Retinal and optic nerve magnetic resonance diffusion-weighted imaging in acute non-arteritic central retinal artery occlusion.

OBJECTIVES: Diffusion weighted imaging hyperintensity (DWI-H) has been described in the retina and optic nerve during acute central retinal artery occlusion (CRAO). We aimed to determine whether DWI-H can be accurately identified on standard brain magnetic resonance imaging (MRI) in non-arteritic CRAO patients at two tertiary academic centers. MATERIALS AND METHODS: Retrospective cross-sectional study that included all consecutive adult patients with confirmed acute non-arteritic CRAO and brain MRI performed within 14 days of CRAO. At each center, two neuroradiologists masked to patient clinical data reviewed each MRI for DWI-H in the retina and optic nerve, first independently then together. Statistical analysis for inter-rater reliability and correlation with clinical data was performed. RESULTS: We included 204 patients [mean age 67.9±14.6 years; 47.5% females; median time from CRAO to MRI 1 day (IQR 1-4.3); 1.5 T in 127/204 (62.3%) and 3.0 T in 77/204 (37.7%)]. Inter-rater reliability varied between centers (κ = 0.27 vs. κ = 0.65) and was better for retinal DWI-H. Miss and error rates significantly differed between neuroradiologists at each center. After consensus review, DWI-H was identified in 87/204 (42.6%) patients [miss rate 117/204 (57.4%) and error rate 11/87 (12.6%)]. Significantly more patients without DWI-H had good visual acuity at follow-up (p = 0.038). CONCLUSIONS: In this real-world case series, differences in agreement and interpretation accuracy among neuroradiologists limited the role of DWI-H in diagnosing acute CRAO on standard MRI. DWI-H was identified in 42.6% of patients and was more accurately detected in the retina than in the optic nerve. Further studies are needed with standardized novel MRI protocols.

PET/CT for Head and Neck Squamous Cell Carcinoma: Should We Routinely Include the Head and Abdomen?

OBJECTIVE: The purpose of our study was to determine the diagnostic and therapeutic yield of the head and abdomen portions of PET/CT scans of patients with head and neck squamous cell cancer (HNSCC) to determine whether these areas should be routinely included with PET/CT of the neck and chest. MATERIALS AND METHODS: Patients with pathologically proven HNSCC who underwent full-body PET/CT were evaluated for metastases to the head, chest, and abdomen. Medical records were reviewed to determine whether the head and abdominal findings changed the clinical management, beyond the findings in the neck and chest. RESULTS: Five hundred ninety-eight patients who underwent 1625 PET/CT scans were included. All studies included the head, neck, and chest. For 542 of 598 patients (91%), the PET/CT scans included the abdomen. Two of 598 patients (0.3%) had distant calvarial metastases. Neither of the calvarial metastases changed patient management. Twelve of 542 patients (2.2%) had abdominal metastases. For 10 of 542 patients (1.8%), the abdominal findings changed patient management. Thoracic metastases were found in 82 of 598 patients (13.7%). The total rate of distant metastases to the head and abdomen in patients with thoracic metastatic disease was 12.2% (10/82), whereas in patients without thoracic metastases, it was 0.8% (4/460). CONCLUSION: Routine extension of PET/CT scans to include the head and abdomen in patients with HNSCC is not indicated. For patients without evidence of thoracic metastases, routine PET/CT examinations should include the neck and chest only.

Bacterial, Viral, and Prion Infectious Diseases of the Brain.

Diagnosis of brain infections is based on a combination of clinical features, laboratory markers, and imaging findings. Imaging characterizes the extent and severity of the disease, aids in guiding diagnostic and therapeutic procedures, monitors response to treatment, and demonstrates complications. This review highlights the characteristic imaging manifestations of bacterial and viral infections in the brain.

Bacterial and Viral Infectious Disease of the Spine.

Spinal infections are a diverse group of diseases affecting different compartments of the spine with variable clinical and imaging presentations. Diagnosis of spinal infections is based on a combination of clinical features, laboratory markers, and imaging studies. Imaging plays a pivotal role in the diagnosis and management of spinal infections. The characteristic imaging manifestations of bacterial and viral infections in the spine are discussed with key teaching points emphasized.

