Hypervascular hepatic focal lesions: spectrum of imaging features

Detection and characterization of liver lesions often present a diagnostic challenge to the radiologists. Liver lesions may be classified as hypovascular and hypervascular based on degree of hepatic arterial blood supply. Common hypervascular liver lesions include hemangioma, focal nodular hyperplasia, hepatocellular adenoma, hepatocellular carcinoma, fibrolamellar carcinoma, and metastases from primary tumors such as islet cell tumor, carcinoid, renal cell carcinoma, melanoma, and thyroid carcinoma. In this review article, we discuss the spectrum of imaging features of hypervascular liver lesions.     

股骨头缺血性坏死的基因治疗与影像学观察

股骨头缺血性坏死是骨科难治疾病之一,如早期得不到及时有效的治疗,可引起股骨头塌陷、变形,最终导致髋关节功能障碍.基因治疗是新近发展起来的一项新技术,随着分子生物学的发展和基因转移技术的成熟,治疗性血管生成为股骨头缺血性坏死的治疗提供了新的思路.综述股骨头缺血性坏死的基因治疗现状及影像学检查的作用.     

Magnetic resonance imaging of avascular necrosis of the femoral head

This study investigates the role of magnetic resonance imaging (MR) in identifying avascular necrosis (AVN) of the femoral head and in monitoring its therapy. The detection of AVN, particularly in its early stages, is imperative to give therapeutic intervention the best opportunity for successful management. The results of magnetic resonance imaging are compared with those of the standard diagnostic modalities in evaluation of patients with the lesion. Examinations were performed at 0.12 T with a repetition time (TR) of 143 ms and times to echo (TE's) of 10 or 20 ms. This study represents a retrospective review of 90 hips which were examined in 45 consecutive patients. Of these, 52 hips were biopsied as part of treatment. MR was shown to be sensitive in the detection of AVN. Comparison of MR with radionuclide imaging showed comparable sensitivity and specificity. MR was also noted to be sensitive in the detection of early AVN. Preliminary results suggest that MR can monitor treatment of the affected hip, and may even be able to predict patient response to therapy. Although further work is necessary to determine the role of MR in the evaluation of the patient presenting with hip pain, MR is a sensitive method in detecting AVN and in monitoring its course in patients suspected of having the disease.     

Idiopathic bone marrow edema lesions of the femoral head: predictive value of MR imaging findings.

PURPOSE: To determine the frequency of several subchondral magnetic resonance (MR) imaging features observed in bone marrow edema lesions of the femoral head and to determine their value for differentiation of irreversible from transient lesions. MATERIALS AND METHODS: The authors reviewed MR images of 72 femoral head lesions in 42 men and 25 women (median age, 48 years) with equivocal radiographic findings and bone marrow edema seen at MR imaging (T1- and T2-weighted images in all patients and contrast material-enhanced T1-weighted images in 39 patients). Follow-up MR images showed 57 lesions to be transient and 15 to be irreversible. The presence and size of subtle subchondral features observed on initial MR images were compared for both types of lesion. RESULTS: Lack of any additional subchondral change on T2-weighted or contrast-enhanced T1-weighted images had 100% positive predictive value for transient lesions. For irreversible lesions, presence of a subchondral area of low signal intensity at least 4 mm thick or 12.5 mm long had positive predictive values of 85% and 73%, respectively, on T2-weighted images and 87% and 86%, respectively, on contrast-enhanced T1-weighted images. CONCLUSION: Careful assessment of subchondral changes enables confident differentiation between early irreversible lesions and transient bone marrow edema lesions.     

