Magnetic resonance imaging of the ankle: Pathology of the lateral and posterior compartments

Magnetic resonance imaging (MRI) is the gold standard for imaging the tendons and the ligaments of the ankle. MRI combines excellent tissue contrast and accurate anatomic delineation of joint structures. In the first article of this series, we discussed a compartmental approach to the interpretation of ankle pathology focusing on the anterior and medial compartments. This article will complete the MR review of the ankle, with a focus on the lateral and posterior compartments of the ankle.     

Evaluation of thickness and appearance of anterior talofibular and calcaneofibular ligaments in normal versus abnormal ankles with MRI

Injuries to the lateral ligaments of the ankle are common in medical practice. The most commonly injured ligaments are the anterior talofibular (ATFL) and calcaneofibular (CFL) ligaments. When undertaking MRI evaluation of ankle injuries it is important to understand the normal dimensions, appearance and variations of these ligaments. Twenty‐eight consecutive patients referred for MRI of the ankle underwent bilateral scanning. The thickness of normal and abnormal ATFL and CFL was determined. The mean thickness of the ATFL was 2.19 ± 0.6 mm and the CFL measured 2.13 ± 0.5 mm. One normal ankle had an extremely thin ATFL (0.8 mm) with an otherwise normal appearance, whereas two ankles had an ATFL with a high attachment, both of which were deemed to be normal variants. Nineteen per cent of normal CFLs were noted to consist of a lateral hypointense band with a medial isointense medial band. Two variations of normal ATFL, one normal variant CFL and a measurement of the normal thickness of the ATFL and CFL have been presented in this paper. These variations have not been described previously by other authors. It is envisaged that these findings will assist in the MRI assessment of the lateral ankle ligaments.     

不稳定性下胫腓联合损伤的诊治研究进展

Syndesmosis is a kind of fibrous articulation in which the opposing joint surfaces are united by ligaments. The distal tibiofibular syndesmosis consists of a complex of ligaments that provide stability to the joints. The anterior, posterior and transverse tibiofibular ligaments together with the interosseous ligament form the distal tibiofibular syndesmosis. Syndesmosis injuries are rare, but very debilitating and frequently misdiagnosed. It is estimated that 10% of all ankle fractures and 20% of operatively treated ankle fractures are accompanied by syndesmotic injury. Distal tibiofibular syndesmotic ligament injury can also occur in isolation mostly due to an extorsion or in association with damage to the lateral ankle ligaments. Syndesmotic injury leads to subsequent mortise instability and should be treated with syndesmotic stabilization to prevent long-term complications of ankle joint. Immediate reconstruction of the unstable syndesmosis is indicated, because a delay could expedite the development of degenerative arthritis. However, the precise diagnosis of distal tibiofibular syndesmotic ligament injury is critically difficult. The distinction should be made between syndesmotic ligament disruption and real syndesmotic instability. Radiographic measures including tibiofibular overlap, tibiofibular space, medial and superior space are of little value in detecting distal tibiofibular syndesmosis, because all these parameters depend on the rotation of the ankle joint. CT and MRI could also be used in detecting syndesmotic disruption in patients with distal tibiofibular syndesmotic ligament injuries. Intra-operative stress testing is essential in the diagnosis for syndesmotic injuries. Although ankle arthroscopy is a more sensitive method than radiography, it is more invasive and not all surgeons have the expertise to perform ankle arthroscopy. Therefore, there has no“gold standard”diagnostic measure in testing the instability of distal tibiofibular syndesmotic ligament injuries. Furthermore, the need for distal tibiofibular syndesmotic fixation is not fully clear despite the abundance of literature concerning the treatment of ankle fractures and isolated syndesmotic injuries. Fixation using screw is widely preferred in the current concepts of surgical treatment. At present, the following items in treating distal tibiofibular syndesmotic ligament injuries are still in the arguments: location of the screw fixation, number of the screws used in the fixation, 3 or 4 cortex penetrated, diameter of the screw and the foot position. Therefore, the purpose of the present review article is to summarize the evidence about the diagnosis and treatment of instable distal syndesmotic injuries.     