Does Long-term Surveillance Imaging Improve Survival in Patients Treated for Head and Neck Squamous Cell Carcinoma? A Systematic Review of the Current Evidence.

BACKGROUND: Long-term post-treatment surveillance imaging algorithms for head and neck squamous cell carcinoma are not standardized due to debates over optimal surveillance strategy and efficacy. Consequently, current guidelines do not provide long-term surveillance imaging recommendations beyond 6 months. PURPOSE: We performed a systematic review to evaluate the impact of long-term imaging surveillance (i.e., imaging beyond 6 months following treatment completion) on survival in patients treated definitively for head and neck squamous cell carcinoma. DATA SOURCES: A search was conducted on PubMed, Embase, Scopus, the Cochrane Central Register of Controlled Trials, and Web of Science for English literature published between 2003 and 2024 evaluating the impact of long-term surveillance imaging on survival in patients with head and neck squamous cell carcinoma. STUDY SELECTION: 718 abstracts were screened and 95 underwent full-text review, with 2 articles meeting inclusion criteria. The Risk of Bias in Non-randomized Studies of Interventions assessment tool was used. DATA ANALYSIS: A qualitative assessment without a pooled analysis was performed for the two studies meeting inclusion criteria. DATA SYNTHESIS: No randomized prospective controlled trials were identified. Two retrospective two-arm studies were included comparing long-term surveillance imaging with clinical surveillance and were each rated as having moderate risk of bias. Each study included heterogeneous populations with variable risk profiles and imaging surveillance protocols. Both studies investigated the impact of long-term surveillance imaging on overall survival and came to a different conclusion with one study reporting a survival benefit for long-term surveillance imaging with FDG PET/CT in patients with stage III or IV disease or an oropharyngeal primary tumor and the other study demonstrating no survival benefit. LIMITATIONS: Limited heterogeneous retrospective data available precludes definitive conclusions on the impact of long-term surveillance imaging in head and neck squamous cell carcinoma. CONCLUSIONS: There is insufficient quality evidence regarding the impact of long-term surveillance imaging on survival in patients treated definitively for head and neck squamous cell carcinoma. There is a lack of standardized definition of long-term surveillance, variable surveillance protocols, and inconsistencies in results reporting, underscoring the need for a prospective multi-center registry assessing outcomes. ABBREVIATIONS: HNSCC = Head and Neck Squamous Cell Carcinoma; RT= radiotherapy; NCCN = National Comprehensive Cancer Network; MPC = metachronous primary cancer; CR = complete response; OS = overall survival; CRT = chemoradiotherapy; HPV = human papillomavirus; PFS = progression-free survival; CFU = clinical follow up; NI-RADS = Neck Imaging Reporting and Data System.

Imaging approach for jaw and maxillofacial bone tumors with updates from the 2022 World Health Organization classification.

Jaw and maxillofacial bone lesions encompass a wide variety of both neoplastic and non-neoplastic pathologies. These lesions can arise from various tissues, including bone, cartilage, and soft tissue, each presenting distinct challenges in diagnosis and treatment. While some pathologies exhibit characteristic imaging features that aid in diagnosis, many others are nonspecific. This overlap often necessitates a multimodal imaging approach, combining techniques such as radiographs, computed tomography, and magnetic resonance imaging to achieve a diagnosis or narrow the diagnostic considerations. This article provides a comprehensive review of the imaging approach to jaw and maxillofacial bone tumors, including updates on the 2022 World Health Organization classification of these tumors. The relevant anatomy of the jaw and dental structures that is important for accurate imaging interpretation is discussed.

CT Imaging of Eustachian Tube Balloon Dilation: Method Development on Cadaver Heads.

