Digital artery flow hemodynamics: An ultrasonographic study.

BACKGROUND: There is a lack of data regarding the baseline hemodynamic blood flow parameters of the wrist and digits. Therefore, we aimed to quantify the digital and radial artery blood flow parameters using ultrasound and assess the influence of patient characteristics on hemodynamics. METHODS: We analyzed ultrasonographic data from 25 patients (50 hands) between October 2019 and December 2021. Variables of interest included dimensions of the radial artery and index finger (IF) ulnar and radial digital arteries at the palmodigital crease and their corresponding flow parameters. We compared variables among men and women and patients with and without diabetes using Wilcoxon Rank Sum test. RESULTS: Our cohort consisted of 18 women (36 hands) and three participants with diabetes (six hands). The mean diameter of the IF radial digital artery was 7 mm, and that of the ulnar digital artery was 10 mm. The average peak systolic velocity for the radial digital artery was 21.31 cm/sec, and for the ulnar digital artery, it was 30.03 cm/sec. Comparing men and women, the only significant difference found was in the time-averaged mean velocity for the ulnar digital artery (men:5.66 cm/sec vs. women:9.68 cm/sec, P = 0.02) and volume of flow for the ulnar digital artery (men:10.87cc/min vs. women:18.58cc/min, P = 0.03). We found no differences in blood flow parameters comparing participants with and without diabetes. CONCLUSION: These data provide a baseline measurement of digital flow hemodynamics that can be used in future studies to model vascular flow after replantation.

Clinical Applications, Challenges, and Recommendations for Artificial Intelligence in Musculoskeletal and Soft-Tissue Ultrasound: AJR Expert Panel Narrative Review.

Artificial intelligence (AI) is increasingly used in clinical practice for musculoskeletal imaging tasks, such as disease diagnosis and image reconstruction. AI applications in musculoskeletal imaging have focused primarily on radiography, CT, and MRI. Although musculoskeletal ultrasound stands to benefit from AI in similar ways, such applications have been relatively underdeveloped. In comparison with other modalities, ultrasound has unique advantages and disadvantages that must be considered in AI algorithm development and clinical translation. Challenges in developing AI for musculoskeletal ultrasound involve both clinical aspects of image acquisition and practical limitations in image processing and annotation. Solutions from other radiology subspecialties (e.g., crowdsourced annotations coordinated by professional societies), along with use cases (most commonly rotator cuff tendon tears and palpable soft-tissue masses), can be applied to musculoskeletal ultrasound to help develop AI. To facilitate creation of high-quality imaging datasets for AI model development, technologists and radiologists should focus on increasing uniformity in musculoskeletal ultrasound performance and increasing annotations of images for specific anatomic regions. This Expert Panel Narrative Review summarizes available evidence regarding AI's potential utility in musculoskeletal ultrasound and challenges facing its development. Recommendations for future AI advancement and clinical translation in musculoskeletal ultrasound are discussed.

Diagnostic and Interventional US of the Wrist and Hand: Quadrant-based Approach.

Diagnostic and interventional US of the wrist and hand can be challenging due to the small size and superficial location of structures and various disorders that need to be considered. A quadrant-based approach (volar, ulnar, dorsal, and radial) provides a rational method for performing a focused examination and joint positioning during both diagnostic imaging and intervention. Volar wrist disorders primarily involve the median nerve and the digital flexor system comprised of the flexor tendons and pulleys. The ulnar nerve and extensor carpi ulnaris tendon are chiefly responsible for ulnar-sided wrist pain. The differential diagnosis for dorsal-sided symptoms typically involves the extensor tendon compartments and includes distal intersection syndrome, extensor pollicis longus tear, and digital extensor apparatus injury. The soft-tissue ganglion is the most common abnormality in the dorsal wrist, typically associated with wrist ligaments or joint capsule. Radial-sided pain may be secondary to de Quervain tenosynovitis and must be differentiated from the more proximal intersection syndrome. US is an important tool for assessing the ulnar collateral ligament of the first metacarpophalangeal joint of the thumb and differentiating between displaced and nondisplaced tears, thereby influencing management. Despite the complexity of the anatomy and potential pathologic features within the wrist, a focused quadrant-based examination can permit the sonologist to focus on the structures of relevance. In conjunction with a systematic approach, this can aid in precise and efficient diagnostic scanning and intervention of the wrist and hand. ©RSNA, 2023 Supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Dynamic musculoskeletal ultrasound: slipping rib, muscle hernia, snapping hip, and peroneal tendon pathology.

