Periosteal Manifestations of Osteomyelitis and Arthritis on Ultrasound: A Systematic Review.

Ultrasound (US) can visualize the periosteal changes in the early stage compared to radiography. In this review, we studied periosteal manifestations on US and assessed their diagnostic utility for osteomyelitis (OM) and arthritis. We included articles that studied ultrasonographic findings of periosteal changes in OM and arthropathies with aims to systematically review periosteal manifestations of each condition and summarize diagnostic values of each finding. A total of 13 articles were included in the systematic review. Of these, 10 articles are on OM, 3 articles are on psoriatic arthritis (PsA), 1 article is on rheumatoid arthritis (RA), and 1 article is on gouty arthritis (GA). In OM, subperiosteal fluid/subperiosteal collection (SF/SC) was detected in 32%-76% within 72 h after presentation. Periosteal reaction (PR) was seen after day 4 and the sensitivity on US ranges from 33% to 100%. In PsA, PR was seen near 16%-59% in active PsA joints. Periosteal changes are rarely detected in RA joints. Small hyperechoic spots were seen in 87.5% of GA. SF/SC may be seen on US as the earliest sign followed by PR for OM. PR is more specific in PsA than RA. Further investigations on periosteal abnormalities on US are warranted to confirm our findings.

Ultrasound evaluation of the Achilles enthesis in inflammatory and non-inflammatory processes: a systematic review and meta-analysis.

OBJECTIVES: Ultrasound evaluation of the Achilles tendon has been utilised to assess involvement at the entheses in the setting of various inflammatory, metabolic, and mechanical processes. The purpose of this systematic review was to evaluate the differences in ultrasound findings at the Achilles enthesis between inflammatory tendinopathy (IT) versus non-inflammatory tendinopathy (NIT). METHODS: A review of all studies involving ultrasound evaluation of IT or NIT (mechanical or metabolic) affecting the Achilles enthesis was performed by searching the Embase, PubMed and Medline databases from start until October 2020. We assessed study quality and extracted summary data from each individual study. We used random-effects meta-analysis to determine the average proportion of affected anatomic sites across all studies for each abnormality, weighting the analysis based on the size of each individual study. RESULTS: Achilles enthesis thickening was more frequent in the symptomatic IT (sIT) group (37.8%) compared to the unspecified IT (25%), NIT (11.2%) and healthy control (2.7%) groups. Increased vascularity at the enthesis was more common in the NIT (23.4%) group compared to the IT (9%), sIT (8.6%) and healthy control (0.1%) groups. Erosions were more common among the IT (17.3%) and sIT (14%) groups compared to the NIT (2.2%) and healthy controls (0.3%) groups. CONCLUSIONS: While Achilles enthesis thickening, Doppler signal and calcaneal erosions discriminate IT from healthy subjects, erosions are more likely to distinguish IT from NIT than thickening or Doppler signal. Additional study is needed to quantify the diagnostic performance of ultrasound at this location given the frequency of abnormalities in NIT.

North American musculoskeletal ultrasound scanning protocol of the shoulder, elbow, wrist, and hand: update of a Delphi Consensus Study.

INTRODUCTION/OBJECTIVES: There has been an increase in the proficiency and utilization of ultrasound among North American rheumatologists over the past decade. This study aims to create an updated upper extremity scanning protocol to inform ultrasound curriculum development for the American College of Rheumatology affiliated fellowship programs and guide clinical practice patterns in North America. METHOD: Three Delphi survey rounds were used to reach consensus on tiered-mastery designations for scan views of the shoulder, elbow, wrist, and hand joints. The survey was disseminated by Qualtrics™ to 101 potential participants with ultrasound experience. High agreement was defined as having ≥ 85% consensus and final tier designation as > 50% agreement for a preferred tier. Changes in responses were evaluated by McNemar's chi-square test. RESULTS: Consensus was achieved for 70% of scan views of the upper extremity joints. Two views-ulnar transverse view of the wrist and the radial/ulnar orthogonal views over metacarpophalangeal joints 2 and 5 of the hand-were upgraded from tier 2 to tier 1. The suprascapular transverse and the axillary longitudinal views of the shoulder were downgraded from tier 2 to tier 3. A new anterior transverse view of the elbow was added to the protocol with tier 1 designation. CONCLUSIONS: This study reflects the current opinions of North American rheumatologists for scanning upper extremity joints and provides support for the updated protocol and guidance for educators in rheumatology ultrasound. Key Points • Ultrasound scan views of the metacarpophalangeal, wrist, elbow, and glenohumeral joint recesses and views of the biceps and rotator cuff tendons at the shoulder were perceived as essential views of the upper extremity scanning protocol for rheumatologists to master and perform routinely. • A targeted scanning approach of the upper extremity joints may be considered when focal symptoms are present. • The North American Musculoskeletal Ultrasound Scanning Protocol shares some similarities with existing musculoskeletal ultrasound protocols of other specialties and worldwide rheumatology societies but varies in the extent of examination and emphasis on certain specialty-specific focuses.

