Prospective value of perfusion and X-ray attenuation imaging with single-photon emission and transmission computed tomography in acute cerebral ischemia

Background and Purpose-The aim of the present study was to test the hypothe sis that perfusion single-photon emission computed tomography (SPECT), carr ied out in addition to transmission computed tomography (TCT), improves the predictive value of brain imaging within the therapeutically relevant time window after acute cerebral ischemia. Methods-Using TCT and [Tc-99m]ethyl cysteinate dimer (ECD)-SPECT within 6 h ours after symptom onset, we examined 108 patients (44 women, 64 men; mean age 65 +/- 13 years) with acute ischemic stroke attributed to the territory of the middle cerebral artery (MCA). In each case, 3 experts prospectively evaluated the early SPECT and TCT images. We correlated these ratings with follow-up TCT findings for the final infarction as well as with clinical o utcome (Scandinavian Stroke Scale, Barthel index, Modified Rankin Scale) af ter 30 and 90 days. Results-Severe activity deficits on SPECT; not caused by local atrophy on T CT, were the best predictors (positive predictive value [PPV ]94%, 95% CI 8 9% to 99%; negative predictive value [NPV] 90%, 95% CI 78% to 100%; P <0.00 1) for evolving cerebral infarction. Complete MCA infarctions were predicte d with significantly higher accuracy with early SPECT (area under receiver operating characteristic curve [AUC] index 0.91) compared with early TCT (A UC index 0.77) and clinical parameters (AUC:index 0.73, P <0.05). Logistic regression analysis:revealed I independent predictor for completed MCA terr itory infarction: SPECT activity deficits in the corresponding areas (PPV 8 8%, 95% CI 65% to 100%; NPV 96%, 95% CI 92% to 100%; P <0.001). Furthermore , death after stroke was optimally predicted by [Tc-99m]ECD-SPECT. Clinical outcome up to 90 days after the stroke event best correlated with the degr ee of activity deficits in early SPECT (r=0.53, P <0.001). Conclusions-[Tc-99m]ECD brain perfusion SPECT that completes TCT definitely improves the predictive value of brain imaging after acute cerebral ischem ia. Thus, the combined imaging of brain edema and of cerebral perfusion ear ly after stroke is recommended for clinical use.