Frondlike Synovitis on MRI and Correlation With Polyethylene Surface Damage of Total Knee Arthroplasty.

OBJECTIVE: The purpose of this study is to determine the association between polyethylene surface damage and the severity of frondlike hypertrophied synovitis, joint distention, capsular thickness, and osteolysis on MRI compared with other patient factors. Another goal of this study is to ascertain the interobserver reliability in MRI evaluation of synovitis. MATERIALS AND METHODS: MR images of 61 patients who had undergone revision total knee arthroplasty (TKA) were retrospectively reviewed. The two MRI reviewers were blinded to clinical and retrieval data. The retrieved polyethylene tibial inserts were graded to determine the severity of surface damage. The association of MRI features with surface damage was assessed using Spearman correlation coefficients and multiple linear regression. Interobserver reliability was assessed using the kappa statistic. RESULTS: Correlations were moderate between the surface damage score and MRI synovitis severity (r = 0.46; p < 0.001) and joint distention (r = 0.41; p = 0.001). Multiple linear regression showed that the MRI synovitis score (p = 0.045), male sex (p = 0.007), body mass index (p = 0.041), and the time since implantation (p < 0.0001) predicted the surface damage score. Substantial interobserver agreement was shown for MRI grading of synovitis (κ = 0.72; 95% CI, 0.65-0.80). CONCLUSION: The magnitude of frondlike hypertrophied synovitis on MRI is significantly associated with polyethylene surface damage in patients who undergo revision TKA. The finding of severe frondlike synovitis on MR images of patients with TKA should raise the possibility of polyethylene surface damage. However, time since implantation is a stronger predictor of surface damage.

Total Knee Arthroplasty: Diagnostic Accuracy of Patterns of Synovitis at MR Imaging.

Purpose To determine the diagnostic accuracy of magnetic resonance (MR) imaging for differentiating synovial patterns in patients with total knee arthroplasty (TKA), whether diagnostic accuracy differs in index versus revision TKA, and interobserver and intraobserver reliability for assessment of synovial patterns at MR imaging. Materials and Methods This retrospective cross-sectional study included 108 consecutive patients with TKAs who underwent MR imaging within 1 year prior to revision surgery from 2012 to 2014. Institutional review board approval was obtained, with waiver of the need to obtain informed consent. MR images were reviewed, and cases were qualitatively categorized by the appearance of the synovium as one of the following: frondlike and hypertrophied (particle-induced synovitis), lamellated and hyperintense (infection), and a homogeneous effusion with the signal intensity of fluid (nonspecific synovitis). The MR imaging appearance was compared with surgical and microbiology reports as the reference standard to determine the sensitivity, specificity, and positive and negative predictive values for the index TKA and revision TKA cohorts. Results For all patients combined, MR imaging had 0.907-0.930 sensitivity and 0.723-0.738 specificity for a surgical diagnosis of complications related to polyethylene wear (including osteolysis and loosening); 0.652-0.783 sensitivity and 0.976-0.988 specificity for infection; and 0.643-0.667 sensitivity and 0.894-0.939 specificity for stiffness, instability, and nonspecific pain. Diagnostic accuracy was higher in the index TKA cohort than in the revision TKA cohort. Interobserver and intraobserver reliabilities were almost perfect (κ = 0.82 and κ = 0.83, respectively). Conclusion MR imaging can help distinguish qualitative differences in the appearance of the synovium in TKA between particle-induced synovitis, infection, and nonspecific synovitis, with almost perfect interobserver and intraobserver reliability. Diagnostic accuracy is higher for index TKA than for revision TKA. © RSNA, 2016.

MRI Evaluation of Femoroacetabular Impingement After Hip Preservation Surgery.

OBJECTIVE: This article reviews the surgical treatment options for femoroacetabular impingement (FAI), including labral repair and osteochondroplasty, and the expected postoperative appearance on MRI. Complications, including residual osseous deformities, chondral injury, adhesions, femoral neck stress fractures, osteonecrosis, instability, malpositioned suture anchors, and infection, will also be discussed. CONCLUSION: Knowledge of the surgical treatment of FAI can assist in improving our understanding of the expected postoperative MRI appearance and in evaluating surgical complications.

MRI of Polyethylene Tibial Inserts in Total Knee Arthroplasty: Normal and Abnormal Appearances.