Objective: To develop a methodology for the measurement of balloon dilation (BD) effects on Eustachian Tube (ET) structure using Computerized Tomography (CT) images. Methods: The BD of the ET was performed on three cadaver heads (five ears) through the nasopharyngeal orifice. The axial CT images of the temporal bones were obtained before dilation, while an inflated balloon was in the lumen of ET, and after balloon removal in each ear. Utilizing Dicom images captured by the ImageJ software 3D volume viewer function, the anatomical landmark coordinates of the ET were matched with their pre- and post-dilation counterparts, and the longitudinal axis of the ET was captured with serial images. The histograms of the regions of interest (ROI) and three different lumen width and length measurements were obtained from captured images. The densities of air, tissue, and bone were determined with histograms as a baseline to determine the BD rate as a function of increased air in the lumen. Results: The small ROI box included the area of prominently dilated ET lumen after BD and best represented the visually obvious changes in the lumen, compared to the ROIs that extended the wider areas (longest and longer). Air density was the outcome measure for comparison with each corresponding baseline value. The average increase in air density in the small ROI was 64%, while the longest and long ROI boxes showed 44 and 56% increases, respectively. Conclusion: This study describes a method to image the ET and quantify the outcomes of BD of the ET using anatomical landmarks.

ACR Appropriateness Criteria® Staging and Post-Therapy Assessment of Head and Neck Cancer.

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.

ACR Appropriateness Criteria® Tinnitus: 2023 Update.

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.

Craniofacial Chondromyxoid Fibromas: A Systematic Review and Analysis Based on Anatomic Locations.

BACKGROUND: Craniofacial chondromyxoid fibromas (CMFs) are a rare benign tumor of cartilaginous origin. They are commonly misdiagnosed due to the paucity of information on tumor characteristics. We performed a systematic review to characterize CMFs located in different regions of the craniofacial skeleton. METHODS: A search of the literature was executed using the search phrase "chondromyxoid fibroma" and included articles from 1990-2020. Sixty-eight articles met the inclusion criteria, with a total of 91 patients with analyzable data (22 with calvarial and 69 with sinonasal tumor locations). Descriptive analyses were performed to compare pre-selected characteristics between the 2 groups. RESULTS: Sinonasal CMF frequently presented with cranial nerve palsy and expectedly had a high rate of nasal symptoms. Calvarial tumors frequently presented with an external mass and headache. Gross total resection (GTR) was achieved in a higher proportion of cases in the calvarial group versus the sinonasal group (83.3% vs. 53.1%). Overall recurrence rate at 17.7% was higher in sinonasal CMF compared with the calvarial tumors at 8.3%. Recurrences after GTR were similar in the sinonasal and calvarial groups (9.7% vs. 9.1%). In patients who did not achieve GTR, recurrence was higher in the sinonasal compared with the calvarial group (27.6% vs. 0%). CONCLUSIONS: Craniofacial CMF in calvarial and sinonasal locations have distinct clinical characteristics and response to treatment. Sinonasal lesions tend to have higher recurrence compared to calvarial CMF. Performance of GTR is associated with decreased recurrence in all CMFs.

Association of meningitis and clival canal defect: case illustration, management, and systematic review of the literature.

OBJECTIVE: Improper embryological development of the clivus, a bony structure that comprises part of the skull base, can lead to a clival canal defect. Previously thought to be a benign condition, clival canals have been reported to be associated with meningitis and meningoceles. In this review, the authors sought to present an unpublished case of a patient with a clival canal defect associated with meningitis and to evaluate all other reported cases. METHODS: In October 2020, a search of PubMed, Web of Science, and Scopus was conducted to identify all cases of clival canals reported from January 1, 1980, through October 31, 2020. RESULTS: Including the case presented herein, 13 cases of clival canals, 11 in children (84.6%) and 2 in adults (15.4%), have been identified. Of the pediatric patients, 5 (45.5%) had an associated meningocele, and 8 (72.7%) had meningitis. Nine of the 13 patients (69.2%) had defects that were treated surgically, 5 (38.5%) by a transnasal approach and 4 (30.8%) by a transoral approach. Two patients (15.4%) were treated with drainage and antibiotics, 1 patient (7.7%) was treated solely with antibiotics, and 1 patient (7.7%) was not treated. In the literature review, 8 reports of clival canals were found to be associated with meningitis, further contributing to the notion that the clival canal may be an overlooked source of recurrent infection. In several of these cases, surgical repair of the lesion was curative, thus preventing continued episodes of meningitis. CONCLUSIONS: When a patient has recurrent meningitis with no clear cause, taking a closer look at clival anatomy is recommended. In addition, if a clival canal defect has been identified, surgical repair should be considered a safe and effective primary treatment option.

