Background: Cytology is widely utilized in the initial evaluation of fluid accumulation in the body cavities. The aim of this study was to determine the accuracy of cytology in distinguishing between benign and malignant (MAL) effusions. Methods:A comprehensive and systematic review of the literature was conducted to evaluate the accuracy of serous effusion cytology (SEC) against tissue biopsy/resection histology, imaging, or clinical follow-up as the reference test. Risk of publication bias and level of heterogeneity in the included studies was assessed. Meta-regression was performed to assess the effect of various variables on the accuracy of SEC. Results: Eighty studies met the inclusion criteria for meta-analysis comprising of 34 941 samples; of which 52 (0.2%), 22 202 (72.7%), 194 (0.6%), 711 (2.3%), and 6507 (21.3%) could be reclassified as nondiagnostic (ND), negative for malignancy (NFM), atypical (atypia of uncertain significance-AUS), suspicious for malignancy (SFM), and malignant (MAL), respectively. On follow-up, the mean risk of malignancy for ND, NFM, AUS, SFM, MAL was 17.4%, 20.7%, 65.9%, 81.8%, and 98.9%, respectively. A total of 73 studies were included in estimating the diagnostic accuracy of SEC. The bivariate mixed-effect model estimated the SEC sensitivity, specificity, diagnostic odds ratio, positive likelihood ratio, and negative likelihood ratio as 73.1%, 99.9%, 7850.6%, 2112.2%, and 0.27%, respectively. Conclusion: Serous effusion cytology shows high specificity and moderate sensitivity in the evaluation of serous effusions. A tiered classification scheme can improve the consistency of terminology for reporting SEC results, thus improving communication between the pathologists and clinical team, and quality of patient care. K E Y W O R D S analysis, classification scheme, comprehensive review, risk of malignancy, serous effusion cytology 1 | INTRODUCTION Serous effusion cytology (SEC) has been widely utilized in the initial evaluation of the etiology of fluid accumulation in the body cavities. Serous fluid can form in body cavities due to various inflammatory, infectious, and benign or malignant neoplasms. Malignancy is the underlying cause of serous effusion in 10% to 61% cases. 1,2 A majority of malignant effusions are caused by metastasis from adenocarcinoma of lung, breast, gastrointestinal, and female genital tract. 2,3 Malignant mesothelioma caninitially present as a serous effusion in up to 10% to 53% cases. 4-8

Introduction: Fine needle aspiration (FNA) has been widely utilized in establishing the nature of salivary gland lesions and guiding the clinical management. This study aimed to determine the accuracy of FNA in detecting salivary gland neoplasms and malignancies, employing the "Milan System for Reporting Salivary Gland Cytopathology" (MSRSGC).Method: A systematic search was conducted. The data on FNA and histologic diagnosis were extracted and categorized based on the MSRSGC and risk of malignancy (ROM) was calculated.The risk of publication bias and level of heterogeneity were evaluated. A mixed-effects model was used to estimate FNA accuracy. Meta-regression was conducted to assess the potential effect of different variables on FNA accuracy.Results: Ninety-two studies with a total of 16 456 FNA with surgical follow-up were included.ROM was estimated as 17%, 8%, 34%, 4%, 42%, 58%, and 91%, in nondiagnostic, nonneoplastic, atypia of undetermined significance, benign neoplasm, salivary gland neoplasm of uncertain malignant potential, suspicious for malignancy, and malignant groups, respectively. High level of heterogeneity was detected (P-value <.001). Including cases with definite FNA diagnosis of neoplasm or malignancy, summary estimates of FNA sensitivity, specificity, diagnostic odds ratio, and positive and negative likelihood ratio in detecting neoplasms and malignancies were 96.9%, 95.3%, 636.8, 20.5, and 0.03, and 80.5%, 97.9%, 189.5, 37.8, and 0.2, respectively. Metaregression showed several variables significantly impacting FNA accuracy; however, subgroup analysis did not reduce the level of heterogeneity.Conclusion: FNA can be used as a reliable diagnostic tool in the preoperative evaluation and management of salivary glands lesions. Concise of abstract is using Milan system for reporting salivary gland FNA could increase FNA reliability, facilitate communication, and improve patient care. K E Y W O R D Sdiagnostic accuracy, FNA, meta-analysis, Milan system for reporting salivary gland cytology, salivary gland malignancy, salivary gland neoplasm

Among several MR imaging features that aid in the discrimination of high-grade from low-grade sarcomas, the presence of peritumoral contrast enhancement is a feature that may be solely used to diagnose high-grade STS.

Background The Milan system for Reporting Salivary Gland Cytopathology (MSRSGC) was published in 2018. Since then, many authors have published their institutional experience by retrospectively assigning salivary gland fine‐needle aspiration cases to each of the MSRSGC categories and calculated their risk of malignancy (ROM) accordingly. Methods We reviewed all published articles available online in English that used the MSRSGC since or near its publication. We calculated the risk of neoplasm and ROM for each diagnostic category. In addition, the false‐negative and false‐positive rates from all studies were examined. Results Thirty‐seven articles were identified in the English literature; 2 were published in 2017, 14 in 2018, 18 in 2019, and 3 in 2020. The total number of cases was 16 394, and 8 468 had surgical follow‐up. The mean ROM was 16.9% for category I, 10.5% for category II, 39.3% for category III, 2.9% for category IVa, 39.4% for category IVb, 84.2% for category V, and 97.5% for category VI. The mean false‐negative rate for MSRSGC categories II and IVa was 4.5%. Similarly, the mean false‐positive rate for MSRSGC categories V and VI was 5.1%. Conclusion A tiered classification scheme of MSRSGC is helpful in effectively guiding clinical management of patients with salivary gland lesions. The reported mean ROM for each category in most studies is within the recommended range published by the MSRSGC.

WBMRN is feasible for use in the clinical practice for the identification and potential characterization of polyneuropathy. J. Magn. Reson. Imaging 2016;44:1513-1521.

• In patients with peripheral neuropathy, MRN significantly impacts diagnostic thinking. • In patients with peripheral neuropathy, MRN significantly impacts therapeutic choices. • 3-T MRN should be considered in presurgical planning of patients with peripheral neuropathy.

Bone marrow lesions on magnetic resonance (MR) imaging are common and may be seen with various pathologies. The authors outline a systematic diagnostic approach with proposed categorization of various etiologies of bone marrow lesions. Utilization of typical imaging features on conventional MR imaging techniques and other problem-solving techniques, such as chemical shift imaging and diffusion-weighted imaging (DWI), to achieve accurate final diagnosis has been highlighted.

MRN of LS plexus is useful modality for the evaluation of patients with non-contributory MRI of lumbar spine as it can incrementally delineate the etiology and provide direct objective and non-invasive evidence of neuromuscular pathology.