Clinical Applications of 2-D Dynamic Contrast-enhanced MR Subtraction Angiography in Neurosurgery -- Preliminary Results

Objectives: Advances in MR hardware performance and imaging techniques have enabled us to perform sub-second frame rate contrast enhanced MR angiographies as a clinical routine, resulting in subtraction angiographies with temporal resolutions similar to those obtained by conventional DSA. In this manuscript, we describe the technique of 2-D dynamic contrast-enhanced MR subtraction angiography and its possible applications in neurosurgery.

Methods: A T (1)-weighted gradient-echo sequence with short TR and TE values was performed during the intravenous bolus application of MR contrast media. This sequence had a temporal resolution of up to 0.34 seconds per image and was performed in 28 patients harbouring arteriovenous malformations (n = 12), dural AV fistulas (n = 3), meningiomas (n = 8), glomus tympanicum or jugulare tumours (n = 3), and haemangioperizytomas (n = 2). Arterial digital subtraction angiography (DSA) was performed in all patients and compared to the MRA sequences with respect to differentiation into early, late arterial and venous phases, detectability of normal vessels, detection of the pathology, feeding arteries, capillary blush, early draining veins, and hyper-vascularization.

Results: In all 28 investigated cases and all pathological entities separation of early and late arterial phases, capillary phases, early and late venous phases was possible. The proximal portions of the major cerebral arteries, the capillary blush and the venous anatomy including the tributaries to the large sinuses could be well defined and correlated well with the gold standard, i. e. DSA.

Conclusions: Dynamic contrast enhanced MR angiography will prove helpful in 1) the follow-up of AVMs since early venous drainage can be visualised; 2) the demonstration of dural AVF, which can be recognised as an early filling of a dural sinus during the early arterial phase; and 3) the characterisation of the degree of vascularisation of brain tumours.