Advanced MRI Protocols to Discriminate Glioma From Treatment Effects: State of the Art and Future Directions.

In the follow-up treatment of high-grade gliomas (HGGs), differentiating true tumor progression from treatment-related effects, such as pseudoprogression and radiation necrosis, presents an ongoing clinical challenge. Conventional MRI with and without intravenous contrast serves as the clinical benchmark for the posttreatment surveillance imaging of HGG. However, many advanced imaging techniques have shown promise in helping better delineate the findings in indeterminate scenarios, as posttreatment effects can often mimic true tumor progression on conventional imaging. These challenges are further confounded by the histologic admixture that can commonly occur between tumor growth and treatment-related effects within the posttreatment bed. This review discusses the current practices in the surveillance imaging of HGG and the role of advanced imaging techniques, including perfusion MRI and metabolic MRI.

ACR Appropriateness Criteria® Sinonasal Disease: 2021 Update.

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.

ACR Appropriateness Criteria® Cranial Neuropathy: 2022 Update.

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.

ACR Appropriateness Criteria® Imaging of Facial Trauma Following Primary Survey.

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.

Imaging features of cartilaginous tumors of the head and neck.

There is a wide spectrum of head and neck cartilaginous lesions which include both neoplastic and nonneoplastic processes. Cartilaginous tumors of the head and neck are uncommon, posing a diagnostic challenge. Benign cartilaginous tumors that may occur in the head and neck include chondroma, chondroblastoma, chondromyxoid fibroma, osteochondroma, and synovial chondromatosis. Chondromesenchymal hamartoma is a rare non-neoplastic cartilaginous lesion that is included for the 1first time in the new WHO classification and radiologically can mimic a tumor. Malignant cartilaginous tumors include chondrosarcoma and chondroid variant of chordoma. Characteristic tumor locations, internal chondroid matrix calcification, and typical T2 hyperintense signal secondary to high-water content within the extracellular matrix of the hyaline cartilage are useful imaging features that narrow the differential diagnosis and help in diagnosing these diseases. This article presents a narrative review of the anatomy of the head and neck cartilaginous structures, discusses the current knowledge and imaging spectrum of benign and malignant cartilaginous tumors and tumor-like lesions of the head and neck.

Catastrophic Hemorrhage After Chemoradiation for Advanced Stage Oropharyngeal Carcinoma: A Case Series.

OBJECTIVES/HYPOTHESIS: We have seen several incidences of catastrophic bleeding in patients with advanced oropharyngeal squamous cell carcinoma treated nonoperatively. Aside from advanced disease, these patients have not had traditional risk factors for major hemorrhage. STUDY DESIGN: Retrospective chart review. METHODS: Patients treated nonoperatively for oropharyngeal squamous cell carcinoma were compared to determine characteristics that may predisposed to bleeding. Five patients with bleeding were identified and compared with a cohort of stage- and treatment-matched patients without bleeding. Blinded imaging review was performed to characterize the tumor site and its relationship to vasculature using standardized systems. RESULTS: Comparing the bleeder versus nonbleeder groups pre-treatment, the bleeder group had larger tumors (15.4 vs. 8.3 cm2 ), greater rates of parapharyngeal fat effacement (80% vs. 20%), and always involved the facial artery. Post-treatment, endophytic ulcerated tumor beds occurred in 100% of bleeders versus 0% of nonbleeders. CONCLUSIONS: Catastrophic oropharyngeal bleeding may be encountered after cytoreductive therapy. Large deeply invasive tumors seem to set the necessary circumstances. Rapid vascular control with interventional radiology has been largely effective therapy. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:1049-1052, 2021.

PET/CT Poorly Predicts AJCC 8th Edition Pathologic Staging in HPV-Related Oropharyngeal Cancer.

