应力负荷下兔肩袖急性断裂重建后腱-骨修复动物模型建立及其修复过程中影像学评价

背景：目前尚无公认的动物模型可以作为应力负荷下肩袖损伤的相关研究标准的实验动物模型。目的：建立应力负荷下兔肩袖腱-骨急性断裂重建术后修复动物模型,并对其修复过程中进行影像学评价。方法：将新西兰白兔进行双侧肩关节行冈上肌腱离断术,并行冈上肌腱止点重建,术后随机分为应力负荷组与非应力负荷组。非应力负荷组正常笼养;应力负荷组于冈上肌腱重建术后第2周开始进行肩关节被动屈伸训练。分别于术后第2,4,8周训练结束后行肩关节MRI和超声检查。结果与结论：MRI检查结果显示：术后4和8周,T2WI相应力负荷组连接肌腱与骨组织低信号显示面积较非应力负荷组大。超声检查结果显示：术后4和8周,兔冈上肌腱止点重建处连续性回声,应力负荷组较非应力负荷组稍明显。结果提示,应力负荷下兔肩袖急性断裂术后腱-骨修复动物模型建立相对成功,一定的应力刺激能够促进肩袖腱-骨修复。     

声触诊组织量化成像评估急性闭合性不完全断裂跟腱弹性

目的 探讨声触诊组织量化成像（VTIQ）技术评价中青年男性急性闭合性不完全跟腱断裂开放性修复术前及术后跟腱弹性特征的价值。方法 选取32例中青年男性急性闭合性不完全跟腱断裂患者,采用VTIQ获得双侧跟腱速度模式图,于中立位测量跟腱远段（跟腱跟骨附着处以上5 cm）、中段（跟腱跟骨附着处以上>5~10 cm）及近段（跟腱跟骨附着处以上>10 cm至肌-腱结合处）SWV值,比较术前1周、术后12周和24周两侧跟腱对应节段SWV值。结果 术前1周患侧跟腱SWV值均低于健侧对应节段（P均<0.001）,且双侧跟腱远段SWV值均高于同侧中段及近段（P均<0.01）;术后12周患侧跟腱中段及远段较健侧对应节段SWV降低（P均<0.001）;术后24周患侧跟腱远段较健侧远段SWV值降低（P<0.001）。患侧跟腱各段SWV值随时间延长而逐渐增高,两两时间点比较差异有统计学意义（P均<0.01）。结论 VTIQ可量化评价急性闭合性不完全跟腱断裂术前及术后跟腱弹性;术后可采用VTIQ为跟腱各节段弹性提供客观评估指标。     

The bursal and articular sides of the supraspinatus tendon have a different compressive stiffness

OBJECTIVE: To measure the compressive stiffness of the supraspinatus tendon and to determine whether regional difference exists in the bursal and articular side of the tendon. DESIGN: Indentation testing was performed on both the bursal and articular sides of the supraspinatus tendon, focused on the 'critical area', where rotator cuff tears often occur. BACKGROUND: When the supraspinatus tendon wraps around the humeral head or is under impingement condition, compressive force on the tendon surface is expected. Therefore, compressive stress has been recently considered to be one of the important factors associated with the cuff tear. The mechanical properties would be essential for analytic modeling of stress distribution. METHODS: Indentation tests were performed at 15 locations on the bursal and articular surfaces of the supraspinatus tendon. A mathematical model with exponential relationship was used to describe the measured force-deformation relationship and to calculate the compressive stiffness of the supraspinatus tendon. RESULTS: The over-all initial stiffness on the bursal and articular sides of the tendon was significantly different. On the bursal side, the anterior third had a significantly higher initial stiffness than the other thirds on average. On the articular side, initial stiffness at location 10 mm proximal to the greater tuberosity was significantly higher than the rest on average. CONCLUSIONS: The compressive stiffness of the supraspinatus tendon was found to be non-homogenous throughout the structure.RelevanceNon-homogenous compressive stiffness of the supraspinatus tendon would affect the load transmission within the tendon, which might be associated with the potential mechanism of tear. Such characteristics needs to be considered when performing finite element modeling of stress fields in the tendon.     