股骨头缺血坏死与伴有骨髓水肿的一过性骨质疏松的MRI表现及其研究进展

股骨头由于其血供特点,很易于发生缺血坏死。股骨头缺血性坏死是引起髋部疼痛的常见病,是渐进性疾病,主要累及年轻人,影像检查的目的是对其进行早期诊断,评价其坏死程度。一过性骨质疏松属自限性疾病,一过性疾病。骨髓水肿是以上两种疾病的主要MRI表现,笔者就有关问题综述如下。     

股骨头缺血坏死的分期与早期影像学诊断

目的 研究股骨头缺血坏死（ＡＮＦＨ）的分期、早期影像学表现及诊断价值。方法 ６２例双侧股骨头行Ｘ线、ＣＴ及低场ＭＲＩ检查,并对其影像学改变进行分期及等级稚和Ｈ检验和敏感性对照。结果 全部患者Ｘ线平片均诊断为早期ＡＮＦＨ,共９１个部位。其中Ⅰ期４６个,表现为骨疏松及骨硬化;Ⅱ期４５个,为骨硬化和囊状透亮区。ＣＴ发现５６例早期ＡＮＦＨ,共８６个部位。其中Ⅰ３４个,表现为星芒结构变形、骨疏松和骨硬化;Ⅱ     

股骨头无菌坏死的MRI诊断

目的 研究MRI早期诊断股骨头无菌坏死（ANFH）的临床价值。方法 收集30例做过MRI、X线平片和CT检查的ANFH的临床资料进行分析和比较。结果 X线平片发现早期ANFH24个部位，其中I期9个，表现为骨质疏松及骨硬化；Ⅱ期15个部位，表现为骨硬化和囊状透亮区。CT表现早期病变19个，其中Ⅰ期11个，表现为星芒状结构变形骨疏松和骨硬化；Ⅱ期8个，表现为骨硬化和透亮区。MRI发现32个早期病变，其中Ⅰ期20个，表现为斑点状T1WI低信号或高信号；Ⅱ期12个，表现为T1WI不规则低等高信号。经统计学卡方检验，MRI和X线平片的检诊敏感性有显差异。结论 MRI可早期发现ANFH，敏感性和诊断价值明显优于X线平片和CT。     

Avascular necrosis of the femoral head: high-field-strength MR imaging with histologic correlation

Magnetic resonance (MR) images, contact radiographs, and histologic sections of six femoral head specimens with avascular necrosis were correlated. A low-signal-intensity band or ring represented the repair tissue interface surrounding a high-signal-intensity necrotic marrow segment. Large segmental areas of low signal intensity were observed on T1-weighted images when the lesion consisted of necrotic bone with amorphous marrow debris and adjacent thickened trabecular bone with mesenchymal repair tissue infiltration. On intermediate-weighted images, however, mesenchymal repair tissue, which was located inferior to the necrotic zone, increased markedly in signal intensity, permitting distinction from low-intensity necrotic bone with amorphous marrow debris. When trabecular thickening with collapse predominated, segmental areas of low signal intensity with both sequences were found. MR signal intensities used in combination with anatomic configuration and location may provide information of potential therapeutic importance regarding tissue composition and stage of disease.     

股骨头无菌坏死弥散加权成像的临床应用

目的 对股骨头无菌性坏死(FHN)患者的磁共振弥散加权成像(DWI)的影像学特征进行总结分析,为FHN的诊断提供依据.方法 对22名股骨头正常者及42例FHN患者的磁共振信号分布及表观弥散系数(ADC)进行分析比较.结果 股骨头正常者T1加权像及T2加权像呈均匀高信号,DWI为低信号;FHN患者的T1加权像呈低信号和稍低信号,T2加权像呈不均匀高信号和稍高信号,DWI呈不均匀高信号.股骨头正常者、FHN患者病变周围区和中央区的ADC分别为(0.000～0.036)×10-3mm2/s、(0.111～0.311)×10-3mm2/s和(0.845-1.397)×10-3mm2/s,三者间的差异具有统计学意义(F=1384.28,P＜0.05).结论 FHN患者的DWI信号分布及ADC与股骨头正常者相比,具有明显的特异性,可用于对FHN患者的明确诊断,并可根据ADC的测量对骨髓病变进行量化分析.     

