Biomedical subjects

K Lercher

Publications and source records attributed to K Lercher.

3 recordsLinked to original sources

PubMed2001

[Technical errors in the application of Graf's hip sonography method].

AIM: The aim of the study is to point out possible examination errors because of a titled transducer, and to analyse their sources. METHODS: The results obtained by experienced examiners using the correct examination technique were compared to results obtained under defined deviations from the standard. With the use of a computer model the course taken by the ultrasound waves in the neonatal hip was simulated and the sonographic image reconstructed. RESULTS: Twisted as well as tilted positions of the transducer lead to significant errors in alpha, the acetabular roof angle. This is in accordance with the computer model predictions. Caudo-cranially tilted probes lead to false-positive, therapeutically relevant incorrect diagnoses. CONCLUSION: The computer simulation predicts a high degree of accuracy of hip sonography in Graf's technique under standard conditions. The effectiveness of sonographic infant hip screening largely depends on the ability to adhere to the standardized approach, minimizing possible errors. A mechanical transducer guide prevents tilting errors by reducing the degrees of variability in positioning the transducer.

Artifacts↗

PubMed1996

[Experiences with a 3-D ultrasound system in infant hip joints].

AIM: To test the possibilities of 3-dimensional sonography in diagnosing congenital hip dysplasia. METHOD: 128 infant hip joints were examined by 4 investigators with different levels of experience. The Kretz Combison 530 machine additionally equipped with an automatic 5 MgHz transducer and volume box system was employed. RESULTS: The average time to determine the standard plane was 21 seconds. The single standard deviation for alpha values in the 3-dimensional system was 3.0 degrees, compared to 1.37 degrees in the conventional system. Observer experience was not a crucial factor. CONCLUSION: The described 3-dimensional system makes it quicker and simpler to determine the standard plane when evaluating infant hips. The higher standard deviation is possibly caused by the obliquity of the ultrasonic beam. Ossification defects on the acetabular roof are better visualized with this approach than with conventional ultrasound or radiological methods. Even though 3-dimensional ultrasound represents a new approach to infant hips, it seems worthy of rapid development.

Acetabulum↗

PubMed1995

[Use of a dynamic balance for standardized imaging technique in entire roentgen images of the spine of children in the upright position].

INTRODUCTION: Malposture can simulate deformities of the spine in non-standardized X-rays of the spine. MATERIALS AND METHODS: A balancelike positioning device was developed in order to avoid "pseudodeformities" because of the patient's malposture while an X-ray of the spine was being taken. A comparative pilot study (100 patients) was performed and about 3,000 X-rays of the spine were taken routinely using the positioning device. RESULTS: The clinical examination and radiological findings did not agree, a second X-ray was taken using the balancelike positioning device. One-third of those patients had much better findings with the balance, one-third slightly better results, and one-third revealed no significant improvement of the malposture in the X-ray film compared with the initial X-ray without the balance device. DISCUSSION: Comparable X-rays of the spine can only be taken if posture during the procedure is defined and reproducible. "Casual" posture and "standardized" posture differed in more than two-thirds of our comparative pilot study (n = 100). The findings with a balance device were never inferior compared to the X-rays taken without it. CONCLUSION: A simple balancelike positioning device can help to standardize X-rays of the spine when the patient is standing, providing better reproducibility, more accurate prognostic aspects and fewer ionizing hazards.

Adolescent↗