Traumatic spondylolisthesis of axis: clinical and imaging experience at a level one trauma center.

PURPOSE: Traumatic spondylolisthesis of the axis (TSA) with bilateral pars interarticularis fracture (a pattern also known as Hangman's fractures) accounts for 4-5% of all cervical fractures. Various classification systems have been described to assist therapeutic decision-making. The goal is to reassess the utility of these classifications for treatment strategy and evaluate additional imaging associations. METHODS: This is an IRB approved, retrospective analysis of patients with imaging diagnosis of TSA from 2016 to 2019. Consensus reads were performed classifying TSA into various Levine and Edwards subtypes and typical vs. atypical fractures. Other imaging findings such as additional cervical fractures, traumatic brain injury, spinal cord injury, and vertebral artery injury were recorded. Treatment strategy and outcome were reviewed from clinical charts. Fisher exact test was used for statistical analysis. RESULTS: A total of 58 patients were included, with a mean age of 62.7 ± 25 years, and male to female ratio of 1:1.2. Motor vehicle collision was the most common cause of TSA. Type I and III injuries were the most and the least common injuries, respectively. Patients with type I injuries were found to have good healing rates with conservative management (p < 0.001) while type IIa and III injuries were managed with surgical stabilization (p = 0.04 and p = 0.01, respectively). No statistical difference was observed in the treatment strategy for type II fractures (p = 0.12) and its prediction of the associated injuries. Atypical fractures were not found to have a higher incidence of SCI (p = 0.31). A further analysis revealed significantly higher-grade vertebral artery injuries (grades III and IV according to Biffl grading) in patients with type IIa and III injuries (p = 0.001) and an 11-fold increased risk of TBI compared to type I and type II fractures (p = 0.013). CONCLUSION: TSA fracture types were not associated with any clinical outcome. Levine and Edwards type II classification itself is not enough to guide the treatment plan and does not account for associated injuries. Additional imaging markers may be needed.

Accuracy of CT Perfusion-Based Core Estimation of Follow-up Infarction: Effects of Time Since Last Known Well.

BACKGROUND AND OBJECTIVES: To assess the accuracy of baseline CT perfusion (CTP) ischemic core estimates. METHODS: From 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. RESULTS: Of 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. DISCUSSION: Significant 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 INFORMATION: ClinicalTrials.gov: NCT03876457.

Neuroimaging Features of Intracranial Hypertension in Pediatric Patients With New-Onset Idiopathic Seizures, a Comparison With Patients with Confirmed Diagnosis of Idiopathic Intracranial Hypertension: A Preliminary Study.

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.

Leveraging Spatial Information in Radiology Reports for Ischemic Stroke Phenotyping.

Classifying fine-grained ischemic stroke phenotypes relies on identifying important clinical information. Radiology reports provide relevant information with context to determine such phenotype information. We focus on stroke phenotypes with location-specific information: brain region affected, laterality, stroke stage, and lacunarity. We use an existing fine-grained spatial information extraction system-Rad-SpatialNet-to identify clinically important information and apply simple domain rules on the extracted information to classify phenotypes. The performance of our proposed approach is promising (recall of 89.62% for classifying brain region and 74.11% for classifying brain region, side, and stroke stage together). Our work demonstrates that an information extraction system based on a fine-grained schema can be utilized to determine complex phenotypes with the inclusion of simple domain rules. These phenotypes have the potential to facilitate stroke research focusing on post-stroke outcome and treatment planning based on the stroke location.

Heparin for Vertebral Intraluminal Thrombus Causing Retroperitoneal Hemorrhage from Occult Renal Angiomyolipoma.

Stroke is a common cause of mortality and serious long-term disability worldwide. In the acute setting, current American Heart Association/American Stroke Association guidelines do not recommend routine anticoagulation for the management of acute ischemic strokes. However, short-term use of unfractionated heparin (UFH) in select subpopulations has demonstrated improved outcomes. While tools such as CHADSVASC and HASBLED scores are useful in stratifying risk of long-term anticoagulation in patients with nonvalvular atrial fibrillation and additional risk factors, the carefully selected patient populations for the design of these studies do not account for risk of hemorrhage from other preexisting conditions. Here, we present a patient with a posterior circulation intraluminal thrombus treated with UFH, who manifested with a near-fatal intra-abdominal hemorrhage from a previously undetected renal angiomyolipoma (AML).

Atlanto-occipital distraction injuries in survivors: craniometrics and associated ligamentous, spinal cord, and blunt cerebrovascular injury.

