椎管内神经瘤的增强磁共振成像研究

目的：评估增强后磁共振成像诊断椎管内神经瘤的特异性。材料和方法：对经外科手术的２０例椎管内神经瘤患者，回顾性比较分析病理和ＭＲＩ（包括Ｔ１加权成像、Ｔ２加权成像和静脉注射Ｇｄ－ＤＴＰＡ后Ｔ１加权成像）。结果：在Ｔ１加权像，与脊髓相比，呈均质低信号９例，不均质低信号１０例，不均质高信号１例；在Ｔ２加权像，２０例均示明显高信号（均质１３例，不均质７例）；静脉注射Ｇｄ－ＤＴＰＡ后Ｔ１加权成像，２０例均示明显强化，据其强化形态不同分为①均质强化８例；②明显不均质强化５例，病理上存在坏死囊变和陈旧性出血；③“煤渣状”不均质强化７例，病理上可能由不同量的ＡｎｔｏｎｉＡ和ＡｎｔｏｎｉＢ组织交互存在所造成或部分代表显微镜下见的微囊改变。结论：Ｔ１加权像呈低信号，Ｔ２加权呈明显的高信号，注射造影剂后出现明显的不均质强化和“煤渣状”不均质强化，是椎管内神经瘤的特征性ＭＲＩ征象。     

脑静脉血管瘤的MRI及MRA

目的：探讨颅内静脉血管瘤的ＭＲＩ和ＭＲＡ影像学表现及诊断和鉴别诊断。材料和方法：应用ＳｉｅｍｅｎｓＭｅｇｎｅｔｉｏｎＶｉｓｉｏｎ１．５Ｔ超导系统对诊断静脉血管瘤（ＶＡ）２０例进行分析。ＭＲＩ扫描用ＳＥＴ１和ＴｕｒｂｏＳＥＴ２加权序列。ＭＲＡ采用ｔｏｆ－ｔｉ３Ｄ－ｍｕｌｔｉ－ｓｌａｂ－ｔｒａ－ｔｕｎ序列。１６例作增强Ｔ１加权及ＭＲＡ检查。血管重建采用ＭＩＰ技术。有１１例曾行ＣＴ检查，１例行手术治疗。结果：所有病例均由ＭＲ检查作出首诊。Ｔ１加权１８例显示扩张引流静脉呈点条状低信号影，有２例未显示，经增强后显示，并有部分髓静脉显示。Ｔ２加权引流静脉多呈高信号，个别呈低信号。较大的ＶＡ亦可显示髓质静脉。ＭＲＡ１５例显示异常血管，典型的表现为脑实质内见为数不等的髓质静脉呈伞状汇入一根异常扩张的引流静脉，整个形态似“水母头”。１例ＭＲＡ未显示病灶。结论：ＭＲ是诊断ＶＡ最好的影像方法，ＭＲＡ有助于确诊本病。增强ＭＲＩ及ＭＲＡ可提高ＶＡ的检出率     

肝包虫病的磁共振诊断

本文对手术证实的８例肝包虫囊肿及５例肝泡状棘球蚴病的磁共振成像（ＭＲＩ）进行分析。包虫囊肿表现为圆形、卵圆形边缘光滑的影像，Ｔ１加权像呈低信号，Ｔ２加权像呈高信号。其特征性表现为病变有光滑均匀的低信号强度的囊壁及呈多房性的子囊，为ＭＲＩ诊断本病的重要依据。泡状棘球蚴呈巨块型，在Ｔ１和Ｔ２加权像上均呈低信号，境界不清，边缘不规整，中心液化坏死，呈溶岩状，偶见颗粒状钙化。还探讨了本病与非寄生虫性占位病     

