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The clinical syndrome of intracranial hypotension refers to the symptoms caused by cerebrospinal fluid hypovolemia and is primarily characterized by postural headaches, but can be associated with a multitude of other neurological symptoms. Imaging plays a critical role in helping to establish a diagnosis of intracranial hypotension, localize the source of cerebrospinal fluid leak, and assist in directing targeted treatments. Using the best available evidence, this document provides diagnostic imaging recommendations for the workup of intracranial hypotension across various clinical presentations. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation., (Copyright © 2024 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Altered mental status (AMS) and coma are terms used to describe disorders of arousal and content of consciousness. AMS may account for up to 4% to 10% of chief complaints in the emergency department setting and is a common accompanying symptom for other presentations. AMS is not a diagnosis, but rather a term for symptoms of acute or chronic disordered mentation, including confusion, disorientation, lethargy, drowsiness, somnolence, unresponsiveness, agitation, altered behavior, inattention, hallucinations, delusions, and psychosis. Some of the most common disorders associated with AMS are underlying medical conditions, substance use, and mental disorders. This document focuses on the appropriateness of neuroimaging in adult patients presenting with AMS changes including new onset delirium or new onset psychosis. In these cases, imaging is often expedited for initial stabilization and to exclude an intracranial process requiring intervention. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation., (Copyright © 2024 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Thoracic back pain is a common site for inflammatory, neoplastic, metabolic, infectious, and degenerative conditions, and may be associated with significant disability and morbidity. Uncomplicated acute thoracic back pain and/or radiculopathy does not typically warrant imaging. Imaging may be considered in those patients who have persistent pain despite 6 weeks of conservative treatment. Early imaging may also be warranted in patients presenting with "red flag" history or symptoms, including those with a known or suspected history of cancer, infection, immunosuppression, or trauma; in myelopathic patients; or in those with a history of prior thoracic spine fusion. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation., (Copyright © 2024 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Competing Interests: The authors have no conflict of interest to declare.

Diagnostic evaluation of a patient with dizziness or vertigo is complicated by a lack of standardized nomenclature, significant overlap in symptom descriptions, and the subjective nature of the patient's symptoms. Although dizziness is an imprecise term often used by patients to describe a feeling of being off-balance, in many cases dizziness can be subcategorized based on symptomatology as vertigo (false sense of motion or spinning), disequilibrium (imbalance with gait instability), presyncope (nearly fainting or blacking out), or lightheadedness (nonspecific). As such, current diagnostic paradigms focus on timing, triggers, and associated symptoms rather than subjective descriptions of dizziness type. Regardless, these factors complicate the selection of appropriate diagnostic imaging in patients presenting with dizziness or vertigo. This document serves to aid providers in this selection by using a framework of definable clinical variants. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation., (Copyright © 2024 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Objectives: Few level I trauma, tertiary care, academic centers have a paid, permanent reading room coordinator (RRC) to facilitate image management services during off-hour calls, to minimize interruptions to reading workflow. The purpose of this study is to investigate the effect of an RRC on the efficiency of radiology residents signing preliminary reports for emergency department (ED) and inpatient studies., Methods: A pre- and postintervention retrospective review was performed, using carestream PACS to retrieve imaging studies read on call during two time periods-July 1 to December 1, 2019 (pre-RRC), and July 1 to December 1, 2021 (post-RRC). Efficiency of residents signing preliminary reports was measured by turnaround time (TAT), defined as the time from when a study was marked complete by a technologist to when a preliminary report was signed by a resident, in PACS., Results: In the above time periods, residents interpreted a total of 64,406 studies on call. For ED studies, the mean TAT was 7.0 min shorter post-RRC, compared with pre-RRC (95% confidence interval [CI]: -7.8 to -6.1, (t = 15.50, degrees of freedom (df) = 31,866, P < .0001). The percentage of ED studies signed within 30 min increased from 57.7% to 65.8%, an increase of 8.1% (95% CI: 7.0% to 9.1%) after employing an RRC (χ 2  = 228.11, df = 1, P < .0001). For inpatient studies, the mean TAT was 10.2 min shorter post-RRC (95% CI: -12.3 to -8.0, t = 9.22, df = 25,193, P < .0001)., Conclusions: An RRC increased radiology resident on-call workflow efficiency, facilitating care for patients in both the ED and inpatient setting., (Copyright © 2023 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Objectives: The Salivary Gland Committee of the American Academy of Otolaryngology-Head and Neck Surgery seeks to standardize terminology and technique for ultrasonograpy used in the evaluation and treatment of salivary gland disorders., Methods: Development of expert opinion obtained through interaction with international practitioners