OBJECTIVE: The purpose of this study was to describe the normal and abnormal MRI appearances of polyethylene tibial inserts. Subjects who underwent MRI before revision total knee arthroplasty were identified. The polyethylene tibial insert's shape was categorized on MRI, and the presence of abnormalities was noted. CONCLUSION: The shape of the polyethylene tibial insert varied with the design. Polyethylene tibial insert abnormalities seen on MRI included displacement and fracture. MRI distinguishes various designs of polyethylene tibial inserts and can show associated abnormalities.

CT features of HER2-mutant lung adenocarcinomas.

OBJECTIVES: To describe the radiological phenotype of HER2-mutant lung cancers on CT at presentation. METHODS: Eligible patients with lung adenocarcinomas with HER2 mutations were stage-matched with two control groups (EGFR- and KRAS-mutant groups). Evaluated CT features of the primary tumor included size, location, consistency, contour, presence of pleural tags and pleural retractions. Presence of pleural effusions, lung metastases, adenopathy, chest wall invasion, and were also recorded. Wilcoxon rank-sum and Fisher's exact tests were used to compare continuous and categorical features, respectively. RESULTS: One hundred and fifty-four patients were identified: 50 (33%) harbored HER2 mutations, 56 (36%) harbored KRAS mutations, and 48 (31%) harbored EGFR mutations. Compared with KRAS, HER2 tumors presented as smaller lesions (2.3 cm versus 2.9 cm, p = 0.005 for length; 1.6 cm versus 2.1 cm, p = 0.002 for width) with the presence of pleural tags (74% vs. 52%, p = 0.03), pleural retractions (58% vs. 39%, p = 0.006), ipsilateral hilar (36% vs. 16%, p = 0.03) and scalene/supraclavicular N3 adenopathy (24% vs. 7%, p = 0.03). Compared with EGFR, pleural retractions were more prevalent among the HER2 tumors (58% vs. 37%, p = 0.05). CONCLUSIONS: Lung adenocarcinomas with HER2 gene mutation exhibit an aggressive behavior manifesting by higher incidence of local invasion, compared to KRAS and EGFR mutant controls, and a nodal metastatic spread compared to KRAS-mutant control. This is the first radiogenomics study of HER2 mutations in lung cancer.

Comparison of Magnetic Resonance Imaging and Radiographs for Evaluation of Carpal Osteoarthritis.

Background We sought to evaluate the interobserver and intraobserver reliability of radiographs and magnetic resonance imaging (MRI) for grading of osteoarthritis in patients with scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC), and to determine whether MRI is more likely than radiographs to detect carpal osteoarthritis. Methods Radiographs and MR studies of 46 patients with SLAC and SNAC arthritis were reviewed by two hand surgeons and two radiologists and were graded according to severity of osteoarthritis at seven carpal joints. Interobserver and intraobserver reliability was assessed using a weighted kappa analysis. Odds ratios were calculated to compare the likelihood of MRI versus radiographs in the determination of moderate or severe osteoarthritis. Results Measures of reliability were higher for MRI than radiographs. For radiographic assessment of all patients combined, interobserver agreement was moderate and intraobserver agreement was also moderate. For MRI, interobserver agreement was substantial and intraobserver agreement was almost perfect. In all joints combined for patients with SLAC and SNAC, MRI was 2.42 times more likely to demonstrate moderate osteoarthritis compared with radiographs. In patients with SLAC, MRI was 11.73 times more likely than radiographs to show moderate osteoarthritis at the radiolunate joint. In patients with SNAC, there was no difference in demonstration of moderate osteoarthritis on MRI compared with radiographs. Conclusion Carpal osteoarthritis can be more reliably assessed on MRI than radiographs. MRI is more sensitive at demonstrating moderate changes of osteoarthritis than radiographs, especially at the radiolunate joint in patients with SLAC arthritis. This has implications for surgical management of SLAC/SNAC arthritis and preoperative planning. MRI should be included in the diagnostic workup and evaluation of patients with SLAC and SNAC arthritis. Level of Evidence Diagnostic III.

Safety of Hip Anchor Insertion From the Midanterior and Distal Anterolateral Portals With a Straight Drill Guide: A Cadaveric Study.

