Visual Illusions in Radiology: Untrue Perceptions in Medical Images and Their Implications for Diagnostic Accuracy.

Errors in radiologic interpretation are largely the result of failures of perception. This remains true despite the increasing use of computer-aided detection and diagnosis. We surveyed the literature on visual illusions during the viewing of radiologic images. Misperception of anatomical structures is a potential cause of error that can lead to patient harm if disease is seen when none is present. However, visual illusions can also help enhance the ability of radiologists to detect and characterize abnormalities. Indeed, radiologists have learned to exploit certain perceptual biases in diagnostic findings and as training tools. We propose that further detailed study of radiologic illusions would help clarify the mechanisms underlying radiologic performance and provide additional heuristics to improve radiologist training and reduce medical error.

Disseminated nocardiosis in an immunosuppressed patient with systemic lupus erythematosus and neuromyelitis optica spectrum disorder.

Opportunistic infections are an ongoing concern in patients with autoimmune disease who are being treated with immunosuppressive agents. Nocardiosis is an uncommon opportunistic infection which has been reported in association with immunosuppressed patients and autoimmune disease. It is challenging to diagnose and can have multisystem manifestations. Failure to diagnose and appropriately treat can result in significant mortality. We present a 49 year old woman with systemic lupus erythematosus and neuromyelitis optica spectrum disorder who was treated with mycophenolate mofetil, prednisone and recent plasmapheresis. She developed acute onset of shortness of breath and fevers and was ultimately diagnosed with disseminated nocardiosis with lung, brain and muscle abscesses.

Incomplete Cord Syndromes: Clinical and Imaging Review.

The ability to localize the three spinal tracts (corticospinal tract, spinothalamic tract, and dorsal [posterior] columns) involved in incomplete spinal cord syndromes at cross-sectional imaging and knowledge of the classic clinical manifestations of the various syndromes enable optimized imaging evaluation and provide clinicians with information that aids in diagnosis and treatment. The requisite knowledge for localizing these tracts is outlined. The authors review the spinal cord anatomy, blood supply, and course of these tracts and describe the various associated syndromes: specifically, dorsal cord, ventral cord, central cord, Brown-Séquard, conus medullaris, and cauda equina syndromes. In addition, they describe the anatomic basis for the clinical manifestation of each syndrome and the relevant imaging features of the classic causes of these entities. Knowledge of the anatomy and clinical findings of the spinal cord is essential for examining and treating patients with cord abnormalities. ©RSNA, 2018.

Imaging of Intracranial and Orbital Complications of Sinusitis and Atypical Sinus Infection: What the Radiologist Needs to Know.

Sinusitis is a common disease. Complications, however, are less common and can be life threatening. Major complications occur from extension of disease into the orbit and intracranial compartment and often require emergent treatment with intravenous (IV) antibiotics or operative intervention. Immunocompromised patients with acute sinusitis are susceptible to atypical infections, such as invasive fungal sinusitis, which is a surgical emergency. Therefore, it is important to accurately and promptly identify potentional complications of acute sinusitis to ensure appropriate treatment and minimize negative outcomes. This article reviews the imaging features of a spectrum of complications associated with acute sinusitis and atypical infections.

A score based on age and DWI volume predicts poor outcome following endovascular treatment for acute ischemic stroke.

