MR imaging features of foot involvement in ankylosing spondylitis

Ultrasound of the Foot and Ankle in Peripheral Spondyloarthritis

Seronegative spondyloarthritis (SpA) is an umbrella term that includes ankylosing spondylitis (AS), psoriatic arthritis, reactive arthritis, and arthritis related to inflammatory bowel disease. Apart from AS, these other conditions predominantly affect the appendicular skeleton. Both the foot and ankle are frequently involved peripheral joints. According to the latest Assessment of Spondyloarthritis International Society criteria, imaging is a key way to diagnose peripheral seronegative SpA. Common imaging features are enthesitis, synovitis, tenosynovitis, erosive and bone-proliferative changes in the affected joints, and effusion.Although magnetic resonance imaging is the gold standard technique, ultrasound (US) is a cost-effective imaging method that can readily detect the features just described. Additionally, it can semi-quantify inflammatory changes, helping in treatment and dose modifications. Imaging-guided procedures, such as biopsies and steroid injections, are routinely performed using US. Furthermore, US can easily be deployed at outpatient rheumatology clinics, making it an ideal point-of-care investigation.

Conventional radiography and correlated factors of enthesopathies of the Achilles tendon and plantar fascia in patients with axial spondyloarthritis

OBJECTIVE

This study aimed to investigate the correlated risk factors and presence of radiological enthesopathies of the Achilles tendon and plantar fascia in patients with axial spondyloarthropathy (axSpA).

METHODS

242 patients (121 female and 121 male) with axSpA were included in this study. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI), the Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP), the Bath Ankylosing Spondylitis Radiology Index (BASRI), the Maastricht Ankylosing Spondylitis Enthesitis Score (MASES), and CRP were evaluated in all patients. The lateral foot X-rays of the patients were assessed for enthesopathies of the Achilles tendon and plantar fascia attachments.

RESULTS

Calcaneal spur and Achilles enthesopathies were present in 57.4% of the patients. 39.3% of patients had enthesopathies in both regions. The male and female groups differed statistically in terms of weight, height, body mass index (BMI), positive family history, and duration since diagnosis (p<0.05). The presence of calcaneal spur and Achilles enthesopathies was found to be significantly correlated with age, weight, BMI, symptom duration, and the scores of BASDAI, BASFI, ASDAS-CRP, BASRI, and MASES (p<0.05).

CONCLUSIONS

The presence of enthesopathies appears to be associated with age, weight, BMI, symptom duration, and disease activity. Conventional radiography can be used as an auxiliary tool in the evaluation of entheseal abnormalities in patients with SpA, especially in patients with advanced age, long symptom duration, and high BMI.

Ankle and Foot: Focus on Inflammatory Disease

The ankle and foot have numerous bones and complex joints that can be affected by several types of inflammatory arthritis with different patterns and various radiologic signs, depending on the phase of the disease. Involvement of these joints is most frequently seen in peripheral spondyloarthritis and rheumatoid arthritis in adults and juvenile idiopathic arthritis in children. Although radiographs are a mainstay in the diagnostic process, ultrasonography and especially magnetic resonance imaging allow early diagnosis and are crucial diagnostic tools. Some diseases have typical features based on target populations (e.g., adults versus children, men versus women), but others may have overlapping imaging characteristics. We highlight key diagnostic features and describe appropriate investigations to guide clinicians toward the correct diagnosis and provide support during disease monitoring.

The value of different involvement patterns of the knee "synovio-entheseal complex" in the differential diagnosis of spondyloarthritis, rheumatoid arthritis, and osteoarthritis: an MRI-based study

OBJECTIVES

To explore the different involvement patterns of the knee "synovio-entheseal complex (SEC)" on MRI in patients with spondyloarthritis (SPA), rheumatoid arthritis (RA), and osteoarthritis (OA).

METHODS

This study retrospectively included 120 patients (male:female, 55:65) with a mean age of 39.20 years diagnosed with SPA (n = 40), RA (n = 40), and OA (n = 40) at the First Central Hospital of Tianjin between January 2020 and May 2022. Six knee entheses were assessed by two musculoskeletal radiologists according to the SEC definition. Bone marrow lesions associated with entheses include bone marrow edema (BME) and bone erosion (BE), which were classified as entheseal or peri-entheseal based on their relationship to the entheses. Three groups (OA, RA, and SPA) were established to characterize the location of enthesitis and the different SEC involvement patterns. Inter-group and intra-group differences were analyzed using the ANOVA or chi-square tests, and the inter-class correlation coefficient (ICC) test was used to determine inter-reader agreement.

RESULTS

The study contained a total of 720 entheses. The SEC-based analysis revealed different involvement patterns in three groups. The OA group had the most abnormal signals in tendons/ligaments (p = 0.002). The RA group had considerably greater synovitis (p = 0.002). The majority of peri-entheseal BE was identified in the OA and RA groups (p = 0.003). Furthermore, entheseal BME in the SPA group was significantly different from those in the other two groups (p < 0.001).

CONCLUSIONS

SEC involvement patterns differed in SPA, RA, and OA, which is important for differential diagnosis. SEC should be used as a whole evaluation method in clinical practice.

KEY POINTS

• The "synovio-entheseal complex (SEC)" explained differences and characteristic alterations in the knee joint in patients with spondyloarthritis (SPA), rheumatoid arthritis (RA), and osteoarthritis (OA). • The various SEC involvement patterns are crucial for differentiating SPA, RA, and OA. • When "knee pain" is the only symptom, a detailed identification of characteristic alterations in the knee joint of SPA patients may help timely treatment and delay the structural damage.

Foot Deformity in Patients With Ankylosing Spondylitis: Is It Associated With Functionality and Disease Activity?

