Diagnostic accuracy of NI-RADS for prediction of head and neck squamous cell carcinoma: a systematic review and meta-analysis.

OBJECTIVES: This study aimed to assess the diagnostic performance of NI-RADS for the prediction of recurrence in patients treated for Head and Neck Squamous Cell Carcinoma (HNSCC). METHODS: A literature search was conducted using various databases to identify relevant articles published from June 2016 onwards. We included studies reporting the diagnostic accuracy of NI-RADS in distinguishing recurrence in patients undergoing imaging surveillance, with pathologic results and/or follow-up as the reference standard. Summary estimates of diagnostic accuracy in terms of sensitivity, specificity, positive likelihood ratio (LR +), negative likelihood ratio (LR -), and diagnostic odds ratio (DOR) were calculated with the hierarchical summary receiver operating characteristic (HSROC) model. Meta-regression and subgroup analyses were conducted to investigate different clinical settings. Study quality was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. RESULTS: A total of 12 studies were included in the current meta-analysis. The pooled sensitivity and specificity were 0.69 (95% CI 0.59-0.79) and 0.94 (95% CI 0.89-0.97), respectively. For the primary site, the pooled summary estimates were 0.67 (95% CI 0.53-0.78) and 0.95 (95% CI 0.90-0.97), for the nodal sites were 0.64 (95% CI 0.44-0.80) and 0.99 (95% CI 0.98-0.99), respectively. The recurrence rate for NI-RADS categories 1-3 was 0.03 (95% CI 0.02-0.05), 0.13 (95% CI 0.10-0.15), and 0.77 (95% CI 0.73-0.81). Meta-regression revealed that the type of analysis (per person vs. per site) and number of sites (≤ 200 vs. > 200) were significant factors associated with heterogeneity. CONCLUSIONS: NI-RADS demonstrated high specificity but moderate sensitivity in patients after treatment for HNSCC. Summary estimates showed a significantly higher malignancy rate for NI-RADS category 3 compared to category 2.

Response assessment of post-treatment head and neck cancers to determine further management using NI-RADS (Neck Imaging Reporting and Data System): a subgroup analysis of a randomized controlled trial.

Objective: Interpreting complex post-treatment changes in head and neck cancer (HNC) is challenging with further added perplexity due to variable interobserver interpretation and hence evolved the NI-RADS lexicon. We evaluated the accuracy of NI-RADS in predicting disease status on 1st post-treatment follow-up CECT in a homogenous cohort of those who received only chemoradiation. Methods: Retrospective analysis of imaging was done for LASHNC patients who received radical chemoradiation in an open-label, investigator-initiated, phase 3 randomized trial (2012-2018) randomly assigned to either radical radiotherapy with concurrent weekly cisplatin (CRT) or CRT with the same schedule plus weekly nimotuzumab (NCRT). 536 patients were accrued, and 74 patients who did not undergo PET/CECT after 8 weeks post-CRT were excluded. After assessing 462 patients for eligibility to allocate NI-RADS at primary and node sites, 435 cases fell in the Primary disease cohort and 412 cases in the Node disease cohort. We evaluated sensitivity, disease prevalence, the positive and negative predictive value of the NI-RADS lexicon, and accuracy, which were expressed as percentages. We also prepared flow charts to determine concordance with allocated NI-RADS category and established accuracy with which it can identify disease status. Results: Out of 435 primary disease cohort, 92%, 55%, 48%,70% were concordant and had 100%, 72%, 70%, 82% accuracy in NI-RADS1 (n=12), NI-RADS2 (n=261), NIRADS3 (n=105), and NI-RADS 4 (n=60) respectively. Out of 412 nodes disease cohort, 95%, 90%, 48%, 70%were concordant and had 92%, 97%, 90%, 67% accuracy in NI-RADS1 (n=57), NI-RADS2 (n=255), NI-RADS3 (n=105) and NI-RADS4 (n=60) respectively. % concordance of PET/CT and CECT across all primary and node disease cohorts revealed that PET/CT was 91% concordant in primary NI-RADS2 as compared to 55% concordance of CECT whereas concordance of CECT was better with 57% in primary NI-RADS3 cohort as compared to PET/CT concordance of 41%. Conclusion: The accuracy with which the NI-RADS lexicon performed in our study at node sites was better than that at the primary site. There is a great scope of research to understand if CECT performs better over clinical disease status in NI-RADS 3 and 4 categories. Further research should be carried out to understand if PET/CECT can be used for close interval follow-up in stage III/IV NI-RADS 2 cases.

