Article Figures & Data
Figures
- Fig 1.
Comparison of mean ADC values between groups with different tumor-progression statuses. There was a significant difference between the 2 groups (P < .001).
- Fig 2.
A 59-year-old man with a recurrent chordoma in the aggressive tumor group. A, Two years after the first surgery, contrast-enhanced T1-weighted imaging shows an expansile mass extending to the suprasellar region (arrows). B, The ROI outlined in yellow on the ADC map represents decreased water diffusivity (ADC = 1.211 × 10−3 × mm2/s). C, Contrast-enhanced T1-weighted imaging obtained 8 months later shows an increase of the mass (volume change ratio, 1.67; arrowheads) with a doubling time of 5.5 months. The patient died of disease 15 months after the second MR imaging examination.
- Fig 3.
A 10-year-old boy with a residual chordoma in the nonaggressive tumor group. A, Three years after the first operation, T2-weighted imaging shows an expansile mass in the clivus (arrows). B, The ROI outlined in yellow on the ADC map represents increased water diffusivity (ADC = 1.808 × 10−3 mm2/s). C, The mass was stable on T2-weighted imaging obtained 13 months later (volume change ratio = 0.11; arrowheads) with a doubling time of 10.0 years. He was still alive 7 years after the second MR imaging.
- Fig 4.
Kaplan-Meier curves using log-rank tests for survival. A, Graph shows 2 groups based on a cutoff ADC of 1.494 × 10−3 mm2/s at the first MR imaging. The group with the lower ADC had a significantly worse prognosis (P = .006). B, Graph shows the tumor progression rate in the 2 groups at the second MR imaging. The prognosis was significantly worse in the aggressive tumor group than in the nonaggressive tumor group (P < .001). The cutoff ADC value could predict patients with a worse prognosis at the first MR imaging at a mean of 9.1 ± 5.2 months earlier than the second MR imaging. Cum indicates cumulative.
Tables
Aggressive Tumor Nonaggressive Tumor P Value No. 6 10 Volume change ratio 14.4 ± 21.0 (−2.18–17.2) 0.463 ± 1.135 (−1.40–3.78) .003 Doubling time (mo) 5.77 ± 4.03 (0.73–10.8) NA Age at first operation (yr) 54.3 ± 9.9 45.8 ± 24.3 .713 Location of tumor (ratio of clival chordoma to all) 3/6 8/10 .299b Postsurgical RT radiation dose (Gy) 72.4 ± 33.5 (n = 4) 74.2 ± 10.9 (n = 7) .927 Ratio of patients with postsurgical RT to all 4/6 9/10 .518b Time from first operation to first follow-up MRI (mo) 62.8 ± 53.3 71.4 ± 76.2 >.99 Time between the 2 follow-up MRIs (mo) 9.1 ± 5.2 18.3 ± 12.5 .022 No. of surgical resections at first follow-up MRI 2.00 ± 0.89 1.10 ± 0.32 .056 Sex (M/F) 5:1 7:3 >.99b Histopathology (ratio of classic chordoma to all chordomas) 6/6 5/10 .093b Mean ADC (×10−3 × mm2/s) 1.055 ± 0.298 (0.78–1.37) 1.622 ± 0.139 (1.34–1.65) <.001 Tumor volume (× 103 × mm3) 21.2 ± 37.4 (0–60.4) 3.44 ± 2.38 (0–7.46) .492 - Table 2:
ROC plot analysis for ADC values differentiating an aggressive tumor from a nonaggressive tumora
Aggressive Tumor AUC (95% CI) 0.983 (0.911–1.000) (P = .002) Cutoff ADC value (×10−3 × mm2/s) 1.494 Sensitivity 1.000 (0.541–1.000) Specificity 0.900 (0.555–0.998) Accuracy 0.938 (0.698–0.998) PPV 0.857 (0.421–0.996) NPV 1.000 (0.664–1.000) Positive LR 10 (1.56–64.2) Negative LR 0 Note:—ROC indicates receiver operating characteristic; AUC, area under the curve; LR, likelihood ratio; NA, not available; NPV, negative predictive value; PPV, positive predictive value.
↵a Numbers in parentheses indicate 95% confidence intervals.
- Table 3:
Kaplan-Meier curves for survival using log-rank tests in patients with recurrent chordomas
Explanatory Variables Total No. No. of Events P Value Univariate models Age at first operation (yr) .312 Younger than 60 10 5 60 or older 6 2 No. of surgical resections at first MRI .002 1 11 3 ≥2 5 4 Tumor volume .957 <3 × 103 × mm3 10 4 ≥3 × 103 × mm3 6 3 Histopathology Chondroid chordoma 5 1 .346 Classic chordoma 11 6 Tumor location .507 Clivus 11 5 Other sites 5 (C = 1, L = 2, S = 1, other = 1) 2 Adjuvant radiation therapy .172 None/unknown 3 2 Done 13 5 Mean ADC (for an aggressive tumor) .006 >1.494 × 10−3 × mm2/s 10 2 ≤1.494 × 10−3 × mm2/s 6 5 Note:—C indicates cervical spine; L, lumber spine; S, sacrum.
