High-resolution ultrasound approach to quadrangular joint in carpal boss: Everything musculoskeletal sonographer should know.

At the quadrangular joint (QAJ) of the carpus, a rare bony protuberance called carpal boss (CB) may occur. This bone abnormality may be due to osteophytes development or os styloideum. Symptomatic patients may complain pain, swelling, and restrictions in hand motion. These symptoms result from joint degenerative-inflammatory changes, development of ganglion cyst/bursitis, or tendons pathology. Correct diagnosis and appropriate management can be achieved through high-resolution ultrasonography (HR-US). The purpose of this review is to define the pathology spectrum around and within the QAJ in CB. The role of HR-US is highlighted and the standard technique for the QAJ assessment is described.

Lunotriquetral Coalition.

Lunotriquetral (LT) coalition is the most common carpal coalition. Four morphological types of LT coalition have been described. LT coalition is usually asymptomatic, but rarely a fibrocartilaginous type may cause ulnar wrist pain. We report a case of bilateral asymptomatic LT coalition that was seen incidentally on conventional radiography taken after a wrist injury. Conventional radiography is the first imaging technique to detect and classify this type of LT coalition. Magnetic resonance imaging is a useful tool to investigate possible associated pathology of the carpal joints, particularly if surgical treatment of a symptomatic patient is anticipated.

Interdisciplinary consensus statements on imaging of DRUJ instability and TFCC injuries.

OBJECTIVES: The purpose of this agreement was to establish evidence-based consensus statements on imaging of distal radioulnar joint (DRUJ) instability and triangular fibrocartilage complex (TFCC) injuries by an expert group using the Delphi technique. METHODS: Nineteen hand surgeons developed a preliminary list of questions on DRUJ instability and TFCC injuries. Radiologists created statements based on the literature and the authors' clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panelists consisted of twenty-seven musculoskeletal radiologists. The panelists scored their degree of agreement to each statement on an 11-item numeric scale. Scores of "0," "5," and "10" reflected complete disagreement, indeterminate agreement, and complete agreement, respectively. Group consensus was defined as a score of "8" or higher for 80% or more of the panelists. RESULTS: Three of fourteen statements achieved group consensus in the first Delphi round and ten statements achieved group consensus in the second Delphi round. The third and final Delphi round was limited to the one question that did not achieve group consensus in the previous rounds. CONCLUSIONS: Delphi-based agreements suggest that CT with static axial slices in neutral rotation, pronation, and supination is the most useful and accurate imaging technique for the work-up of DRUJ instability. MRI is the most valuable technique in the diagnosis of TFCC lesions. The main indication for MR arthrography and CT arthrography are Palmer 1B foveal lesions of the TFCC. CLINICAL RELEVANCE STATEMENT: MRI is the method of choice for assessing TFCC lesions, with higher accuracy for central than peripheral abnormalities. The main indication for MR arthrography is the evaluation of TFCC foveal insertion lesions and peripheral non-Palmer injuries. KEY POINTS: • Conventional radiography should be the initial imaging technique in the assessment of DRUJ instability. CT with static axial slices in neutral rotation, pronation, and supination is the most accurate method for evaluating DRUJ instability. • MRI is the most useful technique in diagnosing soft-tissue injuries causing DRUJ instability, especially TFCC lesions. • The main indications for MR arthrography and CT arthrography are foveal lesions of the TFCC.

Visualizing the Individual Arterial Anatomy of the Face Through Augmented Reality- A Useful and Accurate Tool During Dermal Filler Injections.

Background: The arterial anatomy of the face is extremely variable. Despite numerous cadaver dissections and anatomical descriptions, the exact location of the superficial facial arteries remains unpredictable. This ignorance is a determining factor in the pathophysiology of intravascular filler injections, potentially causing skin necrosis and blindness. Objectives: The main objective of this study is to evaluate the accuracy of an augmented reality (AR) application that visualizes the individual arterial anatomy of the face. Methods: A workflow was developed during which a magnetic resonance angiography (MRA) mapped the superficial arteries of the face. The images were further processed into an AR image that was visualized on the patient's face using a specifically designed smartphone application. The accuracy of the AR image and the position of each individual artery were analyzed using duplex ultrasound (US). Results: A total of 216 facial arteries were visualized in 20 patients. The superficial temporal (100%), supratrochlear (92.5%), facial (75%), and angular (82.5%) arteries were visualized the most. The inferior labial (17.5%), dorsal nasal (22.5%), and supraorbital (42.5%) arteries were the most difficult to visualize through MRA. The average deviation between the artery visible on the AR image and the location assessed by US was 0.30 mm (standard deviation = +/- 0.66 mm). There were no complications reported. Conclusions: The combination of a risk-free MRA to map the individual arteries of the face and the processing into an AR image may be considered as a useful and accurate tool during dermal filler injections to potentially minimize the risk of intravascular filler injections.