BACKGROUND: During arthroscopic labral refixation, suture anchors are typically inserted from either the midanterior (MA) portal or the distal anterolateral (DALA) portal; however, no studies have previously compared these techniques. Purpose/Hypothesis: The purpose of this study was to compare acetabular rim accessibility and associated complication rates of anchor insertion from these portals. We hypothesized that rim access would be better from the DALA portal. Additionally, we hypothesized that articular surface perforation would occur more commonly from the MA portal while psoas tunnel perforation would occur more commonly from the DALA portal. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen pelvic cadaveric specimens (32 hips) were obtained and arthroscopic surgery performed in the supine position. Suture anchors were placed at 7 predetermined locations (9-, 11-, 12-, 1-, 2-, 3-, and 4-o'clock positions). Hips were treated as matched pairs, such that one hip from each specimen had all anchors placed from the MA portal and the other from the DALA portal. Allocation ensured an equal distribution of laterality between groups. After anchor insertion, specimens underwent computed tomography and dissection for further evaluation. RESULTS: Rim accessibility was similar between the groups; anchor insertion was most difficult at the 9-o'clock position, particularly with the MA portal technique, where only 50% (8/16) of attempts were successful, in comparison to the DALA portal technique, where 75% (12/16) of attempts were successful. Additionally, the 4-o'clock position proved challenging to access with the DALA portal technique, where only 75% (12/16) of attempts were successful, compared with 100% with the MA portal technique. The difference in accessibility of these techniques, however, did not reach statistical significance at the 9-o'clock position ( P = .2734) or 4-o'clock position ( P = .1012). Articular surface perforation occurred in 4.48% of all anchor insertion attempts, most commonly at the 3-o'clock position ( P = .0242). From the MA portal, 4.00% (4/100) perforated the joint, compared with 4.95% (5/101) from the DALA portal ( P > .999). Further, there were no significant differences in perforation rates at each location between the techniques ( P > .999). Psoas tunnel perforation occurred in 7.69% of all anchor insertion attempts between 2 and 4 o'clock, with equal rates at each location ( P ≥ .6606). From the MA portal, 4.17% (2/48) perforated the psoas tunnel, compared with 11.63% (5/43) from the DALA portal ( P ≥ .2486). Further, there were no significant differences at each location between the techniques ( P ≥ .4839). There was no association between acetabular version, femoral version, or lateral center-edge angle (LCEA) and articular surface or psoas tunnel perforation, regardless of portal use. CONCLUSION: Anchor insertion from either the MA or DALA portal appears to confer similar rim access and rates of articular surface or psoas tunnel perforation, with a cumulative rate of 4.48% and 7.69%, respectively. Rates of perforation did not differ between the portals and were not associated with acetabular or femoral version or LCEA. CLINICAL RELEVANCE: Caution should be employed when inserting anchors for labral refixation, particularly in anterior and medial locations (2-4 o'clock), as articular surface and psoas tunnel perforation may occur at a rate higher than previously anticipated. Portal selection does not appear to influence these outcomes.

Total Ankle Arthroplasty: An Imaging Overview.

With advances in implant technology, total ankle arthroplasty (TAA) has become an increasingly popular alternative to arthrodesis for the management of end-stage ankle arthritis. However, reports in the literature do not focus on the imaging features of TAA. Through a literature review, we demonstrate basic design features of the current ankle arthroplasty system, and the normal and abnormal postoperative imaging features associated with such devices. Pre- and postoperative evaluations of ankle arthroplasty mainly include radiography; in addition, computed tomography and magnetic resonance imaging provide further characterization of imaging abnormalities. Familiarization with multimodal imaging features of frequent procedural complications at various postoperative intervals is important in radiological practice.

MRI for the preoperative evaluation of femoroacetabular impingement.

Femoroacetabular impingement (FAI) refers to a condition characterized by impingement of the femoral head-neck junction against the acetabular rim, often due to underlying osseous and/or soft tissue morphological abnormalities. It is a common cause of hip pain and limited range of motion in young and middle-aged adults. Hip preservation surgery aims to correct the morphological variants seen in FAI, thereby relieving pain and improving function, and potentially preventing early osteoarthritis. The purpose of this article is to review the mechanisms of chondral and labral injury in FAI to facilitate an understanding of patterns of chondrolabral injury seen on MRI. Preoperative MRI evaluation of FAI should include assessment of osseous morphologic abnormalities, labral tears, cartilage status, and other associated compensatory injuries of the pelvis. As advanced chondral wear is the major relative contraindication for hip preservation surgery, MRI is useful in the selection of patients likely to benefit from surgery. Teaching points • The most common anatomical osseous abnormalities predisposing to FAI include cam and pincer lesions. • Morphological abnormalities, labral lesions, and cartilage status should be assessed. • In cam impingement, chondral wear most commonly occurs anterosuperiorly.• Pre-existing advanced osteoarthritis is the strongest predictor of poor outcomes after FAI surgery. • Injury to muscles and tendons or other pelvic structures can coexist with FAI.

