CT for Treatment Selection in Acute Ischemic Stroke: A Code Stroke Primer.

CT is the primary imaging modality used for selecting appropriate treatment in patients with acute stroke. Awareness of the typical findings, pearls, and pitfalls of CT image interpretation is therefore critical for radiologists, stroke neurologists, and emergency department providers to make accurate and timely decisions regarding both (a) immediate treatment with intravenous tissue plasminogen activator up to 4.5 hours after a stroke at primary stroke centers and (b) transfer of patients with large-vessel occlusion (LVO) at CT angiography to comprehensive stroke centers for endovascular thrombectomy (EVT) up to 24 hours after a stroke. Since the DAWN and DEFUSE 3 trials demonstrated the efficacy of EVT up to 24 hours after last seen well, CT angiography has become the operational standard for rapid accurate identification of intracranial LVO. A systematic approach to CT angiographic image interpretation is necessary and useful for rapid triage, and understanding common stroke syndromes can help speed vessel evaluation. Moreover, when diffusion-weighted MRI is unavailable, multiphase CT angiography of collateral vessels and source-image assessment or perfusion CT can be used to help estimate core infarct volume. Both have the potential to allow distinction of patients likely to benefit from EVT from those unlikely to benefit. This article reviews CT-based workup of ischemic stroke for making tPA and EVT treatment decisions and focuses on practical skills, interpretation challenges, mimics, and pitfalls.©RSNA, 2019.

Prehospital Triage of Acute Ischemic Stroke Patients to an Intravenous tPA-Ready versus Endovascular-Ready Hospital: A Decision Analysis.

BACKGROUND: American Stroke Association guidelines for prehospital acute ischemic stroke recommend against bypassing an intravenous tPA-ready hospital (IRH), if additional transportation time to an endovascular-ready hospital (ERH) exceeds 15-20 min. However, it is unknown when the benefit of potential endovascular therapy at an ERH outweighs the harm from delaying intravenous therapy at a closer IRH, especially since large vessel occlusion (LVO) status is initially unknown. We hypothesized that current time recommendations for IRH bypass are too short to achieve optimal outcomes for certain patient populations. METHODS: A decision analysis model was constructed using population-based databases, a detailed literature review, and interventional trial data containing time-dependent modified Rankin Scale distributions. The base case was triaged by Emergency Medical Services (EMS) 110 min after stroke onset and had a 23.6% LVO rate. Base case triage choices were (1) transport to the closest IRH (12 min), (2) transport to the ERH (60 min) bypassing the IRH, or (3) apply the Cincinnati Stroke Triage Assessment Tool and transport to the ERH if positive for LVO. Outcomes were assessed using quality-adjusted life years (QALYs). Sensitivity analyses were performed for all major variables, and alternative prehospital stroke scales were assessed. RESULTS: In the base case, transport to the IRH was the optimal choice with an expected outcome of 8.47 QALYs. Sensitivity analyses demonstrated that transport to the ERH was superior until bypass time exceeded 44 additional minutes, or when the onset to EMS triage interval exceeded 99 min. As the probability of LVO increased, ERH transport was optimal at longer onset to EMS triage intervals. The optimal triage strategy was highly dependent on specific interactions between the IRH transportation time, ERH transportation time, and onset to EMS triage interval. CONCLUSIONS: No single time difference between IRH and ERH transportation optimizes triage for all patients. Allowable IRH bypass time should be increased and acute ischemic stroke guidelines should incorporate the onset to EMS triage interval, IRH transportation time, and ERH transportation time.

Time to angiographic reperfusion in acute ischemic stroke: decision analysis.

BACKGROUND AND PURPOSE: Our objective was to use decision analytic modeling to compare 2 treatment strategies of intravenous recombinant tissue-type plasminogen activator (r-tPA) alone versus combined intravenous r-tPA/endovascular therapy in a subgroup of patients with large vessel (internal carotid artery terminus, M1, and M2) occlusion based on varying times to angiographic reperfusion and varying rates of reperfusion. METHODS: We developed a decision model using Interventional Management of Stroke (IMS) III trial data and comprehensive literature review. We performed 1-way sensitivity analyses for time to reperfusion and 2-way sensitivity for time to reperfusion and rate of reperfusion success. We also performed probabilistic sensitivity analyses to address uncertainty in total time to reperfusion for the endovascular approach. RESULTS: In the base case, endovascular approach yielded a higher expected utility (6.38 quality-adjusted life years) than the intravenous-only arm (5.42 quality-adjusted life years). One-way sensitivity analyses demonstrated superiority of endovascular treatment to intravenous-only arm unless time to reperfusion exceeded 347 minutes. Two-way sensitivity analysis demonstrated that endovascular treatment was preferred when probability of reperfusion is high and time to reperfusion is small. Probabilistic sensitivity results demonstrated an average gain for endovascular therapy of 0.76 quality-adjusted life years (SD 0.82) compared with the intravenous-only approach. CONCLUSIONS: In our post hoc model with its underlying limitations, endovascular therapy after intravenous r-tPA is the preferred treatment as compared with intravenous r-tPA alone. However, if time to reperfusion exceeds 347 minutes, intravenous r-tPA alone is the recommended strategy. This warrants validation in a randomized, prospective trial among patients with large vessel occlusions.

