Stem cell induced inflammatory hypertrophy of the cauda equina.

Stem cell therapy can present clinicians with challenging clinical scenarios, as access to such treatments outpaces the research into their efficacy and safety due to the burgeoning trend of international travel to acquire stem cell therapy, or "stem cell tourism." Treatment of neurologic conditions remains an enticing potential application of stem cell therapy, often administered intrathecally. In response to such therapy, multiple adverse events have been described in the literature, including neoplasms, demyelinating disease, and seizures, among others. We present a case of symptomatic inflammatory cauda equina nerve root hypertrophy due to intrathecal stem cell infusion, representing a rare but significant complication.

Implementation of emergent MRI for wake-up stroke: a single-center experience.

PURPOSE: Recent updates in national guidelines for management of acute ischemic stroke in patients of unknown time of symptom onset ("wake-up" strokes) incorporate, for the first time, use of emergent MRI. In this retrospective case series, we analyze our experience at a Comprehensive Stroke Center implementing a new workflow including MRI in this clinical setting. This study also describes "DWI-FLAIR" mismatch, a critical concept for the interpretation of emergent brain MRIs performed for wake-up strokes. METHODS: Over a 14-month period, all brain MRIs for wake-up stroke were identified. The imaging was analyzed by two board-certified, fellowship-trained neuroradiologists, and a diagnosis of DWI-FLAIR mismatch was made by consensus. Process metrics assessed included interval between last known well time and brain imaging, interval between CT and MRI, and interval between brain MRI and interpretation. RESULTS: Sixteen patients with a history of "wake-up stroke" were identified. Thirteen of the 16 patients (81.3%) were found to have a DWI-FLAIR mismatch, suggesting infarct < 4.5 h old. The mean time between last known well and MRI was 7.89 h with mean interval between CT and MRI of 1.83 h. Forty-six percent of patients with DWI-FLAIR mismatch received intravenous thrombolysis. CONCLUSION: In this "real world" assessment of incorporation of emergent MRI for wake-up strokes, there were several key factors to successful implementation of this new workflow, including effective and accurate description of MRI findings; close collaboration amongst stakeholders; 24/7 availability of MRI; and 24/7 onsite coverage by neurology and radiology physicians.

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.

Chapter 1 Neck Anatomy, Imaging-Based Level Nodal Classification and Impact of Primary Tumor Site on Patterns of Nodal Metastasis.

The anatomy of the neck is complex, with many critical structures crowded together in a relatively small cross-sectional area. Many structures in the neck also have similar soft tissue density or signal that further complicates interpretation for the radiologist, who relies on tissue differences to create contrast resolution and distinguish structures. Head and neck cancer incidence exceeds 550,000 cases per year worldwide, with diagnosis, treatment, and prognosis relying highly on a thorough knowledge of this compact space. This article focuses on reviewing head and neck anatomy with special attention to nodal anatomy and on discussing the expected patterns of nodal spread in head and neck cancers.