Joint magnetic resonance imaging: normal variants and pitfalls related to sports injury

MR imaging abnormalities, such as increased signal within normally hypointense structures, form and attachment abnormalities, fluid collections in joints, tendon sheaths and bursa, or even tumors, such as Morton's neuromas, are common in asymptomatic volunteers. They may be explained by normal physiology, anatomic variability, MR imaging artifacts, or true abnormalities without clinical importance. Although it is not always possible to differentiate such variants or artifacts from clinically relevant findings, it is important to know their potential cause and clinical importance and not to over-report them as abnormality requiring additional imaging or treatment. Thorough knowledge of normal anatomy is crucial in this situation.     

Tendon and ligament imaging

MRI and ultrasound are now widely used for the assessment of tendon and ligament abnormalities. Healthy tendons and ligaments contain high levels of collagen with a structured orientation, which gives rise to their characteristic normal imaging appearances as well as causing particular imaging artefacts. Changes to ligaments and tendons as a result of disease and injury can be demonstrated using both ultrasound and MRI. These have been validated against surgical and histological findings. Novel imaging techniques are being developed that may improve the ability of MRI and ultrasound to assess tendon and ligament disease.     

MR imaging of anatomical variants of ligaments, muscles and tendons at the ankle

PURPOSE: To illustrate the MR imaging features of anatomical variants of ligaments, muscles and tendons at the ankle. MATERIAL AND METHODS. The MRI features of the typical anatomy of the ankle is first reviewed in order to better understand the appearance of anatomical variants. The features of those anatomical variants are reported based on data from the literature and from a retrospective study of 63 ankle MRI and/or MR-arthrography performed for chronic instability. RESULTS: Ankle anatomical variants can be separated into 3 groups For each variant, we report the frequency, the differential diagnosis and the potential clinical consequence that may, at times, require a specific treatment. CONCLUSION: Anatomical variants are important to consider because these structures can simulate disease and can sometimes be symptomatic.     

Os peroneum friction syndrome complicated by sesamoid fatigue fracture: a new radiological diagnosis?

Injuries to the peroneal tendons are relatively common worldwide but tendon rupture without significant trauma is uncommon. Ankle mechanics can be seriously affected by disruption of one or both of the peroneal tendons although complete rupture can also remain asymptomatic. Accessory ossicles are sesamoid bones and are common findings in routine radiology of the foot and ankle. Although in the vast majority these "os" are normal variants of anatomy, they can lead to painful syndromes and suffer fractures and even undergo degenerative changes in response to overuse and trauma. Although similar syndromes have been discussed in the surgical literature, there is a lack of literature describing the use of modern imaging in the accurate diagnosis and its subsequent assistance towards appropriate management of os peroneum friction syndrome complicated by sesamoid fatigue syndrome. This article presents the plain film, sonographic and magnetic resonance imaging findings in a case of os peroneum friction syndrome complicated by a sesamoid fatigue fracture as well as reviewing the pertinent literature.     

Magnetic resonance imaging of tendon and ligament abnormalities: Part I. Spine and upper extremities

Magnetic resonance imaging (MRI) has proven to be an ideal technique for evaluating tendons and ligaments, which, because of their fibrous structure, have a low signal intensity on all sequences. Trauma and a wide variety of other conditions cause aberrations in the normal appearance of these structures, ranging from minor alterations in shape, size, appearance, and continuity to various changes in signal intensity within the tendon, tendon sheath, and ligament on different sequences. The purpose of this paper is to review MRI findings in patients with abnormalities of tendons and ligaments in the spine and upper extremities.     

MR imaging of soft-tissue masses of the foot

As with other parts of the musculoskeletal system, the soft tissues of the foot can be affected by a wide variety of pathologic entities including trauma, congenital abnormalities, infections, and neoplastic disorders. While plain radiographs are usually the initial examination for evaluation of pathology, magnetic resonance imaging (MRI) is critical to evaluate for abnormalities within the ligaments, tendons, and other nonosseous structures within the foot. The constellation of clinical and MRI findings often allows a relatively specific diagnosis to be rendered. This article discusses both benign and malignant processes within the soft tissues of the foot and presents their characteristic imaging findings with MRI.     

