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A potential risk of overestimating apparent diffusion coefficient in parotid glands.

Liu YJ, Lee YH, Chang HC, Huang TY, Chiu HC, Wang CW, Chiou TW, Hsu K, Juan CJ, Huang GS, Hsu HH - PLoS ONE (2015)

Bottom Line: A P value less than 0.05 was considered statistically significant.The mean error percentage decreased as the number of excitations increased on all images, and, it was smallest on T2WI, followed by DWI and ADC in an increasing order.Transient signal loss on DWI was successfully detected by dynamic EPDWI.

View Article: PubMed Central - PubMed

Affiliation: Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, Republic of China.

ABSTRACT

Objectives: To investigate transient signal loss on diffusion weighted images (DWI) and overestimation of apparent diffusion coefficient (ADC) in parotid glands using single shot echoplanar DWI (EPDWI).

Materials and methods: This study enrolled 6 healthy subjects and 7 patients receiving radiotherapy. All participants received dynamic EPDWI with a total of 8 repetitions. Imaging quality of DWI was evaluated. Probability of severe overestimation of ADC (soADC), defined by an ADC ratio more than 1.2, was calculated. Error on T2WI, DWI, and ADC was computed. Statistical analysis included paired Student t testing and Mann-Whitney U test. A P value less than 0.05 was considered statistically significant.

Results: Transient signal loss was visually detected on some excitations of DWI but not on T2WI or mean DWI. soADC occurred randomly among 8 excitations and 3 directions of diffusion encoding gradients. Probability of soADC was significantly higher in radiotherapy group (42.86%) than in healthy group (24.39%). The mean error percentage decreased as the number of excitations increased on all images, and, it was smallest on T2WI, followed by DWI and ADC in an increasing order.

Conclusions: Transient signal loss on DWI was successfully detected by dynamic EPDWI. The signal loss on DWI and overestimation of ADC could be partially remedied by increasing the number of excitations.

No MeSH data available.


A box-whisker plot shows probability of severe overestimation of ADC (ADC ratio > 1.2) in all parotid ROIs in healthy and radiotherapy (RT) groups.
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pone.0124118.g005: A box-whisker plot shows probability of severe overestimation of ADC (ADC ratio > 1.2) in all parotid ROIs in healthy and radiotherapy (RT) groups.

Mentions: Box-whisker plots of probabilities of soADC from all ROIs in both healthy and radiotherapy groups were shown on Fig 5. The probability of soADC was significantly higher in the radiotherapy group (42.86%) than the healthy group (24.39%) (P < 0.05).


A potential risk of overestimating apparent diffusion coefficient in parotid glands.

Liu YJ, Lee YH, Chang HC, Huang TY, Chiu HC, Wang CW, Chiou TW, Hsu K, Juan CJ, Huang GS, Hsu HH - PLoS ONE (2015)

A box-whisker plot shows probability of severe overestimation of ADC (ADC ratio > 1.2) in all parotid ROIs in healthy and radiotherapy (RT) groups.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414616&req=5

pone.0124118.g005: A box-whisker plot shows probability of severe overestimation of ADC (ADC ratio > 1.2) in all parotid ROIs in healthy and radiotherapy (RT) groups.
Mentions: Box-whisker plots of probabilities of soADC from all ROIs in both healthy and radiotherapy groups were shown on Fig 5. The probability of soADC was significantly higher in the radiotherapy group (42.86%) than the healthy group (24.39%) (P < 0.05).

Bottom Line: A P value less than 0.05 was considered statistically significant.The mean error percentage decreased as the number of excitations increased on all images, and, it was smallest on T2WI, followed by DWI and ADC in an increasing order.Transient signal loss on DWI was successfully detected by dynamic EPDWI.

View Article: PubMed Central - PubMed

Affiliation: Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, Republic of China.

ABSTRACT

Objectives: To investigate transient signal loss on diffusion weighted images (DWI) and overestimation of apparent diffusion coefficient (ADC) in parotid glands using single shot echoplanar DWI (EPDWI).

Materials and methods: This study enrolled 6 healthy subjects and 7 patients receiving radiotherapy. All participants received dynamic EPDWI with a total of 8 repetitions. Imaging quality of DWI was evaluated. Probability of severe overestimation of ADC (soADC), defined by an ADC ratio more than 1.2, was calculated. Error on T2WI, DWI, and ADC was computed. Statistical analysis included paired Student t testing and Mann-Whitney U test. A P value less than 0.05 was considered statistically significant.

Results: Transient signal loss was visually detected on some excitations of DWI but not on T2WI or mean DWI. soADC occurred randomly among 8 excitations and 3 directions of diffusion encoding gradients. Probability of soADC was significantly higher in radiotherapy group (42.86%) than in healthy group (24.39%). The mean error percentage decreased as the number of excitations increased on all images, and, it was smallest on T2WI, followed by DWI and ADC in an increasing order.

Conclusions: Transient signal loss on DWI was successfully detected by dynamic EPDWI. The signal loss on DWI and overestimation of ADC could be partially remedied by increasing the number of excitations.

No MeSH data available.