Korean J Radiol.  2002 Sep;3(3):163-170. 10.3348/kjr.2002.3.3.163.

Multiphasic Perfusion CT in Acute Middle Cerebral Artery Ischemic Stroke: Prediction of Final Infarct Volume and Correlation with Clinical Outcome

• Yi CA
• Na DG
• Ryoo JW
• Moon CH
• Byun HS
• Roh HG
• Moon WJ
• Lee KH
• Lee SJ

• KMID: 754058
• DOI: http://doi.org/10.3348/kjr.2002.3.3.163

Abstract

OBJECTIVE
To assess the utility of multiphasic perfusion CT in the prediction of final infarct volume, and the relationship between lesion volume revealed by CT imaging and clinical outcome in acute ischemic stroke patients who have not undergone thrombolytic therapy.
MATERIALS AND METHODS
Thirty-five patients underwent multiphasic perfusion CT within six hours of stroke onset. After baseline unenhanced helical CT scanning, contrast-enhanced CT scans were obtained 20, 34, 48, and 62 secs after the injection of 90 mL contrast medium at a rate of 3 mL/sec. CT peak and total perfusion maps were obtained from serial CT images, and the initial lesion volumes revealed by CT were compared with final infarct volumes and clinical scores.
RESULTS
Overall, the lesion volumes seen on CT peak perfusion maps correlated most strongly with final infarct volumes (R2=0.819, p<0.001, slope of regression line=1.016), but individual data showed that they were less than final infarct volume in 31.4% of patients. In those who showed early clinical improvement (n=6), final infarct volume tended to be overestimated by CT peak perfusion mapping and only on total perfusion maps was there significant correlation between lesion volume and final infarct volume (R2=0.854, p=0.008). The lesion volumes depicted by CT maps showed moderate correlation with baseline clinical scores and clinical outcomes (R=0.445-0.706, p<=0.007).
CONCLUSION
CT peak perfusion maps demonstrate strong correlation between lesion volume and final infarct volume, and accurately predict final infarct volume in about two-thirds of the 35 patients. The lesion volume seen on CT maps shows moderate correlation with clinical outcome.

Keyword

Brain, ischemia; Computed tomography (CT), helical

MeSH Terms

Acute Disease
Adult
Aged
Aged, 80 and over
Blood Volume/*physiology
Cerebrovascular Circulation/physiology
Contrast Media
Female
Human
Infarction, Middle Cerebral Artery/*physiopathology/*radiography
Male
Middle Age
Middle Cerebral Artery/*physiopathology/*radiography
Predictive Value of Tests
Prognosis
Retrospective Studies
Tomography, X-Ray Computed

Figure

• 

  Fig. 1 Overall correlation between initial lesion volume and final infarct at unenhanced CT, and on CT peak and total perfusion maps. The relationship between initial lesion and final infarct volume was strongest on CT peak perfusion maps (R2=0.819), followed by CT total perfusion maps (R2=0.797) and unenhanced CT (R2=0.641). CT peak perfusion maps showed that initial lesion volume was slightly less than final infarct volume (slope of regression line=1.016), while CT total perfusion maps and unenhanced CT showed it as significantly less (slope of regression line=1.246 and 1.523, respectively).

• 

  Fig. 2 Correspondence between lesion volume at CT peak perfusion mapping and final infarct volume in a 31-year-old female who underwent multiphasic perfusion CT five hours after the onset of stroke symptoms. Unenhanced CT (A) shows diffuse parenchymal hypodensity and loss of cortex/white matter distinction (arrows) in left MCA territory. Lesion size at unenhanced CT is similar to that of the hypoperfused lesion (arrows) seen on CT peak (B) and total perfusion maps (C), indicating no mismatch between these two maps or between unenhanced CT and CT maps. Follow-up CT images (D) obtained 3 days after initial CT show a significant mass effect and infarction edema in the left hemisphere. Seven days after the onset of stroke, the NIHSS score was slightly aggravated (increase of 4).

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  Fig. 3 Overestimation of lesion volume on CT peak perfusion map in a 75-year-old female who underwent multiphasic perfusion CT 2 1/2 hours after the onset of stroke symptoms. Unenhanced CT (A) reveals no parenchymal hypodensity. The CT peak perfusion map (B), though not the total perfusion map (C), depicts a diffuse hypoperfused lesion (arrows) in left MCA territory, suggesting abundant delayed collateral flow. This case shows significant mismatch between the CT peak perfusion map and unenhanced CT, as well as between CT peak perfusion and total perfusion maps. Follow-up CT (D) performed two days after initial CT, shows little mass effect of the ischemic lesion and a smaller infarction than the hypoperfused lesion seen on the CT peak perfusion map. Seven days after the onset of stroke, the NIHSS score showed no significant change (decrease of 1).

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