胆管细胞型肝癌的CT,MRI及血管造影表现（附八例报告）

报告８例经手术及病理证实的胆管细胞型肝癌，主要观察其ＣＴ、ＭＲＩ及血管造影表现。８例中男６例，妇２例，年龄４２－６４岁，影像学检查包括、ＭＲＩ及血管造影，主要表现：（１）ＣＴ平扫为单发分叶状低密度块影，巨块型者密度不均；注射造影剂后４例呈边缘性增强（４／６）；１例伴有肝硬化、脾大。（２）ＭＲＩＴ１加权像上病变呈低信号，Ｔ２加权像上信号较高，５例可见瘢痕结构（５／７）；注射造影剂后早期，５例呈中等度     

脑血管畸形的MRI及MRA诊断

目的：研究脑动静脉畸形与海绵状血管瘤的ＭＲＩ及ＭＲＡ特征，评价不同的成像方法对脑血管畸形的诊断价值。材料与方法：对２１例脑动静脉畸形及６例海绵状血管瘤分别作了常规ＭＲ成像及ＭＲ血管成像，ＭＲＩ采用ＳＥＴ１和Ｔｕｒｂｏ ＳＥ Ｔ２加权序列，ＭＲＡ采用２Ｄ－ＦＬＡＳＨ及３Ｄ－ＦＩＳＰ序列，６例海绵状血管瘤ＭＲＡ仅使用２Ｄ－ＦＬＡＳＨ序列。所有成像以环形激化头线圈在１．０Ｔ ＭＲ仪上完成。结果：Ｔ１及Ｔ     

脑静脉窦闭塞的MR表现及与颅内压关系初探

目的：分析脑静脉窦闭塞的ＭＲ表现及其病理生理学改变，区分脑静脉窦闭塞与脑动脉缺血ＭＲ表现的不同点。材料与方法：回顾性总结３０例脑静脉窦闭塞ＭＲ平扫和增强扫描资料，其中男１２例，女１８例，年龄６～６９岁。观察有无占位效应，Ｔ２加权像异常信号，脑室大小改变以及造影后异常强化等ＭＲ表现。结果：１００％（３０／３０）病例于Ｔ１加权像见脑肿胀，３７％（１１／３０）病例于Ｔ２加权像出现异常信号，１６％（５／３０）病例脑室扩大，６％（２／３０）病例脑出血或脑水肿形成，８０％（２４／３０）病例出现静脉异常强化。结论：脑静脉窦闭塞ＭＲ表现与动脉性闭塞ＭＲ表现明显不同，它具有特殊的病理生理学变化，其发病机理与颅内压变化有关。仔细观察Ｔ１加权像对诊断静脉窦闭塞具有重要意义。     

实验性癫癎大鼠脑MRI与病理学对照研究

目的：观察１．５Ｔ ＭＲＩ检出大鼠痫性脑损伤的能力。材料和方法：Ｗｉｓｔａｒ大鼠３０只,毛果云香碱３５０ｍｇ／ｋｇ腹腔注射,诱发反复强真－痉挛全面大发作持续状态,ＨＦ染色,光镜下观察癫痫持续不同时间脑组织损害程度,并与１．５Ｔ ＭＲ成像对比（ＭＲＩ参数：ＳＥ序列Ｔ１加权像：重复时间＝５００ｍｓ,回波时间＝１５ｍｓ;ＦＳＥ序列Ｔ２加权像：重复时间＝４００ｍｓ;用表面线圈,层厚２．２ｍｍ,无间隔）。结果：癫痫持续时间与脑损伤呈相关性改变。癫痫持续３ｄ后,可见颞叶、海马区严重神经元脱失、胶质增生和脑水肿,ＭＲ扫描除在１只发作持续１８ｈ的大鼠左颞区检出长Ｔ１、长Ｔ２异常信号外（光镜提示为在灶）,未发现其余动物脑的结构异常和信号变化。结论：随着动物大发作持续时间延长,痫性脑损害加重,大鼠癫痫持续３ｈ以上,有明显的海马神经     