North American musculoskeletal ultrasound scanning protocol of the hip, knee, ankle, and foot: update of a Delphi consensus study.

BACKGROUND/OBJECTIVE: A North American rheumatology consensus on tiered-mastery designation for anatomic views was developed in 2011 for course and fellowship teaching. This study updates the lower extremity joint scanning protocols aiming to inform musculoskeletal ultrasound curriculum development for the American College of Rheumatology affiliated Fellowship Programs. METHODS: Three Delphi rounds were conducted to reach consensus for tiered-level mastery designation for hip, knee, ankle, and foot scanning views. The survey was disseminated (Qualtrics™) to 101 potential participants with ultrasound teaching experience. High agreement was defined as ≥ 85% consensus and final tier designation as having >50% agreement for the preferred tier. Response changes were evaluated by McNemar's chi-square test. RESULTS: Consensus regarding tier designations was reached for 80% of the views. Three knee views (anterior transverse suprapatellar, medial, and lateral longitudinal) and 2 ankle views (anterior and posterior transverse) achieved upgrades to tier 1 from 2. The transverse sacroiliac hip joint was downgraded from tier 2 to 3. The lateral longitudinal hip view was added with a tier 1 designation. CONCLUSION: Updated scanning protocols support modifications reflecting current scanning methods delivered by North American rheumatologists performing point of care ultrasound that may inform educators involved in rheumatology ultrasound. Key Points • The anterior transverse suprapatellar, medial, and lateral longitudinal knee views; the anterior and posterior transverse ankle views; and the lateral longitudinal view hip view were perceived as important to master and perform routinely. • The transverse sacroiliac joint view was suggested to be performed based on practice focus.

Heel fat pad involvement in rheumatoid arthritis: a review and case series.

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease affecting not only the synovial joints but also multiple extra-articular sites, including ankle and foot soft tissue. Hindfoot abnormalities usually follow those in the forefoot, with up to 4 out of 10 patients experiencing talalgia during their disease course. Enthesophytosis, retrocalcaneal bursitis, and plantar fasciitis are among the most common etiologies, while heel fat pad abnormalities like subcalcaneal bursitis are rare. Here, we report two cases of subcalcaneal bursitis, and the first case of heel fat pad and subcalcaneal bursa herniation in patients with established RA, along with a comprehensive literature review of subcalcaneal bursitis and other heel fat pad abnormalities in RA. Subcalcaneal bursitis, also referred to as panniculitis, inflammatory-edematous lesion, or adventitial (adventitious) bursitis has been reported in up to 10% of patients with RA. It appears as a compressible, heterogeneous, and hypoechoic subcalcaneal mass on ultrasound (US), with peripheral vascularization on Doppler US. Patients may present with heel discomfort. Ultrasonographic assessment is usually sufficient to confirm the presence of heel fat pad pathologies. Rest, analgesics, and mechanical aids with or without addition of disease-modifying antirheumatic drugs are usually employed, while intervention is rarely required.

Dynamic changes in the infrapatellar knee structures with quadriceps muscle contraction. An in vivo study.

