Early reperfusion in the 'spectacular shrinking deficit' demonstrated by single-photon emission computed tomography

The "spectacular shrinking deficit" (SSD) refers to a syndrome of profound hemispheric ischemia that resolves rapidly over hours to days, leaving patients with minimal residual neurologic deficits. The SSD is postulated to result from rapid embolic lysis, fragmentation, and migration along the internal carotid/middle cerebral artery axis, leading to restored tissue perfusion before irreversible tissue damage has occurred. We performed serial single-photon emission computed tomographic (SPECT) cerebral perfusion measurements during the first 48 hours in 36 patients admitted with major hemispheric ischemia, to compare the cerebral perfusion changes between patients who developed SSD (n = 5) and those who did not (n = 31). The two groups were similar for severity of neurologic deficit, time of SPECT study, and size of perfusion defect on the SPECT images. Patients with SSD were younger (p = 0.02, Mann-Whitney U), demonstrated significantly greater tissue reperfusion during the first 48 hours (p < 0.01), and had smaller infarcts on CT (p = 0.02). This syndrome provides an opportunity to understand the mechanism by which early reperfusion may result in early tissue salvage and clinical recovery.