Imaging of Neck Nodes in Head and Neck Cancers - a Comprehensive Update.

Cervical lymph node metastases from head and neck squamous cell cancers significantly reduce disease-free survival and worsen overall prognosis and, hence, deserve more aggressive management and follow-up. As per the eighth edition of the American Joint Committee on Cancer staging manual, extranodal extension, especially in human papillomavirus-negative cancers, has been incorporated in staging as it is important in deciding management and significantly impacts the outcome of head and neck squamous cell cancer. Lymph node imaging with various radiological modalities, including ultrasound, computed tomography and magnetic resonance imaging, has been widely used, not only to demonstrate nodal involvement but also for guided histopathological evaluation and therapeutic intervention. Computed tomography and magnetic resonance imaging, together with positron emission tomography, are used widely for the follow-up of treated patients. Finally, there is an emerging role for artificial intelligence in neck node imaging that has shown promising results, increasing the accuracy of detection of nodal involvement, especially normal-appearing nodes. The aim of this review is to provide a comprehensive overview of the diagnosis and management of involved neck nodes with a focus on sentinel node anatomy, pathogenesis, imaging correlates (including radiogenomics and artificial intelligence) and the role of image-guided interventions.

Diagnostic Performance of Response Assessment FDG-PET/CECT in HNSCC Treated With Definitive Radio(chemo)therapy Using NI-RADS.

OBJECTIVE: To assess the diagnostic performance of response assessment 18F-fluorodeoxyglucose positron emission tomography/contrast-enhanced computed tomography (FDG-PET/CECT) following definitive radio(chemo)therapy in head and neck squamous cell carcinoma (HNSCC) using Neck Imaging Reporting and Data System (NI-RADS). STUDY DESIGN: A retrospective analysis from a prospectively maintained dataset. SETTING: Tertiary-care comprehensive cancer center in a low-middle-income country. METHODS: Adults with newly diagnosed, biopsy-proven, nonmetastatic HNSCC treated with definitive radio(chemo)therapy were included. Posttreatment response assessment FDG-PET/CECT scans were retrospectively assigned NI-RADS categories (1-3) for the primary site, neck, and both sites combined. Locoregional recurrence occurring within 2-years was defined as the event of interest. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy were calculated. Locoregional control stratified by NI-RADS categories was computed with the Kaplan-Meier method and compared using the log-rank test. RESULTS: Posttreatment FDG-PET/CECT scans were available in 190 patients constituting the present study cohort. Sensitivity, specificity, PPV, NPV, and overall accuracy of the NI-RADS template for the primary site was 73.5%, 81.4%, 46.3%, 93.4%, and 80.0%, respectively. Similar metrics for the neck were 72.7%, 87.5%, 43.2%, 96.1%, and 85.8%, respectively. Combining primary site and neck, the corresponding metrics of diagnostic accuracy were 84.4%, 69.7%, 46.3%, 93.5%, and 73.2%, respectively. At a median follow-up of 40 months, Kaplan-Meier estimates of 2-year locoregional control were significantly higher for NI-RADS category 1 (94.2%) compared to NI-RADS category 2 (69.4%) and category 3 (20.4%), respectively (stratified log-rank p < .0001). CONCLUSION: FDG-PET/CECT using the NI-RADS template is associated with good diagnostic performance and prognostic utility in HNSCC treated with definitive radio(chemo)therapy.

Performance of the Neck Imaging Reporting and Data System as applied by general neuroradiologists to predict recurrence of head and neck cancers.