Dynamic musculoskeletal ultrasound is an important diagnostic tool that allows the practitioner to observe soft tissue structures over a range of motion and identify pathology not diagnosed on other modalities. Familiarity with this modality allows health care practitioners to appropriately refer patients for this type of examination. This article will review several indications for dynamic ultrasound imaging, including slipping rib, muscle hernia, snapping hip, and peroneal tendon pathology. The examination technique and expected findings for common pathology in each location are discussed.

Ultrasonography of Superficial Soft-Tissue Masses: Society of Radiologists in Ultrasound Consensus Conference Statement.

The Society of Radiologists in Ultrasound convened a panel of specialists from radiology, orthopedic surgery, and pathology to arrive at a consensus regarding the management of superficial soft-tissue masses imaged with US. The recommendations in this statement are based on analysis of current literature and common practice strategies. This statement reviews and illustrates the US features of common superficial soft-tissue lesions that may manifest as a soft-tissue mass and suggests guidelines for subsequent management.

Medial Meniscal Extrusion Evaluation With Weight-Bearing Ultrasound: Correlation With MR Imaging Findings and Reported Symptoms: Correlation With MR Imaging Findings and Reported Symptoms.

OBJECTIVES: To compare medial meniscal extrusion on weight-bearing ultrasound (US) with supine US and magnetic resonance (MR) imaging correlating with meniscal pathology and reported symptoms. METHODS: IRB approved study with informed consent. Patients obtaining routine knee MR imaging for suspected knee pathology were prospectively evaluated with supine and weight-bearing US of the medial meniscus. Meniscal extrusion was measured independently by two fellowship-trained musculoskeletal radiologists. Correlation was made to presence or absence of meniscal degeneration or tear on MR imaging, as well as reported symptoms. Statistical significance was calculated via intraclass correlation coefficient (ICC) and analysis of variance (ANOVA). RESULTS: Ninety-nine knees from 95 subjects (50 males, 45 females; mean age 45 ± 15 years) were included. Mean medial meniscal extrusion measured at US for a normal meniscus (n = 36) was 0.8 mm when supine, increasing to 1.6 mm on weight-bearing. Mean meniscal extrusion in subjects with mucoid degeneration (n = 20) and those with meniscal tears (n = 43) was 1.6 mm, increasing to 2.3 mm with weight bearing. Inter-reader reliability showed ICC values of 0.853 to 0.940. There was a significant difference in medial meniscal extrusion comparing subjects with a normal medial meniscus at magnetic resonance imaging (MRI) and subjects with either meniscal degeneration or tear. There was no significant difference in degree of meniscal extrusion between subjects with meniscal degeneration or tear. There was trend of worsening symptoms and increasing functional limitations moving from normal meniscus to meniscal degeneration to meniscal tear. CONCLUSIONS: A normal meniscus shows lesser mobility between supine and upright position, than a pathologic meniscus. Both mucoid degeneration and meniscal tear demonstrate extrusion in the supine position, which increases with weight-bearing position.

Recommended musculoskeletal and sports ultrasound terminology: a Delphi-based consensus statement.

The current lack of agreement regarding standardised terminology in musculoskeletal and sports ultrasound presents challenges in education, clinical practice and research. This consensus was developed to provide a reference to improve clarity and consistency in communication. A multidisciplinary expert panel was convened consisting of 18 members representing multiple specialty societies identified as key stakeholders in musculoskeletal and sports ultrasound. A Delphi process was used to reach consensus, which was defined as group level agreement of >80%. Content was organised into seven general topics including: (1) general definitions, (2) equipment and transducer manipulation, (3) anatomical and descriptive terminology, (4) pathology, (5) procedural terminology, (6) image labelling and (7) documentation. Terms and definitions which reached consensus agreement are presented herein. The historic use of multiple similar terms in the absence of precise definitions has led to confusion when conveying information between colleagues, patients and third-party payers. This multidisciplinary expert consensus addresses multiple areas of variability in diagnostic ultrasound imaging and ultrasound-guided procedures related to musculoskeletal and sports medicine.

Recommended Musculoskeletal and Sports Ultrasound Terminology: A Delphi-Based Consensus Statement.

