应力性骨折的早期低场强MRI与DR诊断分析

目的：通过对应力性骨折的DR与低场强MRI表现的对比,及分析应力性骨折的解剖学和生物力学特征,提高对应力性骨折早期的低场强MRI诊断的准确性。方法：回顾性分析经临床随访或病理证实29例不同部位应力骨折患者的MRI及DR图像。结果：29例中,胫骨12例（中上段为主）,股骨下段3例,胫骨上段和股骨下段同时发病3例,髂骨、耻骨、坐骨及股骨头颈部、股骨上段各2例,跖骨2例,腓骨中上段2例。MRI均可见骨髓腔内斑片状不均匀长T1、长T2水肿信号,范围远较DR片广泛,边界模糊;7例骨皮质周围见环形或半环形长T1、长T2骨膜水肿信号;6例可见隐匿骨折线;冠、矢状位表现为髓腔内斜形或横形线条状长T1、短T2信号影,其中骨皮质中断4例;10例可见骨皮质增厚,呈长T1、短T2信号;软组织肿胀呈弥漫性长T1、长T2信号。结论：MRI能够更敏感地发现早期应力性骨折,为诊断和判断骨折愈合情况提供更多信息。     

应力性骨折的影像学诊断

目的研究不同部位应力性骨折的影像学特点并分析其生物力学基础。方法搜集20例应力性骨折患者的X线、CT、MRI、发射型计算机体层显像(ECT)资料，分析其影像学表现及其与骨骼生物力学薄弱区的相关性。结果20例中，胫骨14例、跖骨2例、肋骨1例、股骨颈并双侧肋骨多发性骨折1例、股骨下段1例、腓骨1例。2例早期应力性骨折X线上表现为较具特征性的“灰色骨皮质征”；修复期骨痂呈球形或不规则形生长，骨膜反应明显，2例可见“双皮质征”；骨折局部愈合，典型表现为“扣征”。CT扫描能清晰显示骨质改变和软组织水肿；MRI上骨痂生长表现为T1WI低信号，T2WI稍高信号；骨髓水肿范围较平片及CT所见大，T1WI呈低信号，T2WI呈高信号；骨折线呈长T1、短T2信号；ECT表现为骨折处放射性浓聚。应力性骨折发生部位具有一定特征性，好发于骨骼生物力学上的薄弱区。结论应力性骨折的发生部位及影像学表现均具有一定的特征性，X线平片仍是诊断应力性骨折的首选方法，CT与MRI对于鉴别诊断具有较高价值，ECT对显示病变敏感性较高，但无特异性。     

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.     

左肱骨恶性纤维组织细胞瘤一例

患者男,28岁.左上肢疼痛10个月,局部软组织逐渐出现肿胀.2 d前摔倒后X线片示：左肱骨中上1/3骨折.CT扫描：左肱骨中、上1/3骨皮质连续性中断,周围软组织肿胀.MRI表现：左肱骨上段呈明显长T1低信号.骨皮质线不连续,周围可见不规则软组织肿块包绕,长径约11 cm,边界欠清晰,T1WI呈等信号,T2WI呈等略高混杂信号.Gd-DTPA增强扫描：软组织肿物呈轻至中度不均匀强化,骨髓腔内亦不均匀强化,病骨长8.6 cm.MR诊断：左肱骨上段恶性肉瘤伴病理性骨折（图1～3）.骨折复位术时取部分肿块组织,     

32例膝关节应力性骨髓水肿MRI诊断分析

目的分析膝关节应力性骨髓水肿的MRI表现,提高对膝关节应力性骨髓水肿的认识。方法回顾性分析32例训练后X线片阴性而MRI发现膝关节骨髓水肿的病例,分析应力性骨髓水肿的MRI表现。结果 44个膝关节发现应力性骨髓水肿共52处,在MRI上表现为骨髓腔内片状、小斑片状异常信号影;病灶在T1WI为稍低或等信号,在T2WI上为稍高或等信号,在压脂T2WI病灶为明显高信号影,且边界和范围较T1WI、T2WI显示更清楚。9例MRI复查见水肿信号范围明显缩小、部分小的水肿信号消失,未见骨折征象。结论 MRI能够敏感地发现应力性骨髓水肿,是早期诊断应力性骨损伤的重要影像学方法。     

