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R R van Rijn

Publications and source records attributed to R R van Rijn.

27 records · Page 2Linked to original sources
PubMed2000

Radiographic absorptiometry of the middle phalanx (digit II) in a Caucasian pediatric population: normative data.

The availability of improved therapies for children with diseases affecting bone growth and/or metabolism has caused increased interest in bone mineral density (BMD) assessment. The purpose of this study was to determine normal values for phalangeal radiographic absorptiometry (RA) in a Caucasian pediatric population. Five hundred and seventy-two healthy Caucasian children and adolescents (aged 5-19 years) were enrolled in this study. For RA one posteroanterior exposure of the left hand and one lateral exposure of the left index finger were taken. All films were analyzed, yielding BMD (mg Al/mm3) values for two phalangeal sites: one at the proximal quarter of the phalangeal length (BMD25%) and the second at the midpoint of the phalangeal length (BMD50%). Also skeletal age (SA) was assessed, as data normalized for SA can be used in populations which show a dissociation between SA and calendar age. We found that the BMD25% was significantly higher in girls than in boys for the SA group 11-14 years. The BMD50% was significantly higher in girls than in boys for the SA group 11-15 years. Our data show that BMD25% remains fairly constant until the SA of 12.0 years in boys and 10.1 years in girls; after these skeletal ages BMD shows a sharp increase. The same applies to BMD50%, which remains fairly constant until the SA of 12.4 years in boys and 10.7 years in girls. In this paper we present normative data for RA in a pediatric population. These data normalized for skeletal age could be implemented in a clinical setting.

Adolescent↗
PubMed2000

Normal values for tibial quantitative ultrasonometry in caucasian children and adolescents (aged 6 to 19 years).

Bone densitometry in children is a relatively new topic of interest within the field of osteoporosis. Bone densitometry techniques using an X-ray source have the disadvantage of radiation exposure. Also on some systems, motion artifacts are caused by long scan times. Tibial quantitative ultrasonometry (QUS) is ideally suited for children as it is radiation free and the interactive measurement provides real-time quality control. In this prospective study, we present data from 596 healthy children-309 girls, mean age 12.9 years (range 6.1-19.9), and 287 boys, mean age 12.3 years (range 6.1-19.6) from Rotterdam, The Netherlands. For all subjects, a short questionnaire regarding overall health was completed. To assess skeletal age, an X-ray of the left hand was taken and tibial QUS of the right tibia was performed using the SoundScan Compact. A statistically significant correlation was found between age and speed of sound (SOS)-r(2)(boys) = 0.52 and r(2)(girls) = 0.63 (both P < 0.001) and between skeletal age and SOS-r(2)(boys) = 0.56 and r(2)(girls) = 0. 63 (both P < 0.001). In boys, significant increase of mean SOS is seen between Tanner stages II and III and between IV and V. In girls there is a significant increase of mean SOS among all Tanner stages, except stages II and III. This is the first study to present normative tibial QUS data for Caucasian children and adolescents. In this study, normative data relative to skeletal age are also provided, facilitating the implementation of this technique in children with growth disorders showing dissociation between calendar and skeletal age.

Adolescent↗
PubMed2000

Tibial quantitative ultrasound versus whole-body and lumbar spine DXA in a Dutch pediatric and adolescent population.

RATIONALE AND OBJECTIVES: To understand normal bone development, studies in healthy children and adolescents are important. To assess the applicability of tibial quantitative ultrasound measurements (QUS) in children, we performed a study that compared dual-energy x-ray absorptiometry (DXA) of the lumbar spine and whole body with tibial QUS. METHODS: For this study we recruited 146 Dutch children and adolescents, 58 boys (median age, 14.1 years; range, 7.6-23.4 years) and 88 girls (median age, 18.0 years; range, 7.6-23.5 years). Tanner stage, weight, and height were assessed for all participants. Bone mineral density (BMD; g x cm(-2)) of the whole body and lumbar spine (L2-L4) and bone mineral apparent density (BMAD) of the lumbar spine (g x cm(-3)) were assessed by using the Lunar DPXL. For tibial QUS, the Soundscan compact system was used. RESULTS: Both lumbar as well as whole-body BMD showed a strong, significant correlation with tibial QUS in boys and girls: rtotal body boys = 0.81, rtotal body girls = 0.77, rlumbar spine boys = 0.79, and rlumbar spine girls = 0.72. Lumbar spine BMAD also showed significant correlations with tibial QUS: rboys= 0.63 and rgirls = 0.63 (for all correlations, P < 0.001). CONCLUSIONS: Our study showing strong, significant correlations between DXA and tibial QUS measurements suggests that tibial QUS is a technique that may be applicable in children and adolescents.

