The value of injectable viscoelastic supplements for joints.

Intra-articular viscoelastic supplements are commonly administered by musculoskeletal radiologists for the treatment of symptomatic osteoarthritis (OA). This article provides an overview of the putative mechanism of action of the agents, a brief review of the evidence base underlying the practice, a commentary on some of the major society guidelines regarding the treatment, and a description of the adverse events that are associated with intra-articular hyaluronic acid administration.

Complications in image-guided musculoskeletal injections.

Complications in musculoskeletal interventions are rare and where they do occur tend to be minor, and often short-lived or self-limiting. Nonetheless, the potential for significant complications exists, and a thorough understanding of both the mechanisms which contribute and the manner in which they may clinically present is of critical importance for all musculoskeletal radiologists involved in performing procedures, both to mitigate against the occurrence of complications and to aid rapid recognition. The purpose of this review is to analyse the relevant literature to establish the frequency with which complications occur following musculoskeletal intervention. Furthermore, we highlight some of the more commonly discussed and feared complications in musculoskeletal intervention, such as the risk of infection, potential deleterious articular consequences including accelerated joint destruction and the poorly understood and often underestimated systemic effects of locally injected corticosteroids. We also consider both extremely rare but emergent scenarios such as anaphylactic reactions to medications, and much more common but less significant complications such as post-procedural pain. We suggest that meticulous attention to detail including strict adherence to aseptic technique and precise needle placement may reduce the frequency with which complications occur.

The Evolving Roles of MRI and Ultrasound in First-Line Imaging of Rotator Cuff Injuries.

Rotator cuff tears are the most likely source of shoulder pain in adults and may cause protracted disability. Management of rotator cuff tears is associated with considerable costs. Accurate diagnosis can guide surgical planning and help achieve a favorable clinical outcome. Although radiography remains the initial imaging test for shoulder injury, the roles of MRI and ultrasound (US) as first-line imaging after radiography are evolving. This article leverages current literature and the practical experience of subspecialty musculoskeletal radiologists from different institutions in describing a practical approach to imaging rotator cuff pathology. Both MRI and US are accurate for identifying rotator cuff tears, but each has advantages and shortcomings. As both modalities currently represent reasonable first-line approaches, considerable practice variation has evolved. Given the low cost of US, imagers should strive to optimize the quality of shoulder US examinations and to build referrer confidence in this modality. The roles of direct CT and MR arthrography as well as imaging evaluation of the postoperative rotator cuff are also considered. Through careful selection among the available imaging modalities and optimal performance and interpretation of such examinations, radiologists can positively contribute to the diagnosis and treatment of patients with rotator cuff injuries.

Multimodal imaging of composite carbon fiber-based implants for orthopedic spinal fixation.

OBJECTIVE: As cancer treatments continue to improve, the incidence of spinal metastases and the need for surgical management of these with fixation procedures are growing rapidly. Traditionally metallic implants, composed of titanium alloy, have been used in surgical fixation of unstable or symptomatic vertebral metastases or traumatic injuries. Metallic implants, however, cause significant artifact on post-operative imaging, degrading image quality and limiting interpretation, and can also impair the planning and delivery of radiotherapy. Composite carbon fiber-based materials, such as carbon fiber-reinforced polyetheretherketone (PEEK), have been developed to overcome these issues and are now available for spinal fixation procedures. We aimed to review the multimodal imaging features of these new implants. MATERIALS AND METHODS: Current literature and a case example from our institution were used to describe the multimodal imaging characteristics and considerations of new carbon fiber-based spinal fixation implants. RESULTS: New carbon fiber-based spinal implants allow far greater visualization of surrounding structures on post-operative cross-sectional imaging, significantly improving diagnostic accuracy and precision of radiotherapy planning, and do not significantly absorb or scatter X-ray photons during radiotherapy delivery. There are, however, important surgical and radiologic considerations associated with the use of carbon fiber-based implants which radiologists must be aware of, such as implications for surgical planning and intra-operative fluoroscopic and post-operative plain radiographic imaging. CONCLUSION: The use of carbon fiber-based implants, rather than traditional metallic implants, for spinal fixation offers significant advantages for post-operative diagnostic imaging and radiotherapy planning and delivery.

Complications in image-guided musculoskeletal injections.