Hypofractionated stereotactic radiotherapy for unifocal and multifocal recurrence of malignant gliomas.

To evaluate the efficacy and safety of stereotactic radiotherapy (SRT) for unifocal and multifocal recurrence of malignant gliomas. Between June 2007 and October 2010, 35 consecutive patients with 47 recurrent lesions were treated with salvage SRT at the University of Cincinnati. Thirty-three patients treated had a diagnosis of high grade glioma, four Grade III and twenty-nine Grade IV, while two patients initially were diagnosed with grade II tumors but recurred as high grade lesions. All patients had previously received a median dose of 59.4 Gy. Twenty-six patients were treated for a single lesion, and nine patients were treated for multiple lesions. Using SRT, patients were re-treated with a median total dose of 30 Gy in a median of five fractions. Median survival from diagnosis was 22 months and median survival following SRT was 8.6 months. The median survival following SRT for those patients treated for multifocal recurrence was 7.9 versus 10 months for those treated for unifocal recurrence (p = 0.7). Multivariate analysis showed local control of the SRT treated lesion(s) 6 months after SRT was associated with a significant improvement in survival (p ≤ 0.01). All patients tolerated their treatment well and completed their prescribed SRT as planned. Three patients (9 %) were felt to possibly have developed radiation necrosis following therapy. SRT was both well tolerated and efficacious with the local control provided by SRT resulting in improved overall survival. This benefit also seems to be apparent for patients with multi-focal recurrence.

Imaging of Headache Attributed to Vascular Disorders.

Imaging is essential in the diagnosis of vascular causes of headaches. With advances in technology, there are increasing options of imaging modalities to choose from, each with its own advantages and disadvantages. This article will focus on imaging pearls and pitfalls of vascular causes of headaches. These include aneurysms, vasculitides, vascular malformations, and cerebral venous thrombosis.

Put your back into it: pathologic conditions of the spine at chest CT.

It is common to encounter pathologic processes of the lower cervical, thoracic, or upper lumbar spine in the course of routine computed tomography (CT) of the chest. Although magnetic resonance (MR) is the imaging modality of choice for evaluating known spinal disease, evaluation of the spine is an integral part of interpreting a chest CT study. Spinal diseases often have a characteristic CT appearance that allows the radiologist to make the diagnosis or provide a structured differential diagnosis. Pathologic conditions of the spine that can be identified at chest CT are categorized into benign or incidental findings, congenital anomalies, traumatic injuries, infectious spondylitis, primary or secondary neoplastic involvement, and associations with systemic disease. CT also provides information about bone mineralization and lesion calcification that complements the superior soft-tissue imaging capability of MR. In addition, chest CT data may be reformatted to create volumetric or multiplanar images of the spine to facilitate management decisions about spinal stabilization in symptomatic patients.

Reducing the gray zone: imaging spectrum of hypoperfusion and hypoxic brain injury in adults.

The purpose of this pictorial essay is to illustrate the computed tomography and magnetic resonance imaging manifestations of hypoperfusion and hypoxic brain injury in adults, a clinical scenario not uncommon in the emergency room setting. The imaging findings can be subtle or marked depending on the type of injury and the time elapsed from injury to imaging. Accurate recognition of the imaging findings in hypoperfusion and hypoxic injury in adults is important for accurate therapy and family-patient counseling.

Phenotype-Agnostic Molecular Subtyping of Neurodegenerative Disorders: The Cincinnati Cohort Biomarker Program (CCBP).

