Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Context: Blood oxygenation level-dependent (BOLD)-weighted and vessel-encoded arterial spin labeling (VE-ASL) MRI provide complementary information and can be used in sequence to gauge hemodynamic contributions to cerebrovascular reactivity. Here, cerebrovascular reactivity is assessed using dual echo VE-ASL MRI to understand how VE labeling preparations influence BOLD and ASL contrast in flow-limited and healthy perfusion territories.', 'Patients (n=12; age=55 +/- 14 years; 6F/6M) presenting with ischemic steno-occlusive cerebrovascular disease underwent 3.0T angiographic imaging, T1 -weighted structural, and planning-free dual echo hypercarbic hyperoxic (i.e., carbogen) VE-ASL MRI. Vasculopathy extent, timecourses, and cerebrovascular reactivity (signal change and Z-statistic) for different VE-ASL images were contrasted across flow territories and Bonferroni-corrected P-values reported.', 'BOLD cerebrovascular reactivity (i.e., long-TE VE-ASL) Z-statistics were similarly sensitive to asymmetric disease (P0.002) regardless of labeling scenario. Cerebral blood flow reactivity correlated significantly with BOLD reactivity (Z-statistic). However, BOLD signal changes did not differ significantly between labeling scenarios (P>0.003) or across territories (P>0.002), indicating BOLD signal changes in response to carbogen offer low sensitivity to lateralizing disease.
Answer: Dual echo VE-ASL can provide simultaneous cerebral blood flow and qualitative BOLD contrast consistent with lateralizing disease severity in patients with asymmetric steno-occlusive disease. The methodological strengths and limitations of composite BOLD and VE-ASL measurements in the clinic are discussed.
Do dual echo vessel-encoded ASL for simultaneous BOLD and CBF reactivity assessment in patients with ischemic cerebrovascular disease?

Context: Preoperative neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) have prognostic value in patients with various operable tumors. The aim of our study was to determine whether NLR and PLR are predictive of survival in thymic carcinoma patients after complete resection.', 'A total of seventy-nine patients who underwent complete resection of thymic carcinoma at our hospital between January 2005 and December 2015 were retrospectively enrolled. Differential leukocyte counts were collected before surgery, and the relationships of NLR, PLR, and other patient clinical variables with survival were estimated by Cox regression analysis and Kaplan-Meier survival analysis.', 'Univariate analysis found that a high level of NLR was associated with lower disease-free survival (DFS) (HR: 3.385, 95% CI: 1.073-10.678, P=0.037) and lower overall survival (OS) (HR: 12.836, 95% CI: 1.615-101.990, P=0.016). The optimal NLR threshold of 4.1 could stratify the patients with high risk of recurrence or metastasis (P=0.026) and death (P=0.006). Meanwhile, the NLR value of >4.1 in those patients was associated with bigger tumor size (P=0.035) and more advanced Masaoka stages (P=0.040) compared with NLR 4.1. However, the PLR and other variables were not significantly associated with survival in thymic carcinoma patients.
Answer: The preoperative NLR of >4.1 was significantly associated with larger tumor size, more advanced Masaoka stages and reduced DFS and OS, but was not an independent predictor of survival in thymic carcinoma patients after complete resection.
Is prognostic value of preoperative neutrophil-lymphocyte ratio superior to platelet-lymphocyte ratio for survival in patients who underwent complete resection of thymic carcinoma?

Context: Relatively little is known about why almost half of young adults in Australia have used cannabis. Because the upwards trend in use of cannabis has been coincident with an increase in marital breakdown, this study examines the relationship between marital status, marital changes, and the onset of cannabis use.', 'Data are from the Mater-University Study of Pregnancy (MUSP), a 21-year prospective study in Brisbane, Australia. The present study is based on the 3008 mothers and their children for whom there were complete follow-up data at 21 years. Outcomes were self-reported cannabis use at age 21 and early onset (before age 15) cannabis use as judged from a retrospective report obtained at 21 years. Analyses were conducted using multivariate binomial and multinomial logistic regression.', 'Change in maternal marital status when the child was aged between 5 and 14 years was significantly associated with increased risk of cannabis use [odds ratio (OR) = 1.7; 95% confidence interval (95% CI) 1.4-2.0 for one or two marital changes and OR = 2.3; 95% CI 1.5-3.4 for three or more marital changes], after adjustment for a range of potential confounders.
Answer: Experience of changes in maternal marital status in mid- to late-childhood is a significant predictor of subsequent and early use of cannabis by the child. This holds true even after allowing for certain possible causes and consequences of marital breakdown.
Are changes in maternal marital status associated with young adults ' cannabis use : evidence from a 21-year follow-up of a birth cohort?