Diagnostic imaging of ankle syndesmosis injuries: A general review

Literature on the various techniques for imaging injuries to the ankle syndesmosis to determine the most appropriate imaging modality for diagnosing syndesmosis ligament disruption and instability was reviewed using the following data sources: Pubmed, Google scholar, SportsDiscus, E‐journals and PLOSone. Search terms used were: syndesmosis paired with injury, imaging, radiology, X‐ray, stress X‐ray, arthrography, ultrasound, nuclear medicine scan, CT scan, MRI and arthroscopy. Articles were selected by reading abstracts and the full article if indicated. Further articles were derived from the references of the primary articles. Plain x‐rays of the ankle will detect approximately half on AP view to two‐thirds on mortise view of syndesmosis injuries. Syndesmosis injuries frequently occur in association with tibial or fibular fractures. Intra‐operative stress radiography failed to detect approximately half of instabilities confirmed at arthroscopy. The current benchmark imaging techniques to diagnose syndesmosis injury and diastasis are arthroscopy and high‐power (3T) MRI. Ultrasound is a promising, developing, cost‐effective imaging technique which is yet to reach its full diagnostic potential. CT and nuclear medicine scans have limited roles. MRI (3T) scanning in the plane of the syndesmotic ligaments is the investigation of choice to detect ankle syndesmosis injuries. In the presence of associated injuries requiring surgery, arthroscopic viewing with stress examination is the diagnostic benchmark when available.     

Magnetic resonance imaging of the ankle: Pathology of the anterior and medial compartments

Magnetic resonance imaging (MRI) is the gold standard for imaging the tendons and the ligaments of the ankle. MRI combines excellent tissue contrast and accurate anatomic delineation of joint structures. In this pictorial essay, the first of two parts, we delineate the ankle into anatomic compartments and use this as a template for describing pathology in each compartment.     

Radiological classification of meniscocapsular tears of the anterolateral portion of the lateral meniscus of the knee

In an arthroscopic–MRI correlation study of acute injuries to the knee it was found that anterolateral meniscocapsular separations of the lateral aspect of the knee were missed on MRI reporting. Eighty sports‐related injuries of the knee were seen by experienced orthopaedic surgeons at the University of Malaya Medical Centre and at the National Sports Centre, Malaysia from January 1996 to July 1997. Fifty of the patients were suspected to have meniscal tears that were either lateral or medial on clinical examination and they were sent for MRI. Many of these patients were tertiary referrals. Magnetic resonance imaging examinations in 27 of the 50 patients were reported as not showing any intrasubstance or obvious meniscocapsular tears, but arthroscopy performed on them revealed anterolateral meniscocapsular tears of the lateral meniscus of varying degrees in nine of these patients. In retrospect the tears could be seen on MRI, and a pattern to the tears was noted and classified as follows. Type 0, normal; type 1, torn inferior or superior meniscocapsular attachment; type 2, both meniscofemoral and meniscotibial ligaments torn but with minimal separation of meniscus and capsule by fluid or synovitis; and type 3, marked separation of meniscus and capsule by fluid (> 3 mm). Ten patients who did not undergo arthroscopy for various personal and financial reasons underwent MRI which showed type 1 and type 2 tears, and were treated conservatively. These patients were all asymptomatic after 4–6 weeks with regard to clinical signs, suggesting a lateral meniscal tear. Magnetic resonance imaging therefore does reveal minor degrees of meniscocapsular tears anterolaterally when one understands the normal anatomy in this region.     

