Characteristic MR Imaging Findings of Cerebral Air Embolism Infarcts: A Case Series.

Infarcts from cerebral air embolism (CAE) are rare events with potentially catastrophic clinical consequences. The imaging features of CAE are not well defined in the literature. We report a novel constellation of MR imaging findings of cerebral arterial air emboli induced infarcts in a series of 6 patients. Awareness of the more distinguishing MR-imaging patterns of CAE may help establish this diagnosis and facilitate implementation of timely treatment.ABBREVIATIONS: CAE = cerebral air embolism.

Performance of RAPID noncontrast CT stroke platform in large vessel occlusion and intracranial hemorrhage detection.

Background: Noncontrast CT (NCCT) is used to evaluate for intracerebral hemorrhage (ICH) and ischemia in acute ischemic stroke (AIS). Large vessel occlusions (LVOs) are a major cause of AIS, but challenging to detect on NCCT. Aims: The purpose of this study is to evaluate an AI software called RAPID NCCT Stroke (RAPID, iSchemaView, Menlo Park, CA) for ICH and LVO detection compared to expert readers. Methods: In this IRB approved retrospective, multicenter study, stand-alone performance of the software was assessed based on the consensus of 3 neuroradiologists and sensitivity and specificity were determined. The platform's performance was then compared to interpretation by readers comprised of eight general radiologists (GR) and three neuroradiologists (NR) in detecting ICH and hyperdense vessel sign (HVS) indicating LVO. Results: A total of 244 cases were included. Of the 244, 115 were LVOs and 26 were ICHs. One hundred three cases did not have LVO nor ICH. Stand-alone performance of the software demonstrated sensitivities and specificities of 96.2 and 99.5% for ICH and 63.5 and 95.1% for LVO detection. Compared to all 11 readers and eight GR readers only respectively, the software demonstrated superiority, achieving significantly higher sensitivities (63.5% versus 43.6%, p < 0.0001 and 63.5% versus 40.9%, p = 0.001). Conclusion: The RAPID NCCT Stroke platform demonstrates superior performance to radiologists for detecting LVO from a NCCT. Use of this software platform could lead to earlier LVO detection and expedited transfer of these patients to a thrombectomy capable center.

Temporal Characteristics of CSF-Venous Fistulas on Dynamic Decubitus CT Myelography: A Retrospective Multi-Institution Cohort Study.

BACKGROUND AND PURPOSE: CSF-venous fistula can be diagnosed with dynamic decubitus CT myelography. This study aimed to analyze the temporal characteristics of CSF-venous fistula visualization on multiphase decubitus CT myelography. MATERIALS AND METHODS: A retrospective, multisite study was conducted on patients diagnosed with CSF-venous fistula at 2 institutions between June 2017 and February 2023. Both institutions perform decubitus CT myelography with imaging immediately following injection and usually with at least 1 delayed scan. The conspicuity of CSF-venous fistula was assessed on each phase of imaging. RESULTS: Forty-eight patients with CSF-venous fistula were analyzed. CSF-venous fistulas were better visualized on the early pass in 25/48 cases (52.1%), the delayed pass in 6/48 cases (12.5%) and were seen equally on both passes in 15/48 cases (31.3%). Of 25 cases in which the CSF-venous fistula was better visualized on the early pass, 21/25 (84%) fistulas were still at least partially visible on a delayed pass. Of 6 cases in which the CSF-venous fistula was better visualized on a delayed pass, 4/6 (67%) were partially visible on the earlier pass. Six of 48 (12.5%) CSF-venous fistulas were visible only on a single pass. Of these, 4/6 (66.7%) were seen only on the first pass, and 2/6 (33.3%) were seen only on a delayed pass. One fistula was found with one pass only, and one fistula was discovered upon contralateral decubitus imaging without a dedicated second injection. CONCLUSIONS: A dynamic decubitus CT myelography imaging protocol that includes an early and delayed phase, likely increases the sensitivity for CSF-venous fistula detection. Further studies are needed to ascertain the optimal timing and technique for CSF-venous fistula visualization on dynamic decubitus CT myelography and its impact on patient outcomes.