representing multiple specialties. This committee work includes a comprehensive literature review with presentation of case examples to propose a standardized protocol for the language used in ultrasound salivary gland assessment., Results: A multiple segment proposal is initiated with this focus on the submandibular gland. We provide a concise rationale for recommended descriptive language highlighted by a more extensive supplement that includes an extensive literature review with additional case examples., Conclusion: Recommendations are provided to improve consistency both in performing and reporting submandibular gland ultrasound., Competing Interests: Hoffman H: Henry T. Hoffman: (a) COOK Medical: Research consultant. (b) UpToDate author. Ryan W: scientific advisory boards for Olympus and Rakuten Medical and consultant for C2DX. Donato F: TriSalus advisory board member. No conflicts of interest related to this publication. Bertelli A: Speaker and travel grants for Merck. Anderson C: former compensated now uncompensated since 2013 consultant for Galera Therapeutics since 2013: research funding from Soligenix; research funding from Galera Therapeutics., (© 2024 The Authors. Laryngoscope Investigative Otolaryngology published by Wiley Periodicals LLC. on behalf of The Triological Society.)

Imaging of head and neck cancer at initial staging and as part of post-treatment surveillance is a key component of patient care as it guides treatment strategy and aids determination of prognosis. Head and neck cancer includes a heterogenous group of malignancies encompassing several anatomic sites and histologies, with squamous cell carcinoma the most common. Together this comprises the seventh most common cancer worldwide. At initial staging comprehensive imaging delineating the anatomic extent of the primary site, while also assessing the nodal involvement of the neck is necessary. The treatment of head and neck cancer often includes a combination of surgery, radiation, and chemotherapy. Post-treatment imaging is tailored for the evaluation of treatment response and early detection of local, locoregional, and distant recurrent tumor. Cross-sectional imaging with CT or MRI is recommended for the detailed anatomic delineation of the primary site. PET/CT provides complementary metabolic information and can map systemic involvement. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment., (Copyright © 2023 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Tinnitus is abnormal perception of sound and has many subtypes. Clinical evaluation, audiometry, and otoscopy should be performed before ordering any imaging, as the choice of imaging will depend on various factors. Type of tinnitus (pulsatile or nonpulsatile) and otoscopy findings of a vascular retrotympanic lesion are key determinants to guide the choice of imaging studies. High-resolution CT temporal bone is an excellent tool to detect glomus tumors, abnormal course of vessels, and some other abnormalities when a vascular retrotympanic lesion is seen on otoscopy. CTA or a combination of MR and MRA/MRV are used to evaluate arterial or venous abnormalities like dural arteriovenous fistula, arteriovenous malformation, carotid stenosis, dural sinus stenosis, and bony abnormalities like sigmoid sinus wall abnormalities in cases of pulsatile tinnitus without a vascular retrotympanic lesion. MR of the brain is excellent in detecting mass lesions such as vestibular schwannomas in cases of unilateral nonpulsatile tinnitus. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation., (Copyright © 2023 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Objectives: To assess the adequacy of gadolinium in sialography as an alternative contrast agent for patients with iodine allergies. To directly compare images taken with gadolinium versus iodine-based contrast agents using the Iowa Sialography Classification System., Methods: Retrospective chart review was performed on patients undergoing sialography between February 2008 and July 2022. Patients with sialograms obtained with gadolinium were identified and matched to similar sialograms obtained with iodine-based contrast agent. Patients were matched based on duct location, duct side, and initial radiology findings. Blinded reevaluation of sialograms was performed first independently and then by consensus by two head and neck radiologists to evaluate overall image adequacy and grade using the Iowa Sialography Classification System., Results: Four patients with six sialograms (one bilateral parotid and one parotid + submandibular) obtained with gadolinium were identified and reevaluated. Five patients with six sialograms (one bilateral parotid) obtained with iodine-based were matched to the gadolinium sialograms. The overall adequacy of images for gadolinium sialograms was graded at an average of 4.25 (4 = good and 5 = excellent); whereas, the overall adequacy of iodine-based sialograms was graded at an average of 5. Inter-observer variability was observed in three sialograms obtained with gadolinium (50%), while no interobserver variability was observed in sialograms obtained with iodine-based contrast agent., Conclusion: Gadolinium is an adequate alternative to use in sialography for patients with iodine allergies undergoing contemporary digital infusion sialography. Adverse reactions to iodine contrast agents are rare in sialography; however, the precautionary use of gadolinium is acceptable for the diagnostic and therapeutic benefits in sialography.Level of Evidence: IV., Competing Interests: Dr. Henry T. Hoffman reported personal fees as an author from UpToDate and personal fees as a research consultant from Cook Medical outside the submitted work., (© 2023 The Authors. Laryngoscope Investigative Otolaryngology published by Wiley Periodicals LLC on behalf of The Triological Society.)

Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Cranial neuropathy can result from pathology affecting the nerve fibers at any point and requires imaging of the entire course of the nerve from its nucleus to the end organ in order to identify a cause. MRI with and without intravenous contrast is often the modality of choice with CT playing a complementary role. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation., (Copyright © 2022 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Maxillofacial trauma patients comprise a significant subset of patients presenting to emergency departments. Before evaluating for facial trauma, an emergency or trauma physician must perform a primary survey to ensure patient stabilization. Following this primary survey, this document discusses the following clinical scenarios for facial trauma: tenderness to palpation or contusion or edema over frontal bone (suspected frontal bone injury); pain with upper jaw manipulation or pain overlying zygoma or zygomatic deformity or facial elongation or malocclusion or infraorbital nerve paresthesia (suspected midface injury); visible nasal deformity or palpable nasal deformity or tenderness to palpation of the nose or epistaxis (suspected nasal bone injury); and trismus or malocclusion or gingival hemorrhage or mucosal hemorrhage or loose teeth or fractured teeth or displaced teeth (suspected mandibular injury). The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment., (Copyright © 2022 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

This article presents guidelines for initial imaging utilization in patients presenting with sinonasal disease, including acute rhinosinusitis without and with suspected orbital and intracranial complications, chronic rhinosinusitis, suspected invasive fungal sinusitis, suspected sinonasal mass, and suspected cerebrospinal fluid leak. CT and MRI are the primary imaging modalities used to evaluate patients with sinonasal disease. Given its detailed depiction of bony anatomy, CT can accurately demonstrate the presence of sinonasal disease, bony erosions, and anatomic variants, and is essential for surgical planning. Given its superior soft tissue contrast, MRI can accurately identify clinically suspected intracranial and intraorbital complications, delineate soft tissue extension of tumor and distinguish mass from obstructed secretions.The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment., (Copyright © 2022 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Background and Purpose: Multidetector CT is the workhorse for detecting blunt cervical spine injury. There is no standard of care for re-interpretation of radiology images for patients with blunt trauma transferred to a higher level of care. The clinical impact of discrepancies of cervical spine CT reads remains unclear. We evaluated the discordance between primary (from referring hospitals) and secondary radiology interpretations (from a receiving level I tertiary trauma center) of cervical spine CT scans in patients with blunt trauma and assessed the clinical implications of missed cervical spine fractures., Materials and Methods: Medical records of patients with blunt trauma transferred to our institution between 2008 and 2015 were reviewed. Primary and secondary interpretations were compared and categorized as concordant and discordant. Two senior neuroradiologists adjudicated discordant reports. The benefit of re-interpretation was determined. For discordant cases, outcomes at discharge, injury severity pattern, treatment, and arrival in a cervical collar were assessed., Results: Six hundred fifty patients were included; 608 (94%) presented with concordant reports: 401 (61.7%) with fractures and 207 (31.8%) with no fractures. There were 42 (6.5%) discordant reports; 18 (2.8%) were cervical spine injuries undetected on the primary interpretation. Following adjudication, the secondary interpretation improved the sensitivity (99.3% versus 95.7%) and specificity (99.1% versus 91.7%) in detecting cervical spine fractures compared with the primary interpretation alone ( P  < .001)., Conclusions: There was an overall 6.5% discordance rate between primary and secondary interpretations of cervical spine CT scans. The secondary interpretation of the cervical spine CT increased the sensitivity and specificity of detecting cervical spine fractures in patients with blunt trauma transferred to higher-level care., (© 2021 by American Journal of Neuroradiology.)