实时超声检查与磁共振成像诊断冈上肌腱撕裂的对比研究

目的评价实时超声检查与磁共振成像(MRI)对冈上肌腱撕裂病变的诊断价值。方法回顾性分析2003年1月至2008年1月间经手术证实冈上肌腱撕裂且临床资料完整的70例患者的实时超声检查及MRI检查资料,以开放手术或肩关节镜术中结果作为金标准,比较两种检查方法的有效性。结果 70例冈上肌腱撕裂,术前实时超声检查诊断65例,MRI诊断67例。实时超声检查诊断冈上肌腱撕裂的敏感性、特异性、阳性预测值、阴性预测值及准确性分别为92.8%、82.1%、92.8%、82.1%及89.8%。MRI诊断冈上肌腱撕裂的敏感性、特异性、阳性预测值、阴性预测值及准确性分别为95.7%、85.7%、94.4%、88.9%及92.9%。经χ2检验,冈上肌腱撕裂实时超声检查的有效性与MRI检查的有效性无统计学差异(χ2=0.09,P0.05)。结论实时超声检查与MRI同样能够准确地诊断冈上肌腱撕裂,可作为冈上肌腱检查的首选影像学方法 。     

Visualizing Tendon Elasticity in an ex Vivo Partial Tear Model

Supersonic shear imaging (SSI) is evaluated as a means of visualizing changes in regional tendon elasticity caused by partial tears in a porcine model. Thirty digital flexor tendons were cut to 25% (n = 10), 50% (n = 10) and 75% (n = 10) of the tendon thickness along the deep surface. Tendon elasticity was mapped left of, centered on and right of the tear site before and after tearing from 0% to 2% strain. Shear wave speed increased at 1% (p < 0.05) and 2% (p < 0.001) strain for all regions. Deep surface shear wave speed decreased in the 25%, 50% and 75% tears (p < 0.05 and p < 0.001). Computational tendon tear models were also created to investigate regional changes in strain resulting from a tear. In the computational models, strain on the deep surface decreased progressively with increasing tear size. Visualization of tendon shear wave speed was achieved in normal and partially torn tendons, indicating the potential of SSI to add tendon shear wave speed to traditional morphologic assessment of partial tears, which may improve assessment of tendon health.     

Mechanical effects of immobilization on the Achilles' tendon

OBJECTIVE: To measure the biomechanical effects of immobilization on the Achilles' tendon. DESIGN: Experimental, controlled study. SETTING: Physiatry research laboratory. ANIMALS: Twenty adult rabbits. INTERVENTION: One hindlimb immobilized in a cast for 4 weeks (n=10) or 8 weeks (n=10). The contralateral legs (n=20) served as controls. MAIN OUTCOME MEASURES: Cross-sectional Achilles' tendon area, mode of failure, mean failure load, and tendon stiffness. RESULTS: The Achilles' tendon cross-sectional area did not change. Achilles' tendon-calcaneus units failed at insertion at 4 weeks and in controls. Calcaneus fracture was the most prevalent mode of failure at 8 weeks. The mean load to failure of both immobilized groups (4wk: 187.5+/-45.7N; 8wk: 162.6+/-39.3N) was significantly smaller than that of the control group (549.2+/-93.7N, both P<.005). The mean tendon stiffness of both immobilized groups (4wk: 64.6+/-24.8N/mm; 8wk: 53.9+/-19.9N/mm) was significantly lower than that of the control group (125.1+/-26.5N/mm, both P<.005). CONCLUSIONS: Immobility for up to 8 weeks caused decreased stiffness but no atrophy or rupture of the Achilles' tendon, suggesting that immobility does not constitute a risk factor for Achilles' tendon midsubstance rupture. Clinically, graded reloading is required after immobilization to restore the tendon insertion and to reverse calcaneal disuse osteoporosis.     

US appearance of partial-thickness supraspinatus tendon tears: Application of the string theory. Pictorial essay

The supraspinatus tendon is composed of 5 different layers consisting of intertwining bundles. On a front portion of the tendon, the layers become coated bundles which insert on the trochanter. At the insertion, the superficial or bursal surface of the tendon corresponding to the tendon fibers in contact with the subacromial bursa can be distinguished from the deep surface corresponding to the fibers in contact with the glenohumeral joint. A tendon tear may involve partial or total disruption of the tendon fibers and is called full-thickness tear if it affects the entire tendon, and partial-thickness tear if it involves only part of the tendon. Partial-thickness tears of the supraspinatus tendon include lesions of the superficial, deep and central surface or tendon delamination.A contrast enhanced examination requires injection of contrast agent into the joint (arthrography followed by computed tomography (CT) or magnetic resonance imaging (MRI)) to study the deep surface, and injection into the subacromial bursa (bursography followed by CT) to study the superficial surface. MRI and ultrasound (US) examination allow the study of these different tendon layers without the use of contrast agent (which is not possible at CT).     