Magnetic resonance imaging of the shoulder in asymptomatic professional baseball pitchers.

The purpose of this study was to evaluate the magnetic resonance imaging findings in both shoulders of asymptomatic professional baseball pitchers. Fourteen pitchers who were without significant prior injury underwent a blinded clinical assessment and magnetic resonance imaging of both shoulders. All images were interpreted by two experienced musculoskeletal radiologists. The appearance of the rotator cuff tendons was graded, with additional evaluation of the biceps, labrum, and osseous structures. Ten athletes were found to have stable shoulders and painless full range of motion. Clinically, four athletes had at least a 40 degrees loss in internal rotation as compared with the nonthrowing arm. There were no significant differences in magnetic resonance imaging findings of the supraspinatus and infraspinatus tendons between the throwing and nonthrowing shoulders. The labrum was abnormal in 79% of the 28 shoulders. Enthesopathic changes of the posterior glenoid labrum were identified in the four pitchers who had loss of internal rotation. We conclude that unenhanced magnetic resonance imaging of the shoulder in asymptomatic high performance throwing athletes reveals abnormalities that may encompass a spectrum of "nonclinical" findings. These data can be useful in separating symptomatic pathologic findings from these variants. Enthesopathic changes of the posterior glenoid labrum in the throwing arm may represent an early Bennett-type lesion. The cause may be excessive traction on the posterior capsule during the pitching motion, with subclinical injury to this area.     

MR imaging of the normal ligaments and tendons of the ankle

The 10 major ligaments and nine major tendons of the ankle were evaluated in 17 ankle MR studies to determine the incidence of visualization of each structure in each of the three orthogonal planes. High-resolution technique was used, with 3 mm slice thickness and an in-plane resolution of 0.6 mm. Of the 19 ligaments and tendons evaluated, 18 demonstrated more than 70% frequency of visualization in at least one imaging plane. However, seven ligaments and three tendons demonstrated 0% visualization in at least one of the three orthogonal planes. Seven ligaments showed more than 70% visualization in only one plane (three coronal, two axial, two sagittal). Only the Achilles tendon and anterior tibial tendon demonstrated 100% visualization in all three planes. We conclude that all three orthogonal planes are essential to achieve optimal visualization of all of the major ligaments and tendons of the ankle. For specific evaluation of selected ligaments or tendons, only one or two planes may be required.     

Imaging of elbow injuries in the child and adult athlete

Because of the often complex and sometimes poorly remembered history of trauma to the elbow, imaging beyond conventional plain film radiographs is often needed. Usually, this consists of high-resolution MR imaging to evaluate the articular cartilage, supporting ligaments, and tendons about the elbow. Sonography, however, can also be used, especially when there is a targeted clinical question as to the presence of epicondylitis, or to provide guidance for diagnostic or therapeutic injections.     

MR imaging of ligament and tendon injuries of the fingers.

Magnetic resonance (MR) imaging can provide important information for diagnosis and evaluation of soft-tissue trauma in the fingers. An optimal imaging technique should include proper positioning, dedicated surface coils, and specific protocols for the suspected abnormalities. Familiarity with the fine anatomy of the normal finger is crucial for identifying pathologic entities. MR imaging is a powerful method for evaluating acute and chronic lesions of the stabilizing articular elements (volar plate and collateral ligaments) of the fingers and thumbs, particularly in the frequently affected proximal interphalangeal and metacarpophalangeal joints. As in other body regions, MR imaging is also useful for depicting traumatic conditions of the extensor and flexor tendons, including injuries to the pulley system. In general, normal ligaments and tendons have low signal intensity on MR images, whereas disruption manifests as increased signal intensity. Radiologists need to understand the full spectrum of finger abnormalities and associated MR imaging findings.     