Factors Predictive of Treatment Success in CT-Guided Fibrin Occlusion of CSF-Venous Fistulas: A Multicenter Retrospective Cross-Sectional Study.

BACKGROUND AND PURPOSE: CSF-to-venous fistulas contribute to spontaneous intracranial hypotension. CT-guided fibrin occlusion has been described as a minimally invasive treatment strategy; however, its reproducibility across different institutions remains unclear. This multi-institution study evaluated the clinical and radiologic outcomes of CT-guided fibrin occlusion, hypothesizing a correlation among cure rates, fibrin injectate spread, and drainage patterns. MATERIALS AND METHODS: A retrospective evaluation was conducted on CT-guided fibrin glue treatment in patients with CSF-to-venous fistulas from 6 US and UK institutions from 2020 to 2023. Patient information, procedural characteristics, and injectate spread and drainage patterns were examined. Clinical improvement assessed through medical records served as the primary outcome. RESULTS: Of 119 patients at a mean follow-up of 5.0 months, fibrin occlusion resulted in complete clinical improvement in 59.7%, partial improvement in 34.5%, and no improvement in 5.9% of patients. Complications were reported in 4% of cases. Significant associations were observed between clinical improvement and concordant injectate spread with the fistula drainage pattern (P = .0089) and pretreatment symptom duration (P < .001). No associations were found between clinical improvement and cyst puncture, intravascular extension, rebound headache, body mass index, age, or number of treatment attempts. CONCLUSIONS: Fibrin occlusion performed across various institutions shows cure when associated with injectate spread matching the CVF drainage pattern and shorter pretreatment symptom duration, emphasizing the importance of accurate injectate placement and early intervention.

Association of Incomplete Neurovascular Imaging After Emergency Department Encounters for Transient Ischemic Attack and Odds of Subsequent Stroke: A National Medicare Analysis.

BACKGROUND. Multisociety guidelines recommend urgent brain and neurovascular imaging for patients with transient ischemic attack (TIA), to identify and treat modifiable stroke risk factors. Prior research suggests that most patients with TIA who present to the emergency department (ED) do not receive prompt neurovascular imaging. OBJECTIVE. The purpose of this study was to evaluate the association between incomplete neurovascular imaging workup during ED encounters for TIA and the odds of subsequent stroke. METHODS. This retrospective study obtained data from the Medicare Standard Analytical Files for calendar years 2016 and 2017; these files contain 100% samples of claims for Medicare beneficiaries. Information was extracted using ICD 10th revision (ICD-10) and CPT codes. Those patients who were discharged from an ED encounter with a TIA diagnosis and who underwent brain CT or brain MRI during or within 2 days of the encounter were identified. Patients were considered to have complete neurovascular imaging if they underwent cross-sectional vascular imaging of both the brain (brain CTA or brain MRA) and neck (neck CTA, neck MRA, or carotid ultrasound) during or within 2 days of the encounter. The association between incomplete neurovascular imaging and a new stroke diagnosis within the subsequent 90 days was tested by multivariable logistic regression analysis. RESULTS. The sample included 111,417 patients (47,370 men, 64,047 women; 26.0% older than 84 years) who had TIA ED encounters. A total of 37.3% of patients (41,592) had an incomplete neurovascular imaging workup. A new stroke diagnosis within 90 days of the TIA ED encounter occurred in 4.4% (3040/69,825) of patients with complete neurovascular imaging versus 7.0% (2898/41,592) of patients with incomplete neurovascular imaging. Incomplete neurovascular imaging was associated with increased likelihood of stroke within 90 days (OR, 1.30 [95% CI, 1.23-1.38]) after adjustment for patient characteristics (age, sex, race and ethnicity, high-risk comorbidities, median county household income) and hospital characteristics (region, rurality, number of beds, major teaching hospital designation). CONCLUSION. TIA ED encounters with incomplete neurovascular imaging were associated with higher odds of subsequent stroke occurring within 90 days. CLINICAL IMPACT. Increased access to urgent neurovascular imaging for patients with TIA may represent a target that could facilitate detection and treatment of modifiable stroke risk factors.

