Double-doughnut Sign: An Interesting Imaging Finding in Dengue Encephalitis

Dengue encephalitis featuring “double-doughnut” sign - A case report

“…altered sensorium and seizures. The prognosis is similar as the patients achieved full recovery in both instances, however, our case had some delay to achieve the improvement owing to the severity of neurological insult at the beginning [ 20 ]. Similar MRI findings have been reported in cases of Japanese encephalitis [ 8 , 21 ].…”

“…They mostly report involvement of bilateral thalamus, brainstem, cerebellum, basal ganglia, medial temporal lobes and cortical and cerebral white matter [ 14 , 15 ]. The “double-doughnut” sign in dengue encephalitis is characterized by symmetrical T2/FLAIR high signal intensity area in bilateral thalami with restriction of diffusion on DWI and ADC and blooming in central region in gradient echo sequence due to hemorrhagic residues and have only been reported in few reports and case series [ [16] , [17] , [18] , [19] , [20] ]. Dengue virus inflicts direct neuronal injury leading to cerebral edema and hemorrhage secondary to vascular leak, which usually involves bilateral basal ganglia and thalamus complex and manifests neuro-radiologically as “double-doughnut” sign [ 14 ].…”