Patellar tendon morphology in volleyball athletes with and without patellar tendinopathy

Appropriate management of patellar tendinopathy requires distinguishing between inflammatory and degenerative conditions, often difficult because tendon thickening can be a normal or pathological adaptation, and micromorphology is not observable on clinical imaging. The purpose of this study was to quantitatively examine patellar tendon micro‐ and macromorphology in volleyball athletes and relate those findings to reported symptoms. Longitudinal ultrasound images of proximal and distal patellar tendons were acquired from 84 male elite volleyball athletes (44 symptomatic, 40 asymptomatic) and 10 asymptomatic nonathlete controls. Micromorphology was determined using two‐dimensional Fast Fourier Transform analysis providing a discriminating peak spatial frequency parameter (PSF). Macromorphology (patellar tendon thickness) was measured using Image J software. All athletes regardless of symptoms had thicker proximal tendons compared to nonathletes, suggesting a normal adaptation to training loads. However, symptomatic athletes demonstrated lower PSF than asymptomatic athletes and nonathletes at the proximal tendon, suggesting greater collagen disorganization, and tendon degeneration rather than inflammation. Only symptomatic athletes had thicker distal tendons than nonathletes, but there was no difference in PSF distally. Diagnostic ultrasound enhances the understanding of the micromorphology of patellar tendons, supporting the rationale for management that remodels the degenerated tendon instead of treating inflammation.     

膝关节后内侧结构生物力学意义及损伤的MRI表现

目的:分析膝关节后内侧结构的解剖、生物力学特点及临床意义;阐述膝关节后内侧结构的MRI正常及损伤后表现;进行后内侧结构损伤MRl分级.方法:回顾分析87例后内侧结构、以及其他相关损伤的MRI所见.结果:本组87例后内侧结构损伤,Ⅰ级损伤29例,Ⅱ级47例,Ⅲ级11例;合并交叉韧带损伤34例(39%),内侧半月板后角撕裂...     

Founder’s lecture of the ISS 2006: borderlands of normal and early pathological findings in MRI of the foot and ankle

The purpose of this article is to highlight the anatomical variants, technical pitfalls, and the prevalence of abnormal conditions in the asymptomatic population in magnetic resonance imaging of the foot and ankle. Special attention is drawn to the complex anatomy of the deltoid ligament (the superficial tibionavicular ligament, tibiospring ligament, the tibiocalcaneal ligament, and the deep anterior and posterior tibiotalar ligaments) and the posterior tibial tendon insertion including the magic angle artifact and the high prevalence of asymptomatic findings such as "hypertrophied" peroneal tubercle (abnormal only when larger than 5 mm), peroneus quartus (prevalence 17%), and cysts (vascular remnants) just inferior to the angle of Gissane.     

Are ultrasound and magnetic resonance imaging of value in assessment of Achilles tendon disorders? A two year prospective study

OBJECTIVES: To (a) compare ultrasound (US; including grey scale and colour and power Doppler) and magnetic resonance imaging (MRI; with high resolution and fat saturation sequences) with a clinical yardstick in the evaluation of chronic Achilles tendinopathy, and (b) examine whether either imaging method predicted 12 and 24 month clinical outcome. METHODS: Forty five patients with symptoms in 57 Achilles tendons were diagnosed with tendinopathy by an experienced sports medicine doctor. All patients underwent US examination (12 MHz probe) with colour and power Doppler, and 25 consecutive patients also underwent MRI with high resolution T1 weighted and STIR sequences. RESULTS: US identified abnormal morphology in 37 of the 57 symptomatic tendons (65%) and normal morphology in 19 of 28 asymptomatic tendons (68%). Baseline US findings did not predict 12 month clinical outcome. The addition of colour and power Doppler did not improve the diagnostic performance of US. MRI identified abnormal morphology in 19 of 34 symptomatic tendons (56%) and normal morphology in 15 of 16 asymptomatic tendons (94%). Lesser grades of MR signal abnormality at baseline were associated with better clinical status at 12 month follow up. CONCLUSIONS: US and MRI show only moderate correlation with clinical assessment of chronic Achilles tendinopathy. Graded MRI appearance was associated with clinical outcome but US was not.     

Magnetic resonance imaging of ankle tendons and ligaments: part I - anatomy

Magnetic resonance imaging is an excellent technique for imaging the tendons and the ligaments of the ankle. Owing to the advantage of detailed demonstration of soft-tissue structures and capability for multiplanar demonstration of the ankle ligaments and tendons, MRI has been increasingly used in the evaluation of the ligamentous and the tendon injuries of the ankle. Knowledge of normal anatomy and of MRI appearances are essential to recognize pathological appearances. In this pictorial essay, the first of a three part series, we review the normal MRI appearances of the ankle tendons and ligaments. The anterior, lateral and medial tendon groups, the Achilles tendon and the lateral, the syndesmotic and the medial ligament groups are described and illustrated. Anatomy of the sinus tarsi is also described. Tendon and ligament pathology will be illustrated in the second part of the series, and imaging approach to ankle injuries will be outlined in the final part of this series.     