Relationship of Bern Score, Spinal Elastance, and Opening Pressure in Patients With Spontaneous Intracranial Hypotension.

BACKGROUND AND OBJECTIVES: Existing tools to diagnose spontaneous intracranial hypotension (SIH), namely spinal opening pressure (OP) and brain MRI, have limited sensitivity. We investigated whether evaluation of brain MRI using the Bern score, combined with calculated craniospinal elastance, would aid in diagnosing SIH and provide insight into its pathophysiology. METHODS: A retrospective chart review was performed of patients who underwent brain MRI and pressure-augmented dynamic CT myelography (dCTM) for suspicion of SIH. Two blinded neuroradiologists assigned Bern scores for each brain MRI. OP and incremental pressure changes after intrathecal saline infusion were recorded to calculate craniospinal elastance. The relationship between Bern score, OP, and elastance and whether a leak was found were analyzed. RESULTS: Seventy-two consecutive dCTMs were performed in 53 patients. Twelve CSF-venous fistulae, 2 ruptured meningeal diverticula, 2 dural defects, and 1 dural bleb were found (17/53, 32%). Among patients with imaging-proven CSF leak/fistula, OP was normal in all but 1 patient and was not significantly different in those with a leak compared with those without (15.1 vs 13.6 cm H2O, p = 0.24, A = 0.40). The average Bern score in individuals with a leak was significantly higher than that in those without (5.35 vs 1.85, p < 0.001, A = 0.85), even when excluding pachymeningeal enhancement from the score (3.77 vs 1.57, p = 0.001, A = 0.78). The average elastance in those with a leak was higher than that in those without, but this difference was not statistically significant (2.05 vs 1.20 mL/cm H2O, p = 0.19, A = 0.40). Increased elastance was significantly associated with an increased Bern score (95% CI -0.55 to 0.12, p < 0.01) and was significantly associated with venous distention, pachymeningeal enhancement, prepontine narrowing, and subdural collections, but not a narrowed mamillopontine or suprasellar distance. DISCUSSION: OP is not an effective predictor for diagnosing CSF leak and if used in isolation would result in misdiagnosis of 94% of patients in our cohort. The Bern score was associated with a higher diagnostic yield of dCTM. Elastance was significantly associated with certain components of the Bern score.

Structured Reporting for Findings of Spontaneous Intracranial Hypotension on Brain MRI.

A voluntary structured reporting template (based on the Bern score) for brain MRI examinations performed for suspected spontaneous intracranial hypotension (SIH) was associated with an increase in reporting of intracranial MRI findings of SIH and a reduction in discordant assessments with respect to a reference reader.

Ordering Characteristics Predictive of Noncontrast CT Head Positivity in the Emergency Department.

