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Musculoskeletal neoplasms include tumors arising from bone, cartilage, muscles, tendons, nerves, and synovium. After initial screening radiographs, magnetic resonance (MR) imaging is the mainstay of management, and its role continues to increase in both pre- and post-operative evaluations. This article presents a review of the available qualitative and quantitative MR techniques for evaluating musculoskeletal neoplasms, including conventional and advanced imaging techniques such as diffusion-weighted and diffusion-tensor imaging, chemical shift and Dixon imaging, dynamic contrast-enhanced MRI, neurography, and spectroscopy. After reading the article, radiologists and oncologists will be able to apply these principles in their practices to benefit patients with musculoskeletal neoplasms.

Purpose The single-session dose tolerance of the spinal nerves has been observed to be similar to that of the spinal cord in pigs, counter to the perception that peripheral nerves are more tolerant to radiation. This pilot study aims to obtain a first impression of the single-session dose-response of the brachial plexus using pigs as a model. Methods and Materials Ten Yucatan minipigs underwent computed tomography and magnetic resonance imaging for treatment planning, followed by single-session stereotactic ablative radiotherapy. A 2.5-cm length of the left-sided brachial plexus cords was irradiated. Pigs were distributed in 3 groups with prescription doses of 16 (n = 3), 19 (n = 4), and 22 Gy (n = 3). Neurologic status was assessed by observation for changes in gait and electrodiagnostic examination. Histopathologic examination was performed with light microscopy of paraffin-embedded sections stained with Luxol fast blue/periodic acid-Schiff and Masson's trichrome. Results Seven of the 10 pigs developed motor deficit to the front limb of the irradiated side, with a latency from 5 to 8 weeks after irradiation. Probit analysis of the maximum nerve dose yields an estimated ED50 of 19.3 Gy for neurologic deficit, but the number of animals was insufficient to estimate 95% confidence intervals. No motor deficits were observed at a maximum dose of 17.6 Gy for any pig. Nerve conduction studies showed an absence of sensory response in all responders and absent or low motor response in most of the responders (71%). All symptomatic pigs showed histologic lesions to the left-sided plexus consistent with radiation-induced neuropathy. Conclusions The single-session ED50 for symptomatic plexopathy in Yucatan minipigs after irradiation of a 2.5-cm length of the brachial plexus cords was determined to be 19.3 Gy. The dose-response curve overlaps that of the spinal nerves and the spinal cord in the same animal model. The relationship between the brachial plexus tolerance in pigs and humans is unknown, and caution is warranted when extrapolating for clinical use.

Background Data describing the effect of obesity on antitumor necrosis factor (anti-TNF) treatment response are inconsistent. Visceral adipose tissue (VAT) is a superior marker of adiposity to body mass index. However, its effect on treatment response is unclear. We aimed to evaluate the effect of VAT on anti-TNF treatment response. Methods Inflammatory bowel disease (IBD) patients starting anti-TNF agents between January 1, 2009, and July 31, 2019, were included. 3-dimensional measurements of VAT volume and visceral fat index (visceral:subcutaneous adipose tissue ratio; VFI) were obtained from computed tomography (CT) scans. Subjects were categorized by predefined volume cutoffs ( Results The final cohort included 176 patients. No significant differences in treatment response at 6 months was observed. At 12 months, compared with volume Conclusions We found VAT volume is associated with anti-TNF treatment response in a nondose dependent manner, and VFI may inform risk of surgery after anti-TNF initiation. If confirmed by prospective studies, VAT volumetrics are potentially useful biomarkers to inform IBD treatment decisions.

As quality and cost effectiveness become essential in clinical practice, an evidence-based evaluation of the utility of imaging orders becomes an important consideration for radiology’s value in patient care. We report an institutional quality improvement project including a retrospective review of utility of sacrum magnetic resonance (MR) imaging for low back pain at our institution over a four-year period and follow-up results after physician education intervention. Sacral MR imaging for low back pain and tailbone pain were only positive for major findings in 2/98 (2%) cases, and no major changes in patient management related to imaging findings occurred over this period, resulting in almost $500000 cost without significant patient benefit. We distributed these results to the Family Medicine department and clinics that frequently placed this order. An approximately 83% drop in ordering rate occurred over the ensuing 3 mo follow-up period. Sacrum MR imaging for low back pain and tail bone pain has not been a cost-effective diagnostic tool at our institution. Physician education was a useful tool in reducing overutilization of this study, with a remarkable drop in such studies after sharing these findings with primary care physicians at the institution. In conclusion, sacrum MR imaging rarely elucidates the cause of low back/tail pain diagnosed in a primary care setting and is even less likely to result in major changes in management. The practice can be adopted in other institutions for the benefit of their patients and improve cost efficiency.

OBJECTIVE To develop and validate an Osseous Tumor Reporting and Data System (OT-RADS) with the hypothesis that the proposed guideline is reliable and assists in separating benign from malignant osseous tumors with a good area under the curve, and that could assist further patient management. METHODS In this multireader cross-sectional validation study, an agreement was reached for OT-RADS categories based on previously described magnetic resonance imaging features and consensus of expert musculoskeletal radiologists. World Health Organization classification was used, and a wide spectrum of benign and malignant osseous tumors was evaluated. Magnetic resonance imaging categories were as follows: OT-RADS 0-incomplete imaging; OT-RADS I-negative; OT-RADS II-definitely benign; OT-RADS III-probably benign; OT-RADS IV-suspicious for malignancy or indeterminate; OT-RADS V-highly suggestive of malignancy; and OT-RADS VI-known biopsy-proven malignancy or recurrent malignancy in the tumor bed. Four blinded readers categorized each tumor according to OT-RADS classification. Intraclass correlation (ICC) and Conger κ were used. Diagnostic performance measures including area under the receiver operating curve were reported. Osseous Tumor Reporting and Data System was dichotomized as benign (I-III) and malignant (IV and V) for calculating sensitivity and specificity. RESULTS Interreader agreement for OT-RADS (ICC = 0.78) and binary distinction of benign versus malignant (κ = 0.67) were good to excellent, while agreement for individual tumor feature characteristics were poor to fair (ICC = 0.25-0.36; κ = 0.16-0.39). The sensitivities, specificities, and area under the receiver operating curve of the readers ranged from 0.93-1.0, 0.71-0.86, and 0.92-0.97, respectively. CONCLUSIONS Osseous Tumor Reporting and Data System lexicon is reliable and helps stratify tumors into benign and malignant categories. It can be practically used by radiologists to guide patient management, improve multidisciplinary communications, and potentially impact outcomes.

