长骨骨干骨肉瘤X线、CT及MRI表现

目的 分析长骨骨干骨肉瘤X线、CT和MRI表现,探讨有关的临床特点和鉴别诊断.方法 28例长骨骨干骨肉瘤患者,均经手术与病理证实,其中病变位于股骨干18例、腓骨干4例、肱骨干4例、胫骨干2例.所有患者均行X线、CT和MR检查,对其影像学表现与手术病理结果进行对照,并由双盲法分析确认.结果 28例中,X线和CT显示广泛骨质破坏16例,骨膜反应22例.X线显示软组织肿块18例,肿瘤骨和瘤样钙化12例.CT平扫显示软组织肿块22例,增强扫描显示软组织肿块24例,肿瘤骨和瘤样钙化16例.MRI显示骨质破坏和骨膜反应10例,软组织肿块26例,其周围可见软组织水肿及骨髓水肿.骨膜反应在SE T1WI上呈等低信号,T2WI呈等信号.软组织肿块在T1WI为等信号,T2WI及STIR呈等高信号.软组织水肿及骨髓水肿在T2WI及STIR呈高信号.MRI增强检查显示病灶均呈不均匀强化,骨髓水肿和软组织肿块均见强化.结论 X线、CT和MRI从不同方面反映长骨骨干骨肉瘤的影像病理特点,其发病率低,骨破坏范围大,无病理性骨折.成骨型骨干骨肉瘤较易诊断,溶骨型应与Ewing瘤、恶性巨细胞瘤等鉴别.

Abstract：

Objective To explore the findings of diaphysial osteosarcoma in long bone on X-ray,CT and MRI, and discuss their clinical features and manifestations for differential diagnosis. Methods Twenty-eight cases with diaphysial osteosarcoma in long bone proved by surgery and pathology were reviewed retrospectively. Eighteen tumors were located in the femur, 4 in fibula, 4 in humerus and 2 in tibia. All of the patients were examined by X-ray, CT and MRI. The imaging manifestations on X-ray, CT and MRI were analyzed, and the relationship of the imaging features with the pathological types was also observed. The imaging signs were correlated with the pathologic findings with a double blind method. Results Of the 28 cases, there were 16 cases with large bone destruction, 22 cases with periosteal reaction on X-ray and CT. On X-ray, 18 cases showed soft tissue mass and 12 cases with neoplastic bone and tumor calcification.While on CT, 22 cases showed soft tissue mass on plain scan and 2 more cases displayed soft tissue mass after the injection of contrast mediun. Sixteen cases showed neoplastic bone and tumor calcification on CT.On MRI, there were 10 cases with bone destruction and periosteal reaction with iso- and hypo-intense on T1WI and iso- signals on T2WI. Twenty-six cases showed soft tissue edema and bone marrow on MRI. The soft mass were iso-signals on T1 WI and iso-hyperintense signals on T2 WI or STIR. The soft tissue edema was found hyperintense signals on T2WI or STIR. The lesions had heterogeneous enhancement especially in bone marrow with edema and adjcent soft tissue. Conclusion The X-ray, CT and MRI can reflect the pathological changes of diaphysial osteosarcoma in long bone from different aspects. Lower incidence, large bone destruction and no pathological fracture were the features of diaphysial osteosarcoma. The osteogenic type is diagnosed easily, but the osteolytic lesion should be differentiated from Ewing sarcoma, malignant giant cell tumor of bone and so on.     

Periosteal osteoblastoma of the distal femur

Osteoblastomas located on the surface of the cortical bone, so-called periosteal osteoblastomas, are extremely rare. We report on a case of periosteal osteoblastoma arising from the posterior surface of the right distal femur in a 17-year-old man. Roentgenographic, computed tomographic, magnetic resonance imaging, and histologic features of the case are presented. Periosteal osteoblastoma should be radiologically and histologically differentiated from myositis ossificans, avulsive cortical irregularity syndrome, osteoid osteoma, parosteal osteosarcoma, periosteal osteosarcoma, and high-grade surface osteosarcoma. Although periosteal osteoblastoma is rare, this tumor should be included in the differential diagnosis of surface-type bone tumors.     