RATIONALE AND OBJECTIVES: Recent decades have seen a steady increase in noncontrast head CT utilization in the emergency department with a concurrent rise in the practice of physician assistants (PAs) and nurse practitioners (NPs). The goal of this study was to identify ordering and patient characteristics predictive of positive noncontrast head CTs in the ED. We hypothesized NP/PAs would have lower positivity rates compared to physicians, suggestive of relative overutilization. MATERIALS AND METHODS: We retrospectively identified ED patients who underwent noncontrast head CTs at a single institution: a nonlevel 1 trauma center, during a 7-year period, recording examination positivity, ordering provider training/experience, and multiple additional ordering/patient attributes. Exam positivity was defined as any intracranial abnormality necessitating a change in acute management, such as acute hemorrhage, hydrocephalus, herniation, or worsening prior findings. RESULTS: 6624 patients met inclusion criteria. 4.6% (280/6107) of physician exams were positive while 3.7% (19/517) of NP/PA exams were positive; however, differences were not significant. Increasing provider experience was not associated with positivity. Attributes with increased positivity were patient age (p < 0.001), daytime exam (p < 0.05), and indications regarding malignancy (p < 0.001) or focal neurologic deficit (p = 0.001). Attributes with decreased positivity were indications of trauma (p < 0.001) or vertigo/dizziness (p < 0.05). CONCLUSION: We found no significant difference in rates of exam positivity between physicians and NP/PAs, even accounting for years of experience. This suggests increasing utilization of head CTs in the ED is not due to the increasing presence of NP/PAs, and may be reflective of general practice trends and clear diagnostic algorithms leading to head CT.

Evaluation of Cerebrovascular Reactivity and Vessel Wall Imaging in Patients With Prior COVID-19: A Prospective Case-Control MRI Study.

BACKGROUND. SARS-CoV-2 infection is associated with acute stroke, possibly caused by viral tropism to the vascular endothelium. Whether cerebrovascular endothelial dysfunction and inflammation persist after acute infection is poorly understood. OBJECTIVE. The purposes of this study were to assess the association between prior SARS-CoV-2 infection and cerebrovascular reactivity (CVR) and vessel wall imaging (VWI) abnormalities and to explore the association between CVR impairment and post-COVID neurologic conditions. METHODS. This prospective study included 15 participants with prior SARS-CoV-2 infection (11 women, four men; mean age, 43 years; mean time since infection, 238 days; three with prior critical illness, 12 with prior mild illness; seven with post-COVID neurologic conditions) and 10 control participants who had never had SARS-CoV-2 infection (two women, two men; mean age, 44 years) from July 1, 2021, to February 9, 2022. Participants underwent research MRI that included arterial spin labeling perfusion imaging with acetazolamide stimulus to measure cerebral blood flow (CBF) and calculate CVR. Examinations also included VWI, performed with a contrast-enhanced black-blood 3D T1-weighted sequence. An age- and sex-adjusted linear model was used to assess associations between CVR and prior infection. A t test was used to assess associations between CVR and post-COVID neurologic conditions in participants with previous infection. A difference of proportions test was used to assess associations between VWI abnormalities and infection status. RESULTS. Mean whole-cortex CBF after acetazolamide administration was greater in participants without previous infection than in participants with previous infection (73.8 ± 13.2 [SD] vs 60.5 ± 15.8 mL/100 gm/min; p = .04). Whole-brain CVR was lower in participants with previous infection than those without previous infection (difference, -8.9 mL/100 g/min; p < .001); significantly lower CVR was also observed in participants with previous infection after exclusion of those with prior critical illness. Among participants with previous infection, CVR was lower in those with than those without post-COVID neurologic conditions, although this difference was not significant (16.9 vs 21.0 mL/100 g/min; p = .22). Six of 15 (40%) participants with previous infection versus 1 of 10 (10%) participants without previous infection had at least one VWI abnormality (p = .18). All VWI abnormalities were consistent with atherosclerosis. CONCLUSION. SARS-CoV-2 infection is associated with chronic impairment of CVR. The mechanism is unknown from this study. CLINICAL IMPACT. Future studies are needed to determine the clinical implications of SARS-CoV-2-associated CVR impairment.

A Practical Guide to Use of Publicly Available Data Sets for Observational Research in Interventional Radiology.

Observational data research studying access, utilization, cost, and outcomes of image-guided interventions using publicly available "big data" sets is growing in the interventional radiology (IR) literature. Publicly available data sets offer insight into real-world care and represent an important pillar of IR research moving forward. They offer insights into how IR procedures are being used nationally and whether they are working as intended. On the other hand, large data sources are aggregated using complex sampling frames, and their strengths and weaknesses only become apparent after extensive use. Unintentional misuse of large data sets can result in misleading or sometimes erroneous conclusions. This review introduces the most commonly used databases relevant to IR research, highlights their strengths and limitations, and provides recommendations for use. In addition, it summarizes methodologic best practices pertinent to all data sets for planning and executing scientifically rigorous and clinically relevant observational research.

