Combined SPECT and diffusion-weighted MRI as a predictor of infarct growthin acute ischemic stroke

In acute ischemic stroke, the infarcted core is surrounded by a zone of tis sue that has decreased perfusion. Some of this tissue may be salvaged by pr ompt, effective treatment. Diffusion-weighted MRI is sensitive in detecting the infarcted tissue, whereas SPECT also detects the hypoperfused tissue a round the infarcted core. We studied the potential of combined diffusion-we ighted MRI and SPECT to predict infarct growth and clinical outcome in pati ents not receiving thrombolytic treatment. Methods: Sixteen patients with a cute stroke were examined consecutively with diffusion-weighted MRI and Tc- 99m-ethyl cysteinate dimer (Tc-99m-ECD) SPECT within 24 h of the onset of s ymptoms. Follow-up diffusion-weighted MRI was performed on the second day a nd after 1 wk. The volumes of infarcted and hypoperfused brain tissue were measured from diffusion-weighted MRI and SPECT, respectively. The volume di fference between the hypoperfused and infarcted tissue on the first day was compared with the possible increase in infarct volume during the follow-up . Each patient's neurologic status was assessed with the National Institute s of Health Stroke Scale (NIHSS). Results: The volume of infarcted tissue i ncreased from 48 +/- 54 cm(3) (mean +/- SD) on the first day to 88 +/- 93 c m(3) on the second day (P = 0.001) and to 110 +/- 121 cm(3) at 1 wk (P = 0. 001). The volume of hypoperfused tissue on the first day was significantly greater than the infarct volume (102 +/- 135 cm(3); P = 0.001). The volume difference between the hypoperfused and infarcted tissue on the first day c orrelated significantly with the infarct growth between the first day and 1 wk (r = 0.71; P < 0.01). Between the first day and 1 wk, the increase of t he infarct volume correlated significantly with the change in the NIHSS (r = 0.54; P < 0.05). Conclusion: A large hypoperfusion zone around the infarc t core in the acute phase of ischemic stroke predicts the infarct growth du ring the first week, and this correlates significantly with the change in t he neurologic status of the patient. Combined diffusion-weighted MRI and SP ECT performed within 24 h after the onset of symptoms can be useful in the evaluation of acute stroke to predict infarct growth.