Utility of a 2D kinematic HASTE sequence in magnetic resonance imaging assessment of adjacent segment degeneration following anterior cervical discectomy and fusion.

OBJECTIVES: To evaluate a dynamic half-Fourier acquired single turbo spin echo (HASTE) sequence following anterior cervical discectomy and fusion (ACDF) at the junctional level for adjacent segment degeneration comparing dynamic listhesis to radiographs and assessing dynamic cord contact and deformity during flexion-extension METHODS: Patients with ACDF referred for cervical spine MRI underwent a kinematic flexion-extension sagittal 2D HASTE sequence in addition to routine sequences. Images were independently reviewed by three radiologists for static/dynamic listhesis, and compared to flexion-extension radiographs. Blinded assessment of the HASTE sequence was performed for cord contact/deformity between neutral, flexion, and extension, to evaluate concordance between readers and inter-modality agreement. Inter-reader agreement for dynamic listhesis and impingement grade and inter-modality agreement for dynamic listhesis on MRI and radiographs was assessed using the kappa coefficient and percentage concordance. RESULTS: A total of 28 patients, mean age 60.2 years, were included. Mean HASTE acquisition time was 42 s. 14.3% demonstrated high grade dynamic stenosis (> grade 4) at the adjacent segment. There was substantial agreement for dynamic cord impingement with 70.2% concordance (kappa = 0.62). Concordance across readers for dynamic listhesis using HASTE was 81.0% (68/84) (kappa = 0.16) compared with 71.4% (60/84) (kappa = 0.40) for radiographs. Inter-modality agreement between flexion-extension radiographs and MRI assessment for dynamic listhesis across the readers was moderate (kappa = 0.41; 95% confidence interval: 0.16 to 0.67). CONCLUSIONS: A sagittal flexion-extension HASTE cine sequence provides substantial agreement between readers for dynamic cord deformity and moderate agreement between radiographs and MRI for dynamic listhesis. CLINICAL RELEVANCE STATEMENT: Degeneration of the adjacent segment with instability and myelopathy is one of the most common causes of pain and neurological deterioration requiring re-operation following cervical fusion surgery. KEY POINTS: • A real-time kinematic 2D sagittal HASTE flexion-extension sequence can be used to assess for dynamic listhesis, cervical cord, contact and deformity. • The additional kinematic cine sequence was well tolerated and the mean acquisition time for the 2D HASTE sequence was 42 s (range 31-44 s). • A sagittal flexion-extension HASTE cine sequence provides substantial agreement between readers for dynamic cord deformity and moderate agreement between radiographs and MRI for dynamic listhesis.

Utility of MRI for Patients 45 Years Old and Older With Hip or Knee Pain: A Systematic Review.

BACKGROUND. MRI utility for patients 45 years old and older with hip or knee pain is not well established. OBJECTIVE. We performed this systematic review to assess whether MRI-diagnosed hip or knee pathology in patients 45 years old and older correlates with symptoms or benefits from arthroscopic surgery. EVIDENCE ACQUISITION. A literature search (PubMed, Web of Science, Embase) of articles published before October 3, 2022, was performed to identify original research pertaining to the study question. Publication information, study design, cohort size, osteoarthritis severity, age (range, mean), measured outcomes, minimum follow-up length, and MRI field strength were extracted. Study methods were appraised with NIH's study quality assessment tools. EVIDENCE SYNTHESIS. The search yielded 1125 potential studies, of which 31 met the inclusion criteria (18 knee, 13 hip). Knee studies (10 prospective, eight retrospective) included 5907 patients (age range, 45-90 years). Bone marrow edema-like lesions, joint effusions, and synovitis on MRI were associated with symptoms. In patients with osteoarthritis, meniscal tears were less likely to be symptom generators and were less likely to respond to arthroscopic surgery with osteoarthritis progression. Hip studies (11 retrospective, two prospective) included 6385 patients (age range, 50 to ≥ 85 years). Patients with Tönnis grade 2 osteoarthritis and lower with and without femoroacetabular impingement (FAI) showed improved outcomes after arthroscopy, suggesting a role for MRI in the diagnosis of labral tears, chondral lesions, and FAI. Although this group benefited from arthroscopic surgery, outcomes were inferior to those in younger patients. Variability in study characteristics, follow-up, and outcome measures precluded a meta-analysis. CONCLUSION. In patients 45 years old and older, several knee structural lesions on MRI correlated with symptoms, representing potential imaging biomarkers. Meniscal tear identification on MRI likely has diminished clinical value as osteoarthritis progresses. For the hip, MRI can play a role in the diagnosis of labral tears, chondral lesions, and FAI in patients without advanced osteoarthritis. CLINICAL IMPACT. Several structural lesions on knee MRI correlating with symptoms may represent imaging biomarkers used as treatment targets. Osteoarthritis, not age, may play the greatest role in determining the utility of MRI for patients 45 years old and older with hip or knee pain.