玻璃化法保存同种异体肌腱移植材料的可行性

背景:处理同种异体肌腱最主要目的是减少免疫原性和保持肌腱结构与活性。现在临床上常用的低温冷冻法操作复杂、费时,所保存的肌腱活性较低。目的:以玻璃化法保存鸡屈趾深肌腱,探索其作为肌腱移植材料的可行性。方法:将成年来亨鸡跖趾关节远侧屈趾深肌腱切断,以数字表法随机分为2组,分别移植同种异体玻璃化肌腱与自体肌腱。术后2,4,8,12,16周观察移植肌腱在形态结构、羟脯氨酸含量和力学性能等方面的变化。结果与结论:玻璃化肌腱移植组早期存在轻度的免疫排斥反应,但不影响肌腱愈合与重建。两组肌腱周围产生中度粘连,移植后肌腱中段的羟脯氨酸含量先减少,8周后逐渐增高,而吻合口部羟脯氨酸含量随时间逐渐增高,两组间羟脯氨酸含量差异无显著性意义。在8周内玻璃化肌腱移植组吻合口部的破裂强度与弹性模量低于自体肌腱移植组(P<0.05),12周后差别无显著性意义。两组肌腱中段部生物力学性能差异无显著性意义。说明玻璃化保存的同种异体肌腱生物活性好、免疫原性低,是良好的肌腱移植材料。     

超声监测跟腱断裂手术治疗后跟腱周长及断端血流动态变化的价值

目的 探讨超声监测跟腱周长及断端血流在跟腱手术治疗后恢复过程中的意义.方法 对31例跟腱断裂修补术后不同时期的患者,超声动态观察跟腱术后断端的血流变化,用轨迹测量法测量健侧和患侧跟腱多点的周长.结果 跟腱断裂后患侧跟腱周长较健侧大(P＜0.05).术后随着修复时间的延长,患侧跟腱周长有逐渐变小的趋势,但仍较同时期健侧跟腱的周长值大.跟腱术后8周,跟腱断端的血流信号由丰富逐渐减少.结论 监测跟腱术后周长及断端血流的变化可以准确跟踪跟腱术后的动态演变过程.     

玻璃化法保存同种异体肌腱移植材料的可行性

背景：处理同种异体肌腱最主要目的是减少免疫原性和保持肌腱结构与活性。现在临床上常用的低温冷冻法操作复杂、费时,所保存的肌腱活性较低。目的：以玻璃化法保存鸡屈趾深肌腱,探索其作为肌腱移植材料的可行性。方法：将成年来亨鸡跖趾关节远侧屈趾深肌腱切断,以数字表法随机分为2组,分别移植同种异体玻璃化肌腱与自体肌腱。术后2,4,8,12,16周观察移植肌腱在形态结构、羟脯氨酸含量和力学性能等方面的变化。结果与结论：玻璃化肌腱移植组早期存在轻度的免疫排斥反应,但不影响肌腱愈合与重建。两组肌腱周围产生中度粘连,移植后肌腱中段的羟脯氨酸含量先减少,8周后逐渐增高,而吻合口部羟脯氨酸含量随时间逐渐增高,两组间羟脯氨酸含量差异无显著性意义。在8周内玻璃化肌腱移植组吻合口部的破裂强度与弹性模量低于自体肌腱移植组（P〈0.05）,12周后差别无显著性意义。两组肌腱中段部生物力学性能差异无显著性意义。说明玻璃化保存的同种异体肌腱生物活性好、免疫原性低,是良好的肌腱移植材料。     

Healing processes of the glenoid labral lesion in a rabbit model of shoulder dislocation