Hyperparathyroidism is defined as excessive parathyroid hormone production. The diagnosis is made through biochemical testing, in which imaging has no role. However, imaging is appropriate for preoperative parathyroid gland localization with the intent of surgical cure. Imaging is particularly useful in the setting of primary hyperparathyroidism whereby accurate localization of a single parathyroid adenoma can facilitate minimally invasive parathyroidectomy. Imaging can also be useful to localize ectopic or supernumerary parathyroid glands and detail anatomy, which may impact surgery. This document summarizes the literature and provides imaging recommendations for hyperparathyroidism including primary hyperparathyroidism, recurrent or persistent primary hyperparathyroidism after parathyroid surgery, secondary hyperparathyroidism, and tertiary hyperparathyroidism. Recommendations include ultrasound, CT neck without and with contrast, and nuclear medicine parathyroid scans. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment., (Copyright © 2021 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Objectives/hypothesis: To apply a novel sialography classification system to identify parotid and submandibular ductal findings following I-131 therapy and to assess correlates to dose and duration of symptoms., Study Design: Retrospective single-center case series., Methods: Patients who underwent sialography between February 2008 and February 2019 after previously receiving I-131 treatment were identified via a retrospective chart review. Their sialograms were systematically evaluated and scored by applying the Iowa parotid sialogram scale to also include submandibular gland analysis., Results: From 337 sialograms, 30 (five submandibular, 25 parotid) underwent analysis. Ductal stenosis was identified in all sialograms and was graded as moderate (>50%-75%) in 7/30 cases and severe (>75%) in 15/30 cases. The distal (main) duct was narrowed in 23/30 cases. No association was identified between degree of ductal stenosis and I-131 dose (P = .39), age (P = .81), or time from I-131 therapy to sialogram (P = .97)., Conclusions: The Iowa parotid sialogram scale was successfully applied to report abnormalities of the parotid and submandibular ductal system. The most common manifestation of I-131-associated sialadenitis was a severe stenosis within the distal salivary duct. No statistically significant association was found between degree of ductal stenosis and dose of I-131, age, or duration of symptoms., Level of Evidence: 4 Laryngoscope, 131:E1450-E1456, 2021., (© 2020 American Laryngological, Rhinological and Otological Society Inc, "The Triological Society" and American Laryngological Association (ALA).)

Syncope and presyncope lead to well over one million emergency room visits in the United States each year. Elucidating the cause of syncope or presyncope, which are grouped together given similar etiologies and outcomes, can be exceedingly difficult given the diverse etiologies. This becomes more challenging as some causes, such as vasovagal syncope, are relatively innocuous while others, such as cardiac-related syncope, carry a significant increased risk of death. While the mainstay of syncope and presyncope assessment is a detailed history and physical examination, imaging can play a role in certain situations. In patients where a cardiovascular etiology is suspected based on the appropriate history, physical examination, and ECG findings, resting transthoracic echocardiography is usually considered appropriate for the initial imaging. While no imaging studies are considered usually appropriate when there is a low probability of cardiac or neurologic pathology, chest radiography may be appropriate in certain clinical situations. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment., (Copyright © 2021 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Background: To compare the computed tomography perfusion (CTP) outcomes derived from two commercial CTP processing software and evaluate their concordance in terms of eligibility for mechanical thrombectomy (MT) in acute ischemic stroke (AIS), based on DEFUSE III criteria., Methods: A total of 118 patients (62 patients in the MT group and 56 patients in the non-MT (NMT) group) were included. Volumetric perfusion outputs were compared between Syngo.via (package A) and RAPID (package B). Influence on proceeding or not-proceeding with MT was based on DEFUSE III imaging eligibility criteria., Results: Median core infarct/hypoperfusion volumes were 12.3/126 mL in the MT group and 7.7/29.3 ml in the NMT group with package A and 10.5/138 mL and 1.9/24.5 mL with package B, respectively. In the MT group (n=62), concordant perfusion results in terms of patient triage were noted in all but two cases. Of these, one patient would not have qualified (low ASPECTS), while the other qualified based on package A results. For the NMT group (n=56), there was discordance in terms of MT eligibility in seven cases. However, none of these patients qualified for MT based on DEFUSE III criteria., Conclusions: Both perfusion softwares showed high concordance in correctly triaging patients in the MT versus NMT groups (110/118, 93.2%), which further improved when all DEFUSE III imaging criteria were considered (117/118, 99.1%). The core/hypoperfusion volumes in the NMT group and core infarct volumes in the MT groups were comparable. The hypoperfusion volumes in the MT group