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Published on: August 11, 2023
A Grading Scale for Pial Collaterals in Middle Cerebral Artery Total Occlusion Based on Time-of-flight MR Angiography
Huai Wu Yuan1, Ren Jie Ji1, An Li Wang2
1Department of Neurology, The First Affiliated Hospital, College of Medicine, Zhejiang University.
Purpose:
To verify whether a new grading based on time-of-flight magnetic resonance angiography source images (TOF-MRAsi) can reflect the abundance of pial collaterals, in patients with total occlusion of M1 segment of middle cerebral artery in the chronic stage.
Methods:
In this single-center retrospective study, consecutive patients with total occlusion of M1 segment of middle cerebral artery, with both magnetic resonances angiography and digital subtraction angiography image were included. Time-of-flight magnetic resonance angiography source images were evaluated in a blinded fashion for pial collaterals (PCs) that were graded on a four-point scale. Good and poor PCs were defined as TOF-MRAsis grade <2 and ≥2, respectively. Receiver operating characteristic curve analysis was done to calculate the area under curve, sensitivity, and specificity.
Results:
A total of 26 patients were included. The inter-reader agreement for time TOF-MRAsi and digital subtraction angiography images were 0.930 and 0.843, respectively. Compared with digital subtraction angiography grading, the area under curve of pial collateral grading based on TOF-MRAsi was 0.830 (0.636-1.000; P = 0.006). The sensitivity and specificity were 0.700 and 0.933, respectively. The modified Rankin Scale at follow-up was lower in patients with good PCs than in those with poor PCs (0[0, 1] vs. 1[1, 3], P = 0.055), although statistical significance was not reached.
Conclusion:
The grading scale based on TOF-MRAsi could be a new empirical approach for pial collateral evaluation. The clinical use of the proposed approach for identifying patients with total occlusion of middle cerebral artery with a high risk of poor outcome requires evaluation in further studies.
Insights
A new grading scale using time-of-flight magnetic resonance angiography source images (TOF-MRAsi) effectively reflects pial collaterals in patients with middle cerebral artery occlusion. This TOF-MRAsi grading shows promise for evaluating collateral status.
Area of Science:
- Neurology
- Radiology
- Vascular Imaging
Background:
- Pial collaterals are crucial for collateral supply in moyamoya disease and other conditions causing middle cerebral artery occlusion.
- Assessing pial collateral abundance is important for predicting outcomes.
- Current assessment methods may have limitations.
Purpose of the Study:
- To evaluate a novel grading scale based on time-of-flight magnetic resonance angiography source images (TOF-MRAsi) for assessing pial collaterals.
- To determine if this TOF-MRAsi grading correlates with collateral status in patients with chronic M1 segment middle cerebral artery occlusion.
Main Methods:
- Retrospective analysis of 26 patients with M1 segment middle cerebral artery occlusion.
- TOF-MRAsi were graded using a four-point scale by blinded readers.
- Comparison with digital subtraction angiography (DSA) grading using ROC curve analysis.
Main Results:
- High inter-reader agreement for both TOF-MRAsi (0.930) and DSA (0.843).
- TOF-MRAsi grading demonstrated good diagnostic performance with an AUC of 0.830 (P=0.006), sensitivity of 0.700, and specificity of 0.933 compared to DSA.
- Patients with good pial collaterals (TOF-MRAsi grade <2) trended towards better functional outcomes (lower mRS), though not statistically significant.
Conclusions:
- The TOF-MRAsi grading scale offers a reliable and empirical method for evaluating pial collaterals.
- This approach may serve as a valuable tool in clinical practice for patients with M1 MCA occlusion.
- Further studies are needed to validate its clinical utility in predicting poor outcomes.
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