Liebo, Greta B.

Epidural steroid injections are commonly performed using fluoroscopic or CT guidance. With both modalities, the injection of contrast material is necessary before steroid administration to ensure adequate epidural flow and exclude non-epidural flow. While fluoroscopic guidance is conventional, CT is utilized at some centers and can be particularly helpful in the setting of challenging or postoperative anatomy. It is important for proceduralists to be adept at evaluating contrast media flow patterns under both modalities. The goal of this review article is to describe and provide examples of epidural and non-epidural flow patterns on both conventional fluoroscopy and CT. Specific non-epidural patterns discussed include intrathecal flow, intradural/subdural flow, vascular uptake, flow into the retrodural space of Okada, inadvertent facet joint flow, and intradiscal flow.

Introduction Spontaneous intracranial hypotension (SIH) caused by a spinal cerebrospinal fluid (CSF) leak classically presents with orthostatic headache. Digital subtraction myelography (DSM) has a well-established diagnostic yield in the absence of extradural spinal collection. At our institution, DSM is followed by lateral decubitus CT myelogram (LDCTM) in the same decubitus position to increase diagnostic yield of the combined study. We evaluated the incremental diagnostic yield of LDCTM following negative DSM and reviewed patient outcomes. Methods Retrospective review of consecutive DSMs with subsequent LDCTM from April 2019 to March 2021 was performed. Combined reports were reviewed, and studies with positive DSMs were excluded. Of the exams with negative DSM, only studies with LDCTM reports identifying potential leak site were included. Interventions and follow-up clinical notes were reviewed to assess symptoms improvement following treatment. Results Of the 83 patients with negative DSMs, 11 (13.2%) had positive leak findings on LDCTMs, and 21 (25.3%) were equivocal. Of 11 positive LDCTMs, 6 leaks were nerve sheath tears (NSTs) and 5 were CSF-venous fistulas (CVFs). 10/11 (90.9%) had intervention and follow-up, with 9/10 (90%) having positive clinical outcome. Of the 21 equivocal LDCTM patients (19 CVFs and 2 NSTs), 15 (71.4%) had interventions and follow-up, with 3/15 (20.0%) with positive clinical outcomes. Conclusion LDCTM following negative DSM has an incremental diagnostic yield up to 38.6%, with up to 14.5% of positive patient outcomes following treatment. LDCTM should be considered after DSM to maximize diagnostic yield of the combined exam.

Introduction There is increased interest in the use of artificial intelligence-based (AI) software packages in the evaluation of neuroimaging studies for acute ischemic stroke. We studied whether, compared to standard image interpretation without AI, Brainomix e-ASPECTS software improved interobserver agreement and accuracy in detecting ASPECTS regions affected in anterior circulation LVO. Methods We included 60 consecutive patients with anterior circulation LVO who had TICI 3 revascularization within 60 minutes of their baseline CT. A total of 16 readers, including senior neuroradiologists, junior neuroradiologists and vascular neurologists participated. Readers interpreted CT scans on independent workstations and assessed final ASPECTS and evaluated whether each individual ASPECTS region was affected. Two months later, readers again evaluated the CT scans, but with assistance of e-ASPECTS software. We assessed interclass correlation coefficient for total ASPECTS and interobserver agreement with Fleiss’ Kappa for each ASPECTS region with and without assistance of the e-ASPECTS. We also assessed accuracy for the readers with and without e-ASPECTS assistance. In our assessment of accuracy, ground truth was the 24 hour CT in this cohort of patients who had prompt and complete revascularization. Results Interclass correlation coefficient for total ASPECTS without e-ASPECTS assistance was 0.395, indicating fair agreement compared, to 0.574 with e-ASPECTS assistance, indicating good agreement (P < 0.01). There was significant improvement in inter-rater agreement with e-ASPECTS assistance for each individual region with the exception of M6 and caudate. The e-ASPECTS software had higher accuracy than the overall cohort of readers (with and without e-ASPECTS assistance) for every region except the caudate. Conclusions Use of Brainomix e-ASPECTS software resulted in significant improvements in inter-rater agreement and accuracy of ASPECTS score evaluation in a large group of neuroradiologists and neurologists. e-ASPECTS software was more predictive of final infarct/ASPECTS than the overall group interpreting the CT scans with and without e-ASPECTS assistance.

