Impact of Working Experience on Image Perception and Image Evaluation Approaches in Stroke Imaging: Results of an Eye-Tracking Study.

PURPOSE: Higher rates of missed pathologies, caused by a lack of professional experience or systematic search, suggest that a methodical approach to radiological analysis can be learned. Thus, the aim of this study is to investigate the efficiency of different principles of screening stroke CTs for cerebrovascular diseases between radiologists and neuroradiologists with different levels of experience in relation to professional experience. METHODS: A set of anonymous CT images of 20 patients, with a suspected stroke, was individually presented to 12 radiologists with different levels of professional experience. Meanwhile, their fixation position was recorded by an eye-tracking system. For statistical analysis, the interobserver variability and accuracy of lesion detection were evaluated, taking the individual level of professional experience into account. RESULTS: The sensitivity of the observer depends on the professional experience, also determined by a systematic observation sequence and knowledge of the course of the disease. The duration of eye fixation with inexperienced assessors was significantly longer for conspicuous findings, while experienced assessors were more likely to fix clinically relevant regions. The retention time of ocular fixation in important pathological findings did not differ significantly between those groups. CONCLUSION: Our results indicate that experienced radiologists are reducing the number of missed findings through a systematic approach and targeted inspection of important regions. Through raising the awareness of analyzing CT images in systematic patterns, physicians at all levels of experience seem to be able to improve their performance. KEY POINTS: · Experienced radiologists improve detection rates through targeted inspection of clinically important regions.. · Experienced radiologists reduce time spent on analysis through focused visual attention.. · All levels of experience improve their performance by analyzing CT images systematically.. CITATION FORMAT: · Kammerer S, Schülke C, Leclaire MD et al. Impact of Working Experience on Image Perception and Image Evaluation Approaches in Stroke Imaging: Results of an Eye-Tracking Study. Fortschr Röntgenstr 2019; 191: 836 - 844.

The difficulty of predicting clinical outcome after intended submaximal resection of large vestibular Schwannomas.

INTRODUCTION: Intended subtotal resection of large vestibular schwannomas (T4a and b according to the Hannover classification system) has been shown to be safe and, in combination with stereotactic radiosurgery, might enable sufficient tumor control. However, risk factors for postoperative neurological deterioration in these surgically challenging lesions are largely unknown. METHODS: Pre- and postoperative symptoms, clinical and radiological data of patients who underwent intended subtotal resection for vestibular schwannoma in our department between 2010 and 2014 were reviewed. Risk factors for postoperative neurological deterioration were analyzed in uni- and multivariate analyses. RESULTS: 63 patients harboring T4a (N = 33, 52%) or T4b (N = 30, 48%) tumors were included. At time of discharge, facial nerve and hearing function had deteriorated from a serviceable to a non-serviceable level (H&B grades I + II vs. >II) in 24% (N = 15/63) and 21% (N = 6/29), respectively. Deterioration of vertigo was more common after near (N = 3/9, 33% vs. 2/38, 5%) than after subtotal resection (<.25 ccm vs. ≥ .25 ccm tumor remnant on the initial postoperative MRI; p = .042). No further correlation with patient age, sex, neurofibromatosis, resection extent and tumor volume, or -cyst volume was found. Patients were reevaluated after a median of 3 months after surgery. At that time, facial nerve function and hearing had both decreased from a preoperative serviceable to a non-serviceable level in 5%. In univariate analyses, risk of deterioration of facial nerve function increased with preoperative tumor volume (p = .037). CONCLUSION: Intended submaximal resection provides satisfactory neurological outcome for patients with large VS. Risk factors for postoperative neurological deterioration remain unclear.

Ischemic Stroke: What Does the Histological Composition Tell Us About the Origin of the Thrombus?