OBJECTIVE: To establish the incidence and define the nature of complications occurring following image-guided musculoskeletal injections at our institution. MATERIALS AND METHODS: All patients undergoing image-guided musculoskeletal injection during the study period (16/3/2016 to 24/01/2020) were included. Departmental records were reviewed to identify all patients describing possible complications following injection, what therapy was required (if any) and what the outcome was. No patients were excluded. Complications were classified as minor or major. Injections were categorised as follows: cervical spine, lumbar facet joint, lumbar nerve root, caudal epidural and 'other'. The complication rate for each individual category of procedure was compared with the combined complication rate for all other categories by constructing contingency tables and using Fisher's exact test. RESULTS: A total of 8226 patients underwent image-guided musculoskeletal injections within the study period. Exactly 100 patients were identified as having reported a complication, producing an overall complication rate of 1.2%. One complication was categorised as 'major', with the patient requiring expedited surgery. The remainder (99 patients) were categorised as having experienced minor complications. The incidence of complications after 'other' injections was significantly greater than for other categories of injection (1.86%, p = 0.028). There was no significant difference in the complication rate for cervical spine (0.93%, p = 0.257), lumbar nerve root (0.85%, p = 0.401), lumbar facet joint (0.67%, p = 0.326) or caudal epidural (1.29%, p = 0.687) injections. 'Other' injections were subsequently further sub-categorised by anatomical site and imaging modality used. Glenohumeral (2.97%, p = 0.0361) and sacro-iliac (3.51%, p = 0.0498) joint injections were associated with a significantly increased risk of complications. There was no difference in the incidence of complications with fluoroscopic or ultrasound guidance. CONCLUSION: In conclusion, image-guided musculoskeletal injections are safe and well-tolerated procedures. Complications are rare, occurring in just 1.2% of patients. 99% of complications are minor, either not requiring intervention or resolving with simple supportive treatment.

Gaelic Sport Injuries.

The Gaelic sports of hurling and football, native to Ireland, are increasing in popularity worldwide. The injury profile of these sports requires multidisciplinary management by sports physicians, orthopaedic surgeons, and musculoskeletal (MSK) radiologists, among others. Advances in imaging modalities and interventional techniques have aided the diagnosis and treatment of sport injuries. In this article, we review the literature and our own institutional experience to describe common injury patterns identified in Gaelic games athletes, their main imaging features and relevant therapeutic interventions. We discuss the increasing prevalence of imaging services at sporting events and the central role of MSK radiologists in sports injury management.

Whole-body MRI of bone marrow: A review.

Technical advances in the last two decades have allowed rapid, high-resolution whole-body magnetic resonance imaging (WBMRI). MRI allows unparalleled visualization and detail in the imaging of bone marrow and surrounding soft tissues. The properties of nuclear magnetic resonance allow superb characterization of bone marrow constituents. WBMRI allows superb characterization of the different types of bone marrow and their natural evolution during the life cycle. Diffusion-weighted WBMRI is an exciting development that adds functional information to anatomical detail. The mainstay of WBMRI for bone marrow abnormalities to date has centered upon staging multiple myeloma and other hematologic bone marrow conditions, and as a valuable tool in quantifying skeletal metastases. Increasingly, WBMRI is being utilized in a variety of additional malignant and nonmalignant conditions. Due to the absence of ionizing radiation, WBMRI represents a valuable screening tool in areas such as malignant transformation in hereditary multifocal exostoses or for the development of ischemic marrow insult in at-risk patients. An additional novel area of use includes postmortem WBMRI for characterization of skeletal injuries. This article provides a state-of-the-art and current review of WBMRI of the bone marrow and highlights potential future areas of development. Level of Evidence: 5 Technical Efficacy Stage: 3 J. MAGN. RESON. IMAGING 2019. J. Magn. Reson. Imaging 2019;50:1687-1701.

Incorporating Cone-Beam CT Into the Diagnostic Algorithm for Suspected Radiocarpal Fractures: A New Standard of Care?

