In order to correlate the yield and quality of shiitake mushrooms with the growth process of shiitake mycelium in logs over several years, a non-invasive visualization method using a magnetic resonance imaging (MRI) measurement system was developed. The MRI measurement system had a permanent magnet of 1.0 T magnetic field strength and a 110 mm air gap. The test logs in which grew the shiitake mycelium had a diameter of 43–48 mm, a length of 110–118 mm and a dried mass of 125–135 g. The log was inoculated on one cutting surface after being supplied water, and was placed in a thermostatic chamber (21 °C, about 75% humidity) for 69 days. The test log was observed by MRI, and MR images and T₁ maps of shiitake mycelium growing over time were obtained. It was found that the shiitake mycelium has a T₁ relaxation time constant longer than 150–200 ms, and its signal intensity in the MR images is smaller than that of water penetrated into a log. When making the MRI measurements, it is necessary to dry a log to water content of about 20% or less. In addition, a control log with mold was also observed by MRI. The shiitake mycelium can be distinguished from water penetrated into log and mold occurring in the log by combining the T₁—signal intensity map and clear recognition of a low-intensity region in MR images acquired at longer echo times.

为了使香菇的产量和品质与香菇菌丝体在数年内的生长过程相关联，开发了一种使用磁共振成像（MRI）测量系统的无创可视化方法。MRI测量系统具有1.0 T磁场强度的永久磁铁和110 mm的气隙。生长香菇菌丝体的原木直径为43-48毫米，长度为110-118毫米，干燥质量为125-135克。供应原木后，将原木接种在一个切割面上，并将其放置在恒温室（21°C，约75％的湿度）中69天。通过MRI观察测试日志，并获得香菇菌丝体随时间生长的MR图像和T ₁图。发现香菇菌丝具有T ₁弛豫时间常数大于150–200 ms，其MR图像中的信号强度小于渗入测井仪中的水的信号强度。进行MRI测量时，有必要将原木干燥至水分含量不超过20％左右。另外，还通过MRI观察到带有霉菌的对照日志。通过结合T _1-信号强度图和在较长回波时间获得的MR图像中的低强度区域的清晰识别，可以将香菇菌丝体与渗入圆木和渗入圆木中的霉菌的水区分开。