Isolated aortic origin of the intersegmental spinal branch

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

BACKGROUND AND PURPOSE

Volumetric high-resolution heavily T2-weighted imaging or time-resolved contrast-enhanced MRA is used in the detection and characterization of spinal vascular malformations, though inherent trade-offs can affect their overall sensitivity and accuracy. We compared the efficacy of volumetric high-resolution heavily T2-weighted and time-resolved contrast-enhanced images in spinal vascular malformation diagnosis and feeder characterization and assessed whether a combined evaluation improved the overall accuracy of diagnosis.

MATERIALS AND METHODS

Twenty-eight patients with spinal vascular malformations (spinal dural arteriovenous fistula, spinal cord arteriovenous malformation, and perimedullary arteriovenous fistula) were prospectively enrolled. MR images were separately analyzed by 2 neuroradiologists blinded to the final diagnosis.

RESULTS

Both sequences demonstrated 100% sensitivity and 93.5% accuracy for the detection of spinal vascular malformations. Volumetric high-resolution heavily T2-weighted imaging was superior to time-resolved contrast-enhanced MR imaging for identification of spinal cord arteriovenous malformations (100% versus 90% sensitivity and 96.7% versus 93.5% accuracy), however, for the diagnosis of perimedullary arteriovenous fistula, time resolved contrast enhanced MRI was found to perform better than the volumetric T2 sequence (80% versus 60% sensitivity and 96.7% versus 93.5% accuracy). Both sequences showed equal sensitivity (100%) and accuracy (87%) for spinal dural arteriovenous fistulas. Combined evaluation improved the overall accuracy across all types of spinal vascular malformation. Volumetric high-resolution heavily T2-weighted imaging was superior or equal to time-resolved contrast-enhanced MR imaging for feeder identification of spinal dural arteriovenous fistulas for both observers (90.9% and 72.7% versus 72.7%), which improved to 90.9% when the sequences were combined. Time-resolved contrast-enhanced MR imaging performed better for major and total feeder identification of spinal cord arteriovenous malformation (80% versus 60%) and perimedullary arteriovenous fistula (80% versus 60%-80%).

CONCLUSIONS

Combined volumetric high-resolution heavily T2-weighted imaging and time-resolved contrast-enhanced MR imaging can improve the sensitivity and accuracy of spinal vascular malformation diagnosis, classification, and feeder characterization.

Volumetric T2-weighted MRI improves the diagnostic accuracy of spinal vascular malformations: comparative analysis with a conventional MR study

Background

To date, very little study of the importance of a volumetric T2-weighted MR sequence in the evaluation of spinal vascular malformations (SVMs) has been carried out.

Objective

To determine the utility and accuracy of a volumetric T2 MR sequence compared with conventional T2 in the diagnosis of SVMs.

Methods

Retrospective analysis of all patients who underwent spinal DSA for suspected SVMs was conducted. Conventional T2 and volumetric T2 MR images were analysed for the presence of flow voids and parenchymal changes, and SVMs were characterized. The sensitivity, specificity, and overall diagnostic accuracy of these MRI diagnoses were calculated.

Results

Of 89 subjects included in the final analysis, 70 patients had angiographically proved SVMs (38 patients with spinal cord arteriovenous malformations [SCAVM—intramedullary or perimedullary] and 32 cases of spinal dural arteriovenous fistula (SDAVF)) and the remaining 19 subjects were normal. The sensitivity and specificity for identification of SVMs were 98.1% and 90% for volumetric T2 sequences, compared with 82.8% and 89.4% for conventional T2 MRI, respectively. For characterization of spinal vascular lesions, volumetric MRI showed high sensitivity, specificity, and accuracy for SDAVF (100%, 90%, 97%, respectively) compared with conventional T2 MRI (71.8%, 89%, 79%, respectively). The positive likelihood ratio was high and negative likelihood ratio was zero for volumetric MRI evaluation of SDAVF, while these ratios were comparable between the two sequences for SCAVM.

Conclusion

Volumetric T2 MRI is highly sensitive for the detection of SVMs, especially for SDAVF. Volumetric T2 MRI could be introduced into routine clinical practice in the screening of suspected SVMs.

Republished: Bilateral and symmetric isolated dorsospinal arteries with prominent anterior radiculomedullary contribution

We present the case of a 15-year-old girl with a left T7 spinal epidural arteriovenous fistula (SEAVF), in whom bilateral and symmetric isolated T9 dorsospinal arteries (DAs) were incidentally documented, each providing a significant contribution to the anterior spinal artery. Recognizing the existence of isolated DAs of direct aortic origin is critical, both for the diagnostic evaluation and for the management of spinal vascular diseases. Notably, isolated DAs tend to branch off significant radiculomedullary arteries, which vascularize the normal spinal cord but have also been shown to supply spinal vascular malformations.

Bilateral and symmetric isolated dorsospinal arteries with prominent anterior radiculomedullary contribution

We present the case of a 15-year-old girl with a left T7 spinal epidural arteriovenous fistula (SEAVF), in whom bilateral and symmetric isolated T9 dorsospinal arteries (DAs) were incidentally documented, each providing a significant contribution to the anterior spinal artery. Recognizing the existence of isolated DAs of direct aortic origin is critical, both for the diagnostic evaluation and for the management of spinal vascular diseases. Notably, isolated DAs tend to branch off significant radiculomedullary arteries, which vascularize the normal spinal cord but have also been shown to supply spinal vascular malformations.

Duplicated origin of a radiculomedullary artery supplying a perimedullary arteriovenous fistula: angiographic observation and developmental considerations

The angiographic observation of a radiculomedullary artery variation found in a patient with a spinal cord vascular malformation is presented. A posterior radiculomedullary artery arising from the left L2 intersegmental artery had a duplicated origin. Two radicular trunks were seen aiming towards the neural foramen: a dominant anterior one providing a retrocorporeal artery and the anterior limb of the radicular artery, and a smaller posterior one branching off a prelaminar artery and the posterior limb of the radicular artery. The two limbs then joined to continue as a single posterior radiculomedullary artery, which participated in the vascularization of the vascular malformation. The clinical and developmental aspects of this exceptional variant are discussed.