Ongoing biomarker development programs have been designed to identify serologic or imaging signatures of clinico-pathologic entities, assuming distinct biological boundaries between them. Identified putative biomarkers have exhibited large variability and inconsistency between cohorts, and remain inadequate for selecting suitable recipients for potential disease-modifying interventions. We launched the Cincinnati Cohort Biomarker Program (CCBP) as a population-based, phenotype-agnostic longitudinal study. While patients affected by a wide range of neurodegenerative disorders will be deeply phenotyped using clinical, imaging, and mobile health technologies, analyses will not be anchored on phenotypic clusters but on bioassays of to-be-repurposed medications as well as on genomics, transcriptomics, proteomics, metabolomics, epigenomics, microbiomics, and pharmacogenomics analyses blinded to phenotypic data. Unique features of this cohort study include (1) a reverse biology-to-phenotype direction of biomarker development in which clinical, imaging, and mobile health technologies are subordinate to biological signals of interest; (2) hypothesis free, causally- and data driven-based analyses; (3) inclusive recruitment of patients with neurodegenerative disorders beyond clinical criteria-meeting patients with Parkinson's and Alzheimer's diseases, and (4) a large number of longitudinally followed participants. The parallel development of serum bioassays will be aimed at linking biologically suitable subjects to already available drugs with repurposing potential in future proof-of-concept adaptive clinical trials. Although many challenges are anticipated, including the unclear pathogenic relevance of identifiable biological signals and the possibility that some signals of importance may not yet be measurable with current technologies, this cohort study abandons the anchoring role of clinico-pathologic criteria in favor of biomarker-driven disease subtyping to facilitate future biosubtype-specific disease-modifying therapeutic efforts.

Cardiopulmonary imaging in sarcoidosis.

Sarcoidosis is a disease with protean clinical manifestations ranging from no symptoms to sudden death. Radiologic tests are often the key to diagnosis. In this article, the authors review current imaging techniques and discuss emerging technologies used in the noninvasive cardiopulmonary evaluation of the patient who has sarcoidosis.

Meniscal gymnastics: common and uncommon locations of meniscal flip and flop.

The majority of knee magnetic resonance imaging examinations are performed for meniscal evaluations. Displaced meniscal tears including free meniscal fragments are an important diagnosis as most of these tears are unstable and require surgical intervention. Magnetic resonance imaging can be an invaluable tool in the arthroscopic search for a free meniscal fragment. In addition to the commonly seen bucket-handle tears flipped into the intercondylar notch, it is important to be aware of less common locations where menisci may be displaced. First, we briefly summarize the basic meniscal anatomy and some of the more common tear patterns. We then investigate the broad range of meniscal migration.

Role of Imaging in Acute Ischemic Stroke.

Rapid multimodal imaging is essential in the workup and management of acute ischemic stroke. Early parenchymal findings on noncontrast computed tomography or standard magnetic resonance imaging are used to triage patients for intravenous thrombolysis and to provide insight on prognosis. In the wake of recent endovascular stroke trials, advanced techniques including perfusion imaging and noninvasive vascular imaging are becoming important tools to guide potential endovascular treatment or expand therapy windows. Advanced imaging is also important in pediatric ischemic stroke which requires a slightly different workflow and treatment approach. Here, we will discuss key imaging findings in acute ischemic stroke, as well as the present and future of neuroimaging in light of recent and ongoing clinical trials.

Radiological manifestations of sarcoidosis.

Sarcoidosis is an immune system disorder characterised by non-necrotising granulomas. Pulmonary involvement is the most common presentation of sarcoidosis, but it can manifest in any organ. Other commonly involved organ systems include the lymph nodes (especially the intrathoracic nodes); the skin; the eyes; the liver; the heart; and the nervous, musculoskeletal, renal, and endocrine systems. The typical and atypical imaging features of multisystemic involvement of sarcoidosis have been discussed with review of the gamut of radiological manifestations of thoracic, cardiac, CNS, abdominal and musculoskeletal sarcoidosis.

Final infarct volume discriminates outcome in mild strokes.

INTRODUCTION: Knowledge of whether final infarct volume (FIV) predicts disability after mild stroke is limited. We sought to determine if FIV could differentiate good versus poor outcome after mild stroke. METHODS: We retrospectively identified 65 patients with mild stroke (National Institutes of Health Stroke Scale≤5) in a multicenter registry of 2453 patients. We evaluated associations between FIV and clinical outcome and evaluated the optimal FIV threshold that discriminated favorable (modified Rankin scale (mRS) 0-1) versus poor (mRS 2-6) outcome. RESULTS: The FIV cut-point of 20 mL differentiated favorable and poor outcomes (area under curve (AUC) 0.73, 95% confidence interval: 0.58-0.88). Favorable outcome was observed in 37/45 (82%) with FIV<20 mL, compared to 5/14 (36%) with FIV≥20 mL (p<0.01). FIV≥20 mL remained strongly associated with poor outcome independent of age, gender, stroke severity, Alberta Stroke Program Early CT Score (ASPECTS), and proximal arterial occlusion. CONCLUSION: In our small sample size, an FIV of 20 mL best differentiated between the likelihood of good versus poor outcome in patients with mild stroke. Further validation of infarct volume as a surrogate marker in mild stroke is warranted.

