Usefulness of arterial spin labeling imaging, which contributed to the early detection of cerebellitis complicated by clinically mild encephalitis/encephalopathy with a reversible splenial lesion: Lessons from three cases.

BACKGROUND: Cerebellitis is a rare complication of clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS); however, MERS with cerebellitis is associated with a higher risk of neurological sequelae in comparison to MERS alone. Although the disease is difficult to diagnose by conventional MRI in the early disease phase, arterial spin labeling (ASL), a noninvasive MRI perfusion technique using magnetically-labeled arterial blood water protons, is considered promising. CASE REPORT: We experienced three cases of MERS with cerebellitis. Diffusion-weighted imaging showed a high-intensity lesion at the splenium of the corpus callosum. ASL showed increased blood flow in the cerebellum in all three cases, despite cerebellar symptoms being inapparent or difficult to notice in the early phase of disease in all cases. Patients received methylprednisolone pulse therapy and intravenous immunoglobulin from the early phase of the disease and recovered without neurological sequelae. DISCUSSION: ASL magnetic response imaging simultaneously showed an area of hyperperfusion in the cerebellum. At the same time, the apparent diffusion coefficient of the splenial lesion was decreased in all three cases. The successful diagnosis of cerebellitis in the acute phase led to early therapeutic intervention, which may be important for this condition. We report the usefulness of ASL and review the relevant literature on MERS with cerebellitis.

Diagnostic value of single photon emission computed tomography (SPECT) for patients with non-herpetic acute limbic encephalitis.

To evaluate the diagnostic value of SPECT (single photon emission computed tomography) brain blood flow imaging for patients with non-herpetic acute limbic encephalitis (NHALE). A retrospective review of three patients who had clinical symptoms compatible to NHALE and were positive for anti-N-methyl-d-aspartate-type glutamate receptor (GluRε2) antibody. The patients consisted of a 6-year-old female, a 10-year-old female and a 13-year-old male, all of whom had limbic symptoms and were anti-GluRε2 antibody-positive. In all cases, brain MRI failed to detect any abnormality, but SPECT brain blood flow imaging was able to detect blood flow changes. All three cases showed some abnormality in their brain waves, and one of them also developed epilepsy. SPECT brain blood flow imaging may therefore be helpful for diagnosing NHALE which can lead to the development of either epilepsy or cognitive impairment.

[Ictal arterial spin labeling MRI findings in two cases of acute confusional migraine].

Arterial spin labeling (ASL) is a magnetic resonance imaging (MRI) technique that enables visualizing of cerebral blood flow without need of a contrast medium. In recent years, there have been reports from outside Japan related to ASL use in migraine attacks. We report two cases of acute confusional migraine (ACM) in children. At time of confusion, ASL imaging showed reduced blood flow: for the first patient, in both cerebral hemispheres from the occipital lobe through the parietal lobe to the temporal lobe; for the second patient, throughout the left cerebral hemisphere. T1-, T2-, diffusion-weighted images, and fluid attenuation inversion recovery (FLAIR) images indicated normal results. Subsequent ASL re-examinations for both cases showed recovery from reduced blood flow. In our view, ACM can be characterized by a reduction in blood flow not limited to the occipital lobe but across wide regions of the cerebral hemisphere. We consider ASL to be helpful in the difficult differentiation of ACM from other disturbances of consciousness, in addition to enabling repeated examinations without the risks associated with single-photon emission computed tomography (SPECT) concerning radiation exposure or with contrast MRI concerning contrast media use.