Evolution of VX2 carcinoma in rabbit tibia: magnetic resonance imaging with pathologic correlation

OBJECTIVE: To evaluate the evolution of a metastatic bone tumor model with MRI-pathology correlation. MATERIALS AND METHODS: VX2 carcinoma was implanted into the tibiae of 20 rabbits. The rabbits were divided into four groups of five (Groups I-IV). MRI was repeated at 1-week interval up to the fourth week, including sagittal T1-weighted image (T1WI), T2-weighted image (T2WI), gadolinium-enhanced fat-suppressed T1WI (GdT1WI), and diffusion-weighted image (DWI). Each group was sacrificed after the imaging, then histological examination for the tibiae with an implanted tumor was performed and MRI-pathologic correlation was done. RESULTS: On MRI-pathology correlation, the corresponding findings were as follows; low SI on T1WI, T2WI-tumor cells, fibrosis (1 week); central low SI on T1WI, T2WI, GdT1WI -tumor cells with fibrosis and necrosis; peripheral high SI on T2WI, DWI, GdT1WI-edema, fibrosis (2 weeks); heterogeneous SI with central low SI on T2WI, DWI-tumor cell nests with extensive necrosis, fibrosis; high SI on T2WI along periosteum-periosteal reaction; high SI around low SI and in bone marrow on T2WI, DWI, GdT1WI-edema, fibrosis; low SI on T1WI in surrounding bone marrow-tumor extension (3-4 weeks). CONCLUSION: The evolution of VX2 carcinoma model was well depicted on MR imaging. Necrosis and extent of tumor were best depicted on enhanced, fat-suppressed T1-weighted images. Heterogeneity of the tumor, peripheral edema, and fibrosis were represented well on T2-weighted images. Diffusion-weighted imaging could have a role in depicting necrosis in the evaluation of bone tumor.     

The value of dynamic contrast-enhanced MRI in diagnosis of malignant lymphoma of the head and neck

In this study, we attempted to diagnose malignant lymphoma on the basis of magnetic resonance imagings (MRIs) and dynamic contrast-enhanced MRI (DCE-MRI). Eighteen lesions (in eight patients), all of which had been proven histopathologically, were detected on MRI. The eight patients included five patients with diffuse large B-cell lymphoma, one with B-cell low-grade MALT lymphoma, one with follicular lymphoma, and one with Hodgkin's lymphoma. Nine lesions were located in the submandibular region, three in the buccal region, two in the orbit region, two in the submental region, and one each in the palatal and tonsil regions. The diameter of the lesions ranged between 9 and 42.2 mm (average: 22.4 mm). The signal intensities (SIs) of the 18 lesions were examined on T1-weighted (T1WI), T2WI, and gadopentetate (Gd)-T1WI. One lesion in case 8 was excluded from DCE-MRI findings, i.e., the regions of interest could not be adequately set on DCE-MRIs. The contrast index (CI) curves of the remaining 17 lesions were prepared. All 18 lesions showed almost the same images on T1WI, T2WI, and Gd-T1WI, although they represented four types of lymphoma. The images showed homogeneous SI that was intermediate to slightly high SI on T1WI, slightly high SI on T2WI, and moderately enhanced on Gd-T1WI. Thus, the cases of malignant lymphoma in this study showed relatively characteristic features based on MRI; however, these features might be non-specific. The CI curves in this study showed a relatively rapid increase, reaching a maximum CI at 45-120 s, and a relatively rapid decrease in most lesions (14/17; 82.4%); on the other hand, the curves of 3 of the 15 lesions (17.6%) showed relatively rapid increase, sustenance of a plateau, and a gradual decrease thereafter. These patterns of CI curves may indicate characteristic features useful for distinguishing malignant lymphomas from other lesions.     

