Dr. James Haug D.O. Dr. Chad Christensen D.O. Dr. Jonathan Kini M.D. Dr. John Ritter M.D. San Antonio Military Medical Center Fort Sam Houston, TX Abbreviated MR Protocol To Exclude Cauda Equina Syndrome in the Emergency Setting

The purpose of this presentation is to: 1. Describe common symptoms associated with cauda equina syndrome (CES). 2. Review standard vs. rapid MR protocol to exclude CES. 3. Illustrate the benefits of implementing rapid MR protocol in the emergency setting. Learning Objectives

Cauda equina syndrome (CES) is caused by acute stenosis of the lumbar spinal canal leading to compression of the neural elements below the L1 level. CES is a relatively uncommon, yet serious condition that has potentially devastating consequences if prompt diagnosis is not made. Symptoms vary widely and include saddle anesthesia and urinary, bowel, and/or sexual dysfunction. Introduction/Background Introduction Rapid Protocol Methods Results Discussion Conclusion

Introduction Rapid Protocol Methods Results Discussion Introduction/Background Conclusion

We propose that a rapid MR protocol, which includes the thoracic spine, can more quickly and effectively screen for CES and identify mimickers not otherwise detected on standard lumbar MR imaging. Introduction/Background Introduction Rapid Protocol Methods Results Discussion Conclusion

o severe low back pain o motor weakness/sensory loss o saddle anesthesia o bladder incontinence o bowel incontinence o recent onset of sexual dysfunction o lower extremity hyporeflexia Symptoms of Cauda Equina Syndrome

Causes of Cauda Equina Syndrome More common: o Lumbosacral disc herniation (most common) o Trauma/Fracture o Hemorrhage (epidural hematoma) o Infection (discitis/osteomyelitis, epidural abscess) o Tumor (extradural, intradural extramedullary) Less common: o Cord ischemia o Inflammatory/Demyelinating o Vascular abnormalities (e.g. spinal AVMs)

An abbreviated MR protocol taking less than 10 minutes was implemented utilizing sagittal 3D T2 SPACE imaging of both the thoracic and lumbar spine to improve provision of care. An additional sagittal FSE T2 sequence of the thoracic spine through the level of the conus was also included. Introduction Rapid Protocol Methods Results Discussion Materials and Methods Conclusion

Emergency room patients presenting with symptoms concerning for CES were imaged with this protocol. Patients with a history of malignancy or recent trauma were excluded and underwent standard imaging. A post implementation evaluation of the medical treatment of these patients was subsequently conducted. Materials and Methods Introduction Rapid Protocol Methods Results Discussion Conclusion

Rapid MR Cauda Equina Protocol Rapid Protocol Sagittal 3D T2 SPACE Thoracic Spine Sagittal 3D T2 SPACE Lumbar Spine Sagittal FSE T2 Thoracic Cord thru Conus MPR 3D axial reformatted images Thoracic/Lumbar 3D T2 SPACE FSE T2 Thoracic Cord thru Conus TR1200 ms3350 ms TE129 ms71 ms FOV300 mm (Square)370 mm (Square) Matrix320 x x 384 Time2:03 sec each2:23 sec Introduction Methods Rapid Protocol Results Discussion Conclusion

Rapid MR Cauda Equina Protocol Rapid Protocol Sagittal 3D T2 MPR 3D axial reformatted images Sagittal FSE T2 of the thoracic cord thru the conus Thoracic Sag 3D T2 Lumbar Sag 3D T2 Thoracic cord Sag FSE T2

Rapid MR Cauda Equina Protocol Combined/merged thoracic and lumbar sagittal and reformatted coronal 3D T2 Axial reformatted images of the lumbar spine from the 3D T2 sequences Rapid Protocol Sagittal 3D T2 MPR 3D axial reformatted images Sagittal FSE T2 of the thoracic cord thru the conus

94 patients presented with symptoms concerning for CES over the first 8 months of implementation. 85 were scanned using the rapid MR protocol, and 9 were imaged with standard MR sequences. Of the 94 patients scanned, 6 were determined to have CES. Results Introduction Methods Results Rapid Protocol Discussion Conclusion

15 patients had other significant pathology including demyelinating lesions, tumor, compression fracture, and severe spinal canal stenosis. 11 of these 15 patients underwent follow-up imaging using conventional MR, CT, nuclear medicine bone scan or radiographs. Results (Cont’d) Introduction Methods Results Rapid Protocol Discussion Conclusion

1 of these 11 patients had a migrated free disc fragment lateral to the neural foramen discovered on conventional MR that was not identified on rapid MR imaging. Findings from the remaining follow- up exams either supported or confirmed rapid MR imaging findings. Results (Cont’d) Introduction Methods Results Rapid Protocol Discussion Conclusion

Total # of Patients… Presenting to ED with CES- like symptoms 94 Scanned with rapid MR protocol 85 Scanned with standard MR protocol 9 Diagnosis of CES using rapid MR 6 Significant findings identified other than CES 15 Received follow-up imaging 11 Significant findings on follow-up imaging not identified on rapid MR 1

