Synopsis

Digital subtraction angiography (DSA) is the golden standard of radiological technique for diagnosis and treatment evaluation of cerebral arteriovenous malformations (CAVMs). However, DSA is invasive and ionizing radiative. Silent MRA, which combines arterial spin labeling (ASL) and an ultrashort time echo (UTE), is used for CAVM structure visualization. The silent MRA is superior to TOF-MRA and enables the same Spetzler-Martin classification of cerebral AVM as that at DSA.

Purpose

To prospectively test the hypothesis that silent MRA is superior to TOF-MRA and enables the same Spetzler-Martin classification of cerebral AVM as that at DSA.

Methods

Institutional ethics committee approval and written informed consent were obtained. 23 consecutive patients with cerebral AVM (9 men, 14 women; mean age, 33.7 years ± 18.3; range, 5–64 years) were scanned in MRI with TOF, Silent MRA protocols and also examined with DSA.The images of TOF and Silent MRA were independently reviewed by one neuroradiologist and one neurosurgeon according to Spetzler-Martin classification comparing to DSA. Characterization of AVM, image quality, and level of confidence were evaluated by computing the Cohen k coefficient.

Result

Spetzler-Martin classification of cerebral AVM from silent MRA and DSA was matched in 23 of 23 patients for reader 1, and 22 of 23 patients for reader 2, which yielded 93.8 % interobserver agreement (K=0.938). While Spetzler-Martin classification from TOF MRA and DSA matched in 20 of 23 patients for reader 1, and 21 of 23 patients for reader 2, which yielded 81.8 % interobserver agreement (K=0.818).For AVM characterization by using silent MRA, interobserver agreement was very good to excellent, and agreement with DSA showed k of 0.86 for arterial feeders, 1.00 for AVM-related aneurysms, and k of 1.00 for venous drainage for reader 1; k of 0.93 for arterial feeders, k of 0.91 for AVM-related aneurysms, and k of 1.00 for venous drainage for reader 2. For TOF MRA, interobserver agreement was very moderate to good, and agreement with DSA showed k of 0.68 for arterial feeders, k of 0.70 for AVM-related aneurysms, and k of 0.92 for venous drainage for reader 1, k of 0.72 for arterial feeders, k of 0.47 for AVM-related aneurysms, and k of 0.92 for venous drainage for reader 2.Image quality of silent MRA was judged to be adequate to high for diagnosis in all patients for both readers, with an average level of image quality score of 2.9±0.3 (range, 2–3) for both readers, which yielded moderate interobserver agreement (k 0.777). Image quality of TOF MRA was judged to be low to high for diagnosis in all patients for both readers, with an average level of image quality score of 2.3±0.6 (range, 1–3) for reader 1 and 2.0±0.4 (range, 1–3) for reader 2, which yielded poor interobserver agreement (k 0.167).Levels of confidence of Spetzler-Martin classification as determined with silent MRA was high for both readers, with an average level of confidence of 2.9±0.3 (range 2–3) for both readers, which yielded excellent interobserver agreement (k 1.00). Levels of confidence with TOF MRA was moderate for both readers, with an average level of confidence of 2.4 ±0.6 (range 1–3) for both readers 6±0.7 (range 1–3) for both readers, which yielded fair interobserver agreement (k 0.534).

Conclusion

The results suggest that Silent MRA is a promising MR angiography technique for clinical evaluation of CAVM comparing to TOF MRA, which showed very good to excellent agreement with DSA. Interreader agreement was also better in silent MRA.

Acknowledgements

No acknowledgement found.