Foot involvement affects mobility and functionality in patients with ankylosing spondylitis but it remains unknown if foot deformities in ankylosing spondylitis patients affect functionality, disease activity, and quality of life. The aim of this study was to evaluate in detail the presence of a relationship between radiologically detected foot deformities in ankylosing spondylitis patients and both clinical and electrophysiological findings. The cross-sectional study included 110 patients with ankylosing spondylitis who were diagnosed according to the Assessment in Spondyloarthritis International Society criteria and were followed in our hospital. Demographic and clinical data of all patients were recorded. Bilateral lateral foot x-rays and electrophysiology examinations were evaluated in all subjects. The arch in the dominant foot of the patients was classified in 3 groups as pes cavus, pes planus, or normal. The clinical outcomes, physical examination and electrophysiological findings were compared between the groups, and correlations were examined of the foot deformities with these parameters. Foot deformities were determined at a high rate (74.5%). These deformities affected foot pain, disability and quality of life. Pes cavus deformity was found to be associated with hip pain and enthesopathy. In the electrophysiological studies, the presence of pes planus was found to be associated with the findings of the tibial and sural nerve conduction studies, and the presence of pes cavus with the findings of the peroneal nerve conduction study. In conclusion, foot deformities may have an effect on the quality of life and functionality in ankylosing spondylitis patients.

Complete Bilateral Ankle Fusion: A Rare Complication of Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disorder primarily affecting the axial skeleton and is strongly associated with a positive human leukocyte antigen B27 (HLA-B27) genotype. Patients typically present with chronic low back pain that typically starts before the age of 40 years. Common initial clinical features include lower back, hip, and joint pain with stiffness that is worse in the morning and with inactivity. As the disease progresses over a prolonged period, it leads to fusion of sacroiliac joints and ankylosis of the vertebrae with the iconic "bamboo spine" on imaging. Joint fusion or ankylosis is the sequela of either undiagnosed or untreated AS. We report a case of a 69-year-old male with complete fusion of the ankle joint, hindfoot, and midfoot of both feet in the clinical context of an incidental finding of an ankylosed spine on computed tomography (CT) imaging. The ankle joint is a very uncommon site for fusion in ankylosing spondylitis. We would like to suggest the terminology “boot sign” for this rare radiographic finding of complete ankle and subtalar fusion given the appearance of a boot. “Boot sign” is associated with either inability to ambulate or a steppage gait from loss of ankle dorsiflexion as a result of ankle and hindfoot fusion with or without fusion of forefoot and midfoot.

The efficacy and safety of extracorporeal shock wave therapy on plantar fasciitis in patients with axial spondyloarthritis: a double-blind, randomized controlled trial

The efficacy and safety of extracorporeal shock wave therapy (ESWT) on chronic plantar fasciitis (PF) in patients with axial spondyloarthritis (axSpA) remain unclear. To investigate the efficacy and tolerability of ESWT in patients with PF in axSpA. In this double-blind, randomized controlled trial, 22 axSpA patients with PF who had heel pain above 5 according to visual analog scale (VAS) over 3 months were randomly divided into 2 groups: ESWT and sham-ESWT. Both groups received a total of three treatments at 1-week intervals. All patients were assessed by the VAS, heel pressure algometry, Foot Function Index (FFI), and plantar fascia ultrasonography (thickness and morphology) at baseline, 1 week after each session, 4th and 8th week after the last therapy. The mean ± SD ages of the ESWT and sham-ESWT groups were 43.8 ± 8.2 and 48.5 ± 7.6 years, respectively. Significant time effects between the time points were observed in both groups in terms of VAS, pressure algometry, and FFI. There was a statistically significant decrease in pain, an increase in perceived pressure algometry values, and an improvement in activity restriction in the ESWT group compared to the sham-ESWT group. There was not a change in the plantar fascia thickness before and after the intervention in both groups. No side effects were observed during the treatment and follow-up. ESWT appears to be a safe and well-tolerated physical therapy modality for improving chronic refractory heel pain due to PF in patients with axSPA. This trial was registered to The Australian New Zealand clinical trial with the registration number ACTRN12618001954213. The enrollment began in 15/12/2018 and data collection stopped in 29/05/2020.

Inflammatory Foot Involvement in Spondyloarthritis: From Tarsitis to Ankylosing Tarsitis

Spondyloarthritis (SpA) is a group that includes a wide spectrum of clinically similar diseases manifested by oligoarticular arthritis and axial or peripheral ankylosis. Although axial SpA is predominant in Caucasians and adult-onset patients, juvenile-onset and Latin American patients are characterized by severe peripheral arthritis and particularly foot involvement. The peripheral involvement of SpA can vary from tarsal arthritis to the most severe form named ankylosing tarsitis (AT). Although the cause and etiopathogenesis of axSpA are often studied, the specific characteristics of pSpA are unknown. Several animal models of SpA develop initial tarsitis and foot ankylosis as the main signs, emphasizing the role of foot inflammation in the overall SpA spectrum. In this review, we attempt to highlight the clinical characteristics of foot involvement in SpA and update the knowledge regarding its pathogenesis, focusing on animal models and the role of mechanical forces in inflammation.

Static foot posture and its relation to clinical variables in ankylosing spondylitis

AIM

Postural abnormalities of the foot are common in rheumatic diseases. Static foot posture is a poorly studied clinical parameter in ankylosing spondylitis (AS). The aim of the study was to evaluate static foot posture in patients with AS and to determine the potential impact of clinical variables on foot posture.

METHOD

Fifty patients with AS and 40 age- and sex-matched healthy controls were enrolled in the study. Disease activity was measured using the Ankylosing Spondylitis Disease Activity Score. Axial mobility was evaluated with the Bath Ankylosing Spondylitis Metrology Index three-point answer scale. Functional status was assessed by the Bath Ankylosing Spondylitis Functional Index and Health Assessment Questionnaire-Disability Index. Enthesitis and foot posture were evaluated by the Maastricht Ankylosing Spondylitis Enthesitis Score (MASES) and Foot Posture Index-6, respectively.

RESULTS

Patients with AS revealed significantly higher scores of foot posture index when compared with controls (P = 0.005). Abnormal foot posture (pronated and supinated) was more common in the patient group (P < 0.01). According to the multinomial logistic regression analysis, a higher MASES score was associated with supinated foot posture in AS patients (odds ratio 1.47, 95% confidence interval 1.03-2.09, P = 0.035). In addition, supinated foot posture was associated with enthesitis of the Achilles tendon (P = 0.002).

