Acute Stroke Evaluated by Time-to-Peak Mapping during Initial and Early Follow-up Perfusion CT Studies
Jürgen R. Reichenbach
,a,
Joachim Röthera,
Lars Jonetz-Mentzela,
Michael Herzaua,
Anke Fialaa,
Cornelius Weillera and
Werner A. Kaisera
a From the Institute for Diagnostic and Interventional Radiology (J.R.R., L.J-M., M.H., W.A.K.) and the Department of Neurology (J.R., A.F., C.W.), Friedrich-Schiller University, Jena, Germany.
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FIG 1. Patient 6.
A, Initial native CT scan shows standardized circular ROIs, which were manually placed in both hemispheres in the vascular territories of the ACA, MCA, PCA, the basal ganglia region, and the thalamus.
B, Enhancement-versus-time curves of ROIs 1 and 2 located symmetrically in the anterior vascular territory of the MCA in the ischemic and healthy areas, respectively. Note the strong enhancement peak indicating the passage of the compact contrast bolus in the normal area (ROI 2). Conversely, the time course of the contralateral ROI (ROI 1) shows a markedly delayed and slow enhancement, indicating hypoperfusion.
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FIG 2. Initial native CT scans and corresponding time-to-peak parameter maps. The maps are color-coded with values ranging from 5 to 40 seconds.
A, Patient 6: 62-year-old woman who presented 40 minutes after onset of left hemiparesis. The CT scan is normal. Note the clear demarcation of the diseased area in the right hemisphere, corresponding to the right ACA and MCA territories, including the basal ganglia on the parameter map.
B, Patient 17: 77-year-old woman who presented 40 minutes after onset of somnolence and left hemiparesis. The native CT scan is normal. The parameter map shows an area of delayed perfusion in the territory of the right MCA.
C, Patient 1: 60-year-old man who had a normal CT scan 2.8 hours after onset. The time-to-peak map depicts a large perfusion deficit in the left MCA territory, including the basal ganglia.
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FIG 3. Patient 10: initial and follow-up examinations.
A, 2 hours 50 minutes after onset.
B, 30 hours after onset, during therapy with heparin. The patient suffered from a large infarct in the left hemisphere with global aphasia and right hemiparesis. The first native CT scan (A) reveals only discrete cortical hypodensity and effacement of cortical sulci in the ischemic hemisphere. In contrast, the time-to-peak map clearly shows the extent of the affected brain area, which corresponds strongly to the hypodensity seen on the CT scan in the follow-up study (B). The time-to-peak map shows tissue reperfusion 30 hours later. A large MCA infarction developed despite recanalization.
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