OBJECTIVES: The current lack of agreement regarding standardized terminology in musculoskeletal and sports ultrasound presents challenges in education, clinical practice, and research. This consensus was developed to provide a reference to improve clarity and consistency in communication. METHODS: A multidisciplinary expert panel was convened consisting of 18 members representing multiple specialty societies identified as key stakeholders in musculoskeletal and sports ultrasound. A Delphi process was used to reach consensus which was defined as group level agreement >80%. RESULTS: Content was organized into seven general topics including: 1) General Definitions, 2) Equipment and Transducer Manipulation, 3) Anatomic and Descriptive Terminology, 4) Pathology, 5) Procedural Terminology, 6) Image Labeling, and 7) Documentation. Terms and definitions which reached consensus agreement are presented herein. CONCLUSIONS: The historic use of multiple similar terms in the absence of precise definitions has led to confusion when conveying information between colleagues, patients, and third-party payers. This multidisciplinary expert consensus addresses multiple areas of variability in diagnostic ultrasound imaging and ultrasound-guided procedures related to musculoskeletal and sports medicine.

Imaging Characteristics of the Proximal Lateral Collateral Ligament of the Knee: Findings on Ultrasound and MRI With Histologic Correlation.

OBJECTIVES: Determine prevalence of increased signal intensity of the lateral collateral ligament (LCL) of the knee on MRI and decreased echogenicity on ultrasound, and compare with cadaveric histologic evaluation. METHODS: After IRB approval of this prospective study with informed consent, patients having knee MRI were additionally evaluated with ultrasound. Signal intensities of LCL on MRI (low, intermediate, high), echogenicity at ultrasound (hyperechoic, hypoechoic, anechoic), and extent of findings were assessed. Descriptive statistics, Wilcoxon signed ranked test, and intraclass correlation coefficient (ICC) were calculated. Two cadaveric knees were imaged with MRI and ultrasound, including histologic LCL evaluation. RESULTS: Seventy-three subjects were included (39 males, 34 females; mean age 48 ± 14 years) with 77 knee examinations. On MRI, low, intermediate, and high signals were present in 21% (16/77), 75% (58/77), and 4% (3/77), respectively. On ultrasound, echogenicity was assessed as hyperechoic, hypoechoic, and anechoic in 62% (48/77), 38% (29/77), and 0% (0/77), respectively. Mean length of increased signal was 8.6 mm (±4.9) on MRI, and 6.5 mm (±4.8) on ultrasound. The ICC showed a good to excellent intermodality reliability (0.735-0.899) without statistically significant difference for interreader measurements (P = .163-.795). Histology evaluation showed transition of ligament fibers to fibrocartilage at its insertion with increased connective tissue mucin corresponding to MRI and ultrasound findings. CONCLUSIONS: Increased signal intensity of the proximal LCL on ultrasound and MRI is common and corresponds to normal connective tissue mucin.

MR imaging of the quadriceps femoris tendon: distal tear characterization and clinical significance of rupture types.

OBJECTIVE: To characterize quadriceps femoris tendon tears on magnetic resonance (MR) imaging regarding tear extent, location, and presence of bony avulsion. MATERIALS AND METHODS: IRB approval was obtained and informed consent was waived for this retrospective case series. Electronic medical records from all patients in our hospital system were searched for keywords: knee MR imaging, and quadriceps tendon rupture or tear. MRI studies were randomized and independently evaluated by two fellowship-trained musculoskeletal radiologists. MR imaging was used to characterize each individual quadriceps tendon as having tendinosis, tear (location, partial versus complete, size, and retraction distance), and bony avulsion. Knee radiographs were reviewed for presence or absence of bony avulsion. Descriptive statistics and inter-reader reliability (Cohen's Kappa and Wilcoxon-signed-rank test) were calculated. RESULTS: Fifty-two patients with 53 quadriceps tears were evaluated (45 males, 7 females; mean age: 51 ± 13 years). The vastus intermedius (VI) tendon more often incurred a partial rather than a complete tear (39.6% vs. 37.7%), while the rectus femoris (RF), vastus medialis (VM), and vastus lateralis (VL) incurred complete tears more commonly (64.2-66%). Subjects with bony avulsion on radiographs had higher-grade tears of the RF, VM, and VL tears (p = 0.020-0.043) but not the VI. Most tendons tore at or immediately proximal to the patella (84.8-93.6%). Gaps in retracted torn tendons measured between 2.3 and 2.7 cm. Inter-reader reliability was substantial to almost perfect (κ = 0.624-0.953). CONCLUSION: Quadriceps femoris tendon tears most commonly involve the RF or VL/VM layers usually in proximity to the patella. A bony avulsion correlates with a more extensive tear. KEY POINTS: • Quadriceps femoris tendon tears most commonly involve the rectus femoris or vastus lateralis/vastus medialis layers. • A rupture of the quadriceps femoris tendon usually occurs in proximity to the patella. • A bony avulsion of the patella correlates with a more extensive tear of the superficial and middle layers of the quadriceps tendon.