MRI诊断肝脏占位性少见病的探讨（附四例报告）

报道４例肝脏占位性少见病ＭＲＩ表现，肝结核瘤Ｔ１加权像呈低信号，Ｔ２加权像与肝脏等信号和不均高信号。局限性肝结节增生Ｔ１加权像与肝脏等信号，Ｔ２加权像呈等信号或高信号。肝巨大纤维瘢块Ｔ１、Ｔ２加权像均呈低信号。肝脏炎性假瘤在Ｔ１加权像呈中低信号，Ｔ２加权像呈中高信号。根据ＭＲＩ表现结合临床资料有可能对部分病变做出诊断。     

高场磁共振仪评估新生儿和婴儿的正常脑髓鞘

目的：应用高场ＭＲ仪研究正常小儿不同月龄段的脑髓鞘与对应ＭＲＩ信号特征。方法：５８例正常小儿在１．５Ｔ ＭＲ仪内行头部扫描。采用自旋回波（ＳＥ０和快速自旋回波（ＴＳＥ）序列,获取Ｔ１和Ｔ２架驻像,结果：（１）髓鞘形成中的ＭＲＩ信号变化,相对于灰质信号,未的髓鞘呈短Ｔ１和长Ｔ２,在Ｔ１ＷＩ上呈高信号与灰质易区别,在Ｔ２ＷＩ上与灰质信号相近;的髓鞘呈短Ｔ１和短Ｔ２;在Ｔ２ＷＩ上呈低信号,与灰质易区别;     

脊髓表皮样囊肿的MR诊断

目的分析脊髓表皮样囊肿的ＭＲ表现，以提高对该病的神经放射学认识。材料与方法搜集１８例经手术病理证实的脊髓表皮样囊肿。重点分析了肿瘤的好发年龄、部位、ＭＲ信号特点和肿瘤的增强情况。结果在本组病例中，病人年龄最小４岁，最大４２岁，平均年龄２４．５岁。本组病例全部发生于圆锥附近，边缘清楚。大部分肿瘤长度小于２个椎体长度（１６／１８），２例肿瘤长度大于３个锥体长度，Ｔ１加权像肿瘤呈均匀的等（６／１８）、高（２／１８）和混杂信号（１０／１８）。Ｔ２加权像呈高信号，边缘可呈等Ｔ２信号。在７例行增强扫描的病人中，有４例肿瘤周围可见轻微强化，３例无强化。９例肿瘤内可见脂肪信号。本组中未见其他有关先天性畸形。结论脊髓内表皮样囊肿的ＭＲ表现较具特征性。该病多见于青年患者，好发于圆锥附近，多呈长Ｔ１、Ｔ２信号。增强扫描无或仅有周围轻微强化。     

MR imaging features of pure mucinous carcinoma of the breast

OBJECTIVE: To characterize MR imaging features of pure mucinous carcinoma of the breast. MATERIALS AND METHODS: MR images obtained from 16 women (age range, 29-81; mean age, 57 years) with pure mucinous carcinoma of the breast determined at surgery were reviewed. The MR findings used were shape, margin, internal mass enhancement, kinetic curve pattern on dynamic study, signal intensity on short time inversion recovery (STIR) T2-weighted images, and non-mass-like enhancement around the main tumor. Non-mass-like enhancement was compared with the presence of extensive intraductal component (EIC) on histopathological findings. RESULTS: Eleven tumors (69%) had lobular contour, and nine tumors (56%) had smooth margin. Eight tumors (50%) showed rim enhancement and six tumors (38%) showed heterogeneous enhancement. Fourteen tumors (88%) showed a persistent enhancing pattern on kinetic curve. Fifteen tumors exhibited homogenous strongly high signal intensity on STIR T2-weighted images. In six cases with EIC, five cases had non-mass-like enhancement around the main mass. CONCLUSIONS: MR findings such as lobular shape, rim or heterogeneous enhancement, persistent pattern on kinetic curve, and homogeneous strongly high signal intensity on STIR T2-weighted images may be useful in diagnosing pure mucinous carcinoma. Moreover, linear-ductal enhancement around main mass may indicate presence of EIC.     

