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Background and ObjectivesTo assess the accuracy of baseline CT perfusion (CTP) ischemic core estimates.MethodsFrom SELECT (Optimizing Patient Selection for Endovascular Treatment in Acute Ischemic Stroke), a prospective multicenter cohort study of imaging selection, patients undergoing endovascular thrombectomy who achieved complete reperfusion (modified Thrombolysis In Cerebral Ischemia score 3) and had follow-up diffusion-weighted imaging (DWI) available were evaluated. Follow-up DWI lesions were coregistered to baseline CTP. The difference between baseline CTP core (relative cerebral blood flow [rCBF] <30%) volume and follow-up infarct volume was classified as overestimation (core ≥10 mL larger than infarct), adequate, or underestimation (core ≥25 mL smaller than infarct) and spatial overlap was evaluated.ResultsOf 101 included patients, median time from last known well (LKW) to imaging acquisition was 138 (82–244) minutes. The median baseline ischemic core estimate was 9 (0–31.9) mL and median follow-up infarct volume was 18.4 (5.3–68.7) mL. All 6/101 (6%) patients with overestimation of the subsequent infarct volume were imaged within 90 minutes of LKW and achieved rapid reperfusion (within 120 minutes of CTP). Using rCBF <20% threshold to estimate ischemic core in patients presenting within 90 minutes eliminated overestimation. Volumetric correlation between the ischemic core estimate and follow-up imaging improved as LKW time to imaging acquisition increased: Spearman ρ <90 minutes 0.33 (p = 0.049), 90–270 minutes 0.63 (p < 0.0001), >270 minutes 0.86 (p < 0.0001). Assessment of the spatial overlap between baseline CTP ischemic core lesion and follow-up infarct demonstrated that a median of 3.2 (0.0–9.0) mL of estimated core fell outside the subsequent infarct. These regions were predominantly in white matter.DiscussionSignificant overestimation of irreversibly injured ischemic core volume was rare, was only observed in patients who presented within 90 minutes of LKW and achieved reperfusion within 120 minutes of CTP acquisition, and occurred primarily in white matter. Use of a more conservative (rCBF <20%) threshold for estimating ischemic core in patients presenting within 90 minutes eliminated all significant overestimation cases.Trial Registration InformationClinicalTrials.gov: NCT03876457.

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Background: Extranodal extension (ENE) is an important adverse prognostic factor in oropharyngeal cancer (OPC) and is often employed in therapeutic decision making. Clinician-based determination of ENE from radiological imaging is a difficult task with high inter-observer variability. However, the role of clinical specialty on the determination of ENE has been unexplored. Methods: Pre-therapy computed tomography (CT) images for 24 human papillomavirus-positive (HPV+) OPC patients were selected for the analysis; 6 scans were randomly chosen to be duplicated, resulting in a total of 30 scans of which 21 had pathologically-confirmed ENE. 34 expert clinician annotators, comprised of 11 radiologists, 12 surgeons, and 11 radiation oncologists separately evaluated the 30 CT scans for ENE and noted the presence or absence of specific radiographic criteria and confidence in their prediction. Discriminative performance was measured using accuracy, sensitivity, specificity, area under the receiver operating characteristic curve (AUC), and Brier score for each physician. Statistical comparisons of discriminative performance were calculated using Mann Whitney U tests. Significant radiographic factors in correct discrimination of ENE status were determined through a logistic regression analysis. Interobserver agreement was measured using Fleiss kappa. Results: The median accuracy for ENE discrimination across all specialties was 0.57. There were significant differences between radiologists and surgeons for Brier score (0.33 vs. 0.26), radiation oncologists and surgeons for sensitivity (0.48 vs. 0.69), and radiation oncologists and radiologists/surgeons for specificity (0.89 vs. 0.56). There were no significant differences between specialties for accuracy or AUC. Indistinct capsular contour, nodal necrosis, and nodal matting were significant factors in regression analysis. Fleiss kappa was less than 0.6 for all the radiographic criteria, regardless of specialty. Conclusions: Detection of ENE in HPV+OPC patients on CT imaging remains a difficult task with high variability, regardless of clinician specialty. Although some differences do exist between the specialists, they are often minimal. Further research in automated analysis of ENE from radiographic images is likely needed.

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Seizures have been reported in association with idiopathic intracranial hypertension in pediatric patients. Magnetic resonance imaging (MRI) signs of intracranial hypertension have not been investigated before in pediatric patients with new-onset idiopathic seizures. MRI scans of 182 pediatric patients were retrospectively analyzed for imaging findings of intracranial hypertension, including 46 patients with new-onset idiopathic seizures and elevated cerebrospinal fluid opening pressure, 40 patients with new-onset idiopathic seizures and normal opening pressure, 56 patients with confirmed idiopathic intracranial hypertension, and 40 age- and sex-matched controls. The optic nerve sheath diameter is significantly larger in the group with new-onset idiopathic seizures and elevated opening pressure (mean diameter of 6.02 ± 0.45 mm) compared to patients with new-onset idiopathic seizures and normal opening pressure (mean diameter of 5.24 ± 0.50 mm) ( P value <.001). The cutoff value of 6.0 mm for optic nerve sheath diameter showed 63% sensitivity and 88% specificity to differentiate pediatric patients with seizures and elevated opening pressure from those with seizures and normal opening pressure. Conclusion A cutoff value of 6.0 mm for optic nerve sheath dilation may be used as a screening imaging marker to suspect elevated opening pressure with specificity of 88% in pediatric patients with new-onset idiopathic seizures.