Sclerosing well-differentiated liposarcoma: two diagnostically challenging mimicker cases and a literature review.

Liposarcoma is a malignant soft tissue tumor with several subtypes, the most common of which is well-differentiated liposarcoma (WDL) or atypical lipomatous tumor (ALT). WDL/ALTs are further divided into three histological subtypes, including lipoma-like, sclerosing, and inflammatory. While the majority of these tumors are predominantly fatty, the sclerosing variant demonstrates diverse histologic and radiographic characteristics, including variable amounts of fibrosis and fat. Because of this histological variability and relative rarity, the sclerosing WDL/ALT can present diagnostic dilemmas. We present two cases of sclerosing WDL/ALT, both of which demonstrated high degrees of fibrosis and a paucity of fat, mimicking desmoid fibromatosis and other fibrotic soft tissue tumors. Thus, it is important for radiologists to be aware of the subtypes of liposarcoma and their unique characteristics, and to consider sclerosing WDL/ALT in cases of fibrotic soft tissue tumors.

Assessment of fatty infiltration of the hamstring muscles in chronic proximal hamstring ruptures and effect on clinical outcomes after surgical repair: a novel application of the Goutallier classification.

INTRODUCTION: Increased time to surgery has been previously associated with poorer clinical outcomes after surgical treatment of proximal hamstring ruptures, though the etiology remains unclear. The purpose of this study was to evaluate whether degree of muscle atrophy, as assessed using the Goutallier classification system, is associated with worse outcomes following surgical treatment of chronic proximal hamstring ruptures. MATERIALS AND METHODS: This was a retrospective case series of patients who underwent repair of proximal hamstring ruptures from 2012 to 2020 with minimum 2-year follow-up. Patients were included if they underwent primary repair of a proximal hamstring rupture ≥ 6 weeks after the date of injury and had accessible preoperative magnetic resonance imaging (MRI). Exclusion criteria were allograft reconstruction, endoscopic repair, or prior ipsilateral hip surgery. Patients were administered validated surveys: the modified Harris Hip Score (mHHS) and Perth Hamstring Assessment Tool (PHAT). Fatty atrophy on preoperative MRI was independently graded by two musculoskeletal radiologists using the Goutallier classification. Multivariate regression analysis was performed to evaluate associations of preoperative characteristics with muscle atrophy, as well as mHHS and PHAT scores. RESULTS: Complete data sets were obtained for 27 patients. A majority of this cohort was male (63.0%), with a mean age of 51.5 ± 11.8 years and BMI of 26.3 ± 3.8. The mean follow-up time was 62.6 ± 23.1 months, and the mean time from injury-to-surgery was 20.4 ± 15.3 weeks. The Goutallier grading inter-reader weighted kappa coefficient was 0.655. Regression analysis demonstrated that atrophy was not significantly associated with PHAT (p = 0.542) or mHHS (p = 0.574) at latest follow-up. Increased age was significantly predictive of muscle atrophy (ß = 0.62, p = 0.005) and was also found to be a significant predictor of poorer mHHS (ß = - 0.75; p = 0.037). CONCLUSIONS: The degree of atrophy was not found to be an independent predictor of clinical outcomes following repair of chronic proximal hamstring ruptures. Increasing age was significantly predictive of increased atrophy and poorer patient-reported outcomes.

Deep Learning Reconstruction Enables Prospectively Accelerated Clinical Knee MRI.

