MR线性扫描扩散加权技术在猪股骨头骨骺缺血模型中的初步应用研究

目的 采用MR线性扫描扩散加权成像(LSDWI)技术,观察乳猪股骨头骨骺缺血不同时期的DWI表现特征及变化过程,以期提供骨骺缺血性损害的时间及程度信息.方法 25只1周龄大小的乳猪,手术结扎一侧股骨颈处全部供血动脉,引起股骨头骨骺缺血,另一侧作为健康对照侧.分别在术前(25只)及术后3 h(25只)、72 h(20只)、1周(15只)、3周(10只)、6周(5只)进行LSDWI,计算股骨头骨骺表观扩散系数(ADC)值,采用配对t检验比较缺血侧和对照侧ADC值的差异,观察不同时期ADC值的变化.各时间点LSDWI扫描完成后分别处死5只,行解剖学及组织学研究.结果 术后3 h,缺血性股骨头的ADC值[(1.22±0.37)×10-3mm2/s]较正常对照侧[(1.73±0.33)×10-3mm2/s]显著下降(t=3.914,P＜0.01),术后72 h ADC值[(2.15±0.32)×10-3mm2/s]较正常对照侧[(1.70±0.22)×10-3mm2/s]升高(t=3.348,P＜0.01),其后一直保持上升趋势至术后第6周[缺血侧为(1.61±0.27)×10-2mm2/s,对照侧为(1.11±0.45)×10-3mm2/s](t=4.136,P＜0.01).除术后第3周和第6周2个时间点ADC值的变化百分之间差异无统计学意义外(t=2.29,P＞0.05),在整个实验过程中,每2个连续时间点之间ADC值的变化百分差异均有统计学意义(P值均＜0.01).组织学研究显示,在缺血性股骨头骨骺,首先是软骨细胞和骨细胞死亡,血管塌陷.随时间的变化,出现不同程度的缺血性股骨头骨骺软骨的异常增厚、二次骨化中心内出现软骨岛和局限性的生长板组织结构破坏.结论 股骨头骨骺的LSDWI表现特征随缺血时间的延长而变化,通过LSDWI技术能获得股骨头骨骺的ADC值,其作为股骨头缺血和坏死的一个指标,可用于评估缺血性骨骺组织受损时间性信息及程度.     

Effect of Arterial Deprivation on Growing Femoral Epiphysis: Quantitative Magnetic Resonance Imaging Using a Piglet Model

Objective

To investigate the usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion MRI for the evaluation of femoral head ischemia.

Materials and Methods

Unilateral femoral head ischemia was induced by selective embolization of the medial circumflex femoral artery in 10 piglets. All MRIs were performed immediately (1 hour) and after embolization (1, 2, and 4 weeks). Apparent diffusion coefficients (ADCs) were calculated for the femoral head. The estimated pharmacokinetic parameters (Kep and Ve from two-compartment model) and semi-quantitative parameters including peak enhancement, time-to-peak (TTP), and contrast washout were evaluated.

Results

The epiphyseal ADC values of the ischemic hip decreased immediately (1 hour) after embolization. However, they increased rapidly at 1 week after embolization and remained elevated until 4 weeks after embolization. Perfusion MRI of ischemic hips showed decreased epiphyseal perfusion with decreased Kep immediately after embolization. Signal intensity-time curves showed delayed TTP with limited contrast washout immediately post-embolization. At 1-2 weeks after embolization, spontaneous reperfusion was observed in ischemic epiphyses. The change of ADC (p = 0.043) and Kep (p = 0.043) were significantly different between immediate (1 hour) after embolization and 1 week post-embolization.

Conclusion

Diffusion MRI and pharmacokinetic model obtained from the DCE-MRI are useful in depicting early changes of perfusion and tissue damage using the model of femoral head ischemia in skeletally immature piglets.     

