The t1w1 high signal is the shortest t1 value, which is manifested as a high signal shadow in the image. The t1w1 of t1-weighted imaging refers to the high or low signal intensity of the tissue in the image, which mainly reflects the difference in longitudinal relaxation of the tissue. t1 relaxation represents the constant of the recovery time of the longitudinal magnetization vector. t1w1 is a t1-weighted image. t1w1 is usually used to observe the anatomical structures of the tissues. the shorter the value of t1 is, the higher is the signal intensity of it. Among human structures, aqueous structures such as cerebrospinal fluid and blood have the largest t1 values and therefore the lowest signal intensity. Adipose tissue has the smallest t1 value and therefore has the highest signal intensity, which appears as a high signal shadow in MRI. If the examination result shows t1w1 high signal, it is necessary to analyze whether it is normal or not according to where the high signal is located, and if there is any abnormality, it should be further examined according to the medical history and doctor’s instructions before making a diagnosis.