Magnetic resonance imaging of cervical ligamentous anatomy and traumatic ligamentous injuries

Cervical spine trauma accounts for majority of spinal injuries, and approximately one‐third involve the craniocervical junction (CCJ). Due to its high sensitivity, magnetic resonance imaging (MRI) has become the standard tool for imaging suspected ligamentous injuries in an unstable spine and in patients with neurological deficits having a normal CT. The ligamentous anatomy of the CCJ is complex, and thorough knowledge is a prerequisite for accurate interpretation of the MRI findings. This pictorial essay aims to familiarise radiologists with the ligamentous anatomy, mechanisms of injury and MRI appearances of injuries in the cervical spine, with emphasis on the CCJ.     

Computed tomography and magnetic resonance imaging of unusual causes of ankle pain

Computed tomography and MRI are frequently utilized to evaluate ankle pain that remains unexplained by radiography. The most common causes of ankle pain are related to trauma and the imaging appearances of these entities are well established in the radiologic and orthopedic literature. A smaller percentage is comprised of non‐traumatic disorders. Our goal is to emphasize the value of CT and MRI in recognition of these less common and unusual causes of ankle pain.     

前交叉韧带重建术保留残端韧带的方法及意义

目的探讨保留残端韧带进行前交叉韧带重建的方法及意义。方法2005年6月至2011年6月,我院共收治前交叉韧带损伤178例,其中运动伤63例,军事训练伤61例,交通伤54例;部分断裂35例,韧带松弛16例。男119例,女59例,年龄为17～46岁,平均28岁。所有病例经关节镜检查证实,其中前交叉韧带完全断裂127例,部分束支断裂35例,韧带松弛16例。前交叉韧带胫骨定位器定位于原前交叉韧带胫骨附着残迹的中心点偏内、偏后,即外侧半月板前角游离缘的延长线、胫骨内棘前方2mm,关节外定位于胫骨结节内侧2cm,胫骨骨道定位器标定45°方向,钻入导针,根据移植肌腱的直径选择相应的胫骨钻头,沿导针钻孔建立胫骨隧道。膝关节屈曲90°,通过胫骨隧道放置合适股骨隧道定位器,于右膝10～11点左膝1～2点位置打入导针,选择与移植肌腱直径相同的钻头钻取股骨隧道,深度为3cm。前交叉韧带完全断裂者不对胫骨端或股骨端的残端进行清理,移植的肌腱穿过胫骨或股骨残端,残余韧带似套袖样包裹于重建韧带的表面。前交叉韧带单束支损伤者除了保留断裂束支的残端外,对因受损而出现松弛的另一束支也予以保留。对于前交叉韧带明显松弛者,将移植的肌腱穿过松弛韧带胫骨或股骨附着点附近,使移植的肌腱与原韧带重叠或缠绕。股骨端采用Rigidfix固定,胫骨端采用Intrafix固定。术后采用Lysholm膝关节功能评分对手术效果进行评价。结果所有患者术后均随访12～24个月,平均19个月。术后膝关节稳定性增强,Lysholm膝关节功能评分：术前平均（68.6±5.1）分,其中完全断裂组（67.4±6.2）分,部分束支断裂组（71.1±4.6）分,韧带松弛组（72.7±4.1）分;术后平均（94.9±0.9）分,其中完全断裂组（94.6±5.5）分,部分束支断裂组（95.3±3.8）分,韧带松弛组（96.4±4.2）分。术后较术前平均提高26.3分。对手术前后Lysholm膝关节功能评分进行统计学分析,结果有统计学意义（P＝0.0000）。结论保留残端重建前交叉韧带,有助于移植肌腱再血管化、本体感觉的建立和减少关节液渗入骨隧道,有利于维持膝关节的稳定性,从而获得满意的临床疗效。     

Achilles tendon imaging

The Achilles tendon is the largest and strongest tendon in the body, yet one of the most commonly injured. Tendon degeneration is a relatively common disorder, predisposing to tears and often associated with paratenonitis. Numerous other diseases involve the Achilles tendon, some with classic imaging appearances, others with non‐specific appearances. The aim of this pictorial essay is to review the radiographic, computed tomographic, ultrasonographic and MR appearances of the normal and diseased Achilles tendon.     

