Usefulness of Time–Resolved MR Angiography in Spinal Dural Arteriovenous Fistula (SDAVF) — a Systematic Review and Meta–Analysis

Introduction: Spinal dural arteriovenous fistulas (SDAVFs) constitute the most common type of spinal vascular malformations. The diagnosis of SDAVF requires spinal digital subtraction angiography (DSA), which is a time–consuming study that requires catheterizing many vessels, exposes patient to a high radiation and contrast doses. This study aims to evaluate the usefulness of TR–MRA in SDAVF diagnosis.

Methods: We performed a systematic review of the PubMed and EMBASE databases followed by a meta–analysis. TR–MRA was an index test and spinal DSA was a reference.

Results: Of the initial 324 records, we included 4 studies describing in total 71 patients with SDAVF. In total 71 TR–MRAs and 67 spinal DSAs were performed. In 4 cases with negative TR–MRAs, spinal DSAs were called off. In 42 cases TR–MRA was true positive and in 21 cases it was true negative. We found 7 false positive cases and 1 false negative. TR–MRA allowed for shunt level identification in a total of 39 cases. Of these, the predicted level was correct in 23 cases (59%), to within 1 level in 38 cases (97.4%) and to within 2 levels in 39 cases (100%). The diagnostic odds ratio was 72.73 (95% CI [10.30; 513.35]), z=4.30, p-value < 0.0001. The pooled sensitivity was 0.98 (95% CI [0.64; 1.00]) and the pooled specificity was 0.79 (95% CI [0.10; 0.99]). The AUC of the SROC curve was 0.9.

Conclusion : TR–MRA may serve as a preliminary study to detect SDAVFs and localize the shunt level with sensitivity and specificity as high as 98% and 79%, respectively. Unless the TR–MRA result is unequivocal, it should be followed by a limited spinal DSA. Future studies are needed to further evaluate TR–MRA and advance its technological development.