Clinical value of perilesional perfusion deficit measured by Technetium-99m-ECD single-photon emission computed tomography in hypertensive intracerebral hemorrhage

Pathological and experimental studies indicate the existence of a "penumbra" of progressive tissue damage and edema in regions immediately surrounding a hematoma in patients of intracerebral hemorrhage (ICH). This zone of oligemia surrounding ICH has a potential for perfusion recovery. Improved understanding of the pathophysiology of perilesional blood flow changes and brain injury after ICH may result in improved treatment strategies. The aim was to study perilesional blood flow changes in ICH by perfusion deficit (PD) measured by single-photon emission computed tomography (SPECT) and to correlate it with the severity of ICH and outcome. Forty-four patients of computed tomography (CT) documented nonlobar deep ICH suggestive of hypertensive hematoma of <7 days duration were subjected to ^99mTc-ethylene diacetate SPECT scans of the brain. Patients with significant midline shift (0.5 cm) or global blood flow reduction were excluded from the analysis. SPECT scan of the brain was analyzed by segmental analysis, a semi-quantitative method of cerebral blood flow. A difference of radiotracer uptake of >10% between the region of interest of ICH cases and the ratio between the two ROI below 0.9 was taken as a significant PD. A correlation of PD was analyzed with that of various parameters such as the severity of stroke, duration from onset of ictus, and imaging including CT scan of the brain and SPECT scan. A statistically significant difference in the percentage of radiotracer uptake on comparison of ipsilateral and contralateral to ICH (P < 0.001) was observed, suggesting a significant hypoperfusion in the perilesional area in patients with ICH. A statistically significant correlation was noted between the severity of stroke and PD indicated by various parameters such as the National Institutes of Health Stroke Scale (NIHSS) score at admission (r = 0.328, P = 0.016), Glasgow Coma Scale (GCS) score at admission (r = -0.388, P = 0.005), and ICH score at admission (r = 0.314, P = 0.020). This study demonstrated more severe hypoperfusion in clinically severe ICH which is a possible explanation of poor outcomes in severe ICH cases. We observed hypoperfusion on SPECT study in 25 of 34 (73.5%) patients with subacute ICH and 5 of 10 patients (50%) with acute ICH. The mean time from the onset of ictus to SPECT scan done was 5.04 ± 1.75 days with a range of 1-7 days, suggesting the persistence of hypoperfusion in subacute stages too. This finding may be of clinical importance for identifying the salvageable area surrounding ICH for any possible intervention in future to improve the outcome. This study demonstrates that perilesional PD occurs in acute and subacute cases of ICH. This hypoperfusion is possibly time related and appears to be more severe in patients having major ICH with poor clinical and imaging parameters. This area of hypoperfusion or ischemic penumbra is a potential site for perfusion recovery to improve clinical outcomes and to reduce long-term neurological deficits.