OBJECTIVE. The purpose of this study was to assess the result of adding cone-beam CT to the standard imaging algorithm for patients with suspected radiographically occult traumatic radiocarpal fractures. SUBJECTS AND METHODS. A prospective review was performed on all patients who had cone-beam CT investigation of acute wrist pain after normal initial radiographs. Patients with no identified fractures were clinically reassessed and referred for MRI if concern for a fracture persisted. RESULTS. In all, 117 patients were assessed; 50.4% had fractures identified with a total of 67 radiographically occult fractures. One fracture was identified on MRI that was not seen on cone-beam CT. Cone-beam CT had sensitivity of 98.3% (95% CI, 91.1-100%), specificity of 100% (95% CI, 93.7-100%), positive predictive value of 100%, and negative predictive value of 98.3% (95% CI, 89.1-100%). Accuracy was 99.1% (95% CI, 95.3-100%). CONCLUSION. Incorporating cone-beam CT into routine clinical practice as part of a standardized diagnostic algorithm yielded a 50% fracture detection rate in patients with negative wrist radiographs but ongoing clinical concern for radiocarpal fracture. Cone-beam CT provides more diagnostic information than radiographs at a lower radiation dose than conventional MDCT. Given the poor accuracy of radiographs for acute radiocarpal fractures and the high fracture prevalence in this cohort, we feel that cone-beam CT should be regarded as the new standard of care in the investigation of these patients.

Subtraction multiphase CT angiography: A new technique for faster detection of intracranial arterial occlusions.

OBJECTIVE: To describe and evaluate a novel technical development to improve detection of intracranial vessel occlusions using multiphase CT angiography (MPCTA). MATERIALS AND METHODS: The institutional ethics committee approved the study. Fifty patients (30 consecutive distal (M2 or smaller) anterior circulation occlusions, ten M1 occlusions, ten cases without occlusion) presenting with suspected AIS who underwent MPCTA were included. Post-processing of MPCTA studies created "subtraction" and "delayed enhancement" (DE) datasets. Initially, non-contrast CT and MPCTA studies for each patient were evaluated. Readers' confidence, speed and sensitivity of detection of intracranial vessel occlusions were recorded. After an interval of at least 4 weeks, readers were provided with post-processed images and studies were re-evaluated. RESULTS: While the sensitivity of detection of intracranial vessel occlusions was equal for both conventional MPCTA and subMPCTA, the mean time taken to identify a vessel occlusion decreased by 64 % using subMPCTA (16 s vs. 45 s with conventional MPCTA) (p<0.001). In addition, confidence in interpretation improved (from 4.4 to 4.9) using subMPCTA (p<0.001). CONCLUSION: SubMPCTA is a novel technique that aids in identifying small intracranial vessel occlusions in the suspected AIS patient. SubMPCTA increases confidence in interpretation and reduces the time taken to detect intracranial vessel occlusions. KEY POINTS: • SubMPCTA processes MPCTA data to better demonstrate intracranial arterial occlusions. • SubMPCTA increases confidence and speed of interpretation of MPCTA studies. • SubMPCTA may aid in rapidly differentiating acute ischaemic stroke from stroke mimics.

Injectable Viscoelastic Supplements: A Review for Radiologists.

OBJECTIVE: Hyaluronic acid (HA) is increasingly used by musculoskeletal radiologists in the treatment of osteoarthritis (OA). Although the evidence base for its efficacy is controversial, it remains in common use. With initial evidence suggesting its efficacy in the knee, it is now offered for treating OA of the hip, ankle, and elsewhere. CONCLUSION: HA is available in a wide variety of preparations, which may vary in concentration and chemical composition. Clinicians offering intraarticular HA injection should be familiar with the common preparations available and the principal differences between them, its mechanism of action, and the profile of adverse effects associated with its use.

Sports-Related Groin Pain Secondary to Symphysis Pubis Disorders: Correlation Between MRI Findings and Outcome After Fluoroscopy-Guided Injection of Steroid and Local Anesthetic.

OBJECTIVE: The objective of our study was to correlate patterns of injury on preprocedural MRI with outcome after targeted fluoroscopy-guided steroid and local anesthetic injection of the symphysis pubis and its muscular attachments in a group of athletes with chronic groin pain. MATERIALS AND METHODS: Forty-five patients with chronic sports-related groin pain underwent MRI of the pelvis and a targeted fluoroscopy-guided symphyseal corticosteroid and local anesthetic injection. Preprocedural MRI was reviewed. The presence or absence of a "superior cleft" sign (i.e., rectus abdominis-adductor longus attachment microtearing), "secondary cleft" sign (i.e., short adductor [gracilis, adductor brevis, and pectineus muscles] attachment microtearing), osteitis pubis, and extrasymphyseal pelvic abnormalities was recorded. Patients were followed up a mean time of 23 months after the procedure, and outcome was recorded. Correlation was made between preprocedural MRI findings and outcome. RESULTS: Forty-two percent of the patients had an isolated superior cleft sign, 7% had an isolated secondary cleft sign, and 11% had isolated osteitis pubis. Thirty-one percent of patients had a more complex injury, and 9% had a normal symphysis pubis. Overall, 89% of the patients experienced an improvement in symptoms. The response was sustained after a minimum of 6 months in 58% of the patients. The presence of the superior cleft sign was more frequently associated with a complete recovery. CONCLUSION: Fluoroscopy-guided corticosteroid symphyseal injection is a safe and effective treatment of sports-related groin pain. It is more frequently associated with a complete recovery in patients who display an isolated superior cleft sign on MRI. MRI not only is useful in characterizing groin injuries but also may be helpful in predicting response to therapeutic injection.

