Ultrasound-Guided Musculoskeletal Injections.

Musculoskeletal injections serve a variety of diagnostic and therapeutic purposes, with ultrasonography (US) guidance having many advantages: no ionizing radiation, real-time guidance, high spatial resolution, excellent soft tissue contrast, and the ability to identify and avoid critical structures. Sonography can be cost effective and afford flexibility in resource-constrained settings. This article describes US-guided musculoskeletal injections relevant to many radiology practices and provides experience-based suggestions. Structures covered include multiple joints (shoulder, hip), bursae (iliopsoas, subacromial-subdeltoid, greater trochanteric), peripheral nerves (sciatic, radial), and tendon sheaths (posterior tibial, peroneal, flexor hallucis longus, Achilles, long head of the biceps). Trigger point and similar targeted steroid injections, as well as calcific tendinopathy barbotage, are also described.

Advanced MRI Techniques of the Shoulder Joint: Current Applications in Clinical Practice.

OBJECTIVE: We are fortunate to live in a time when real advances in medicine are happening at an increasingly rapid pace. This is especially true in the field of radiology, and keeping abreast of these advances is one of the main challenges of clinical practice. Traditionally, cutting edge techniques in our field have been researched and validated at major academic medical centers before slowly making their way into the armamentarium of routine clinical practice. However, the improved ability to communicate and disseminate information in our modern age has facilitated more rapid implementation of new techniques to allow us to better serve our patients. CONCLUSION: As such, this article aims to review the current standards for MRI of the shoulder used in routine practice. Furthermore, we will discuss some of the most recent advances in shoulder MRI, with particular emphasis on the applicability of an additional axial 3D T1-weighted FLASH sequence with Dixon-based water-fat separation in routine clinical practice that can be useful in characterizing several commonly encountered pathologic processes of the shoulder joint.

Shear Wave Ultrasound Elastographic Evaluation of the Rotator Cuff Tendon.

OBJECTIVES: (1) Assess the association between the B-mode morphologic appearance and elasticity in the rotator cuff tendon using shear wave elastography (SWE). (2) Assess the association between SWE and symptoms. METHODS: Institutional Review Board approval and informed consent were obtained. A retrospective review identified 21 studies in 19 eligible patients for whom SWE was performed during routine sonographic evaluations for shoulder pain. Evaluations were compared with 55 studies from 16 asymptomatic volunteers and 6 patients with asymptomatic contralateral shoulders. Repeated studies were accounted for by resampling. Proximal and distal tendon morphologic characteristics were graded from 1 to 4 (normal to full-thickness tear), and average shear wave velocity (SWV) measurements were obtained at both locations. In 68 examinations, deltoid muscle SWV measurements were available for post hoc analysis. RESULTS: The morphologic grade and SWV showed weak-to-moderate negative correlations in the proximal (P < .001) and distal (P = .002) rotator cuff tendon. A weakly significant SWV decrease was found in the proximal tendon in symptomatic patients (P = .049); no significant difference was seen in the distal tendon. The deltoid muscle SWV showed weak-to-moderate negative correlations with the morphologic grade in the proximal (P = .004) and distal (P = .007) tendon; the deltoid SWV was also significantly lower in symptomatic shoulders (P = .001). CONCLUSIONS: Shear wave elastography shows tendon softening in rotator cuff disease. It captures information not obtained by a morphologic evaluation alone; however, a poor correlation with symptoms suggests that SWE will be less useful in workups for shoulder pain than for preoperative assessments of tendon quality. Deltoid muscle softening seen in morphologically abnormal and symptomatic patients requires further exploration.

MR Imaging of Knee Cartilage Injury and Repair Surgeries.

Cartilage injuries are common and may predispose to early accelerated osteoarthritis. Magnetic resonance (MR) imaging is critical in the detection and characterization of acute and chronic cartilage injuries. Several surgical approaches including microfracture, osteochondral allografting, autologous osteochondral transfer system, and autologous chondrocyte implantation have been developed to treat cartilage lesions. The goals of these treatments include relief of symptoms, restoration of joint function, and delay of progression of osteoarthritis. Imaging evaluation by MR imaging plays a crucial role in diagnosis and surgical planning as well as monitoring for postoperative complications.

