Magnetic resonance imaging applied to the assessment of intact yellowtail (Seriola quinqueradiata): Preliminary results

High‐quality food fish, such as yellowtail often pass through a distribution channels in an intact state. Thus, the quality and composition of the fish meat can only ascertained after processing. We investigated whether magnetic resonance imaging (MRI) could be feasibly used for quality and composition assessments of intact yellowtail. Selected factors at the ventral, lateral‐line, dorsal and blood‐colour regions of a pectoral‐fin slice and an anal slice from natural and cultured yellowtail (Seriola quinqueradiata) individuals were measured for comparison. Specifically, the fat fraction and T2* were measured using spoiled multi‐echo gradient echo with T2* correction on a 3T MRI scanner. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured using single‐shot diffusion echo‐planar imaging. T2 and fascial density were measured using T2‐weighted multi‐echo turbo spin‐echo. Fat fraction values at most regions were significantly higher in cultured yellowtail compared with natural fish. The highest fat fraction was observed at the ventral region of the pectoral‐fin slice. FA and T2 values were larger, while those for ADC and T2* were smaller in cultured yellowtail than in natural fish. Fascial densities did not differ significantly between the natural and cultured yellowtail except in the ventral region of the pectoral‐fin slice. MRI makes it possible to assess regional quality and composition of intact yellowtail.