Background MRI is a powerful diagnostic tool with a long acquisition time. Recently, deep learning (DL) methods have provided accelerated high-quality image reconstructions from undersampled data, but it is unclear if DL image reconstruction can be reliably translated to everyday clinical practice. Purpose To determine the diagnostic equivalence of prospectively accelerated DL-reconstructed knee MRI compared with conventional accelerated MRI for evaluating internal derangement of the knee in a clinical setting. Materials and Methods A DL reconstruction model was trained with images from 298 clinical 3-T knee examinations. In a prospective analysis, patients clinically referred for knee MRI underwent a conventional accelerated knee MRI protocol at 3 T followed by an accelerated DL protocol between January 2020 and February 2021. The equivalence of the DL reconstruction of the images relative to the conventional images for the detection of an abnormality was assessed in terms of interchangeability. Each examination was reviewed by six musculoskeletal radiologists. Analyses pertaining to the detection of meniscal or ligament tears and bone marrow or cartilage abnormalities were based on four-point ordinal scores for the likelihood of an abnormality. Additionally, the protocols were compared with use of four-point ordinal scores for each aspect of image quality: overall image quality, presence of artifacts, sharpness, and signal-to-noise ratio. Results A total of 170 participants (mean age ± SD, 45 years ± 16; 76 men) were evaluated. The DL-reconstructed images were determined to be of diagnostic equivalence with the conventional images for detection of abnormalities. The overall image quality score, averaged over six readers, was significantly better (P < .001) for the DL than for the conventional images. Conclusion In a clinical setting, deep learning reconstruction enabled a nearly twofold reduction in scan time for a knee MRI and was diagnostically equivalent with the conventional protocol. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Roemer in this issue.

Imaging approach to prosthetic joint infection.

The diagnosis of prosthetic joint infection (PJI) remains challenging, despite multiple available laboratory tests for both serum and synovial fluid analysis. The clinical symptoms of PJI are not always characteristic, particularly in the chronic phase, and there is often significant overlap in symptoms with non-infectious forms of arthroplasty failure. Further exacerbating this challenge is lack of a universally accepted definition for PJI, with publications from multiple professional societies citing different diagnostic criteria. While not included in many of the major societies' guidelines for diagnosis of PJI, diagnostic imaging can play an important role in the workup of suspected PJI. In this article, we will review an approach to diagnostic imaging modalities (radiography, ultrasound, CT, MRI) in the workup of suspected PJI, with special attention to the limitations and benefits of each modality. We will also discuss the role that image-guided interventions play in the workup of these patients, through ultrasound and fluoroscopically guided joint aspirations. While there is no standard imaging algorithm that can universally applied to all patients with suspected PJI, we will discuss a general approach to diagnostic imaging and image-guided intervention in this clinical scenario.

Imaging features and biopsy yield of soft tissue metastatic lesions: 10-year single tertiary center experience.

OBJECTIVE: To evaluate imaging features of soft tissue metastases, technical factors associated with diagnostic yield of image-guided biopsy, and clinical impact of biopsy results on patient outcomes. MATERIALS AND METHODS: A total of 1605 image-guided soft tissue biopsies were retrospectively identified from December 2010 to December 2020. Included lesions were histologically proven musculoskeletal soft tissue metastases. Lesions were excluded if intraabdominal, intrathoracic, retroperitoneal, associated with osseous lesions or surgical scar implants or arising from skin or lymph nodes. Image guidance modality, needle size, number of cores, and lesion location, size, and depth from skin were recorded. Patient demographics, malignancy history, biopsy-driven changes in management, and survival rate after biopsy were collected. RESULTS: Forty-six patients met the inclusion criteria with a biopsy diagnostic yield of 44/46 (95.7%). Metastases were most commonly located truncal (82.6%, p < 0.001) and intramuscular (78.3%, p < 0.001). A total of 37/46 (80.4%) biopsies were US-guided. And 9/46 (19.6%) were CT-guided. There was no significant difference in the number of cores or mean needle gauge between diagnostic and nondiagnostic biopsies. At time of review, 23 (50%) patients were deceased, with a mean survival of 13.5 months after biopsy. The majority (71.7%) of patients had a known primary malignancy at time of biopsy, most commonly lung (24.2%) and breast (24.2%). Overall survival showed no association with anatomic location (p > 0.83) or tissue type (p > 0.34). The most common biopsy-driven outcome was initiation of chemotherapy, immunotherapy, and/or radiotherapy (52.2%). CONCLUSION: Image-guided biopsy for soft tissue metastases has high diagnostic yield and commonly influences clinical management. Metastases were most commonly intramuscular in the trunk and are associated with poor prognosis.

Patients With Low-Grade Lumbosacral Transitional Vertebrae Demonstrate No Difference in Achievement of Clinical Thresholds After Hip Arthroscopy for Femoroacetabular Impingement Syndrome.

