Surg Radiol Anat (2010) 32:581–585 DOI 10.1007/s00276-009-0601-0 123 ORIGINAL ARTICLE Comparison of spinal anatomy between 3-Tesla MRI and CT-myelography under healthy and pathological conditions Astrid Ellen Grams · Jens Gempt · Annette Förschler Received: 11 October 2009 / Accepted: 16 November 2009 / Published online: 6 December 2009  Springer-Verlag 2009 Abstract Purpose In many centres both MRI and CT-myelography are performed for treatment planning of degenerative spine disease. More and more centres acquire 3-Tesla MRI scan- ners in which some artefacts, which lead to diYculties in image evaluation, are more pronounced than at 1.5 Tesla. Aim of this study was to compare spinal physiological and pathological anatomy between 3-Tesla MRI and CT-mye- lography and to review current imaging standards. Methods In 47 spinal segments commonly used 3-Tesla T2-weighted sequences and CT-myelography studies were evaluated retrospectively. Spinal canal, neural foraminal, spinal cord and disc protrusion diameters were measured. Results The spinal canal was found to be 10% tighter with the utilized MRI sequences, in comparison to CT-M and foraminal diameters were found to be 19.7% tighter in MRI. This was more pronounced in narrowed than in healthy segments. Spinal cord size and size of disc protru- sions displayed no signiWcant diVerence between MRI and CT-myelography. Conclusions The main advantage of CT-myelography, in comparison to 3-Tesla MRI, is the reliable information about the bony structures. Soft tissues like the spinal cord or disc protrusions were visualised equivalently with both modalities concerning diameters. Keywords 3 Tesla · CT · Myelography · Spinal stenosis · Foraminal stenosis Introduction In spinal imaging degenerative changes such as bony steno- sis or disc protrusions are frequently observed even in asymptomatic patients [12]. Therefore, it remains a chal- lenge to establish diagnosis of clinically relevant nerve root compression or spinal canal stenosis and to enable correct surgical planning, especially in patients who suVer from multisegmental or multicausal degenerative changes or patients who have undergone previous spinal surgery [5]. With computed tomography (CT) imaging bony struc- tures can be visualised reliably; in this regard it is com- monly accepted as the “gold standard”. CT imaging after intrathecal injection of an iodine contrast agent, known as CT-myelography (CT-M), provides additional information concerning the eVects of bony structures or soft tissues on the dural sac and the proximal spinal nerve roots [6]. How- ever, CT-M is an invasive examination which comprehends several possible adverse events, such as meningitis, CSF leaks or nerve root injury. Magnetic resonance imaging (MRI) is believed as the “gold standard” in the visualisation of soft tissues, such as disc protrusions, hypertrophy of the ligamentum Xavum, or scar tissue, which may display reasons for spinal or forami- nal stenosis. However, the spatial relations of bony struc- tures are often overestimated in MRI [2, 8]. In recent years many centres introduced 3-Tesla scan- ners for use in clinical routine instead if 1.5-Tesla scanners. A. E. Grams (&) Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstr. 55, 45122 Essen, Germany e-mail: astrid.grams@uk-essen.de J. Gempt Department of Neurosurgery, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany A. Förschler Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany