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