磁共振弥散加权成像在新生儿缺氧缺血性脑病的诊断价值

目的:以磁共振弥散加权成像(DWI)技术并与常规MR T1WI、T2WI结合应用,探讨DWI对新生儿缺氧缺血性脑病(HIE)的早期诊断价值。方法:对我院2004年1月~2010年1月临床确诊缺氧缺血性脑病的新生儿62例(4h~15天)进行DWI和常规T1WI、T2WI检查。结果:DWI出现高信号病灶59例,T1WI信号异常32例,T2WI信号异常13例。DWI高信号病灶多见于大脑皮层、侧脑室周围白质区及室管膜下,T1WI高信号以脑室周围白质区多见。出血性病变,在T1WI呈高信号,而DWI表现为无信号。结论:DWI适用于早期HIE,T1WI及T2WI在亚急性期、恢复期或随访应用显示病灶较好。     

MR imaging of epithelial cysts of the oral and maxillofacial region

The aim of the present study was to review the magnetic resonance (MR) appearance of primary epithelial cysts in order to distinguish the cysts from other possible lesions. MR images were obtained in 27 cases of epithelial cysts, including 7 odontogenic keratocysts, 3 dentigerous cysts, 1 glandular odontogenic cyst, 10 radicular cysts, 4 nasopalatine duct cysts, and 2 nasolabial cysts. In addition, contrast enhanced MR imagings were performed in 12 cases, including 3 odontogenic keratocysts, 1 dentigerous cyst, 1 glandular odontogenic cyst, and 7 radicular cysts. We obtained the following results on the basis of the above MR and contrast enhanced MR findings. (a) Odontogenic keratocysts had a predilection for intermediate-high signal intensity (SI) on T1-weighted images (WI) and heterogeneous low-high SI on T2WI. (b) Dentigerous cysts, glandular odontogenic cyst, radicular cysts and nasolabial cysts showed the same predilection with the SI, which were homogeneous intermediate SI on T1WI and homogeneous high SI on T2WI. (c) The MR images of the nasopalatine duct cysts, which showed homogeneous high SI on T1WI, were specific. (d) The Gd-T1WI would be useful in decisively differentiating odontogenic cysts, which showed rim-enhancement, from tumors consisting of solid components. In conclusion, we were able to obtain more information from the MR and contrast enhanced MR images than from conventional radiograph findings.     

软骨母细胞瘤MRI及X线平片和CT的表现特征

目的 研究软骨母细胞瘤的影像表现,探讨其MRI与X线平片、CT征象的对应关系.方法 分析16例经手术、病理证实的良性软骨母细胞瘤的影像资料,总结其MRI表现与X线平片、CT征象的对应关系.结果 16例软骨母细胞瘤均位于骨骺,大小为0.9 cm×0.8 cm×1.0 cm～4.8 cm×4.3 cm×5.1 cm,呈不同程度的分叶状.在T1WI上以等、低信号为主,T2WI上呈混杂信号,CT上为软组织密度,内见钙化和更低密度区.边缘呈长T1、短T2信号,在CT上表现为硬化边.MRI可见病灶周围有骨髓水肿,在X线和CT上表现为骨质硬化区.病灶邻近软组织肿胀.MRI显示骨膜异常9例,8例与病灶不相邻;X线和(或)CT显示骨膜新生骨6例.MRI显示关节积液12例,CT显示6例.MRI上病灶均呈不均匀强化,骨髓水肿、骨膜反应和软组织肿胀均见强化.软骨母细胞瘤在扩散加权成像(DWI)上呈等、高信号,在MR平扫中的等T1、等T2成分和长T1、长T2成分,以及骨髓水肿、骨膜反应和软组织肿胀在DWI上均呈高信号.结论 MRI和X线平片、CT从不同方面反映软骨母细胞瘤的病理改变,联合应用不同检查手段可更全面显示软骨母细胞瘤的特点.     

骨肉瘤的X线、CT及MRI比较分析(附61例分析)

目的:探讨原发性骨肉瘤的X线、CT和MRI表现及诊断价值.方法:经穿刺或手术病理证实的61例骨肉瘤患者,52例行X线检查,39例行CT检查,55例行MRI检查,其中23例行MRI动态增强检查.回顾性分析其影像学表现并与病理学表现进行对照分析.结果:本组61例骨肉瘤中成骨型13例,溶骨型21例,混合型27例.52例X线检...     