PURPOSE: To compare clinical outcomes at 2 years following primary hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) between patients with and without low-grade lumbosacral transitional vertebra (LSTV). METHODS: We performed a retrospective matched-cohort analysis of patients who underwent primary HA for FAIS from 2011 to 2018 with minimum 2-year follow-up. LSTV was graded on preoperative radiographs using the Castellvi classification. Patients with grades I and II LSTV were matched 1:1 with controls on age, sex, and body mass index. Radiographic markers of FAIS morphology were measured. Pre- to postoperative improvement in the modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS) as well as 2-year achievement rates for the minimum clinically-important difference, substantial clinical benefit, and patient acceptable symptom state were compared between patients with versus without LSTV. The Wilcoxon signed-rank test was used for intergroup mean comparisons and the Cochran-Mantel-Haenszel test for categorical variables. RESULTS: In total, 58 patients with LSTV were matched to 58 controls. Among LSTV patients, 48 were Castellvi type 1 (82.8%) and 32 (55.2%) had bilateral findings. No significant differences were found between groups with respect to radiographic markers of FAIS, including alpha angle (P = .88), lateral center edge angle (P = .42), or crossover sign (P = .71). Although patients with LSTV had greater improvement in NAHS at 2-year follow-up compared with control patients (P = .04), there were no significant differences in modified Harris Hip Score improvement (P = .31) or achievement of the minimum clinically-important difference (P = .73), substantial clinical benefit (P = .61), or patient acceptable symptom state (P = .16). CONCLUSIONS: Patients with low-grade LSTV had greater 2-year improvement in NAHS than controls, whereas no significant differences were observed in achievement of clinical thresholds at 2-year follow-up. There were no differences between groups with respect to any measured radiographic markers of FAIS morphology. Importantly, the findings of this study are underpowered and should be viewed with caution in the greater context of the LSTV literature. LEVEL OF EVIDENCE: Level III; retrospective comparative study.

Decreased Hip Labral Width Measured on Preoperative Magnetic Resonance Imaging Is Associated With Greater Revision Rate After Primary Arthroscopic Labral Repair for Femoroacetabular Impingement Syndrome at 5-Year Follow-Up.

PURPOSE: To examine the associations between hip labral width and patient-reported outcomes, clinical threshold achievement rates, and rate of reoperation among patients with femoroacetabular impingement syndrome (FAIS) who underwent hip arthroscopy and labral repair at minimum 5-year follow-up. METHODS: Patients were identified from a prospective database who underwent primary hip arthroscopy for treatment of labral tears and FAIS. Modified Harris Hip Score (mHHS) and Nonarthritic Hip Score (NAHS) were recorded preoperatively and at 5-year follow-up. Achievement of the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient-acceptable symptom state (PASS) was determined using previously established values. Labral width magnetic resonance imaging measurements were performed by 2 independent readers at standardized "clockface" locations. Patients were stratified into 3 groups at each position: lower-width (<½ SD below mean), middle-width (within ½ SD of mean), and upper-width (>½ SD above mean). Multivariable regression was used to evaluate associations of labral width with patient-reported outcomes and reoperation rate. RESULTS: Seventy-three patients (age: 41.0 ± 12.0 years; 68.5% female) were included. Inter-rater reliability for labral width measurements was high at all positions (intraclass correlation coefficient 0.94-0.96). There were no significant intergroup differences in mHHS/NAHS improvement (P > .05) or in achievement rates of MCID/SCB/PASS at each clockface position (P > .05). Eleven patients (15.1%) underwent arthroscopic revision and 4 patients (5.5%) converted to total hip arthroplasty. Multivariable analysis found lower-width groups at 11:30 (odds ratio 1.75, P = .02) and 3:00 (odds ratio 1.59, P = .04) positions to have increased odds of revision within 5 years; however, labral width was not associated with 5-year improvement in mHHS/NAHS, achievement of MCID/PASS/SCB, or conversion to total hip arthroplasty (P > .05). CONCLUSIONS: Hip labral width <½ SD below the mean measured on preoperative magnetic resonance imaging at 11:30- and 3:00-clockface positions was associated with increased odds of reoperation after arthroscopic labral repair and treatment of FAIS. Labral width was not associated with 5-year improvement of mHHS, NAHS, achievement of clinical thresholds, or conversion to arthroplasty. LEVEL OF EVIDENCE: Level IV, case series.

Postoperative Musculoskeletal Imaging and Interventions Following Hip Preservation Surgery, Deformity Correction, and Hip Arthroplasty.