OBJECTIVE: To determine the effect of knee flexion and submaximal isometric quadriceps muscle (Q) contraction on the patellar tendon (PT), the infrapatellar fat pad (IPFP), and the deep infrapatellar bursa (IPB) from extension to full flexion. METHODS: In Study 1, the dominant knee of seven healthy subjects was studied in full extension and at 60° flexion during relaxation and Q contraction. Each knee was inspected and palpated, the transverse infrapatellar diameter was measured by plicometry, and measurements of the anteroposterior (AP) thickness of the IPFP were made by ultrasound (US). In Study 2, the dominant knee of seven healthy subjects was studied by US in full flexion, and then, at 15° decrements, down to 60° flexion during relaxation and Q contraction. Both studies had IRB approval. Results were analyzed with the Wilcoxon test and descriptive statistics. RESULTS: In Study 1, Q contraction caused straightening of the patellar tendon (PT), a statistically significant widening of the IPFP by plicometry, and an increased AP thickness of the IPFP by US, in both knee positions. In Study 2, in full knee flexion, the PT contacted the tibial cortex in all seven subjects. Upon increasing extension, the PT-tibial cortex contact was lost in all subjects nearing 90° flexion. The contraction of the Q made the concave PT straight, grew the width of the underlying IPFP, and the apron of the IPFP moved distally within the IPB in all knee positions. A small amount of bursal fluid was present in all seven subjects. CONCLUSION: Q contraction makes the IPFP bulge anteriorly, on both sides of the PT, and distally into the IPB, with possible biomechanical implications. In full knee flexion, the PT contacted the tibia, confirming a fulcrum at this site.

Consensus-based semi-quantitative ultrasound scoring system for gout lesions: Results of an OMERACT Delphi process and web-reliability exercise.

OBJECTIVE: This study aimed to develop (1) a new ultrasound definition for aggregates and (2) a semi-quantitative ultrasound scoring system (0-3) for tophus, double contour and aggregates. Furthermore, the intra- and inter-reader reliabilities of both the re-defined aggregates and the semi-quantitative scoring system were assessed using static image exercises. METHODS: Thirty-seven rheumatologists were invited. A Delphi process was used for re-defining aggregates and for selecting a semi-quantitative scoring system with >75% agreement obligate for reaching consensus. Subsequently, a web-based exercise on static ultrasound images was conducted in order to assess the reliability of both the re-defined aggregates and the semi-quantitative scoring system. RESULTS: Twenty rheumatologists contributed to all rounds of the Delphi and image exercises. A consensual re-definition of aggregates was obtained after three Delphi rounds but needed an overarching principle for scoring aggregates in patients. A consensus-based semi-quantitative ultrasound scoring system for gout lesions was developed after two Delphi rounds. The re-definition of aggregates showed good intra- and inter-reader reliability (κ-values 0.71 and 0.61). The reliabilities of the scoring system were good for all lesions with slightly higher intra-reader (κ-values 0.74-0.80) than inter-reader reliabilities (κ-values 0.61-0.67). CONCLUSION: A re-definition of aggregates was obtained with a good reliability when assessing static images. The first consensus-based semi-quantitative ultrasound scoring system for gout-specific lesions was developed with good inter- and intra-reader reliability for all lesions when tested in static images. The next step is to assess the reliabilities when scoring lesions in patients.

The Effect of IL-6 Inhibitors on Mortality Among Hospitalized COVID-19 Patients: A Multicenter Study.

BACKGROUND: The effectiveness of interleukin-6 inhibitors (IL-6i) in ameliorating coronavirus disease 2019 (COVID-19) remains uncertain. METHODS: We analyzed data for patients aged ≥18 years admitted with a positive severe acute respiratory syndrome coronavirus 2 polymerase chain reaction test at 4 safety-net hospital systems with diverse populations and high rates of medical comorbidities in 3 US regions. We used inverse probability of treatment weighting via machine learning for confounding adjustment by demographics, comorbidities, and disease severity markers. We estimated the average treatment effect, the odds of IL-6i effect on in-hospital mortality from COVID-19, using a logistic marginal structural model. RESULTS: Of 516 patients, 104 (20.1%) received IL-6i. Estimate of the average treatment effect adjusted for confounders suggested a 37% reduction in odds of in-hospital mortality in those who received IL-6i compared with those who did not, although the confidence interval included the null value of 1 (odds ratio = 0.63; 95% confidence interval, .29-1.38). A sensitivity analysis suggested that potential unmeasured confounding would require a minimum odds ratio of 2.55 to nullify our estimated IL-6i effect size. CONCLUSIONS: Despite low precision, our findings suggested a relatively large effect size of IL-6i in reducing the odds of COVID-19-related in-hospital mortality.