Purpose Understanding all factors that may impact radiation dose and procedural time is crucial to safe and efficient image-guided interventions, such as fluoroscopically guided sacroiliac (SI) joint injections. The purpose of this study was to evaluate the effect of flow pattern (intra- vs. periarticular), patient age, and body mass index (BMI) on radiation dose and fluoroscopy time. Methods A total of 134 SI joint injections were reviewed. Injectate flow pattern, age, and BMI were analyzed in respect to fluoroscopy time (minutes), radiation dose (kerma area product (KAP); µGy m 2 ), and estimated skin dose (mGy). Results BMI did not affect fluoroscopy time, but increased BMI resulted in significantly higher skin and fluoroscopy doses ( p < 0.001). There was no association between fluoroscopy time and flow pattern. Higher skin dose was associated with intraarticular flow ( p = 0.0086), and higher KAP was associated with periarticular flow ( p = 0.0128). However, the odds ratios were close to 1. There was no significant difference between fluoroscopy time or dose based on patient age. Conclusion Increased BMI had the largest impact on procedural radiation dose and skin dose. Flow pattern also showed a statistically significant association with radiation dose and skin dose, but the clinical difference was small. Proceduralists should be aware that BMI has the greatest impact on fluoroscopy dose and skin dose during SI joint injections compared to other factors.

Autoimmune epilepsy (AE) is becoming increasingly recognized as a potentially reversible cause of frequent or medically intractable seizures and cognitive deterioration. We describe various presentations of autoimmune encephalopathy which have specifically presented with seizure and describe reported imaging findings. This is organized as a review of the more common autoantibodies which can specifically precipitate seizure according to the intracellular or extracellular location of the targeted antigen. For each antibody, we illustrate their pathophysiology, characteristic clinical presentations with typical effective treatments and prognoses and imaging findings on MRI and PET/CT exams. Parenchymal involvement is variable with the limbic structures typically affected; however, non-limbic cortex, cerebellum, brainstem and basal ganglia can also be involved. In the acute setting, affected regions typically demonstrate T 2 hyperintensity with mild mass effect from edema and increased 18F-fludeoxyglucose uptake. Chronically involved parenchyma will often undergo atrophy and demonstrate decreased metabolism; mesial temporal sclerosis is often the end result when the limbic system is involved. Without treatment, long-term effects from AE range from ongoing cognitive dysfunction and refractory seizures to death. Familiarity with AE may prompt appropriate antibody screening, particularly in cases of refractory seizure disorders. Early investigation and proper management of AE cases may help to prevent parenchymal and neurologic deterioration in these patients.

Purpose The relationship between syringomyelia and presyrinx, characterized by edema in the spinal cord, has not been firmly established. Patients with syringomyelia have abnormal spinal canal tapering that alters cerebrospinal fluid flow dynamics, but taper ratios in presyrinx have never been reported. We tested the hypothesis that presyrinx patients have abnormal spinal canal tapering. Materials and methods At six medical institutions, investigators searched the PACS system for patients with Chiari I and spinal cord edema unassociated with tumor, trauma, or other evident cause. In each case taper ratios were calculated for C1 to C4 and C4 to C7. In two age- and gender-matched control groups, Chiari I patients with no syringomyelia and patients with normal MR scans, the same measurements were made. Differences between groups were tested for statistical significance with t tests. Results The study enrolled 21 presyrinx patients and equal numbers of matched Chiari I and normal controls. C4 to C7 taper ratios were positive and steeper in presyrinx patients than in the normal controls ( p = 0.04). The upper cervical spine, C1 to C4, tapered negatively in cases and controls without significant differences between the groups. The difference in degree of tonsillar herniation was statistically significant between presyrinx patients and Chiari I controls ( p = 0.01). Conclusions Presyrinx patients have greater than normal positive tapering in the lower cervical spine and greater degree of tonsillar herniation than the controls.