Traumatic dislocation most commonly occurs at the shoulder joint. After an initial dislocation of the shoulder, the labrum is usually detached from the glenoid (Bankart lesion). If this lesion fails to heal, surgical repair is necessary. The purpose of this study was to determine the histological and biomechanical healing process of a simulated Bankart lesion created in rabbits. A labral injury was surgically created in 40 Japanese White rabbits. The labrum was sharply dissected from the glenoid rim simulating a Bankart lesion, and was repositioned without sutures. The joint capsule, the supraspinatus and infraspinatus tendons, and the deltoid were anatomically repaired with sutures. Eight rabbits each were sacrificed at 1, 2, 3, 4, and 5 weeks after the surgery for histological and biomechanical examinations (4 animals each). The histology and biomechanical properties of the normal capsulolabral structure was examined in 8 control rabbits. Inflammatory cell infiltration into the gap between the glenoid and the labrum was noted from 1 week. The gap was covered with fibrous connective tissue accompanied by the collagen fibers by 3 weeks. The healing process was completed histologically by 3 weeks. Biomechanically, the tensile load, which decreased significantly at 1 week, gradually increased and returned to the level of intact shoulder at 4 weeks. At least four weeks are necessary for the healing of the labral injury in rabbits. Considering the difference between humans and rabbits, it seems reasonable to let the patients go back to sports 2 to 3 months after dislocation or surgical repair.     

Pre- and postoperative evaluation of the metabolic activity in muscles associated with ruptured rotator cuffs by F-FDG PET imaging

We examined uptake of 2-[(18)F]-fluoro-2-deoxy-D-glucose (FDG) using positron emission tomography (PET) into the bilateral shoulder muscles of four patients before and after unilateral rotator cuff repair. The relative ratio of the subtracted standardized uptake value on the supraspinatus with a torn supraspinatus tendon to that of the subscapularis on the ipsilateral side was significantly lower than that on the normal side (0.69 +/- 0.05 versus 1.06 +/- 0.36). The relative ratio of the infraspinatus on the rupture side was also significantly lower than that on the normal side (0.91 +/- 0.09 versus 1.41 +/- 0.35). However, by 6 months postoperative, the reduced glucose metabolism in these muscles had recovered to the same levels as those on the normal side. As indicated by FDG PET, muscle metabolism in rotator cuff tears was reduced, subsequently recovering to the level of the normal side after operative repair.     

Effects of glenohumeral rotations and translations on supraspinatus tendon morphology

OBJECTIVE: The purpose of this study was to evaluate the effects of glenohumeral rotations and humeral head translations on supraspinatus tendon morphology. DESIGN: A convenience sample of cadaver shoulders was used to measure supraspinatus tendon shape and dimensions from MRI images. BACKGROUND: Epidemiological evidence has indicated that shoulder elevation and external rotation may be risk factors for rotator cuff tendon pathology, but little is known about how these postures affect tendon morphology. METHODS: Measurements of supraspinatus tendon morphology were made from three-dimensional reconstructions based on T2-weighted fast spin-echo magnetic resonance images. Seven cadaver arms were imaged at neutral, 45 degrees external and 45 degrees internal rotations at 0 degrees, 30 degrees, and 60 degrees of glenohumeral abduction. Measurements of the anterior, middle, and posterior portions of the tendon were made using ANALYZE software. RESULTS: The supraspinatus tendon was twisted at the muscle-tendon junction of the middle and posterior portions in 45 degrees external and 45 degrees internal axial rotations of the humerus, especially over 30 degrees of abduction. Abduction over 30 degrees shortened the entire supraspinatus tendon. External and internal rotation motions elongated the anterior and posterior portions, respectively. CONCLUSIONS: Arm posture affects morphology of the supraspinatus tendon. RELEVANCE: The results support the epidemiologic evidence linking external rotation and abduction to supraspinatus tendon disorders.     

Measurement of strain and tensile force of the supraspinatus tendon under conditions that simulates low angle isometric elevation of the gleno-humeral joint: Influence of adduction torque and joint positioning

BackgroundRecently, supraspinatus muscle exercise has been reported to treat rotator cuff disease and to recover shoulder function. However, there have been no report on the direct measurement of strain on the supraspinatus tendon during simulated isometric gleno-humeral joint elevation.MethodsTen fresh-frozen shoulder specimens with the rotator cuff complex left intact were used as experimental models. Isometric gleno-humeral joint elevation in a sitting position was reproduced with low angle of step-by-step elevation in the scapular plane and strain was measured on the surface layer of the supraspinatus tendon.FindingsIn isometric conditions, applied tensile force of the supraspinatus tendon increased significantly with increases in adduction torque on the gleno-humeral joint. Significant increases in the strain on the layer were observed by increase in adduction torque, which were recorded in isometric elevation at − 10° and 0°, but little increase in the strain was observed at 10° or greater gleno-humeral elevation.InterpretationIncreased strain on the surface layer of the supraspinatus tendon was observed during isometric gleno-humeral elevation from − 10 to 0°. These findings demonstrate a potential risk of inducing overstretching of the supraspinatus tendon during supraspinatus muscle exercise.     