BACKGROUND AND PURPOSE: The introduction of stent retrievers allows for a complete extraction and histological analysis of human thrombi. Ischemic stroke is a major health issue, and differentiation of underlying causes is highly relevant to prevent recurrent stroke. Therefore, histopathologic analysis of the embolic clots after removal may provide valuable information about underlying pathologies. This study analyzes histological clot composition and aims to identify specific patterns that might help to distinguish causes of ischemic stroke. METHODS: Patients with occlusion of the carotid-T or middle cerebral artery who underwent thrombectomy at our university medical center between December 2013 and February 2016 were included. Samples were histologically analyzed (hematoxylin and eosin, Elastica van Gieson, and Prussian blue), additionally immunohistochemistry for CD3, CD20, and CD68/KiM1P was performed. These data, along with additional clinical and interventional parameters, were compared for different stroke subtypes, as defined by the TOAST (Trial of Org 10172 in Acute Stroke Treatment) classification. RESULTS: One hundred eighty-seven patients were included, of these, in 77 patients, cardioembolic; in 46 patients, noncardioembolic; and in 64 patients, cryptogenic pathogenesis was determined. Cardioembolic thrombi had higher proportions of fibrin/platelets (P=0.027), less erythrocytes (P=0.005), and more leucocytes (P=0.026) than noncardioembolic thrombi. We observed a strong overlap of cryptogenic strokes and cardioembolic strokes concerning thrombus histology. The immunohistochemical parameters CD3, CD20, and CD68/KiM1P showed no statistically noticeable differences between stroke subtypes. CONCLUSIONS: Histological thrombus features vary significantly according to the underlying cause and may help to differentiate between cardioembolic and noncardioembolic stroke. In addition, our study supports the hypothesis that most cryptogenic strokes have a cardioembolic cause.

Computed Tomographic Blend Sign Is Associated With Computed Tomographic Angiography Spot Sign and Predicts Secondary Neurological Deterioration After Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: Significant early hematoma growth in patients with intracerebral hemorrhage is an independent predictor of poor functional outcome. Recently, the novel blend sign (BS) has been introduced as a new imaging sign for predicting hematoma growth in noncontrast computed tomography. Another parameter predicting increasing hematoma size is the well-established spot sign (SS) visible in computed tomographic angiography. We, therefore, aimed to clarify the association between established SS and novel BS and their values predicting a secondary neurological deterioration. METHODS: Retrospective study inclusion criteria were (1) spontaneous intracerebral hemorrhage confirmed on noncontrast computed tomography and (2) noncontrast computed tomography and computed tomographic angiography performed on admission within 6 hours after onset of symptoms. We defined a binary outcome (secondary neurological deterioration versus no secondary deterioration). As secondary neurological deterioration, we defined (1) early hemicraniectomy under standardized criteria or (2) secondary decrease of Glasgow Coma Scale of >3 points, both within the first 48 hours after symptom onset. RESULTS: Of 182 patients with spontaneous intracerebral hemorrhage, 37 (20.3%) presented with BS and 39 (21.4%) with SS. Of the 81 patients with secondary deterioration, 31 (38.3%) had BS and SS on admission. Multivariable logistic regression analysis identified hematoma volume (odds ratio, 1.07 per mL; P≤0.001), intraventricular hemorrhage (odds ratio, 3.08; P=0.008), and the presence of BS (odds ratio, 11.47; P≤0.001) as independent predictors of neurological deterioration. CONCLUSIONS: The BS, which is obtainable in noncontrast computed tomography, shows a high correlation with the computed tomographic angiography SS and is a reliable predictor of secondary neurological deterioration after spontaneous intracerebral hemorrhage.

Progressive Multifocal Leukoencephalopathy after Ibrutinib Therapy for Chronic Lymphocytic Leukemia.

Progressive multifocal leukoencephalopathy (PML) is a devastating neurological disease observed nearly exclusively in immunocompromised patients. Recently, the introduction of monoclonal antibodies significantly inhibiting the immune system such as rituximab has led to an increase in PML cases. Although rituximab-based immunochemotherapy remains the standard of treatment for chronic lymphocytic leukemia (CLL), the importance of Bruton's tyrosine kinase inhibitors such as ibrutinib is steadily increasing. However, long-term experiences regarding possible side effects of these new substances are rare. Here, we report the development of eventually fatal PML possibly associated with ibrutinib therapy for CLL after multiple prior treatment lines, including rituximab. To the best of our knowledge, this is the first study to report such findings. Since the last course of rituximab was applied over 3 years ago, it is conceivable that the strong B cell inhibition by ibrutinib led to PML. With increased awareness of this potential side effect, further clinical studies are certainly warranted to evaluate this possible association.

Automated assessment of early hypoxic brain edema in non-enhanced CT predicts outcome in patients after cardiac arrest.