Total hip arthroplasty and hip preservation surgeries have substantially increased over the past few decades. Musculoskeletal imaging and interventions are cornerstones of comprehensive postoperative care and surveillance in patients undergoing established and more recently introduced hip surgeries. Hence the radiologist's role continues to evolve and expand. A strong understanding of hip joint anatomy and biomechanics, surgical procedures, expected normal postoperative imaging appearances, and postoperative complications ensures accurate imaging interpretation, intervention, and optimal patient care. This article presents surgical principles and procedural details pertinent to postoperative imaging evaluation strategies after common hip surgeries, such as radiography, ultrasonography, computed tomography, and magnetic resonance imaging. We review and illustrate the expected postoperative imaging appearances and complications following chondrolabral repair, acetabuloplasty, osteochondroplasty, periacetabular osteotomy, realigning and derotational femoral osteotomies, and hip arthroplasty.

Likelihood of hip infection with image-guided hip aspiration dry tap: a 10-year retrospective study.

OBJECTIVE: To determine the rate of infection in patients with suspected hip septic arthritis who underwent image-guided aspiration (IHA) resulting in dry-tap, diagnostic value of subsequent lavage and re-aspiration, and if pre-aspiration MRI can help prevent a dry tap. MATERIALS AND METHODS: Retrospective review between 2010 to 2020 identified native hip (NH) and total hip arthroplasty (THA) patients who had a dry-tap following aspiration for suspected infection or periprosthetic joint infection (PJI). Serology tests, lavage/re-aspiration volumes, and aspirate cell-count/culture were assessed. On pre-aspiration MRI, presence/grade of joint effusion (JE), pseudocapsule dehiscence (PD), extraarticular fluid and sinus-tract were recorded. RESULTS: Out of 215 included dry-taps, 185 (86.0%) were non-infected and 30 (13.9%) infected. In subgroup analysis, 64/71(90.1%) NH and 121/144(84.0%) THA dry-taps were non-infected. Pre-aspiration MRI of THA group with dry-tap showed significant findings; PD with extraarticular fluid (8/12, 66.7%) and sinus tract (7/12, 58.3%) were higher in the infected compared to non-infected group (5/42, 11.9% and 0/42, 0.0%) (both p < 0.001). Among THA group, polymorphonuclear-leukocytes > 80% was present in 8/9 (88.9%) of infected versus 4/28 (14.3%) non-infected group (p < 0.001). Multivariable regression showed PD (p = 0.005) and JE (p = 0.042) being significant independent predictors of PJI, similarly the elevated CRP (p = 0.044) and JE (p = 0.017). CONCLUSION: Majority of patients suspected of hip joint infection with dry-tap were non-infected. Synovial PMN% following lavage maintains high sensitivity for detection of PJI. In patients with THA, PD and subsequent extraarticular collection can be associated with dry-tap therefore, pre-aspiration MRI can help determine their presence and plan the aspiration.

3D-MRI versus 3D-CT in the evaluation of glenoid deformity in glenohumeral arthritis using Dixon 3D FLASH sequence.

OBJECTIVE: To compare MRI with 3D reconstructions and 3D-CT with respect to assessment of glenoid wear in osteoarthritic shoulders. METHODS: 3D reconstructions were generated for CT and MR (utilizing the Dixon technique) imaging performed on 29 osteoarthritic shoulders. Two reviewers independently performed glenoid morphometric measurements and evaluated glenoid erosion. Mean differences between the two modalities were calculated. Inter-observer agreement was calculated using kappa coefficient. RESULTS: The combined mean absolute difference (bias) in glenoid version between 3D-CT and 3D-MRI was 2.7° ± 1.6° (range 0.15-7.85, P value = 0.7). The combined mean absolute difference in glenoid inclination between 3D-CT and 3D-MRI was 6.8° ± 4.1° (range 0.8°-15.75°, P value = 0.17). No significant inter-reader variation in glenoid version and inclination measurements on 3D-CT and 3D-MRI was found (P > 0.05). The inter-reader reliability for both CT and MRI was high for Walch grading of glenoid bone loss (κ = 1, κ = 0.81, respectively). CONCLUSIONS: 3D-MRI is comparable to 3D-CT with respect to axial glenoid bone loss, as measured by glenoid version. However, for coronal bone loss estimation, measured by glenoid inclination, 3D-CT remains the gold standard. Thus, 3D-MR can be used as an alternative for preoperative assessment of glenoid version in arthritic shoulders.

