Morphological Study on Lenticulostriate Arteries in Patients With Middle Cerebral Artery Stenosis at 7 T MRI.

BACKGROUND

Middle cerebral artery (MCA) stenosis affects lenticulostriate arteries (LSAs) that supply the basal ganglia. Increased spatial resolution and signal-to-noise ratio of 7 T could facilitate morphological imaging of very-small-diameter LSAs.

PURPOSE

To evaluate differences in morphological characteristics of LSA among different MCA stenoses.

STUDY TYPE

Prospective.

SUBJECTS

We enrolled 161 patients (age: 26-83 years, 115 males) with MCA-M1-segment stenosis, and assigned them to the symptomatic (ischemic stroke on imaging, or transient ischemic attack diagnosed clinically within 90 days) and asymptomatic (mild-to-moderate stenosis, ≤70% diameter reduction and severe stenosis, >70% and ≤99% diameter reductions) groups and further subdivided them into the proximal and distal stenosis subgroups.

FIELD STRENGTH/SEQUENCE: 7 T, three-dimensional time-of-flight magnetic resonance angiography (3D TOF-MRA).

ASSESSMENT

The number of LSA stems, branches, length, and tortuosity (LSA length/linear distance between LSA start- and endpoints) were evaluated independently in both hemispheres by 3 radiologists with 2-, 10-, and 12-years' experience, and inter-group and inter-subgroup comparisons were undertaken.

STATISTICAL TESTS

Independent t tests, paired t tests, chi-square test, and multiple linear regression analysis (P < 0.05 indicated statistical significance).

RESULTS

Compared with the asymptomatic group (N = 76), the symptomatic group (N = 85) had significantly fewer LSA branches (7.58 ± 2.31 vs. 9.29 ± 2.37) and shorter length (4.32 ± 0.84 vs. 4.59 ± 0.72 cm). There were no significant intergroup differences in LSA morphological characteristics between the mild-to-moderate and severe-stenosis subgroups (LSA stems: P = 0.457, LSA branches: P = 0.433, LSA length: P = 0.150, and LSA tortuosity: P = 0.613). The proximal stenosis subgroup had significantly fewer (8.08 ± 1.80 vs. 10.64 ± 2.21) and shorter LSA branches (4.43 ± 0.69 vs. 4.76 ± 0.71 cm) than in the distal stenosis subgroup. Multiple linear regression, after false discovery rate correction, showed that symptoms and the MCA-M1-segment-stenosis site (proximal/distal) were significantly associated with LSA and length.

DATA CONCLUSION

Having symptoms and a proximal MCA-M1 segment stenosis were associated with fewer LSA branches, whereas stenosis severity did not significantly affect LSA morphological characteristics.

PLAIN LANGUAGE SUMMARY

Lenticulostriate arteries mainly originate from the middle cerebral artery, which 7 T magnetic resonance imaging (MRI) can help visualize effectively. We mainly focused on evaluating lenticulostriate artery stems, branches, length, and tortuosity (length/linear distance between start- and endpoints) among 3 types of middle cerebral artery stenoses (symptomatic and asymptomatic, mild-to-moderate and severe stenosis, and proximal and distal stenosis). Symptomatic patients with proximal MCA stenosis had fewer lenticulostriate artery branches (7.58 ± 2.31 vs. 9.29 ± 2.37 and 8.08 ± 1.80 vs. 10.64 ± 2.21). This research based on the morphological perspective clearly depicted the lenticulostriate artery using 7 T MRI to provide more intuitive results.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 3.