Effectiveness of tendon transfers for massive rotator cuff tears: a simulation study

OBJECTIVE To determine what the most effective tendon transfer is in the case of a dysfunctional rotator cuff. DESIGN: A tendon transfer procedure of latissimus dorsi, teres major or a combination of these two to the insertions of either teres minor, infraspinatus, supraspinatus, or subscapularis is simulated using a biomechanical musculoskeletal model of the upper extremity. BACKGROUND: Massive rotator cuff tears are not easily repaired. To compensate for this loss of rotator cuff function other techniques like muscle transfers are developed. METHODS: Three range of motion tasks and six activities of daily living of 24 subjects were measured. Kinematics from these tasks were used as input to the Delft Shoulder and Elbow Model. The muscle parameters of the Delft Shoulder and Elbow Model were modified to simulate a rotator cuff tear and the ability to perform the measured tasks with and without simulated transfer procedures was checked. RESULTS: The highest improvements (28-30%, P = 0.00 ) in the ability to perform tasks were observed after a simulated tendon transfer of either both muscles or teres major alone attached to the supraspinatus or infraspinatus insertion. Although all transfer procedures produce significant improvements (P = 0.00 ), there is a significant difference between the procedures (Chi square=58.8, P = 0.00 ) dependent on attachment site. CONCLUSIONS: According to the simulation procedure used in the current study, a tendon transfer of teres major and latissimus dorsi or teres major alone to the supraspinatus insertion appears to be the most effective procedure in the case of a dysfunctional rotator cuff. Practical factors, like subacromial space, volume of the muscles and tendons, tensile properties and the ability to split the muscles, will finally determine which is the preferred transfer option.     

应用碱性成纤维细胞因子与维生素C复合降解膜防止肌腱粘连的实验研究

目的 探讨碱性成纤维细胞因子(bFGF)与维生素C复合降解膜防止肌腱粘连的可行性。方法 60只新西兰大耳白兔随机平均分成实验组和对照组。常规手术制备自体肌腱移植动物模型,实验组肌腱移植处包裹bFGF与维生素C复合降解膜,对照组不包裹。术后第3周常规HE染色和硝酸银染色分别观察2组成纤维细胞核和维生素C的变化,Luzex-F图像分析仪测定胶原纤维数量,术后第8周测定移植腱腱周粘连程度和最大抗拉力值。结果 术后第3周,实验组成纤维细胞核和维生素C银染颗粒明显多于对照组;实验组肌腱内部胶原纤维数量(1230.5±56.4)根,明显多于对照组(998.4±26.2)根,差异有统计学意义(t=11.78,P＜0.001)。术后第8周,实验组腱周粘连程度(Ⅰ级为1根,Ⅱ级7根,Ⅲ级2根,Ⅳ级0根,Ⅴ级0根)明显轻于对照组(Ⅰ级0根,Ⅱ级0根,Ⅲ级1根,Ⅳ级1根,Ⅴ级8根),差异有统计学意义(Z =3.922,P＜0.005),实验组移植腱最大抗拉力值(17.38±1.73)N明显高于对照组(11.65±1.29)N,差异有统计学意义(t=8.39,P＜0.001)。结论 bFGF与维生素C复合降解膜可以促进成纤维细胞增殖和胶原纤维合成,提高肌腱生物力学性能,防止肌腱粘连。     