The Usefulness of Magnetic Resonance Angiography to Analyze the Variable Arterial Facial Anatomy in an Effort to Reduce Filler-Associated Blindness: Anatomical Study and Visualization Through an Augmented Reality Application.

BACKGROUND: The use of soft tissue fillers for facial rejuvenation is increasing rapidly and the complications, unfortunately, follow the same path. Blindness caused by intravascular filler injections is a rare but devastating complication. Knowledge of the individual arterial anatomy may aid the injector in avoiding injecting into an artery and thus to prevent blindness. OBJECTIVES: To evaluate if the use of magnetic resonance angiography (MRA) may visualize the arterial facial anatomy in a contrast- and radiation-free way and study the individual arterial variations using an augmented reality (AR) image. METHODS: The individual arterial anatomy of the 3 terminal branches of the ophthalmic artery (supraorbital [SO]; supratrochlear [STr]; and dorsal nasal [DN] arteries) of 20 volunteers was studied by a 3-Tesla MRI, combining infrared (IR) facial warming and 3-dimensional time-of-flight multiple overlapping thin slab acquisition MRA. The resulting visualization of the facial arteries was shown on the patient's face through AR technology. RESULTS: The MRA was able to visualize the SO in 90.0%, STr in 92.5%, and DN arteries in 75% of the examined patients, as well as numerous variations in both vessel localization and path. Furthermore, a proof-of-concept of the AR visualization of the individual arterial anatomy was successfully implemented. CONCLUSIONS: Dermal filler injectors should be aware of the risk of filler-induced blindness and familiarize themselves with the visualization of the variable facial vascular anatomy. The implementation of a one-time MRA and subsequent AR visualization may be useful in the accurate planning of minimally invasive facial rejuvenation procedures.

Interdisciplinary consensus statements on imaging of scapholunate joint instability.

OBJECTIVES: The purpose of this agreement was to establish evidence-based consensus statements on imaging of scapholunate joint (SLJ) instability by an expert group using the Delphi technique. METHODS: Nineteen hand surgeons developed a preliminary list of questions on SLJ instability. Radiologists created statements based on the literature and the authors' clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panellists consisted of twenty-seven musculoskeletal radiologists. The panellists scored their degree of agreement to each statement on an eleven-item numeric scale. Scores of '0', '5' and '10' reflected complete disagreement, indeterminate agreement and complete agreement, respectively. Group consensus was defined as a score of '8' or higher for 80% or more of the panellists. RESULTS: Ten of fifteen statements achieved group consensus in the second Delphi round. The remaining five statements achieved group consensus in the third Delphi round. It was agreed that dorsopalmar and lateral radiographs should be acquired as routine imaging work-up in patients with suspected SLJ instability. Radiographic stress views and dynamic fluoroscopy allow accurate diagnosis of dynamic SLJ instability. MR arthrography and CT arthrography are accurate for detecting scapholunate interosseous ligament tears and articular cartilage defects. Ultrasonography and MRI can delineate most extrinsic carpal ligaments, although validated scientific evidence on accurate differentiation between partially or completely torn or incompetent ligaments is not available. CONCLUSIONS: Delphi-based agreements suggest that standardized radiographs, radiographic stress views, dynamic fluoroscopy, MR arthrography and CT arthrography are the most useful and accurate imaging techniques for the work-up of SLJ instability. KEY POINTS: • Dorsopalmar and lateral wrist radiographs remain the basic imaging modality for routine imaging work-up in patients with suspected scapholunate joint instability. • Radiographic stress views and dynamic fluoroscopy of the wrist allow accurate diagnosis of dynamic scapholunate joint instability. • Wrist MR arthrography and CT arthrography are accurate for determination of scapholunate interosseous ligament tears and cartilage defects.

Visualization techniques of the facial arteries.

