Clinical Application Of Spiral CT 3D On Lumbar Spondylolysis

[Object] To evaluate 3D(SSD, MIP, VRT) and multiplannar reconstruction (MPR) with spiral CT in the diagnosis of lumbar spondylolysis.[Materials and Methods] Sixteen patients with spondylolysis (9 males and 7females) were performed multi-slices CT with axial volume scans, and all of the axial images were reconstructed with surface shade display(SSD) , multiplanar reformation(MPR) and maximum intensity projection(MIP). The images were retrospectively analyzed.[Result] MIP Well displayed 38 sites of lumbar spondylolysis in 16 cases, while SSD showed vertebal olisthy clearly although it had limitation in demonstrating spondylolysis and lesions within spinal canal. SSD combining anatomic plane cut technic ofcan significantly improve display rate to smaller SS. MPR including sagittal reconstruction, coronal reconstruction, oblique reconstruction, curved-planar reconstruction (CPR). Every windows techic can respectively dispiay different tissues, Lesions were accurately measured in MPR images. MIP images with multi-angle projection technique and improvement of cut technique can stereoscopicallydisplay all lesions.[Conclusion] Broken ala sign,broken handle sign broken necksign and brokenring sign are special CT appearances of lumbar spine spondylolysis . Spiral CT 3D together with MPR plays an important role in detecting spondylolysis. A combination of axial images with MPR , MIP and SSD provides valuable diagnostic and anatomic information helpful for theclinician to adopt optimal management.