INTRODUCTION: Early prediction of potential neurological recovery in patients after cardiac arrest is challenging. Recent studies suggest that the densitrometic gray-white matter ratio (GWR) determined from cranial computed tomography (CT) scans may be a reliable predictor of poor outcome. We evaluated an automated, rater independent method to determine GWR in CT as an early objective imaging predictor of clinical outcome. METHODS: We analyzed imaging data of 84 patients after cardiac arrest that underwent noncontrast CT within 24h after arrest. To determine GWR in CT we applied two methods using a recently published automated probabilistic gray-white matter segmentation algorithm (GWR_aut) and conventional manual measurements within gray-white regions of interest (GWR_man). Neurological outcome was graded by the cerebral performance category (CPC). As part of standard routine CPC was assessed by the treating physician in the intensive care unit at admission and at discharge to normal ward. The performance of GWR measures (automated and manual) to predict the binary clinical endpoints of poor (CPC3-5) and good outcome (CPC1-2) was assessed by ROC analysis with increasing discrimination thresholds. Results of GWR_aut were compared to GWR_man of two raters. RESULTS: Of 84 patients, 55 (65%) showed a poor outcome. ROC curve analysis revealed reliable outcome prediction of GWR_aut (AUC 0.860) and GWR_man (AUC 0.707 and 0.699, respectively). Predictive power of GWR_aut was higher than GWR_man by each rater (p=0.019 and p=0.021, respectively) at an optimal cut-off of 1.084 to predict poor outcome (optimal criterion with 92.7% sensitivity, 72.4% specificity). Interrater reliability of GWR_man by intra-class correlation coefficient (ICC) was moderate (0.551). CONCLUSION: Automated quantification of GWR in CT may be used as an objective observer-independent imaging marker for outcome in patients after cardiac arrest.

Intraoperative myelography of traumatic spine injury in patients with ankylosing spondylitis. Technical note.

BACKGROUND: Ankylosing spondylitis (AS) is an autoimmune inflammatory arthritis causing ossifications and rigidity of the spinal column. Patients with AS have a high incidence of spinal fractures, especially in the cervical spine, with a high rate of epidural hematomas. These have hazardous consequences, including neurological sequelae, and high morbidity and mortality. Diagnostics rely on CT and MRI scans, and therapy, usually open decompression and fixation, has to be done as soon as possible to enable recovery. However, in many cases, performing MRI scans is not possible for several reasons. METHODS: We present a case of an AS patient with paraparesis below T-8 after a fall who was not able to undergo MRI scan due to severe obesity, hyperkyphosis, and mechanical ventilation. CT scan did not demonstrate any fractures or hemorrhages in the thoracic spine and in addition a standard myelography could not be performed due to ossifications of ligaments. As an alternative, we performed an intra-operative myeolgraphy. Intra-operative installation of a lumbar drain made a myelography and post-myelographic CT scan feasible. RESULTS: The scan revealed a contrast stop at T-10 and subsequently operative decompression and evacuation of the hematoma were performed. CONCLUSIONS: We present a quick and safe technique, performed in the operation room (OR), to detect intra-spinal lesions in patients with contraindications for MRI, or for cases where MRI scans cannot be performed.

Computed Tomography Perfusion Improves Diagnostic Accuracy in Acute Posterior Circulation Stroke.

BACKGROUND AND PURPOSE: Computed tomography perfusion (CTP) has a high diagnostic value in the detection of acute ischemic stroke in the anterior circulation. However, the diagnostic value in suspected posterior circulation (PC) stroke is uncertain, and whole brain volume perfusion is not yet in widespread use. We therefore studied the additional value of whole brain volume perfusion to non-contrast CT (NCCT) and CT angiography source images (CTA-SI) for infarct detection in patients with suspected acute ischemic PC stroke. METHODS: This is a retrospective review of patients with suspected stroke in the PC in a database of our stroke center (n = 3,011) who underwent NCCT, CTA and CTP within 9 h after stroke onset and CT or MRI on follow-up. Images were evaluated for signs and pc-ASPECTS locations of ischemia. Three imaging models - A (NCCT), B (NCCT + CTA-SI) and C (NCCT + CTA-SI + CTP) - were compared with regard to the misclassification rate relative to gold standard (infarction in follow-up imaging) using the McNemar's test. RESULTS: Of 3,011 stroke patients, 267 patients had a suspected stroke in the PC and 188 patients (70.4%) evidenced a PC infarct on follow-up imaging. The sensitivity of Model C (76.6%) was higher compared with that of Model A (21.3%) and Model B (43.6%). CTP detected significantly more ischemic lesions, especially in the cerebellum, posterior cerebral artery territory and thalami. CONCLUSIONS: Our findings in a large cohort of consecutive patients show that CTP detects significantly more ischemic strokes in the PC than CTA and NCCT alone.