Adenomatoid odontogenic tumor: correlation of MRI with histopathological findings

Adenomatoid odontogenic tumor is a rare benign and odontogenic tumor that is frequently misdiagnosed as other odontogenic cysts and tumors on radiographic examination. To acquire additional information of adenomatoid odontogenic tumor, we performed magnetic resonance imagings (MRI) at a case of adenomatoid odontogenic tumor. The lesion was divided between the peripheral portion with a thick circular shape and the central portion with a round shape on the basis of the signal intensity (SI) of MRI. The peripheral portion showed intermediate SI contained multifocal no SI on T1WI, high SI contained multifocal no SI on T2WI, and heterogeneous enhancement on CE-T1WI. These multifocal areas corresponded to the numerous punctate radiopaque foci shown on computed tomography. The central portion showed homogeneous low SI on T1WI, homogeneous very high SI on T2WI, and no enhancement on CE-T1WI. Macroscopic examination revealed the round shaped lesion included one large cystic space correspondent to the central portion with a clear cystic wall correspondent to the peripheral portion on MRI. The MRI features corresponded to the macroscopic findings of the histopathological examination.     

长骨血管瘤的影像诊断

目的 分析长骨血管瘤的影像特征,旨在提高其诊断水平.方法 回顾性分析经手术病理证实的18例长骨血管瘤患者的X线平片(14例)、CT(9例)及MRI(6例).结果 18例长骨血管瘤中髓型10例、骨膜型5例、皮质内型3例.X线表现:髓型8例,其中3例表现为典型的蜂窝状,3例为溶骨性病灶周围骨质硬化明显,单纯溶骨、毛玻璃样密度各1例;骨膜型3例,表现为骨皮质增厚、硬化;皮质内型3例,表现为边界清晰的溶骨性病灶.CT表现:髓型6例,表现为溶骨膨胀型病灶5例,其中3例可见薄厚不一的硬化边,蜂窝状骨嵴影2例,骨皮质呈筛孔状1例,垂直于骨皮质的放射状骨膜增生2例;毛玻璃样密度1例.2例骨膜型表现为骨皮质均匀增厚1例,不规则骨膜增厚1例,局部髓腔狭窄消失.1例皮质内病变表现为病灶呈均匀软组织密度,局部皮质膨胀、增厚.MRI表现:2例显示髓腔内斑片状T1WI稍低信号,T2WI均呈稍高信号,边界清晰;1例T1WI及T2WI均呈等或稍低信号,病灶与正常组织分界不清;1例显示病灶突破局部骨皮质,肿物向外突出,外突肿物及相连髓腔部分T1WI呈稍低信号,T2WI呈高信号;2例显示骨膜增厚,其中1例呈等信号,1例无信号;2例周围肌肉组织内可见不均匀斑片状长T2信号,T1WI与肌肉组织呈等信号.结论 长骨血管瘤的囊性蜂窝状X线表现较为特征型;CT及MRI有助于长骨血管瘤的诊断.

Abstract：

Objective To explore the imaing features of hemangioma in the long bone and improve the diagnostic level of this disease. Methods The X-ray(14 cases), CT(9 cases) and MRI(6 cases)findings of 18 patientswith histologically proven hemangioma in the long bone after surgery were retrospectively reviewed. Results Ten tumors occurred in medullary cavity or bone end(medullary type),6 on the surface of bone (periosteal type) and 3 in cortex (intracortical type). X-ray findings: among 8 cases of medullary type, 3 showed honeycomb appearance, 3 lytic areas with sclerotic borders, one purely osteolyticchanges, and 1 frosted glass; 3 cases of periosteal type showed sclerosis and thickening of the underlying cortex; 3 cases of intracortical type showed well-defined osteolytic foci. CT findings: among 6 cases of medullary type, 5 appeared as expansile lytic lesion with uneven selerotic rim (3 cases)orhoneycomb appearance (2 cases), 1 cribriform appearance in the cortical bone, 2 periostealnew bone formation in vertical radiation pattern; 1 ground-glass appearance; among 2 cases of periosteal typeone showed regular cortical thickening, and the other irregular periosteal proliferation with marrowing of medullarycavity; 1 case of intracorticaltype showed density similar to that of soft tissue, with cortical thickening and expansion . MRI findings: 2 apeared as well-defined lesions with low signal intensity on T1WI and high signal intensity on T2WI; 1 appeared as ill-defined lesion with low to intermediate signal intensity on T1 WI and T2 WI. One showed breakthrogh of cortex and formation of soft tissue mass with low signal intensity on T1 WI and high signal on T2WI. Two showed thickening of periosteumwith intermediate signal intensity in one of them and very low signal intensity in the other. Two showed abnormal signal intensity in surrounding muscles, which was high on T2 WI and intermediate on T1 WI. Conclusions The soap-bubble or honeycomb appearance is the typical radiographic finding of hemangioma in long bone. CT and MRI can provide useful information for the diagnosis of hemangioma in long bone.     

