spinal cord magnetic resonance angiography - spinal mra
TRANSCRIPT
Spinal Cord MR Angiography
Felice D’Arco
Anatomy , Technique, Pathology
Summary
Vascular anatomy of the spine
MR Technique
Pathology
Vascular Anatomy:Part I: Spinal Arterial
Anatomy
- 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/
Overtime…
http://neuroangio.org/
Psyco by Alfred Hitchcock - 1960 -
AORTA
Thoracic segment (the easiest one!)
Segmental arteries
Intercostal branches
Radicular and radiculomedullary
arteries!!!!
http://neuroangio.org/
Radiculomedullary
Anterior Spinal Artery
http://neuroangio.org/
Radiculomedullary
Anterior Spinal Artery
Axial View
http://neuroangio.org/
Anterior Spinal Artery1) Origin from the vertebral
arteries
2) Longitudinal vessel connecting
transversely oriented segmental arteries
3) Located on the ventral surface of the cord, in the
median fissure
Origin of the ASA from the Vertebral Arteries
Circle of Willis
Vertebral Artery
Vertebral Artery
ASA
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)
https://www.imaios.com/
Posterior Spinal Arteries
1) They are two, origin from the vertebral arteries
2) Dorsal surface of the spinal cord
3) Receiving blood from the radiculary arteries
Posterior Spinal Arteries
Anterior Posterior
To summarize…
Are you guys
bored????
Henry Gray – Anatomist1827-1861
Author of “Gray’s Anatomy” Grey’s Anatomy
What do you
think…?!?
Lovely anatomy….
Vascular Anatomy:Part II: Spinal Venous
Anatomy
Venous System of the Spine
INTRINSIC EXTRINSIC EXTADURAL
CENTRAL PERIPHERAL
PIAL VENOUS
NETWORK
VENTRAL AND
DORSAL MEDIAN VEINS(axial
oriented) (longitudinal oriented)
Lasjaunias and Berenstein 1990; Griessenauer et al. 2015
Intrinsic System
Extrinsic Pial
network
Anterior and
posterior spinal veins(follow the arteries)
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!!!
Venous System of the Spine
INTRINSIC EXTRINSIC EXTADURAL
CENTRAL PERIPHERAL
PIAL VENOUS
NETWORK
VENTRAL AND
DORSAL MEDIAN VEINS(axial
oriented) (longitudinal oriented)
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
Axial T1 post Gadolinium1) Basivertebral Vein
2) Anterior Internal venous plexus
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)
SUPERIOR VENA CAVAINFERIOR VENA CAVA
(Cervical level) (Thoracic and Lumbar level)
Dilated Extradural System
SPINAL CORD MR ANGIOGRAPHY
Catheter Angiography
Is the Gold Standard for spinal vascular
lesionsDIAGNOSIS
LOCALIZATION
CLASSIFICATION
Catheter Angiography: Drawbacks
RADIATION/INVASIVE PROCEDURE
TIME CONSUMING
MAJOR COMPLICATIONS
PERFORMED ONLY BY EXPERTS
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
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
COVERAGEAKA : may originate from any
segmental artery of the thoracolumbar spine
CC FOV = 50 cm
Takase et al. Radiology 2002
SPATIAL RESOLUTIONSpinal Vessels have sub-millimeter
to millimeter calibers
TEMPORAL RESOLUTION
Spatial courses of arteries and veins similar
Temporal differences in arrival and transit time
Phase 1 : arteries
Phase 2 : arteries +
veins
AJNR Am J Neuroradiol 29:619 –31 Apr 2008
AV circulation time 9-12 sec
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 signal
Pattany PM, Saraf-Lavi E, Bowen BC. MR angiography of the spine and spinalcord. Top Magn Reson Imaging 2003;14:444–60
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 samplingNB: scan delay acquisition time is set with 2 ml test bolus by
MR fluoroscopy or with auto triggering
Dynamic acquisition every second of single 80 mm thick sagittal section through aorta
Timing Bolus
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
Temporal Signal
intensity changes:
10 seconds of
difference between
signal from arteries
and veins
Backes et al. AJNR 2008
Phase 1 : arteries
Phase 2 : arteries +
veins
Aorta
Aorta
MPR REFORMATS SEGMENTAL ARTERIES & VEINS
AKA AKA
GARV GARV
AJNR Am J Neuroradiol 29:619 –31 Apr 2008
CLEAR SO FAR??!!
PATHOLOGYSPINAL ARTERIOVENOUS
MALFORMATION
- Abnormal arteriovenous communication in spinal
cord or dura mater
- May have extra medullary and extradural components
- Complex classification
Abnormal radicular
feeding artery
Nidus of the malformatio
n
Dilated draining vein
https://my.statdx.com/
Cord edema
Flow voids
Flow voids
Tortuous draining vein
https://my.statdx.com/
Mull et al. AJNR 2006
Dilated draining vein T2
Dilated draining vein MRA
Feeding artery