varied slightly but did not affect triage between groups., Competing Interests: Competing interests: EK and MJ are full-time employees of Siemens AG, Forchheim, Germany., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: To analyze the location and degree of parotid ductal abnormalities associated with Sjogren's syndrome (SS) and to correlate findings with the duration of the disease. To develop a classification system based on contemporary sialography techniques and employ the system to grade findings on sialograms. To assess the role for therapeutic intervention in patients with SS., Methods: Retrospective chart review of a consecutive series of 337 sialograms done by the senior investigator over a 10-year period identified 26 sialograms in patients who met the criteria for SS as defined by the American-European Consensus Group (2002). A classification system was developed to grade the degree of ductal abnormalities identified on the sialograms. Individual, initial blinded review of these sialograms was performed by two head and neck radiologists to identify and grade abnormalities. Radiographic findings were correlated with patient history including symptom duration., Results: All patients with SS had stenoses within the ductal system. About 73.1% of patients had stenoses in each branch of the ductal system (primary, secondary, and tertiary ducts). In 19% of patients, the main duct was of normal caliber despite the presence of stenosis in the more proximal ducts (secondary and tertiary ducts). Peripheral (proximal) duct dilation was characterized among those affected in patterns classified as destructive (34.6%), cavitary (26.9%), globular (11.5%), or punctate (11.5%). A statistically significant positive correlation (p = .0360) was identified between symptom duration and degree of main ductal stenosis., Conclusion: Sialography may be useful to objectively assess the degree of parotid ductal damage in SS employing a newly proposed classification system. This assessment may assist clinicians in tailoring management to selectively include ductal dilation., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved.)

The ACR recognizes that radiology practices are grappling with when and how to safely resume routine radiology care during the coronavirus disease 2019 (COVID-19) pandemic. Although it is unclear how long the pandemic will last, it may persist for many months. Throughout this time, it will be important to perform safe, comprehensive, and effective care for patients with and patients without COVID-19, recognizing that asymptomatic transmission is common with this disease. Local idiosyncrasies prevent a single prescriptive strategy. However, general considerations can be applied to most practice environments. A comprehensive strategy will include consideration of local COVID-19 statistics; availability of personal protective equipment; local, state, and federal government mandates; institutional regulatory guidance; local safety measures; health care worker availability; patient and health care worker risk factors; factors specific to the indication(s) for radiology care; and examination or procedure acuity. An accurate risk-benefit analysis of postponing versus performing a given routine radiology examination or procedure often is not possible because of many unknown and complex factors. However, this is the overriding principle: If the risk of illness or death to a health care worker or patient from health care-acquired COVID-19 is greater than the risk of illness or death from delaying radiology care, the care should be delayed; however, if the opposite is true, the radiology care should proceed in a timely fashion., (Copyright © 2020 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

The Response Assessment in Neuro-Oncology criteria were developed as an objective tool for radiologic assessment of treatment response in high-grade gliomas. Imaging plays a critical role in the management of the patient with glioma, from initial diagnosis to posttreatment follow-up, which can be particularly challenging for radiologists. Interpreting findings after surgery, radiation, and chemotherapy requires profound knowledge about the tumor biology, as well as the peculiar changes expected to ensue as a consequence of each treatment technique. In this article, we discuss the imaging findings associated with tumor progression, tumor response, pseudoprogression, and pseudoresponse according to the Response Assessment in Neuro-Oncology criteria for high-grade and lower-grade gliomas. We describe relevant practical issues when evaluating patients with glioma, such as the need for imaging in the first 48 hours, the radiation therapy planning and isodose curves, the significance of T2/FLAIR hyperintense lesions, the impact of the timing for the evaluation after radiation therapy, and the definition of progressive disease on the histologic specimen. We also illustrate the correlation among the findings on conventional MR imaging with advanced techniques, such as perfusion, diffusion-weighted imaging, spectroscopy, and amino acid PET. Because many of the new lesions represent a mixture of tumor cells and tissue with radiation injury, the radiologist aims to identify the predominant component of the lesion and categorize the findings according to Response Assessment in Neuro-Oncology criteria so that the patient can receive the best treatment., (© 2020 by American Journal of Neuroradiology.)