Early ischemia in growing piglet skeleton: MR diffusion and perfusion imaging

PURPOSE: To determine whether diffusion changes with ischemia of increasing duration, whether diffusion magnetic resonance (MR) imaging provides different information than does gadolinium-enhanced imaging, and which structural and/or biochemical changes are potentially responsible for any changes in diffusion. MATERIALS AND METHODS: Ischemia was surgically induced in one hip of each piglet (n=8) after approval from the Subcommittee on Research Animal Care; the other hip served as a control. Piglets were imaged at approximately 48 hours and 1, 2, 4, and 8 weeks after surgery at 1.5 T by using line-scan diffusion and dynamic gadolinium-enhanced MR imaging. Apparent diffusion coefficients (ADCs) and enhancement ratios (ERs) were calculated. Significant differences in ADC and ER values over time were evaluated by using the Student t test (P<.05). At 8 weeks, piglets were sacrificed for histologic evaluation. RESULTS: MR images of ischemic hips showed essentially no flow 48 hours after surgery. Spontaneous partial reperfusion was observed 1-4 weeks after surgery (ischemic ER/control ER=66%+/-35 [standard deviation]), and the ER of the ischemic hips was well above that of the control hips at 8 weeks. The ADC of ischemic hips was elevated above that of control hips before reperfusion 1 week after surgery by 47%+/-12 and remained elevated despite flow restoration. Gross structural abnormalities on MR images appeared to coincide with reperfusion. Histologic findings revealed abnormal epiphyseal cartilage thickening, cartilaginous islands within ossified tissue, and less fatty marrow in ischemic hips than in control hips; all of these factors could explain elevated ADC. CONCLUSION: Diffusion is sensitive to early ischemia and follows a different time course than that of changes observed with gadolinium enhancement. ADC remained elevated in this model of severe, prolonged ischemia despite the spontaneous partial restoration of blood flow seen on gadolinium-enhanced images.     

Normal and ischemic epiphysis of the femur: diffusion MR imaging study in piglets

PURPOSE: To evaluate normal diffusion characteristics in the femur in piglets and changes in diffusion with increasing duration of femoral head ischemia. MATERIALS AND METHODS: Normal epiphyses, physes, and metaphyses of piglets were evaluated with line-scan diffusion imaging (n = 12) and diffusion-tensor imaging (n = 4). Apparent diffusion coefficient (ADC) differences between normal proximal and distal femoral structures, epiphyseal and physeal cartilage, and epiphyseal and metaphyseal marrow were compared (Mann-Whitney test). Short-term femoral ischemia was investigated after maximal abduction of the hips for 3 hours (n = 6); ADCs before and after abduction were compared (Wilcoxon signed rank test). Prolonged ischemia was investigated with placement of a ligature around the neck of a femur (n = 7); the ADC of the femur in this condition was compared (Wilcoxon signed rank test) with that of the normal contralateral femur. Changes in ADC ratios at three durations of ischemia (Kruskal-Wallis test) were compared. RESULTS: ADC was greater in epiphyseal cartilage (mean +/- 1 SD, 1.62 x 10(-3) mm2/sec +/- 0.38) than it was in physeal cartilage (1.28 x 10(-3) mm2/sec +/- 0.31) (P <.007) and greater in epiphyseal marrow (1.26 x 10(-3) mm2/sec +/- 0.38) than it was in metaphyseal marrow (0.91 x 10(-3) mm2/sec +/- 0.35) (P <.001). There was columnar arrangement of tensors in the physis. ADC decreased 26% after 3 hours of maximal abduction. After femoral neck ligature, ADC increased a mean of 27% after 6 hours and a mean of 75% after 96 hours. CONCLUSION: Normal line-scan diffusion imaging findings indicate relative restriction of diffusion in the metaphysis and parallel orientation of tensors in the physis. Diffusion is initially restricted with decreased blood flow but increases if ischemia lasts longer.     