Large field of view and zoomed sagittal and reformatted axial 3D T2 sequences demonstrate a large L4/5 disc extrusion compressing the lumbar nerve roots. L4 L5 L4 Disc Extrusion Introduction Methods Results Rapid Protocol Discussion Conclusion

T7 T8 T7 T8 T7 Sagittal large field of view and zoomed 3D T2 and sagittal FSE T2 images demonstrate a focus of cord hyperintensity with slight expansion of the cord at the T7/8 level. The patient was diagnosed with multiple sclerosis after further clinical evaluation and brain imaging. Demyelinating Lesion Introduction Methods Results Rapid Protocol Discussion Conclusion

Sagittal 3D T2 images of the thoracic and lumbar spine demonstrate a vertebra plana at T9 and a large mass involving the vertebral body and posterior elements of T10. An additional lesion is seen at the S2 level. T11 T8 S1 Myeloma and Compression Fracture Introduction Methods Results Rapid Protocol Discussion Conclusion

Reformatted coronal image and multiple reformatted axial images obtained from the 3D T2 sequence better demonstrate the size and epidural extention of the mass with displacement of the cord to the right. Severe canal stenosis and mild cord compression is seen. During subsequent work-up, the patient was diagnosed with multiple myeloma. Myeloma and Compression Fracture Introduction Methods Results Rapid Protocol Discussion Conclusion

Sagittal and reformatted coronal 3D T2 images of the thoracic spine demonstrate cord hyperintensity and mild expansion at the superior aspect of the field of view. Metallic artifact is present from prior anterior cervical fusion with hardware. The abnormality was identified during the exam, and additional imaging of the cervical spine was obtained. Subacute Combined Degeneration Introduction Methods Results Rapid Protocol Discussion Conclusion

Sagittal and reformatted coronal images of the cervical spine show T2 hyperintensity from the medulla through T1 with expansion of the cord. Reformatted axial images demonstrate the hyperintensity within the dorsal columns with an inverted-V configuration which can be seen with subacute combined degneration. The patient was found to have B12 deficiency and pernicious anemia. T1 Subacute Combined Degeneration Introduction Methods Results Rapid Protocol Discussion Conclusion

Discussion Introduction Methods Discussion Rapid Protocol Results Conclusion The utilization of an abbreviated MR protocol for the evaluation of CES promotes more efficient and cost effective use of MR resources. This is accomplished partly by eliminating the redundancy of standard MR protocols. Our data suggests that eliminating this redundancy can be accomplished while maintaining the diagnostic integrity of the abbreviated MR protocol. The utilization of an abbreviated MR protocol for the evaluation of CES promotes more efficient and cost effective use of MR resources. This is accomplished partly by eliminating the redundancy of standard MR protocols. Our data suggests that eliminating this redundancy can be accomplished while maintaining the diagnostic integrity of the abbreviated MR protocol.

Discussion Standardized abbreviated imaging protocols could enable patient providers to more effectively tailor imaging studies to specific clinical scenarios. The use of an abbreviated MR protocol to evaluate CES should not be viewed as an indication to perform more spine imaging; but rather to work in conjunction with resources, such as the ACR appropriateness criteria for spine imaging, to establish more appropriate utilization of MR scanners. Standardized abbreviated imaging protocols could enable patient providers to more effectively tailor imaging studies to specific clinical scenarios. The use of an abbreviated MR protocol to evaluate CES should not be viewed as an indication to perform more spine imaging; but rather to work in conjunction with resources, such as the ACR appropriateness criteria for spine imaging, to establish more appropriate utilization of MR scanners. Introduction Methods Discussion Rapid Protocol Results Conclusion

Rapid recognition of CES is advantageous, as treatment within 24 hours is associated with the best outcomes. A variety of pathologies can elicit symptoms of CES, and some of these entities may not be detected on conventional imaging focused on the lumbar spine. Introduction Methods Conclusion Rapid Protocol Results Discussion

Conclusion Implementation of the rapid MR protocol in the emergency setting provides identification of a variety of etiologies for patients’ symptoms. Our experience suggests it may be comparable to standard imaging for evaluation of the lumbar spine, while adding detection of thoracic abnormalities and reducing imaging acquisition to less than half the time of a standard lumbar MRI evaluation. This can positively impact both MRI and emergency department work-flow. Introduction Methods Conclusion Rapid Protocol Results Discussion

References Gardner A, Gardner E, Morley T. Cauda equina syndrome: a review of the current clinical and medico-legal position. Eur Spine J 2011; 20(5): Gitelman A, Hishmeh S, Moreli B, Joseph S, Casden A, Kuflik P, Neuwirth M, Stephen M. Cauda equina syndrome: a comprehensive review. Am J Orthop 2008; 37(11): McNamee J, Flynn P, O’Leary S, Love M, Kelly B. Imaging in cauda equina syndrome – a pictorial review. Ulster Med J 2013; 82(2): Shah LM, Long D, Sanone D, Kennedy A. Application of ACR appropriateness guidelines for spine MRI in the emergency department. JACR 2014; 11(10): Sharma A. A case for changing the way we utilize MR imaging: A societal perspective. JACR 2015; 11(10):