MR imaging of femoral head avascular necrosis with STIR sequence

The uncomplicated bone necrosis is usually demarcated by reactive interface (RI). To analyze signal characteristics of RI, MR imaging of the hip was done using short TI IR (STIR) as well as short/long TR pulse sequences at 0.22 tesla. On STIR sequence the RI was observed as a high-signal line or ring with the shape identical to that of short TR image. The double line sign was not seen in early stage. The best explanation of high signal intensity of RI on STIR is that it has prolonged T1 and T2 secondary to high water content. It is concluded that STIR is an unique way to demonstrate RI in early osteonecrosis.     

Malignant round cell tumours of bone: atypical clinical and imaging features

Objective.To describe the clinical, radiological and MRI features of six atypical cases of histologically proven appendicular Ewing sarcoma/ primitive neuroectodermal tumour (PNET). Design. Retrospective review of case notes and available imaging was carried out. Patients. Six patients (4 male, 2 female; mean age 27years, range 19–44 years), presenting over a 77-month period, were identified from the Bone Tumour Register. All had unusual clinical and imaging features for Ewing sarcoma/PNET. Results and conclusions. Four tumours were centred on the distal femoral metaphysis, one in the proximal tibial metaphysis and one in the distal tibial metaphysis. Plain radiographs were available in four cases and showed minor cortical changes. MRI demonstrated a relatively small, eccentrically located intraosseous component with a large, eccentric extraosseous component. Extension into the epiphysis was seen in three cases and into the adjacent joint in two cases. Intraosseous ”skip” metastases were present in three cases. The clinical and imaging features were atypical for conventional intraosseous Ewing sarcoma/PNET and the exact site of origin (intraosseous, periosteal or soft-tissue) was unclear. Received: 6 December 1999 Revision requested: 7 February 2000 Revision received: 20 July 2000 Accepted: 4 August 2000     

MR imaging of iliopsoas bursitis and concurrent avascular necrosis of the femoral head

The magnetic resonance (MR) features of iliopsoas bursitis secondary to an inflammatory arthropathy of the hip are described in a patient with concurrent avascular necrosis of the femoral heads. The MR findings of avascular necrosis were demonstrated on one side where radiography, bone scan, and CT were negative.     

The role of MR imaging in avascular necrosis of the femoral head

Due to the pattern of its blood supply, the femoral head is particularly vulnerable to avascular necrosis (AVN). Nontraumatic AVN is a devastating disorder affecting young patients, and despite treatment it normally follows a progressive course toward a destructive osteoarthropathy. Magnetic resonance (MR) imaging is currently used in major classification systems solely for early detection of femoral head AVN when plain radiographs are normal. More recent data have shown that MR imaging may improve staging, investigate radiologically occult collapse, depict other causes of disability and pain, assess prognosis, and evaluate treatment. This article reviews the established and evolving role of MR imaging in patients at risk or with known femoral head AVN.     

股骨头缺血性坏死的影像学分析

目的探讨股骨头缺血性坏死(ANFH)的X线、CT表现及临床价值。方法回顾性分析36例ANFH患者影像学资料,并进行总结比较。结果 36例中双侧发病13例,占36%;单侧发病23例,占64%。X线检查:股骨头未发现异常6例,诊断为Ⅰ期1例,Ⅱ期9例,Ⅲ期12例,Ⅳ期8例;CT检查:股骨头未发现异常1例,CT诊断为Ⅰ期4例,Ⅱ期8例,Ⅲ期15例,Ⅳ期8例。结论 X线片是诊断ANFH最基本、最经济、最简便的方法,但对早期病变易漏诊,对中、晚期AFHN可明确诊断。CT具有较高的分辨率,能显示病理Ⅱ期ANFH,对于ANFH的早期诊断和分期比X线片优越。     