BACKGROUND: The Neck Imaging Reporting and Data System (NI-RADS) is used to assess imaging after head and neck cancer treatment. We evaluated NI-RADS with general neuroradiologists rather than with head and neck subspecialists. METHODS: Computed tomography and magnetic resonance imaging examinations with/without positron emission tomography from May 2018 to September 2020 were retrospectively identified. NI-RADS scores at the primary site and lymph nodes were provided by 21 neuroradiologists. Recurrence status was based on clinical and imaging findings. Area under the curve (AUC) was used to assess accuracy. RESULTS: We assessed 608 scans from 464 patients. For NI-RADS categories 1, 2, and 3, primary site recurrence rates were 5%, 29%, and 65% with AUC of 0.765, while lymph node recurrence rates were 3%, 10%, and 80% with AUC of 0.820. CONCLUSIONS: NI-RADS as used by general neuroradiologists is effective in separating head and neck cancers into discrete categories for predicting recurrent disease.

NI-RADS to Predict Residual or Recurrent Head and Neck Squamous Cell Carcinoma.

American College of Radiology NI-RADS is a surveillance imaging template used to predict residual or recurrent tumor in the setting of head and neck cancer. The lexicon and imaging template provides a framework to standardize the interpretations and communications with referring physicians and provides linked management recommendations, which add value in patient care. Studies have shown reasonable interreader agreement and excellent discriminatory power among the different NI-RADS categories. This article reviews the literature associated with NI-RADS and serves as a practical guide for radiologists interested in using the NI-RADS surveillance template at their institution, highlighting frequently encountered pearls and pitfalls.

Lymph Node Dissection: Principles and Postoperative Imaging.

The management of neck nodes in head and neck cancer is critical, given a markedly increased poor prognosis in patients with nodal metastasis. The surgical management of neck nodes has undergone radical changes secondary to a paradigm shift from curative surgery to nonsurgical organ and function-preserving options, such as radiation therapy. In the neck after treatment, radiologists should be familiar with imaging findings in various types of neck dissections and post-chemoradiation changes, along with signs of residual or recurrent disease. A multidisciplinary approach is essential with well-designed evidence-based surveillance imaging protocols and standardized reporting.

Impact of double reading on NI-RADS diagnostic accuracy in reporting oral squamous cell carcinoma surveillance imaging - a single-center study.

OBJECTIVES: The Neck Imaging Reporting and Data System (NI-RADS) is an increasingly utilized risk stratification tool for imaging surveillance after treatment for head and neck cancer. This study aims to measure the impact of supervision by subspecialized radiologists on diagnostic accuracy of NI-RADS when initial reading is performed by residents. METHODS: 150 CT and MRI datasets were initially read by two trained residents, and then supervised by two subspecialized radiologists. Recurrence rates by NI-RADS category were calculated, and receiver operating characteristic (ROC) curves were plotted. After dichotomization of the NI-RADS system (category 1 vs categories 2 + 3+4 and categories 1 + 2 vs 3 + 4), sensitivity, specificity, positive and negative predictive value were calculated. RESULTS: 26% of the reports were modified by the supervising radiologists. Area under the curve of ROC plots values of the supervision session were higher than those of the initial reading session for both the primary site (0.89 vs 0.86) and the neck (0.94 vs 0.91), but the difference was not statistically significant. For dichotomized NI-RADS category assignments, differences between the initial reading and the supervision session were statistically significant regarding specificity and PPV for the primary site (1 + 2 vs 3 + 4 and 1 vs 2 + 3+4) or even for both sites combined (1 vs 2 + 3+4). CONCLUSION: NI-RADS enables trained resident radiologists to report surveillance imaging in patients with treated oral squamous cell carcinoma with high discriminatory power. Additional supervision by a subspecialized head and neck radiologist particularly improves specificity of radiological reports.

Best Practices: Application of NI-RADS for Posttreatment Surveillance Imaging of Head and Neck Cancer.

