1. Position of intrasylvian cortical branches of middle cerebral artery on MRA original image Suzuki Yasuhiro Sizuoka saiseikai general hospital Shizuoka, Japan 2009

2. Introduction
Identifying branches of middle cerebral artery (MCA) is difficult using only MR angiography (MRA).
However, MRA original image make it capable, since cerebral gyri are visible.

3. Method
Objects: eight cases examined with MRA and conventional angiography
(male 6, female 2; average age 56.6 y.o. (33-71 y.o.))
Procedure: I identified MCA M4 branches on MRA original image, referring conventional angiography, and traced branches backward into Sylvian fissure.

4. Terminology
Name of twelve cortical branches are presented by Gibo et al.
(J Neurosurg, 1981)
M1: horizontal portion
M2: insular portion
M3: opercular portion
M4: cortical portion
newly defined words:
ascending branches: 6 branches going to frontal or parietal cortex as M4 portion
(orbitofrontal – posterior parietal artery)
descending branches: 6 branches going to temporal cortex as M4 portion
(angular – temporopolar artery) M3 M2 M4 M1

5. Angiography of typical case (68 y. o
Angiography of typical case (68 y.o. male) arteries: orbitofrontal, prefrontal, precentral, central, anterior parietal, posterior parietal, angular, temporaloccipital, posterior temporal, middle temporal, anterior temporal, temporopolar

6. Branch pattern of this case (right and left branches differ)
orbitofrontal
prefrontal
precentral
central
anterior parietal
posterior parietal
angular
temporaloccipital
posterior temporal
middle temporal
anterior temporal
temporopolar
right
orbitofrontal
prefrontal
precentral
central
anterior parietal
posterior parietal
angular
temporaloccipital
posterior temporal
middle temporal
anterior temporal
temporopolar
superior
trunk
superior
trunk M1 M1
inferior
trunk
inferior
trunk
early branch

7. Temporopolar arteries originate from inferior trunk or from M1 (as early branches) in medial spaces of temporal lobes
typical case
overwright of eight cases

8. Temporopolar arteries go down along temporal ridge
Temporopolar arteries go down along temporal ridge. Anterior and middle temporal arteries are seen in medial and lateral spaces of temporal lobes.
typical case
overwright of eight cases

9. Peak of temporopolar artery is approximately in this slice
Peak of temporopolar artery is approximately in this slice. Anterior, middle, posterior temporal arteries, and temporaloccipital arteries are seen in medial and lateral space of temporal lobes.
overwright of eight cases
typical case

10. M3 portions of orbitofrontal arteries are in anterior ascending rami (AAR) of Sylvian fissure. M3 portions of anterior and middle temporal arteries are under AAR of Sylvian fissure.
typical case
overwright of eight cases

11. M3 portions of prefrontal arteries are in AAR of Sylvian fissure
M3 portions of prefrontal arteries are in AAR of Sylvian fissure. M3 portions of posterior temporal arteries are under central sulci.
overwright of eight cases
typical case

12. M3 portions of precentral arteries are in AAR or under central sulci
M3 portions of precentral arteries are in AAR or under central sulci. M3 portions of posterior temporal arteries are under central sulci.
overwright of eight cases
typical case

13. Peak of orbitofrontal artery is approximately in this slice
Peak of orbitofrontal artery is approximately in this slice. M3 portions of temporaloccipital and angular arteries are under postcentral sulci.
overwright of eight cases
typical case

14. In this slice and upper slices, most M2 arteries are ascending branches. M3 portions of central arteries are under central sulci or under postcentral sulci.
overwright of eight cases
typical case

15. M3 portions of central arteries are under central sulci or under postcentral sulci. M3 portions of anterior parietal arteries are under postcentral sulci.
overwright of eight cases
typical case

16. M3 portions of anterior parietal arteries are under postcentral sulci
M3 portions of anterior parietal arteries are under postcentral sulci. M3 portions of posterior parietal arteries are at posterior terminal of Sylvian fissure.
overwright of eight cases
typical case

17. M3 portion of MCA cortical branches
Ascending
branches
Descending branches
Under triangle part of frontal lobe
Temporopolar A.
In or under AAR of Sylvian fissure
Orbitofrontal A.
Prefrontal A.
Precentral A.
Anterior temporal A.
Middle temporal A.
Under central sulcus
Central A.
Posterior temporal A.
Under postcentral sulcus
Anterior parietal A.
Temporaloccipital A.
Angular A.
Posterior terminal of Sylvian fissure
Posterior parietal A.

18. Conclusions
Identification of branches is not possible without clarifying whether the branch is ascending or descending on M4 portion.
In upper half of insula, only ascending branches exist in M2 portion, and identification is easy.
In lower half of insula, ascending and descending branches are mixed and complicated.