Normal Structures in the Intracranial Dural Sinuses: Delineation with 3D Contrast-enhanced Magnetization Prepared Rapid Acquisition Gradient-Echo Imaging Sequence

Images from the case of a 40-year-old woman with headaches who had normal results of an MR imaging study.

A, Axial source image acquired with a 3D contrast-enhanced MPRAGE sequence shows numerous small filling defects (arrowheads), consistent with arachnoid granulations, aligned along the lateral margin of the superior sagittal sinus.

B, Sagittal reconstruction image obtained with a 3D contrast-enhanced MPRAGE imaging sequence shows an array of arachnoid granulations within the superior sagittal sinus.

Images reveal arachnoid granulations in a 54-year-old man with headaches who had normal results of an MR imaging study.

A, Sagittal reconstruction image obtained from 3D contrast-enhanced MPRAGE imaging sequence shows a large CSF-isointense filling defect, consistent with an arachnoid granulation (black arrows), at the junction point of the vein of Galen and straight sinus. Note also the presence of smaller arachnoid granulations within the superior sagittal sinus (white arrowheads).

B, Axial T2-weighted MR image shows the defect seen in A as a discrete, focal CSF-isointense filling defect within the straight sinus.

Image reveals arachnoid granulation in a 55-year-old woman with seizures who had normal results of an MR imaging study. Sagittal reconstruction image obtained with a 3D contrast-enhanced MPRAGE sequence shows a large CSF-isointense pouchlike focal filling defect (arrowheads) in the straight sinus. Note that this structure extends to the adjacent CSF space (asterisk) via the orifice opening to the subarachnoid space (small arrows).

Images reveal invagination of brain tissue into the dural sinus in a 32-year-old woman with pituitary hormonal abnormalities who had otherwise normal results of an MR imaging examination.

A, Source image acquired with a 3D contrast-enhanced MPRAGE sequence shows a focal filling defect in the right transverse sinus (arrowheads) that is isointense to brain parenchyma.

B, Reconstruction image obtained in an oblique sagittal plane shows that the structure seen in A is contiguous with brain parenchyma (arrowhead), consistent with invagination of brain tissue into the dural sinus.

Reconstruction image from a 3D contrast-enhanced MPRAGE image shows relationship of intracranial veins to arachnoid granulation in a 35-year-old man with normal results of an MR imaging study. The posteroinferior cerebellar vein (arrows) is seen to enter into a CSF-isointense structure (arrowheads), consistent with an arachnoid granulation.

Image reveals association of intracranial veins and arachnoid granulations in a 41-year-old man with normal results of an MR imaging examination. Axial source image acquired with a 3D contrast-enhanced MPRAGE sequence shows multiple venous tributaries (small arrows), including the vein of Labbé (large arrow), entering into an arachnoid granulation (arrowhead) within the transverse sinus.

Image shows appearance of septum within dural sinus in a 68-year-old woman with normal results of an MR imaging examination. Reconstruction image from a 3D contrast-enhanced MPRAGE image shows a linear structure (arrows), consistent with a septum within the straight sinus.

Image shows septa within dural sinuses in a 39-year-old man with normal results of an MR imaging study. Axial source image from a 3D contrast-enhanced MPRAGE image shows curvilinear septa (arrows) that have intermediate signal intensity in both transverse sinuses. The septa seen in this study were usually smooth, thin, and not limited to the center of the sinus.

Comparison of 2D time-of-flight MR venograms and 3D contrast-enhanced MPRAGE images of a 37-year-old woman with postpartum dural sinus thrombosis.

A, 2D time-of-flight maximum intensity projection MR venogram shows lack of flow-related enhancement in superior sagittal sinus (arrows) and straight sinus (arrowheads). Note that by using this technique, the thrombosis is inferred by absence of a finding (ie, lack of flow-related enhancement) rather than by direct visualization of the thrombus.

B, Sagittal reconstruction image obtained from a 3D contrast-enhanced MPRAGE image directly shows thrombus in the straight sinus and superior sagittal sinus (large arrows). The thrombus is also seen to extend into the adjacent vein of Galen (small arrows), have irregular margins, and produce irregular contrast enhancement of the inferior sagittal sinus (arrowheads), which were findings that were not seen in cases showing arachnoid granulations.