Imaging surveillance is an important component of posttreatment management of head and neck cancers. There is variability in the surveillance regimen used by various practitioners and institutions, with no official National Comprehensive Cancer Network guidelines for patients showing no symptoms beyond 6 months posttreatment. Moreover, imaging of the neck after treatment is a complex examination with significant interreader heterogeneity, particularly in terms of the manner in which degree of suspicion for disease recurrence is expressed. The Neck Imaging Reporting and Data System (NI-RADS) was introduced by the American College of Radiology (ACR) in 2018 as a practical guide for the interpreting radiologist. NI-RADS is a proposed interpretive framework that can be applied to any standardized or institutional surveillance imaging protocol. NI-RADS simplifies communication between radiologists and referring clinicians and provides management guidance linked to specific levels of suspicion. The ACR NI-RADS Committee also provided general best practice recommendations for imaging surveillance modality and timing in the 2018 white paper. This article will review existing literature regarding choice of modality and timeline for surveillance in treated cancer of the head and neck. NI-RADS will then be presented as an approach to imaging reporting, interpretation, and design of next steps in management.

Retrospective Evaluation of NI-RADS for Detecting Postsurgical Recurrence of Oral Squamous Cell Carcinoma on Surveillance CT or MRI.

BACKGROUND. Imaging surveillance is important for the early diagnosis of recurrence after definitive treatment of oral squamous cell carcinoma (OSCC). The Neck Imaging Reporting and Data System (NI-RADS) includes a standardized template for surveillance imaging and categorizes probability of recurrence at the primary site and in the neck (cervical lymph nodes) by assigning categories of 1 (no evidence of recurrence), 2 (low suspicion, subdivided into 2a and 2b for the primary site), 3 (high suspicion), and 4 (definite recurrence). OBJECTIVE. The aim of this study was to determine the rate of locoregional and nodal OSCC recurrence stratified by NI-RADS category among patients undergoing surveillance CT or MRI. METHODS. This retrospective study included 158 patients enrolled in an institutional surveillance program after resection of OSCC with curative intent. A total of 503 contrast-enhanced CT or MRI examinations performed during surveillance were evaluated. Each examination was randomly assigned to one of four radiologists with expertise in head and neck imaging, who provided NI-RADS categories for the primary site and the neck (1006 assigned NI-RADS categories). NI-RADS performance in identifying recurrence was assessed by ROC curve analysis. All four readers evaluated 50 randomly assigned cases to determine interreader agreement by use of the Kendall W statistic. RESULTS. Cancer recurrence was confirmed in 7.6% (38/503) of cases for the primary site and in 6.2% (31/503) for the neck. For the primary site, recurrence rates were 1.0% in NI-RADS category 1, 7.1% in category 2a, 5.6% in category 2b, 66.7% in category 3, and 100.0% in category 4. For the neck, recurrence rates were 0.5% in category 1, 7.0% in category 2, 80.0% in category 3, and 100.0% in category 4. NI-RADS had AUC values of 0.934 for the primary site and 0.959 for the neck. Interreader agreement was 0.67 for the primary site and 0.81 for the neck. CONCLUSION. NI-RADS offers excellent discriminatory power in detection of OSCC recurrence, both for the primary site and the neck. CLINICAL IMPACT. Radiologists and maxillofacial surgeons should implement NI-RADS in surveillance regimens for postoperative OSCC to help detect recurrences in an effective and standardized manner using imaging.

Interreader reproducibility of the Neck Imaging Reporting and Data system (NI-RADS) lexicon for the detection of residual/recurrent disease in treated head and neck squamous cell carcinoma (HNSCC).