Calcifying tendinitis of the rotator cuff with cortical bone erosion

Calcifying tendinitis occurs most commonly in the rotator cuff tendons, particularly involving the supraspinatus tendon insertion, and is often asymptomatic. Cortical erosion secondary to calcifying tendinitis has been reported in multiple locations, including in the rotator cuff tendons. We present a pathologically proven case of symptomatic calcifying tendinitis involving the infraspinatus tendon with cortical erosion with correlative radiographic, CT, and MR findings. The importance of considering this diagnosis when evaluating lytic lesions of the humerus and the imaging differential diagnosis of calcifying tendinitis and cortical erosion are discussed.An erratum to this article can be found at     

Ultrasound of the Foot and Ankle

For specific indications, ultrasound is an inexpensive and efficient alternative to magnetic resonance (MR) imaging of the ankle and foot. In addition to the tendons, the anterior joint, retrocalcaneal bursa, ligaments, plantar fascia, and soft tissues can be imaged with ultrasound. Tenosynovitis, tendon tears and tendinosis, joint effusions, intra-articular loose bodies, ganglion cysts, plantar fasciitis, and Morton neuromas can be demonstrated with ultrasound. In most cases, a focused ankle or foot ultrasound can be performed more rapidly and efficiently than magnetic resonance imaging. Direct correlation with the site of pain and rapid comparison with the asymptomatic ankle are possible with this modality. As pressure for cost containment continues, demand for ultrasound of the ankle and foot will likely increase.     

MR morphology of alar ligaments and occipitoatlantoaxial joints: study in 50 asymptomatic subjects

PURPOSE: To assess the magnetic resonance (MR) imaging appearance of the alar ligaments and joints in the upper cervical spine to determine the prevalence of structural alterations in asymptomatic individuals. MATERIALS AND METHODS: Fifty healthy individuals (31 men, 19 women) with a mean age of 30 years (range, 19-47 years) underwent coronal T1- and T2-weighted and transverse T1-weighted MR imaging. MR findings were analyzed independently by two musculoskeletal radiologists, with disagreements resolved in conference. RESULTS: Alar ligaments were detected in 42 (84%) (left side) and 38 (76%) (right side) of 50 individuals. The majority of ligaments (88%) and joints (58%) of the craniocervical junction (CCJ) were asymmetric. Asymmetry of the joint between C1 and C2 was less frequent (46%). Small amounts of fluid were detected in 8% of CCJ joints and 56% of C1-C2 joints in asymptomatic individuals. CONCLUSION: Asymmetry of alar ligaments, CCJ and C1-C2 facet joints, and joint effusions are common in asymptomatic individuals. The clinical relevance of these MR findings is therefore limited in the identification of the source of neck pain in symptomatic patients.     

Tuberculosis arthritis and tenosynovitis

The incidence of extrapulmonary tuberculosis (TB) has been rising due to the increasing number of immunosuppressed patients. Musculoskeletal system accounts for 25% of extrapulmonary TB. Most of the musculoskeletal TB involves the spine. TB of peripheral joints and tendons occur infrequently, but if untreated, it can cause serious joint and tendon destruction as well as spread of the infection to the surrounding bursa, muscle, and other soft tissues. The diagnosis of TB of joints and tendons is difficult due to the nonspecific clinical manifestations and imaging features. Concurrent active pulmonary TB is present in <50% of the patients. A positive chest radiographic finding or a positive tuberculin test supports the diagnosis, but negative results do not exclude diagnosis. Although imaging features of TB of joints and tendons are nonspecific, certain findings such as relatively preserved joint space, juxta-articular osteoporosis, cold abscesses, para-articular soft tissue calcification, and rice bodies are suggestive of TB infection. Familiarity with these imaging features can help in making an early diagnosis and facilitating proper management.