64层CT及MRI诊断隐匿性骨折的临床价值

目的:探讨多层CT及MRI诊断隐匿性骨折的临床价值.材料和方法:回顾性分析经DR检查阴性而64层CT或MRI诊断骨折的51例外伤患者的多层CT及MRI表现.51例均行64层CT检查,28例同时行MRI检查.结果:64层CT显示骨皮质/骨小梁中断47例(47/51).22例(22/28)MR T1WI见骨皮质下或松质骨内不规则线状、条状低信号带,T2WI对应于T1WI低信号带仍可见形态相似的低信号;28例(28/28)MR T2WI对应于T1WI低信号带或64层CT显示的骨折线周围均见片状高信号水肿;6例(6/28)MR T1WI未见低信号带,64层CT显示骨皮质中断;4例(4/28)MRT1WI见松质骨内低信号带,64层CT检查未明确骨折线.结论:多层CT显示骨皮质细微骨折优于MRI,可作为隐匿性骨折的首选检查方法;MRI对部分多层CT显示不明确的松质骨骨折的诊断有帮助.     

长骨孤立性浆细胞瘤的影像学表现

目的：探讨四肢长骨骨孤立性浆细胞瘤的影像学表现。方法：回顾性分析11例经手术或穿刺活检病理证实的四肢长骨骨孤立性浆细胞瘤的临床及影像学资料,分析其影像学征象。观察指标包括骨质破坏形态、骨皮质改变、骨膜反应、MRI信号特征、瘤周骨髓水肿、软组织改变以及MRI增强改变等。结果：11例肿瘤发生在肱骨4例,股骨7例。11例在X线片和CT上均呈溶骨性骨质破坏伴有轻度的膨胀,边界较清。10例骨皮质变薄,1例骨皮质增厚。9例可见骨皮质呈虫蚀样或锯齿状骨质破坏,未见骨膜反应。所有病例均未见瘤周骨髓水肿,且均可见软组织侵犯,3例可见明显的软组织肿块。与肌肉信号相比,10例T1WI表现为稍高信号,1例呈等信号,11例T2WI表现为高信号。MRI增强扫描,大部分病例表现为明显均匀性强化,仅1例中央可见无强化区。结论：四肢长骨骨孤立性浆细胞瘤的影像学表现具有一定的特征性,X线、CT和MRI综合评价有助于提高四肢长骨骨孤立性浆细胞瘤的诊断准确性。     

隐性骨折的MRI分析

目的 探讨隐性骨折的MRI诊断价值。方法 16例急性外伤患者均行X线平片检查及MRI检查,3例同时行CT检查,受伤部位分别为股骨髁3例,胫骨近端8例,胸腰段椎体5例。结果 本组16例X线平片均未见骨折征像;11例（11／16）股骨髁及胫骨近端受伤病例中3例（3／16）T1WI见骨皮质下线状信信号带改变,8例（8／16）显示由关节面下向骨干走行的不规则条状、紊乱低信号改变;在T2WI上对应于T1WI低信号区仍表现为相应形状的低信号,且在低信号周围可见高信号水肿改变;T1脂肪抑制序列扫描显示水肿带信号明显增强、增宽。2例股骨髁和1例胫骨近端病例同时行CT检查,示周围软组织肿胀,未见确切骨折征像。5例（5／16）胸腰段椎体MR T1WI、T2WI示椎体中央有水平方向走行的线状低信号带,在T2WI低信号周围可见高信号水肿。结论 MRI能够早期确诊隐性骨折,若患者临床症状、体征不能除外隐性骨折,X线检查后行MRI应为最佳的检查手段。     

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.     

Stress fractures: MR imaging

Five cases of stress fracture were studied with high-field-strength magnetic resonance (MR) imaging. In all cases, MR images showed bandlike areas of very low signal intensity in the intramedullary space, which were continuous with the cortex. These findings corresponded in location to the sites of fracture or new bone formation noted on radiographs. Surrounding areas of decreased signal intensity in the marrow space were also consistently seen on T1-weighted images. In three cases, prominent intramedullary areas of high signal intensity were noted on T2-weighted images obtained within 3 weeks of the onset of symptoms. Juxtacortical and/or subperiosteal areas of high signal intensity were also seen on T2-weighted images in two cases. Characteristic MR findings may distinguish stress fracture from occult intraosseous fracture.     