BACKGROUND: To evaluate the inter- and intrareader agreement and reproducibility of the NI-RADS scoring system and lexicon with contrast-enhanced computed tomography (CECT) and contrast-enhanced magnetic resonance imaging (CEMRI). METHODS: This retrospective study included 97 CECT and CEMRI scans from 58 treated cases of head and neck squamous cell carcinoma (HNSCC) after the exclusion of head and neck cancers (HNCs) other than SCC and noncontrast and poor quality CT and MRI scans, with a total of 111 primary targets and 124 lymph node (LN) targets. Two experienced readers independently scored the likelihood of residual/recurrence for these targets based on the NI-RADS criteria and filled in report templates for NI-RADS lexicon diagnostic features. Inter- and intraobserver reproducibility was assessed with Cohen's kappa, and the percent agreement was calculated. RESULTS: Almost perfect interreader agreement was found for the final NI-RADS category of the primary lesions and LNs, with K = 0.808 and 0.806, respectively. Better agreement was found for CT than for MRI (K = 0.843 and 0.77, respectively, P value 0.001). There was almost perfect agreement for excluding tissue enhancement (K = 0.826, 95% CI = 0.658-0.993, P value 0.001), with a percent agreement of 96.4%, and substantial agreement for discrete nodular and diffuse mucosal enhancement (K = 0.826, 95% CI = 0.658-0.993, P value 0.001), with a percent agreement of 96.4%. There was fair agreement for focal mucosal nonmass and deep ill-defined enhancement. The intrareader agreement was almost perfect for most of the rated features (K ranging from 0.802 to 1), with the exception of enlarging discrete nodule/mass and focal mucosal nonmass-like enhancement, which had substantial intraobserver agreement (K ranging from 0.768 to 0.786). CONCLUSION: The individual features of NI-RADS show variable degrees of confidence; however, the overall NI-RADS category was not significantly affected.

Neck Imaging Reporting and Data System: Principles and Implementation.

Head and neck cancer surveillance imaging is diagnostically challenging, often with highly distorted anatomy after surgery and chemoradiation therapy. In the era of standardized reporting, the Neck Imaging Reporting and Data System (NI-RADS) was developed as a numerical classification system to provide clear and concise radiology reports and recommend next management step. There are 5 categories, each conveying a certain level of suspicion for the presence of persistent or recurrent disease. This article reviews the goals of NI-RADS, NI-RADS categories and lexicon, current research, and the future direction of NI-RADS in posttreatment head and neck cancer surveillance.

NI-RADS for head and neck cancer surveillance imaging: What, why, and how.

The Neck Imaging Reporting and Data System (NI-RADS) was conceived in 2016 with the objective of standardizing assessment and reporting in surveillance imaging for patients with head and neck squamous cell carcinomas and their subsequent management. The goals are to simplify radiology reports while increasing the consistency and accuracy of the interpretation of cancer surveillance imaging; enable better communication among clinicians and between clinicians and patients; facilitate outcomes research; and ultimately improve patient survival, morbidity, and mortality. The objective of the current study was to provide the background as to why and how NI-RADS was conceived and what it entails in radiology reporting.

ACR Neck Imaging Reporting and Data Systems (NI-RADS): A White Paper of the ACR NI-RADS Committee.

Imaging surveillance after treatment for head and neck cancer is challenging because of complicated resection and reconstruction surgery, in addition to posttreatment changes from radiation and chemotherapy. The posttreatment neck is often a source of anxiety for diagnostic radiologists, leading to suboptimal reporting and no standardized guidance for next management steps. Nevertheless, imaging is critical for detecting submucosal recurrences in a timely manner, so that patients remain candidates for salvage surgery. In 2016, the ACR convened the Neck Imaging Reporting and Data Systems (NI-RADS) Committee with the goals to (1) provide recommendations for surveillance imaging; (2) produce a lexicon to distinguish between benign posttreatment change and residual or recurrent tumor in the posttreatment neck; and (3) propose a NI-RADS template for reporting on the basis of this lexicon with defined levels of suspicion and management recommendations. In this article, the authors present the ACR NI-RADS Committee's recommendations, which provide guidance regarding the management of patients after treatment for head and neck cancer.

Neck Imaging Reporting and Data System.

The Neck Imaging Reporting and Data System (NI-RADS) is a practical and clinically useful imaging surveillance template designed to guide appropriate imaging follow-up and next-management steps. This article is a practical guide for using NI-RADS to reduce report-generation time for radiologists and create useful reports for referring clinicians and patients. A review of the report template and legend is followed by a case-based and pictorial review of the proper assignment of NI-RADS categories.