Time-resolved 3D Rotational Angiography (4D DSA) of the Lenticulostriate Arteries: Display of Normal Anatomic Variants and Collaterals in Cases with Chronic Obstruction of the MCA.

Abstract

The lenticulostriate arteries (LSA) and other perforators may play arole for collateral supply in cases with ischemia due to stenosis or occlusions of the middle cerebral artery (MCA). Purpose of this case series was to evaluate the potential of time-resolved 3D rotational angiography data sets (4D DSA) for detailed visualization of anatomic variants of LSA feeders and for display of local collaterals involving the LSA in cases with chronic MCA obstruction. Multiplanar and volume rendering reconstructions of 4D DSA data were computed in addition to standard postprocessing in 24patients who had indications for 3D rotational angiography (3DRA) of the internal carotid artery (ICA) without pathologies of the ICA, middle cerebral artery (MCA) and anterior cerebral artery (ACA) main stems (n= 18) or with stenosis or chronic occlusion of the MCA (n= 6). For acquisition of 3DRA, we used amodified digital subtraction angiography (DSA) image acquisition protocol with an extended rotation angle of 260° and aprolonged scan time of 12 s on aSiemens Axiom Artis Zee biplane neuroangiography equipment. The 4D reconstructions of existing 3DRA data were computed on adedicated workstation. Origin and course of LSA and other perforators were analyzed according to coronal multiplanar reconstructions (MPRs) with slice thicknesses between 6 and 28 mm. In all cases 4D reconstructions of the LSA were technically feasible and evaluable. As expected, origin and course of LSA showed awide range of variations: The most common pattern was acommon trunk dividing into multiple ascending branches originating from the proximal M1 (n= 5) or the proximal A1segment (n= 4). Alternatively, 8patients showed several individual branches that directly originated from the proximal M1segment of the MCA and occasionally from the A1segment of the ACA. In patients with M1stenosis or occlusion, 4 out of 6cases had local collaterals with involvement of proximal LSA trunks and anetwork parallel to the obstructed vessel segment. The 4D reconstructions were found to be equivalent (n= 16) or superior to 3D reconstructions (n= 8). The 4D DSA reconstructions provide areliable display of normal LSA variants and connections to local collateral networks in cases with chronic MCA obstruction. The possibility to select acorrect angiographic phase is advantageous compared to 3D DSA.