Spinal Cord Magnetic Resonance Angiography - Spinal MRA
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Presentation on arterial and vascular anatomy of the spinal cord, Magnetic Resonance Angiography technique and Pitfalls and some example of pathology
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Spinal Cord Magnetic Resonance Angiography - Spinal MRA
- 1. Anatomy , Technique, Pathology
- 2. Summary Vascular anatomy of the spine MR Technique Pathology
- 3. Vascular Anatomy: Part I: Spinal Arterial Anatomy
- 4. - The basic arrangement of the spinal system consists of a metameric grid of trasversely oriented segmental vessels, connected by various longitudinal channels - Primitive embryonic vascular system of the spine http://neuroangio.org/
- 6. Psyco by Alfred Hitchcock - 1960 - AORTA Thoracic segment (the easiest one!) Segmental arteries Intercostal branches Radicular and radiculomedullary arteries!!!! http://neuroangio.org/
- 8. Radiculomedullary Anterior Spinal Artery Axial View http://neuroangio.org/
- 9. Anterior Spinal Artery 1) Origin from the vertebral arteries 1) Longitudinal vessel connecting transversely oriented segmental arteries 3) Located on the ventral surface of the cord, in the median fissure
- 10. Origin of the ASA from the Vertebral Arteries Circle of Willis Vertebral Artery Vertebral Artery ASA
- 11. Anterior Spinal Artery 1) It is bigger in the cervical and lumbar tract 2) Larger segments of the ASA are associated with larger radiculomedullary arteries at those levels (Artery of Adamkiewicz – lumbar; and Lazhortes – cervical)
- 13. Posterior Spinal Arteries 1) They are two, origin from the vertebral arteries 2) Dorsal surface of the spinal cord 1) Receiving blood from the radiculary arteries
- 16. Are you guys bored?? ?? Henry Gray – Anatomist 1827-1861 Author of “Gray’s Anatomy” Grey’s Anatomy What do you think…?!? Lovely anatomy….
- 17. Vascular Anatomy: Part II: Spinal Venous Anatomy
- 18. Venous System of the Spine INTRINSIC EXTRINSIC EXTADURAL CENTRAL PERIPHERAL PIAL VENOUS NETWORK VENTRAL AND DORSAL MEDIAN VEINS(axial oriented) (longitudinal oriented)
- 19. Lasjaunias and Berenstein 1990; Griessenauer et al. 2015 Intrinsic System Extrinsic Pial network Anterior and posterior spinal veins(follow the arteries)
- 20. Anterior and Posterior Spinal Veins (number can vary 1 to 3) Radicular Vein (follows radicular artery) Radicular veins are the connection between the extrinsic and extradural venous system!!!
- 21. Venous System of the Spine INTRINSIC EXTRINSIC EXTADURAL CENTRAL PERIPHERAL PIAL VENOUS NETWORK VENTRAL AND DORSAL MEDIAN VEINS(axial oriented) (longitudinal oriented)
- 22. Extradural System 1) Internal vertebral plexus (within the vertebral canal) 2) External vertebral plexus (surrounds the vertebral column) 3) Basi-vertebral Plexus (within the vertebral body) 4) Intervertebral veins
- 23. Axial T1 post Gadolinium 1) Basivertebral Vein 2) Anterior Internal venous plexus
- 24. Extradural System INTERVERTEBRAL VEINS VERTEBRAL, DEEP CERVICAL AND JUGULAR VEINS (Cervical level) AZYGOS/EMIAZYGOS (Thoracic and Lumbar Levels) ASCENDING LUMBAR VEINS (Lumbar and sacral levels) SUPERIORVENACAVAINFERIORVENACAVA
- 25. (Cervical level) (Thoracic and Lumbar level)
- 28. Catheter Angiography Is the Gold Standard for spinal vascular lesions DIAGNOSIS LOCALIZATION CLASSIFICATION
- 29. Catheter Angiography: Drawbacks RADIATION/INVASIVE PROCEDURE TIME CONSUMING MAJOR COMPLICATIONS PERFORMED ONLY BY EXPERTS
- 30. SPINAL CORD MR ANGIOGRAPHY : GOALS 1) Localizing normal arteries and veins (surgical and interventional applications) 2) Pathology Aortic Aneurysm surgery: identification of AKA will avoid spinal cord ischemia Avoid AKA embolization during treatment of vascular malformations
- 31. SPINAL CORD MR ANGIOGRAPHY : REQUIREMENTS COVERAGE SPATIAL RESOLUTION TEMPORAL RESOLUTION “Improving one of these items generally degrades one or both of the other requirements” Backes et al. AJNR 2008
- 32. COVERAGE AKA : may originate from any segmental artery of the thoracolumbar spine CC FOV = 50 cm Takase et al. Radiology 2002
- 33. SPATIAL RESOLUTION Spinal Vessels have sub-millimeter to millimeter calibers
- 34. TEMPORAL RESOLUTION Spatial courses of arteries and veins similar Temporal differences in arrival and transit time
- 35. Phase 1 : arteries Phase 2 : arteries + veins AJNR Am J Neuroradiol 29:619 –31 Apr 2008 AV circulation time 9-12 sec
- 36. SPINAL CORD MR ANGIOGRAPHY : TECHNIQUE - TOF and PCA techniques have good spatial resolution but are not able to depict the normal spinal arteries - Vessel-to-background contrast depends on high flow - Flow in small spinal vessels is too low to provide enough signal intensity changes - Poor suppression of background tissue signalPattany PM, Saraf-Lavi E, Bowen BC. MR angiography of the spine and spinal cord. Top Magn Reson Imaging 2003;14:444–60