The Development of Expertise in Radiology: In Chest Radiograph Interpretation, "Expert" Search Pattern May Predate "Expert" Levels of Diagnostic Accuracy for Pneumothorax Identification.

Purpose To investigate the development of chest radiograph interpretation skill through medical training by measuring both diagnostic accuracy and eye movements during visual search. Materials and Methods An institutional exemption from full ethical review was granted for the study. Five consultant radiologists were deemed the reference expert group, and four radiology registrars, five senior house officers (SHOs), and six interns formed four clinician groups. Participants were shown 30 chest radiographs, 14 of which had a pneumothorax, and were asked to give their level of confidence as to whether a pneumothorax was present. Receiver operating characteristic (ROC) curve analysis was carried out on diagnostic decisions. Eye movements were recorded with a Tobii TX300 (Tobii Technology, Stockholm, Sweden) eye tracker. Four eye-tracking metrics were analyzed. Variables were compared to identify any differences between groups. All data were compared by using the Friedman nonparametric method. Results The average area under the ROC curve for the groups increased with experience (0.947 for consultants, 0.792 for registrars, 0.693 for SHOs, and 0.659 for interns; P = .009). A significant difference in diagnostic accuracy was found between consultants and registrars (P = .046). All four eye-tracking metrics decreased with experience, and there were significant differences between registrars and SHOs. Total reading time decreased with experience; it was significantly lower for registrars compared with SHOs (P = .046) and for SHOs compared with interns (P = .025). Conclusion Chest radiograph interpretation skill increased with experience, both in terms of diagnostic accuracy and visual search. The observed level of experience at which there was a significant difference was higher for diagnostic accuracy than for eye-tracking metrics. (©) RSNA, 2016 Online supplemental material is available for this article.

MR epidurography: distribution of injectate at caudal epidural injection.

OBJECTIVE: To (a) evaluate the feasibility of MR epidurography (MRE) and (b) assess the distribution of injectate using two different volumes at caudal epidural steroid injection. MATERIALS AND METHODS: Twenty patients who were referred with symptomatic low back pain for caudal epidural steroid injection were assigned to have either 10 ml (9/20) or 20 ml (11/20) of injectate administered. Gadolinium was included in the injection. The patients proceeded to MRI where sagittal and coronal T1-weighted fat-saturated sequences were acquired and reviewed in the mid-sagittal and right and left parasagittal views at the level of the exit foramina. RESULTS: Gadolinium was observed at or above the L3/4 disc level in all 11 patients who received 20 ml (100 %), compared with only five of nine patients who received 10 ml (56 %). Injectate was seen to the L4 nerve root level in all 11 patients who received 20 ml (100 %) but only four out of nine patients who received 10 ml (44 %), not even reaching the L5 nerve root level in four further of these nine patients (44 %). Overall, there was a trend to visualize gadolinium at higher levels of the epidural space with higher volumes injected. CONCLUSIONS: Firstly, MR epidurography is a safe technique that allows excellent visualization of the distribution of gadolinium in the epidural space following injection via the caudal hiatus. Secondly, a volume of 10 ml is unlikely to treat L5/S1 disease in almost half of patients at caudal epidural steroid injection and at least 20 ml of injectate is likely required for any medication to reach the desired level.

Frequency of nonthromboembolic imaging abnormalities in pregnant women referred for computed tomography pulmonary arteriography.

