[Preparation of a Small Acute-phase Cerebral Infarction Phantom for Diffusion-weighted Imaging]

The present study aimed to prepare a small acute-phase cerebral infarction phantom made of gelatin and sucrose to simulate brain parenchymal cells, and a phantom made of collagen peptides and sucrose to simulate cerebral infarction for diffusion-weighted imaging (DWI). During the preparation of gelatin and sucrose mixture (17.0 wt% gelatin, 20.0 wt% sucrose), a cylindrical wooden bar was placed in the center of the phantom and covered with a heat-shrinkable film to ensure space remained after gelling. A mixed solution composed of collagen peptide and sucrose (16.0 wt% collagen peptide, 27.5 wt% sucrose) was then enclosed within the space. The T₂ relaxation time and apparent diffusion coefficient (ADC) of the phantom were set equal to those observed in actual patients with acute-phase cerebral infarction. The mixture was selected based on the signal intensity of both the healthy brain tissue and that subjected to acute cerebral infarction, such that no contrast was observed during T₂-weighted imaging (T₂WI). T₂WI and DWI were performed using a 1.5 T scanner. Although contrast between the mixed gel and mixed solution was obscure on T₂WI, cerebral infarction was clearly visible on DWI. However, the phantom exhibited mono-exponential changes in the ADC value at b values of 0 and 1,000 (s/mm²), and was affected by the proton density and T₁ value depending on the imaging condition.