Purpose: To compare perfusion-free to perfusion-sensitive measurements of the apparent diffusion coefficient (ADC) to diagnose benign conditions from malignancies of the anterior mediastinum. Materials and Methods: Seventy-six subjects were divided into a “benign conditions” group (A, n 5 44) and a “malignancies” group (B, n 5 32), based on histological findings. diffusion-weightedmagnetic resonance imaging (DW-MRI) was performed at b of 0/150/800 sec/mm2. TheADCswereobtainedon anADCmapby including (perfusion-sensitive5 ADCb0-800) andexcluding(perfusion- free 5 ADCb150-800) the b 5 0 sec/mm2. The Mann–Whitney U-test was used to detect differences in ADCb0-800 compared with ADCb150-800 values between all cases, benign conditions, and malignancies. The same test was used to evaluate differences in ADCs between the two groups for each type of measurement (ADCb0-800 and ADCb150-800), and receiver-operating characteristic (ROC) curves were obtained to evaluate discrimination abilities with comparison of areas-under-ROC-curves (AUROC). Optimal cutpoints for discrimination between groups were determined by the Youden-Index with computation of accuracy. Results: The median ADCb0-800 was significantly greater compared with ADCb150-800 for all cases (P 5 0.0014), benign conditions (P 5 0.0412), and malignancies (P 5 0.0001). The median percentage of increase was 5.30% for group-A and 22.39% for group-B (P < 0.0001). AUROC of ADC in discriminating between groups was significantly greater for ADCb150-800 (0.932) compared with ADCb0-800 (0.831) (P 5 0.001). The optimal cutpoint for distinction between groups was 1.52 3 10-3mm2/sec (sensitivity 5 93.7%, specificity 5 88.6%, accuracy 5 90.8%) for ADCb150-800 and 1.75 3 10- 3mm2/sec (sensitivity 5 75.0%, specificity 5 79.5%, accuracy 5 77.6%) for ADCb0-800. Conclusion: The use of perfusion-free ADC measurements significantly improves diagnostic accuracy of DW-MRI in differentiating benign conditions from malignancies of the anterior mediastinum.
Diffusion-weighted quantitative MRI to diagnose benign conditions from malignancies of the anterior mediastinum: Improvement of diagnostic accuracy by comparing perfusion-free to perfusion-sensitive measurements of the apparent diffusion coefficient
PRIOLA, adriano massimiliano;PRIOLA, Sandro Massimo;GNED, Dario;PIACIBELLO, Edoardo;SARDO, Diego;TORTI, DAVIDE;ARDISSONE, Francesco;VELTRI, Andrea
Last
2016-01-01
Abstract
Purpose: To compare perfusion-free to perfusion-sensitive measurements of the apparent diffusion coefficient (ADC) to diagnose benign conditions from malignancies of the anterior mediastinum. Materials and Methods: Seventy-six subjects were divided into a “benign conditions” group (A, n 5 44) and a “malignancies” group (B, n 5 32), based on histological findings. diffusion-weightedmagnetic resonance imaging (DW-MRI) was performed at b of 0/150/800 sec/mm2. TheADCswereobtainedon anADCmapby including (perfusion-sensitive5 ADCb0-800) andexcluding(perfusion- free 5 ADCb150-800) the b 5 0 sec/mm2. The Mann–Whitney U-test was used to detect differences in ADCb0-800 compared with ADCb150-800 values between all cases, benign conditions, and malignancies. The same test was used to evaluate differences in ADCs between the two groups for each type of measurement (ADCb0-800 and ADCb150-800), and receiver-operating characteristic (ROC) curves were obtained to evaluate discrimination abilities with comparison of areas-under-ROC-curves (AUROC). Optimal cutpoints for discrimination between groups were determined by the Youden-Index with computation of accuracy. Results: The median ADCb0-800 was significantly greater compared with ADCb150-800 for all cases (P 5 0.0014), benign conditions (P 5 0.0412), and malignancies (P 5 0.0001). The median percentage of increase was 5.30% for group-A and 22.39% for group-B (P < 0.0001). AUROC of ADC in discriminating between groups was significantly greater for ADCb150-800 (0.932) compared with ADCb0-800 (0.831) (P 5 0.001). The optimal cutpoint for distinction between groups was 1.52 3 10-3mm2/sec (sensitivity 5 93.7%, specificity 5 88.6%, accuracy 5 90.8%) for ADCb150-800 and 1.75 3 10- 3mm2/sec (sensitivity 5 75.0%, specificity 5 79.5%, accuracy 5 77.6%) for ADCb0-800. Conclusion: The use of perfusion-free ADC measurements significantly improves diagnostic accuracy of DW-MRI in differentiating benign conditions from malignancies of the anterior mediastinum.
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