PURPOSE: The study sought to determine the frequency of nonthromboembolic imaging abnormalities in pregnant women referred for computed tomography pulmonary arteriography (CTPA). MATERIALS AND METHODS: CTPA studies on 100 consecutive pregnant women performed over a 5-year period were reviewed independently by 2 radiologists, with conflicts resolved by consensus. Age range was 18-43 years (mean 28 years). The presence or absence of pulmonary embolism and of nonthromboembolic imaging abnormalities was recorded. These were graded as A if the abnormalities were thought to provide potential alternative explanations for acute symptoms, B if findings were incidental that required clinical or radiologic follow-up, and C if the findings did not require further action. RESULTS: Pulmonary embolism was seen in 5 women. In 2 of these additional findings of consolidation and infarction were seen. Ninety-five women did not have pulmonary embolism. Eleven women (12%) had grade A abnormalities; 6 cases of consolidation, 2 cases of lobar collapse, and 3 cases of heart failure with pleural effusions. One woman had a grade B abnormality due to the presence of pulmonary nodules. Ten women had incidental grade C abnormalities. CONCLUSION: Pulmonary embolism occurs in 5% of pregnant women referred for CTPA. In pregnant women without embolism on CTPA, potential alternative causes for patient symptoms are seen on CT in 12% of cases.

Is the iPad suitable for image display at American Board of Radiology examinations?

OBJECTIVE: The study aimed to determine the acceptability of the iPad 3 as a display option for American Board of Radiology (ABR) examinations. SUBJECTS AND METHODS: A set of 20 cases for each of nine specialties examined by the ABR was prepared. Each comprised between one and seven images and case information and had been used in previous ABR Initial Certification examinations. Examining radiologists (n = 119) at the ABR oral Initial Certification examinations reviewed sets from one or more specialties on both a 2 MP LED monitor and on the iPad 3 and rated the visibility of the salient image features for each case. The Wilcoxon signed rank test was performed to compare ratings. In addition, a thematic analysis of participants' opinions was undertaken. RESULTS: When all specialties were pooled, the iPad 3 ratings were significantly higher than the monitor ratings (p = 0.0217). The breast, gastrointestinal, genitourinary, and nuclear medicine specialties also returned significantly higher ratings for the visibility of relevant image features for the iPad 3. Monitor ratings were significantly higher for the vascular and interventional specialty, although no images were rated unacceptably poor on the iPad in this specialty. CONCLUSION: The relevant image features were rated more visible on the iPad 3 than on the monitors overall. The iPad 3 was well accepted by a large majority of examiners and can be considered adequate for image display for examination in most or all specialties.

Comparison of 3T MR arthrography and 3T MRI in intra-articular hip pathology: a cost-analysis.

BACKGROUND: MR arthrography (MRA) has previously been the radiological gold standard for investigating labral and chondral lesions of the hip joint. In recent years, 3T MRI has demonstrated comparable accuracy, being adopted as the first-line imaging investigation in many institutions. AIMS: We compare the associated increased cost and radiation dose of the fluoroscopic component of the MRA compared to MRI. METHODS: In this retrospective review over 2 years, 120 patients (mean age 27.3 years ± 13.2, range 8-67) underwent 3T MRA or non-contrast 3T MRI. Three musculoskeletal radiologists reported the data independently. Primary objectives included cost-comparison between each and radiation dose of the fluoroscopic component of the MRA. Secondary objectives included comparing detection of pathology involving the acetabular labrum, femoral cartilage, and acetabular cartilage. RESULTS: Then, 58 (48%) underwent 3T MRA and 62 (52%) patients underwent 3T MRI. The added cost of the fluoroscopic injection prior to MRA was €116.31/patient, equating to €7211.22 savings/year. MRA was associated with a small radiation dose of 0.003 mSv. CONCLUSIONS: Transitioning from 3T MRA to 3T MRI in the investigation of intra-articular hip pathology increases cost savings and reduces radiation dose.

Are brake response times altered post CT-guided cervical spine nerve root injections?

OBJECTIVES: To assess if brake response times are altered pre and post CT-guided cervical spine nerve root injections. METHODS: Brake response times were assessed before and after CT-guided cervical spine nerve root injections in a cohort of patients. The average of 3 brake response times was recorded before and 30 min after injection. Statistical analysis was performed using GraphPad. A paired Student t-test was used to compare the times before and after the injections. RESULTS: Forty patients were included in this study. The mean age was 55 years. There were 17 male and 23 female patients. There was no significant difference in the mean pre and post CT-guided cervical spine nerve root injection brake response times; 0.94 s (range 0.4-1.2 s) and 0.93 s (range 0.5-1.25 s), respectively (P = .77). CONCLUSIONS: Brake response time did not significantly differ pre and 30 min post CT-guided cervical spine nerve root injections. ADVANCES IN KNOWLEDGE: To the authors' best knowledge, there are no current studies assessing brake response times post CT-guided cervical spine nerve root injections. While driving safety cannot be proven by a single metric, it is a useful study in demonstrating that this is not inhibited in a cohort of patients.