Oligodendroglioma metastatic to bone marrow

We report on a patient with oligodendroglioma metastatic to bone, presenting with pancytopenia and fever 10 years after initial tumor resection. Our review of the literature showed a total of 30 reported extraneural metastases, with only 19 of these being similar cases of bone metastases. These bony lesions have increased signal intensity in T2-weighted and low signal intensity on T1-weighted images, with intense homogeneous enhancement. However, on MR imaging, we were unable to find necrosis or compression deformity of the vertebrae, despite extensive metastatic disease.     

Non-Hodgkin lymphomas of the ovaries: MR findings

PURPOSE: The goal of this work was to describe MR findings (morphology, structure, signal intensity) of ovarian non-Hodgkin lymphoma (NHL). METHOD: We reviewed the MR images of five female patients aged 13-70 years (mean 46 years) with histologically proven NHL of the ovaries. We evaluated morphological and signal intensity findings of the lesions. MR features were correlated with pathologic parameters. RESULTS: All the patients were affected by B-cell NHL; one patient showed a primary involvement of the ovaries; in one patient, ovarian disease was diagnosed 30 months after surgical resection of a primary uterine lymphoma; the remaining three had a systemic lymphoma. In three cases, the ovarian involvement was bilateral. The mean size of the lesions was 7.9 cm. All the lesions showed homogeneous low signal intensity on T1-weighted images and intermediate to high intensity on T2-weighted images. The postgadolinium images showed mild to moderate heterogeneous enhancement. The peripheral enhancement was better demonstrated in fat-suppressed images. CONCLUSION: The diagnosis of primary ovarian lymphoma should be considered in the presence of large bilateral solid ovarian masses with homogeneous appearance (low signal on T1 and mildly high on T2) without infiltrative pattern of growth or regressive changes (necrosis, hemorrhage, calcifications) and with little contrast enhancement.     

MR imaging of tuberculous arthritis: Clinical and experimental studies

Signal-intensity characteristics of magnetic resonance (MR) images were assessed in five patients and in 10 rabbits with tuberculous arthritis. MR imaging findings were compared with histologic findings in the animal study. In both of clinical and experimental cases, tuberculous lesions showed both intermediate and high signal intensity on T2-weighted images, while they showed heterogeneously intermediate signal intensity on T1-weighted images. As T2-weighted images were compared with pathologic specimens, intermediate signal intensity corresponded to caseous necrosis, whereas high signal intensity related to granulomas or effusion. Postcontrast T1-weighted images showed enhancement at the peripheries rather than the centers of tuberculous lesions. These results indicate that tuberculous arthritis should be included in the differential diagnosis when intra-articular lesions with low or intermediate signal intensity are found on T2-weighted images.     

Tophaceous gout of the spine: MR imaging features

AIM: To define the magnetic resonance (MR) imaging features of tophaceous gout of the spine. MATERIALS AND METHODS: We present the MR imaging examinations of 4 patients with spinal tophaceous gout. Spin-echo T1-weighted and fast spin-echo T2-weighted images were obtained for all patients, and 2 patients had gadolinium-enhanced MR imaging studies. Corresponding computed tomography (CT) was performed in one patient. All images were evaluated for the characteristics of the gouty tophi. RESULTS: The gouty tophi were located at the lower thoracic (n=1) and lumbar (n=3) levels. All tophi yielded homogeneous intermediate to low signal on T1-weighted images and variable signal intensity on T2-weighted images, comprising small foci of very low signal intensity on all sequences. Gadolinium-enhanced MR imaging studies revealed homogeneous enhancement or heterogeneous peripheral enhancement. Diffuse stippled calcifications were found in the tophi on CT images. Periarticular tophi with juxtaarticular bony erosions around facet joints occurred in 3 patients. CONCLUSION: Spinal tophaceous gout should be considered in the differential diagnosis when periarticular deposits contain very low signal foci on all MR imaging sequences.     