Longitudinal stress fractures of the tibia: diagnosis by magnetic resonance imaging

 Objective. Previous works describe magnetic resonance (MR) imaging characteristics of stress fractures. Diagnosis of the atypical, longitudinal type of stress fracture has been reported using computed tomography (CT). This report focuses on MR imaging of longitudinal stress fractures of the tibia. Materials and methods. Six cases are presented in which a longitudinal linear abnormal marrow signal was detected in the middle and distal parts of the tibial shaft. Five patients were imaged using a 1.5 Tesla MR unit. Axial, sagittal and coronal T1 and T2-weighted or fat suppressed proton density fast spin echo images were obtained in all but one patient. One patient was imaged using a 0.5 Tesla MR unit with axial and coronal T1- and T2-weighted sequences. Initial conventional radiographs seen at clinical presentation were interpreted as normal in all cases. Two patients underwent radionuclide bone scan, and one patient was imaged with CT prior to MR imaging. Results. In each instance, MR imaging demonstrated linear marrow signal abnormalities orientated along the long axis of the tibial shaft. Endosteal and periosteal callus was identified on axial images. In all cases, MR imaging clearly demonstrated a fracture extending through one cortex with abnormal signal in both the marrow cavity as well as adjacent soft tissues indicating edema. Conclusion. MR imaging was shown to be excellent for demonstration of fracture lines, callus, and marrow and soft tissue abnormalities seen in association with longitudinal stress fractures.     

放疗后脊柱MRI表现

探讨放疗后脊柱骨髓ＭＲＩ的特征。材料与方法；本组５５例脊柱放疗后患者，放疗剂量２１００－７５００ｃＧｙ，各病例开始放疗后ＭＲ检查之间的间隔时间不等，最短的是７周，最长的是２０年。结果：ＭＲＩ表现为：Ｔ１ＷＩ像椎体呈明显高信号改变，且信号均匀，与非照射野的脊柱分界清晰；Ｇ２ＷＩ像呈均匀的稍高信号；ＳＴＩＲ或Ｔ１ＷＩ抑脂成像显示椎体呈明显低信号改变。     

Transient bone marrow edema of the talus: MR imaging findings in five patients

OBJECTIVE: To describe the MR findings of transient bone marrow edema (TBME) of the talus and to address the differential diagnostic considerations. DESIGN AND PATIENTS: The imaging findings of TBME of six tali were retrospectively reviewed in five patients with a clinical history of pain without trauma. Inclusion criteria were MR imaging findings that, when compared with clinical data and results of follow-up assessment, allowed the diagnosis of TBME. MR imaging, standard radiography, and bone scintigraphy were performed. The images were reviewed with particular attention to the pattern and distribution of abnormal marrow signal intensity as well as associated findings. RESULTS: In four cases the entire talus was involved, and in two cases only a portion of the bone was affected. No fractures were detected. MR imaging demonstrated diffuse decreased signal intensity of the marrow on T1-weighted images with corresponding increased signal intensity on T2-weighted images. In all six cases MR imaging detected associated findings, which included joint effusion and soft tissue edema. All patients improved clinically with conservative therapy over a period of 6 months to 1 year. CONCLUSIONS: Although unusual, TBME can involve the talus. Marrow edema without evidence of a fracture and in the absence of history of trauma is a characteristic MR imaging feature, allowing confident diagnosis and institution of conservative therapy.     

Bone abnormalities of the knee: prevalence and significance at MR imaging

Focal abnormal signal intensity within the distal femoral condyles or proximal tibial plateaus is frequently seen on T1- or intermediate-weighted magnetic resonance (MR) images of the knee. To characterize the prevalence and significance of these findings better, a retrospective study of MR imaging of the knee, performed on the first 434 consecutive patients at a primarily outpatient community MR imaging center, was undertaken. A signal intensity loss demonstrated on images with a short echo time (20 or 25 msec) was divided into three types based on morphologic criteria. A type 1 finding was a diffuse, often reticulated signal intensity loss in the metaphyseal and epiphyseal regions of bone. A type 2 loss was associated with an interruption in the smooth, black cortical line. A type 3 finding was a profound signal intensity loss primarily restricted to the immediate subcortical region. Seventeen percent of all cases revealed a type 1 or 2 loss that may have been compatible with acute bone injuries. These bone lesions were frequently associated with tears of the anterior cruciate ligament and contralateral collateral ligament, but infrequently these lesions were detected with plain radiography and arthroscopy. When associated with a weight-bearing cortex, bone injuries detected with MR imaging may explain clinical symptoms of pain on weight bearing, and type 1 injuries may represent regions of bone at increased risk for the subsequent development of insufficiency fractures if the bone is not adequately protected during trabecular healing.     