Target definition for malignant gliomas: no difference in radiation treatment volumes between 1.5T and 3T magnetic resonance imaging.

PURPOSE: Currently, most high-grade glioma patients undergo a 1.5T brain magnetic resonance (MR) for radiation treatment planning. We hypothesized that 3T MR imaging (MRI) scanning is superior to 1.5T due to higher signal-to-noise ratio (SNR), and thus will result in more accurate quantification of tumor volumes. The purpose of this prospective study was to determine differences in radiation planning volumes for high-grade gliomas when scanned on 3T MR versus 1.5T MR. METHODS AND MATERIALS: In this prospective controlled trial, 23 patients with high-grade gliomas underwent brain MRI scanning in both 1.5T and 3T field strengths within a 24-hour period; no steroids or treatment changes were made in-between scans. After 3 investigators contoured the T2 fast low-angle inversion recovery (FLAIR) abnormality (gross tumor volumes or [GTV]) for all patients, clinical target volume (CTV) and planning treatment volumes (PTV) were defined. Calculations by an independent investigator included volumes, standard deviations, SNRs, and contrast-to-noise ratios (CNRs); statistical analysis was performed on raw data. RESULTS: Planning treatment volume ratios (3T:1.5T) for each investigator were 0.95 ± 0.12 (range, 0.64-1.10), 0.98 ± 0.10 (range, 0.64-1.16), and 0.99 ± 0.06 (range, 0.86-1.13). By paired 2-tailed t test, these volumes were not statistically different (P = .051), although there is a trend to 3T producing smaller volumes than 1.5T. Dice similarity coefficients were 0.90 ± 0.05, 0.90 ± 0.06, and 0.91 ± 0.05 for the investigators. CONCLUSIONS: Planning target volumes for high-grade gliomas were similar at 3T and 1.5T MR using our standard imaging protocols. However, in some patients, the 3T MR may reveal substantially smaller tumor volume due to inferior conspicuity of the lesion. These findings imply that while overall the radiation target volumes are comparable, there are differences in CNR and SNR that lead to differences in individual patients. The 1.5T may be better for gaining conspicuity of the tumor.

Promotion as a clinician educator in academic radiology departments: guidelines at three major institutions.

Faculty promotion within an academic department of radiology may place emphasis on scientific research, administrative contributions, educational contributions, or a combination of all endeavors that enrich the department and further its academic mission. For those departments considering the establishment of a promotion pathway that emphasizes teaching talents and education-oriented research, the authors provide examples of three different clinician-educator faculty appointment and promotion schemes. Faculty development and defining scholarly work as a clinician-educator, as well as documentation of academic productivity within this pathway, are discussed.

Impact of Preoperative 64-Slice CT Scanning on Mini-Maze Atrial Fibrillation Surgery.

BACKGROUND: : Multidetector computed tomography (MDCT) is emerging as a powerful noninvasive diagnostic tool. The appropriate role of this technique in the preoperative evaluation of cardiovascular disease has yet to be fully defined. Atrial fibrillation is the most common sustained cardiac arrhythmia, and novel minimally invasive surgical techniques have been developed to treat this condition by electrically isolating the pulmonary veins. The ideal methodology to preoperatively evaluate these patients remains debatable. We hypothesized that 64-slice CT could significantly affect perioperative planning. METHODS: : Thirty-six consecutive patients who consented to undergo minimally invasive pulmonary vein isolation at our institution underwent a preoperative 64-slice cardiac CT scan. All cardiac and noncardiac abnormalities were recorded, and modifications to the initial surgical plan were documented. RESULTS: : The mean patient age was 64.4 ± 11.9 years [26 men (72.2%), 17 with known coronary artery disease (47.2%)]. Preoperative CT scanning detected 12 patients with abnormal pulmonary venous anatomy (33.3%), 3 with left atrial thrombus (8.3%), and 17 with significant coronary artery disease (47.2%). Furthermore, 20 studies (55.6%) detected pulmonary abnormalities (including 11 nodules). Preoperative scanning significantly altered surgical planning in 10 cases (27.8%). Alterations in patient treatment included preoperative invasive angiography, conversion of the mini-maze to an open chest procedure, alteration of surgical approach, and postponement/cancellation. CONCLUSIONS: : Sixty-four-slice CT scanning is a safe, rapid, and accurate procedure with important ramifications for surgical planning. This methodology could become an alternative approach to screen preoperative cardiac surgical patients.