Scruples over Speckles.

The "snowstorm" sign refers to the ultrasound appearance of motile hyperechoic specks within synovial fluid and has been reported to have a high specificity for gout. We describe three additional etiologies commonly encountered in the rheumatology clinic that can produce a snowstorm: calcium pyrophosphate deposition disease, fibrin collections/rice bodies, and gas bubbles in viscous synovial fluid.

Sonographic Features of Salivary Glands in Sjögren's Syndrome and its Mimics.

PURPOSE OF REVIEW: For 30 years, ultrasound has been investigated as a means to evaluate salivary gland abnormalities in patients with autoimmune disease. We aim to review the test characteristics of ultrasound for diagnosing Sjögren's syndrome, the scoring systems used for this purpose, and the ultrasound similarities and differences between Sjögren's syndrome and some of its potential salivary gland mimics. RECENT FINDINGS: Hypo/anechoic glandular lesions are the major ultrasound characteristic found in Sjögren's syndrome. Most studies have reported such ultrasound abnormalities to have a sensitivity and specificity in the range of 65-85% and 85-95%, respectively, as well as a positive likelihood ratio between 4 and 12. However, similar findings can also be seen in sarcoidosis, amyloidosis, IgG4-related disease, HIV, and lymphoma. A "nodal" pattern of involvement or the ultrasound artifact of "through transmission" can help distinguish some of these mimics from Sjogren's syndrome. Ultrasound can substantially influence the diagnosis of Sjögren's syndrome.

Ultrasound Doppler and tenosynovial fluid analysis in tenosynovitis.

OBJECTIVE: To assess Doppler ultrasound (US) and tenosynovial fluid (TSF) characteristics in tenosynovitis within common rheumatic conditions, as well as their diagnostic utility. METHODS: Subjects with tenosynovitis underwent Doppler US and US-guided TSF aspiration for white cell count (WCC) and crystal analysis. Tenosynovial Doppler scores (DS) were semiquantitatively graded. TSF WCC and DS were compared using Kruskal-Wallis tests and logistic regression between non-inflammatory conditions (NIC), inflammatory conditions (IC) and crystal-related conditions (CRC). Receiver operating curves, sensitivity and specificity assessed the ability of WCC and DS to discriminate IC from NIC. RESULTS: We analysed 100 subjects from 14 sites. The mean age was 62 years, 65% were female, and the mean TSF volume was 1.2 mL. Doppler signal was present in 93.7% of the IC group and was more frequent in IC than in NIC group (OR 6.82, 95% CI 1.41 to 32.97). The TSF median WCC per 109/L was significantly higher in the IC (2.58, p<0.001) and CRC (1.07, p<0.01) groups versus the NIC group (0.38). A TSF cut-off of ≥0.67 WCC per 109/L optimally discriminated IC versus NIC with a sensitivity and specificity each of 81.3%. In the IC group, 20 of 48 (41.7%) subjects had a TSF WCC <2.00 per 109/L. CONCLUSIONS: A negative DS helps rule out IC in tenosynovitis, but a positive DS is non-specific and merits TSF testing. Unlike synovial fluid, a lower TSF WCC better discriminates IC from NIC. US guidance facilitates aspiration of minute TSF volume, which is critical for diagnosing tenosynovial CRC.

Comparison of Ultrasound Features of Major Salivary Glands in Sarcoidosis, Amyloidosis, and Sjögren's Syndrome.