CONCLUSION

Enthesitis is related to deteriorated static foot posture in patients with AS. Enthesitis of the Achilles tendon is closely associated with the supinated foot posture.

A Narrative Review of the Classification and Use of Diagnostic Ultrasound for Conditions of the Achilles Tendon

Enthesitis is a cardinal feature of spondyloarthropathies. The Achilles insertion on the calcaneus is a commonly evaluated enthesis located at the hindfoot, generally resulting in hindfoot pain and possible tendon enlargement. For decades, diagnosis of enthesitis was based upon patient history of hindfoot or posterior ankle pain and clinical examination revealing tenderness and/or enlargement at the site of the tendon insertion. However, not all hindfoot or posterior ankle symptoms are related to enthesitis. Advanced imaging, including magnetic resonance imaging (MRI) and ultrasound (US), has allowed for more precise evaluation of hindfoot and posterior ankle conditions. Use of US in diagnosis has helped confirm some of these cases but also identified other conditions that may have otherwise been misclassified without use of advanced imaging diagnostics. Conditions that may result in hindfoot and posterior ankle symptoms related to the Achilles tendon include enthesitis (which can include retrocalcaneal bursitis and insertional tendonopathy), midportion tendonopathy, paratenonopathy, superficial calcaneal bursitis, calcaneal ossification (Haglund deformity), and calcific tendonopathy. With regard to classification of these conditions, much of the existing literature uses confusing nomenclature to describe conditions in this region of the body. Some terminology may imply inflammation when in fact there may be none. A more uniform approach to classifying these conditions based off anatomic location, symptoms, clinical findings, and histopathology is needed. There has been much debate regarding appropriate use of tendonitis when there is no true inflammation, calling instead for use of the terms tendinosis or tendonopathy. To date, there has not been clear examination of a similar overuse of the term enthesitis in conditions where there is no underlying inflammation, thus raising the need for more comprehensive taxonomy.

Traumatic and non-traumatic bone marrow edema in ankle MRI: a pictorial essay

Bone marrow edema (BME) is one of the most common findings on magnetic resonance imaging (MRI) after an ankle injury but can be present even without a history of trauma. This article will provide a systematic overview of the most common disorders in the ankle and foot associated with BME.

The presence of BME is an unspecific but sensitive sign of primary pathology and may act as a guide to correct and systematic interpretation of the MR examination. The distribution of BME allows for a determination of the trauma mechanism and a correct assessment of soft tissue injury. The BME pattern following an inversion injury involves the lateral malleolus, the medial part of the talar body, and the medial part of the distal tibia. In other cases, a consideration of the distribution of BME may indicate the mechanism of injury or impingement. Bone in direct contact with a tendon may lead to alterations in the bone marrow signal where BME may indicate tendinopathy or dynamic tendon dysfunction. Changed mechanical forces between bones in coalition may lead to BME. Degenerative changes or minor cartilage damage may lead to subchondral BME. Early avascular necrosis, inflammation, or stress fracture may lead to more diffuse BME; therefore, a detailed medical history is crucial for correct diagnosis.

A systematic analysis of BME on MRI can help to determine the trauma mechanism and thus assess soft tissue injuries and help to differentiate between different etiologies of nontraumatic BME.

Evaluation of plantar fascia using high-resolution ultrasonography in clinically diagnosed cases of plantar fasciitis

Purpose

The aim of this study was to assess the efficacy of high-resolution ultrasonography in the assessment of plantar fascia in individuals with heel pain, before and after treatment.

Material and methods

This study was conducted from 2016 to 2019, during which time 44 clinically diagnosed patients of plantar fasciitis were compared to 50 normal volunteers. There were 25 males and 25 females in the control group and 42 females and two males in the study group. Thirty-eight patients had unilateral disease, and six patients had bilateral disease. The thickness of the plantar fascia was measured just anterior to its calcaneal attachment using ultrasonography. Body mass index (BMI) was also calculated in both groups.

Results

The plantar fascia was 2-4 mm thick in the control group whereas it was > 4 mm thick in 48 heels in the study group. With cut-off of > 4 mm as diagnostic of plantar fasciitis, this study had a sensitivity of 96%, specificity of 100%, and accuracy of 98%. BMI was increased in 60% of female patients. All patients were treated with local infiltration of corticosteroid. In 37/42 patients (43 heels) who had improved clinically, the thickness of plantar fascia was reduced to < 4 mm when assessed after six weeks of corticosteroid injection.

Conclusions

Diagnosis of plantar fasciitis can be easily verified by ultrasonography with plantar fascia thickness > 4 mm being suggestive of plantar fasciitis. Ultrasound can also be used to evaluate treatment response. Ultrasono-graphy helps the clinician in confirming the diagnosis of plantar fasciitis and also in assessing the response to treatment.

Ultrasound follow-up of spontaneous tears of the plantar fascia treated with conservative therapies: Two case reports

RATIONALE

The plantar fascia (PF) is an important anatomical structure that stabilizes the longitudinal arch of the foot. While plantar fasciitis is a common pathology affecting the foot, tears of the PF are uncommon injuries characterized by acute pain in the plantar aspect of the foot. The main purpose of this paper was to describe, in detail, how the ultrasonographic pattern of PF rupture can be combined with the clinical features to define the prognosis and promptly plan the therapeutic approach.

PATIENT CONCERNS

In the first case, a 39-year-old male patient was seen due to acute pain in the mid plantar foot which appeared 3 days after a tennis match. The pain was accompanied by a "snap" noise and intense pain. In the second case, a 44-year-old male patient was seen due to pain in the heel region which appeared 2 days after a running session.

DIAGNOSIS

One case of noninsertional complete tear of the central bundle of the PF with retraction of the 2 stumps and 1 case of partial tear of the central bundle of the PF at the level of the insertional region.

INTERVENTIONS

Both patients were treated with conservative therapies including load management, oral nonsteroidal anti-inflammatory drugs, foot orthosis, and restriction of sport activities.