Absorptiometry, Photon↗
PubMed1999

Evaluation of short-term precision for tibial ultrasonometry.

Tibial quantitative ultrasonometry is a relatively novel technique in the field of bone sonometry, an emerging alternative to bone densitometry. The implementation of this technique in a pediatric population could prove valuable from a clinical as well as a research viewpoint. In clinical practice it is necessary to know the precision of this technique and the possible influence on measurements before implementation. This study presents the precision in a Caucasian pediatric population and the influence of measurement site, dexterity, brand of coupling gel, and temperature of coupling gel. To assess intra- and interobserver variance duplicate measurements, with repositioning, ultrasonometry was performed in 10 children over a short period of time. The observers were blinded for the results of the other observer and after each measurement the skin markings were removed. Intraobserver variance for operator one (MHL) and for observer two (SFGR) was CV 0.43%. The interobserver variance was CV 0.61%. Left midtibial and right midtibial speed of sound (SOS) measurements showed no significant differences. There were, however, significant differences in both boys and girls between right proximal versus right midtibial, right midtibial versus right distal, and right proximal versus right distal (for all P < 0.001). One-way analysis of variance (ANOVA) showed that neither the use of different coupling gels nor an increase in gel temperature had a significant influence on measurements. The results of our study show that tibial quantitative ultrasonography (QUS) is a highly reproducible technique in a Caucasian pediatric population.

Adolescent↗
PubMed1998

Vertebral dimensions: influence of X-ray technique and patient size on measurements.

In this study a new reference value, "corrected vertebral dimension," is presented for vertebral height measurements. Of 68 females (age 18-88 years; mean 44.2 years) and 40 males (age 16-81 years; mean 55 years) the projected vertebral dimensions (T4-L5) were measured on lateral radiographs. In addition to this, the vertebra-to-film distances (VFD) were measured and a fixed focus-to-film distance (FFD) was used during the study. Corrected dimensions of the thoracic and lumbar vertebrae (T4-L5) were calculated using the FFD and VFD. These corrected dimensions were then used to recalculate projected vertebral dimensions at different focus-to-film distances. The applied geometric corrections were verified in a phantom study representing an in vitro situation. The results indicate that studies using different X-ray techniques for making lateral radiographs of the spine can become comparable when using corrected vertebral dimensions.

Adolescent↗
PubMed1997

Seven-year experience with a 'quarantine and isolation unit' for patients with burns. A retrospective analysis.

In the burns unit of the Red Cross Hospital, Beverwijk. The Netherlands we performed a retrospective analysis to evaluate whether the spread of multi-resistant micro-organisms (MRMO) in burn victims with a high risk of contamination can be prevented by isolation in a quarantine and isolation unit (QIU). We analysed 1006 patients who where consecutively admitted to the burns unit between 26-03-1985 and 31-12-1992. The age TBSA, and the bacteriological status of all patients were recorded. With regard to the stay in the QIU we recorded the actual number of days between the accident and the time of admission, the duration of the stay, and the therapy given. Of 1006 patients, 72 met the criteria of the Dutch Health Inspectorate for classification as high risk of MRMO contamination. Sixty-one of these 72 patients were treated in the QIU. The mean duration of stay in the QIU was 8.2 days, admission was at 10.2 days postburn, and 20 patients did harbour MRMO. There was no report of any cross-contamination. Since the QIU became operational there have been no outbreaks of MRMO in our burns unit. In our opinion this shows the effectiveness of the QIU.

Adolescent↗
PubMed1997

Correlating sheet plastinated slices, computed tomography images and magnetic resonance images of the pelvic girdle: a teaching tool.

Sheet plastination is currently used to produce anatomical slices of different body structures, allowing one to study and teach their topography in an anatomically correct state. Correlation with computed tomography (CT) and magnetic resonance imaging (MRI) techniques gives more insight into their anatomy. Using two female cadaver pelvises CT and MRI were performed. One pelvis was used to prepare 2-mm-thick coronal plastinated slices according to the technique described by von Hagens. We found a good overall correlation between plastinated slices, CT and MRI images. This combined approach provides a unique anatomical insight and is a valuable addition to other teaching tools used by medical students, radiologists and anatomists.

Anatomy, Cross-Sectional↗