A Randomized Phase II Study of Androgen Deprivation Therapy with or without Palbociclib in RB-positive Metastatic Hormone-Sensitive Prostate Cancer.

PURPOSE: Palbociclib, a cyclin-dependent kinase (CDK) 4/6 inhibitor, blocks proliferation in a RB and cyclin D-dependent manner in preclinical prostate cancer models. We hypothesized that cotargeting androgen receptor and cell cycle with palbociclib would improve outcomes in patients with metastatic hormone-sensitive prostate cancer (mHSPC). PATIENTS AND METHODS: A total of 60 patients with RB-intact mHSPC were randomized (1:2) to Arm 1: androgen deprivation (AD) or Arm 2: AD + palbociclib. Primary endpoint was PSA response rate (RR) after 28 weeks of therapy. Secondary endpoints included safety, PSA, and clinical progression-free survival (PFS), as well as PSA and radiographic RR. Tumors underwent exome sequencing when available. Circulating tumor cells (CTC) were enumerated at various timepoints. RESULTS: A total of 72 patients with mHSPC underwent metastatic disease biopsy and 64 had adequate tissue for RB assessment. A total of 62 of 64 (97%) retained RB expression. A total of 60 patients initiated therapy (Arm 1: 20; Arm 2: 40). Neutropenia was the most common grade 3/4 adverse event in Arm 2. Eighty percent of patients (Arm 1: 16/20, Arm 2: 32/40; P = 0.87) met primary PSA endpoint ≤4 ng/mL at 28 weeks. PSA undetectable rate at 28 weeks was 50% and 43% in Arms 1 and 2, respectively (P = 0.5). Radiographic RR was 89% in both arms. Twelve-month biochemical PFS was 69% and 74% in Arms 1 and 2, respectively (P = 0.72). TP53 and PIK3 pathway mutations, 8q gains, and pretreatment CTCs were associated with reduced PSA PFS. CONCLUSIONS: Palbociclib did not impact outcome in RB-intact mHSPC. Pretreatment CTC, TP53 and PIK3 pathway mutations, and 8q gain were associated with poor outcome.

Osseous Healing With Nonrigid Suture Fixation in the Arthroscopic Latarjet Procedure.

BACKGROUND: The Latarjet procedure is a popular means to surgically address anterior glenohumeral joint instability. Although the Latarjet procedure is becoming increasingly common, challenges persist and include postoperative complications secondary to use of the conventional 2 bicortical fixation screws. Recently, a novel surgical technique using a guided surgical approach for graft positioning with nonrigid fixation via a suture suspensory system has been described. PURPOSE: To evaluate healing rates and stability of the grafts in patients who underwent this new Latarjet technique. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We retrospectively gathered anonymized computed tomography (CT) data sets from a total of 107 patients who underwent nonrigid suture fixation using a cortical button fixation for anterior glenohumeral instability. Of the 107 patients, 45 had CT scans performed at 2 different time periods. The CT scans of each patient were compared by 2 fellowship-trained musculoskeletal radiologists. Data recorded included age, sex, date of scan, initial graft position on the glenoid, presence and degree of graft migration relative to the equator on follow-up scan, and percentage of osseous healing (as assessed by osseous bridging) on the follow-up scan. Descriptive statistics were calculated to evaluate the average migration and average percentage of healing at both time points. RESULTS: Our population (n = 45) consisted of 38 men (84.4%) and 7 women (15.6%). The mean age was 27.1 ± 1.1 years. The mean time between initial CT scan (2 weeks postoperatively) and follow-up CT scan was 26 ± 2 weeks. On follow-up scan, reviewer 1 found 75.6% of patients had greater than 75% healing, and reviewer 2 found 70.2% of patients had greater than 75% healing. The center of the graft was measured at or below the equator on follow-up examination in 43 of 45 (95.6%) patients by reviewer 1 and 44 of 45 (97.8%) patients by reviewer 2. CONCLUSION: Based on these findings, nonrigid suture fixation using a cortical button device offers an effective alternative to traditional screw fixation for the Latarjet procedure with a high level of osseous healing and minimal graft migration.

Imaging of gout: findings and pitfalls. A pictorial review.

