Gamma knife treatment parameters and elapsed time to imaging and diagnosis*
| Final Diagnosis | GK Target Volume (mL) | IDL (mL) | IDL (%) | GK Dose (Gy) | Time to MRI (days)† | Time to Final Diagnosis (days)‡ | Imaging Follow-Up Time (days)§ |
| Recurrent tumor | 6.38 (5.2) | 8.14 (6.5) | 52 (0.7) | 16.85 (1.1) | 307 (149) | 432 (327) | 462 (195) |
| Radiation necrosis | 4.29 (3.7) | 5.46 (4.1) | 54 (0.1) | 17.55 (0.8) | 301 (118) | 353 (171) | 402 (237) |
| Welch P value | .22 | .18 | .61 | .06 | .89 | .40 | .86 |
Note:—IDL indicates isodose line.
* All data are presented in mean values (SD).
† Represents number of days elapsed between initial radiosurgery and perfusion MR imaging examination.
‡ Represents number of days elapsed between initial radiosurgery and final determination of metastatic tumor recurrence or radiation necrosis.
§ Represents number of days elapsed between time of clinical diagnosis and loss to follow-up or death.