OUTCOMES

At follow-up, the patient with spontaneous complete tear of the PF (noninsertional area) showed a small fibrous bridge between the 2 stumps, with partial alignment of the proximal and distal portions, the ability to walk for a medium to long-distance, and difficulty going up and downstairs. The patient with the spontaneous partial tear (insertional area) showed complete fibrous scar tissue with restoration of the fascial continuity, and the ability to walk for a long-distance and go up and downstairs without pain.

LESSONS

Based on the clinical and ultrasonographic findings, we suggest that partial tear of the PF in the insertional region presents a favorable prognosis with complete recovery, both clinically and anatomically, while a complete tear in the noninsertional region is associated with partial functional and histological recovery when managed with a conservative approach. Therefore, coupling the clinical findings with the sonohistologic pattern is a valuable approach to plan the most suitable treatment for patients with spontaneous PF tear.

Utility of Magnetic Resonance Imaging in Diagnosis and Monitoring Enthesitis in Patients with Spondyloarthritis: An OMERACT Systematic Literature Review

Objective.

A systematic literature review was performed to document published magnetic resonance imaging (MRI) lesion definitions and scoring systems for enthesitis in spondyloarthritis (SpA).

Methods.

PubMed, Embase, and Cochrane Library databases were searched for original publications involving adult patients with SpA undergoing MRI of axial/peripheral joints. Selected articles were assessed for quality using a standardized assessment tool and metric indices.

Results.

Considering the heterogeneous design, quality, and outcome measures of studies, statistical data pooling was considered inappropriate. A qualitative narrative of results was undertaken based on study designs.

Conclusion.

Lack of a comprehensive, validated score warrants additional research to develop an MRI enthesitis scoring system. PROSPERO registration number: CRD42018090537.

Radiologic features in symptomatic/asymptomatic heels of patients with ankylosing spondylitis

AIM

Most heel pain occurs at the posterior or plantar aspect, where main entheses of the heel are located. However, simple radiographs as basic work-up tools, their features based on their association with local symptoms in the heel in ankylosing spondylitis (AS) patients, have rarely been described.

METHOD

Forty patients with AS and unilateral heel pain were enrolled to evaluate radiographic differences between symptomatic and asymptomatic heels. The two groups were assessed according to symptom location: posterior (group PS) or plantar (group PL). Typical abnormalities in bone and/or soft tissue on the heel due to inflammation were compared.

RESULTS

In group PS (20 cases), 19 (95%) symptomatic feet and 7 (35%) asymptomatic feet showed abnormal findings on the posterior heel and symptomatic feet showed 6 (30%) plantar abnormalities. Erosion of the posterior calcaneal tuberosity, obliteration of the retrocalcaneal recess (RR), and swelling shadows with increased thickness on posterior soft tissue were observed more frequently and significantly in symptomatic feet in group PS (P < 0.05). In group PL (20 cases), 11 (55%) symptomatic feet and 8 (40%) asymptomatic feet showed abnormalities on the plantar heel and symptomatic feet showed 14 (70%) posterior abnormalities, and none showed significant differences between symptomatic and asymptomatic feet.

CONCLUSION

Among simple radiographic alterations on heels with AS, such changes around the enthesis of the Achilles as bony erosion and RR obliteration with swollen posterior soft tissue are strongly related to current painful posterior heels. Assessment of enthesitis of the Achilles tendon in AS using plain radiography seems to be valid.

Whole-body Magnetic Resonance Imaging in Axial Spondyloarthritis: Reduction of Sacroiliac, Spinal, and Entheseal Inflammation in a Placebo-controlled Trial of Adalimumab

Objective.

To investigate whether adalimumab (ADA) reduces whole-body (WB-) magnetic resonance imaging (MRI) indices for inflammation in the entheses, peripheral joints, sacroiliac joints, spine, and the entire body in patients with axial spondyloarthritis (axSpA).

Methods.

An investigator-initiated, randomized, placebo-controlled, double-blinded 48-week followup trial included 49 patients with axSpA, who had Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) ≥ 4.0 despite treatment with nonsteroidal antiinflammatory drugs and a clinical indication for tumor necrosis factor inhibitor treatment. Patients were randomized to subcutaneous ADA 40 mg or placebo every other week for 6 weeks; thereafter, all patients received ADA. Conventional MRI and WBMRI were performed at weeks 0, 6, 24, and 48. The primary WBMRI endpoint was the proportion of patients with an improvement in WBMRI total inflammation index above the smallest detectable change (SDC) at Week 6.

Results.

The primary WBMRI endpoint (improvement of SDC > 2.3) was met in 11 (44%) patients in the ADA group and 3 (13%) patients in the placebo group (p = 0.025, Fisher’s exact test). The primary conventional MRI endpoint, the minimally important change in Spondyloarthritis Research Consortium of Canada Spine MRI Inflammation Index at Week 6, was achieved by 9 (36%) patients in the ADA group and 4 (17%) patients in the placebo group (p = 0.20). The primary clinical endpoint, BASDAI reduction > 50% or 2.0 at Week 24, was attained by 32 (65%) patients.

Conclusion.

ADA provided significant reductions in WBMRI indices of peripheral, axial, and whole-body inflammation in patients with axSpA. WBMRI is promising for objective assessment and monitoring of peripheral and axial disease activity in future clinical trials.

Ultrasonography assessment of heel entheses in patients with spondyloarthritis: a comparative study with magnetic resonance imaging and conventional radiography

The aim of the present study was to determine the agreement between ultrasonography (US), magnetic resonance imaging (MRI), and conventional radiography (CR) in the detection of findings indicative of enthesopathy in spondyloarthritis (SpA) patients. A cross-sectional study was performed in 40 SpA patients. Heel entheses (Achilles tendon and plantar fascia) were bilaterally examined by US, MRI, and CR. The three imaging modalities were carried out by three independent operators blinded to the other imaging modality data. Soft tissue abnormalities indicative of enthesopathy as thickening, structural changes, and bursitis were assessed by both US and MRI, and cortical bone abnormalities indicative of enthesopathy as erosions and enthesophytes were assessed by the three imaging modalities. The unweighted kappa values between US and MRI were 0.80, 0.66, 0.69, 0.70, and 0.70 for thickening, structural changes, bursitis, enthesophytes, and bone erosions, respectively. With respect to the detection of enthesophytes, the unweighted kappa values between CR and both US and MRI were 0.78 and 0.76, respectively. At last, for the recognition of bone erosions, the unweighted kappa values between CR and both US and MRI were 0.38 and 0.45, respectively. Using MRI as standard reference method, US was more sensitive with respect to CR revealing bone erosions. The present study provides evidence about the high overall agreement between US and MRI for all abnormal comparable findings at entheseal level and between US, MRI, and CR for the detection of enthesophytes in SpA patients.