BACKGROUND AND AIMS: The Houston Intra-Arterial Therapy score predicts poor functional outcome following endovascular treatment for acute ischemic stroke based on clinical variables. The present study sought to (a) create a predictive scoring system that included a neuroimaging variable and (b) determine if the scoring systems predict the clinical response to reperfusion. METHODS: Separate datasets were used to derive (n = 110 from the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution 2 study) and validate (n = 125 from Massachusetts General Hospital) scoring systems that predict poor functional outcome, defined as a modified Rankin Scale score of 4-6 at 90 days. RESULTS: Age (P < 0·001; ß = 0·087) and diffusion-weighted imaging volume (P = 0·023; ß = 0·025) were the independent predictors of poor functional outcome. The Stanford Age and Diffusion-Weighted Imaging score was created based on the patient's age (0-3 points) and diffusion-weighted imaging lesion volume (0-1 points). The percentage of patients with a poor functional outcome increased significantly with the number of points on the Stanford Age and Diffusion-Weighted Imaging score (P < 0·01 for trend). The area under the receiver operating characteristic curve for the Stanford Age and Diffusion-Weighted Imaging score was 0·82 in the derivation dataset. In the validation cohort, the area under the receiver operating characteristic curve was 0·69 for the Stanford Age and Diffusion-Weighted Imaging score and 0·66 for the Houston Intra-Arterial Therapy score (P = 0·45 for the difference). Reperfusion, but not the interactions between the prediction scores and reperfusion, were predictors of outcome (P > 0·5). CONCLUSIONS: The Stanford Age and Diffusion-Weighted Imaging and Houston Intra-Arterial Therapy scores can be used to predict poor functional outcome following endovascular therapy with good accuracy. However, these scores do not predict the clinical response to reperfusion. This limits their utility as tools to select patients for acute stroke interventions.

Impact of pretreatment noncontrast CT Alberta Stroke Program Early CT Score on clinical outcome after intra-arterial stroke therapy.

BACKGROUND AND PURPOSE: The efficacy of intra-arterial treatment remains uncertain. Because most centers performing IAT use noncontrast CT (NCCT) imaging, it is critical to understand the impact of NCCT findings on treatment outcomes. This study aimed to compare functional independence and safety among patients undergoing intra-arterial treatment stratified by the extent of ischemic change on pretreatment NCCT. METHODS: The study cohort was derived from multicenter trials of the Penumbra System. Inclusion criteria were anterior circulation proximal occlusion, evaluable pretreatment NCCT, and known time to reperfusion. Ischemic change was quantified using the Alberta Stroke Program Early CT Score (ASPECTS) and stratified into 3 prespecified groups for comparison: 0 to 4 (most ischemic change) versus 5 to 7 versus 8 to 10 (least ischemic change). RESULTS: A total of 249 patients were analyzed: 40 with ASPECTS 0 to 4, 83 with ASPECTS 5 to 7, and 126 with ASPECTS 8 to 10. For ASPECTS 0 to 4, 5 to 7, and 8 to 10, respectively, good outcome (modified Rankin Scale score, 0-2) rates were 5%, 38.6%, and 46% (P<0.0001), and mortality rates were 55%, 28.9%, and 19% (P=0.0001). The only significant pairwise differences were between ASPECTS 0 to 4 and other groups. Symptomatic hemorrhage was more common with lower ASPECTS (P=0.02). Shorter time to reperfusion was significantly associated with better outcomes among patients with ASPECTS 8 to 10 (P=0.01). A similar relationship was seen for ASPECTS 5 to 7 but was not statistically significant. No such relationship was seen for ASPECTS 0 to 4. CONCLUSIONS: NCCT seems useful for excluding patients with the greatest burden of ischemic damage from futile intra-arterial treatment, which is unlikely to result in patient functional independence and increases the risk of hemorrhage.

Refining angiographic biomarkers of revascularization: improving outcome prediction after intra-arterial therapy.

BACKGROUND AND PURPOSE: Angiographic revascularization grading after intra-arterial stroke therapy is limited by poor standardization, making it unclear which scale is optimal for predicting outcome. Using recently standardized criteria, we sought to compare the prognostic performance of 2 commonly used reperfusion scales. METHODS: Inclusion criteria for this multicenter retrospective study were acute ischemic stroke attributable to middle cerebral artery M1 occlusion, intra-arterial therapy, and 90-day modified Rankin scale score. Post-intra-arterial therapy reperfusion was graded using the Thrombolysis in Myocardial Infarction (TIMI) and Modified Thrombolysis in Cerebral Infarction (mTICI) scales. The scales were compared for prediction of clinical outcome using receiver-operating characteristic analysis. RESULTS: Of 308 patients, mean age was 65 years, and median National Institutes of Health Stroke Scale score was 17. The mean time from stroke onset to groin puncture was 305 minutes. There was no difference in the time to treatment between patients grouped by final TIMI (ie, 0 versus 1 versus 2 versus 3) or mTICI grades (ie, 0 versus 1 versus 2a versus 2b versus 3). Good outcome (modified Rankin scale, 0-2) was achieved in 32.5% of patients, and mortality rate was 25.3% at 90 days. There was a 6.3% rate of parenchymal hematoma type 2. In receiver-operating characteristic analysis, mTICI was superior to TIMI for predicting 90-day modified Rankin scale 0 to 2 (c-statistic: 0.74 versus 0.68; P<0.0001). The optimal threshold for identifying a good outcome was mTICI 2b to 3 (sensitivity 78.0%; specificity 66.1%). CONCLUSIONS: mTICI is superior to TIMI for predicting clinical outcome after intra-arterial therapy. mTICI 2b to 3 is the optimal biomarker for procedural success.