兔肩袖损伤模型的建立及初步组织学研究

背景:兔的冈上肌形态及结构与人类相仿,在组织学上,兔肩袖肌腱包括与人类相似的由肌腱到骨的移行区域,可用于腱-骨愈合的研究。目的:建立兔的肩袖损伤模型,探讨此模型的可行性并进行肩袖愈合的初步组织学研究。方法:18只骨骼成熟雄性新西兰大耳白兔,建立肩袖损伤模型后随机数字表法均分为2组:修复组造模后1周行腱-骨缝合;对照组不予修复。分别于造模后2,4,8周对冈上肌标本进行切片及苏木精-伊红染色,观察冈上肌的脂肪浸润情况和腱-骨愈合情况。结果与结论:兔冈上肌的解剖结构和组织结构均与人类相似,肩袖损伤模型建立和手术修复的操作过程可重复性高。两组均未观察到明显的冈上肌脂肪浸润和萎缩变性。修复组在8周时形成了新的冈上肌止点,对照组则无新止点形成。说明急性冈上肌损伤修复后8周可形成新止点,兔是建立肩袖损伤模型的合适动物并适用于肩袖疾病的研究。     

Extensibility of the supraspinatus muscle can be predicted by combining shear wave elastography and magnetic resonance imaging-measured quantitative metrics of stiffness and volumetric fat infiltration: A cadaveric study

BackgroundA torn rotator cuff tendon will retract over time causing changes in muscle properties and decreasing its extensibility, or deformation. During surgery, large tensile loads are applied to bring the torn tendon to the footprint. Poor muscle extensibility and large tensile stresses at the repair might lead to gap formation or re-tear of the repair. A quantitative evaluation of muscle properties could be used to predict the extensibility of the supraspinatus (SSP) muscle.MethodMagnetic resonance imaging (MRI)-measured volumetric fat fraction and shear wave elastography (SWE)-measured elastic modulus of the SSP muscle were obtained on seventeen cadaveric shoulders. Experimental extensibility and stiffness were then measured by axially pulling the tendon up-to 60 N. Univariate and multivariate analyses were used to determine the correlation and contribution of fat fraction and elastic modulus to experimental outcomes.FindingsSWE moduli negatively correlated with SSP muscle extensibility (r = 0.54–0.58, P ≤ 0.0259); fat fraction resulted in a positive correlation (r = 0.69, P = 0.0021). SWE measurements, solely, explained up to 34% and 33% of the variability in measured extensibility and stiffness, respectively. Fat Fraction, solely, explained 48% of the variability in extensibility and 36% of the variability in stiffness. These methods combined predicted up to 62% of the musculotendinous extensibility.InterpretationThis study showed a comprehensive quantitative assessment of SSP muscle properties using SWE to estimate stiffness and MRI to measure fatty infiltration. The extensibility of the detached muscle/tendon unit was highly correlated to material properties of the muscle when these methods were used in combination.     

兔膝关节髌骨骨腱接点重接的低场MR扫描和早期表现

目的研究新西兰成年白兔膝关节髌骨骨腱接点重接模型MR扫描方法和表现。方法 20只成年兔左膝髌骨骨腱接点损伤修复分别于术后2周、4周行MR横断、矢状、冠状面扫描,扫描序列包括SET_1WI、GET_1WI、GET_2WI和STIR序列,分析MR表现。结果成年白兔左膝髌骨骨腱接点损伤修复模型术后2周MR可见髌骨骨腱接点重接区域结构模糊,髌韧带下1/4段肿胀;术后4周见髌骨清晰,髌韧带上3/4段轮廓可辨,髌韧带下1/4段水肿减轻,张力良好。结论 MR可显示兔膝关节髌骨骨腱接点重接术后早期变化,可望应用于长期观察髌骨骨腱接点重接修复的影像研究。     

First application of axial speed of sound to follow up injured equine tendons

Ultrasonography is an established technique to follow up injured tendons, although the lesions’ echogenicity tends to become normal before the tendon is ready to sustain the stresses imposed by exercise. Normalized axial speed of sound (SOS) has been found to correlate with an injured tendon’s stiffness; therefore, the purpose of this study was to establish whether SOS would be a useful tool in tendon injury follow-up. Axial SOS was measured in 11 equine superficial digital flexor tendons during a 15-week follow-up period and compared with an ultrasonographic grading system. SOS significantly decreased 2 weeks after the surgical induction of a core lesion, showing a minimum between 7 and 10 weeks; ultrasonographic grade showed a minimum at 3 weeks and increased thereafter. The ultrasonographic grading at 15 weeks was correlated to normalized SOS. These results suggest that axial SOS provides complementary information to ultrasonography that could be of clinical interest.