RAPID Aneurysm: Artificial intelligence for unruptured cerebral aneurysm detection on CT angiography.

OBJECTIVES: Cerebral aneurysms may result in significant morbidity and mortality. Identification of these aneurysms on CT Angiography (CTA) studies is critical to guide patient treatment. Artificial intelligence platforms to assist with automated aneurysm detection are of high interest. We determined the performance of a semi-automated artificial intelligence software program (RAPID Aneurysm) for the detection of cerebral aneurysms. MATERIALS AND METHODS: RAPID Aneurysm was used to detect retrospectively the presence of cerebral aneurysms in CTA studies performed between January 2019 and December 2020. The gold standard was aneurysm presence and location as determined by the consensus of three expert neuroradiologists. Aneurysm detection accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and positive and negative likelihood ratios by RAPID Aneurysm were determined. RESULTS: 51 patients (mean age, 56±15; 24 women [47.1%]) with a single CTA were included. A total of 60 aneurysms were identified. RAPID Aneurysm had a sensitivity of 0.950 (95% CI: 0.863-0.983), specificity of 1.000 (95% CI: 0.996-1.000), a positive predictive value (PPV) of 1.000 (95% CI: 0.937-1.000), a negative predictive value (NPV) of 0.997 (95% CI: 0.991-0.999), and an accuracy of 0.997 (95% CI: 0.991-0.999) for cerebral aneurysm detection. CONCLUSIONS: RAPID Aneurysm is highly accurate for the detection of cerebral aneurysms on CTA.

Lost to Follow-Up: A Nationwide Analysis of Patients With Transient Ischemic Attack Discharged From Emergency Departments With Incomplete Imaging.

PURPOSE: Imaging guidelines for transient ischemic attack (TIA) recommend that patients undergo urgent brain and neurovascular imaging within 48 hours of symptom onset. Prior research suggests that most patients with TIA discharged from the emergency department (ED) do not complete recommended TIA imaging workup during their ED encounters. The purpose of this study was to determine the nationwide percentage of patients with TIA discharged from EDs with incomplete imaging workup who complete recommended imaging after discharge. METHODS: Patients discharged from EDs with the diagnosis of TIA were identified from the Medicare 5% sample for 2017 and 2018 using International Classification of Diseases, tenth rev, Clinical Modification codes. Imaging performed was identified using Current Procedural Terminology codes. Incomplete imaging workup was defined as a TIA encounter without cross-sectional brain, brain-vascular, and neck-vascular imaging performed within the subsequent 30 days of the initial ED encounter. Patient- and hospital-level factors associated with incomplete TIA imaging were analyzed in a multivariable logistic regression. RESULTS: In total, 6,346 consecutive TIA encounters were analyzed; 3,804 patients (59.9%) had complete TIA imaging workup during their ED encounters. Of the 2,542 patients discharged from EDs with incomplete imaging, 761 (29.9%) completed imaging during the subsequent 30 days after ED discharge. Among patients with TIA imaging workup completed after ED discharge, the median time to completion was 5 days. For patients discharged from EDs with incomplete imaging, the odds of incomplete TIA imaging at 30 days after discharge were highest for black (odds ratio, 1.84; 95% confidence interval, 1.27-2.66) and older (≥85 years of age; odds ratio, 2.41; 95% confidence interval, 1.78-3.26) patients. Reference values were age cohort 65 to 69 years; male gender; white race; no co-occurring diagnoses of hypertension, hyperlipidemia, or diabetes mellitus; household income > $63,029; hospital in the Northeast region; urban hospital location; hospital size > 400 beds; academically affiliated hospital; and facility with access to MRI. CONCLUSIONS: Most patients discharged from EDs with incomplete TIA imaging workup do not complete recommended imaging within 30 days after discharge.