PURPOSE: Newer classification systems for upper cervical spine trauma now include ligamentous injury in addition to fracture and dislocation patterns. Assessment of associated ligamentous injury, spinal cord injury (SCI), and blunt cerebrovascular injuries (BCVI) in patients with atlanto-occipital distraction injuries (AODI) are critical for management. We aim to determine the incidence of ligamentous injury, SCI, and BCVI in patients with AODI and assess how craniometrics perform in diagnosis of AODI. MATERIALS AND METHODS: We performed an IRB-approved retrospective analysis of 35 cases of diagnosed AODI over a period of 8 years. Imaging was analyzed by two experienced neuroradiologists for craniometric measurements, ligamentous injury, SCI, and BCVI. Craniometric measurements were compared to 35 age-matched controls with normal atlanto-occipital joint. RESULTS: Out of 35 patients diagnosed with AODI, 27 were adults and 8 belonged to pediatric age group. The mean age of presentation was 29.4 years with a male/female ratio of 22:13. The basion-dental interval (70.4%) and the combined condylar sum (74.1%) were the most sensitive craniometric measurements for diagnosis of AODI. Alar ligament (83%) and the tectorial membrane (89%) injuries were most commonly injured ligaments. Three adult patients sustained SCI and 10 patients had BCVI. Majority of BCVI involved the internal carotid artery followed by the vertebral artery. CONCLUSIONS: The combination of craniometric indices with assessment of ligamentous injuries provides higher diagnostic accuracy for AODI. Alar ligament and tectorial membrane injuries have high association with AODI. There is high association of SCI and BCVI in AODI survivors.

Risk Analysis and Management of Third Ventricular Colloid Cysts.

OBJECTIVE: Colloid cysts (CCs) are histologically benign lesions that carry the risk of causing obstructive hydrocephalus. The indication for surgery for symptomatic cysts is unquestioned; however, the management of incidentally detected lesions has remained controversial. We independently evaluated the CC risk score (CCRS) as a useful risk stratification scheme. METHODS: The demographics, imaging characteristics, and clinical presentations of 103 patients with CC during a 10-year period were correlated with symptoms and the occurrence of hydrocephalus. The discriminate capacity of the CCRS was quantified and a decision algorithm formulated. RESULTS: The correlates of symptoms included age <65 years, diameter ≥7 mm, anterior location, hyperintensity on T2-weighted fluid-attenuated inversion recovery (FLAIR) and/or T2-weighted images, and headache at presentation without an alternative explanation. On multivariate analysis, age <65 years, diameter ≥7 mm, and headache at presentation predicted for symptomatic cysts. The CCRS was highly effective at identifying symptomatic patients and those with obstructive hydrocephalus. All patients with cyst growth and symptomatic progression had had an initial CCRS of ≥3 plus hyperintensity (preexisting or developing) on T2-weighted FLAIR images. CONCLUSIONS: The CCRS performed exceptionally well in distinguishing the highest risk patients. Closer follow-up is recommended for younger asymptomatic patients with cysts near the foramen of Monro. Hyperintensity on T2-weighted FLAIR images might indicate greater growth potential for small lesions.

Rad-SpatialNet: A Frame-based Resource for Fine-Grained Spatial Relations in Radiology Reports.

This paper proposes a representation framework for encoding spatial language in radiology based on frame semantics. The framework is adopted from the existing SpatialNet representation in the general domain with the aim to generate more accurate representations of spatial language used by radiologists. We describe Rad-SpatialNet in detail along with illustrating the importance of incorporating domain knowledge in understanding the varied linguistic expressions involved in different radiological spatial relations. This work also constructs a corpus of 400 radiology reports of three examination types (chest X-rays, brain MRIs, and babygrams) annotated with fine-grained contextual information according to this schema. Spatial trigger expressions and elements corresponding to a spatial frame are annotated. We apply BERT-based models (BERTBASE and BERTLARGE) to first extract the trigger terms (lexical units for a spatial frame) and then to identify the related frame elements. The results of BERTLARGE are decent, with F1 of 77.89 for spatial trigger extraction and an overall F1 of 81.61 and 66.25 across all frame elements using gold and predicted spatial triggers respectively. This frame-based resource can be used to develop and evaluate more advanced natural language processing (NLP) methods for extracting fine-grained spatial information from radiology text in the future.

Incidence of cervical spine fractures on CT: a study in a large level I trauma center.

INTRODUCTION/PURPOSE: Though spinal fractures constitute a minority of all traumas, the financial burden imposed is immense especially following cervical spine trauma. There have been several papers in the past describing the incidence of cervical spine fractures. In this paper, we report the incidence of cervical spine fractures and correlate with demographic information and cause of injury and review the mechanism of fractures. MATERIALS AND METHODS: We performed retrospective analysis of 934 patients who had undergone CT scan for cervical spine trauma at our institute which includes 16 hospitals and one level I trauma center over a period of 2 years. This list was created from a wider database of 13,512 patients imaged for suspected cervical spine injury. All patients who had at least one positive finding on CT were included in this study irrespective of any demographic difference. Each patient was analyzed by reviewing the medical records, and correlation was sought between demographics and cause of injury. RESULTS: In our study, the peak incidence of cervical spine trauma was in the age group of 21-30 years followed by 31-40 years with a male:female ratio of 2.1. The major cause of injury in the study population was motor vehicle accidents (66.1%), followed by fall from height of less than 8 ft (12.2%). With regard to the ethnic distribution, Caucasians (46.9%) constituted the major population followed by Hispanic population (23.3%). C1 and C2 were observed to be more frequently fractured as compared with the subaxial spine. Incidence of C2 fractures (188 levels) was higher as compared with C1 (102 levels). Incidence of body and lateral mass fractures was marginally higher as compared with odontoid fractures. C7 (50 levels) was the most fractured vertebral body in the subaxial spine followed by C6 (35 levels) and C5. CONCLUSION: Spinal trauma is on the rise and it helps to know the factors which can guide us for better management of these patients. We can utilize these results to prognosticate and streamline clinical management of these patients.