Article Figures & Data
Figures
- Fig 1.
ROIs in image sections standardized and summed by using 3D-SSPs.
- Fig 2.
Comparisons of qualitative rCVR with quantitative rCVR (%Hem) calculated by using the IMP autoradiographic method. Significant correlation was observed between these two values. A plot of the relationship between these two values revealed four groups of results: 1) those with reduced rCVR (true-positive), 2) those in which only the quantitative method identified reduced rCVR (false-negative), 3) those without reduced rCVR (true-negative), and 4) those considered reduced rCVR only by the qualitative method (false-positive). Dashed horizontal and vertical lines denote the mean − 2 SDs of the rCVR values obtained in healthy volunteers by using the quantitative method or the qualitative method.
A, AIHem change.
B, FIHem−Cbl change.
- Fig 3.
Example of a false-positive result. The same color scale is used to display quantitative rCBF images calculated by using the IMP autoradiographic method at resting state and with the acetazolamide challenge. This patient had a symptomatic occluded ICA on the right side. After the administration of acetazolamide, the patient’s rCBF in the MCA territory increased by 10.3 mL/100 g/min on the right side and by 26.4 mL/100 g/min on the contralateral side. This increase was asymmetrical, with the qualitative assessment defining rCVR as reduced (AIHem change = −28.3), although %Hem on the occluded side, as determined quantitatively, showed a normal flow response of 31.0%.
- Fig 4.
Example of a false-negative result. The same color scale is used to display quantitative rCBF images calculated by using the IMP autoradiographic method at the resting state and with the acetazolamide challenge. This patient had a symptomatic occluded ICA on the left side. After the administration of acetazolamide, the patient’s blood flow in the MCA territory increased only by 2.1 mL/100 g/min on the left side (%Hem = 6.0%) and by 3.1 mL/100 g/min on the contralateral side (%Hem = 8.9%). As asymmetry was absent, the use of rCBF ratios (AIHem change = −2.7) would fail to identify a bilateral reduction of flow response to acetazolamide.
- Fig 5.
ROC curves used to determine the diagnostic accuracy of the AIHem change and the FIHem−Cbl change.
Tables
- TABLE 1:
Physiologic data in 133 patients measured during SPECT scanning at rest and with an acetazolamide challenge
Value At Rest Acetazolamide Challenge pH 7.39 ± 0.03 7.39 ± 0.04 PaCO2, mm Hg 41.8 ± 2.8 41.0 ± 2.5 PaO2, mm Hg 94.1 ± 2.7 94.9 ± 4.0 Mean blood pressure, mm Hg 96.1 ± 7.1 96.9 ± 8.1 Note.—Data are the mean ± SD.
- TABLE 2:
Values of %Hem, AIHem change, and FIHem−Cbl change in healthy volunteers and patients
Value Healthy Volunteers Patients P Value %Hem 36.8 ± 9.2 29.2 ± 18.7 .032 AIHem change 0.0 ± 4.2 −6.9 ± 8.7 .019 FIHem−Cbl change 0.000 ± 0.040 −0.051 ± 0.088 .012