Algorithmic Multimodality Approach to Diagnosis and Treatment of Spinal CSF Leak and Venous Fistula in Patients With Spontaneous Intracranial Hypotension.

Spontaneous intracranial hypotension (SIH) is a disorder of CSF dynamics that causes a complex clinical syndrome and severe disability. SIH is challenging to diagnose because of the variability of its presenting clinical symptoms, the potential for subtle imaging findings to be easily overlooked, and the need for specialized diagnostic testing. Once SIH is suggested by clinical history and/or supported by initial neuroim-aging, many patients may undergo initial nontargeted epidural blood patching with variable and indefinite benefit. However, data suggest that precise localization of the CSF leak or CSF-venous fistula (CVF) can lead to more effective and durable treatment strategies. Leak localization can be achieved using a variety of advanced diagnostic imaging techniques, although these may not be widely performed at nontertiary medical centers, leaving many patients with the potential for inadequate workup or treatment. This review describes imaging techniques including dynamic fluoroscopic and CT myelography as well as delayed MR myelography and treatment options including percutaneous, endovascular, and surgical approaches for SIH. These are summarized by an algorithmic framework for radiologists to approach the workup and treatment of patients with suspected SIH. The importance of a multidisciplinary approach is emphasized.

Intracranial meningioma surveillance using volumetrics from T2-weighted MRI.

BACKGROUND AND PURPOSE: The gold standard for imaging of meningiomas is MRI with gadolinium-based contrast agent. Due to increased costs, time, and uncertain chronic effects of gadolinium exposure, use of noncontrast T2-weighted imaging (T2WI) in lieu of contrast-enhanced MRI has been an increasing focus of research across various diagnostic scenarios. The purpose of this study was to evaluate the diagnostic accuracy of T2WI in detecting changes in meningioma tumor volume. METHODS: Imaging and clinical data were reviewed for 82 consecutive patients undergoing MR-surveillance of intracranial meningioma. Using volumetric-T2WI, two neuroradiologists independently calculated tumor volumes. Measurements were compared to a baseline study contrast-enhanced T1 tumor volume. Using contrast-enhanced sequences as the reference standard, statistical analysis was performed to determine the accuracy of T2WI in detecting changes of meningioma volume. RESULTS: Using only T2WI, readers detected meningioma volume change ≥ 20% in 19/82 patients and volume change <20% in 63/82 patients. Reader accuracy for detecting change in tumor volume on T2WI ≥ 20% was 0.85, sensitivity 0.65, specificity 0.93, positive predictive value (PPV) 0.79, and negative predictive value (NPV) 0.87. For meningiomas >1 ml, reader accuracy for detecting change in tumor volume on T2WI ≥20% was 0.90, sensitivity 0.78, specificity 0.95, PPV 0.88, and NPV 0.91. Change in tumor volume on T2WI ≥20% was detected with 100% accuracy for posterior fossa meningiomas. Inter-reader agreement for all meningiomas was moderate (κ = 0.45) improving to substantial agreement (κ = 0.77) with tumor volumes >1 ml. CONCLUSION: Volumetric-T2WI detects changes in meningioma volume with comparable accuracy to gold standard T1 postcontrast imaging, particularly with higher tumor volumes and posterior fossa locations.

ACR Appropriateness Criteria® Low Back Pain: 2021 Update.

In the United States, acute low back pain, with or without radiculopathy, is the leading cause of years lived with disability and the third ranking cause of disability-adjusted life-years. Uncomplicated acute low back pain and/or radiculopathy is a benign, self-limited condition that does not warrant any imaging studies. Imaging is considered in those patients who have had up to 6 weeks of medical management and physical therapy that resulted in little or no improvement in their back pain. It is also considered for those patients presenting with red flags, raising suspicion for a serious underlying condition, such as cauda equina syndrome, malignancy, fracture, or infection. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Plexopathy: 2021 Update.

