[Assessment of skeletal age using a new ultrasound method]. / Abschätzung des Knochenalters mit einer neuen Ultraschallmethode.

PURPOSE: Determination of skeletal development in children is important. The most used evaluation method is to study left hand X-ray based on the standards depicted by Greulich and Pyle. The aim of our study was to compare the accuracy of a new sonographically based method with the standard method. MATERIAL AND METHODS: 160 consecutive evaluated children and adolescents (77 male, 83 female) who received a X-ray of the left hand were evaluated. Ultrasound examination of the same hand was performed on the same day using the BonAge system (Sunlight Medical Ltd., Israel). This system evaluates the relationship between the velocity of the wave (speed of sound) passing thorough the distal radial and ulna epiphysis and growth, using gender- and ethnicity-based algorithms. Three experienced investigators (U1-U3) analysed the X-ray and assigned bone age scores based on the Greulich and Pyle atlas (G and P). The investigators were blinded to the calendary age (CA) of the patient and also for the BonAge result. Correlation between BonAge system results and G and P was performed using SPSS 12.0.1. RESULTS: In 152 patients BonAge measurement could be performed successfully. The correlation between the three investigators using the G and P method was between 0.977 and 0.980; correlation between the BonAge system and the investigators (U1-U3) was 0.902 and 0.920. The paired t-test showed no significant differences between the BonAge system and the three investigators and also for the comparison between U1 and U2. There were significant differences between U1 vs. U3 and U2 vs. U3 (p < 0.05). DISCUSSION: The BonAge device demonstrates the ability to produce an sufficient assessment of bone age using an ultrasound method. The results are correlated with conventional skeletal age evaluation using the G and P method. Advantages of the ultrasound device are objectivity, lack of ionizing radiation, and easy accessibility. In the case of first investigation X-ray is necessary to look for dissociated skeletal age, dysplasia, and mineralisation.

Observation of a 1H double quantum filtered signal of water in biological tissues.

The observation of a 1H double quantum filtered (DQF) NMR signal of water in bovine sciatic nerve, bovine articular cartilage, rat tail tendon, and rat brain is reported. The origin of this signal in rat tail tendon was found to be a result of residual dipolar interaction between water protons and macromolecular protons. The dependence of the width of the 1H DQF spectra on the orientation indicated that in rat tail tendon the effective director of the residual dipolar interaction is parallel to the collagen fibers. 1H DQF NMR may be applied in imaging where the contrast obtained is related to the degree of order in the tissue.

In vivo (1)H double quantum filtered MRI of the human wrist and ankle.

Proton double quantum filtered (DQF) NMR imaging was applied in vivo to the human wrist and ankle with a clinical 1.5 T MR scanner. Water molecules having anisotropic motion were detected from tendons and ligaments. Images of Achilles tendon were obtained for a voxel size of 1.25 x 1.25 x 20 mm with three values of TR = 1.0, 0.5, and 0.2 sec, resulting in total acquisitions time of 17, 8.5, and 3.4 mins, respectively. Some degradation of the signal-to-noise ratio was observed at the shortest TR value and the contrast was significantly reduced due to SQ coherence leakage. The in vivo DQF images showed structure within the tendon that is otherwise not visible by conventional gradient-recalled echo (GRE) methods. Published 2000 Wiley-Liss, Inc.

Slice-selective proton double quantum filtered MRI of joint connective tissues.

1H double quantum filtered (DQF) imaging has been shown to highlight tendons. In this work the DQF magnetic resonance imaging pulse sequence is extended to include slice selection. The short transverse relaxation time of the 1H nuclear magnetic resonance in connective tissues, presents a stringent demand on the application of gradients and soft radiofrequency pulse lengths needed for slice selection. In the present work a slice selection pulse sequence is implemented by postponing the application of the slice refocusing gradient to the period after the last pulse just before the acquisition. Slice-selective DQF images of rat lower leg and knee are given to demonstrate the efficacy of the technique.

Proton double-quantum filtered MRI--a new method for imaging ordered tissues.

The imaging of connective tissues such as cartilage and tendons using standard MRI techniques is hampered by their low signal relative to the surrounding tissues. 1H double-quantum filtered (DQF) MRI is an imaging method that detects molecules associated with ordered structures, while the signal from isotropic fluids is filtered out, thus creating a new type of contrast. The technique is demonstrated on an intact rat tail, where the image of the tendons is highlighted. Although the signal-to-noise ratio is inferior to that in gradient-echo MRI, the contrast between the tendons and the surrounding tissues is significantly better in the DQF MRI. It is demonstrated how, by adjusting the parameters of the DQF imaging pulse sequence, one can modify the contrast and enhance the images of specific compartments within an organ. A comparison with 2H DQF imaging of the same tissue is also given.

1H double-quantum-filtered MR imaging as a new tool for assessment of healing of the ruptured Achilles tendon.

1H double-quantum-filtered magnetic resonance imaging (DQF MRI) was applied to monitor the healing process of the Achilles tendons in rabbits after tenotomy. DQF MRI provides a new contrast, which is based on the non-zero average of the dipolar interaction caused by anisotropic motion of water molecules, determined mainly by their interaction with the ordered collagen fibers. Tissues are characterized by the dependence of their DQF signal on the DQ creation time, tau. With the use of DQF MRI, higher tissue contrast is obtained between tendon, bone, skin, and muscle. The tendons, which give weak signals in standard MRI techniques, are highlighted in the (1)H DQF image. The image changed dramatically during the healing process of the injured Achilles tendon. These changes matched the phases of the healing process. By using a tau-weighted contrast, the DQF images indicate the part of tendon that has not completely healed, even after the conventional MRI appeared normal. Magn Reson Med 42:884-889, 1999.