Imaging of Hematoma and Perihematomal Edema in Experimental Intracerebral Hemorrhage - Animal Models of Acute Neurological Injuries: Injury and Mechanistic Assessments - page 667

pronounced employing EPI DWI sequences. Strbian et al. proposed
to image the clot with T2-weighted images which were acquired
using rapid acquisition with a relaxation enhancement (RARE)
sequence ( 18 ).
When using MRI for repeated imaging, the changing MRI
characteristics of the clot with time, which has been detailed by Del
Bigio et al. as early as 1996, have to be taken into consideration.
These MRI changes are related to the gradual degradation of oxy-
hemoglobin via intra- and extracellular deoxyhemglobin, methe-
moglobin to hemosiderin and the thereby changing T2 and T1
effects ( 14 ).
Irrespective of the used sequences, hematoma volumes were
consistently calculated by tracking the boundaries of the hema-
toma manually or semiautomatically and multiplying the cross-
sectional area on each slice with the slice thickness.

For evaluation of the perihematomal edema, T2-weighted fl uid
attenuation inversion recovery sequences (FLAIR) and standard
T2-weighted images have been proven to be reliable (Fig. 2 )
( 5, 14 ). The edema volume is calculated by tracking the outer
boundaries of the perihematomal edema, multiplying the surface

3.1.2. Evaluation
of the Edema Volume

Fig. 2. T2-weighted fl uid attenuation inversion recovery sequences (FLAIR) have been
proven to be reliable for the detection of perihematomal edema.