Object ID: 00000018WIA30DC8970GYZ
Topic ID: id_40024635 Version: 1.3
Date: Mar 28, 2022 1:51:22 PM

BrainStat algorithms

Figure 1. Measurement of signal intensity

Table 1. BrainStat AIF and BrainStat equations
Equation	BrainStat AIF	BrainStat
CBV
CBF
MTT
table legend	p = density of brain tissue R(t) = Residue function kH = correction factor

Gamma variate fitting

BrainStat using gamma variate fitting eliminates tracer re-circulation effects.

Relative Blood Flow

Relative Corrected Blood Flow (rCBF) quantifies the volume of arterial blood delivered to a given mass of tissue per unit time, thus representing instantaneous capillary flow in tissue.

Figure 3. rCBF: ratio of the integrated area to the time (GVF)or estimated as Peak of R(t) (AIF

Relative Blood Volume

Relative Blood Volume (rCBV) describes the blood volume of the cerebral capillaries and venules (not arteries) per cerebral tissue volume.

Figure 4. rCBV: integrated area of the signal intensity change (GVF) or estimated as area under the curve (AUC) of R(t) (AIF)

Mean Transit Time

Mean Transit Time (MTT) measures the length of time a certain volume of blood spends in the cerebral capillary circulation.

Figure 5. MTT: time from the beginning of the change of intensity to the end of the intensity change (GVF) or estimated as weight center (1st moment) of R(t) (AIF)

Time to Peak

Time To Peak is inversely related to CBF in which reduction of blood flow results in an increase in the time needed for the contrast to reach its peak in brain tissue.

Figure 6. TTP: time from the origin of the curve to the maximum amplitude of the signal intensity change

Bolus Arrival Time

Bolus Arrival Time (BAT): time from scan start to tracer bolus arrival of bolus at tissue.

Figure 7. BAT map: time from the start of the scan to the arrival of the contrast bolus at the tissue

Tmax

Time to maximum value of Residue function (Tmax). This represents the tracer delay effect at a pixel.