Assessing variability in neurointerventional practice patterns for acute ischemic stroke.

BACKGROUND: Intra-arterial therapy (IAT) is increasingly used to treat patients with acute stroke with large vessel occlusions. There are minimal data and guidelines for treatment indications and performance standards. We aimed to gain a better understanding of real-world practice patterns for IAT. METHODS: An internet-based survey was launched to address six specific areas of IAT: practice setting, operator background, operational protocols, quality/safety, decision-making and treatment strategies. The survey invitation was distributed to members of multiple neurointerventional societies. RESULTS: Responses from 140 neurointerventionalists worldwide were analyzed. The median annual volume of IAT cases per institution was 40, and the median neurointerventional group size was three staff members. Independent predictors of case volume were presence of comprehensive stroke services and telestroke capability. The median minimum National Institutes of Health Stroke Scale score for treatment consideration was 8, although 60% of respondents reported no minimum score cut-off. There was no strict time window from symptom onset to treatment among 41% of respondents for anterior circulation strokes and among 56% for posterior circulation strokes, instead basing treatment decisions on clinical and imaging findings. Despite the emphasis on imaging-based selection, there was pronounced variability in the criteria used. Only 27% used one imaging approach exclusively. IAT following full- or partial-dose intravenous tissue plasminogen activator was performed by 89%. Mechanical devices were the predominant first-line therapy, but specific device usage depended on practice location. Approximately half preferred conscious sedation during IAT. CONCLUSIONS: This survey illustrates significant variation among neurointerventionalists in the real-world use of IAT. Our findings highlight the need for evidence-based practice guidelines.

Validating imaging biomarkers of cerebral edema in patients with severe ischemic stroke.

BACKGROUND: There is no validated neuroimaging marker for quantifying brain edema. We sought to test whether magnetic resonance imaging (MRI)-based metrics would reliably change during the early subacute period in a manner consistent with edema and whether they would correlate with relevant clinical endpoints. METHODS: Serial MRI studies from patients in the Echoplanar Imaging Thrombolytic Evaluation Trial with initial diffusion-weighted imaging (DWI) lesion volume >82 cm(3) were analyzed. Two independent readers outlined the hemisphere and lateral ventricle on the involved side and calculated respective volumes at baseline and days 3 to 5. We assessed interrater agreement, volume change between scans, and the association of volume change with early neurologic deterioration (National Institutes of Health Stroke Scale score worsening of ≥ 4 points), a 90-day modified Rankin scale (mRS) score of 0 to 4, and mortality. RESULTS: Of 12 patients who met study criteria, average baseline and follow-up DWI lesion size was 138 cm(3) and 234 cm(3), respectively. The mean time to follow-up MRI was 62 hours. Concordance correlation coefficients between readers were >0.90 for both hemisphere and ventricle volume assessment. Mean percent hemisphere volume increase was 16.2 ± 8.3% (P < .0001), and the mean percent ventricle volume decrease was 45.6 ± 16.9% (P < .001). Percent hemisphere growth predicted early neurologic deterioration (area under the curve [AUC] 0.92; P = .0005) and 90-day mRS 0 to 4 (AUC 0.80; P = .02). CONCLUSIONS: In this exploratory analysis of severe ischemic stroke patients, statistically significant changes in hemisphere and ventricular volumes within the first week are consistent with expected changes of cerebral edema. MRI-based analysis of hemisphere growth appears to be a suitable biomarker for edema formation.

