Effect of different quantities of a sugared clear fluid on gastric emptying and residual volume in children: a crossover study using magnetic resonance imaging.

BACKGROUND: Gastric emptying in the first 2 h after 7 ml kg(-1) of sugared clear fluid has recently been investigated in healthy children using magnetic resonance imaging (MRI). This study aims to compare gastric volume and emptying half-life during 1 h after 3 or 7 ml kg(-1) sugared clear fluid intake. METHODS: Fourteen healthy volunteer children aged 11.1 (8.2-12.5) yr were investigated prospectively after administration of 3 and 7 ml kg(-1) diluted raspberry syrup in a randomized order, after overnight fasting (baseline). Gastric content volume (GCV(w)) was assessed with a 1.5 Tesla MRI scanner in a blinded fashion. Data are presented as median (range) and compared using the Wilcoxon test. RESULTS: Baseline GCV(w) was 0.39 (0.04-1.00) and 0.34 (0.07-0.75) before intake of 3 and 7 ml kg(-1) syrup, respectively (P=0.93). GCV(w) was 0.45 (0.04-1.55)/1.33 (0.30-2.60) ml kg(-1) 60 min after ingestion of 3/7 ml kg(-1) syrup (P=0.002). Thus GCV(w) had declined to baseline after 3 ml kg(-1) (P=0.39) but not after 7 ml kg(-1) (P=0.001) within 60 min. T(1/2) was 20 (10-62)/27 (13-43) min (P=0.73) after 3/7 ml kg(-1). CONCLUSION: In healthy volunteer children, residual GCV(w) 1 h after intake of 3 ml kg(-1) syrup is significantly smaller than that after 7 ml kg(-1) and within the range of baseline.

Residual gastric contents volume does not differ following 4 or 6 h fasting after a light breakfast - a magnetic resonance imaging investigation in healthy non-anaesthetised school-age children.

BACKGROUND: While American Society of Anesthesiologists and European Society of Anaesthesiology guidelines recommend 6 h pre-anaesthetic fasting for food and non-clear fluids in children, some institutions allow shorter fasting times of 4 h. Aim of this pilot study was to compare weight-indexed residual gastric contents volumes (GCV(w)) after 4 vs. 6 h after a light breakfast, using magnetic resonance imaging (MRI) in healthy volunteer children not scheduled for anaesthesia. METHODS: Four vs. 6 h (F(4) /F(6)) of food fasting were simulated in a crossover study. After overnight fasting (baseline), each child ingested a light breakfast (cereal flakes, milk products) on two separate days. Additional clear fluid (7 ml/kg raspberry syrup) was given either after 2 (F(4) ) or 4 h (F(6) ), followed by half-hourly MRI acquisition for 2 h. MRI was obtained on a 1.5 Tesla scanner as 5 mm axial images (FIESTA) and volumes were traced manually by one blinded observer. Data are given as median (range) or mean ± standard deviation. RESULTS: Eighteen healthy volunteers aged 9.0 (6.8-12.2) years participated. GCV(w) for F(4) and F(6) at baseline was 0.50 ± 0.27 and 0.76 ± 0.48 ml/kg (P = 0.07), respectively, GCV(w) after 4 and 6 h was 0.72 ± 0.85 and 0.47 ± 0.25 ml/kg (P = 0.88). T(1/2) after syrup intake was 30.8 ± 12.2 and 28.3 ± 5.7 min (P = 0.47) for F(4) and F(6) , respectively. CONCLUSION: Residual gastric contents volumes at a hypothetical anaesthesia start were similar for 4 and 6 h food fasting in healthy volunteer school-age children.

MR imaging findings in patients with secondary intracranial hypertension.

BACKGROUND AND PURPOSE: IH can alter the configuration of anatomic structures of the central nervous system. We determined the sensitivity and specificity of MR imaging to detect these changes in patients with secondary IH. MATERIALS AND METHODS: Patients (n = 36) with IH were prospectively investigated with MR imaging and were matched to 36 controls. MR images were evaluated for elongation and edema of the optic nerves, protrusion of the optic disc, flattening of the posterior sclera, height of the pituitary gland, and width of the optic nerve sheath. On MRV, we recorded venous sinus abnormalities and measured the luminal width of the superior ophthalmic veins. A grading score was introduced to define cranial venous outflow obstruction. RESULTS: Cranial venous outflow obstruction and ONS hydrops were the most valid signs indicating IH with a sensitivity of 94% and 92% and a specificity of 100% and 89%, respectively. Sensitivities and specificities were 56% and 97% for reduced pituitary height, 64% and 78% for flattening of the posterior sclera, 31% and 97% for widening of the superior ophthalmic veins, 33% and 100% for optic disc protrusion, 14% and 100% for optic nerve edema, and 6% and 100% for elongation of the optic nerve. At least 2 MR imaging findings could be demonstrated in each patient but in none of the controls. The number of positive MR imaging findings correlated with CSF pressure (r = 0.62, P = .01). CONCLUSIONS: The combination of cranial and orbital MR imaging and MRV can be highly sensitive and specific in the diagnosis of patients with IH.

MR imaging of the optic nerve sheath in patients with craniospinal hypotension.

BACKGROUND AND PURPOSE: Craniospinal hyper- or hypotension leads to morphologic changes in certain intracranial structures. We tested the hypothesis that the amount of CSF in the ONS visible in MR imaging is reduced in patients with CSH. MATERIALS AND METHODS: Nineteen patients with CSH were prospectively studied. Three readers assessed the width of the peri-optical CSF rim at 4 different anatomic positions by using coronal STIR sequences from a 3T MR imaging scanner. The height of the pituitary gland was also measured. Results were compared with normal values obtained with the same imaging technique. Qualitative signs of CSH also recorded were engorgement of venous sinuses, dural enhancement, subdural effusion, narrow ventricles, and sagging brain. RESULTS: CSF signal intensity surrounding the optic nerves was diminished in at least 2 of the 4 positions used for measurements so that decreased diameters of the ONSs were observed in all patients (sensitivity, 100%; specificity, 97%). The height of the pituitary gland was above normal limits in 12 of 19 patients (sensitivity, 63%; specificity, 97%). Frequencies of qualitative signs of CSH varied from 32% to 81%. CONCLUSIONS: The ISSON in patients with CSH is partially or fully collapsed due to reduced CSF content. In comparison with other anatomic markers, this sign showed the highest sensitivity for the diagnosis of patients with CSH in this study.