Background For the past decade ¹⁸F-fluoro-ethyl-l-tyrosine (FET) and ¹⁸F-fluoro-deoxy-glucose (FDG) positron emission tomography (PET) have been used for the assessment of patients with brain tumor. However, direct comparison studies reported only limited numbers of patients. Our purpose was to compare the diagnostic performance of FET and FDG-PET. Methods We examined studies published between January 1995 and January 2015 in the PubMed database. To be included the study should: (i) use FET and FDG-PET for the assessment of patients with isolated brain lesion and (ii) use histology as the gold standard. Analysis was performed on a per patient basis. Study quality was assessed with STARD and QUADAS criteria. Results Five studies (119 patients) were included. For the diagnosis of brain tumor, FET-PET demonstrated a pooled sensitivity of 0.94 (95% CI: 0.79–0.98) and pooled specificity of 0.88 (95% CI: 0.37–0.99), with an area under the curve of 0.96 (95% CI: 0.94–0.97), a positive likelihood ratio (LR+) of 8.1 (95% CI: 0.8–80.6), and a negative likelihood ratio (LR−) of 0.07 (95% CI: 0.02–0.30), while FDG-PET demonstrated a sensitivity of 0.38 (95% CI: 0.27–0.50) and specificity of 0.86 (95% CI: 0.31–0.99), with an area under the curve of 0.40 (95% CI: 0.36–0.44), an LR+ of 2.7 (95% CI: 0.3–27.8), and an LR– of 0.72 (95% CI: 0.47–1.11). Target-to-background ratios of either FDG or FET, however, allow distinction between low- and high-grade gliomas (P > .11). Conclusions For brain tumor diagnosis, FET-PET performed much better than FDG and should be preferred when assessing a new isolated brain tumor. For glioma grading, however, both tracers showed similar performances.

BACKGROUND AND PURPOSE: Both ASPECTS and core volume on CTP are used to estimate infarct volume in acute ischemic stroke. To evaluate the potential role of ASPECTS for acute endovascular treatment decisions, we studied the correlation between ASPECTS and CTP core, depending on the timing and the presence of large-vessel occlusion. MATERIALS AND METHODS: We retrospectively reviewed all MCA acute ischemic strokes with standardized reconstructions of CTP maps entered in the Acute STroke Registry and Analysis of Lausanne (ASTRAL) registry. Correlation between ASPECTS and CTP core was determined for early (<6 hours) versus late (6–24 hours) times from stroke onset and in the presence versus absence of large-vessel occlusion. We used correlation coefficients and adjusted multiple linear regression models. RESULTS: We included 1046 patients with a median age of 71.4 years (interquartile range, IQR = 59.8–79.4 years), an NIHSS score of 12 (IQR, 6–18), an ASPECTS of 9 (IQR, 7–10), and a CTP core of 13.6 mL (IQR, 0.6–52.8 mL). The overall correlation between ASPECTS and CTP core was moderate (ρ = –0.49, P < .01) but significantly stronger in the late-versus-early window (ρ = –0.56 and ρ = –0.48, respectively; P = .05) and in the presence versus absence of large-vessel occlusion (ρ = –0.40 and ρ = –0.20, respectively; P < .01). In the regression model, the independent association between ASPECTS and CTP core was confirmed and was twice as strong in late-arriving patients with large-vessel occlusion (β = –0.21 per 10 mL; 95% CI, −0.27 to –0.15; P < .01) than in the overall population (β = –0.10; 95% CI, −0.14 to –0.07; P < .01). CONCLUSIONS: In a large cohort of patients with acute ischemic stroke, we found a moderate correlation between ASPECTS and CTP core. However, this was stronger in patients with large-vessel occlusion and longer delay from stroke onset. Our results could support the use of ASPECTS as a surrogate marker of CTP core in late-arriving patients with acute ischemic stroke with large-vessel occlusion.

