Biomedical subjects

Wael Shabana

Publications and source records attributed to Wael Shabana.

4 recordsLinked to original sources

PubMed2003

Meniscal tears: comparison of half-Fourier technique and conventional MR imaging.

PURPOSE: To determine whether half-Fourier MR image acquisition technique can provide similar information to that of conventional MR acquisition technique for evaluation of meniscal tears. MATERIALS AND METHODS: We studied 101 menisci in 52 patients who were referred for evaluation of meniscal tears. Sagittal MR images of the knee were obtained for all patients by using proton density and T2-weighted SE sequences on a 1-T clinical system. The half-Fourier technique and conventional technique were used for all patients. All other imaging parameters were identical for both sequences (TR/TE=2400/20,70; 3 mm slice thickness; 200 x 256 matrix; field of view, 200; one signal acquired). Both sets of images were filmed with standard window and level settings. Images were randomised and interpreted independently by two radiologists for the presence of meniscal tears. Images were also subjectively assessed for image quality using a five-point grading scale. RESULTS: On half-Fourier images, Reader 1 interpreted 23 menisci as torn, compared to 28 for Reader 2. On conventional images, Reader 1 interpreted 24 menisci as torn, compared to 26 for Reader 2. Agreement between interpretation of the conventional and that of the half-Fourier images was 99% for Reader 1, and 98% for Reader 2. Agreement between readers for the half-Fourier images was 95%, and for the conventional images 96%. No statistically significant difference was found in the subjective evaluation of image quality between the conventional and half-Fourier images. CONCLUSION: The half-Fourier acquisition technique compares favourably with the conventional technique for the evaluation of meniscal tears.

Adolescent↗

PubMed2003

Reducing inter-observer variation in thyroid volume calculation using a new formula and technique.

OBJECTIVE: Ultrasound (US) measurement of thyroid volume is used in diagnosis and follow-up of patients with thyroid disease. We assessed a new formula and technique for thyroid volume calculation, based on an automatically continuous trace transverse surface area (aTSA) calculation, to ascertain where this technique could reduce inter-observer variation. METHODS: Three observers with a different level of US expertise, using a 12-5 MHz linear transducer, examined 25 volunteers. Inter-observer variations were calculated for diameter measurements and for the thyroid lobe volume calculations using the single factor ANOVA method. RESULTS: Using the new technique and formula, no statistically significant differences existed, in contradistinction to using the classical formula for an ellipsoid (P=0.02). CONCLUSION: When thyroid volume measurements are required, we recommend using a new method of thyroid volume calculation based on the use of an automatically calculated continuous trace aTSA measurement to avoid significant inter-observer variation in calculation of thyroid lobe volumes.

Adult↗

PubMed2002

Study of pediatric brain development using magnetic resonance imaging of anisotropic diffusion.

The properties of water diffusion in human brain tissue can be characterized by diffusion tensors computed from diffusion weighted magnetic resonance images. Since these properties are strongly determined by the structural and geometrical characteristics of the tissue, the maturation process of white matter and gray matter tissue can be expected to be reflected in these images and derived tensor quantities. The purpose of this work was therefore to study the development of pediatric brain in terms of changes occurring in the observed diffusion behavior. Echo planar diffusion tensor imaging was performed on 22 (10 females and 12 males) full term newborn and infant patients, diagnosed in retrospect as neurologically healthy. The subjects were subdivided in three age categories. A number of quantities based on the diffusion images were calculated for each tissue type and age category, and the ability of these quantities to provide sensitive and consistent information about the tissue differences and evolution was evaluated. The results clearly illustrate that the rotationally invariant quantities (e.g., the highest diffusivity, anisotropy ratio and volume ratio) are superior to the rotationally variant ones (e.g., ADCs measured along the three axes of the magnet) often used in the clinic. On the basis of the anisotropy ratio and the volume ratio indices, a correlation between the white matter maturation and the evolution of the diffusion anisotropy could be established. The same quantities did not exhibit any age dependence for the gray matter tissues.

Anisotropy↗

PubMed2002

Sonography of the medial and lateral tendons and ligaments of the knee: the use of bony landmarks as an easy method for identification.

OBJECTIVE: Our purpose was to describe the use of bony landmarks in the evaluation of the medial and lateral ligaments and tendons of the knee on sonography and to evaluate the value of this approach in healthy volunteers. MATERIALS AND METHODS: Anatomic slices obtained in cadaveric specimens were inspected for the presence of bony landmarks on the medial and lateral aspects of the knee. Then sonography was performed on 40 knees of 20 healthy volunteers by two musculoskeletal radiologists who independently rated the visualization of bony landmarks and adjacent ligaments and tendons on a 5-point grading scale. RESULTS: Bony landmarks on the lateral aspect of the knee include Gerdy's tubercle on the tibia and the sulcus for the popliteal tendon on the femur. Landmarks on the medial aspect of the knee include the medial epicondyle on the femur and the sulcus for the semimembranosus tendon on the tibia. Visualization of all landmarks was rated in the good to excellent range, and agreement between observers ranged from 92.5% to 100%. CONCLUSION: Bony landmarks can be identified in healthy adults on the medial and lateral aspects of the knee and may serve as reference points for identification of most medial and lateral tendons and ligaments.

Adult↗