The Value of 5-Aminolevulinic Acid in Low-grade Gliomas and High-grade Gliomas Lacking Glioblastoma Imaging Features: An Analysis Based on Fluorescence, Magnetic Resonance Imaging, 18F-Fluoroethyl Tyrosine Positron Emission Tomography, and Tumor Molecular Factors.

BACKGROUND: Approximately 20% of grade II and most grade III gliomas fluoresce after 5-aminolevulinic acid (5-ALA) application. Conversely, approximately 30% of nonenhancing gliomas are actually high grade. OBJECTIVE: The aim of this study was to identify preoperative factors (ie, age, enhancement, 18F-fluoroethyl tyrosine positron emission tomography [F-FET PET] uptake ratios) for predicting fluorescence in gliomas without typical glioblastomas imaging features and to determine whether fluorescence will allow prediction of tumor grade or molecular characteristics. METHODS: Patients harboring gliomas without typical glioblastoma imaging features were given 5-ALA. Fluorescence was recorded intraoperatively, and biopsy specimens collected from fluorescing tissue. World Health Organization (WHO) grade, Ki-67/MIB-1 index, IDH1 (R132H) mutation status, O-methylguanine DNA methyltransferase (MGMT) promoter methylation status, and 1p/19q co-deletion status were assessed. Predictive factors for fluorescence were derived from preoperative magnetic resonance imaging and F-FET PET. Classification and regression tree analysis and receiver-operating-characteristic curves were generated for defining predictors. RESULTS: Of 166 tumors, 82 were diagnosed as WHO grade II, 76 as grade III, and 8 as glioblastomas grade IV. Contrast enhancement, tumor volume, and F-FET PET uptake ratio >1.85 predicted fluorescence. Fluorescence correlated with WHO grade (P < .001) and Ki-67/MIB-1 index (P < .001), but not with MGMT promoter methylation status, IDH1 mutation status, or 1p19q co-deletion status. The Ki-67/MIB-1 index in fluorescing grade III gliomas was higher than in nonfluorescing tumors, whereas in fluorescing and nonfluorescing grade II tumors, no differences were noted. CONCLUSION: Age, tumor volume, and F-FET PET uptake are factors predicting 5-ALA-induced fluorescence in gliomas without typical glioblastoma imaging features. Fluorescence was associated with an increased Ki-67/MIB-1 index and high-grade pathology. Whether fluorescence in grade II gliomas identifies a subtype with worse prognosis remains to be determined.

Acute tonsillar cerebellar herniation in a patient with traumatic dural tear and VAC therapy after complex trauma.

BACKGROUND CONTEXT: Cases of cerebral hypotension and tonsillar herniation after accidental lumbar cerebrospinal fluid (CSF) drainage or chest tube drainage with intrathoracic CSF leaks have been reported. To the authors' knowledge, this case presents the first report of severe intracranial hypotension because of suction of CSF by a Vacuum-Assisted Closure (VAC) device. PURPOSE: The purpose of this study was to report a life-threatening intracranial hypotension in a polytraumatized patient after VAC therapy. STUDY DESIGN: This study is a case report. METHODS: A 23-year-old woman suffered of a Grade 3 open pelvic fracture after a motor vehicle accident. After a VAC therapy, the patient became nonresponsive. A cranial computer tomography (CCT) showed signs of intracranial hypotension with narrowing of the basal cisterns and sagging of the cerebellar tonsils. The VAC was removed. Further neuroradiological diagnostic showed a tear in the dural sac at the L5-S1 level. The patient consequently underwent neurosurgery. After a dural patch, she was oriented postoperatively and the CCT improved to a normal state. RESULTS: Fifteen days after admission, the patient was discharged without neurologic sequelae. CONCLUSIONS: Severely injured patients undergoing VAC therapy with secondary neurologic deterioration not because of head injury should be appropriately diagnosed to rule out dural laceration and cranial hypotension.