Diagnostic Imaging of Higher Brain Dysfunction in Patients With Adult Moyamoya Disease Using Statistical Imaging Analysis for [¹²³I]Iomazenil Single Photon Emission Computed Tomography

Abstract

[123I]iomazenil (IMZ) is a specific radioligand for the central benzodiazepine (BZ) receptor that may be useful as a marker of cortical neuron loss after cerebral ischemia using single photon emission computed tomography (SPECT). This study used statistical imaging analysis for IMZ-SPECT to investigate the relationship between higher brain dysfunction and cortical neuron loss in the medial frontal lobes, to establish a confirmatory diagnosis of higher brain dysfunction in patients with adult moyamoya disease. IMZ-SPECT was estimated by three-dimensional stereotactic surface projections (3D-SSP). Cortical neuron loss was analyzed using the stereotactic extraction estimation (SEE) method (level 3: gyrus level) for 3D-SSP Z-score maps (Z-score >2). Extent of pixels with significant reduction of BZ receptor density within the target gyri (i.e. bilateral medial frontal gyri [MFGs] and anterior cingulate gyri [ACGs]) was calculated. In 6 patients with higher brain dysfunction, significant cortical neuron loss was observed in the bilateral MFGs in 4 patients, unilateral MFG in 1 patient, and bilateral ACGs in 2 patients. In 12 patients without higher brain dysfunction, no significant cortical neuron loss was observed in the bilateral MFGs or ACGs, and mild loss was observed in the bilateral MFGs in 2 patients, unilateral MFG in 4 patients, and unilateral ACG in 2 patients. Long-standing mild hemodynamic ischemia in the anterior circulation of patients with adult moyamoya disease could lead to incomplete brain infarction within the medial frontal lobes. Statistical imaging analysis using 3D-SSP and SEE methods for IMZ-SPECT could demonstrate significant cortical neuron loss in the bilateral frontal medial cortices involving MFG and/or ACG which correlate with higher brain dysfunction in patients with adult moyamoya disease.

Impact of posterior cerebral artery involvement on long-term clinical and social outcome of pediatric moyamoya disease

“…Interestingly, Nakagawara et al speculated that long-standing mild hemodynamic ischemia in the medial frontal lobe could lead to selective neuron loss detected by SPECT imaging with benzodiazepine receptor radioligand, and cognitive dysfunction in patients with moyamoya disease. 26 Our study has some limitations. First, the result of our multivariate analysis has a relatively large confidence interval, which can be attributed to the limited number of cases.…”

Cognitive Function of Patients with Adult Moyamoya Disease

“…However, difficulty with social independence accompanied by cognitive impairment has recently been recognized as an important unsolved social issue faced by patients with adult moyamoya disease. [7] These patients are physically independent in daily life, but economically dependent because cognitive impairment leads to difficulty obtaining vocational skills. Here, we define the status of these patients as "difficulty with social independence."…”

Moyamoya Disease Presenting as Transient Amnesia with Cortical Blindness

“…The neuropsychological or cognitive problems related to MMD were previously reported in the literature. 4,5 Patients with MMD are more likely to have neuro-psychological sequelae. In general, cognitive impairments associated with MMD have been described as neuro-psychologic sequelae that occur after stroke.…”

“…5 However, recently some adult cases have been reported and suggest that neurocognitive disorders can occur without radiological evidence of major strokes. 4 The association between brain dysfunction and persistent frontal lobe hemodynamic compromise can be demonstrated using single-photon emission computed tomography, even if no cerebral infarction has occurred. 4 However, to our knowledge, these presented problems, which mimic Dide-Botcazo syndrome, may not have been reported in previous literature.…”

“…4 The association between brain dysfunction and persistent frontal lobe hemodynamic compromise can be demonstrated using single-photon emission computed tomography, even if no cerebral infarction has occurred. 4 However, to our knowledge, these presented problems, which mimic Dide-Botcazo syndrome, may not have been reported in previous literature. Dide-Botcazo syndrome is a rare clinical syndrome characterized by a combination of cortical blindness with anosognosia for blindness, retro-anterograde amnesia, topographic agnosia, alexia, and astereognosis secondary to bilateral occipital cortex lesions which also involve the inferior-medial temporal lobe structure.…”