特发性股骨头缺血性坏死髓腔静脉造影的X线表现

目的探讨特发性股骨头缺血性坏死髓腔静脉造影的诊断价值。材料与方法对１８个ＩＮＦＨ病人的３５个髋４个正常人的髋进行髓腔静脉造影。结果２５个髋有异常改变并经病理证实,有意义的征象是：①２条以上主要静脉不显影;②造影剂向骨干方向返流;③多条静脉明显变细;④造影剂在干骺端滞留。其中前两项是可靠的诊断依据。结论髓腔静脉造影是一种安全而敏感的诊断技术。     

DE MRI观察髋关节自然和外展体位股骨头骨骺血供特征

目的：运用动态钆增强MR成像技术,评价正常股骨头骨骺及髋关节外展固定体位时股骨头骨骺的不同解剖区域的血供特征。方法：此研究包括13例2周龄乳猪。正常骨骺组6例,双髋关节取自然体位行MR扫描;外展固定组7例,双髋关节取极度外展固定体位2h,行MR扫描。主要MR扫描序列为钆增强动态MR成像,运用时间分辨力为3s的SPGR技术,在静脉注射钆之前、注射过程中及之后连续扫描,全部成像时间约4～5min。计算在不同体位动态钆增强MRI图像上股骨头骨骺各个解剖区域在不同时间的增强率,并与相应组织学发现作时照研究。结果：在自然体位组,海绵状骨松质的增强率最高（P〈0．001）,生长板与海绵状骨松质强化快慢之间差异无显著性意义。在外展固定组,生长板的强化速度较海绵状骨松质慢（（P〈0．05）,生长板和骨骺软骨的增强率均较自然体位时明显减低（P〈0．05）。结论：动态钆增强MRI能显示正常以及血供障碍时骨骺不同解剖区域的血液灌注特征。     

Diffusion-weighted MR study of femoral head avascular necrosis in severe acute respiratory syndrome patients

PURPOSE: To evaluate the apparent diffusion coefficient (ADC) of femoral head avascular necrosis (AVN) in severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: Seventy-nine SARS patients with hip pain underwent both conventional and diffusion-weighted MRI (b-value=0-1000 seconds/mm(2)). The abnormal regions on the diffusion-weighted images were outlined by using the conventional images as guides, and the ADCs were calculated. The ADC differences between normal and AVN femoral heads were compared. RESULTS: Of the 158 hips examined, 28 had AVN (11 with bilateral hip AVN, three with right hip AVN, and three with left hip AVN). The mean ADC was markedly greater in the AVN femoral head (1.66 x 10(-3) mm(2)/second+/-0.20) than in the normal femoral head (0.47 x 10(-3) mm(2)/second+/-0.082; P<0.0001). There was no overlap between the normal and AVN femoral heads. CONCLUSION: DWI can provide valuable information regarding the diffusion properties of femoral head AVN, and markedly increased diffusion was identified in AVN.     

(13)N-ammonia PET as a measurement of hindlimb perfusion in a mouse model of peripheral artery occlusive disease.