OBJECTIVE: While salivary gland ultrasound (SGU) has gained prominence for evaluating Sjögren's syndrome, little information exists on SGU appearance of sarcoidosis and amyloidosis, potential mimics of Sjögren's syndrome. Our goal in this study was to estimate the diagnostic accuracy of major SGU features in differentiating Sjögren's syndrome from sarcoidosis, amyloidosis, and controls. METHODS: We enrolled consecutive adult ambulatory patients with a clinical diagnosis of Sjögren's syndrome fulfilling the 2016 American College of Rheumatology (ACR) classification criteria; we also enrolled patients with a clinical diagnosis of sarcoidosis or systemic immunoglobulin light chain (AL) amyloidosis, with histologic confirmation from any tissue, and rheumatology outpatients without diagnoses affecting salivary glands. Subjects underwent major SGU using the Hocevar protocol, with resulting video clips reviewed blind to clinical diagnosis. RESULTS: Sjögren's syndrome SGU scores were greater than in patients from the other groups, but there were no distinguishing salivary gland features from AL amyloidosis or sarcoidosis. None of the patients in the control group scored higher than 17, a cutoff previously suggested for Sjögren's syndrome, but 27% of patients with AL amyloidosis and 19% with sarcoidosis scored higher than 17. Adding Hocevar SGU scores of ≥17 to the 2016 ACR/European League Against Rheumatism criteria in a parallel scheme increased the sensitivity for Sjögren's syndrome from 87% to 98%, while combining the 2 criteria in series increased specificity from 81% to 98%. CONCLUSION: Sjögren's syndrome, sarcoidosis, and AL amyloidosis share common SGU features that can help distinguish these conditions from patients without systemic rheumatologic disease. Clinicians should carefully consider these potential mimics when interpreting salivary gland US results.

Musculoskeletal Ultrasound Scanning Protocol Consensus Statements on Scanning Conventions and Documentation in the US.

OBJECTIVE: European rheumatology and radiology-determined standards have largely driven the execution of ultrasound in rheumatology (RhUS). How this translates to American rheumatologic practice has not been examined. A rheumatology-driven consensus on documentation, scanning conventions, and tiered-mastery designation for anatomic region views was developed in 2011 and served as the framework for training and clinical research validation. The present study was undertaken to update this consensus to reflect current utilization of musculoskeletal RhUS evaluation in the US. METHODS: A 3-round Delphi method study was conducted using a 96-item questionnaire sent via Qualtrics survey software to 101 respondents experienced in RhUS education and scholarship. The target participant number was 38. High agreement was defined as ≥85% agreement on each item. McNemar's chi-square test was used to analyze changes in agreement in the responses. Comments were reviewed for content analysis. RESULTS: A total of 46 respondents completed all 3 rounds. Of documentation and scanning convention statements, 80% and 100%, respectively, reached high agreement. Comments reflected the need for rheumatology-defined and disease-specific complete scan and limited scan definitions, separate from radiology-defined definitions. CONCLUSION: Many scanning conventions from 2011 remain relevant in current practice. There is a need to determine rheumatology-defined descriptions for common procedural terminology codes for complete and limited scans that accurately reflect the current state of RhUS.

Musculoskeletal Ultrasound Instruction in Adult Rheumatology Fellowship Programs.

OBJECTIVE: Musculoskeletal ultrasound (MSUS) in rheumatology in the US has advanced by way of promotion of certifications and standards of use and inclusion of core fellowship curriculum. In order to inform endeavors for curricular integration, the objectives of the present study were to assess current program needs for curricular incorporation and the teaching methods that are being employed. METHODS: A needs-assessment survey (S1) was sent to 113 rheumatology fellowship program directors. For programs that taught MSUS, a curriculum survey (S2) was sent to lead faculty. Programs were stratified according to program size and use of a formal written curriculum. RESULTS: S1 (108 of 113 respondents; response rate 96%) revealed that 94% of programs taught MSUS, with 41% having a curriculum. Curricular implementation was unaffected by program size. Formal curricular adoption of MSUS was favored by 103 directors (95.3%), with 65.7% preferring such adoption to be optional. S2 (74 of 101 respondents; response rate 73%) showed that 41% of programs utilized a formal curriculum. Multiple teaching strategies were used, with content that was generally similar. Use of external courses, including the Ultrasound School of North American Rheumatologists course, was prevalent. Fewer barriers were noted compared to past surveys, but inadequate time, funding, and number of trained faculty still remained. Lack of divisional interest (P = 0.046) and interest of fellows (P = 0.012) were noted among programs without a formal curriculum. CONCLUSION: MSUS is taught by a significantly larger number of rheumatology fellowship programs today. Multiple teaching strategies are used with common content, and barriers still remain for some programs. Most program directors favor inclusion of a standardized MSUS curriculum, with many favoring inclusion to be optional.