- 37. CONTRAST ENHANCED 3D MR ANGIOGRAPHY BOLUS OF CONTRAST: 0.2-0.3 mmol Gd-DTPA/kg at 3 mL/s SHORTEST TE (2-8 ms): Best signal of enhanced blood / minimizing T2* degrading effect SHORTEST TR (< 10 ms): Best suppression of the background (spine, CSF, cord tissue) 3D Fast-Gradient recalled echo with centric K-space filling ACQUISITION TIME 40 sec FOR EVERY DATA SET: But the AV transit time is about 10 sec timing of arrival of bolus + synchronizing centric K space sampling NB: scan delay acquisition time is set with 2 ml test bolus by MR fluoroscopy or with auto triggering
- 38. Dynamic acquisition every second of single 80 mm thick sagittal section through aorta Timing Bolus
- 39. AUTOMATED TRIGGERING - IV contrast injection followed by continuous image acquisition - When the desired signal intensity is reached the proper contrast enhancement is started - Automated triggering is better for the centric k-space filling - Better for Pediatric MRA: Tot volume injected in children is 1-2 mL
- 40. Temporal Signal intensity changes: 10 seconds of difference between signal from arteries and veins
- 41. Backes et al. AJNR 2008
- 42. Phase 1 : arteries Phase 2 : arteries + veins MPR REFORMATS SEGMENTAL ARTERIES & VEINS AKA AKA GARV GARV AJNR Am J Neuroradiol 29:619 –31 Apr 2008
- 43. CLEAR SO FAR??!!
- 44. PATHOLOGY SPINAL ARTERIOVENOUS MALFORMATION - Abnormal arteriovenous communication in spinal cord or dura mater - May have extra medullary and extradural components - Complex classification
- 45. Abnormal radicular feeding artery Nidus of the malformation Dilated draining vein https://my.statdx.com/
- 46. Cord edema Flow voids Flow voids Tortuous draining vein https://my.statdx.com/
- 47. Mull et al. AJNR 2006 Dilated draining vein T2 Dilated draining vein MRA Feeding artery
Editor's Notes
- - From segmental arteries there are feeding vessels for the bone marrow(D in the figure) - Than segmental arteries divides in intercostal branches and dorsal branches, which goes to the posterior element of the column (H in figure) and to the pia/dura and medulla (Ka and P)
- L’aorta non si vede in questa figura, G si chiama PRETRANSVERSE ANASTOMOTIC NETWORK
- This shows the origin from the vertebral arteries.
- …not to be confused with….
- Another scream from greys anatomy….. I don’t know why I had thisobsession with greys anatomy preparing this presentation…. But anyway…
- Intrinsic system : Longitudinal (1) and axial (2;3) oriented intrinsic system. In red. You will never see this intrinsic system on imaging. Extrinisc pial network: on the surface of the spine (green): remember the pia is the closest membrane surrounding the spinal cord!! Extrinsix longitudinal veins (anterior and posterior) : in yellow they follow the anterior and posterior spinal arteries.
- In this pic there are 3 post and 1 ant but the number can vary according to the spinal segment and the person.
- Internal and external vertebral plexi are anterior and posterior
- Where the blood from intervertebral veins goes? CERVICAL LEVEL VEIN OF THE NECK, THORACIC LEVEL: VEIN OF THE THORAX , LUMBAR VEINS
- LEFT: Cervical level, vein drainage vertebral plexus of the vertebral artery, vertebral veins and deep cervical vein. RIGHT:
- Note the cervical venous drainage and the thoracic drainage through intervertebral veins.
- Our expert DEREK
- Balancment among : coverage , spatial resolution and temporal resolution
- Let’s explain every single of these goal: 1) coverage , because the aka (very important!) can may originate from any semgnetal artery of the thoracolumbar spine , so it has a variable location.
- Let’s explain every single of these goals
- Let’s explain every single of these goals
- AV circulation time depends upon age, anesthesia, segment of the spine analyzed.
- Shortest TE (eco time) means best signal of enhanced blood because of the T1 shortening of the blood with high concentration of Gadolinium Shortest TR (repetition time): the background have relatively longer T1 relaxation time in comparison with enhanced blood. Centric K space filling means that the lowest spatial frequency point are sampled first, this central points contribute most to overall image contrast which is timed to arrival of arterial bolus.
- This is the second technique to coordinate the acquisition with the arterial time. It is better in case of central fillin of k-space since the k space is filled in the center at peak of enhancement.
- NB: second phase will be also useful in order to identify vertebral levels which is birght in
- Parameter proposed by Backes for a 1.5 T we have already seen most of them. Just remember the frequency encoding is CC because follow the major axis of the body part to be analyzed (in this case being the spine). Remember a phase of precontrast acquisition used for subtraction. Acquisition is sagittal
- GARV GREAT ANTERIOR RADICULO-MEDULLARY VEIN
- (A) MR image from a patient with acute onset of paraplegia shows extensive serpiginous flow voids (white curved arrow) along the dorsal surface of the spinal cord and increased signal (white solid arrow) within the cord, reflecting edema. (B) MRA MIP image shows the tortuous draining veins (white open arrow) of the AVM, corresponding to the flow voids.
- Feeding artery from T8 level.
- I hope I was more clear than that!