Peripheral arterial occlusive disease (PAOD) is a leading cause of mortality and morbidity in the western world. The development of noninvasive methods for assessment and comparison of the efficacy of novel therapies in animal models is of great importance. METHODS: Hindlimb ischemia was induced in nude mice by ligation and excision of the left femoral artery (n = 5) or the left iliac artery (n = 10). Assessment of limb perfusion was performed by small-animal PET analysis after intravenous injection of (13)N-ammonia between 24 h and 30 d after surgery using the ratio of perfusion between the left limb (ischemic) and the right limb (control). Activity concentration per area unit was calculated in regions of interest placed on 1-mm-thick images for numeric calculations, and the iliac and the femoral models were compared. In addition, histopathologic studies were performed to assess the degree of necrosis (hematoxylin-eosin) and fibrosis (sirius red). Immunohistochemistry analyses for identification of arterioles (alpha-smooth muscle actin) and endothelium-capillaries-(Bandeiraea simplicifolia I [BS-I] lectin) were also performed. RESULTS: Perfusion in both hindlimbs of control animals was similar (median of the left-to-right ratio = 0.99). Twenty-four hours after ischemia, perfusion of the ischemic limb (% mean +/- SD) was 33.3 +/- 10.6 and 22.1 +/- 9.9 in the femoral and iliac models, respectively. Spontaneous recovery of perfusion in the hindlimb that underwent surgery was significantly lower in the iliac model at day +15 (73.2 +/- 15.5 vs. 51.9 +/- 11.3; P < 0.01). Fibrosis increased progressively until day +30, whereas muscle necrosis was maximal at day +7 with a moderate reduction by day +30. In accordance with this positive effect, there was a statistically significant increase in the area covered with smooth muscle-coated vessels (arterioles) at day +30 in comparison with day 7 (P < 0.05). In addition, a correlation between (13)N-ammonia uptake and the amount of necrosis (r = -0.73; P = 0.06) and fibrosis (r = -0.67; P = 0.05) at day +30 was found. CONCLUSION: (13)N-Ammonia imaging allows semiquantitative evaluation of hindlimb perfusion in surgical mouse models of acute hindlimb ischemia. Although spontaneous perfusion recovery is observed in both models, the iliac model shows a substantially lower recovery and is hence better suited for assessment of new therapeutic strategies for acute hindlimb ischemic disease.     

导向器镜下精准钻孔减压联合冲击波治疗创伤性股骨头坏死的有效性

 目的 探讨精准微创治疗部队官兵创伤性股骨头坏死(avascular necrosis of femoral head, ANFH)的有效性并进行相关分析。方法 选取2014-02至2018-04解放军总医院第三医学中心骨科收治的共77例(93髋)ANFH患者,均为部队官兵。随机分为单纯体外冲击波(extracorporeal shock wave therapy,ESWT)治疗组(对照组)46髋,导向器镜下精准钻孔减压联合ESWT治疗组(联合治疗组)47髋,两组患者分别于治疗前、治疗后的3、6个月及最终随访时采用视觉模拟VAS评分和Harris髋关节评分进行主观疼痛和髋关节功能评估,并对两组股骨头塌陷及生存时间情况应用Kaplan-Meier生存曲线分析比记录。结果 平均随访时间为72个月,两组治疗前髋关节主观疼痛及功能评价比较无统计学意义,治疗后3、6个月及末次随访的髋关节主观疼痛及功能比较,联合治疗组明显优于对照组,差异有统计学意义(P<0.05),且联合治疗组优良率(85.11％)、股骨头塌陷及生存时间明显优于对照组,差异有统计学意义(χ²=6.948, P=0.016)。结论 导向器镜下精准钻孔减压联合ESWT较单纯ESWT治疗,对部队官兵ARCO Ⅰ-ⅢA期ANFH髋关节功能和延缓股骨头塌陷疗效更为满意。     

髂总动脉造影在股骨头坏死介入治疗中的应用价值

目的探讨髂总动脉造影对股骨头缺血性坏死介入治疗的指导意义和应用价值。方法收集182例(216髋)患者,行选择性髂总动脉造影,根据影像确定股骨头供血动脉,行超选择性插管并经导管进行局部药物治疗,记录相关资料。结果全部髂总动脉造影显示清晰,股骨头以旋股内、臀下动脉、旋股外和闭孔动脉为优势供血动脉的分别为192髋、13髋、8髋、3髋,各占88.9%、6.0%、3.7%、1.4%。旋股内动脉发自股深动脉186髋,占86.1%;直接发自股动脉23髋,占10.6%;其他异位起源5髋,占2.3%;缺如2髋,占1.0%。旋股外动脉发自股深动脉211髋,占97.7%;起源于股动脉5髋,占2.3%。介入治疗总曝光时间一般不超过2 m in。结论髂总动脉造影有利于提高股骨头坏死介入治疗的效率、减轻血管损伤和辐射危害。     