Magnetic resonance imaging spectrum of spinal meningioma

PurposeTo evaluate magnetic resonance (MR) imaging findings of spinal meningioma and to determine the radiological subtypes based on the MR imaging findings and their respective clinical features.Material and methodsData for 105 patients with surgically treated and histopathologically diagnosed spinal meningiomas at our hospital between May 1, 2003 and May 1, 2017 were evaluated in this study. Two radiologists reviewed the characteristics of spinal meningiomas on MR images and categorized the spinal meningiomas into subtypes based on MR imaging findings.ResultsMost spinal meningiomas showed higher signal intensity than that of the spinal cord but lower than that of the subcutaneous fat on T2-weighted images (WI). 56 cases (54%) showed adjacent spinal cord signal changes. Meningiomas could be categorized according to MR imaging findings into type A: dural-based tumors with a homogeneous signal intensity and intense contrast enhancement (81 cases, 77%); type B: round or oval-shaped tumors with an internal hypointense portion on T2-weighted images (18 cases, 17%); type C: en plaque tumors (three cases, 3%); and type D: tumors with unusual findings and a heterogeneous appearance (three cases, 3%). All type C patients showed spinal cord signal changes.ConclusionsSpinal meningioma showed slightly high signal intensity rather than high signal intensity on T2-weighted images. Spinal cord signal changes were present in more than half of the cases. Clinical differences were observed among the different MR imaging types.     

Subcortical low intensity in early cortical ischemia.

PURPOSETo describe subcortical low intensity on T2- and proton density-weighted MR images in early cortical ischemia and to discuss a cause of these findings.METHODSNine patients with early cortical ischemia were studied with proton density- and T2-weighted images, and T1-weighted images at 1.5 T. Gadolinium enhancement was added in six cases.RESULTSIn all cases there was high to intermediate intensity in the cortex and low intensity in the subcortical white matter (subcortex) on the proton density- and T2-weighted images. No significant signal abnormalities were shown on T1-weighted images in the subcortex; gyriform enhancement was seen in the affected cortex in all of the six patients studied with gadolinium. Of the four patients with follow-up MRs, the subcortical low intensity changed to high intensity in two and remained low in two patients in the chronic stage. Neither hemorrhage nor calcification was seen on CT.CONCLUSIONIron accumulation in the subcortex caused by disruption of the axonal transportation and continuous production of free radicals caused by the hypoxic-ischemic state most likely reduces the signal intensity of the subcortex on the proton density- and T2-weighted images. The subcortical low intensity on the proton density- and T2-weighted images is an important diagnostic sign of early cortical ischemia.     

Contrast-enhanced fluid-attenuated inversion recovery imaging for leptomeningeal disease in children

BACKGROUND AND PURPOSE: To develop an MR imaging method that improves detection of leptomeningeal disease when compared with the current reference standard, contrast-enhanced T1-weighted imaging. METHODS: We investigated the cases of 10 children who were at high risk of intracranial leptomeningeal disease (Sturge-Weber syndrome and medulloblastoma). The cases of Sturge-Weber syndrome were investigated by using one MR imaging examination, and the cases of medulloblastoma were investigated by using four MR imaging examinations performed over 18 months. In all cases, contrast-enhanced fluid-attenuated inversion recovery (FLAIR) images were acquired in addition to the routine sequences. The parameters of the FLAIR sequence were chosen to maximize the T1 component of the signal intensity, to maximize detection of leptomeningeal enhancement. We made subjective and objective assessments of the presence and extent of leptomeningeal disease as shown on contrast-enhanced T1-weighted images and contrast-enhanced FLAIR images. RESULTS: In three of the four cases of Sturge-Weber syndrome, the T1 and FLAIR sequences showed comparable extent of leptomeningeal enhancement. For one child, FLAIR images showed unexpected bilateral disease and more extensive leptomeningeal enhancement on the clinically suspected side. In four of six cases of medulloblastoma, no leptomeningeal enhancement was shown on any examinations during the 18-month period. In two cases, FLAIR images showed more extensive leptomeningeal enhancement when compared with T1-weighted images. CONCLUSION: Contrast-enhanced FLAIR imaging seems to improve detection of leptomeningeal disease when compared with routine contrast-enhanced T1-weighted imaging. This seems to be partly because of suppression of signal intensity from normal vascular structures on the surface of the brain by FLAIR, which allows easier visualization of abnormal leptomeninges. We think that these findings can be extrapolated to the investigation of leptomeningeal disease of all causes and at all ages.     

