1. Concurrent Demonstration of Cerebral Infarction and the Involved Pyramidal Tract by 3D-FLAIR Imaging Using a Variable Refocusing Flip Angle
Kazuhiro Tsuchiya, Motoyuki Yamashita, Naoki Shimatani
Misako Yorimitsu, Motonori Kokan, Takeo Suzuki, Shuichi Ichisaka
Department of Radiology, Tokyo Teishin Hospital
Tokyo, Japan

2. ☑ The author has no conflict of interest to disclose with respect to this presentation.

3. Background and Purpose
We have found that FLAIR imaging using a VISTA (Volume ISotropic TSE Acquisition) sequence can highlight some major nerve tracts by changing a refocusing flip angle (RFA) from that (60°) recommended by the vendor for conventional FLAIR contrast. We assessed the feasibility of the FLAIR VISTA sequence in demonstrating the pyramidal tract (PT) and an infarct that developed in its vicinity on one image.

4. VISTA （Volume ISotropic TSE Acquisition）
Available for imaging of T1WI, T2WI, and FLAIR
3D non volume-selective　→　 echo space↓, blurring↓
Refocusing flip angle　→ 　pseudo steady state, long ETL
Signal Gx Gy Gz RF
90° RF pulse
90+α/2 α
Refocusing pulse
Echo space ↓
3D non volume selective α α

5. 3D FLAIR VISTA images obtained with an RFA of 110° show the pyramidal tract as a hyperintense structure.

6. Contrast of the pyramidal tract changes according to the RFA.
Normal volunteer (34F)

7. Comparison of diffusion tensor color map and tractography shows good correspondence.

8. SNR/CNR assessments at various RFAs in 5 volunteers show 110 ° as a favorable value.
Recommended value by PHILIPS

9. Patients
Fifteen patients (9 men, 6 women; aged 45 to 87 years, average age 65.8 years ) of acute/subacute infarction who underwent MR imaging including the FLAIR VISTA sequence (RFA=110°) between June, 2013 and March, 2014.
Equipment : PHILIPS Achieva 1.5T (Release 2.6)

10. Methods 1.5-T imager (PHILIPS Achieva Release 2.6)
Imaging parameters: TR/TE/TI, 6000/312/2000 ms; FOV, 250 mm; matrix, 208 x 208; slice thickness. 0.6 mm; SENSE factor, 2.8 (phase) x 2 (slice); flip angle, 90°; turbo factor, 140; and imaging time; 6 min 18 sec; scan plane, sagittal followed by reconstruction of coronal images
Images were visually assessed by consensus reading of 2 experienced radiologists regarding the visualization of the pyramidal tract and the infarct using a three-point grading scale (3 = good, 2 = fair, 1 = poor).
Equipment : PHILIPS Achieva 1.5T (Release 2.6)

11. Patient clinical data and summary of MR findings
Symptoms
MR findings PT
visualization
62M
transient weakness of LUE
R temporal infarction 3
45M
dysarthria, weakness of RUE
L posterior limb of the internal capsule infarction
64F
R hemiplegia, total aphasia
L MCA area infarction
87F
L basal ganglia/corona radiata infarction
65F
weakness of RUE, limb ataxia
R thalamus infarction
DOC
L frontotemporal infarction
weakness of LUE, limb ataxia
R thalamus/posterior limb of the internal capsule infarction
79M
DOC, L hemiparesis
51M
numbness of LUE, L hemiparesis
R corona radiata/putamen, and frontal subcortical infarction
61M
R hemiplegia
L frontoparietal infarction
54F
transient dysarthria, slight L facial palsy
R posterior limb of the internal capsule infarction
56M
dysarthria, headache
R corona radiata infarction
70M
dysarthria, slight R facial palsy
73M
R hemiplegia, L concomitant deviation
L PCA area infarction
68M
weakness of RUE
wamble ふらつき
*R : right, L : left, LUE : left upper extremity , RUE : right upper extremity, DOC : disturbance of consciousness MCA: middle cerebral artery, PCA: posterior cerebral artery

12. Summary of results
In all of the 15 cases, the PT was depicted on both sides.
FLAIR VISTA images also showed the PT and the adjacent
infarct that caused motor paresis of a variable degree.
The average grading score was 3.

13. Case 1
(62M)
transient weakness of left upper extremity after right cervical pain

14. Case 1
(62M)
transient weakness of left upper extremity after right cervical pain

15. Case 1
(62M)
transient weakness of left upper extremity after right cervical pain

16. Case 2
(45M)
dysarthria and weakness of right upper extremity

17. Case 2
(45M)
dysarthria and weakness of right upper extremity

18. Case 3
(65F)
weakness of right upper extremity and limb ataxia

19. Case 3
(65F)
weakness of right upper extremity and limb ataxia

20. Case 3
(65F)
weakness of right upper extremity and limb ataxia

21. Discussion The PT was depicted on both sides in all cases probably
reflecting histological characteristics of anisotropic fibers.
Limitation of this method
Not available in acute infarction that is not hyperintense on FLAIR images
Advantages of this method　
This method may be available for lesions other than infarct (e.g., tumors and demyelinating diseases).
It may present different contrast of infarct from conventional 3D FLAIR (RFA=60°).
→ possibly depict infarct in an earlier stage than
conventional method?
The PT was depicted on both sides in all cases.
＜Limitation＞
Not available in acute infarction that is not hyperintense on FLAIR images
＜Advantages＞　
Possibly available for other lesions
(ex. tumor and demyelinating disease)
May present different contrast of infarct from conventional 3D FLAIR (RFA=60 deg)
→ depict infarct in an earlier stage than
conventional method?

22. Conclusion
The 3D FLAIR VISTA technique using a RFA of 110° readily visualizes the relationship between the PT and cerebral infarct involving it.
The FLAIR VISTA technique allows prompt visualization of the relationship between the PT and an adjacent infarct without complicated postprocessing.
Probably reflecting histological characteristics of anisotropic fibers, the FLAIR VISTA technique can readily visualize the relationship between the PT and cerebral infarct involving it.