DSA在介入治疗股骨头缺血性坏死中的应用

目的：评价ＤＳＡ对介入治疗股骨头缺血性坏死的应用价值。材料和方法：分析１８例介入治疗股骨头缺血性坏死治疗前后股外、内旋动脉数字减影血管造影表现及造影技术有关问题，着重介绍了介入治疗股骨头缺血性坏死的新方法。结果：本组资料经介入治疗后患侧血管ＤＳＡ较治疗前明显改变者占６１．１％，可见股外、内旋动脉分支增多、增粗、头上、下支明显延长至股骨头区，明显改善了血供情况，无明显并发症。术后临床症状、体征改善成正比。结论：介入治疗股骨头缺血性坏死可明显改善血液供应，减轻疼痛症状，是一种安全、简便、有效的治疗股骨头缺血性坏死的新方法，值得推广应用。     

Selective arteriography in fractures of the femur head

The choice between conservative and radical operation in case of femoral neck fractures is very important because it is the determining factor for a successful therapy. In case of epiphysial necrosis, an endoprosthesis as well as an osteosynthesis will be carried out. Selective arteriography of the medial circumflex artery represents the most reliable study to establish, immediately after the fracture, the possible presence of a post-traumatic ischemic necrosis. Angiography, as a reliable diagnostic tool, has to be carried out in the most selective way and needs the image subtraction technique. The authors report their preliminary results on the reliability of angiography in the femoral epiphyseal ischemic necrosis diagnosed by comparing the results of angiography with the Wood light test carried out on the surgically removed femoral head.     

股骨头骨骺缺血性坏死159例临床X线分析

本文分析159例股骨头骨骺缺血坏死，男136例，女23例，主要症状为跛行和髋关节疼痛，早期X线表现为骨骺变小，边缘不规则，密度增高，继而骨骺外上缘扁平，碎裂，骺板模糊不规整，髋关节间隙内侧增宽，股骨颈增粗以及干骺端囊变，后者的形成原因是因局部坏死及因压力而致的细微骨折和出血，结合29例2月至12年随访观察，讨论了其生物力学的变化，认为股骨头扭矩力增大是髋脱位的主要原因，骨骺塌陷变扁，断裂和畸形是由于超负荷的机械力压迫，骨骺内侧1／4是其受力的焦点。     

Dynamic gadolinium-enhanced MRI evaluation of porcine femoral head ischemia and reperfusion

OBJECTIVE: To examine the potential of gadolinium (Gd)-enhanced dynamic MRI in the detection of early femoral head ischemia. Furthermore, to apply a three-compartment model to achieve a clinically applicable MR index for femoral head perfusion during the steady state and arterial hip joint tamponade. DESIGN AND MATERIALS: In a porcine model femoral head perfusion was measured by radioactive tracer microspheres and by using a dynamic Gd-enhanced MRI protocol. Femoral head perfusion measurements and MRI tests were performed unilaterally before, during and after the experimentally induced ischemia of one of the hip joints. Ischemia was induced by increasing intra-articular pressure to 250 mmHg. RESULTS: All pigs showed ischemia of the femoral head epiphysis under hip joint tamponade followed by reperfusion to the same level as before joint tamponade. In two cases perfusion after removal of tamponade continued to be low. In dynamic MRI measurements increases in signal intensity were seen after intravenous infusion of Gd-DTPA, followed by a slow decrease in signal intensity. The signal-intensity curve during femoral head ischemia had a minor increase. Also the coefficient determined was a helpful indicator of femoral head ischemia. CONCLUSIONS: Femoral head blood flow as measured by microspheres fell significantly under joint tamponade. Early detection of this disturbed regional blood flow was possible using a dynamic MRI procedure. A biomathematical model resulted from the evaluation of the intervals of signal intensity over time which allows detection of bone blood flow changes at a very early stage. Using this new method earlier detection of femoral head necrosis may be possible.     