MR imaging of osteoradionecrosis of the mandibula following radiotherapy for head and neck cancers

Magnetic resonance (MR) images of 13 patients with osteoradionecrosis of the mandibula were analyzed. Abnormalities were noted in all patients and could be classified into three groups. In nine patients, MR signals were homogeneously low in intensity on both T1 weighted images (T1WI) and T2 weighted images (T2WI), suggesting fibrosis of bone marrow. These nine patients had suffered radiologically and/or clinically overt osteoradionecrosis more than ten months previously, and inflammatory symptoms had settled down by the time of MR study. Two patients showed low signal intensity on T1WI and an area of inhomogeneous high intensity in a diffuse area of low signal intensity on T2WI, suggesting acute inflammation in the irradiated fibrous bone marrow. Both patients suffered pathologic fracture due to osteoradionecrosis and showed severe inflammatory symptoms at the time MR study. In one of the two patients, these pathologic changes were confirmed in surgically excised mandibulectomy specimens. The other two patients showed homogeneous low signal intensity on T1WI and high signal intensity on T2WI, a finding that may be due to slight inflammation. However, in one of the two patients, this signal feature possibly indicated loose fibrosis with marked cellularity.     

磁共振弥散加权成像对急性一氧化碳中毒的诊断价值

目的 :评价磁共振弥散加权成像对急性一氧化碳中毒的诊断价值。方法 :回顾性分析 6例急性一氧化碳中毒的MRI表现 ,分别采用SE序列T1WI、T2 WI、FLAIR和DWI。结果 :急性一氧化碳中毒MRI表现为两侧大脑皮层、皮层下区及苍白球T1WI等信号、T2 WI高信号 ,所有异常信号均呈两侧对称性改变。结论 :磁共振弥散加权成像对急性一氧化碳中毒具有重要诊断价值。     

质子脂肪抑制序列在四肢隐性骨折中的诊断价值

目的探讨质子脂肪抑制序列(PDFASAT)在四肢隐性骨折中的诊断价值。方法31例四肢关节外伤患者在伤后45d内均行X线平片及多序列高场强(1．5T)MR检查，检查序列包括快速SE T1WI、T2WI，PDF ASAT等。受伤部位为膝关节21例，髋关节6例，肘关节1例，肩关节2例，踝关节1例。结果31例X线平片均未见明显骨折征象。MR检查发现：21例(21／31)膝关节受伤病例中腓骨近端隐性骨折10例，胫骨近端4例，股骨髁7例；6例(6／31)髋关节受伤病例中粗隆问隐性骨折2例，股骨颈隐性骨折2例，髋臼隐性骨折2例；1例(1／31)肘关节受伤病例显示肱骨远端隐性骨折；2例(2／31)肩关节受伤病例显示肱骨近端隐性骨折；1例(1／31)踝关节受伤病例显示腓骨远端隐性骨折；MR信号主要表现为T1WI、T1WI呈细线状、条带状低信号影，PDFASAT呈更清晰锐利的细线状、条带状高信号影，PDFASAT序列更易认识辨别。结论MRI能发现早期至慢性期隐性骨折的存在，如临床强烈提示骨折可能而X线检查阴性者，MR检查的PDFASAT序列是明确诊断的最佳序列。     

Bone bruises: MR characteristics and histological correlation in the young pig

PURPOSE: To correlate magnetic resonance (MR) signal characteristics of bone bruises with histological findings. MATERIALS AND METHODS: In 14 tibiae of young pigs, bone bruises were created in the proximal tibial metaphysis. The signal intensity seen on the MR images were correlated with histological findings. The following findings were evaluated: (a) changes of signal intensity on the tibiae; (b) changes of histology on the tibiae; and (c) changes of (a) and (b) on follow-up examinations. RESULTS: We observed three types of injuries on T1-weighted images: focal or diffuse low signal, normal signal and linear low signal intensities. Severe hemorrhagic areas showed low signal intensities on all sequences of MR imaging. Fast spin-echo (FSE) T2-weighted images showed a more distinct low signal intensity than T1-weighted images. FSE short tau inversion recovery (STIR) and FSE fat saturated (FSE-FS) T2-weighted images showed similar signal intensities with FSE T2-weighted images. FS T1-weighted enhanced images showed low signal intensities with variable enhancements. Upon histological examination, hemorrhages and edemas were prominent at the subcortical areas of the contusion sites. The areas of dense, low signal intensities in all imaging sequences showed signs of severe hemorrhage. The areas of diffuse low signal and enhanced areas showed mixed areas of hemorrhages and edemas. Follow-up MR imaging showed evolution of the processes of hemorrhages and edemas with fatty marrow changes. CONCLUSIONS: MR imaging can depict changes in the bone marrow resulting from direct injury to the bone. MR imaging is a useful tool for evaluating the evolution of bone bruises.