OBJECTIVE: The American Joint Committee on Cancer (AJCC) 8th edition introduced distinct clinical and pathological staging paradigms for human papilloma virus positive (HPV+) oropharyngeal squamous cell carcinoma (OPSCC). Treatment planning for OPSCC often utilizes positron emission tomography/computed tomography (PET/CT) to assess clinical stage. We hypothesize that PET/CT will accurately predict final pathologic AJCC 8th edition staging in patients with HPV+ OPSCC. METHODS: All patients with primary HPV+ OPSCC with preoperative PET/CT who underwent transoral robotic surgery and neck dissection between 2011 and 2017 were identified. Data were collected via chart review. Two neuroradiologists performed blinded re-evaluation of all scans. Primary tumor size and cervical nodal disease characteristics were recorded and TNM staging was extrapolated. Cohen's kappa statistic was used to assess interrater reliability. Test for symmetry was performed to analyze discordance between radiologic and pathologic staging. RESULTS: Forty-nine patients met inclusion criteria. Interrater reliability was substantial between radiologists for nodal (N) and overall staging (OS) (κ = 0.715 and 0.715). Radiologist A review resulted in identical OS for 67% of patients, overstaging for 31%, and understaging for 2%. Radiologist B review resulted in 61% identical OS, 39% overstaging, and 0% understaging. In misclassified cases, the test of symmetry shows strong bias toward overstaging N stage and OS (P < .001). Radiologic interpretation of extracapsular extension showed poor interrater reliability (κ = 0.403) and poor accuracy. CONCLUSION: PET/CT predicts a higher nodal and overall stage than pathologic staging. PET/CT should not be relied upon for initial tumor staging, as increased FDG uptake is not specific for nodal metastases. PET/CT is shown to be a poor predictor of ECE. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:1535-1541, 2021.

Interrater Reliability of NI-RADS on Posttreatment PET/Contrast-enhanced CT Scans in Head and Neck Squamous Cell Carcinoma.

Purpose To evaluate the interrater reliability among radiologists examining posttreatment head and neck squamous cell carcinoma (HNSCC) fluorodeoxyglucose PET/contrast-enhanced CT (CECT) scans using Neck Imaging Reporting and Data System (NI-RADS). Materials and Methods In this retrospective study, images in 80 patients with HNSCC who underwent posttreatment surveillance PET/CECT and immediate prior comparison CECT or PET/CECT (from June 2014 to July 2016) were uploaded to the American College of Radiology's cloud-based website, Cortex. Eight radiologists from seven institutions with variable NI-RADS experience independently evaluated each case and assigned an appropriate prose description and NI-RADS category for the primary site and the neck site. Five of these individuals were experienced readers (> 5 years of experience), and three were novices (< 5 years of experience). In total, 640 lexicon-based and NI-RADS categories were assigned to lesions among the 80 included patients by the eight radiologists. Light generalization of Cohen κ for interrater reliability was performed. Results Of the 80 included patients (mean age, 63 years ± 10 [standard deviation]), there were 58 men (73%); 60 patients had stage IV HNSCC (75%), and the most common tumor location was oropharynx (n = 32; 40%). Light κ for lexicon was 0.30 (95% CI: 0.23, 0.36) at the primary site and 0.31 (95% CI: 0.24, 0.37) at the neck site. Light κ for NI-RADS category was 0.55 (95% CI: 0.46, 0.63) at the primary site and 0.60 (95% CI: 0.48, 0.69) at the neck site. Percent agreement between lexicon and correlative NI-RADS category was 84.4% (540 of 640) at the primary site and 92.6% (593 of 640) at the neck site. There was no significant difference in interobserver agreement among the experienced versus novice raters. Conclusion Moderate agreement was achieved among eight radiologists using NI-RADS at posttreatment HNSCC surveillance imaging. Keywords: CT, PET/CT, Head/Neck, Neck, Neoplasms-Primary, Observer Performance Supplemental material is available for this article. © RSNA, 2021.

ACR Appropriateness Criteria® Parathyroid Adenoma.

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.