instruction:
In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
question:
Context: To examine peripheral nerve stimulation (PNS) thresholds for normal human subjects in magnetic resonance imaging (MRI) gradient coils, and determine if observed thresholds could be predicted based on gross physiologic measurements.', 'PNS thresholds for 21 healthy normal subjects were measured using a whole-body gradient coil. Subjects were exposed to a trapezoidal echo-planar imaging (EPI) gradient waveform and the total change in gradient strength (DeltaG) required to cause PNS as a function of the duration of the gradient switching time (tau) were measured. Correlation coefficients and corresponding P values were calculated for the PNS threshold measurements against simple physiologic measurements taken of the subjects, including weight, height, girth, and average body fat percentage, in order to determine if there were any easily observable dependencies.', 'No convincing correlations between threshold parameters and gross physiologic measurements were observed.\Question: Do simple anatomical measurements correlate significantly to individual peripheral nerve stimulation thresholds as measured in MRI gradient coils?
answer:
These results suggest it is unlikely that a simple physiologic measurement of subject anatomy can be used to guide the operation of MRI scanners in a subject-specific manner in order to increase gradient system performance while avoiding PNS.


question:
Context: Impaired neurodevelopmental outcome represents a major morbidity for survivors of infant heart surgery for congenital heart defects. Previous studies in these neonates have reported preoperative microcephaly, periventricular leukomalacia, and other findings. The hypothesis of this study is that preoperative cerebral blood flow is substantially diminished and might relate to preoperative neurologic conditions.', 'Preoperative brain magnetic resonance imaging was performed. Cerebral blood flow measurements in infants with congenital heart defects were obtained by using a novel noninvasive magnetic resonance imaging technique, pulsed arterial spin-label perfusion magnetic resonance imaging. Cerebral blood flow was measured before the operation under standard ventilation and repeated after increased carbon dioxide.', 'A total of 25 term infants were studied. The average age at the time of the operation was 4.4 +/- 4.6 days. Congenital heart defects varied widely. Microcephaly occurred in 24% (6/25). Baseline cerebral blood flow was 19.7 +/- 9.2 mL . 100 g -1 . min -1 (8.0-42.2 mL . 100 g -1 . min -1 ). Five patients had cerebral blood flow measurements of less than 10 mL . 100 g -1 . min -1 . Mean hypercarbic cerebral blood flow increased to 40.1 +/- 20.3 mL . 100 g -1 . min -1 (11.4-94.0 mL . 100 g -1 . min -1 , P < .001). Pairwise analyses found that low hemoglobin levels were associated with higher baseline cerebral blood flow values ( P = .04). Periventricular leukomalacia occurred in 28% (7/25) and was associated with decreased baseline cerebral blood flow values ( P = .05) and a smaller change in cerebral blood flow with hypercarbia ( P = .003).\Question: Is preoperative cerebral blood flow diminished in neonates with severe congenital heart defects?
answer:
Structural brain abnormalities are common in these neonates before surgical intervention. Preoperative cerebral blood flow for this cohort was low and drastically reduced in some patients. Low cerebral blood flow values were associated with periventricular leukomalacia. Carbon dioxide reactivity was preserved but might be compromised by some aspects of the cardiac anatomy. The full spectrum of cerebral blood flow measurements with this technique in congenital heart defects and their long-term significance require continued investigation.


question:
Context: Anorectal manometry provides objective information about anorectal function, but its results depend on the examiner's skill, the type of equipment, and subject characteristics like age or gender. This single institution, prospective study was performed to investigate the effect of gender and age on the results of anorectal manometry.", 'All included subjects completed a questionnaire to assess their bowel function. The survey included 13 validated questions (eight on constipation and five on incontinence) and was used to exclude subjects with pathological constipation or incontinence. Subjects with normal bowel function underwent anorectal manometry to measure anal sphincter length (ASL), maximum resting pressure (MRP), and maximum squeeze pressure (MSP), and the results were compared by gender and age.', 'The mean age of the 154 participants (94 male and 60 female) was 59.1 years. ASL was greater in men (4.23 vs. 3.85 cm, p\u2009<\u20090.001). MRP was not significantly different according to gender (p\u2009=\u20090.93), but MSP was higher in men (190.18 vs. 116.49 mmHg, p\u2009<\u20090.001). ASL did not correlate with age (p\u2009=\u20090.707). MRP was inversely related to age in both men (R (2)\u2009=\u20090.152, p\u2009<\u20090.001) and women (R (2)\u2009=\u20090.282, p\u2009<\u20090.001), and MSP only in women (R (2)\u2009=\u20090.210, p\u2009<\u20090.001).\Question: Are anorectal manometric parameters influenced by gender and age in subjects with normal bowel function?
answer:

Anorectal manometric parameters are influenced by gender and age. This should be taken into consideration when interpreting manometric readings in a clinical setting.