Elderly patients are at higher risk for poor outcomes after intra-arterial therapy.

BACKGROUND AND PURPOSE: Conflicting data exist regarding outcomes after intra-arterial therapy (IAT) in elderly stroke patients. We compare safety and clinical outcomes of multimodal IAT in elderly versus nonelderly patients and investigate differences in baseline health and disability as possible explanatory factors. METHODS: Data from a prospectively collected institutional IAT database were analyzed comparing elderly (80 years or older) versus nonelderly patients. Baseline demographics, angiographic reperfusion (Thrombolysis in Cerebral Infarction scale score 2-3), rate of parenchymal hematoma type 2, and 90-day modified Rankin Scale scores were compared in univariate and multivariate analyses. RESULTS: There were 49 elderly and 130 nonelderly patients treated between 2005 and 2010. Between the 2 cohorts, there was no significant difference in Thrombolysis in Cerebral Infarction 2 to 3 reperfusion (71% vs 75%; P=0.57), time to reperfusion (P=0.77), or rate of parenchymal hematoma type 2 (4% vs 7%; P=0.73) after IAT. However, elderly patients had significantly lower rates of good outcome (modified Rankin Scale score 0-2: 2% vs 33%; P<0.0001) and higher mortality (59% vs 24%; P<0.0001) at 90 days. Atrial fibrillation, coronary artery disease, hypertension, hyperlipidema, and baseline disability were significantly more common in elderly patients. Adjusting for baseline disability, stroke severity, and reperfusion, elderly patients were 29-times more likely to be dependent or dead at 90 days (odds ratio, 28.7; 95% confidence interval, 3.2-255.7; P=0.003). CONCLUSIONS: Despite comparable rates of reperfusion and significant hemorrhage, elderly patients had worse clinical outcomes after IAT, which may relate, in part, to worse baseline health and disability. The use of IAT in the elderly should be performed after a careful analysis of the potential risks and benefits.

Endovascular treatment of acute ischemic stroke: current indications.

Endovascular stroke therapy is an effective means of achieving reperfusion in stroke patients with proximal cerebral artery occlusions. However, current guideline recommendations express uncertainty regarding the clinical efficacy of catheter-based treatments, given the lack of supportive trial data. A critical problem is that it remains unclear which patients will benefit from endovascular therapy. As such, patient selection is likely highly variable in clinical practice. This article will review the existing data to discuss the clinical and imaging factors that are relevant to patient outcomes, and which may be used to guide endovascular treatment decisions. Anterior circulation strokes represent the primary focus of this review.

Infarct volume is a pivotal biomarker after intra-arterial stroke therapy.

BACKGROUND AND PURPOSE: Pretreatment infarct volume appears to predict clinical outcome after intra-arterial therapy. To confirm the importance of infarct size in patients undergoing intra-arterial therapy, we sought to characterize the relationship between final infarct volume (FIV) and long-term functional outcome in a prospective cohort of endovascularly treated patients. METHODS: From our prospective intra-arterial therapy database, we identified 107 patients with acute ischemic stroke with anterior circulation proximal artery occlusions who underwent final infarct imaging and had 3-month modified Rankin Scale scores. Clinical, imaging, treatment, and outcome data were analyzed. RESULTS: Mean age was 66.6 years. Median admission National Institutes of Health Stroke Scale score was 17. Reperfusion (Thrombolysis In Cerebral Infarction 2A-3) was achieved in 78 (72.9%) patients. Twenty-seven (25.2%) patients achieved a 3-month good outcome (modified Rankin Scale 0-2), and 30 (28.0%) died. Median FIV was 71.4 cm(3). FIV independently correlated with functional outcome across the entire modified Rankin Scale. In receiver operating characteristic analysis, it was the best discriminator of both good outcome (area under the curve=0.857) and mortality (area under the curve=0.772). A FIV of approximately 50 cm(3) demonstrated the greatest accuracy for distinguishing good versus poor outcome, and a FIV of approximately 90 cm(3) was highly specific for a poor outcome. The interaction term between FIV and age was the only independent predictor of good outcome (P<0.0001). The impact of FIV was accentuated in patients <80 years. CONCLUSIONS: Among patients with anterior circulation acute ischemic stroke who undergo intra-arterial therapy, final infarct volume is a critical determinant of 3-month functional outcome and appears suitable as a surrogate biomarker in proof-of-concept intra-arterial therapy trials.