Society of Skeletal Radiology- white paper. Guidelines for the diagnostic management of incidental solitary bone lesions on CT and MRI in adults: bone reporting and data system (Bone-RADS).

The purpose of this article is to present algorithms for the diagnostic management of solitary bone lesions incidentally encountered on computed tomography (CT) and magnetic resonance (MRI) in adults. Based on review of the current literature and expert opinion, the Practice Guidelines and Technical Standards Committee of the Society of Skeletal Radiology (SSR) proposes a bone reporting and data system (Bone-RADS) for incidentally encountered solitary bone lesions on CT and MRI with four possible diagnostic management recommendations (Bone-RADS1, leave alone; Bone-RADS2, perform different imaging modality; Bone-RADS3, perform follow-up imaging; Bone-RADS4, biopsy and/or oncologic referral). Two algorithms for CT based on lesion density (lucent or sclerotic/mixed) and two for MRI allow the user to arrive at a specific Bone-RADS management recommendation. Representative cases are provided to illustrate the usability of the algorithms.

Does Sacrococcygeal Skeletal Morphology and Morphometry Influence Pressure Injury Formation in Adults?

GENERAL PURPOSE: To present a study that investigated sacrococcygeal skeletal structure as a possible nonmodifiable intrinsic risk factor for pressure injury and identify possible issues caused by its morphology. TARGET AUDIENCE: This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care. LEARNING OBJECTIVES/OUTCOMES: After participating in this educational activity, the participant will:1. Recognize the background information the authors considered when planning and conducting their study of sacrococcygeal skeletal structure as a possible pressure injury risk factor.2. Identify the characteristics of the two groups of study participants.3. Choose the results of the study clinicians may consider when implementing evidence-based practice.

To determine if sacrococcygeal skeletal morphology and morphometry characteristics were possible pressure injury (PI) intrinsic risk factors; determine the exact location of these PIs; and generate hypotheses and determine methodological considerations required for future larger studies. This case-control pilot study compared 30 patients who had an MRI scan­15 patients had a PI and 15 patients did not. Key sacrococcygeal morphology and morphometry parameters were assessed. On average, patients with PIs had less of a lumbosacral and sacrococcygeal angle and a greater sacral curvature and intercoccygeal angle than did patients without a PI. Patients with PIs had more variable coccyx types. Tissue and bone destruction precluded several measurements in some patients. The most common area of destruction was located distally. Sacrococcygeal measurements differed in patients with PIs, and PIs were predominately located distally. Authors recommend replicating this study on a larger scale because certain key attributes warrant further investigation to determine their influence on sacrococcygeal PIs. Sacrococcygeal morphology and morphometry parameters have not been previously studied as possible intrinsic risk factors for PIs; yet, this is the most common location for their occurrence. Knowledge regarding possible injury mechanisms due to the forces from overlying skeletal structures with respective tissue loading over the sacrococcygeal area has the potential to inform practice; preventive strategies; and equipment, products, and technology developed.

Fibular Tip Periostitis: New Radiographic Sign Predictive of Chronic Peroneal Tendon Subluxation-Dislocation in Pes Planovalgus.

BACKGROUND. Tearing of the superior peroneal retinaculum is a known cause of peroneal tendon subluxation-dislocation. However, with the exception of cortical avulsions at the fibular attachment, superior peroneal retinaculum injury and subsequent peroneal tendon subluxation-dislocation are typically radiographically occult. OBJECTIVE. The purpose of this study was to evaluate the previously undescribed association between radiographic fibular tip periostitis and MRI evidence of peroneal tendon subluxation-dislocation in patients with hindfoot valgus. METHODS. Thirty-five patients with radiographic fibular tip periostitis and 35 ageand sex-matched individuals without periostitis were selected from among 220 consecutively registered patients with hindfoot valgus who had undergone both ankle radiography and MRI. Studies were retrospectively assessed by two musculoskeletal radiologists in consensus and by two additional blinded radiologists independently for the presence of peroneal tendon subluxation-dislocation, presence of subfibular impingement, and hindfoot valgus angle measurements. Interobserver agreement and accuracy, sensitivity, and specificity in the detection of fibular periostitis, peroneal tendon subluxation-dislocation, and subfibular impingement were calculated, and Fischer exact, Mann-Whitney, kappa coefficient, and intraclass correlation tests were performed. RESULTS. Both the consensus and the two independent interpretations showed that the frequency of peroneal tendon subluxation-dislocation was significantly greater in the group with periostitis (62.9%, 65.7%, and 85.7%) than in the group without periostitis (5.7%, 0%, and 14.3%) (p < .001). The finding of periostitis was specific and highly sensitive for predicting peroneal tendon subluxation-dislocation. The frequency of subfibular impingement was also statistically higher in the group with periostitis than in the group without it (p < .001). The hindfoot valgus angle was statistically larger in the group with periostitis than in the control group (p = .01-.002) and among patients with versus those without peroneal tendon subluxation-dislocation (p = .002 to p < .001). The blinded readers had substantial or almost perfect agreement on all imaging interpretations (concordance rate, 82.9-95.7%; κ = 0.66-0.91). CONCLUSION. The radiographic finding of fibular tip periostitis in patients with hindfoot valgus can be a predictor of peroneal tendon subluxation-dislocation and may also suggest advanced hindfoot valgus and subfibular impingement. These radiographic associations should be recognized by the radiologist, and MRI may be recommended as clinically indicated. CLINICAL IMPACT. Chronic undiagnosed peroneal tendon subluxation-dislocation can be a persistent cause of lateral ankle pain, leading to further degeneration and the possibility of complete peroneal tendon tears. Distal fibular periostitis in patients with hindfoot valgus can be a reliable radiographic indicator of this entity and may suggest the presence of subfibular impingement.