Gout is the most common crystal arthropathy, accounting for up to 5% of all arthritis. The hallmark of the disease is hyperuricemia with the subsequent deposition of monosodium urate (MSU) crystals in the intra- and extra-articular soft tissues and bones, leading to inflammation of these tissues. Recurrent intermittent flares can result in chronic gouty arthritis leading to cartilage and bone destruction. The most sensitive and specific imaging methods for diagnosing acute gout are ultrasound and dual energy computed tomography (DECT). In the chronic or tophaceous gout, imaging may depict tophi and their local destructive effect on surrounding tissues with characteristic findings on radiographs. In this pictorial review the imaging features of acute and chronic gout on radiographs, ultrasound, and DECT are presented, as well as imaging pitfalls that one needs to be aware.

The Use of Recombinant Human Growth Hormone to Protect Against Muscle Weakness in Patients Undergoing Anterior Cruciate Ligament Reconstruction: A Pilot, Randomized Placebo-Controlled Trial.

BACKGROUND: Anterior cruciate ligament (ACL) tears are common knee injuries. Despite undergoing extensive rehabilitation after ACL reconstruction (ACLR), many patients have persistent quadriceps muscle weakness that limits their successful return to play and are also at an increased risk of developing knee osteoarthritis (OA). Human growth hormone (HGH) has been shown to prevent muscle atrophy and weakness in various models of disuse and disease but has not been evaluated in patients undergoing ACLR. HYPOTHESIS: Compared with placebo treatment, a 6-week perioperative treatment course of HGH would protect against muscle atrophy and weakness in patients undergoing ACLR. STUDY DESIGN: Randomized controlled trial; Level of evidence, 2. METHODS: A total of 19 male patients (aged 18-35 years) scheduled to undergo ACLR were randomly assigned to the placebo (n = 9) or HGH (n = 10) group. Patients began placebo or HGH treatment twice daily 1 week before surgery and continued through 5 weeks after surgery. Knee muscle strength and volume, patient-reported outcome scores, and circulating biomarkers were measured at several time points through 6 months after surgery. Mixed-effects models were used to evaluate differences between treatment groups and time points, and as this was a pilot study, significance was set at P < .10. The Cohen d was calculated to determine the effect size. RESULTS: HGH was well-tolerated, and no differences in adverse events between the groups were observed. The HGH group had a 2.1-fold increase in circulating insulin-like growth factor 1 over the course of the treatment period (P < .05; d = 2.93). The primary outcome measure was knee extension strength, and HGH treatment increased normalized peak isokinetic knee extension torque by 29% compared with the placebo group (P = .05; d = 0.80). Matrix metalloproteinase-3 (MMP3), which was used as an indirect biomarker of cartilage degradation, was 36% lower in the HGH group (P = .05; d = -1.34). HGH did not appear to be associated with changes in muscle volume or patient-reported outcome scores. CONCLUSION: HGH improved quadriceps strength and reduced MMP3 levels in patients undergoing ACLR. On the basis of this pilot study, further trials to more comprehensively evaluate the ability of HGH to improve muscle function and potentially protect against OA in patients undergoing ACLR are warranted. REGISTRATION: NCT02420353 ( ClinicalTrials.gov identifier).

Cartilage icing and chondrocalcinosis on knee radiographs in the differentiation between gout and calcium pyrophosphate deposition.

OBJECTIVE: To determine if findings of "cartilage icing" and chondrocalcinosis on knee radiography can differentiate between gout and calcium pyrophosphate deposition (CPPD). METHODS: IRB-approval was obtained and informed consent was waived for this retrospective study. Electronic medical records from over 2.3 million patients were searched for keywords to identify subjects with knee aspiration-proven cases of gout or CPPD. Radiographs were reviewed by two fellowship-trained musculoskeletal radiologists in randomized order, blinded to the patients' diagnoses. Images were evaluated regarding the presence or absence of cartilage icing, chondrocalcinosis, tophi, gastrocnemius tendon calcification, and joint effusion. Descriptive statistics, sensitivity, specificity, positive and negative predictive values, and accuracy were calculated. RESULTS: From 49 knee radiographic studies in 46 subjects (31 males and 15 females; mean age 66±13 years), 39% (19/49) showed gout and 61% (30/49) CPPD on aspiration. On knee radiographs, cartilage icing showed a higher sensitivity for CPPD than gout (53-67% and 26%, respectively). Chondrocalcinosis also showed a higher sensitivity for CPPD than gout (50-57% versus 5%), with 95% specificity and 94% positive predictive value for diagnosis of CPPD versus gout. Soft tissue tophus-like opacities were present in gout at the patellar tendon (5%, 1/19) and at the popliteus groove in CPPD (15%, 4/27). Gastrocnemius tendon calcification was present in 30% (8/27) of subjects with CPPD, and 5% (1/19) of gout. CONCLUSION: In subjects with joint aspiration-proven crystal disease of the knee, the radiographic finding of cartilage icing was seen in both gout and CPPD. Chondrocalcinosis (overall and hyaline cartilage) as well as gastrocnemius tendon calcification positively correlated with the diagnosis of CPPD over gout.

