Multiple occipital defects caused by arachnoid granulations: Emphasis on T2 mapping

Figure 1 Multiple arachnoid granulations (arrows) in a 56-year-old man. Axial noncontrast computed tomography on soft-tissue windows (A) and bone windows (B) showed occipital multiple osteolytic lesions adjacent to the transverse sinus.

Figure 2 Multiple arachnoid granulations (arrows) in a 56-year-old man. A-C: Sagittal T1-weighted image (T1WI) (A) showed hypointensity relative to the brain, axial (B) and sagittal (C) T2-weighted image showed hyperintensity relative to the brain, with a banded lower signal most likely representing the intra-arachnoid granulations (AGs) collagenous connective tissue; D: Axial fluid attenuated inversion recovery image demonstrated complete suppression of intra-AG fluid; E, F: Axial diffusion-weighted imaging (E) showed no restricted diffusion. Sagittal postcontrast T1WI (F) showed no gadolinium enhancement.

Figure 3 Multiple arachnoid granulations (arrow) in a 56-year-old man. A: Coronal three-dimensional fast imaging employing steady state acquisition showed that the subarachnoid cavity communicated with a large arachnoid granulation (AG); B, C: Sagittal T2-mapping demonstrated T2 relaxation times of intra-AG contents paralleled that of cerebrospinal fluid in the ventricles and adjacent subarachnoid spaces; D: Single photon emission computed tomography with ^99mTc-Methyl diphosphonate revealed no increased radiotracer accumulation.