BACKGROUND: The relative value of computed tomography (CT) and magnetic resonance imaging (MRI) in acute ischemic stroke (AIS) is debated. In May 2018, our center transitioned from using CT to MRI as first-line imaging for AIS. This retrospective study aims to assess the effects of this paradigm change on diagnosis and disability outcomes. METHODS: We compared all consecutive patients with confirmed diagnosis of AIS admitted to our center during the MRI-period (May 2018–August 2022) and an identical number of patients from the preceding CT-period (December 2012–April 2018). Univariable and multivariable analyses were performed to evaluate outcomes, including the number and delay of imaging exams, the rate of missed strokes, stroke mimics treated with thrombolysis, undetermined stroke mechanisms, length of hospitalization, and 3-month disability. RESULTS: The median age of the 2972 included patients was 76 years (interquartile range, 65–84), and 46% were female. In the MRI-period, 80% underwent MRI as first acute imaging. The proportion of patients requiring a second acute imaging modality for diagnostic ± revascularization reasons increased from 2.1% to 5% ( P _unadj <0.05), but it decreased in the subacute phase from 79.0% to 60.1% ( P _adj <0.05). In thrombolysis candidates, there was a 2-minute increase in door-to-imaging delay ( P _adj <0.05). The rates of initially missed AIS diagnosis was similar (3.8% versus 4.4%, P _adj =0.32) and thrombolysis in stroke mimics decreased by half (8.6% versus 4.3%; P _adj <0.05). Rates of unidentified stroke mechanism at hospital discharge were similar (22.8% versus 28.1%; P _adj =0.99). The length of hospitalization decreased from 9 (interquartile range, 6–14) to 7 (interquartile range, 4–12) days ( P _adj =0.62). Disability at 3 months was similar (common adjusted odds ratio for favorable Rankin shift, 0.98 [95% CI, 0.71–1.36]; P _adj =0.91), as well as mortality and symptomatic intracranial hemorrhage. CONCLUSIONS: A paradigm shift from CT to MRI as first-line imaging for AIS seems feasible in a comprehensive stroke center, with a minimally increased delay to imaging in thrombolysis candidates. MRI was associated with reduced thrombolysis rates of stroke mimics and subacute neuroimaging needs.

Brain-injured patients in a state of cognitive motor dissociation (CMD) exhibit a lack of command following using conventional neurobehavioral examination tools but a high level of awareness and language processing when assessed using advanced imaging and electrophysiology techniques. Because of their behavioral unresponsiveness, patients with CMD may seem clinically indistinguishable from those with a true disorder of consciousness that affects awareness on a substantial level (coma, vegetative state/unresponsive wakefulness state, or minimally conscious state minus). Yet, by expanding the range of motor testing across limb, facial, and ocular motricity, we may detect subtle, purposeful movements even in the subset of patients classified as vegetative state/unresponsive wakefulness state. We propose the term of clinical CMD to describe patients showing these slight but determined motor responses and exhibiting a characteristic akinetic motor behavior as opposed to a pyramidal motor system behavior. These patients may harbor hidden cognitive capabilities and significant potential for a good long-term outcome. Indeed, we envision CMD as ranging from complete (no motor response) to partial (subtle clinical motor response) forms, falling within a spectrum of progressively better motor output in patients with considerable cognitive capabilities. In addition to providing a decisional flowchart, we present this novel approach to classification as a graphical model that illustrates the range of clinical manifestations and recovery trajectories fundamentally differentiating true disorders of consciousness from the spectrum of CMD.

Summary: Aim: MRI and PET with 18F-fluoro-ethyl-tyro- sine (FET) have been increasingly used to evaluate patients with gliomas. Our purpose was to assess the additive value of MR spectroscopy (MRS), diffusion imaging and dynamic FET-PET for glioma grading. Patients, methods: 38 patients (42 ± 15 aged, F/M: 0.46) with untreated histologically proven brain gliomas were included. All underwent conventional MRI, MRS, diffusion sequences, and FET-PET within 3±4 weeks. Performances of tumour FET time-activity-curve, early-to-middle SUVmax ratio, choline / creatine ratio and ADC histogram distribution pattern for gliomas grading were assessed, as compared to histology. Combination of these parameters and respective odds were also evaluated. Results: Tumour time-activity- curve reached the best accuracy (67%) when taken alone to distinguish between low and high-grade gliomas, followed by ADC histogram analysis (65%). Combination of time-activity-curve and ADC histogram analysis improved the sensitivity from 67% to 86% and the specificity from 63-67% to 100% (p < 0.008). On multivariate logistic regression analysis, negative slope of the tumour FET time-activity-curve however remains the best predictor of high-grade glioma (odds 7.6, SE 6.8, p = 0.022). Conclusion: Combination of dynamic FET-PET and diffusion MRI reached good performance for gliomas grading. The use of FET-PET/MR may be highly relevant in the initial assessment of primary brain tumours.