Modern Landscapes and Strategies for Learning Ultrasound in Rheumatology.

Ultrasound in rheumatology is gaining increasing acceptance in the field, with its use expanding beyond the musculoskeletal system to image rheumatic disease pathology of the vasculature, salivary glands, and lungs. Fellows in training and practicing clinicians are seeking ways to attain training and competency assessment. These standards are evolving, but no uniform mechanism for training exists. Although clinicians in practice find a wide array of resources available for self-directed education in ultrasound in rheumatology, a consensus-based and publicly available training curriculum can further enhance and standardize learning. This article discusses ultrasound in rheumatology education opportunities, competency assessment, and certification pathways.

Basic Calcium Phosphate Crystal Periarthritis Involving the Distal Interphalangeal Joints in a Patient with Systemic Lupus Erythematosus.

BACKGROUND Increased serum levels of basic calcium phosphate (BCP) and calcium pyrophosphate (CPP) are found in patients on dialysis, following trauma, and are associated with connective tissue diseases (CTDs), including dermatomyositis, scleroderma, and systemic lupus erythematosus (SLE). The shoulder is the joint most commonly associated with BCP crystal periarthritis. A report is presented of a case of BCP crystal periarthritis involving the distal interphalangeal (DIP) joints in a patient with SLE. CASE REPORT A 34-year-old woman with SLE presented with destructive arthritis of the DIP joints that developed during a two-year period, despite immunosuppressive therapy. Aspiration of synovial fluid from a DIP joint showed a lack of inflammatory cells, but the fluid was positive for the presence of crystals on alizarin red S histochemical staining. CONCLUSIONS A case of BCP crystal periarthritis is reported in a patient with SLE with chronic joint symptoms that were unresponsive to immunosuppressive therapy. This case has shown that chronic joint symptoms that are unresponsive to immunosuppressive therapy may be due to causes other than connective tissue disease (CTD) and that imaging studies and diagnostic workup that includes synovial fluid examination may support the diagnosis of BCP crystal periarthritis.

A Vascular Obstacle in Ultrasound-Guided Hip Joint Injection.

BACKGROUND: We evaluated the risk of lateral circumflex femoral artery (LCFA) injury during ultrasound-guided intra-articular hip injections. METHODS: This study was divided into three parts. (1) Four ultrasound-guided hip injections were performed on human cadavers. With needles in place, tissues were dissected to expose the LCFA. (2) Ultrasound-trained rheumatologists marked a planned needle trajectory from skin to hip joint on live human ultrasound images during an Observed Structured Clinical Examination (OSCE). Doppler was subsequently activated to locate the LCFA, and the distance between trajectory and arterial signal was recorded. (3) Rheumatologists certified in musculoskeletal ultrasound were surveyed about joint injection vascular complications. RESULTS: (1) In one of the four cadaveric dissections, the needle made direct contact with the LCFA. (2) Of 27 OSCE participants, only two activated Doppler before marking simulated hip injection trajectories. Trajectories passed through LCFA Doppler signal in six (22%) cases. Mean minimal distance from trajectory to arterial signal was 4 mm (range, 0-11 mm). (3) Of 62 survey respondents, 24% stated that they did not use Doppler routinely. While none reported bleeding injuries with their patients, 16% knew of a hip injection-related vascular complication performed by another provider. CONCLUSION: There is a risk of LCFA injury during ultrasound-guided hip joint injection. Routine use of Doppler should be considered in standard hip injection protocols.

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.