The Society of Skeletal Radiology (SSR) Practice Guidelines and Technical Standards Committee identified musculoskeletal infection as a White Paper topic, and selected a Committee, tasked with developing a consensus on nomenclature for MRI of musculoskeletal infection outside the spine. The objective of the White Paper was to critically assess the literature and propose standardized terminology for imaging findings of infection on MRI, in order to improve both communication with clinical colleagues and patient care.A definition was proposed for each term; debate followed, and the committee reached consensus. Potential controversies were raised, with formulated recommendations. The committee arrived at consensus definitions for cellulitis, soft tissue abscess, and necrotizing infection, while discouraging the nonspecific term phlegmon. For bone infection, the term osteitis is not useful; the panel recommends using terms that describe the likelihood of osteomyelitis in cases where definitive signal changes are lacking. The work was presented virtually to SSR members, who had the opportunity for review and modification prior to submission for publication.

Magnetic resonance imaging (MRI) is a common choice among various imaging modalities for the evaluation of hip conditions. Conventional MRI with two-dimensional acquisitions requires a significant amount of time and is limited by partial-volume artifacts and suboptimal fluid-to-cartilage contrast. Recent hardware and software advances have resulted in development of novel isotropic three-dimensional (3D) single-acquisition protocols that cover the volume of the entire hip and can be reconstructed in arbitrary planes for submillimeter assessment of bony and labro-cartilaginous structures in their planes of orientation. This technique facilitates superior identification of small labral tears and other hip lesions with better correlations with arthroscopy. In this review, we discuss technical details related to 3D MRI of the hip, its advantages, and its role in commonly encountered painful conditions that can be evaluated with great precision using this technology. The entities described are femoroacetabular impingement with acetabular labral tears, acetabular dysplasia, avascular necrosis, regional tendinopathies and tendon tears, bursitis, and other conditions.

The purpose of this study was to assess the intra- and inter-reader reliability of the 2 Charcot neuroarthropathy classifications (Sanders-Frykberg and Brodsky-Trepman), as well as Eichenholtz staging. We hypothesized that the inter-reader reliability, with respect to these 3 classification systems, would be moderate at best. Digital radiographic images were organized in a digital slide presentation without clinical information. All 5 reviewers underwent a standard training session administered by the principal investigator, reviewing 5 cases of Charcot neuroarthropathy. Images of 55 cases of Charcot neuroarthropathy and 5 normal cases were distributed to each of the 5 physicians electronically, who independently rated all 60 cases according to the 3 classification systems. The 95% confidence interval of the intraclass correlation coefficient estimate for Sanders-Frykberg was 0.9601 to 0.9833 at week 0 and 0.9579 to 0.9814 at week 8, which can be regarded as "excellent" reliability. For Trepman-Brodsky, the 95% confidence interval of the intraclass correlation coefficient estimate was 0.8463 to 0.9327 at week 0 and 0.8129 to 0.9226 at week 8, which can be regarded as "good" to "excellent" reliability. For Eichenholtz, the 95% confidence interval of the intraclass correlation coefficient estimate was 0.6841 to 0.8640 and 0.6931 to 0.8730 at weeks 0 and 8, respectively, which can be regarded as "moderate" to "good" reliability. The classification systems of Charcot neuroarthropathy are an important tool for communication among physicians. Based on the results at our institution, the Sanders-Frykberg classification exhibited the best inter-reader performance. The Trepman-Brodsky classification exhibited good to excellent reliability as well. The intraclass correlation coefficient of the Eichenholtz classification was moderate to good.

Hallux valgus is a complex deformity with a variety of techniques described for correction. A biplanar plating system for triplanar correction system has been developed to address both the translation and rotational component of the hallux valgus deformity and allow an accelerated weightbearing protocol. The purpose of this study was to determine the correction and complications using radiographic parameters and patient reported outcomes. We sought to determine prognostic factors for successful correction, including age, gender, and preoperative deformity. From the medical records, we collected preoperative data. Patient-reported outcomes were obtained using AOFAS Hallux Metatarsophalangeal-Interphalangeal score, FAAM, and SF-12 scores preoperatively and postoperatively. Imaging was reviewed at preoperative and postoperative visits to determine hallux valgus angle, intermetatarsal angle, and tibial sesamoid position. Fifty-seven procedures, in 55 patients, were performed. There were 7 complications and mean follow-up time was 45.7 weeks (+ 28.3 weeks). Age over 62.5 years were associated with an increased risk of complications (p = .018). Males had an increased rate of complications (71%) compared with females. Radiographic parameters were significantly improved from preoperative values at alltime points (p.05). Only the AOFAS Hallux Metatarsophalangeal-Interphalangeal score was statistically significant at 3, 6 and 12 months. We sought to determine the effectiveness of biplanar plating and triplanar correction procedure with early weightbearing. Over a 12 month follow-up period, our results showed significant improvement in deformity and maintained correction. AOFAS Hallux Metatarsophalangeal-Interphalangeal scores significantly improved from the preoperative to the postoperative state. Our results show a nonunion rate of 5.2%, which is comparable to prior studies.

PURPOSE: We assessed the prevalence of low bone mineral density (BMD) in oncologic patients undergoing F-18-FDG-PET/CT. MATERIALS AND METHODS: Retrospective analysis of 100 patients who underwent F-18-FDG-PET/CT at a single center from October 2015 till May 2016. Quantitative computed tomography (QCT) was used to assess BMD at the lumbar spine (BMD(QCT)) and femoral necks (BMD(CTXA)). SUV(max) was used to evaluate metabolic activity of the bone marrow. Risk of osteoporosis-related fractures was calculated with femoral neck BMD(CTXA) and the FRAX® algorithm, which was compared against measurements of CT attenuation of the trabecular bone at L1 (L1(HU)). RESULTS: Osteoporosis/osteopenia were respectively present in 16%/46% of patients ≥ 50 years old. Bone marrow SUV(max) was correlated with BMD at the lumbar spine (ρ=0.36, p

Bone sclerosis is a focal, multifocal, or diffuse increase in the density of the bone matrix on radiographs or computed tomography (CT) imaging. This radiological finding can be caused by a broad spectrum of diseases, such as congenital and developmental disorders, depositional disorders, and metabolic diseases. The differential diagnosis can be effectively narrowed by an astute radiologist in the light of the clinical picture and typical findings on imaging. Some of these lesions are rare and have been described as case reports and series in the literature. This article aims to collate the clinical-radiologic findings of non-infectious and non-neoplastic causes of bone sclerosis with relevant imaging illustrations.