人工关节置换治疗晚期股骨头缺血性坏死合并严重股骨颈前倾角畸形

目的 探讨晚期股骨头缺血性坏死合并严重股骨颈前倾角畸形患者采用普通假体髋关节置换的手术方法及临床疗效.方法 本组男9例,女6例;年龄30～42岁,平均37岁.前倾角40°～50°,术前Harris评分(59±8)分,术中通过将股骨假体缩小前倾角20°～30°,同时将髋臼杯前倾角增大10°～15°,使其基本恢复正常对合关系,防止关节前脱位.术后定期影像学检查和临床疗效Harris髋评分.结果 术后15例患者均获得随访2.5～3.7年(平均2.9年),关节假体稳定性良好,关节活动度基本正常.术后2年Harris评分为(88±6)分,与术前相比,疗效显著(P<0.01).结论 晚期股骨头缺血性坏死合并严重股骨颈前倾角畸形患者手术中通过对普通的股骨假体及髋臼杯安放的角度的联合调整,使关节置换术后人工假体与髋臼的对合基本恢复正常,疗效显著,同时避免了使用小柄股骨假体、转子下截骨或使用特殊前倾角股骨假体等治疗方法.     

SARS和肾移植患者大剂量应用激素后发生缺血性股骨头坏死的比较

目的对SARS和同种异体肾移植术（下称肾移植）两组患者接受糖皮质激素治疗后缺血性股骨头坏死的发生率进行比较,并分析其差异原因,探讨糖皮质激素及其他因素在缺血性股骨头坏死发生中的作用。方法对67例SARS和59例肾移植术后患者的资料进行回顾性分析,主要包括：双侧髋关节MRI、激素用药情况（累积剂量、单次最大剂量和用药时间）、体重、负重指数、最低动脉血氧分压和辅助通气情况。结果缺血性股骨头坏死发生率SARS组为23．9％（16／67）,肾移植组为6．8％（4／59）,两组比较差异显著（P〈0．05）;两组间静脉注射甲泼尼龙累积剂量无显著性差异（P〉0．05）,肾移植组口服泼尼松累积剂量、甲泼尼龙单次最大剂量、激素用药时间及最低动脉血氧分压均大于SARS组（P〈0．01）。结论静脉大剂量使用激素是SARS和肾移植术后发生缺血性股骨头坏死的基础因素之一,急性期缺氧、病毒侵犯和免疫反应等其他因素可能与缺血性股骨头坏死发病有关。     

体外冲击波和髓芯减压术治疗早期股骨头坏死远期临床疗效的比较研究

目的比较体外冲击波和髓芯减压术治疗创伤等导致的早期股骨头坏死的远期临床疗效。方法选取2006年1月~2009年1月收治的132例早期股骨头坏死患者,按治疗方法不同分为体外冲击波治疗组和髓芯减压术治疗组,其中体外冲击波治疗组69例(79髋),髓芯减压术治疗组63例(82髋)。观察和比较两组患者的临床疗效,记录治疗前、治疗后3个月以及末次随访的VAS评分,利用髋关节Harris评分对患者进行髋关节功能评价,记录股骨头生存时间。结果所有患者均获得80~113个月随访,平均96个月。两组患者的年龄、随访时间及治疗前VAS评分与Harris评分比较差异无统计学意义(P0.05)。体外冲击波治疗组患者治疗后3个月和末次随访的VAS评分均显著优于髓芯减压术治疗组(P0.05);体外冲击波治疗组患者术后3个月和末次随访的Harris评分均显著高于髓芯减压术治疗组(P0.05);体外冲击波治疗组的总优良率为82.28%,显著高于髓芯减压术治疗组60.98%(P0.05);体外冲击波治疗组患者股骨头平均生存时间显著长于髓芯减压术治疗组(P0.05)。结论体外冲击波和髓芯减压术治疗创伤等导致的早期股骨头坏死均能取得一定的远期临床疗效。体外冲击波能更好地改善患者的髋关节功能,对早期股骨头坏死的临床疗效优于髓芯减压术疗法。     