Magnetic resonance imaging of the supraspinatus tendon: The significance of signal intensity alterations at the‘criticalzone’

A pictorial essay of normal and abnormal appearances of the supraspinatus tendon is presented. An increased signal intensity within the supraspinatus tendon on short TE sequences is not necessarily abnormal. Increased signal seen within the tendon on modern magnetic resonance imaging (MRI) units is often due to a phenomenon known as the‘magic angle’effect. Only when supraspinatus tendon signal intensity is greater than that of muscle on long TE (T2) sequences should it be considered to be abnormal. The physical basis for the magic angle effect is outlined and a pictorial essay demonstrating the practical implications of this effect is presented. A comparison is made to signal intensity changes seen with partial and complete tears of the supraspinatus tendon. Correlation is made with important morphologic features of partial or complete tears.     

Debilitating musculoskeletal pain and stiffness with letrozole and exemestane: associated tenosynovial changes on magnetic resonance imaging

Objective Arthralgia, skeletal and muscle pain have been reported in postmenopausal women under treatment with third generation aromatase inhibitors (AIs). However, the pathogenesis and anatomic correlate of musculoskeletal pains have not been thoroughly evaluated. Moreover, the impact of AI-induced musculoskeletal symptoms on normal daily functioning needs to be further explored. Patients and methods We examined 12 consecutive non-metastatic breast cancer patients who reported severe musculoskeletal pain under a third generation AI; 11 were on letrozole and 1 on exemestane. Clinical rheumatological examination and serum biochemistry were performed. Radiological evaluation of the hand/wrist joints were performed using ultrasound (US) and/or magnetic resonance imaging (MRI). Results The most common reported symptom was severe early morning stiffness and hand/wrist pain causing impaired ability to completely close/stretch the hand/fingers and to perform daily activities and work-related skills. Six patients had to discontinue treatment due to severe symptoms. Trigger finger and carpal tunnel syndrome were the most frequently reported clinical signs. US showed fluid in the tendon sheath surrounding the digital flexor tendons. On MRI, an enhancement and thickening of the tendon sheath was a constant finding in all 12 patients. Conclusions Musculoskeletal pains in breast cancer patients under third generation AIs can be severe, debilitating, and can limit compliance. Characteristic tenosynovial, and in some patients joint changes on US and MRI were observed in this series and have not been reported before.     

Susceptibility weighted imaging: a pictorial review

Susceptibility weighted imaging (SWI) is a valuable technique in the evaluation of a wide variety of intracranial pathologies. SWI is a gradient echo sequence utilising both phase and magnitude data to achieve exquisite sensitivity to tissue magnetic susceptibility effects. Normal SWI appearances and common artefacts are illustrated. Examples of SWI in common intracranial pathologies such as subarachnoid, intraventricular and intraparenchymal haemorrhage, intra-axial and extra-axial tumours, pyogenic and non-pyogenic infections, trauma, neurodegenerative diseases and vascular disease including aneurysms, vascular malformations are illustrated and discussed. This pictorial essay will enable radiologists to recognise the normal, artefactual and common intracranial pathological appearances of SWI.     

A Case of Contiguous Primary Hepatic Marginal Zone B-Cell Lymphoma and Hemangioma Ultimately Diagnosed Using Contrast-Enhanced Ultrasonography

