Positional Brain Single-Photon Emission Computed Tomography Findings in a Case of Limb-Shaking Syndrome.

An 84-year-old man, who presented lower limbs limb-shaking syndrome at orthostatism lasting a few seconds, was referred in our stroke unit. Magnetic resonance imaging showed an acute infarction in the right thalamus and the insular cortex, left extracranial carotid stenosis at 80%, and low flow in the right middle cerebral artery but did not explain limb-shaking syndrome symptomatology. We performed comparative positional brain perfusion single-photon emission computed tomography (SPECT), in the upright and in the supine position, to explore and localize hypoperfusion-endangered brain structures that may be involved in the presenting symptoms. Brain perfusion SPECT showed deep hypoperfusion in bilateral carotid territories in the upright position in favor of a hemodynamic mechanism, on which blood pressure was maintained higher to avoid hypoperfusion and the patient remained supine for a longer period of time than in the usual support. Late postoperative brain perfusion SPECT after left endarterectomy did not show significant abnormalities. Limb-shaking syndrome may be related to a transient decrease in blood pressure and cerebral blood flow caused by postural changes. Positional brain perfusion SPECT seems to be helpful to improve clinical care. Positional brain perfusion SPECT should be discussed in the acute phase of stroke and if there are involuntary movements.