长骨血管瘤的影像诊断

目的 分析长骨血管瘤的影像特征,旨在提高其诊断水平.方法 回顾性分析经手术病理证实的18例长骨血管瘤患者的X线平片(14例)、CT(9例)及MRI(6例).结果 18例长骨血管瘤中髓型10例、骨膜型5例、皮质内型3例.X线表现:髓型8例,其中3例表现为典型的蜂窝状,3例为溶骨性病灶周围骨质硬化明显,单纯溶骨、毛玻璃样密度各1例;骨膜型3例,表现为骨皮质增厚、硬化;皮质内型3例,表现为边界清晰的溶骨性病灶.CT表现:髓型6例,表现为溶骨膨胀型病灶5例,其中3例可见薄厚不一的硬化边,蜂窝状骨嵴影2例,骨皮质呈筛孔状1例,垂直于骨皮质的放射状骨膜增生2例;毛玻璃样密度1例.2例骨膜型表现为骨皮质均匀增厚1例,不规则骨膜增厚1例,局部髓腔狭窄消失.1例皮质内病变表现为病灶呈均匀软组织密度,局部皮质膨胀、增厚.MRI表现:2例显示髓腔内斑片状T1WI稍低信号,T2WI均呈稍高信号,边界清晰;1例T1WI及T2WI均呈等或稍低信号,病灶与正常组织分界不清;1例显示病灶突破局部骨皮质,肿物向外突出,外突肿物及相连髓腔部分T1WI呈稍低信号,T2WI呈高信号;2例显示骨膜增厚,其中1例呈等信号,1例无信号;2例周围肌肉组织内可见不均匀斑片状长T2信号,T1WI与肌肉组织呈等信号.结论 长骨血管瘤的囊性蜂窝状X线表现较为特征型;CT及MRI有助于长骨血管瘤的诊断.     

长骨血管瘤的影像诊断

目的 分析长骨血管瘤的影像特征,旨在提高其诊断水平.方法 回顾性分析经手术病理证实的18例长骨血管瘤患者的X线平片(14例)、CT(9例)及MRI(6例).结果 18例长骨血管瘤中髓型10例、骨膜型5例、皮质内型3例.X线表现:髓型8例,其中3例表现为典型的蜂窝状,3例为溶骨性病灶周围骨质硬化明显,单纯溶骨、毛玻璃样密度各1例;骨膜型3例,表现为骨皮质增厚、硬化;皮质内型3例,表现为边界清晰的溶骨性病灶.CT表现:髓型6例,表现为溶骨膨胀型病灶5例,其中3例可见薄厚不一的硬化边,蜂窝状骨嵴影2例,骨皮质呈筛孔状1例,垂直于骨皮质的放射状骨膜增生2例;毛玻璃样密度1例.2例骨膜型表现为骨皮质均匀增厚1例,不规则骨膜增厚1例,局部髓腔狭窄消失.1例皮质内病变表现为病灶呈均匀软组织密度,局部皮质膨胀、增厚.MRI表现:2例显示髓腔内斑片状T1WI稍低信号,T2WI均呈稍高信号,边界清晰;1例T1WI及T2WI均呈等或稍低信号,病灶与正常组织分界不清;1例显示病灶突破局部骨皮质,肿物向外突出,外突肿物及相连髓腔部分T1WI呈稍低信号,T2WI呈高信号;2例显示骨膜增厚,其中1例呈等信号,1例无信号;2例周围肌肉组织内可见不均匀斑片状长T2信号,T1WI与肌肉组织呈等信号.结论 长骨血管瘤的囊性蜂窝状X线表现较为特征型;CT及MRI有助于长骨血管瘤的诊断.     