Primary hepatic marginal zone B-cell malignant lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is extremely rare. We present a case in which a lesion was diagnosed as 2 contiguous tumors (MALT lymphoma and hemangioma) using contrast-enhanced ultrasonography (US) with sonazoid. There has been no previous case of contiguous hepatic MALT lymphoma and hemangioma. The present case was a female with no medical history. We detected a snowman-like appearance, which was a tumor of 15 mm in diameter with hypo- and hyper-echogenicities in the lateral and medial parts, respectively, in the Couinaud''s segment (S6) of the liver on US. The tumor appeared as a single lesion with a low-density area in the unenhanced phase and prolonged enhancement in the equilibrium phases on dynamic CT. On MRI, the whole lesion showed a low-intensity signal on T1-weighted imaging, but isointensity in the lateral part and high intensity in the medial part were seen on T2-weighted imaging. On contrast-enhanced US, the lateral hypoechoic region was homogenously hyperenhanced in the early vascular phase, and the contrast medium was washed out after about 30 s; in contrast, the medial hyperechoic region was gradually stained from the margin toward the central region. The tumor showed a defect in both hypo- and hyperechoic regions in the postvascular phase. Hemangioma was suspected for the medial part based on the typical image findings, but the lateral part was not given a diagnosis. Thus, surgical resection was performed. The medial part was a hemangioma, and the lateral part was a MALT lymphoma by histopathological findings.Key Words: Primary hepatic malignant lymphoma, Malignant lymphoma of mucosa-associated lymphoid tissue, Hemangioma, Contrast-enhanced ultrasonography     

侧脑室肿瘤的MRI诊断及鉴别诊断

目的:分析侧脑室肿瘤的MRI影像特点,提高侧脑室肿瘤诊断的准确性。方法:回顾性分析28 例经手术病理证实的侧脑室占位性病变的MRI影像学表现。 结果:大多数侧脑室肿瘤具有年龄和性别特征。如脑膜瘤好发于30~50岁,女性多见;中枢神经细胞瘤发病年龄在20~40岁;转移瘤均大于40岁。不同的侧脑室肿瘤,其好发部位不同。室间孔区好发中枢神经细胞瘤,侧脑室体部好发星形细胞瘤,脑膜瘤和转移瘤好发于侧脑室三角区。不同侧脑室肿瘤的MRI表现有所不同,部分具有特征性表现。脑膜瘤增强后呈明显均匀强化。星形细胞瘤,邻近脑组织受侵伴水肿,增强扫描可见不均匀强化。中枢神经细胞瘤,围绕透明隔生长,周围可见多发囊变,增强可见不均匀强化。少突胶质细胞瘤内可见多发钙化灶。转移瘤,增强扫描大多数可见环形强化。室管膜瘤,增强扫描明显强化,容易侵犯邻近脑实质。结论:MRI影像学表现结合肿瘤的部位、发病年龄、强化程度和磁共振波谱(MRS)表现等可以提高侧脑室肿瘤的术前诊断准确率。     

MRI in greater trochanter pain syndrome

The greater trochanter pain syndrome refers to pain on the lateral aspect of the hip joint. This is frequently attributed to trochanteric bursitis and distension of the subgluteal bursae. Associated tears of the tendons of gluteus medius and minimus have been described and may result from repetitive frictional trauma to these tendons and their associated bursae secondary to impingement beneath the tensor fascia lata. Occasionally tendinous damage may result from acute local direct trauma or a hyperadductive strain injury. We describe MRI in two patients with chronic lateral hip pain.     

Role of CT and MR in detection and staging of pancreatic adenocarcinoma.

In this review article, the roles of imaging with CT and MRI in the detection and staging of pancreatic carcinoma will be discussed. The frequently employed techniques using these modalities, the common imaging appearances of this tumor, and the limitations of imaging will be addressed.     