Shoulder osteoarthritis (OA) is a common and debilitating condition and a source of high morbidity and medical expenditures across the world among individuals older than 60 years. Shoulder OA results in the gradual destruction of articular cartilage of the humeral head and glenoid component, causing inflammation, pain, and a restricted range of motion. Most patients are diagnosed with shoulder OA after experiencing shoulder pain and stiffness, and the diagnosis is often made after medical and physical histories are obtained and physical and imaging examinations are performed. Use of various surgical techniques such as total anatomic or reverse shoulder arthroplasty and hemiarthroplasty has increased in recent years, resulting in reduced morbidity and improved functional status of patients. However, the rate of surgical complications such as premature loosening of components is significant, reducing the effectiveness of such procedures. Data in the literature indicate that high-grade fatty infiltration of the rotator cuff muscle before surgery is associated with postoperative glenoid component loosening. High-grade rotator cuff fatty infiltration and atrophy have been found to be associated with more severe Walch classification-based glenoid morphology subtypes, increased joint line medialization, glenoid bone loss, and increased pathologic glenoid version. The authors describe how advanced imaging techniques are used for preoperative evaluation of the shoulder and discuss how to measure glenoid version and bone stock and classify glenoid morphology types on the basis of Walch classification, as these parameters are commonly used in surgical planning. Methods involving the use of Friedman and paleoglenoid lines for respective measurements are illustrated by using three-dimensional CT and MRI case examples. ©RSNA, 2020.

Objective To evaluate the inter-rater and intermethod correlation (reliability between MRI and arthroscopy) of knee for findings of meniscus tears using International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) classification on both 1.5 and 3.0 T images. Methods 81 knees were evaluated in 69 patients aged 30.0±12.6 years (mean±SD). Consecutive arthroscopy-proven meniscal tears were evaluated by two board-certified radiologists on MRI and two sports surgeons on arthroscopies. The surgically validated ISAKOS classification of meniscal tears was used to describe medial meniscus (MM) and lateral meniscus (LM) tears on MRI and re-evaluation of images from completed arthroscopies. Prevalence-adjusted bias-adjusted kappa (PABAK), t-tests and intraclass correlation coefficient (ICC) were calculated. Results For LM on 1.5 T, the agreements for location, depth, tear length and pattern were good to excellent in all categories except fair for tissue quality (PABAK=0.35–0.41) and zone 2 (PABAK=0.35) identification. For MM, the agreements were good to excellent in all except moderate for tissue quality (PABAK=0.6) and zone 1 and 3 (PABAK=0.40–0.47), and fair for zone 2 identification (PABAK=0.27). Similar results were seen on 3 T with improved LM zonal identification (PABAK=0.52–0.90) and better correlation of tear lengths, which were different on 1.5 T vs 3.0 T (p=0.01–0.03). For 1.5 T cases, both MM and LM tear lengths were larger on MRI versus arthroscopy (MM, p=0.004; LM, p=0.095). For 3 T, the MM tear lengths were larger on MRI versus arthroscopy (p=0.001). Conclusion ISAKOS classification of meniscal tears on both 1.5 and 3.0 T MRI provides satisfactory inter-rater and intermethod reliability for use in clinical practice. Level of evidence: IV.

Purpose Glenoid bone stock and morphology and rotator cuff muscle quality and tendon integrity affect the outcome of total shoulder arthroplasty. We hypothesized that glenoid bone loss correlates with rotator cuff muscle fatty infiltration (FI), tendinopathy, and atrophy. Design Forty-three 3-D CT scans and MRIs of 43 patients (mean age 62 years; SD 13 years; range 22–77 years) referred for primary shoulder pain were evaluated. Measurements of glenoid bone stock, version, and posterior humeral subluxation index (HSI) were assessed on an axial CT image reconstructed in the true scapular plane. Measurements utilized the Friedman line to approximate the pre-pathologic surface. Glenoid morphology was assigned by modified Walch classification. Rotator cuff FI, atrophy, and tendon integrity were assessed on corresponding MRIs. Results There was a very strong negative correlation between increasing glenoid version and HSI (r = − 0.908; p

Introduction: MR neurography (MRN) of the brachial plexus has emerged in recent years as a safe and accurate modality for the identification of brachial plexopathies in pediatric and adult populations. While clinical differentiation of brachial plexopathy from cervical spine-related radiculopathy or nerve injury has long relied upon nonspecific physical exam and electrodiagnostic testing modalities, MRN now permits detailed interrogation of peripheral nerve anatomy and pathology, as well as assessment of surrounding soft tissues and musculature, thereby facilitating accurate diagnosis. The reader will learn about the current state of brachial plexus MRN, including recent advances and future directions, and gain knowledge about the adult and pediatric brachial plexopathies that can be characterized using these techniques.Areas Covered: The review details recent developments in brachial plexus MRN, including increasing availability of 3.0-T MR scanners at both private and academic diagnostic imaging centers, as well as the advent of multiple new vascular and fat signal suppression techniques. A literature search of PubMed and SCOPUS was used as the principal source of information gathered for this review.Expert Opinion: Refinement of fat-suppression, 3D techniques and diffusion MR imaging modalities has improved the accuracy of MRN, rendering it as a useful adjunct to clinical findings during the evaluation of suspected brachial plexus lesions.

Androgen deprivation therapy (ADT) is a cornerstone of advanced prostate cancer (PCa) therapy. Its use is associated with a loss of bone mineral density (BMD) and a greater risk of falls and osteoporotic fractures. In this prospective cohort study, we examined the impact of ADT on muscle and bone strength in men initiating ADT for PCa. Participants were evaluated at three time points: immediately before (week 0), and 6 and 24 weeks after ADT initiation. Study measures included fasting blood levels (for markers of muscle and bone metabolic activity), MRI and QCT imaging (for muscle fat content, and bone density and architecture), and validated clinical tests of muscle strength and gait. Sixteen men completed all study visits. At baseline and throughout the study, participants exercised a median of four times/week, but still experienced weight gain (+2.0 kg at week 24 versus week 0, p = 0.004). Biochemically, all men sustained dramatic early and persistent reductions in sex hormones post‐ADT, along with a progressive and significant increase in serum C‐telopeptide of type I collagen (CTX, +84% at week 24 versus week 0). There was a trend for rise in serum sclerostin (p = 0.09) and interleukin 6 (IL‐6) (p = 0.08), but no significant change in serum myostatin (p = 0.99). Volumetric BMD by QCT declined significantly at the femoral neck (−3.7% at week 24 versus week 0), particularly at the trabecular compartment. On MRI, there were no significant changes in thigh muscle fat fraction. On physical testing, men developed weaker grip strength, but experienced no worsening in lower extremity and lumbar spine muscle strength, or on functional tests of gait. In conclusion, in physically active men, ADT for 24 weeks results in a significant increase in bone resorption and reduction in BMD, but nonsignificant changes in thigh muscle quality (on imaging) or strength and gait (on functional testing). © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Musculoskeletal (MSK) radiologists are predominantly consultants in the service departments of health care. Unlike the manufacturing industry, quality controls are difficult to institute in a service industry and more variability is expected. Structured reporting is a unique way to institute quality standards, and by using the checklist approach with uniform terminology, it can lead to more homogeneity and consistency of reporting, concise lexicon use within and across practices, minimization of errors, enhancement of divisional and departmental branding, improvement of interdisciplinary communications, and future data mining. We share our experience from more than a decade of structured reporting in the domain of MSK radiology, our practice standards, and how reporting has evolved in our MSK practice. Further discussions include future directions aided by machine learning approaches with augmented reality and the possibility of virtual fellowship and training using consistent lexicons and structured reporting.