Hand-Held Portable Versus Conventional Cart-Based Ultrasound in Musculoskeletal Imaging.

BACKGROUND: Portable ultrasound machines are now common, used for point-of-care applications and needle guidance for percutaneous procedures; however, the effectiveness of portable ultrasound in evaluation of the musculoskeletal system has not been fully assessed. PURPOSE: To prospectively evaluate the use of portable hand-held ultrasound in comparison with conventional cart-based ultrasound in evaluation of the musculoskeletal system. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: In this institutional review board-approved, prospective study, 100 consecutive patients with informed consent were imaged through use of both portable and cart-based ultrasound equipment using 12-5 MHz linear transducers. Agreement in ultrasound diagnosis was documented along with expected clinical changes in management if there was disagreement (definitely no, probably no, uncertain, probably yes, definitely yes). Imaging details of disagreement cases were recorded, and descriptive statistics were calculated. RESULTS: There were 42 male and 58 female patients (mean ± SD age, 53 ± 13 years) imaged over a time period of 20 months. Anatomic areas scanned were the shoulder (n = 30), elbow (n = 11), hand and wrist (n = 15), hip (n = 10), knee (n = 11), foot and ankle (n = 12), and others (n = 11). Scanning with conventional ultrasound revealed abnormality in 92% of patients. Agreement in diagnosis made between portable versus cart-based ultrasound was found in 65% of patients. In the 35% of patients with discordant results, the change in diagnosis resulted in no change in clinical management in 46%, probably no change in 29%, uncertain change in 14%, probable change in 11%, and definite change in 0%. The diagnoses changing management (4%; 4/100) included nondetection of a satellite nodule (n = 1), ganglion cyst (n = 1), hernia (n = 1), and underestimated tendon tear (n = 1). CONCLUSION: When compared with conventional cart-based ultrasound, a musculoskeletal diagnosis using portable hand-held ultrasound was concordant or was discordant without clinical relevance in 96% (96/100) of patients. Knowledge of benefits and limitations of portable hand-held ultrasound will help determine areas where specific types of ultrasound equipment can be used.

Ultrasound characterization of pseudoerosions and dorsal joint recess morphology of the hand and wrist in 100 asymptomatic subjects.

PURPOSE: To sonographically characterize pseudoerosions and dorsal joint recess and capsule morphology of the hand and wrist in 100 asymptomatic subjects. METHOD: The metacarpal heads, and dorsal aspects of the lunate, triquetrum, and ulna were evaluated for pseudoerosions including measurements and sonographic characterization. The dorsal recesses of the metacarpophalangeal, radiocarpal, and midcarpal joints were also characterized with regards to echogenicity, fibrillar pattern, hyperemia, and measurements. RESULTS: 100 subjects were included (average age 47 years, range 19-82 years; 52% male, 48% female). Pseudoerosions of metacarpophalangeal heads were seen in every subject, in all metacarpal heads, but most commonly the second and third (99% were bilateral, 97% were multiple); 81.5% involved at least three metacarpal heads; 99% were central with maximum depth of 2.6 mm. At the wrist, in 92% of subjects a bilateral pseudoerosion was present at the dorsal triquetrum, lunate, or ulna. Dorsal joint capsules and recesses at the metacarpophalangeal joints were isoechoic to subdermal fat and fibrillar measuring 3.1-6.3 mm in maximal thickness. The dorsal capsules and recesses of the radiocarpal and midcarpal joints were hypoechoic to subdermal fat, non-fibrillar and with maximal thickness of 3.9 and 3.4 mm, respectively. No hyperemia on color Doppler imaging was noted. CONCLUSIONS: Pseudoerosions are common at the dorsal metacarpal heads, lunate, triquetrum, and ulna, which should not be mistaken for true inflammatory erosions. The characteristic appearances of dorsal joint capsules and recesses should not be confused with synovial hypertrophy.