BACKGROUND: As the face is known for its extreme variation in vascular anatomy and the number of filler-associated complications due to intra-arterial injection is increasing, we are in need of a method to visualize anyone's individual arterial anatomy of the face in a completely harmless way. AIMS: The different medical imaging methods and a recently developed MRA protocol are reviewed. METHODS: The literature of the last twenty years-with special attention for the last five years-concerning the different medical imaging modalities of the facial arteries was reviewed. RESULTS: A harmless visualisation of the facial arteries is currently only possible with US or MRA. US may identify single vessels but never the complete arterial network. A combination of IR "heat enhancement" and a MRA 3D-TOF sequence might make it feasible to visualize a large number of facial arteries in a risk-free, radiation-free, contrast-free and non-invasive way. CONCLUSION: Currently, a new combination of IR "heat enhancement" and a MRA 3D-TOF sequence might be the only method to visualize a large number of facial arteries.

Infrared Thermally Enhanced 3-Dimensional Time of Flight Magnetic Resonance Angiography Imaging for the Visualization of the Arteries of the Face.

BACKGROUND: The face is known for its extreme variation in vascular anatomy. Furthermore, the rapidly increasing number of filler treatments leads to an increase in severe filler-associated complications (such as skin necrosis and blindness) due to intra-arterial injection. Visualizing a patient's individual complete facial arterial anatomy in a contrast- and radiation-free way has not been published before. This innovative imaging technique could, therefore, enhance the safety of minimally invasive surgical procedures as it provides a harmless way to map the arteries of the face. OBJECTIVES: Evaluate a newly developed imaging technique to visualize the arteries of the face in a noninvasive and radiation-free manner. METHODS: The individual arterial facial anatomy of 20 volunteers was studied by an imaging technique, combining infrared (IR) facial warming and 3-dimensional (3D) time of flight (TOF) magnetic resonance angiography (MRA). The source and maximum intensity projection images were assessed by 2 investigators, familiar with the anatomy of the face. RESULTS: The MRA technique visualized most of the main facial arteries, albeit in a variable way. The main facial branches of the external carotid artery (facial, angular, supralabial, and superficial temporal arteries) were illustrated well, whereas the visualization of the internal carotid branches (supratrochlear and supraorbital arteries) and nasal branches (dorsal nasal and lateral nasal arteries) was less consistent. CONCLUSIONS: The combination of IR "heat-induced enhancement" and a 3D-TOF MRA sequence may actually be an important step toward the visualization of the variable facial vascular anatomy in a noninvasive, radiation-free, and contrast-free manner.

Hand and Wrist: A Kaleidoscopic View of Accessory Ossicles, Variants, Coalitions, and Others.

Accessory bones, variants, and coalitions are not uncommon at the hand-wrist region. They are often overlooked because they are usually asymptomatic and found incidentally on imaging. However, they may sometimes present as a (painful) swelling or mimic a (sequel of a) fracture. Other symptoms may be attributed to impingement and exercise-related pain. Thorough knowledge of the anatomy, systematic imaging analysis, and the awareness of their existence are the clues to a correct identification. Plain radiography and magnetic resonance imaging (MRI) play a pivotal role in the correct diagnosis. In general, signal intensity on MRI is similar to the normal bony structures. However, concomitant bone marrow edema may indicate the presence of impingement. Therefore, MRI sequences with fat suppression should be included in case of symptomatic findings. This article provides a kaleidoscopic overview of some of the prevalent bony anomalies of the hand-wrist region and their potential pathogenic nature.

Secondary Abutment Syndromes of the Wrist in Trauma: A Pictorial Essay.

Traumatic lesions of the wrist occur frequently and may give rise to underdiagnosed secondary abutment syndromes. The latter are a common cause of incapacitating pain and limited range of motion, despite minimal or even absent alterations on radiographs. Moreover, the complex wrist anatomy often results in ignorance or underappreciation of these syndromes. This paper presents a pictorial review of frequent and rare secondary abutment syndromes at the wrist joint, which - in contrast to primary abutment syndromes - are not based on anatomical variants or congenital deformations. The merit of each imaging modality is briefly mentioned.

Accessory Muscles of the Extremities.

Accessory muscles and variations are not uncommon at the upper and lower extremity. They are often overlooked because they are asymptomatic and present as incidental findings on imaging. However, they may present as a soft tissue swelling, thereby mimicking soft tissue tumors. Other symptoms are attributed to impingement on neurovascular structures and to exercise-related pain. Thorough knowledge of the anatomy, systematic imaging analysis, and the awareness of it are the clues to correct identification. On ultrasound, accessory muscles have a similar echotexture as other muscles, whereas the signal intensity on magnetic resonance imaging (MRI) is similar to muscle. Because of the intrinsic contrast with the adjacent intermuscular fat, accessory muscles are best depicted on MRI without fat suppression. This article provides a short overview of the anatomy of most prevalent accessory muscles of the upper and lower limb and its potential pathogenic nature.

