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Biomedical subjects

Rachel Rosen

Publications and source records attributed to Rachel Rosen.

7 recordsLinked to original sources
PubMed2006

The sensitivity of multichannel intraluminal impedance and the pH probe in the evaluation of gastroesophageal reflux in children.

BACKGROUND & AIMS: Multichannel intraluminal impedance (MII) has been incorporated into gastroesophageal reflux evaluations in children despite a lack of evidence comparing it to the gold standard pH probe. The aim of this study was to compare these two technologies. METHODS: Twenty-five consecutive, untreated children undergoing pH-MII recording were studied. Sensitivities for the pH probe and MII were defined as: (acid+pH-only episodes)/(acid+non-acid+pH-only episodes) and (acid+non-acid episodes)/(acid+non-acid+pH-only episodes), respectively. Sensitivities were compared using paired t testing. After the analysis was performed, the pH-MII tracings of 25 age-matched children taking acid suppression therapy were compared and sensitivity calculations were performed. RESULTS: In untreated patients, 1845 reflux episodes were detected, and 1702 were detected in treated patients. The mean sensitivities of pH probe and MII in untreated patients were 80.6 +/- 18.2% and 76.1 +/- 13.5%, respectively (P = .41). The mean sensitivities of pH probe and MII in treated patients were 47.2 +/- 36.0% and 80.3 +/- 21.1%, respectively (P = .005). Twenty-five percent of reflux episodes were pH-only episodes. There were no differences in the mean number of acid or non-acid reflux episodes in patients with normal and abnormal pH probe studies. Instead, there were significantly more pH-only episodes in patients with abnormal probe studies. CONCLUSIONS: The sensitivity of MII equals that of the pH probe in untreated patients but is superior to the pH probe in treated patients. pH-only episodes are numerous in pediatrics and should be included in pH-MII analyses.

Child↗
PubMed2006

High-resolution ab initio three-dimensional x-ray diffraction microscopy.

Coherent x-ray diffraction microscopy is a method of imaging nonperiodic isolated objects at resolutions limited, in principle, by only the wavelength and largest scattering angles recorded. We demonstrate x-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the three-dimensional diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a nonperiodic object. We also construct two-dimensional images of thick objects with greatly increased depth of focus (without loss of transverse spatial resolution). These methods can be used to image biological and materials science samples at high resolution with x-ray undulator radiation and establishes the techniques to be used in atomic-resolution ultrafast imaging at x-ray free-electron laser sources.

Algorithms↗
PubMed2004

Incidence of spinal cord lesions in patients with intractable constipation.

Abstract Spinal magnetic resonance imaging of children with intractable constipation was reviewed. Nine percent of patients had spinal cord abnormalities. Tethered cord was the most common lesion in 75% of patients. Magnetic resonance imaging is a useful tool to evaluate children with intractable constipation.

Child, Preschool↗
PubMed2004

The importance of multichannel intraluminal impedance in the evaluation of children with persistent respiratory symptoms.

OBJECTIVES: Previous evidence suggests an association between gastroesophageal reflux disease and chronic respiratory disease in children. Despite antisecretory antacid therapy, respiratory symptoms often persist supporting a role for nonacid reflux. The aim of this study was to determine whether nonacid reflux occurs in children with chronic respiratory disease. METHODS: Twenty-eight children (mean age: 6.5 +/- 5.6 yr) with persistent respiratory symptoms on antacid medications underwent 24 h pH/multichannel intraluminal impedance (pH/MII) recording. The symptom index (SI) and the symptom sensitivity index (SSI) were calculated for each patient. Logistic regression was performed to determine which reflux characteristics were associated with a high degree of symptom correlation present during the occurrence of symptoms. RESULTS: A total of 1,822 reflux episodes were detected by pH/MII, 45% of which were nonacidic. The mean SI increased using pH/MII (35.7 +/- 28.5) compared to pH probe alone (14.6 +/- 18.9; p= 0.002); no differences in the mean SSI using pH/MII compared to pH probe alone were identified. Significantly more patients had a positive SI using pH/MII than pH probe alone (p= 0.035); there was no difference in the number of patients with a positive SSI using pH/MII compared to pH probe alone. Multivariate analysis revealed that symptoms occurred more frequently when the reflux was nonacidic, mixed, and full column. Also, younger children were more likely to have the simultaneous occurrence of symptoms and reflux. CONCLUSIONS: Nonacid reflux may be an important predictor of respiratory symptoms. pH/MII provided important information in the evaluation of children with intractable respiratory symptoms.

Adolescent↗