Evaluation of dural arteriovenous fistulas with 4D contrast-enhanced MR angiography at 3T

Abstract

Background and purpose: Four-dimensional contrast-enhanced MR angiography (4D-CE-MRA) at 3T may replace digital subtraction angiography (DSA) for certain diagnostic purposes in patients with intracranial dural arteriovenous fistula (DAVF). The aim of this study was to test the hypothesis that 4D-CE-MRA at 3T enables the same characterization of intracranial DAVFs as DSA.

Materials and methods: The study population consisted of 18 consecutive patients with intracranial DAVFs (11 women, 7 men; age range, 35-82 years; mean age, 64.8 years). They underwent 4D-CE-MRA at 3T and DSA. The 4D-CE-MRA series combined randomly segmented central k-space ordering, keyhole imaging, sensitivity encoding, and half-Fourier imaging. We obtained 30 dynamic scans every 1.9 seconds with a spatial resolution of 1 x 1 x 1.5 mm. Two independent readers reviewed the 4D-CE-MRA images for main arterial feeders, fistula site, and venous drainage. Interobserver and intermodality agreement was assessed by kappa statistics.

Results: At DSA, 8 fistulas were located at the transverse sigmoid sinus; 8, at the cavernous sinus; and 2, at the sinus adjacent to the foramen magnum. Interobserver agreement was fair for the main arterial feeders (kappa = 0.59), excellent for the fistula site (kappa = 0.91), and good for venous drainage (kappa = 0.86). Intermodality agreement was moderate for the main arterial feeders (kappa = 0.68) and excellent for the fistula site (kappa = 1.0) and venous drainage (kappa = 1.0).

Conclusions: The agreement between 4D-CE-MRA and DSA findings was good to excellent with respect to the fistula site and venous drainage.

Fig 1.

A, Anteroposterior (top row), lateral (second row), and axial (bottom row) projections of maximum-intensity 4D-CE-MRA images (2.9/1.4, 20° flip angle) reconstructed in a 65-year-old man with DAVF at the left transverse sinus. There is an early depiction of the left transverse and the right transverse-to-sigmoid sinuses at the early arterial (left) to the arterial phase (middle). The fistula site (arrow) appears to be the left transverse sinus, and the DAVF is mainly supplied by branches from the occipital artery (arrowheads). Venous drainage is from the left transverse to the right transverse to the sigmoid sinus. The left sigmoid sinus is not visualized at the venous phase (small arrow). In this DAVF, both readers judged that the occipital artery was the main arterial feeder, the left transverse sinus was the fistula site, and venous drainage was type 1. B, Anteroposterior (upper) and lateral (lower) projections of digital subtraction angiography (DSA) (left) and 4D CE-MRA (right) during the arterial phase in the patient in A. DSA shows an arteriovenous shunt (arrow) at the left transverse sinus, which is supplied by branches from the occipital artery (arrowheads). 4D-CE-MRA also depicts the main arterial feeders (arrowheads), the fistula site (arrow), and the venous drainage route.

Fig 2.

A, Anteroposterior (top row), lateral (second row), and axial (bottom row) projections of maximum-intensity 4D-CE-MRA images (2.9/1.4, 20° flip angle) of a 71-year-old woman with DAVF at the left cavernous sinus. There is an early depiction of the bilateral cavernous sinuses (arrows) at the early arterial phase (left). The bilateral superior ophthalmic veins (arrowheads) are dilated during the arterial (middle) and late arterial phase (right). The bilateral internal maxillary arteries are well visualized (small arrows). Retrograde cortical venous drainage is via the left cerebral cortical veins (circle). Both readers judged that this DAVF was primarily fed by the internal maxillary artery, that the cavernous sinus was the fistula site, and that venous drainage was type 2. B, Anteroposterior (upper) and lateral (lower) projections of DSA (left) and 4D-CE-MRA (right) images in the arterial phase in the patient in A. DSA shows an arteriovenous shunt (arrow) at the left cavernous sinus. It is supplied by branches from the left internal maxillary (arrowhead) and middle meningeal arteries (small arrow). The right cavernous sinus (small arrowhead) is depicted via the intercavernous sinus. Retrograde cortical venous drainage is via the left cerebral cortical veins (circle). 4D-CE-MRA also depicts the main arterial feeders (arrowhead, small arrow), the fistula site (arrow), and the venous drainage pattern (circle).