BACKGROUND: Pyruvate dehydrogenase (PDH) and lactate dehydrogenase are essential for adenosine triphosphate production in skeletal muscle. At the onset of exercise, oxidation of glucose and glycogen is quickly enabled by dephosphorylation of PDH. However, direct measurement of PDH flux in exercising human muscle is daunting, and the net effect of covalent modification and other control mechanisms on PDH flux has not been assessed. PURPOSE: To demonstrate the feasibility of assessing PDH activation and changes in pyruvate metabolism in human skeletal muscle after the onset of exercise using carbon 13 ((13)C) MRI with hyperpolarized (HP) [1-(13)C]-pyruvate. MATERIALS AND METHODS: For this prospective study, sedentary adults in good general health (mean age, 42 years ± 18 [standard deviation]; six men) were recruited from August 2019 to September 2020. Subgroups of the participants were injected with HP [1-(13)C]-pyruvate at resting, during plantar flexion exercise, or 5 minutes after exercise during recovery. In parallel, hydrogen 1 arterial spin labeling MRI was performed to estimate muscle tissue perfusion. An unpaired t test was used for comparing (13)C data among the states. RESULTS: At rest, HP [1-(13)C]-lactate and [1-(13)C]-alanine were detected in calf muscle, but [(13)C]-bicarbonate was negligible. During moderate flexion-extension exercise, total HP (13)C signals (tC) increased 2.8-fold because of increased muscle perfusion (P = .005), and HP [1-(13)C]-lactate–to-tC ratio increased 1.7-fold (P = .04). HP [(13)C]-bicarbonate–to-tC ratio increased 8.4-fold (P = .002) and returned to the resting level 5 minutes after exercise, whereas the lactate-to-tC ratio continued to increase to 2.3-fold as compared with resting (P = .008). CONCLUSION: Lactate and bicarbonate production from hyperpolarized (HP) [1–carbon 13 {(13)C}]-pyruvate in skeletal muscle rapidly reflected the onset and the termination of exercise. These results demonstrate the feasibility of imaging skeletal muscle metabolism using HP [1-(13)C]-pyruvate MRI and the sensitivity of in vivo pyruvate metabolism to exercise states. © RSNA, 2021 Online supplemental material is available for this article.

High-resolution ultrasonography (US) and magnetic resonance neurography (MRN) have followed parallel paths for peripheral nerve imaging with little comparison of the two modalities. They seem equally effective to study a variety of neuropathies affecting large and small nerves in the wrist and hand. This article outlines the technical considerations of US and MRN and discusses normal and abnormal imaging appearances of hand and wrist nerves from etiologies such as entrapment, injury, tumor, and proximal and diffuse neuropathy, with specific case illustrations.

Aims Some patients presenting with hip pain and instability and underlying acetabular dysplasia (AD) do not experience resolution of symptoms after surgical management. Hip-spine syndrome is a possible underlying cause. We hypothesized that there is a higher frequency of radiological spine anomalies in patients with AD. We also assessed the relationship between radiological severity of AD and frequency of spine anomalies. Methods In a retrospective analysis of registry data, 122 hips in 122 patients who presented with hip pain and and a final diagnosis of AD were studied. Two observers analyzed hip and spine variables using standard radiographs to assess AD. The frequency of lumbosacral transitional vertebra (LSTV), along with associated Castellvi grade, pars interarticularis defect, and spinal morphological measurements were recorded and correlated with radiological severity of AD. Results Out of 122 patients, 110 (90.2%) were female and 12 (9.8%) were male. We analyzed the radiographs of 122 hips (59 (48.4%) symptomatic left hips, and 63 (51.6%) symptomatic right hips). Average age at time of presentation was 34.2 years (SD 11.2). Frequency of LSTV was high (39% to 43%), compared to historic records from the general population, with Castellvi type 3b being the most common (60% to 63%). Patients with AD have increased L4 and L5 interpedicular distance compared to published values. Frequency of pars interarticularis defect was 4%. Intraclass correlation coefficient for hip and spine variables assessed ranged from good (0.60 to 0.75) to excellent (0.75 to 1.00). Severity of AD did not demonstrate significant correlation with frequency of radiological spine anomalies. Conclusion Patients with AD have increased frequency of spinal anomalies seen on standard hip radiographs. However, there exists no correlation between radiological severity of AD and frequency of spine anomalies. In managing AD patients, clinicians should also assess spinal anomalies that are easily found on standard hip radiographs. Cite this article: Bone Joint J 2021;103-B(8):1351–1357.

The relationship among the severity of the imaging features of femoroacetabular impingement syndrome (FAIS), patient symptoms, and function has not been elucidated. Understanding this relationship helps to improve the prognostic value of imaging. The goal of this study was to examine the correlation of clinical findings, patient pain, and function with severity, as measured with radiographic and 3-dimensional magnetic resonance imaging (3D-MRI). Data collected prospectively through a longitudinally maintained hip database were reviewed, and 37 hips from 31 patients were included. All patients were examined by an experienced orthopedic surgeon, and preoperative radiographs and 3D-MRI were obtained. Preoperatively, the patients completed validated patient-reported outcome measures (PROMs). Mean±SD alpha angles were 69.4°±10.3°, 70.0°±10.3°, 70.6°±8.4°, and 74.8°±9.2° at 12 o'clock, 1 o'clock, 2 o'clock, and 3 o'clock, respectively. Mean lateral center edge angle was 30.1°±5.3°. The authors did not observe a statistically significant correlation between PROMs and the features measured by radiographs and 3D-MRI ( P >.05). In this subset of prospectively imaged patients with FAIS, the authors did not find a correlation between the severity of symptoms measured by PROMs and features on radiographs and 3D-MRI. The severity of dysfunction is multifactorial, and anatomic severity, as measured radiographically and with 3D-MRI, may not correlate with symptoms. Further investigation is necessary to address the sources of patient pain. [ Orthopedics . 2021;44(4):e577–e582.]

