Effect of Slice Thickness for Apparent Diffusion Coefficient Measurement of Mass

• Published in: Japanese Journal of Radiological Technology Vol. 74; no. 8; pp. 805 - 809
• Main Authors: Asai, Ayumi, Ogura, Akio, Sotome, Hana, Fuju, Atsuya
• Format: Journal Article
• Language: English; Japanese
• Published: Japan Japanese Society of Radiological Technology 2018; Japan Science and Technology Agency
• Subjects: apparent diffusion coefficient (ADC); Chemotherapy; Diffusion; Diffusion coefficient; Diffusion Magnetic Resonance Imaging; diffusion weighted image (DWI); Field of view; Magnetic resonance imaging; magnetic resonance imaging (MRI); Materials management; Mathematical analysis; NMR; Nuclear magnetic resonance; Phantoms, Imaging; Radiation; Rapid prototyping; Signal-To-Noise Ratio; slice thickness; Thickness; Tumors; magnetic resonance imaging (MRI); apparent diffusion coefficient (ADC); slice thickness; diffusion weighted image (DWI)
• ISSN: 0369-4305; 1881-4883
• DOI: 10.6009/jjrt.2018_JSRT_74.8.805

Apparent diffusion coefficient (ADC) values calculated from diffusion-weighted magnetic resonance imaging (DW-MRI) can be used for differentiation of tumors. Clinically, ADC values are used for monitoring treatment response after chemotherapy or radiation. However, it is reported that the threshold of the ADC value differs among institutions. In addition, there are reports regarding the change factor of the ADC value. Slice thickness may induce error in the ADC value by the influence of the partial volume effect in thicker objects, and by the influence of signal-to-noise ratio (SNR) in thinner objects. Therefore, in this study, the effect of slice thickness was examined. The signal body of spherical high-diffusion coefficients of 6, 7.9, and 9.3 mm in diameter was fixed in the low-circumference material of the diffusion coefficient. These phantoms were imaged using DW imaging (DWI) of 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10, 15, and 20 mm slice thickness using the multi-b values. In addition, different SNR were imaged by changing field-of-view and the number of additions. ADC was calculated by DWI of the different b values. As a result, slice thickness showed a peak at 50–65% of the diameter of the signal body. Furthermore, ADC values fluctuated in the slice thickness in front of the peak with a change in SNR. In conclusion, the ADC value was most accurate at a setting of 50–65% of slice thickness for the object diameter.