MRI of joint fluid in the normal and ischemic hip

MR images in 36 hips with documented avascular necrosis and 80 hips without evidence of joint disease were studied to determine the amount and appearance of fluid in the joint. All MRI examinations were done on a 1.5-T machine and included coronal images made with relative T2 weighting (repetition times = 2000-2500 msec, echo delays = 60-100 msec). The amount of joint fluid, which had an intense signal higher than fat, was graded from 0 to 3 and analyzed with respect to the patient's age and radiographic stage of avascular necrosis. Joint fluid was seen in 84% of presumed normal hips. Only four (5%) of 80 had enough fluid to surround the femoral neck (grade 2), and none had sufficient fluid to distend the joint capsule (grade 3). In comparison, 21 (58%) of 36 hips with avascular necrosis had grade-2 or grade-3 effusions (p less than 0.005), and some fluid was seen in all. Grade-3 effusions were seen in seven (50%) of 14 hips with flattening of the femoral head, compared with only one (5%) of 20 in which the femoral contour was normal. It is concluded that small amounts of fluid are present in both normal hips and those with avascular necrosis. In avascular necrosis, increased joint fluid may be present before radiographic abnormalities occur, but it is greatest after there is flattening of the femoral head. MRI is a highly sensitive method for detecting fluid in the hip joint.     

Soft-tissue tumors evaluated by line-scan diffusion-weighted imaging: influence of myxoid matrix on the apparent diffusion coefficient

PURPOSE: To compare the apparent diffusion coefficients (ADCs) of myxoid and nonmyxoid soft-tissue tumors using line-scan diffusion-weighted imaging (LSDWI), and to investigate the myxoid matrix influence on ADCs of soft-tissue tumors. MATERIALS AND METHODS: This study enrolled 44 patients with soft tissue tumors. They were divided into two groups: one with myxoid-containing soft-tissue tumors (N = 23) and the other with nonmyxoid soft-tissue tumors (N = 21). The 44 patients were also classified histologically into 26 with malignant soft-tissue tumors and 18 with benign soft-tissue tumors. LSDWI was performed using b values of 5 and 1000 second/mm(2). The ADCs of the tumors were calculated and compared for myxoid and nonmyxoid tumors and for benign and malignant tumors. RESULTS: The ADC (mean +/- SD) was 1.92 +/- 0.41 x 10(-3) mm(2)/second in myxoid containing tumors, whereas the ADC was 0.97 +/- 0.33 x 10(-3) mm(2)/second in nonmyxoid tumors. The ADCs of the myxoid and nonmyxoid tumors were significantly different (P < 0.01). The ADCs were 1.45 +/- 0.59 x 10(-3) mm(2)/second in malignant tumors and 1.50 +/- 0.64 x 10(-3) mm(2)/second in benign tumors. The ADCs of benign and malignant soft-tissue tumors were not significantly different. CONCLUSION: The ADCs of myxoid-containing soft-tissue tumors were significantly higher than those of nonmyxoid soft-tissue tumors. The myxoid matrix influences ADCs of both benign and malignant soft-tissue tumors.     

股骨头无血坏死的CT诊断及其与X线平片的关系

虽然对股骨头无血坏死的诊断CT不如MRI灵敏,但可与闪烁摄影媲美。我们对20例正常人(共27髋)进行了股骨头CT扫描作为对照,报告了13例(共15髋)股骨头无血坏死的CT所见并与X线平片分期进行了对照.正常股骨头内可见清晰的星芒征,在较低平面于股骨头内侧可见类似双环之现象。股骨头无血坏死时股骨头内星芒征分支融合成丛成簇,可有囊性变及股骨头骨折变形。CT发现骨折的灵敏度比平片高,因此可以提高疾病分期级别,有助于治疗方案的选择。