3D MRI Models of the Musculoskeletal System.

Computed tomography (CT) is most commonly used to produce three-dimensional (3D) models for evaluating bone and joint morphology in clinical practice. However, 3D models created from magnetic resonance imaging (MRI) data can be equally effective for comprehensive and accurate assessment of osseous and soft tissue structure morphology and pathology. The quality of 3D MRI models has steadily increased over time, with growing potential to replace 3D CT models in various musculoskeletal (MSK) applications. In practice, a single MRI examination for two-dimensional and 3D assessments can increase the value of MRI and simplify the pre- and postoperative imaging work-up. Multiple studies have shown excellent performance of 3D MRI models in shoulder injuries, in the hip in the setting of femoroacetabular impingement, and in the knee for the creation of bone surface models. Therefore, the utility of 3D MRI postprocessed models is expected to continue to rise and broaden in applications. Computer-based and artificial intelligence-assisted postprocessing techniques have tremendous potential to improve the efficiency of 3D model creation, opening many research avenues to validate the applicability of 3D MRI and establish 3D-specific quantitative assessment criteria. We provide a practice-focused overview of 3D MRI acquisition strategies, postprocessing techniques for 3D model creation, MSK applications of 3D MRI models, and an illustration of cases from our daily clinical practice.

Does Magnetic Resonance Imaging After Diagnostic Ultrasound for Soft Tissue Masses Change Clinical Management?

OBJECTIVES: To evaluate whether a follow-up magnetic resonance imaging (MRI) scan performed after initial ultrasound (US) to evaluate soft tissue mass (STM) lesions of the musculoskeletal system provides additional radiologic diagnostic information and alters clinical management. METHODS: A retrospective chart review was performed of patients undergoing initial US evaluations of STMs of the axial or appendicular skeleton between November 2012 and March 2019. Patients who underwent US examinations followed by MRI for the evaluation of STM lesions were identified. For inclusion, the subsequent pathologic correlation was required from either a surgical or image-guided biopsy. Imaging studies with pathologic correlations were then reviewed by 3 musculoskeletal radiologists, who were blinded to the pathologic diagnoses. The diagnostic utility of MRI was then assessed on the basis of a 5-point grading scale, and inter-reader agreements were determined by the Fleiss κ statistic. RESULTS: Ninety-two patients underwent MRI after US for STM evaluations. Final pathologic results were available in 42 cases. Samples were obtained by surgical excision or open biopsy (n = 34) or US-guided core biopsy (n = 8). The most common pathologic diagnoses were nerve sheath tumors (n = 9), lipomas (n = 5), and leiomyomas (n = 5). Imaging review showed that the subsequent MRI did not change the working diagnosis in 73% of cases, and the subsequent MRI was not considered to narrow the differential diagnosis in 68% of cases. There was slight inter-reader agreement for the diagnostic utility of MRI among individual cases (κ = 0.10) between the 3 readers. CONCLUSIONS: The recommendation of MRI to further evaluate STM lesions seen with US frequently fails to change the working diagnosis or provide significant diagnostic utility.

Pediatric versus adult magnetic resonance imaging patterns in acute high ankle sprains.

