MRI visualization of shiitake mycelium growing in woodchip blocks used for shiitake mushroom cultivation

In order to eliminate woodchip blocks where unwanted fungi have grown and select only blocks where shiitake mycelium are growing well, there is a need to develop a visualization technique for shiitake mycelium growing in woodchip blocks, and MRI is an obvious candidate technique. From the results of measurements of the woodchip bed in a small bottle (26 mm inside diameter) where shiitake mycelium was growing, the T₁ relaxation time constant immediately after inoculation was 77.9 ± 5.5 ms, and the value after about 10 to 20 days increased to 135.0 ± 9.8 ms (the increase rate was 73%). The T₁ maps of the wood-chip block (130 mm length, 75 mm height and 55 mm thickness) in which shiitake mycelium grew were calculated from T₁ weighted images measured by changing TR from 28 to 400 ms. From the T₁ maps of time series, it was found that the shiitake mycelium extended from the right-hand side to the left-hand side of the woodchip block in a planar manner. Furthermore, in a woodchip block in which penicillium was generated, since the T₁ relaxation time constant of only the shiitake mycelium became longer, it was possible to visualize the shiitake mycelium distinctly from penicillium.