Ultrasound Features of the Posterior Tibialis Tendon and Peroneus Brevis Tendon Entheses: Comparison Study Between Healthy Adults and Those With Inflammatory Arthritis

OBJECTIVE

Limited literature exists on the sonographic appearance of the posterior tibialis tendon (PTT) and the peroneus brevis tendon (PBT) entheses. We determined the anatomic features and best imaging techniques of normal PTT and PBT using musculoskeletal ultrasound and compared these findings to subjects with inflammatory arthritis.

METHODS

Adult subjects were enrolled as healthy controls (HCs), rheumatoid arthritis (RA) patients, or spondyloarthropathy (SpA) patients. Bilateral PTT and PBT entheses were imaged longitudinally, comparing 2 angles of insonation: perpendicular to the skin surface and 45° cephalad. Images were scored on semiquantitative scales assessing pathology.

RESULTS

A total of 78 subjects were enrolled (37 HC, 21 RA, and 20 SpA). Complete enthesis visualization was achieved more frequently in the perpendicular than in the cephalad view for the PBT (76.3% versus 58.7%), but more frequently in the cephalad view for the PTT (58.0% versus 19.6%). RA and SpA subjects had higher rates of PTT fiber disruption (P < 0.001), PTT tenosynovial effusion (P < 0.001), and Doppler signal (P < 0.001) than HCs. No significant differences existed at the PBT enthesis. In multivariate analysis, RA and SpA subjects were found to be 5.1 times (P < 0.001) and 3.6 times (P < 0.001) more likely to exhibit ultrasound-detected pathology, respectively, than HCs.

CONCLUSION

The perpendicular transducer aim is optimal for imaging the PBT, while the cephalad transducer orientation was more effective for evaluation of the PTT. Unlike distal PBT imaging, PTT imaging distinguished healthy and disease states, with both RA and SpA patients showing features of PTT enthesopathy. Distal PTT imaging is a useful technique for musculoskeletal ultrasound.

Imaging of plantar fascia disorders: findings on plain radiography, ultrasound and magnetic resonance imaging

Plantar fascia (PF) disorders commonly cause heel pain and disability in the general population. Imaging is often required to confirm diagnosis. This review article aims to provide simple and systematic guidelines for imaging assessment of PF disease, focussing on key findings detectable on plain radiography, ultrasound and magnetic resonance imaging (MRI). Sonographic characteristics of plantar fasciitis include PF thickening, loss of fibrillar structure, perifascial collections, calcifications and hyperaemia on Doppler imaging. Thickening and signal changes in the PF as well as oedema of adjacent soft tissues and bone marrow can be assessed on MRI. Radiographic findings of plantar fasciitis include PF thickening, cortical irregularities and abnormalities in the fat pad located deep below the PF. Plantar fibromatosis appears as well-demarcated, nodular thickenings that are iso-hypoechoic on ultrasound and show low-signal intensity on MRI. PF tears present with partial or complete fibre interruption on both ultrasound and MRI. Imaging description of further PF disorders, including xanthoma, diabetic fascial disease, foreign-body reactions and plantar infections, is detailed in the main text. Ultrasound and MRI should be considered as first- and second-line modalities for assessment of PF disorders, respectively. Indirect findings of PF disease can be ruled out on plain radiography.

Teaching Points

• PF disorders commonly cause heel pain and disability in the general population.

• Imaging is often required to confirm diagnosis or reveal concomitant injuries.

• Ultrasound and MRI respectively represent the first- and second-line modalities for diagnosis.

• Indirect findings of PF disease can be ruled out on plain radiography.

Functional limitations due to foot involvement in spondyloarthritis

[Purpose] Spondyloarthritis is a major inflammatory disease followed-up in the rheumatology clinics, foot involvement in spodyloarthritis is common. The functional states of patients with spondyloarthritis are usually evaluated globally. The aim of this study was to assess the foot involvement-related functional limitations in patients with spondyloarthritis. [Subjects and Methods] Patients with ankylosing spondylitis and psoriatic arthritis with foot pain more than 4 weeks who underwent anteroposterior and lateral feet radiography were enrolled into the study. A “clinical findings score” was calculated by assigning 1 point for every finding of swelling, redness, and tenderness. C-reactive protein and erythrocyte sedimentation rate were used as serum markers for disease activity. Foot radiograms were evaluated using the spondyloarthropathy tarsal radiographic index and the foot-related functional state of patients was determined by the Turkish version of the Foot and Ankle Outcome Score. [Results] There were no relationships between Foot and Ankle Outcome Score subscales and clinical findings score, serum markers, or radiologic score. Pain and symptoms subscale scores were result positively correlated with activity of daily living, sport and recreation, and quality of life subscale scores. [Conclusion] Pain and symptoms are the main determinants of foot-related functional limitations in spondyloarthritis.

Objective assessment of corticosteroid effect in plantar fasciitis: additional utility of ultrasound

BACKGROUND

although plantar fascia thickening is well documented as a sonographic criterion for the diagnosis of plantar fasciitis (PF), however it was less evaluated as an objective measure of response to treatment. It is unknown to what extent if any different responses to different treatments are related to the ultrasound (US) morphology changes. We aimed to evaluate changes in US findings in correlation to pain reported.

METHODS

this prospective observational trial included 21 plantar fasciitis patients (26 feet), resistant to conservative treatment for at least 2 months. Plantar fascia thickness and echogenicity were evaluated, compared to asymptomatic feet and correlated with visual analogue scale (VAS) and Heel Tenderness Index (HTI), before and after dexam-ethasone (DXM) iontophoresis in group I, and DXM injection in group II.

