Dynamic contrast-enhanced MRI in orbital lymphoproliferative disorders: Effects of region of interest selection methods on time efficiency, measurement reproducibility, and diagnostic ability.

BACKGROUND

Previous studies indicated that dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) could serve as a useful biomarker for differentiating malignant from benign orbital lymphoproliferative disorders (OLPDs).

PURPOSE

To investigate the influence of different region of interest (ROI) selection methods on the measurements of DCE-MRI parameters, and their diagnostic ability in discriminating malignant from benign OLPDs.

STUDY TYPE

Retrospective study.

POPULATION

In all, 46 patients with OLPDs (22 benign and 24 malignant).

FIELD STRENGTH/SEQUENCE: 3.T DCE-MRI using a 2D turbo fast low angle shot sequence postcontrast.

ASSESSMENT

DCE-MRI data were analyzed using three different ROI selection methods, including whole-tumor ROI (ROI ), single-slice ROI (ROI ) and hot-spot ROI (ROI ). Quantitative parameters (K , K , V ) were calculated based on a modified Tofts model.

STATISTICAL TESTING

Analysis of variance test, intraclass correlation coefficient (ICC), Bland-Altman plots, independent t-test, and receiver operating characteristic curve analyses were used for statistical analyses.

RESULTS

The time required for outlining ROI was significantly longer than ROI and ROI (P < 0.001). The measurements of DCE-MRI-derived parameters based on ROI demonstrated lowest ICC, followed by ROI and ROI . Malignant OLPDs showed significantly higher K than benign mimics (P < 0.001), while no significant differences were found on K (ROI , P = 0.535; ROI , P = 0.557; ROI , P = 0.400) and V (ROI , P = 0.071; ROI , P = 0.079; ROI , P = 0.057). K -ROI showed the highest area under curve for differentiating malignant from benign OLPDs, followed by K -ROI , and Kep-ROI ; however, the differences were not significant (ROI vs. ROI , P = 0.407; ROI vs. ROI , P = 0.363; ROI vs. ROI , P = 0.887).

DATA CONCLUSION

ROI selection methods could have an influence on the measurements of DCE-MRI parameters. Taking measurement time, reproducibility, and diagnostic ability into account, we suggest single-slice ROI to be used for differentiating malignant from benign OLPDs in clinical practice.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1298-1305.