Background: Computed tomography angiogram (CTA) derived from computed tomography perfusion (CTP) has been proposed to avoid addition of separate CT perfusion protocol for selection of large vessel occlusion in acute stroke patients. Previous studies have validated this technique for proximal large vessel occlusions. In this study, we test reliability for identifying M2 occlusions on CTA derived from CTP., Methods: Through a retrospective search of the institutional thrombectomy database, we identified 28 cases with M2-MCA occlusion, of which 24 met the inclusion criteria for analysis. An additional 20 cases without M2-MCA occlusion (either normal or M1-MCA occlusion) were randomly mixed in the database to reduce observer bias. The baseline images of the CTP study in these 48 cases were then independently analyzed by 3 readers with varying level of expertise. The digital subtraction angiography (DSA) images were also independently reviewed where available. The percentage of agreement among reviewers as well as the probability of agreement of the reviewers, when compared to the DSA findings was also calculated., Results: The observed agreement for the image quality amongst the 3 readers (n = 48) varied between 0.78 and 0.95 and tended to be higher for the M1 segment MCA and lower for distal M2-MCA. The observed agreements comparing 3 image reviewers versus DSA in M2 patients (n = 24) was 98% for identifying occlusion (95% CI 95%-100%), 94% for identifying proximal M2 occlusion (95% CI 88%-98%), and 91% (95% CI 84%-97%) and 90% (95% CI 83%-95%), respectively for correctly identifying inferior and superior branch of M2 occlusion., Conclusion: CTA data derived from CT Perfusion study preserves diagnostic yield for correctly identifying M2 occlusion., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: The role of mechanical thrombectomy in acute ischemic stroke (AIS) has been further expanded by recent trials which relied on the results of CT perfusion (CTP) imaging. However, CTP parameters for ischemia and infarct can vary significantly across different vendors., Methods: We compared the outcomes of the Siemens CTP software against the clinically validated RAPID software in 45 consecutive patients with suspected AIS. Both perfusion softwares initially processed images using vendor defined parameters for hypoperfusion and non-viable tissue. The software thresholds on the Siemens software were decrementally altered to see if concordant results between softwares could be attained., Results: At baseline settings, the mean values for core infarct and hypoperfusion were different (mean of 30/69 mL, respectively, for RAPID and 49/77 mL for Siemens). However, reducing the threshold values for the later software showed a concordance of values at a relative cerebral blood flow <20%, with resulting core infarct and hypoperfusion volumes at 31/69 mL, respectively, for the Siemens software. A Wilcoxon paired test showed no significant difference between the calculated core infarct and hypoperfusion values, both for the entire population as well as for the subgroup of patients with large vessel occlusion., Conclusion: Equivalent CTP results between vendor softwares may be attainable by altering the thresholds for hypoperfused and non-viable tissue, despite differences in acquisition techniques, post-processing, and scanners., Competing Interests: Competing interests: EK and MJ are full time employees of Siemens AG, Forchheim, Germany., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Headache is one of the most common human afflictions. In most cases, headaches are benign and idiopathic, and resolve spontaneously or with minor therapeutic measures. Imaging is not required for many types of headaches. However, patients presenting with headaches in the setting of "red flags" such as head trauma, cancer, immunocompromised state, pregnancy, patients 50 years or older, related to activity or position, or with a corresponding neurological deficit, may benefit from CT, MRI, or noninvasive vascular imaging to identify a treatable cause. This publication addresses the initial imaging strategies for headaches associated with the following features: severe and sudden onset, optic disc edema, "red flags," migraine or tension-type, trigeminal autonomic origin, and chronic headaches with and without new or progressive features. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment., (Copyright © 2019 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Background and Purpose: To evaluate the accuracy and inter-observer variability when CT angiography is used to identify unruptured intracranial aneurysm growth., Methods: Two silicone phantom models were used in this study. Each phantom had eight aneurysms of variable size. The size and location of aneurysms in phantom 1 were representative of real patient aneurysms who presented to our institution. Phantom 2 contained aneurysms in the same locations, but with enlargement in various directions. Three blinded board-certified neuroradiologists were asked to identify the size of each aneurysm in three dimensions using CT angiography. The individual enlargement detection rates and inter-observer agreement rates of aneurysm enlargement among the three experts were calculated., Results: The detection rate of aneurysm enlargement in one dimension was 58.3% among the three observers. Accurate detection of enlargement in all dimensions was 12.5% among the three observers. Detection accuracy was not related to the size of enlargement. Significant inter-observer measurement variability was present., Conclusion: The use of CT angiography was associated with a poor ability to identify aneurysm enlargementaccurately. Further human studies are required to confirm our findings., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Ataxia can result from an abnormality in the cerebellum, spinal cord, peripheral nerves, and/or vestibular system. Pathology involving the brain, such as infarct or hydrocephalus, can also present with ataxia as part of the symptom constitution, or result in symptoms that mimic ataxia. Clinical evaluation by history and careful neurological examination is important to help with lesion localization, and helps determine where imaging should be focused. In the setting of trauma with the area of suspicion in the brain, a head CT without intravenous contrast is the preferred initial imaging choice. If vascular injury is suspected, CTA of the neck can be helpful. When the area of suspicion is in the spine, CT or MRI of the spine can be considered to assess for bony or soft-tissue injury, respectively. In the setting of ataxia unrelated to recent trauma, MRI is the preferred imaging modality, tailored to assess the brain or spine depending on the area of suspected pathology. The use of intravenous contrast is generally helpful. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment., (Copyright © 2019 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

There are a wide variety of diseases that affect the thyroid gland ranging from hyperplastic to neoplastic, autoimmune, or inflammatory. They can present with functional abnormality or a palpable structural change. Imaging has a key role in diagnosing and characterizing the thyroid finding for management. Imaging is also essential in the management of thyroid cancer. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment., (Copyright © 2019 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Neuroendocrine dysfunction includes suspected hyper- and hypofunction of the pituitary gland. Causative lesions may include primary masses of the pituitary such as pituitary microadenomas and macroadenomas, as well as extrinsic masses, typically centered in the suprasellar cistern. Clinical syndromes related to hormonal dysfunction can be caused by excessive hormonal secretion or by inhibited secretion due to mass effect upon elements of the hypothalamic-pituitary axis. Additionally, complications such as hemorrhage may be seen in the setting of an underlying mass and can result in hormonal dysfunction. MRI with high-resolution protocols is the best first-line test to evaluate the sella turcica and parasellar region. CT provides complementary information regarding bony anatomy, and may be appropriate as a first-line test in certain instances, but it provides less detail and lesion characterization when compared to MRI. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment., (Copyright © 2019 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

A palpable neck mass may be the result of neoplastic, congenital, or inflammatory disease. Older age suggests neoplasia, and a congenital etiology is more prevalent in the pediatric population. The imaging approach is based on the patient age, mass location, and clinical pulsatility. Underlying human papillomavirus-related malignancy should be considered in all age groups. Although the imaging appearance of some processes in the head and neck overlap, choosing the appropriate imaging examination may allow a specific diagnosis, or a limited differential diagnosis. Tissue sampling is indicated to confirm suspected malignancy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment., (Copyright © 2019 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Inflammatory disease of the paranasal sinuses is extremely common and the course is often innocuous. However, when extrasinus spread of disease occurs life-threatening complications can arise. Intraorbital and intracranial involvement can progress rapidly either by hematogenous spread or in the case of fungal sinusitis via angioinvasion. An understanding of anatomy and appropriate imaging protocols is critical when these complications arise. The knowledge of imaging features of the different disease processes and prompt diagnosis is essential to improve patient outcomes and positively impact patient care., (Copyright © 2018 Elsevier Inc. All rights reserved.)