Diffusion‐weighted MR imaging of upper abdominal organs at different time points: Apparent diffusion coefficient normalization using a reference organ

Abstract

5 J. MAGN. RESON. IMAGING 2017;45:1494-1501.

Diffusion-Weighted Imaging of Upper Abdominal Organs Acquired with Multiple B-Value Combinations: Value of Normalization Using Spleen as the Reference Organ

“…Although direct comparison of mean ADC values obtained in this study with those reported previously may be inappropriate due to differences in patient cohort and DWI acquisition techniques, the mean of normalized ADC obtained in this study was within range of values reported previously. In our study, highest normalized ADC was obtained for kidneys (2.182–2.310 vs. 2.214–2.279 reported previously) and lowest value was obtained for the right liver lobe (1.168–1.214 vs. 1.303–1.348 reported previously, respectively) ( 17 28 ). CV of the original ADC (4.8–8.8%) and normalized ADC (3.0–3.8%) was within the range reported in previous studies (6.9–11.1% for original ADC and 2.4–5.5% for normalized ADC) ( 17 28 ).…”

“…In our study, highest normalized ADC was obtained for kidneys (2.182–2.310 vs. 2.214–2.279 reported previously) and lowest value was obtained for the right liver lobe (1.168–1.214 vs. 1.303–1.348 reported previously, respectively) ( 17 28 ). CV of the original ADC (4.8–8.8%) and normalized ADC (3.0–3.8%) was within the range reported in previous studies (6.9–11.1% for original ADC and 2.4–5.5% for normalized ADC) ( 17 28 ). Additionally, CVs of normalized ADC was significantly lower than that of the original ADC, suggesting that normalized ADC reduced variability in multiple b-value combinations compared to the original ADC.…”

“…A recent study suggested the possibility of normalizing ADC values of upper abdominal organs using the spleen as the reference organ in two different 3T MR systems within a patient cohort ( 28 ). Another study demonstrated good agreement between three MR examinations at different time points with variable DWI acquisition techniques when normalizing ADC values of the upper abdominal organs using the spleen as a reference organ ( 17 ). However, that study was limited in that most of the ADCs (81%) were acquired with two b-value combinations (b = 0, 50, 400, 800 and 0, 50, 600 s/mm 2 ).…”

“…In addition, the ADC values of the kidney can be measured either from the cortex or medulla. Some studies have provided separate ADC measurements for the cortex and medulla, while others have not ( 15 17 33 ). In this study, we did not differentiate between the cortex and medulla.…”

“…Apparent diffusion coefficient values are influenced by many factors that may be related to patients, hardware, acquisition parameters, motion artifacts, and susceptibility effects ( 15 16 ). A recent study of patients that underwent three rounds of MRI scans at different time points with variable b-value combinations and respiratory motion compensation techniques revealed that normalized ADC using the spleen as the reference organ significantly decreased variability in ADC measurement of upper abdominal organs ( 17 ). However, findings of that study were limited in that most of the ADCs (81%) were acquired with two b-value combinations (b = 0, 50, 400, 800 and 0, 50, 600 s/mm 2 ).…”