The Prevalence of Pisotriquetral Arthritis in the Setting of Scapholunate Advanced Collapse.

Background Previous authors have reported pisotriquetral pain and subsequent pisiform excision following partial or total wrist fusion in patients with scapholunate advanced collapse (SLAC). Prior studies have not considered the potential role of SLAC biomechanics on pisotriquetral osteoarthritis (PT OA) development preoperatively. Purpose To determine the prevalence and severity of PT OA in patients with SLAC as compared with a control population. Patients and Methods Magnetic resonance imaging (MRI) studies of 24 patients with SLAC wrist and 24 sex- and age-matched control patients were analyzed. Patients with SLAC wrist were selected from a database of all wrist MRI studies performed at our institution from 2006 to 2015, excluding those with inflammatory arthritis, chondrocalcinosis, and incomplete or atraumatic scapholunate interosseous ligament rupture. Control patients underwent MRI for nonarthritic clinical indications and were chosen in an age- and sex-matched fashion. Patients undergoing MRI for triangular fibrocartilage complex injury, extensor carpi ulnaris tendinopathy, or ulnar-sided wrist pain were excluded from the control cohort. MRI grading of arthritic change at the pisotriquetral joint was assessed by a blinded musculoskeletal radiologist according to a four-category scale, with grade 4 indicating the greatest arthritic severity. Results The prevalence of PT OA in the control cohort was found to be 37.5% compared with 41.7% in the SLAC cohort. The prevalence of greatest arthritic severity (grade 4) at the pisotriquetral joint was found to be 4.2% in the control cohort, compared with 16.7% in the SLAC cohort. Conclusion We conclude that the overall prevalence of chondral wear at the pisotriquetral joint in SLAC wrist does not differ significantly from that found in control populations. We did identify a fourfold (but not statistically significant) increased prevalence of end-stage arthritis in patients with SLAC. Given reports of symptomatic PT OA developed following four-corner arthrodesis, we recommend preoperative vigilance for pisotriquetral pain in patients with SLAC arthritis. Level of Evidence Prognostic level III.

Diagnosis of gastrointestinal bleeding: A practical guide for clinicians.

Gastrointestinal bleeding is a common problem encountered in the emergency department and in the primary care setting. Acute or overt gastrointestinal bleeding is visible in the form of hematemesis, melena or hematochezia. Chronic or occult gastrointestinal bleeding is not apparent to the patient and usually presents as positive fecal occult blood or iron deficiency anemia. Obscure gastrointestinal bleeding is recurrent bleeding when the source remains unidentified after upper endoscopy and colonoscopic evaluation and is usually from the small intestine. Accurate clinical diagnosis is crucial and guides definitive investigations and interventions. This review summarizes the overall diagnostic approach to gastrointestinal bleeding and provides a practical guide for clinicians.

Diagnostic Accuracy of Imaging Modalities in the Evaluation of Vascular Invasion in Pancreatic Adenocarcinoma: A Meta-Analysis.

BACKGROUND: The extent of vascular invasion is a key factor determining the resectability of non-metastatic pancreatic adenocarcinoma. The purpose of this study is to determine the diagnostic accuracy of computed tomography (CT), endoscopic ultrasound (EUS), and magnetic resonance imaging (MRI) in the pre-operative evaluation of vascular invasion in pancreatic adenocarcinoma, with surgery as the reference standard. METHODS: A search of the MEDLINE database for relevant articles in the English language published between January 2000 and February 2009 was performed. From each study, 2 × 2 tables were obtained, and pooled sensitivity, specificity, positive likelihood ratios, negative likelihood ratios and diagnostic odds ratios were calculated for each modality, along with a summary receiver operating characteristics (SROC) curve. RESULTS: 16 studies with a total of 797 patients who had surgical assessment of vascular invasion were included in the analysis. Several studies evaluated more than one imaging modality, allowing 24 datasets to be obtained in total. Sensitivity was highest for CT (0.73, 95% CI 0.67 - 0.79), followed by EUS (0.66, 95% CI 0.56 - 0.75) and MRI (0.63, 95% CI 0.48 - 0.77). The specificity for all three imaging modalities was comparable. The diagnostic odds ratios for CT, EUS and MRI were 45.9 (95% CI 18.0 - 117.4), 23.0 (95%CI 9.4 - 56.6), 23.9 (95% CI 5.4 - 105.1) respectively. CONCLUSION: CT was more accurate than EUS and MRI in the evaluation of vascular invasion in pancreatic adenocarcinoma and should be the first line investigation in pre-operative staging.