Serial MR Imaging of Intramuscular Hematoma: Experimental Study in a Rat Model with the Pathologic Correlation

Objective

We wanted to demonstrate the temporal changes of the magnetic resonance imaging (MRI) findings in experimentally-induced intramuscular hematomas in rats and to correlate these data with the concurrent pathologic observations.

Materials and Methods

Intramuscular hematoma was induced in 30 rats. The MR images were obtained at 1, 4, 7 and 10 days and at 2, 3, 4, 6 and 8 weeks after muscle injury. The characteristic serial MRI findings were evaluated and the relative signal intensities were calculated. Pathologic specimens were obtained at each time point.

Results

On the T1-weighted imaging (T1WI), the intramuscular hematomas exhibited isointensity compared to that of muscle or the development of a high signal intensity (SI) rim on day one after injury. The high SI persisted until eight weeks after injury. On the T2-weighted imaging (T2WI), the hematomas showed high SI or centrally low SI on day one after injury, and mainly high SI after four days. A dark signal rim was apparent after seven days, which was indicative of hemosiderin on the pathology. The gradient echo (GRE) imaging yielded dark signal intensities at all stages.

Conclusion

Unlike brain hematomas, experimentally-induced intramuscular hematomas show increased SI on both the T1WI and T2WI from the acute stage onward, and this is pathologically correlated with a rich blood supply and rapid healing response to injury in the muscle. On the T2WI and GRE imaging, high SI with a peripheral dark signal rim is apparent from seven days to the chronic stage.     

Cardiac rupture in acute myocardial infarction: post-mortem MR imaging

We assessed acute myocardial infarction (AMI) with cardiac rupture in an autopsy using magnetic resonance (MR) imaging in vitro and histological staining. Cardiac MR imaging in vitro generated high resolution images of myocardial thinning, rupture, and epicardial hemorrhage. High signal intensity (SI) on T(1) weighted images (WI) and low SI on T(2)WI of the rupture site corresponded with acute myocardial necrosis, edema, and hemorrhage. A rupture site rich in erythrocytes after AMI might affect SI on T(1) and T(2)WI in cardiac MR imaging.     

Assessment of MRI and dynamic contrast-enhanced MRI in the differential diagnosis of adenomatoid odontogenic tumor

The radiographical differentiation of adenomatoid odontogenic tumor (AOT) from dentigerous cysts, calcifying odontogenic cysts, calcifying epithelial odontogenic tumors, odontogenic keratocysts and amelobastomas is sometimes difficult. We attempted to differentiate AOT from other lesions similar to AOT in radiographic findings using MRI. The MRI features of AOT in our three cases included homogeneous low SI in the cystic portion and homogeneous intermediate SI in the solid portion on T1WI, homogeneous high SI in the cystic portion and intermediate to slightly high SI in the solid portion on T2WI and enhancement of only the solid portion on CE-T1WI although none of the sequences included SI of calcifications. The contrast index curves in the three cases of AOT showed a gradual increase to 300 s, which signified a benign tumor. These MRI features were characteristic features of AOT and might be a basis for differentiating AOT from the above possible lesions in radiographic examinations.     

Magnetic resonance imaging of pilomatricoma

Two patients (a 16-month-old boy and a 53-year-old man) were referred for MR imaging of a small, subcutaneous nodule at the forearm. Plain films were available in one patient and showed a non-specific well-circumscribed lesion. Upon ultrasonography (1 patient), a nodular, well-circumscribed, hyperechoic lesion was seen. In both cases spin-echo (SE) T1-weighted images (T1W1) showed homogeneous, intermediate signal intensity (SI). On gadolinium-enhanced T1W1 (1 patient), no enhancement was observed. Both lesions showed predominant low-to-intermediate SI on T2WI. At histological examination characteristic findings of pilomatricoma were observed.     

