Comparison between benign and malignant peripheral nerve sheath tumors using conventional and functional MRI and determination of interobserver agreement
| MPNST (n = 9) | BPNST (n = 22) | P Value | Interobserver Agreementa | |
|---|---|---|---|---|
| Diameter (cm) | ||||
| Maximum (mean) | 8 ± 2.4 | 5.6 ± 3.8 | .17 | 0.89 |
| Average (mean) | 6.3 ± 1.8 | 3.9 ± 2.3 | .009 | 0.82 |
| Conventional MRI | ||||
| T1 (Hyponintense to muscle) | 0% (0/9) | 14% (3/22) | .22 | 0.90 |
| T2 (Hyperintense to the muscle) | 100% (9/9) | 100% (21/22) | .99 | 0.98 |
| Following features present: | ||||
| Ill-defined or infiltrative margins | 77% (7/9) | 32% (7/22) | .04 | 0.66 |
| Irregular shape | 0% (0/9) | 12.5% (3/22) | .528 | 0.80 |
| Split fat sign | 10% (1/9) | 33% (8/22) | .11 | 0.21 |
| Target sign | 10% (1/9) | 21% (5/22) | .51 | 0.92 |
| T1 heterogeneity (<50%) | 0% (0/9) | 4% (1/22) | .49 | 0.76 |
| T2 heterogeneity (<50%) | 55% (5/9) | 29% (7/22) | .31 | 0.71 |
| Peritumoral edema | 66% (6/9) | 23% (5/22) | .01 | 0.71 |
| Eccentric to the nerve | 55% (5/9) | 42% (10/22) | .18 | 0.53 |
| Vascular encasement | 11% (1/9) | 0% (0/22) | .65 | 0.95 |
| Periosteal/cortical invasion | 11% (1/9) | 0% (0/22) | .65 | 1 |
| Bone marrow invasion | 0% (0/9) | 0% (0/22) | .99 | 1 |
| Joint extension | 0% (0/9) | 0% (0/22) | .99 | 1 |
| Delayed contrast enhancement | 100% (9/9) | 92% (22/22) | .39 | 0.70 |
| Functional MRI | ||||
| ADC values (×10−3 mm2/s) | ||||
| Average (mean) | 1.57 ± 0.27 | 1.7 ± 0.28 | .22 | 0.90 |
| Minimum (mean) | 0.47 ± 0.32 | 1.08 ± 0.26 | <.0001 | 0.89 |
| DCE-MRI | ||||
| Early arterial enhancement | 50% (4/8) | 11% (2/18) | .03 | 0.81 |
↵a Spearman rank-order correlation coefficient.