Bilateral Distal Radius Fractures in a Patient with Osteogenesis Imperfecta: A Case Report.

CASE: Longitudinal follow-up of a 53-year-old woman with osteogenesis imperfecta (OI) Type III and concurrent bilateral distal radius fractures is reported. She had a right-sided displaced fracture and a left-sided minimally displaced fracture. Operative management of the displaced fracture showed adequate healing in 10 weeks. The minimally displaced fracture failed nonoperative management but did adequately heal after operative intervention. CONCLUSION: Early surgical intervention of distal radius fractures may be considered in patients with severe OI, even in fractures with minimal displacement. This is likely particularly important with patients who are heavily reliant on their upper extremities for mobility.

Mass-Like Fat at the Medial Midfoot: A Common Pseudolesion.

Background Fatty masses are common and may be encountered in the foot and ankle. In some cases, normal subcutaneous fat may be mistaken for a discrete mass. Aims The aim of this study was to evaluate the common finding of prominent subcutaneous fat at the medial midfoot resembling a lipoma and to determine the prevalence of this pseudolesion by applying a series of potential size cutoff criteria. Materials and Methods Three musculoskeletal radiologists retrospectively evaluated 91 sequentially performed magnetic resonance imaging examinations of the ankle to measure fat resembling a discrete lipoma at the medial midfoot. Each blinded reader measured the largest area of continuous subcutaneous fat in orthogonal axial, coronal craniocaudal, and coronal transverse dimensions. Patient age, sex, and study indications were also recorded. Statistical analysis was performed with R and SAS 9.4 software Results A discrete fatty pseudolesion as defined by measuring at least 1 cm in all planes by measurements of at least two of three readers was present in 87% of cases (79 of 91). When a size criterion of 1.5 cm was used, a pseudolesion was documented in 14% of cases (13 of 91). There was a significant correlation between larger pseudolesion size and female sex in the axial plane; however, there was no correlation in the coronal craniocaudal and coronal transverse dimensions. Conclusions Subcutaneous fat at the medial midfoot often has a mass-like appearance that could be mistaken for a lipoma. It is important to recognize this pseudolesion variant and not to confuse the imaging appearance for a discrete mass.

Dipole analysis of magnetoencephalographic data during continuous shape copying.

High density, whole head magnetoencephalography (MEG) was used to study ten healthy human subjects (five females and five males) participating in a continuous shape-copying task. The task was performed with eyes open and fixated. The three-part task began with 45 s of fixation on a blue dot, after which the dot turned red, and a pentagon was presented around it. Subjects continued to fixate on the red dot for 45 s, after which it turned green. The green dot instructed subjects to begin copying the shape continuously for 45 s, without visual feedback, using a joystick mounted at arm's length. Data were collected at 1,017.25 Hz with a 248 sensor axial-gradiometer system. After cardiac artifact subtraction (Leuthold 2003), each corner was identified, and 1 s epochs (centered on each corner) were averaged and filtered from 1 to 44 Hz. Grand average flux maps demonstrated dipolar distributions identifying the most relevant sensors. With these sensors, which were located over flux extrema (Valaki et al. 2004), dipole models were used for source localization within subjects. Consistent dipole locations included the left motor cortex, bilateral parietal, frontal and temporal regions, and the occipital cortex. These results indicate that MEG source-localization may be derived from a limited number of trials of continuous data, and that visual cortex activity may be consistently present during continuous motor activity despite the absence of novel visual stimulation and eye-movements.

Magnetoencephalographic signals predict movement trajectory in space.

Brain-machine interface (BMI) efforts have been focused on using either invasive implanted electrodes or training-extensive conscious manipulation of brain rhythms to control prosthetic devices. Here we demonstrate an excellent prediction of movement trajectory by real-time magnetoencephalography (MEG). Ten human subjects copied a pentagon for 45 s using an X-Y joystick while MEG signals were being recorded from 248 sensors. A linear summation of weighted contributions of the MEG signals yielded a predicted movement trajectory of high congruence to the actual trajectory (median correlation coefficient: r=0.91 and 0.97 for unsmoothed and smoothed predictions, respectively). This congruence was robust since it remained high in cross-validation analyses (based on the first half of data to predict the second half; median correlation coefficient: r=0.76 and 0.85 for unsmoothed and smoothed predictions, respectively).