超顺磁性氧化铁在肝脏局灶性病变中的定性研究

目的 探讨超顺磁性氧化铁（SPIO）增强MRI在肝脏局灶性病变的定性能力。材料与方法 43例怀疑肝占位者经常规MRI和Gd-DTPA增强后1－7后,行SPIO增强检查。其中31例经手术病理证实,12例经随访、实验室生化检查及临床资料证实。分析平扫MRI及SPIO增强后病灶的信号变化,并与Gd-DTPA动态增强结果相对照。结果 43例共12种病变、单发病灶21例,多病灶22例。包括原发性肝细胞肝癌22例,血管瘤5例,囊肿4例,转移性肝癌5例,肝硬化结节4例,局灶性结节增生（FNH）5例,其他病变6例。22例多发病灶中有8例合并1或2种病变。SPIO增强后,肝细胞肝癌T1WI为等或略高信号,T2WI为较高信号;血管瘤T1WI为较高信号,T2WI信号同平扫为高信号;囊肿T1WI、T2WI信号无改变;肝硬化结节T2WI为等信号同正常肝实质;FNH T2WI信号明显下降。其余病变的诊断SPIO增强不具有特征性,须与Gd-DTPA动态增强相结合。结论 SPIO具有一定的定性能力Gd-DTPA增强相结合,可帮助提高肝局灶性病变诊断和鉴别诊断的准确性。     

邻关节骨囊肿的CT、MR表现特点

目的探讨邻关节骨囊肿的影像学诊断。方法本组共36例经病理证实的邻关节骨囊肿病例,其中19例做了CT扫描检查,17例做了MRI检查,5例(5/36)同期做了CT和MRI检查。结果邻关节骨囊肿的CT上主要表现呈圆形或卵圆形的低密度病灶,边缘可见硬化,单房或多房,骨皮质可有断裂,病灶多位于关节软骨下,三维重建显示病灶与关节腔相通;MRI上主要表现呈类圆形或不规则形病灶,T1WI上为均匀的低信号,T2WI上为均匀的高信号,在STIR图像中异常信号未被抑制,病灶位于关节软骨下,增强扫描病灶边缘环形强化;病灶与关节相通。结论CT和MR是检测这类病变的重要手段。     

Case report: magnetic resonance imaging of vaginal malignant melanoma

We report two cases of vaginal melanoma with magnetic resonance imaging findings. The first melanoma was a bilobular polypoid mass with melanotic and amelanotic components, which arose from the lateral wall of the vaginal canal. The melanotic melanoma showed high signal intensity (SI) on T1-weighted images and low SI on T2-weighted images, which was not suppressed by a fat-saturated sequence. Another melanoma showed a pale brown polypoid mass in the vagina, which revealed intermediate SI on T1-weighted images and high SI on T2-weighted images. On fat-suppressed images, both tumors were more clearly demonstrated with high SI.     

Osteoid osteoma treated with percutaneous radiofrequency ablation: MR imaging follow-up

PURPOSE: We evaluated follow-up magnetic resonance (MR) images for osteoid osteoma treated with percutaneous radiofrequency ablation (RFA). MATERIALS AND METHODS: Sixteen patients with osteoid osteoma treated with RFA underwent follow-up MR imaging. The protocol included T1, T2 and contrast-enhanced (CE) T1-weighted images with fat saturation at each visit immediately for 17 months after the treatment. MR images were jointly reviewed by two radiologists, regarding the appearance of treated areas, presence of complications, and the best sequence for visualization of signal intensity (SI) changes. The therapeutic response was evaluated to be a clinical success with the relief of pain. RESULTS: The treated areas had a target-like appearance on MR images: a central ablated zone (Z1) surrounded by a band (Z2), and a peripheral area (Z3). Z1 was a non-enhancing, hypointense core on T1, T2WI. Z2 was a well-enhancing, hyperintense rim on T2WI. Z3 was less hyperintense and less enhanced than Z2. All nidi were within Z1. This appearance became evident from 1 week to 1 and 2 months. Following up after 2 months, Z2 showed progressive inward enhancement from the periphery, resulting in almost complete enhancement of Z1 and Z2 with a diminishing size. Z3 gradually showed a decrease in signal change and enhancement. No complications were found. CE-T1WI was the best for visualizing SI changes. The clinical success was achieved in all patients except for one patient with a recurrence at 17 months following treatment that had a second ablation. CONCLUSION: MR imaging demonstrated a characteristic appearance and subsequent changes of treated areas for osteoid osteoma following RFA.