diagnostic studies prompted by PET/CT findings. Our results suggest that whole-body PET/MRI provides certain diagnostic advantages over PET/CT, promotes more definitive imaging interpretations, and may improve the overall clinical utility of PET.

     

肝脏局灶结节性增生的CT、MRI诊断

目的:评估CT、MRI对肝脏局灶结节性增生(focal nodular hyperplasia,FNH)的诊断价值.材料和方法:回顾性分析9例FNH(6例经病理证实,3例经磁共振特异性对比剂Resovist证实)的CT、MRI表现和术前或穿刺前诊断.结果:8例为单发病灶、1例为3个病灶.10个病灶呈稍低密度,其中7个T1WI为稍低信号、T2WI稍高信号,3个病灶T1WI和T2WI为稍高信号;1个病灶为等密度和等信号;CT动脉期明显增强、门静脉期轻度增强或无增强;MRI的增强方式与CT相似,但10个病灶存在明显的延迟增强.7个病灶检出瘢痕,T1WI呈低信号、T2WI高信号,动脉期和门静脉期无增强、延迟期轻至中度增强.8例单发病灶均正确诊断为FNH.结论:CT和MRI能显示FNH的特征性改变并提高诊断的准确性.