Fig 1.
Tissue TACs of the hypoperfused and healthy tissue in the phantom data.
In green is the TAC of the healthy tissue. In red is the TAC of the hypoperfused tissue without arrival delay of contrast agent (the original phantom data). The blue curves are the shifted TACs of the hypoperfused tissue of each individual phantom (n = 7). Each curve has a different amount of time shift (from left to right:1, 3, 5, 7, 9, 11 and 13 seconds), and thus arrival delay of contrast agent, relative to the TAC of the healthy tissue (green). With increasing time shift the proportion of the TAC that is truncated increases.
Table 1.
Scanner and settings.
Fig 2.
Examples of tissue time attenuation curve truncation with normal AIF and VOF.
Normal AIF and VOF for the CTP data of patient 19 (left) and corresponding truncated tissue TAC for the 48 seconds acquisition data of the same patient (right). These figures illustrates that an acquisition time of 48 seconds can be insufficient to capture the complete outwash of contrast agent from the ischemic tissue.
Fig 3.
Examples of AIF and VOF truncation.
Example of normal AIF curve with truncated VOF curve (left).Example of truncated AIF and VOF curves (right). For both examples longer acquisition time is needed to capture the complete in-wash and outwash of contrast agent.
Fig 4.
Examples of complete and incomplete tissue time attenuation curves.
Complete tissue time attenuation curves from patient 6 (upper left) and patient 24 (upper right). Truncated tissue time attenuation curve from patient 7 (bottom left) and 3 (bottom right). The AIF and VOF of patients 7 and 3 were complete.
Fig 5.
Summary Maps from original phantom data.
CTP summary map for all slice locations resulting from analysis of the original CTP phantom data without arrival delay of contrast agent.
Fig 6.
Ischemic core and penumbra from phantom data.
This figure shows the effect of shifting TACs of the hypoperfused tissue relative to the TACs of the healthy tissue, and thus simulating contrast arrival delay, on ischemic core and penumbra determination.
Table 2.
Patient demographics, clinical characteristics, and the measured perfusion defect volumes.
Fig 7.
CTP summary maps from patient 19.
CTP summary map for the 48 seconds acquisition data with truncated tissue TAC (left). Corresponding CTP summary map for the 210 seconds acquisition data with complete TACs (right). Red: ischemic core, green: ischemic penumbra (See Fig. 2 for corresponding TAC curves).
Table 3.
Difference in volumes between the extended (210 s) and standard (48 s) acquisition time (extended-standard).