RESULTS

increased thickness and reduced echogenicity were constant in symptomatic feet, with high statistical significant difference compared to asymptomatic side. Correlation between plantar fascia thickness with VAS and HTI before and after treatment showed statistically significant positive correlation (p<0.05). ROC curve test showed that reduction of plantar fascia thickness by US in response to DXM had 100% sensitivity, 65.2% specificity and 69% accuracy, with higher specificity and accuracy than VAS.

CONCLUSION

US changes showed concurrent validity correlated with self-reported clinical improvement. Accordingly, ultrasound can be considered an objective useful tool for monitoring response to corticosteroid in patients with plantar fasciitis.

[Enthesitis in connection with spondyloarthritides]

Enthesitis is a frequent manifestation in spondyloarthritis (SpA) and psoriatic arthritis (PsA) and can be found in up to 40% of patients with SpA. Because of the pathognomonic relevance the classification criteria for SpA and PsA use enthesitis as an entrance or secondary criterion. Enthesitis is most frequently localized at the heel but it can occur at any insertion of an enthesis into the bone. When diagnosing enthesitis differential diagnoses should be considered, mechanical-degenerative causes and fibromyalgia in particular should be excluded. The imaging techniques power Doppler ultrasound (PDUS) and magnetic resonance imaging (MRI) are most helpful in making the diagnosis. The therapeutic options for enthesitis are limited. Nonsteroidal antirheumatic drugs (NSARD) and local injections of corticosteroids are recommended. In small clinical trials no efficacy of disease modifying antirheumatic drugs (DMARD) could be demonstrated. In contrast, tumor necrosis factor alpha (TNF-alpha) blockers were shown to be highly effective in randomized controlled trials for SpA and PsA but they are not currently approved for enthesitis only.

[Enthesitis in the context of spondyloarthritides]

Enthesitis is a frequent manifestation in spondyloarthritis (SpA) and psoriatic arthritis (PsA) and can be found in up to 40 % of patients with SpA. Because of the pathognomonic relevance the classification criteria for SpA and PsA use enthesitis as an entrance or secondary criterion. Enthesitis is most frequently localized at the heel but it can occur at any insertion of an enthesis into the bone. When diagnosing enthesitis differential diagnoses should be considered, mechanical-degenerative causes and fibromyalgia in particular should be excluded. The imaging techniques power Doppler ultrasound (PDUS) and magnetic resonance imaging (MRI) are most helpful in making the diagnosis. The therapeutic options for enthesitis are limited. Nonsteroidal antirheumatic drugs (NSARD) and local injections of corticosteroids are recommended. In small clinical trials no efficacy of disease modifying antirheumatic drugs (DMARD) could be demonstrated. In contrast, tumor necrosis factor alpha (TNF-alpha) blockers were shown to be highly effective in randomized controlled trials for SpA and PsA but they are not currently approved for enthesitis only.

Magnetic resonance imaging of pelvic entheses--a systematic comparison between short tau inversion recovery (STIR) and T1-weighted, contrast-enhanced, fat-saturated sequences

OBJECTIVE

To assess the contribution of contrast material in detecting and evaluating enthesitis of pelvic entheses by MRI.

MATERIALS AND METHODS

Sixty-seven hip or pelvic 1.5-T MRIs (30:37 male:female, mean age: 53 years) were retrospectively evaluated for the presence of hamstring and gluteus medius (GM) enthesitis by two readers (a resident and an experienced radiologist). Short tau inversion recovery (STIR) and T1-weighted pre- and post-contrast (T1+Gd) images were evaluated by each reader at two sessions. A consensus reading of two senior radiologists was regarded as the gold standard. Clinical data was retrieved from patients' referral form and medical files. Cohen's kappa was used for intra- and inter-observer agreement calculation. Diagnostic properties were calculated against the gold standard reading.

RESULTS

A total of 228 entheses were evaluated. Gold standard analysis diagnosed 83 (36%) enthesitis lesions. Intra-reader reliability for the experienced reader was significantly (p = 0.0001) higher in the T1+Gd images compared to the STIR images (hamstring: k = 0.84/0.45, GM: k = 0.84/0.47). Sensitivity and specificity increased from 0.74/0.8 to 0.87/0.9 in the STIR images and T1+Gd sequences. Intra-reader reliability for the inexperienced reader was lower (p > 0.05).

CONCLUSIONS

Evidence showing that contrast material improves the reliability, sensitivity, and specificity of detecting enthesitis supports its use in this setting.

Role of sonography and magnetic resonance imaging in detecting deltoideal acromial enthesopathy: an early finding in the diagnosis of spondyloarthritis and an under-recognized cause of posterior shoulder pain

The acromial origin of the deltoid is a target structure of ankylosing spondylitis and related spondyloarthritis, which are often overlooked and underdiagnosed as causes of posterior shoulder pain. The objective of this article is to review the roles of sonography and magnetic resonance imaging in detecting deltoideal acromial enthesopathy and their importance for optimizing management in individuals with posterior shoulder pain. Adequate awareness of such enthesopathy as a potential manifestation of inflammatory rheumatic disorders is critical for early diagnosis of spondyloarthritis.

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.

Comparison of two ultrashort echo time sequences for the quantification of T1 within phantom and human Achilles tendon at 3 T

Ultrashort echo time (UTE) techniques enable direct imaging of musculoskeletal tissues with short T2 allowing measurement of T1 relaxation times. This article presents comparison of optimized 3D variable flip angle UTE (VFA-UTE) and 2D saturation recovery UTE (SR-UTE) sequences to quantify T1 in agar phantoms and human Achilles tendon. Achilles tendon T1 values for asymptomatic volunteers were compared to Achilles tendon T1 values calculated from patients with clinical diagnoses of spondyloarthritis (SpA) and Achilles tendinopathy using an optimized VFA-UTE sequence. T1 values from phantom data for VFA- and SR-UTE compare well against calculated T1 values from an assumed gold standard inversion recovery spin echo sequence. Mean T1 values in asymptomatic Achilles tendon were found to be 725±42 ms and 698±54 ms for SR- and VFA-UTE, respectively. The patient group mean T1 value for Achilles tendon was found to be 957±173 ms (P<0.05) using an optimized VFA-UTE sequence with pulse repetition time of 6 ms and flip angles 4, 19, and 24°, taking a total 9 min acquisition time. The VFA-UTE technique appears clinically feasible for quantifying T1 in Achilles tendon. T1 measurements offer potential for detecting changes in Achilles tendon due to SpA without need for intravenous contrast agents.