Background Chronic groin neuralgia is a life-debilitating condition that plagues patients worldwide. While groin neuralgia is usually traced to iatrogenic causes (inguinal hernia repairs, vasectomy, and hysterectomy), there is a unique subset of patients that present with noniatrogenic groin neuralgia. The diagnosis and treatment of these patients present a particular challenge. Methods A total of 30 patients (current mean age, 46.5 [range: 19–72] years) who presented with noniatrogenic groin neuralgia and received neurectomies on the iliohypogastric, ilioinguinal, and genitofemoral nerves between 2008 and 2017 were identified. A retrospective review of preoperative and immediate postoperative pain scores was compared with prospectively collected current pain on a Likert's scale (0–10). Additionally, patients were asked to complete a Short Form (SF)-20 and identify current pain medications. A two-sided Wilcoxon–Mann–Whitney test was used to analyze the data. Results Of the 30 patients identified, 16 could participate (mean follow-up = 61 months). The average pain reduction for the entire group was 62.7%. When using an established 30% reduction pain as a marker for clinical significance, 12 successful and 4 unsuccessful patients had an average reduction of 81.1 and 7.68%, respectively (success rate of 75%). Patients with successful group showed a statistically significant increased social functioning (p = 0.012) and near-significant increase in mental health (p = 0.063). Improvements, albeit nonsignificant, in mean scaled scores for every other SF-20 quality of life (QoL) category were observed when comparing both groups. Conclusion Neurectomy is a potentially beneficial surgery that can assuage pain and improve quality of life for patients with noniatrogenic groin neuralgia.

To quantify and compare signal intensity (SI) changes on T1-weighted (W) and T2W Dixon imaging in yellow marrow, red marrow, and bone marrow lesions. A total of 141 patients (77 controls, 64 lesions—33 benign, 31 malignant) between January 2016 and December 2017 were retrospectively identified. For the control group, fixed 2-cm2 region of interests (ROI) were drawn at L5, bilateral ilium and femurs on in-phase and opposed-phase T1W and T2W Dixon images. For the lesion group, ROIs of best fit were drawn around each lesion on in-phase and opposed-phase T2W Dixon images. SI changes between in-phase and opposed phase maps for each group were compared. Inter-reader analysis was performed. Yellow marrow exhibited smaller SI changes as compared to red marrow on both T1W and T2W Dixon imaging at all locations (p

To quantify and compare changes in bone mineral density (BMD) via CT analysis in patients with and without spontaneous femoral fractures.Consecutive series of patients with CT imaging for spontaneous femoral fractures were compared to the age and gender matched controls. Bone density fixed region of interest measurements were obtained at the site of the fracture, proximally at the femoral head, and distally at the lesser trochanter in fracture patients and controls. Inter- and intrapatient comparisons were performed, including Chi-square and t-test analyses.24 spontaneous fractures and 25 controls were analyzed with no significant differences in mean age, gender, or body mass index. There were differences in the bone density between the fracture and contralateral non-fracture sides at (p = 0.0001) and distal (p 0.0001) to the fracture. Proximal and distal bone density differences existed between case fracture and control non-fracture sites (p 0.0001, p = 0.0001), and between the case non-fracture and control non-fracture sites (p 0.0001, p 0.0001). The reliability for measurements was good to excellent proximally (ICC = 0.63-0.87), moderate to excellent at the fracture site (ICC = 0.43-0.78), and fair to good distal (ICC = 0.24-0.68) to the fracture site.Patients with spontaneous femoral fractures exhibit lower bone density than the asymptomatic controls. Bone insufficiency is best demonstrated proximal or distal to, rather than at the fracture site.

Aim: To evaluate the utility of percutaneous CT guided bone biopsy (PCBB) for suspected osteomyelitis (OM) and its eventual impact on patient management and recovery. Material and methods: Patients who received a PCBB for suspected osteomyelitis from years 2012-2018. Patient demographics, lesion location, ulcer grade, signs of toxemia, serology, wound and blood cultures, bone biopsy and cross-sectional imaging results were recorded. Diagnostic yield of the bone biopsy and its role in influencing the final treatment plan and patient recovery were evaluated. Chi-square test was used. P-value less than 0.05 was considered statistically significant. Results: 115 patients with mean age 50.86 ± 14.49 years were included. The common locations were sacrum/ischium (49/115, 43%) and spine (35/115, 30%). Clinically, 40/115 (35%) had toxemia and 67/115 (58%) had ulcers. Per serology, 17/111 (15%), 95/106 (90%), and 86/98 (88%) had an elevated WBC, CRP, and sedimentation rate, respectively. 22/91 (24%) had a positive blood culture and all 23/23 had a positive wound culture. On imaging, definitive and possible OM were reported in 84.1% and 14.2%, respectively, with 1.8% as no OM. Only 24/115 (21%) had a positive bone biopsy culture and only 10/24 (42%) total positive bone cultures impacted the treatment plan. There was no significant effect of antibiotics on the diagnostic yield of culture (p = 0.08). No statistical significance was found when comparing treatment change based on bone culture results versus all other factors combined (p = 0.33), or when comparing clinical improvement with and without positive bone cultures (p = 0.12). Conclusion: Despite positive cross-sectional imaging findings of OM, bone biopsy yield of positive culture is low, and it leads to a small impact in changing the treatment plan or altering the course of patient recovery.

Pediatric musculoskeletal tumors comprise approximately 10% of childhood neoplasms, and MR imaging has been used as the imaging evaluation standard for these tumors. The role of MR imaging in these cases includes identification of tumor origin, tissue characterization, and definition of tumor extent and relationship to adjacent structures as well as therapeutic response in posttreatment surveillance. Technical advances have enabled quantitative evaluation of biochemical changes in tumors. This article reviews recent updates to MR imaging of pediatric musculoskeletal tumors, focusing on advanced MR imaging techniques and providing information on the relevant physics of these techniques, clinical applications, and pitfalls.