骨矿物盐在兔激素性股骨头坏死过程中的变化

目的 探讨骨矿物盐在激素性股骨头坏死(GANFH)发病过程中改变的意义.方法 选用32只健康成年新西兰大白兔,随机分为正常对照组、激素造模组.激素造模组每周两次臀肌注射醋酸氢化可的松注射液8.0mg/kg,共注射8周.两组分别于处理的2、4、6、8、12周测定股骨头及股骨颈的骨密度,并检测血清钙、磷水平,同时观察其体重、精神、毛发情况等一般指标变化.结果 与正常对照组比较,激素造模组动物造模1周后体重开始进行性下降,股骨颈骨密度从第2周开始、股骨头骨密度从第4周开始显著下降(P<0.05,P<0.01),且激素造模组12周时股骨颈骨密度明显低于第8周时(P<0.05).与正常对照组比较,激素造模组血清钙、磷水平均从第2周开始即显著显著降低(P<0.05,P<0.01),且激素造模组12周时血清钙水平明显低于第8周时(P<0.05).结论 激素性股骨头坏死与股骨头、颈骨密度降低及骨矿物盐平衡的破坏有关.     

影像学预测股骨头坏死塌陷研究进展

股骨头坏死后塌陷与否是股骨头幸存的临界点,也是早期治疗疗效评价的重要依据。本文对股骨头坏死塌陷的机制及影像学预测方法及其价值作一初步总结。     

Chemical-shift MR imaging of the femoral head: an in vitro study of normal hips and hips with avascular necrosis

To study the conventional and chemical-shift MR images of fatty, hemopoietic, and ischemic bone marrow, four normal femurs from autopsies and six femoral heads from total hip replacement done for avascular necrosis (AVN) were imaged with a small-bore 1.4-T MR unit. T1- and T2-weighted spin-echo images, fat- and water-selective spin-echo images, and out-of-phase images were obtained. The specimens were then sectioned, radiographed, and studied histologically. The capital epiphysis and greater trochanter in normal femurs had the highest signal on T1-weighted, fat-selective, and out-of-phase images owing to their high fat content. Fat-selective and water-selective images accurately depicted regions of fat and water, whereas T1-weighted, T2-weighted, and out-of-phase images were misleading in some cases. On T2-weighted images, a double line consisting of a rim of low signal with a high-signal inner border was noted surrounding AVN lesions. Histologic correlation showed that the low-signal outer rim was due to sclerotic bone, while the high-intensity inner border was due to granulation tissue and/or chondroid metaplasia. Fractures within the six AVN lesions were best seen on T2-weighted images, but these could not be distinguished from granulation tissue. On T2-weighted images, the weight-bearing cartilage had lower signal in five of six femoral heads with AVN. We conclude that the MR appearance of AVN reflects its complex histopathology. Direct spin-echo chemical-shift imaging can help correlate MR images with histology by providing information not available from conventional or out-of-phase images.     

股骨头坏死骨髓水肿研究进展

<正>股骨头坏死(osteonecrosis of femoral head,ONFH)是一种骨科临床常见疾病,目前其病因病机尚不清楚,且致残率高,现已成为骨科疑难病种之一。在MRI出现之前,对股骨头坏死的诊断主要以X线片、CT及ECT为主,这些诊断方式各有优势     

Contrast-enhanced imaging features and differentiation of benign and malignant focal splenic lesions

To assess the value of imaging features for differentiating malignant from benign focal splenic lesions, 79 pathologically proved cases with contrast-enhanced CT or MRI were retrospectively studied. The morphological characteristics were assessed and the enhancement patterns were classified into five categories. After multivariate logistic analysis, the lesion margin and enhancement patterns were significantly different between benign and malignant lesions. The combination of ill-defined margin and hypovascular enhancement for suggesting malignant lesions had a good specificity (94.9%) and accuracy (89.9%). Morphological and enhancement characteristics on CT/MRI may be valuable in differentiating malignant from benign focal splenic lesions.