Imaging of the Achilles tendon in spondyloarthritis: a comparison of ultrasound and conventional, short and ultrashort echo time MRI with and without intravenous contrast

OBJECTIVES

To compare conventional MRI, ultrashort echo time MRI and ultrasound for assessing the extent of tendon abnormalities in spondyloarthritis.

METHODS

25 patients with spondyloarthritis and Achilles symptoms were studied with MRI and ultrasound. MR images of the Achilles tendon were acquired using T1-weighted spin echo, gradient echo and ultrashort echo time (UTE) sequences with echo times (TE) between 0.07 and 16 ms, before and after intravenous contrast medium. Greyscale and power Doppler ultrasound were also performed. The craniocaudal extent of imaging abnormalities measured by a consultant musculoskeletal radiologist was compared between the different techniques.

RESULTS

Abnormalities were most extensive on spoiled gradient echo images with TE = 2 ms. Contrast enhancement after intravenous gadolinium was greatest on the UTE images (TE = 0.07 ms). Fewer abnormalities were demonstrated using unenhanced UTE. Abnormalities were more extensive on MRI than ultrasound. Contrast enhancement was more extensive than power Doppler signal.

CONCLUSIONS

3D spoiled gradient echo images with an echo time of 2 ms demonstrate more extensive tendon abnormalities than the other techniques in spondyloarthritis. Abnormalities of vascularity are best demonstrated on enhanced ultrashort echo time images.

Pelvic MRI findings of juvenile-onset ankylosing spondylitis

Ankylosing spondylitis (AS) is the most common clinical subgroup of sero-negative spondyloarthropathies. Radiographic and clinical signs of bilateral inflammatory involvement of sacroiliac joints are the gold standard for the diagnosis of juvenile AS. Although radiographic evidence of sacroiliitis is included in the definition, it is not mandatory for the diagnosis of juvenile AS. The aim of this study is to describe pelvic enthesitis-osteitis MRI findings accompanying sacroiliitis in a group of juvenile AS. Eleven patients suffering from low back pain underwent MRI of the pelvis and were enrolled in this retrospective study. The mean duration of symptoms was 12 months. The mean age of the 11 cases in our study was 12.18 years (range, 6-19). There were eight boys and three girls. Anteroposterior radiographs of the pelvis were obtained in all patients. Sacroiliac joint involvement was detected in all of the cases by pelvic MRI. Pathologic signal changes were detected in the pubic symphisis (osteitis pubis) in ten cases, trochanteric bursitis in six cases, coxofemoral joint in five cases, crista iliaca in three cases, and ischion pubis in three cases. There was increased T2 signal intensity in eight of the 11 cases (72.7%) relevant with soft tissue edema/inflammation. This high correlation between sacroiliitis and enthesitis suggests that enthesitis could be an important finding in juvenile AS.

[Cross-sectional imaging of peripheral involvement in ankylosing spondylitis]

Ankylosing spondylitis is the most common spondyloarthropathy. It is characterized by enthesopathy (inflammation at the insertion of ligaments, tendons or fascia to bone). The os calcis is most frequently involved. Additional peripheral manifestations include synovitis and dactylitis. Unlike radiographs that demonstrate late manifestations of the disease, ultrasound and MRI demonstrate early inflammatory changes of bones and soft tissues. Multiple sites of involvement may also be detected on a single examination. Both imaging modalities facilitate early diagnosis, a crucial element for patient management. Both modalities may also monitor lesion regression during treatment.

Imaging of seronegative spondyloarthritis

Magnetic resonance imaging (MRI) and ultrasonography (US) are useful adjuncts in the diagnosis of seronegative spondyloarthritides (SpA); a group of diseases that present early at a stage when radiographic assessment is invariably normal. This chapter will review how MRI and US can be used in the evaluation of early SpA. The diffuse osteitis/enthesitis on MRI may serve as a diagnostic hallmark for SpA spinal disease, but needs confirmatory studies for comparison with other spinal pathologies. MRI is the modality of choice for monitoring axial disease in anti-tumour necrosis factor (TNF) therapy responses in the research environment, but it is not yet certain whether this will be relevant in clinical practice. Anti-TNF therapy may be associated with regression of MRI-determined osteitis, but retardation of associated bony fusion is debatable. MRI and US are still undergoing evaluation for the diagnosis of enthesitis of the appendicular skeleton; US, in particular, shows promise at these sites.

Achilles tendon problems: not just an orthopaedic issue

PURPOSE

To review the current concepts on Achilles tendon involvement in various pathological conditions.

METHOD

A literature search was conducted to trace relevant literature on Achilles tendon problems in general pathologies.

RESULTS

The Achilles tendon can be involved in inflammatory and autoimmune conditions, genetically determined collagen abnormalities, infectious diseases, tumours, and neurological conditions which are not of a primary surgical nature.

CONCLUSIONS

Although Achilles tendon problems are classically considered frequent in active individuals from overuse or a single acute episode, problems in the Achilles tendon can be a consequence of several conditions.

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.

MRI of enthesitis of the appendicular skeleton in spondyloarthritis

Entheses are sites where tendons, ligaments, joint capsules or fascia attach to bone. Inflammation of the entheses (enthesitis) is a well-known hallmark of spondyloarthritis (SpA). As entheses are associated with adjacent, functionally related structures, the concepts of an enthesis organ and functional entheses have been proposed. This is important in interpreting imaging findings in entheseal-related diseases. Conventional radiographs and CT are able to depict the chronic changes associated with enthesitis but are of very limited use in early disease. In contrast, MRI is sensitive for detecting early signs of enthesitis and can evaluate both soft-tissue changes and intraosseous abnormalities of active enthesitis. It is therefore useful for the early diagnosis of enthesitis-related arthropathies and monitoring therapy. Current knowledge and typical MRI features of the most commonly involved entheses of the appendicular skeleton in patients with SpA are reviewed. The MRI appearances of inflammatory and degenerative enthesopathy are described. New options for imaging enthesitis, including whole-body MRI and high-resolution microscopy MRI, are briefly discussed.