Aim Radiographs (X-rays) are used for the preoperative assessment of hallux valgus (HV). Our purpose was to determine how well quantitative measurements of HV on radiographs and MRI correlate with the qualitative soft tissue and internal derangement findings on MRI. Materials and methods After IRB approval, 56 consecutive patients with MRI and radiographs of the foot were retrospectively reviewed. Two trained readers independently evaluated radiographs, measuring hallux valgus angle (HVA) and intermetatarsal angle (IMA). Two separate readers assessed qualitative MRI data by evaluating 21 different soft tissue and bony features. Statistical analysis included inter-reader reliability (IRR) and correlation of quantitative and qualitative findings. Results Excellent IRR (ICC = 0.89–0.96) was observed for radiograph and MRI measurements of the hallux valgus severity. For qualitative assessments on MRI, IRR was good to excellent for all features (ICC = 0.63–0.9). No significant difference was found for HVA or IMA between normal and abnormal qualitative MRI features. No statistically significant correlation between the severity of hallux valgus and injury to hallux joints and supporting structures was found. Conclusion Hallux valgus measurements are reliable on x-rays and MRI and qualitative findings of 1st MTP joint show good to excellent inter-reader agreement on MRI. No statistically significant correlations exist between the severity of hallux valgus and qualitative MRI findings.

Background Successful healing of the subscapularis during anatomic total shoulder arthroplasty surgery is critical to optimize functional outcomes and avoid complications. The purpose of this study was to examine the upper and lower subscapularis nerve insertion in relation to the musculotendinous junction to estimate the risk of nerve injury. Our hypothesis was that arm position changes the risks to these nerves when exposing the anterior glenoid. Methods Twenty cadaveric shoulders were dissected, and the subscapular nerves were identified from the posterior cord of the brachial plexus to the muscle insertion. The nerve length from the origin to the muscle insertion and the distance to the myotendinous junction were measured in various shoulder positions including neutral, external, and internal rotation. Results The mean length of the upper subscapular nerve was 51.4 ± 12.8 mm; that of the lower subscapular nerve was 50.5 ± 14 mm. The mean distance from the insertion of the upper subscapular nerve to the myotendinous junction 53.0 ± 14.7 mm with external rotation, 38.5 ± 9.7 mm with neutral rotation, and 30.0 ± 9.2 mm with internal rotation. The mean distance from the lower subscapular nerve to the myotendinous junction was 44.5 ± 13.8 mm with external rotation, 31.9 ± 9.3 mm with neutral rotation, and 25.4 ± 8.8 mm with internal rotation. The internally rotated position placed these nerves closest to the glenohumeral joint. Conclusion The upper and lower subscapular nerves insert in the muscle belly close to the myotendinous junction, putting them at risk of iatrogenic injury. Care must be taken to avoid damage with retractor placement in the anterior glenoid neck as these nerves are at risk of compression or torsional injury.

Determine correlations of 3DCT cam-type femoroacetabular impingement (FAI) measurements with surgical findings of labral tear and cartilage loss. Digital search of symptomatic cam-type FAI from July 2013 to August 2016 yielded 43 patients. Two readers calculated volumes of femoral head, bump, and alpha angles on 3DCT images. Correlations between CT and surgical findings, inter-, and intra-reader reliabilities were assessed using Spearman rank correlation and intraclass correlation coefficients (ICC). Thirteen men and 14 women aged 37 ± 10 (mean ± SD) years were included. Most common clinical finding was positive flexion–adduction–internal rotation (70.4%). Twenty-seven labral tears and 20 cartilage defects were surgically detected. Significant correlations existed between femoral bump, head volumes, and extent of the labral tear (p = 0.008 and 0.003). No significant correlations were found between the alpha angles at 12 to 3 o’clock and the extent of labral tear (p = 0.2, 0.8, 0.9, and 0.09) or any measurement with the cartilage loss (p values for alpha 12 to 3, bump, and head volumes = 0.7, 0.3, 0.9, 0.9, 0.07, and 0.2). Inter- and intra-reader reliabilities were excellent to moderate for femoral head and bump volumes (ICC = 0.85, 0.52, and 0.8, 0.5) and moderate to poor for alpha angles (ICC = 0.48, 0.40, 0.05, 0.25 and 0.3, 0.24, 0.29, 0.49). Three dimensional volumetric measurements of cam-type FAI significantly correlate with the extent of intraoperative labral tears. Superior inter- and intra-reader reliability to that of alpha angles renders it a more clinically relevant measurement for quantifying cam morphology. • The 3DCT bump volume and femoral head volume showed significant correlations with the extent of labral tear (p values = 0.008 and 0.003). • No significant correlations were seen between alpha angles and the extent of labral tear (p values > 0.05). • Inter- and intra-reader reliability was excellent to moderate (ICC = 0.85 and 0.52, 0.8, and 0.5) for femoral head and bump volumes while inter- and intra-reader reliability was fair to poor (ICC = 0.48, 0.40, 0.05, 0.25 and 0.3, 0.24, 0.29, 0.49) for alpha angles.

BackgroundThe purpose of this study was to define the relationship of the axillary and radial nerves, particularly how these are affected with changing arm position.MethodsTwenty cadaveric shoulders were dissected, identifying the axillary and radial nerves. Distances between the latissimus dorsi tendon and these nerves were recorded in different shoulder positions. Positions included adduction/neutral rotation, abduction/neutral rotation for the axillary nerve, adduction/internal rotation, adduction/neutral rotation, adduction/external rotation, and abduction/external rotation for the radial nerve.ResultsWidth of the latissimus tendon at its humeral insertion was 29.3 ± 5.7 mm. Mean distance from the latissimus insertion to the axillary nerve in adduction/neutral rotation was 24.2 ± 7.1 mm, the distance increased to 41.1 ± 9.8 mm in abduction/neutral rotation. Mean distance from the latissimus insertion to the radial nerve was 15.3 ± 5.5 mm with adduction/internal rotation, 25.8 ± 6.9 mm in adduction/neutral rotation, and 39.5 ± 6.8 mm in adduction/external rotation. Mean distance increased with abduction/external rotated 51.1 ± 7.4 mm.ConclusionsKnowing the axillary and radial nerve locations relative to the latissimus dorsi tendon decreases the risk of iatrogenic nerve injury. Understanding the dynamic nature of these nerves related to different shoulder positions is critical to avoid complications.

Sickle cell anemia is an inherited disorder with many systemic complications. Peripheral neuropathy related to this disorder has been sparsely reported. We report an interesting case of upper limb peripheral neuropathy from sickle cell disease with emphasis on MR neurography appearances and electrophysiology correlation.

