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.

Ex Input:
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\u2009=\u200912; age\u2009=\u200955 +/- 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 (P\u2009≤\u20090.002) 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\u2009>\u20090.003) or across territories (P\u2009>\u20090.002), 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.

Ex Output:
Do dual echo vessel-encoded ASL for simultaneous BOLD and CBF reactivity assessment in patients with ischemic cerebrovascular disease?


Ex Input:
Context: Pedicle subtraction osteotomy (PSO) is one of the surgical options for treating alignment disorders of the fused spine (due to post-surgical fusion or related to arthritis). It enables satisfactory sagittal realignment and improved function due to economic sagittal balance. The aim of this study was to analyze clinical and radiological results of PSO after a minimum follow-up of 2\xa0years and demonstrate the benefit of sub-group analysis as a function of pelvic incidence (PI).', 'A descriptive prospective single center study of 63 patients presenting with spinal global malalignment who underwent correction by PSO. Function was assessed by the Oswestry disability index (ODI), a visual analog scale of lumbar pain (VAS) and a SF-36 questionnaire. Radiographic analyses of pre- and post-operative pelvic-spinal parameters were performed on X-rays obtained by EOS(®) imaging after 3D modeling. Global analysis and analysis of sub-groups as a function of pelvic incidence were performed and the full balance integrated index (FBI) was calculated.', 'this series showed a marked clinical improvement and significant progress of functional scores. Global post-operative radiological analysis showed a significant improvement in all pelvic and spinal parameters. The mean correction obtained after PSO was 31.7°\xa0±\xa08.4°, hence global improvement of lumbar lordosis of 22°. The sagittal vertical angle (SVA) decreased from +9\xa0cm before surgery to +4.3\xa0cm after surgery. Sub-group analysis demonstrated greater improvement in pelvic tilt, sacral slope and spinal parameters of patients with a small or moderate pelvic incidence; all had an FBI index\xa0<10°. Most of the pelvic and spinal parameters of patients with a large pelvic incidence were insufficiently corrected and they had an FBI index\xa0>10°
Answer: PSO is a surgical procedure enabling correction of multiplane rigid spinal deformities that require major sagittal correction. It was seen to be highly effective in patients with a small or moderate pelvic incidence (PI <60°) but was sometimes less effective in patients with large pelvic incidence due to insufficient lordosis correction. Clinical results were highly correlated with the value of the FBI index.

Ex Output:
Are clinical and radiological outcomes of lumbar posterior subtraction osteotomies correlated to pelvic incidence and FBI index : Prospective series of 63 cases?


Ex Input:
Context: To investigate the impact of prophylactic hyperoxic ventilation with Fio2 0.6 on the physiologic limit of acute normovolemic anemia.', 'Prospective, controlled, randomized experimental study.', 'Experimental animal laboratory of a university hospital.', 'Fourteen anesthetized domestic pigs.', 'Animals were randomly ventilated with either Fio2 0.21 (group 0.21, n = 7) or Fio2 0.6 (group 0.6, n = 7), and acute anemia was induced by isovolemic blood-for-hydroxy-ethylstarch (HES) exchange using a 6% HES solution (130/0.4).', 'The blood-for-HES-exchange was continued until a sudden decrease of total body oxygen consumption indicated the onset of oxygen supply dependency (primary end point); the corresponding hemoglobin (Hb) concentration was defined as "critical" (Hb(crit)). Secondary end points were changes in myocardial function, central hemodynamics, oxygen transport, and tissue oxygenation. Compared with room air ventilation (Fio2 0.21), hyperoxic ventilation with Fio2 0.6 enabled a larger blood-for-HES-exchange (139%, 124/156) of circulating blood volume vs. 87% (68/94, p < .05), until Hb(crit) was reached (1.5 g/dL [1.4/2.1] vs. 2.4 g/dL [2.0/2.8], p < .05). At Hb 2.4 g/dL (i.e., Hb(crit) in group 0.21), animals of group 0.6 still presented with superior oxygen transport, tissue oxygenation, and hemodynamic stability. However, hemodynamic and oxygen transport variables were found deteriorated more severely at Hb 1.5 g/dL (i.e., Hb(crit) of group 0.6) compared with group 0.21 at Hb 2.4 g/dL.
Answer: During cell-free volume replacement, hyperoxic ventilation with Fio2 0.6 generates a readily usable plasmatic oxygen reserve and thereby increases the tolerance toward acute normovolemic anemia.

Ex Output:

Does hyperoxic ventilation increase the tolerance of acute normovolemic anemia in anesthetized pigs?