The "second ulnar groove", a MRI sign suggesting a previous palmar luxation of the ulna at the distal radioulnar joint.

INTRODUCTION: A cortical lined impaction on the radiodorsal side of the ulnar head may be at the origin of a "second ulnar groove" (SUG). The goal of this article is to illustrate this MRI sign, prompting for further investigation of the distal radioulnar joint (DRUJ). Hence associated soft tissue pathology may be detected, which may lead to instability. MATERIAL AND METHODS: Following an anterior luxation of the ulna at the DRUJ a second cortical lined groove in a previously normal distal ulna was discovered. A data base review from January 2008 to August 2016 of the axial FS PD-TSE WI 1.5T MRI views of 1.716 patients was accomplished in search of similar bone defects. RESULTS: Eight patients with previous severe wrist trauma presented with a similar posttraumatic ulnar bone defect. The preceding anterior luxation at the DRUJ was only clearly demonstrated in five patients. However, two more patients had a residual anterior subluxation. Different imaging techniques are discussed and the differential diagnosis is well illustrated. CONCLUSIONS: The type of trauma, the specific location and the morphology of a second ulnar groove, all compatible with a sequel of an anterior luxation of the ulna at the DRUJ, should lead to a further specific clinical and MRI revaluation of the DRUJ.

MRI diagnosis of carpal boss and comparison with radiography.

Background A carpal boss is a potentially painful bony mass in the region of the second or third carpometacarpal joint. The combination of clinical examination and radiography is usually sufficient for the diagnosis. Purpose To determine whether magnetic resonance imaging (MRI) examination of the quadrangular joint can assist the diagnosis of persistent pain near a carpal boss. Material and Methods Fifty-seven patients with a carpal boss were retrospectively reviewed using MRI and conventional radiographs and compared to an asymptomatic control group. Results MRI demonstrated a variable morphology and a variety of bone and soft tissue abnormalities associated with carpal boss. Bone marrow edema around the quadrangular joint shows a significant correlation (Fisher's exact test: P < 0.001) and a positive correlation (Pearson's test r = 0.632, significant at the 0.01 level [two-tailed]) with a painful carpal boss. Conclusion MRI offers detailed examination of bone and soft tissue abnormalities associated with a carpal boss. Local bone marrow edema strongly correlates with a painful carpal boss.

Imaging Findings at the Quadrangular Joint in Carpal Boss.

A carpal boss was initially described as a bony, sometimes painful mass at the quadrangular joint. Clinical examination and plain radiography will usually reveal the diagnosis. US and CT may add information. MRI may illustrate a variable bony morphology and additional bony and soft tissue pathologies. Bone marrow edema shows a significant correlation with a painful carpal boss. Hence, MRI may be of additional diagnostic value in patients with persistent pain and preoperatively. This paper presents a review of the anatomy and pathology in carpal boss. The merit of each imaging modality - in particular MRI - is mentioned.

Familial Multiple Cavernous Malformation Syndrome: MR Features in This Uncommon but Silent Threat.

Cerebral cavernous malformations (CCM) are vascular malformations in the brain and spinal cord. The familial form of cerebral cavernous malformation (FCCM) is uncommon. This autosomal dominant pathology mostly presents with seizures and focal neurological symptoms. Many persons affected by FCCM remain asymptomatic. However, acute hemorrhages may appear over time. MRI demonstrates multiple focal regions of susceptibility induced signal loss, well seen on gradient-echo sequences (GRE) or even better on susceptibility-weighted imaging (SWI). The presence of a single CCM - especially in young persons - without history of FCCM does not exclude this diagnosis. Some clinicians also advise an MRI of the spinal cord at the time of diagnosis to serve as a baseline and a control MRI of the brain every one to two years. MRI is certainly indicated in individuals with obvious new neurologic symptoms. Symptomatic siblings should also undergo an MRI of the brain to determine presence, size, and location of the lesions. Even in asymptomatic siblings, a screening MRI may be considered, as there may be an increased risk of hemorrhage, spontaneous or due to the use of certain medications; the knowledge of the presence and the type of these lesions are important. Surgical removal of a CCM may be justified to prevent a life-threatening hemorrhage. Control MRI may reveal the postoperative outcome.