Purpose The accuracy of magnetic resonance neurography (MRN) for quantitative assessment of nerve injury gap is unknown. We tested the hypothesis that presurgical MRN predicts the final surgical gap size after neuroma resection at the time of surgery. Materials and Methods This was a retrospective, single-blinded, nonrandomized cohort study on 43 patients with Sunderland Class IV and V injuries of the inferior alveolar (IAN) or the lingual nerve (LN). The MRN maxillofacial protocol was performed on a 3T scanner and was read by 2 musculoskeletal radiologists to determine the maximum size of neuroma and the abnormal nerve segment. Two independent variables were recorded during surgery: 1) the length of neuroma from histologic specimens since only 9 of the 43 neuroma size measurements were accurately measureable at the time of surgery; and 2) the length of nerve gap size after the neuroma was removed and normal fascicles were identified. Results There were 7 IAN and 36 LN cases analyzed. The mean time in months from injury to MRN was 6.97 ± 9.18 and MRN to surgery was 1.21 ± 1.4. The mean length of the neuroma at surgery was 7.22 ± 2.78 mm and mean nerve gap size was 12.02 ± 4.41 mm. Intraclass coefficient (ICC) agreement was fair for abnormal nerve thickness and neuroma length (ICC = 0.28, 0.39) while it was moderate for neuroma thickness and abnormal nerve length (0.50, 0.59). There was no significant correlation between MRN based measurements and surgical gap size for both readers (P > .05). Conclusions Abnormal nerve and neuromas of the peripheral trigeminal nerve as identified on MRN imaging demonstrates no correlation of the assessed MRN findings with the final surgical gap after neuroma removal.

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms composed of spindled to epithelioid cells that co-express both melanocytic and myogenic markers. Recently, in 2018, a distinctive variant of PEComa has been described that arises in association with tuberous sclerosis complex (TSC) and resembles a fibroma by conventional morphology (called fibroma-like PEComa). Herein, we describe a case of a fibroma-like PEComa in a 4-year-old male child with a known diagnosis of tuberous sclerosis who presented with a firm mass along the anteromedial aspect of the right knee. The mass was excised, and microscopic examination showed bland spindled to stellate cells embedded in a dense collagenous stroma, morphologically resembling a fibroma. Immunohistochemistry analysis showed positivity for desmin (a myogenic marker) and HMB45 (a melanocytic marker), a hallmark for PEComas. To our knowledge, only six cases of fibroma-like PEComa have been described in the literature so far and this is the first report of such a tumor in the medial retinaculum of the knee joint with illustrations of conventional and diffusion imaging features. This case highlights the unique association of fibroma-like PEComa lesions with TSC. This should be considered a differential diagnosis for T2 hypointense masses in tuberous sclerosis patients. In addition, a diagnosis of fibroma-like PEComa should prompt further evaluation for associated TSC.

Bone tumors and tumor-like lesions (pseudotumors) are not uncommonly encountered as asymptomatic findings on imaging, or as symptomatic lesions clinically. Radiographic imaging is the first diagnostic tool for their management strategy, since the symptoms are commonly non-specific, such as pain, swelling, and redness. Image findings must be analyzed with attention to the specific features such as lesion location, margination, zone of transition, mineralization, size and multifocality, soft tissue component and/or loco-regional extent. Cross-sectional imaging including CT and MRI serve as complementary methods, providing additional information with respect to the lesion characterization, mineralization, extent and involvement of the adjoining soft tissues. Clinical and/or key imaging features aid in limiting the differential diagnostic possibilities and serve as a guide in determining the benignity or malignancy of the tumor as well as to exclude pseudotumors. This article reviews the key imaging features of foot and ankle lesions. Benign bone lesions include simple and aneurysmal bone cysts, lipoma, hemangioma, chondroblastoma, enchondroma, osteoid osteoma, osteoblastoma, and giant cell tumor. Locally aggressive intermediate category lesion includes hemangioendothelioma. Malignant lesions include osteosarcoma, Ewing's sarcoma, chondrosarcoma. Pseudotumors such as fibrous dysplasia, hemophilic pseudotumor, gout and Madura foot are also discussed with illustrative case examples.

Objectives Synovial sarcomas commonly involve extremities. The purpose of this study was to systematically assess and describe the appearance of pathologically proven synovial sarcomas on conventional MR sequences, diffusion weighted imaging and dynamic contrast enhanced imaging. Methods In this cross-sectional retrospective study, fifteen pre-operative MRIs were analyzed separately by two musculoskeletal radiologists and a fellow. MRI features of synovial sarcomas were evaluated in a systematic fashion on conventional and advanced MR sequences. Results The tumors demonstrated heterogeneous appearance on conventional MR sequences. Peritumoral edema was absent in four of 15 (27%) lesions including grade 2 and grade 3 tumors. Average minimum ADC was 0.8 × 10–3 mm2/s and average mean ADC was 1.2 × 10–3 mm2/s. There was avid early arterial phase enhancement on contrast imaging. Average relative enhancement of the tumors was 5.7 times compared to the adjacent skeletal muscle. Conclusion Synovial sarcomas demonstrate avid early arterial phase post-contrast enhancement on contrast images, low ADC values, and heterogeneous appearance on conventional MRI sequences. Peritumoral edema may be absent in such tumors despite being high grade tumors.

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: The majority of hallux valgus corrections are performed via a uniplanar metatarsal osteotomy approach in which the metatarsal is cut and shifted over in the transverse plane. This approach has demonstrated high long-term recurrence rates. Recent research demonstrates that 87% of hallux valgus deformities are three-dimensional with abnormal frontal-plane rotation of the metatarsal, which cannot be fully addressed with a uniplanar metatarsal osteotomy. While correction at the 1st tarsometatarsal (TMT) joint may provide the optimal surgical approach for 3D anatomic restoration at the apex of the deformity, 1st TMT fusion has historically involved an extended period of non-weightbearing. This study evaluates the clinical, radiographic, and patient-reported outcomes in patients undergoing instrumented triplanar 1st TMT arthrodesis (TTA) with a biplanar plating system and protected near-immediate weightbearing. Methods: This is a prospective multicenter study that will continue for 60 months post-operatively. Patients between 14-58 years old with symptomatic hallux valgus (intermetatarsal and hallux valgus angles between 10.0-22.0° and 16.0-40.0°, respectively) and no prior hallux valgus surgery on the operative foot are eligible for this study. Patients are treated with an TTA procedure using a biplanar plating system with protected near-immediate weightbearing. Outcomes (radiographic, range of motion (ROM), pain measured by visual analog scale (VAS), Manchester-Oxford Foot Questionnaire (MOxFQ), return to weightbearing and activities) are evaluated post-operatively. Two independent musculoskeletal radiologists reviewed radiographic data. These interim results are limited to patients completing at least 6 weeks of follow-up. Results: At time of data cut-off, 74 patients had undergone TTA with at least 6 weeks follow-up. The majority of patients were women (95%) with mean age 41.7 years. The mean (95% confidence interval) time to protected weightbearing in CAM boot was 8.0 (6.4, 9.7) days, return to work was 19.0 (13.6, 24.4) days, and return to full work was 31.5 (22.7, 40.2) days. There was a significant change in radiographic measures pre vs. post procedure and changes were maintained over time (Table). VAS pain score decreased 4 and 6 months post-procedure by 3.9 (3.2, 4.6) and 4.2 (3.5, 5.0), respectively. The mean MOxFQ Index Score pre-procedure was 53.3 (49.5, 57.1) and at month 6 had decreased to 18.6 (12.9, 24.2). Conclusion: These interim findings support that TTA with biplanar plating is successful in correcting the 3D hallux valgus deformity with early return to weightbearing and demonstrated favorable clinical and patient-reported outcomes. Patients were able to return to full, unrestricted work and activities within just a few months and had meaningful pain reduction after surgery. Patients will continue to be followed for up to 60 months. Clinical/radiographic healing at 12 months and recurrence rates at 24 months, as well as complications and patient satisfaction, will be evaluated. [Table: see text]