Bone marrow changes on STIR MR images of asymptomatic feet and ankles

The purpose of this study was to evaluate the prevalence, pattern and size of bone marrow changes on short-tau inversion recovery (STIR) magnetic resonance (MR) images of asymptomatic feet and ankles. In 78 asymptomatic volunteers (41 women, 37 men; median age 47 years; range 23-83 years) sagittal STIR MR images of hindfoot and midfoot were reviewed for various patterns of high signal changes in bone marrow. The size of these bone marrow changes was measured, and signal intensity was rated semi-quantitatively using a scale from 0 (=normal) to 10 (=fluid-like). Fifty percent (39/78) of all volunteers had at least one bone marrow change. Thirty-six percent (28/78) of all volunteers had edema-like changes, 26% (20/78) had necrosis-like changes, and 5% (4/78) had cyst-like changes. The long diameters of all changes varied between 4 mm and 16 mm (median 7.5 mm). The median signal intensity for all changes was 5.0 (range 1-10). Bone marrow changes on STIR MR images are commonly detected in asymptomatic feet and ankles. However, such changes tend to be small (<1 cm) or subtle.

Magnetic resonance imaging of hindfoot involvement in patients with spondyloarthritides: comparison of low-field and high-field strength units

OBJECTIVE

To compare MRI evaluation of a painful hindfoot of patients with spondyloarthritides (SpA) on low-field (0.2 T) versus high-field (1.5 T) MRI.

MATERIALS AND METHODS

Patients with SpA and hindfoot pain were randomly referred to either high-field or low-field MRI. Twenty-seven patients were evaluated (male/female: 17:10; mean age: 39+/-1.4 years). Fifteen patients were examined by low-field and 12 by high-field MRI. Two patients (evaluated by high-field MRI) were excluded. Images were separately read by two radiologists who later reached a consensus. In each patient the prevalence of erosions, fluid, synovitis or bone marrow edema of the hindfoot joints, tendinosis or tenosynovitis of tendons, enthesitis of the plantar fascia and Achilles tendon and retrocalcaneal bursitis were recorded. Clinical and demographic parameters were comparable between both groups.

RESULTS

MRI evaluation of joints and tendons of the hindfoot revealed no significant differences in patients with SpA groups for all parameters. Analyzing all joints or tendons together, there was no statistically significant difference between the two groups.

CONCLUSION

Low-field and high-field MRI provide comparable information for evaluation of inflammatory hindfoot involvement. Thus, low-field MRI can be considered as a reliable diagnostic tool for the detection of hindfoot abnormalities in SpA patients.

Pharmacogenetic of antirheumatic treatments: clinical implications

Preliminary pharmacogenetic data suggest that germline genetic informations might be of value in individualizing disease-modifying antirheumatic drugs (DMARDs) therapy in various autoimmune chronic inflammatory diseases. Either DMARDs small molecules (DMARDs-SM) or DMARDs biological therapies (DMARDs-BT) might be selected for their lower toxicity or better efficacy based on single-nucleotide polymorphisms (SNPs) of genes governing the metabolism of drugs, or the response of immune cells to proinflammatory molecules, or the proinflammatory molecular activity of immune cells. Data available for one DMARDs-SM, methotrexate, suggest that a careful assessment of the SNPs of four enzymes involved in the folate metabolism allow one to construct a genetic index of toxicity (toxicogenetic index) that might be employed in daily practice to find the patient's most at risk. Only the full knowledge of the various gene polymorphisms controlling the phenotypic manifestations of the inflammatory-immunological milieu of each rheumatic disease will allow one to obtain the clear definition of a personalized medicine. Few different cytokine gene SNPs seem to be of importance in determining the susceptibility to diseases, or the aggressiveness of diseases. The role of genetics in affecting a possible clinical response to DMARDs-BT targeting specific inflammatory molecules or their receptors still has to be defined. However, the available data suggest that cytokine (and/or receptors) gene SNPs might indeed play a role in determining the biological effects, hence the clinical effectiveness of DMARDs-BT. Crucial to this aim will be the prospective analysis of clinical benefits and safety on the basis of the at baseline stratification of gene SNPs in each chronic inflammatory rheumatic disease before starting any new DMARDs-SM or DMARDs-BT.

Clinical utility of sonography in diagnosing plantar fasciitis

OBJECTIVE

The purpose of this study was to investigate the efficacy of sonography in the detection of plantar fasciitis (PF) compared with magnetic resonance imaging (MRI) findings in subjects with inferior heel pain.

METHODS

Seventy-seven patients with unilateral (n = 9) and bilateral (n = 68) heel pain were studied. Seventy-seven age- and sex-matched asymptomatic subjects served as a control group. Magnetic resonance imaging was used to establish a diagnosis of PF with sagittal T1-weighted, T2-weighted, and short tau inversion recovery sequences. The sonographic appearances of PF were compared with MRI findings. Plantar fascia and heel pad thickness were also measured on both imaging modalities.

RESULTS

Compared with MRI, sonography showed 80% sensitivity and 88.5% specificity in assessing PF. A strong correlation was found between plantar fascia and fat pad thickness measurements done by sonography (P < .001; r = 0.854) and MRI (P < .001; r = 0.798). Compared with the asymptomatic volunteers, patients with PF had significant increases in plantar fascia and heel pad thicknesses, weight, and body mass index (P = .0001). Heel pad thickness was also significantly increased with pain duration (P = .021).

CONCLUSIONS

Although MRI is the modality of choice in the morphologic assessment of different plantar fascia lesions, sonography can also serve as an effective tool and may substitute MRI in the diagnosis of PF.