Evaluating the safety and effectiveness of percutaneous acetabuloplasty.

PURPOSE: To evaluate the safety and effectiveness of percutaneous acetabuloplasty in treating the pain and disability related to metastatic lesions of the acetabulum. MATERIALS AND METHODS: This institutional review board approved retrospective study examined 11 patients who underwent percutaneous acetabuloplasty in our hospital from April 2007 to June 2010. All patients gave informed consent prior to the procedure, and all records were HIPAA compliant. Chart review was performed to collect patient demographics and to assess pre- and post-treatment patient performance on the Visual Analog Scale, Functional Mobility Scale and Analgesic Scale. Paired testing comparing the pre- and post-treatment scores for each patient was performed using the Wilcoxon signed rank test. RESULTS: There were 11 procedures: 10 performed under CT guidance and one using fluoroscopic guidance. There was a statistically significant decrease in patient Visual Analog Scale score (p=0.001) and Functional Mobility Scale score (p=0.03) after treatment. There was no change in median Analgesic Scale scores pre- and post-treatment although paired testing revealed a trend towards reduced analgesic use postoperatively (p=0.06). There were no clinically significant complications in this series. CONCLUSION: Percutaneous acetabuloplasty appears to be safe and effective for improving the pain and decreased mobility secondary to metastatic lesions of the acetabulum.

Acute ischemic stroke: infarct core estimation on CT angiography source images depends on CT angiography protocol.

PURPOSE: To test whether the relationship between acute ischemic infarct size on concurrent computed tomographic (CT) angiography source images and diffusion-weighted (DW) magnetic resonance images is dependent on the parameters of CT angiography acquisition protocols. MATERIALS AND METHODS: This retrospective study had institutional review board approval, and all records were HIPAA compliant. Data in 100 patients with anterior-circulation acute ischemic stroke and large vessel occlusion who underwent concurrent CT angiography and DW imaging within 9 hours of symptom onset were analyzed. Measured areas of hyperintensity at acute DW imaging were used as the standard of reference for infarct size. Information regarding lesion volumes and CT angiography protocol parameters was collected for each patient. For analysis, patients were divided into two groups on the basis of CT angiography protocol differences (patients in group 1 were imaged with the older, slower protocol). Intermethod agreement for infarct size was evaluated by using the Wilcoxon signed rank test, as well as by using Spearman correlation and Bland-Altman analysis. Multivariate analysis was performed to identify predictors of marked (≥20%) overestimation of infarct size on CT angiography source images. RESULTS: In group 1 (n=35), median hypoattenuation volumes on CT angiography source images were slightly underestimated compared with DW imaging hyperintensity volumes (33.0 vs 41.6 mL, P=.01; ratio=0.83), with high correlation (ρ=0.91). In group 2 (n=65), median volume on CT angiography source images was much larger than that on DW images (94.8 vs 17.8 mL, P<.0001; ratio=3.5), with poor correlation (ρ=0.49). This overestimation on CT angiography source images would have inappropriately excluded from reperfusion therapy 44.4% or 90.3% of patients eligible according to DW imaging criteria on the basis of a 100-mL absolute threshold or a 20% or greater mismatch threshold, respectively. Atrial fibrillation and shorter time from contrast material injection to image acquisition were independent predictors of marked (≥20%) infarct size overestimation on CT angiography source images. CONCLUSION: CT angiography protocol changes designed to speed imaging and optimize arterial opacification are associated with significant overestimation of infarct size on CT angiography source images.