Osteoarthritis is one of the most common causes of ambulatory disability. Developmental dysplasia of the hip (DDH) and femoroacetabular impingement (FAI) may lead to premature osteoarthritis in a young adult population. Current clinical assessments of DDH and FAI include clinical history, static radiological metrics, and physical examinations. Methods involving dynamic radiography such as fluoroscopy are costly and time-consuming for both patient and physician. Therefore, our aim was to simulate dynamic gait on 3D static radiological images of hips to generate "virtual interference" points between the femur and acetabulum with three methods of center-of-rotation (COR): static spherical, dynamic spherical, and dynamic ellipsoidal. We simulated the gait kinematics on pre-segmented CT images for three groups: DDH (N=10), FAI (N=10), and asymptomatic normal (N=11). The femoral head was divided into four medial quadrants to compare the ratios of virtual interference within the regions along the gait cycle and as a temporal mean. We hypothesized that discriminating characteristics would exist between the two pathologies and for the dynamic COR methods to have more discriminating characteristics than the static COR method. For each COR method, we found the temporal mean of virtual interference to be significantly different in almost every region between the hip conditions. The significance was most distinct when using the static spherical method of COR. These results are promising to individual clinical assessments of hip pathologies using static radiographs and ultimately work towards preventing premature hip disease.

To analyze the trends in international medical graduates (IMGs) matching into diagnostic radiology residency programs in the United States (US).The National Resident Match Program data was accessed for years 2005-2020 and diagnostic radiology residency-specific data was extracted for US MD, osteopathic (DO), and IMG applicants. IMGs were categorized into US-citizen IMGs and non-US citizen IMGs per the National Residency Match Program. Variables collected for each year included the number of positions, number of applicants in each group, positions filled/unfilled, and fill rate of each group. Additional data for some years included USMLE Step 1 score, United States Medical Licensing Examination (USMLE) Step 2 clinical knowledge (CK) score, number of research experiences, number of abstracts/publications, and additional degrees obtained. Trends were analyzed using simple linear regression model and p value0.05 was considered significant.The number of diagnostic radiology residency programs increased from 203 (2006) to 212 (2020). The total number of diagnostic radiology residency positions increased from 1011 (2006) to 1113 (2020), with the peak of 1145 in 2014. The overall "match rate," that is, proportion of positions filled to positions available, increased from 96.4% (2006) to 97.3% (2020), with a brief decline to 86.7% in 2015. Among the filled positions, the proportion filled by US medical school graduates significantly declined from 89.7% (2006) to 69.2% (2020) (p0.001), and the proportion of positions filled by osteopathic seniors and graduates significantly increased from 2.2% (2006) to 15.1% (2020; p0.001). The proportion of US IMGs increased from 3.2% (2006) to 5.4% (2020), while the proportion of non-US IMGs increased from 4.4% (2006) to 9.4% (2020), with overall IMG match rate increased significantly from 7.6% to 14.9% (p = 0.009). The mean Step 1 scores of US IMGs and non-US IMGs were 238 and 237.3, and the mean Step 2 CK scores were 241.67 and 241, respectively. Cumulatively over the study period, a total of 736 US IMGs and 1051 non-US IMGs have matched into diagnostic radiology residency.There is an increasing proportion of IMGs, especially the non-US citizen IMGs, matching into US radiology residency programs in the last decade. Diagnostic radiology remains a competitive specialty evidenced by average USMLE scores higher than national average and research experiences of matched candidates.

Introduction To conduct a morphometric analysis of intact and torn menisci using isotropic meniscus plane three-dimensional (3D) reconstructions on 3-Tesla MRI and compare 2D versus 3D MRI for meniscus tear characterization. Materials and methods One hundred thirty three normal menisci from 92 patients (39 male, 53 female), and 38 arthroscopy-proven torn menisci from 36 patients (23 male, 13 female) were evaluated using 3D isotropic multi-planar MRI reconstructions and 2D MRI. Two observers measured the tibial plateau height and area, meniscal height, axial plane cross-sectional areas, and extrusion of intact menisci. Two observers also measured the meniscal tear length, tear area, and residual area of pathological menisci on 2D and 3D MRI. Intraclass correlation coefficients (ICC) were obtained. Institutional Review Board approval was obtained, and the informed consent was waived. Results Medial meniscus (MM) and lateral meniscus (LM) areas were 503.6 ± 85.1 mm2 and 396.6 ± 72.0 mm2 for Observer 1, and 515.8 ± 82.1 mm2 and 408.0 ± 68.3 mm2 for Observer 2 (ICC:0.86, 0.87). In torn menisci, average tear length, area, and residual area were 36.3 ± 13.6 mm, 182.6 ± 139.3 mm2 , and 235.4 ± 140.3 mm2 , respectively for Observer 1, and 38.9 ± 14.7 mm, 181.2 ± 135.6 mm2 , 238.2 ± 140.5 mm2 for Observer 2. In the MM and LM, bucket-handle and complex tears were largest in areas, respectively. ICCs were excellent (0.91-1.0) on 3D MRI and moderate-good (0.57-0.81) on 2D MRI. Conclusion Meniscus morphometry on 3D MRI shows moderate to excellent inter-observer reliability and meniscus tear extent is more reliably defined on 3D MRI than 2D MRI. Residual meniscus-area calculation can be performed on 3D MRI.