Plexopathy may be caused by diverse pathologies, including trauma, nerve entrapment, neoplasm, inflammation, infection, autoimmune disease, hereditary disease, and idiopathic etiologies. For patients presenting with brachial or lumbosacral plexopathy, dedicated plexus MRI is the most appropriate initial imaging modality for all clinical scenarios and can identify processes both intrinsic and extrinsic to the nerves. Other imaging tests may be appropriate for initial imaging depending on the clinical scenario. This document addresses initial imaging strategies for brachial and lumbosacral plexopathy in the following clinical situations: nontraumatic plexopathy with no known malignancy, traumatic plexopathy (not perinatal), and plexopathy occurring in the context of a known malignancy or posttreatment syndrome. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Suspected Spine Infection.

Spine infection is both a clinical and diagnostic imaging challenge due to its relatively indolent and nonspecific clinical presentation. The diagnosis of spine infection is based upon a combination of clinical suspicion, imaging evaluation and, when possible, microbiologic confirmation performed from blood cultures or image-guided percutaneous or open spine biopsy. With respect to the imaging evaluation of suspected spine infection, MRI without and with contrast of the affected spine segment is the initial diagnostic test of choice. As noncontrast MRI of the spine is often used in the evaluation of back or neck pain not responding to conservative medical management, it may show findings that are suggestive of infection, hence this procedure may also be considered in the evaluation of suspected spine infection. Nuclear medicine studies, including skeletal scintigraphy, gallium scan, and FDG-PET/CT, may be helpful in equivocal or select cases. Similarly, radiography and CT may be appropriate for assessing overall spinal stability, spine alignment, osseous integrity and, when present, the status of spine instrumentation or spine implants. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Redundant Imaging in Transient Ischemic Attack: Evidence From the Nationwide Emergency Department Sample.

PURPOSE: Increasing emergency department (ED) compliance with transient ischemic attack (TIA) imaging guidelines has previously been demonstrated, along with a substantial rise in imaging utilization over the past decade. The purpose of this study was to characterize the most commonly used combinations of imaging studies during ED workup of TIA and to quantify prevalence of redundant imaging (RI). METHODS: TIA discharges from EDs in the United States from 2006 to 2017 were identified in the Nationwide Emergency Department Sample. Brain and neurovascular imaging obtained during the encounter was identified using Current Procedural Terminology codes. RI was defined as an ED encounter with any duplicate cross-sectional brain, brain-vascular, or neck-vascular imaging. Patient demographics and hospital characteristics were incorporated into a multivariable logistic regression analysis to identify significant associations with RI. RESULTS: There were 184,870 discharges with TIA from EDs in 2017. RI (brain) was observed in 55,513 (30%) of encounters. RI (brain-vascular) and RI (neck-vascular) imaging was identified in 5,149 (2.8%) and 1,325 (0.7%) of encounters, respectively. Decreased odds of obtaining RI was observed in Medicaid patients (odds ratio [OR]: 0.72, 95% confidence interval [CI]: 0.64-0.81), non-trauma centers (OR: 0.49, 95% CI: 0.26-0.93), rural hospital locations (OR: 0.18, 95% CI: 0.11-0.29), and weekend encounters (OR: 0.9, 95% CI: 0.85-0.96). Trend analysis from 2006 to 2017 demonstrated a rise in RI (brain) from 2.3% of encounters in 2006 to 30% of encounters in 2017. RI for patients discharged from EDs with TIA in 2017 resulted in additional charges of approximately US$8,670,832. CONCLUSION: Increased imaging utilization for TIA workup across EDs in the United States is associated with rising use of redundant imaging. We identify imaging practices that could be targeted to mitigate health care expenditures while adhering to TIA imaging guidelines.