Diffusion weighted imaging sequences are now widely available on Magnetic Resonance Imaging (MRI) scanners. Diffusion Tensor Imaging (DTI) of the brain is able to show white matter tracts and is now commonly used in human medicine to study brain anatomy, tumors, structural pathways,. . . The purpose of this study was to show the interest of DTI to reveal the white matter fibers in the dogs' brain. DTI MR Images for this study were obtained with a 3 T system of 4 dogs euthanized for other reasons than neurological disorders. Combined fractional anisotropic (FA) and directional maps were obtained in the first 2 hours after death. The heads were amputated immediately after scanning and stored in 10% formalin until preparation for dissection. An experienced anatomist tracked white matter tracts with clinical relevance using the scanner software. The selected tracts were volume rendered and correlated with gross dissection. Using DTI we were able to track relevant neurological connections, such as the corticospinal tract, the optic and the cerebellar tract. The three dimensional anatomy is better presented using modern visualization techniques. DTI seems to be a valuable tool in order to present clinically relevant white matter tracts to neurological clinicians and researchers. Anat Rec, 296:340-349, 2013. V C 2013 Wiley Periodicals, Inc.Key words: brain; diffusion tensor imaging; dog; anatomy Since a few years, Magnetic Resonance Imaging is a reference technique for imaging the brain in different planes (sagittal, transversal, coronal) and the use of 1,5T to 7T MRI allows more and more accurate and detailed visualization of white matter localization than conventional CT-Scan and X-Ray (Van Thielen et al., 2010). However, an atlas of all the white matter tracts would be particularly useful for providing detailed anatomical data that is not available in studies based on conventional MRI data (Lawes et al., 2008). So we
For patients with CF cystic fibrosis , a dedicated chest CT protocol can replace the two yearly follow-up chest radiographic examinations without major dose penalty and with similar diagnostic quality compared with conventional CT.
Purpose To optimize our standard full-spine radiography with respect to diagnostic quality and dose. Methods A phantom study was performed to establish an optimal posterior-anterior view (PA) full spine protocol having the lowest dose with non-inferior quality compared to standard. We then applied this protocol in 40 pediatric patients (group B). The radiographs were scored on six criteria by a pediatric radiologist and orthopedist and compared to the scores of 40 PA full spine radiographs performed in 2013 with standard protocol (group A). Radiation dose was assessed by dose area product (DAP) and effective dose (E). Statistical analysis included independent samples t test, Mann-Whitney U test and intra-class correlation coefficient (ICC). Results An optimized protocol was defined (0.2 mm Cu filter, 0.87 relative exposure, with grid). Mean age was 13.3 ± 1.6 years for group A and 13.4 ± 1.7 years for group B. For group B, the mean DAP was 47.0 µGy m 2 with an E of 0.13 mSv. For group A, the mean DAP was 85.3 µGy m 2 with an E of 0.24 mSv. This represents a dose reduction of 45%. Mean image quality scores for group A (27.9 ± 2.4) and group B (28.1 ± 2.3) were similar (p = 0.612). Interobserver agreement was observed to be excellent (ICC 0.92). Conclusion This study demonstrates that a low-dose full-spine radiograph can be performed in patients with idiopathic scoliosis without loss of image quality.Graphical abstract These slides can be retrieved under Electronic Supplementary Material.
Key points1. RadiaƟon safety is an important aspect, in parƟcular when imaging children.2. Phantom studies can help to understand the impact of technical radiography parameters on image quality and dose.3. RadiaƟon dose could be dramaƟcally decreased (45%) to 0.13 mSv.
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