半月板的MRI测量指标及多元回归结果

目的为明确半月板移植手术前同种异体半月板匹配性测量方法,探索有效的半月板的MRI测量方法。方法选取我院门急诊、住院患者58膝,行MRI检查,采用UniSight系统进行半月板有关指标的测量。以性别、年龄、身高、体重为自变量,以胫骨平台冠状径（CWTP）、内侧胫骨平台冠状径（CWMTP）、内侧胫骨平台矢状径（SWMTP）、外侧胫骨平台冠状径（CWLTP）、外侧胫骨平台矢状径（SWLTP）、内侧半月板前角厚度（TAMM）、外侧半月板前角厚度（TALM）、内侧半月板后角厚度（TPMM）、外侧半月板后角厚度（TPLM）等指标为应变量,采用CHISS2006统计学软件进行统计学分析。结果胫骨平台冠状径、内侧胫骨平台矢状径、外侧胫骨平台矢状径、内外侧半月板后角厚度符合正态分布,测量的重复性好,数据稳定性好,与性别、身高有相关性,与年龄、体重无相关性。内侧胫骨平台冠状径、外侧胫骨平台冠状径、内外侧半月板前角厚度等指标受到的干扰因素较多,测量的重复性较差,数据稳定性欠佳,与自变量无相关性。结论胫骨平台冠状径、内侧胫骨平台矢状径、外侧胫骨平台矢状径、内外侧半月板后角厚度等指标可作为半月板移植前同种异体半月板匹配性测量的指标。     

人膝关节半月板不同测量方法的准确性和匹配性研究

目的：明确X线测量方法、MRI测量方法、解剖学测量方法三者的相互关系以及准确性和匹配性。方法选取意外死亡男性膝关节6只,年龄20～45岁,排除膝关节创伤和疾患,随机编号,分别行X线标准正侧位摄像、常规膝关节MRI扫描,将所得影像数据资料导入Unisight图象分析系统对相关指标进行测量并记录,然后将膝关节离断,直视下按照我院组织库的半月板测量方法进行测量并记录相关数据。X线测量指标包括：内侧胫骨平台矢状径、外侧胫骨平台矢状径、胫骨平台冠状径、内侧胫骨平台冠状径、外侧胫骨平台冠状径。MRI测量指标包括：胫骨平台冠状径、内侧胫骨平台冠状径、外侧胫骨平台冠状径、内侧胫骨平台矢状径、外侧胫骨平台矢状径、内外侧半月板的厚度（前角、体部、后角）、内外侧半月板的宽度（前角、体部、后角）。解剖学测量的指标包括：胫骨平台冠状径、内侧胫骨平台冠状径、外侧胫骨平台冠状径、内侧胫骨平台矢状径、外侧胫骨平台矢状径、内外侧半月板的厚度（前角、体部、后角）、内外侧半月板的宽度（前角、体部、后角）。结果在半月板测量的直接指标中,除内侧半月板体部宽度、内侧半月板前角厚度、外侧半月板体部厚度的MRI测量变异系数＜10%之外,所有指标变异系数均＞10%。外侧半月板后角宽度及外侧半月板前角宽度的MRI测量,变异系数分别为65.97%、70.26%。半月板测量的间接指标,变异系数均＜10%。半月板厚度的MRI测量总大于解剖学测量结果。3种测量方法的一致性方面存在关联,但仍有差异。结论半月板相关测量指标中,X线测量值均偏大,经MRI测量的指标与解剖学测量结果接近,MRI所测的半月板指标较X线测量指标更具准确性及稳定性,值得推荐其作为临床匹配性测量的方法,其中胫骨平台冠状径、内侧胫骨平台矢状径、外侧胫骨平台矢状径是稳定性最好的3个指标,变异系数均＜7%,且胫骨平台冠状径值得作为匹配性测量的首要指标。     

髌骨倾斜与外侧高压综合征的研究进展

髌骨倾斜是髌股关节的一种临床影像学表现,在侧位X线片、髌股关节轴位X线片、CT或MRI上都会出现髌骨倾斜的证据,它会使一些患者发生支持带劳损以及髌股外侧高压综合征。髌股外侧高压综合征（excessive lateral pressure syndrome,ELPS）又称为外侧髌骨挤压综合征,是由于髌骨无脱位的长期向外侧倾斜和外侧支持带适应性缩短以及内外侧关节面长期应力不平衡造成外侧髌股关节压力增高而出现的一系列症候群。