Non-heme mechanisms for T1 shortening: pathologic, CT, and MR elucidation.

PURPOSE: To further elucidate the nonparamagnetic effects of T1-relaxation mechanisms in MR imaging. PATIENTS AND METHODS: In 12 patients with lesions having hyperintense signal on T1-weighted spin-echo MR, findings were correlated with autopsy/surgical biopsy in seven cases and/or noncontrast CT scans in 10 cases. RESULTS: Eight of the 10 CT scans demonstrated hyperattenuation in the lesions, indicating mineralization, which correlated with the areas of hyperintense signal on MR. Histologic characterization of the mineralization was accomplished in three cases using four stains; hematoxylineosin, alizarin red S, von Kassa stains for calcium and Perls' iron. The areas of mineralization were homogeneously strongly positive with the calcium stains and only focally weakly positive with the Perls' iron stain. The mineralization was further characterized in all three cases as containing calcium and phosphorus using energy-dispersive x-ray analysis. Four of the 12 cases had either no correlating CT scans (two cases) or the CT showed no hyperattenuating properties to the lesions (two cases). In all four of these cases, microscopic examination showed that the gyriform configuration of the cortical hyperintense signal on T1-weighted images correlated with linear zones of nonhemorrhagic laminar necrosis (cerebral infarction). No mineralization, except for an occasional ferruginated neuron, could be demonstrated with the four histologic stains. Specimen MR imaging of formalin-fixed brain sections in one case demonstrated in vitro the gyriform hyperintense signal seen in vivo. CONCLUSION: Our studies describe and pathologically characterize two associations with T1 shortening in neuroimaging unrelated to the presence of heme: 1) calcification and 2) laminar necrosis in cerebral infarction.     

Amyloid arthropathy of the hip joint: MR demonstration of presumed amyloid lesions in 152 patients with long-term hemodialysis

The aim of this study was to determine the spectrum of MR findings of presumed amyloid arthropathy of the hip joints in patients on long-term hemodialysis. We prospectively performed T1- and T2-weighted spin-echo imaging on 152 consecutive patients on hemodialysis. The duration of hemodialysis ranged from 5 months to 24 years, 2 months (mean: 8 years, 8 months). The frequency, location, and signal intensity of bone lesions were assessed. In 12 cases with contrast-enhanced MR examination, enhancement pattern of bone lesions, synovial lesions, and intra-articular lesions were characterized. Bone lesions presumed to be amyloid deposits were identified in 60 patients (39 %). Magnetic resonance imaging revealed that amyloid lesions were more extensive than anticipated by plain radiographs. All bone lesions showed decreased signal intensity on T1-weighted images. On T2-weighted images, bone lesions showed increased signal intensity in 32 patients (54 %), decreased signal intensity in 11 patients (18 %), and both increased and decreased signal intensity in 17 patients (28 %). Following intravenous injection of gadolinium-based contrast, all bone lesions showed moderate enhancement. Synovial thickening could not be identified on T1- and T2-weighted images. However, contrast-enhanced images showed thickened synovial membrane, which could be differentiated from joint fluid. Intra-articular nodules showed decreased or intermediate signal intensity on T1-weighted images and decreased signal intensity on T2-weighted images; the intra-articular nodules were contiguous with subchondral bone lesions. Magnetic resonance imaging is useful for evaluating the distribution and extent of amyloidosis of the hip joints in patients undergoing long-term hemodialysis. Received 5 August 1997; Revision received 22 October 1997; Accepted 11 February 1998