Details of the MRI protocol.

<p>DWI: diffusion-weighted imaging.</p><p>EPI: echo planar imaging.</p><p>FOV: field of view.</p><p>NA: not applicable.</p><p>NSA: number of signal averages.</p><p>SE: spin-echo.</p><p>STIR: short TI inversion recovery.</p><p>TSE: turbo spin-echo.</p

Tumor type, initial clinical tumor stage, whether or not undergoing 1st/2nd MRI scan, visibility of tumor at DWI scan, results of histopathological analysis, and tumor response to neoadjuvant therapy for all patients.

<p>*: Some degree of signet ring cell differentiation was encountered.</p><p>NA: not applicable.</p

Manual measurement method.

<p>T2-weighted (A) and b1000 DW (B) images, and corresponding ADC map (C and D). An esophageal tumor can be depicted as thickening of the esophageal wall (arrow in (A) with high signal intensity on the corresponding b1000 DW image (arrow in B) and low signal intensity on the corresponding ADC map (arrow in C). An ROI was manually drawn in the tumor on the ADC map (red circular region in D) to calculate the tumor ADC value.</p

Scatter plots of percentage change in mean tumor ADC value between the first and second MRI scan (x-axis) and TRG score (y-axis), both for the manual (A) and semi-automated measurements (B).

<p>Scatter plots of percentage change in mean tumor ADC value between the first and second MRI scan (x-axis) and TRG score (y-axis), both for the manual (A) and semi-automated measurements (B).</p

Box plots show the distribution of mean pretreatment ADC values (A) and percentage change in ADC value (B), as measured by the manual method, for patients with and without tumor response.

<p>Box plots show the distribution of mean pretreatment ADC values (A) and percentage change in ADC value (B), as measured by the manual method, for patients with and without tumor response.</p

Interobserver reproducibility using the manual measurement method.

<p>Measurements from both the first and second MRI scan were included in this analysis. Bland-Altman plot shows the difference between measurements of two observers (R.F.A.V. and S.S.) against the average measurement, with mean absolute difference (continuous line) and 95% CI of the mean difference (dashed lines).</p

Timing of neoadjuvant therapy, surgery, and MRI (timing of MRI scans is indicated by asterisks and arrowheads).

<p>Timing of neoadjuvant therapy, surgery, and MRI (timing of MRI scans is indicated by asterisks and arrowheads).</p

Semi-automated measurement method. B1000 DW image (A and C) and corresponding ADC map (B and D).

<p>An esophageal tumor can be depicted as an area of high signal intensity centrally at the b1000 DW image (arrow in A) and as an area of low signal intensity centrally at the corresponding ADC map (arrow in B). After visually selecting a threshold, the software automatically placed an ROI (area bordered by a yellow line in C) around the tumor at the b1000 DW image, which was then copied to the corresponding ADC map (D) to calculate the tumor ADC value.</p

Scatter plots of mean pretreatment tumor ADC value (x-axis) and TRG score (y-axis), both for the manual (A) and semi-automated measurements (B).

<p>Scatter plots of mean pretreatment tumor ADC value (x-axis) and TRG score (y-axis), both for the manual (A) and semi-automated measurements (B).</p

Agreement between the manual and semi-automated method in measuring mean tumor ADC.

<p>Measurements from both the first and second MRI scan were included in this analysis. Bland-Altman plot shows the difference between the manual and semi-automated measurements against the average measurement, with mean absolute difference (continuous line) and 95% CI of the mean difference (dashed lines).</p