BACKGROUND: There is a paucity of literature describing MRI patterns of high ankle sprains in pediatric patients. Radiologists should understand MRI patterns of these injuries in both adults and children. OBJECTIVE: To describe normal MRI appearance of pediatric syndesmotic ligaments and compare MRI patterns of high ankle sprains in children versus adults. MATERIALS AND METHODS: We reviewed consecutive ankle MRIs performed over 3 years and divided them into three cohorts: a normal pediatric (≤16 years) cohort, and pediatric and adult cohorts with acute/subacute ankle syndesmosis injuries. Our retrospective review assessed interobserver agreement (Cohen kappa coefficient) and normal pediatric syndesmotic anatomy. We compared patterns of high ankle sprains (Fisher exact test) including ligament tears, periosteal stripping, avulsions and fractures. RESULTS: Of the 582 ankle MRIs, we included 25 in the normal pediatric cohort, 20 in the pediatric injury cohort and 23 in the adult injury cohort. The anterior and posterior tibiofibular ligaments all attached to cortex or cartilaginous precursor, while the interosseous ligament/membrane complex attached to the fibrous periosteum in 22/25 (88%) normal pediatric cases. Tibial periosteal stripping at the interosseous ligament/membrane complex attachment occurred in 7/20 (35%) pediatric and 1/23 (4%) adult injury cases (P=0.02). No other statistically significant differences were found. Interobserver agreement ranged from kappa=0.46 to kappa=0.82 (ligament tears), 0.38 to 0.45 (avulsions) and 0.69 to 0.77 (periosteal stripping). CONCLUSION: The normal interosseous ligament/membrane complex typically attaches to fibrous periosteum rather than bony cortex. Tibial periosteal stripping, usually without tibial fracture, is significantly more common among pediatric high ankle sprains. MRI patterns of high ankle sprains are otherwise not significantly different between children and adults.

Does image-guided biopsy of discitis-osteomyelitis provide meaningful information to impact clinical management?

OBJECTIVE: The aims of this study are to assess the diagnostic yield of image-guided biopsy for discitis-osteomyelitis (DO), identify factors associated with biopsy yield (laboratory, pre-defined MRI findings, and biopsy technique), and impact of biopsy on management of patients appropriately selected according to the Infectious Disease Society of America guidelines (IDSA). MATERIALS AND METHODS: This is a retrospective review of patients who underwent biopsy for suspected DO from 2011 to 2019. Reference standards to establish diagnosis of DO in order were histopathology/microbiology from biopsy or subsequent surgical sampling, positive blood culture or serology, and imaging/clinical follow-up. Laboratory markers, pre-biopsy antibiotics and MRI features, procedural-related variables, and impact of biopsy on management were assessed. Multivariable logistic regression was also performed. RESULTS: Out of 97 included patients, 78 were diagnosed with DO. Overall sensitivity of biopsy for detecting DO was 41.0% (32/78), including 10 patients with positive histopathology only, 14 with positive biopsy culture only, and 8 with both. Elevated ESR (p < 0.001) and epidural collection on MRI (p = 0.008) were associated with higher biopsy yield (63.6% and 68.6%, respectively) in a multivariable model. Procedural variables were not associated with yield. Biopsy results impacted the management in 19/77 (24.7%) patients, of whom 15/19 (78.9%) had treatment de-escalation and 4/19 (21.0%) had treatment escalation including starting new anti-tuberculous and anti-fungal regimens. CONCLUSION: Sensitivity of biopsy for detecting DO was 41.0%. When IDSA guidelines are followed, biopsy provided impactful information that changed the management in 24.7% of patients. Evaluation for elevated ESR and epidural collection can help improve yield and patient selection for biopsy.

Imaging-based patient-reported outcomes (PROs) database: How we do it.

Patient-reported outcomes (PROs) provide an essential understanding of the impact a condition or treatment has on a patient, while complementing other, more traditional outcomes information like survival and time to symptom resolution. PROs have become increasingly important in medicine with the push toward patient-centered care. The creation of a PROs database within an institution or practice provides a way to collect, understand, and use this kind of patient feedback to inform quality improvement and develop the evidence base for medical decision-making and on a larger scale could potentially help determine national standards of care and treatment guidelines. This paper provides a first-hand account of our experience setting up an imaging-based PROs database at our institution and is organized into steps the reader can follow for creating a PROs database of their own. Given the limited use of PROs within both diagnostic and interventional radiology, we hope our paper stimulates a new interest among radiologists who may have never considered outcomes work in the past.