The yield of initial conventional MRI in 115 cases of angiographically confirmed spinal vascular malformations

Abstract

MRI is the primary screening tool for patients with myelopathy. The decision to obtain additional imaging, notably spinal angiography, is generally based on initial MRI findings. This study retrospectively analyzed the yield of initial MRI in a cohort of patients with angiographically confirmed vascular malformations. MRI obtained at symptom onset was available in 115 patients with either high-flow (29 cases) or low-flow (86 cases) vascular malformations. MRI was classified as "positive" when the report mentioned a vascular malformation or "negative" when considered normal or when another diagnosis was suggested. Initial MRI was positive in 61 patients (53.0%), correctly identifying 28 high-flow (96.6%) but only 33 low-flow (38.4%) lesions. Flow voids were noted in 96.6% of the high-flow lesions and 38.4% of the low-flow ones. T2-signal anomalies (77.4%) and parenchymal enhancement (54.5%) were also common in low-flow anomalies. Patients with negative MRI had an average delay of 111 days before angiography and 239 days before therapy; these intervals were 27 and 76 days for those with positive MRIs. In summary, MRI shows a high yield for high-flow vascular malformations, i.e., characterized by prominent flow voids on T2-weighted images, but misdiagnosed over 60% of low-flow lesions. The percentage of correctly identified anomalies matched the percentage of observed flow voids in both groups, indicating over-reliance on this sign for the diagnosis of slow-flow lesions. MRI findings in slow-flow vascular malformation overlap with other conditions, notably transverse myelitis, which was initially misattributed to 40% of the slow-flow lesions in our cohort.

Comparative Analysis of Volumetric High-Resolution Heavily T2-Weighted MRI and Time-Resolved Contrast-Enhanced MRA in the Evaluation of Spinal Vascular Malformations

“…3 Flow voids, however, are observed in only about 70% of cases; moreover, the detection rate could be very low (Ͻ40%) in low-flow shunt lesions. 3,14 Advanced MR images can improve the sensitivity and diagnostic accuracy for the detection of SVM. Amarourche et al 10 reported the utility of the TRCE MR imaging technique (TRICKS) in the evaluation of different types of SVMs.…”

“…10,11,17 In our study, we found that VHHT2WI and TRCE MR imaging had high sensitivity and accuracy in the diagnosis of SVM, concurrent with other reported studies in the literature. [10][11][12][13][14][15] Although the diagnosis of SDAVF could be confidently made using either sequence, a false-positive diagnosis was a concern for both. In our series, 2 cases of PMAVF and 1 case each of PMAVF and SCAVM were erroneously diagnosed as SDAVFs.…”

Intracranial dural arteriovenous fistula mistaken as cervical transverse myelitis

“…In a large retrospective study, MRI had a sensitivity of 38% for angiographically confirmed low-flow spinal vascular lesions and 40% of cases were initially misdiagnosed as myelitis 2. Gadolinium enhancement is often interpreted to indicate acute inflammation1 but it is not specific and this may also occur in dural arteriovenous fistula due to chronic venous congestion and breakdown of the blood–spinal cord barrier.…”

ACR Appropriateness Criteria® Myelopathy: 2021 Update

“…There may be patchy intramedullary enhancement due to breakdown of the blood-cord barrier. In some cases, abnormal vasculature may be identified that may be useful to guide spinal arteriography and intervention [5,[89][90][91].…”

“…A variety of cysts and benign neoplasms can also compress the cord; they tend to arise within the intradural compartment. The most common of these are nerve sheath tumors, meningiomas, and arachnoid adhesions/cysts [4][5][6][7][8][9][10].…”